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Articles 5881 - 5910 of 14175

Full-Text Articles in Engineering

Deposition Of Rust Particles On Stainless Steel Surface, Taweechai Watcharapiboon Jan 2018

Deposition Of Rust Particles On Stainless Steel Surface, Taweechai Watcharapiboon

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research investigates deposition behavior of rust particles in ethylene glycol solution onto surface of stainless steel. The study includes effects of contact time of the solution on the surface, flow velocity, particles size and particle concentration in the solution, on the thickness of rust particle film on the surface. According to results, thickness of rust particle film increases as the immersing is prolonged. The film thickness becomes constant at about 100 day. The increased solution velocity, the decreased size of rust particles and the reduce in the particle concentration, cause the adhesion of the particles on the surface is …


ผลของปริมาณเยื่ออะรามิดและเส้นใยคาร์บอน ต่อสมบัติไทรโบโลยีในวัสดุพอลิเบนซอกซาซีนคอมพอสิทเสริมแรงด้วยเส้นใย, วิชชุกร เลิศวาสนา Jan 2018

ผลของปริมาณเยื่ออะรามิดและเส้นใยคาร์บอน ต่อสมบัติไทรโบโลยีในวัสดุพอลิเบนซอกซาซีนคอมพอสิทเสริมแรงด้วยเส้นใย, วิชชุกร เลิศวาสนา

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มีวัตถุประสงค์เพื่อพัฒนาวัสดุพอลิเบนซอกซาซีนคอมพอสิทที่เสริมแรงด้วยเยื่ออะรามิดและเส้นใยคาร์บอน เพื่อใช้เป็นวัสดุเสียดทานผ้าเบรกรถยนต์แทนการใช้แร่ใยหิน เนื่องจากแร่ใยหินส่งผลกระทบต่อสุขภาพในเชิงลบเมื่อมีการเข้าสู่ร่างกายผ่านระบบทางเดินหายใจ ดังนั้นงานวิจัยฉบับนี้จึงทำการศึกษาและนำเสนอการใช้เยื่ออะรามิดและเส้นใยคาร์บอน ทดแทนการใช้แร่ใยหิน อีกทั้งศึกษาผลของปริมาณเยื่ออะรามิดและเส้นใยคาร์บอนที่สัดส่วนเยื่ออะรามิดต่อเส้นใยคาร์บอนต่างๆ ดังนี้ 100:0 75:25 50:50 25:75 และ 0:100 เปอร์เซ็นต์โดยน้ำหนัก ต่อสมบัติทางความร้อน สมบัติทางกลและสมบัติทางไทรโบโลยีของวัสดุพอลิเบนซอกซาซีนคอมพอสิท จากการศึกษาพบว่า วัสดุพอลิเบนซอกซาซีนคอมพอสิทเสริมแรงด้วยเยื่ออะรามิดและเส้นใยคาร์บอน ที่สัดส่วน 75:25 โดยน้ำหนัก มีค่าสัมประสิทธิ์ความเสียดทานอยู่ในช่วง 0.34−0.44 ซึ่งเป็นไปตามมาตรฐานผลิตภัณฑ์อุตสาหกรรมผ้าเบรกสำหรับยานยนต์ (มอก. 97-2557) รวมทั้งมีอัตราการสึกหรอจากการใช้งานมีค่าต่ำอยู่ในช่วง 0.13x10-7 − 1.12x10-7 ลูกบาศก์เซนติเมตรต่อนิวตันเมตร ในช่วงอุณหภูมิ 100−350 องศาเซลเซียส ส่งผลให้วัสดุพอลิเบนซอกซาซีนคอมพอสิทนี้สามารถทนแรงเสียดทานและการสึกหรอได้ดีขึ้น นอกจากนี้วัสดุพอลิเบนซอกซาซีนคอมพอสิทยังมีเสถียรภาพทางความร้อนและทางกลที่โดดเด่น โดยมีอุณหภูมิการสลายตัวทางความร้อนที่การสูญเสีย 5 เปอร์เซ็นต์โดยน้ำหนัก เท่ากับ 420 องศาเซลเซียส มีอุณหภูมิเปลี่ยนสถานะคล้ายแก้ว มีค่าเท่ากับ 219 องศาเซลเซียส และค่าความแข็งแรงภายใต้แรงดัดโค้งสูงถึง 68.5 เมกกะปาสคาล ดังนั้นจากสมบัติทางไทรโบโลยีและความเสถียรภาพทางความร้อนและทางกลที่ดีจึงมีความเป็นไปได้อย่างยิ่งที่จะนำวัสดุพอลิเบนซอกซาซีนคอมพอสิทที่เสริมแรงด้วยเยื่ออะรามิดและเส้นใยคาร์บอน ที่สัดส่วน 75:25 โดยน้ำหนัก มาประยุกต์ใช้เป็นวัสดุเสียดทานผ้าเบรกรถยนต์ได้


แบตเตอรี่อะลูมิเนียม-อากาศแบบอิเล็กโทรไลต์คู่ไหลโดยใช้สารละลายเอทานอล/เอทิลีนไกลคอลเป็นอะโนไลต์, ธนวัฒน์ ภูษิตธนานันท์ Jan 2018

แบตเตอรี่อะลูมิเนียม-อากาศแบบอิเล็กโทรไลต์คู่ไหลโดยใช้สารละลายเอทานอล/เอทิลีนไกลคอลเป็นอะโนไลต์, ธนวัฒน์ ภูษิตธนานันท์

Chulalongkorn University Theses and Dissertations (Chula ETD)

แบตเตอรี่อะลูมิเนียม-อากาศได้รับความสนใจอย่างมากในปัจจุบัน เนื่องจากมีความจุจำเพาะตามทฤษฎีสูงถึง 2,980 mAh/g ต้นทุนต่ำ เป็นมิตรกับสิ่งแวดล้อม และมีปริมาณมากบนโลก แต่อย่างไรก็ตาม การกัดกร่อนตัวเองของอะลูมิเนียมในสารละลายแอลคาไลน์เป็นปัญหาสำคัญที่มีผลต่อข้อกำจัดในการนำไปประยุกต์ใช้งาน สารละลายเอทานอลสามารถยับยั้งการเกิดแก๊สไฮโดรเจนได้ เนื่องจากความว่องไวในการทำปฏิกิริยาของโปรตอนในเอทานอลมีค่าน้อยกว่าของน้ำ แต่ความว่องไวในการทำปฏิกิริยาของสารละลายเอทานอลยังต่ำเกินกว่าจะใช้งานในแบตเตอรี่อะลูมิเนียม-อากาศ สำหรับงานวิจัยนิ้ได้ศึกษาสารละลายอิเล็กโทรไลต์ของเอทิลีนไกลคอลต่อเอทานอลที่อัตราส่วนร้อยละ 0, 5, 10, 20 และ 30 โดยปริมาตร โดยมีโพแทสเซียมไฮดรอกไซด์เข้มข้น 3 โมลาร์ ตลอดจนศึกษาการประยุกต์ใช้งานสารละลายอิเล็กโทรไลต์ในแบตเตอรี่อะลูมิเนียม-อากาศแบบอิเล็กโทรไลต์คู่ไหล การทดลองดำเนินการโดยใช้ระบบอิเล็กโทรไลต์คู่ที่มีการไหลของสารละลายแอโนไลต์ ซึ่งโครงสร้างของแบตเตอรี่ประกอบไปด้วย อะลูมิเนียมแอโนด | แอโนไลต์ || เยื่อแลกเปลี่ยนไอออน || แคโทไลต์ | ขั้วอากาศแคโทด จากผลการศึกษาพบว่าอัตราส่วนของเอทิลีนไกลคอลเป็นตัวกำหนดการกัดกร่อนตัวเองของอะลูมิเนียม เอทิลีนไกลคอลส่งผลดีต่อระบบแบตเตอรี่โดยลดการเกิดชั้นฟิล์มระหว่างอลูมิเนียมกับสารละลายแอโนไลต์ พร้อมกับลดค่าศักย์ไฟฟ้าส่วนเกินของขั้วแอโนด อย่างไรก็ตาม เอทิลีนไกลคอลเพิ่มการกัดกร่อนตัวเองของอะลูมิเนียม และเพิ่มการเกิดแก๊สไฮโดรเจน นอกจากนี้แบตเตอรี่อะลูมิเนียม-อากาศที่ประกอบด้วยเอทิลีนไกลคอลร้อยละศูยน์โดยปริมาตร มีอัตราการไหลของแอโนไลต์ 160 มิลลิลิตรต่อนาที ที่การคายประจุคงที่ 5 มิลลิแอมป์ต่อตารางเซนติเมตร ให้ค่าความจุจำเพาะสูงสุดอยู่ที่ 2,100 มิลลิแอมป์ชั่วโมงต่อกรัม คิดเป็นร้อยละการใช้อะลูมิเนียมที่ 70.5 อย่างไรก็ตาม ค่าศักย์ไฟฟ้าของแบตเตอรี่มีค่าต่ำ เนื่องจาการเกิดชั้นออกไซด์ฟิล์มบนผิวหน้าของอะลูมิเนียม ค่าความจุจำเพาะของแบตเตอรี่ลดลงเมื่อเพิ่มปริมาณของเอทิลีนไกลคอล แต่ค่าศักย์ไฟฟ้าของแบตเตอรี่นั้นเพิ่มสูงขึ้น นอกจากนี้ค่าศักย์ไฟฟ้าของแบตเตอรี่เพิ่มขึ้น เมื่ออัตราการไหลของแอโนไลต์เพิ่มขึ้นอีกด้วย


Toxicological Inhalation Effects Of Metal-Based Nanoparticle Aerosols As Studied By A Portable In Vitro Exposure Cassette, Lynn E. Secondo Jan 2018

Toxicological Inhalation Effects Of Metal-Based Nanoparticle Aerosols As Studied By A Portable In Vitro Exposure Cassette, Lynn E. Secondo

Theses and Dissertations

The toxicology of aerosols in occupational settings is often performed through particle collection on a filter followed by reconstitution into cell culture media which can alter the biological effects. Current in vitro exposure systems require additional instruments to control temperature and humidity, making the system bulky and difficult to take to the field. The Portable In Vitro Exposure Cassette (PIVEC) was designed for personal monitoring, characterized using copper nanoparticles, tested with alveolar cells, and set-up for real-time monitoring. Three differently sized copper nanoparticles, 40-800 nm, were dispersed as a dry aerosol and measured gravimetrically and on a number concentration basis …


Process Optimization For The Synthesis Of Gold Nanoparticles From A Mixed Metal Precursor Solution, Kathryn Ann Dill Jan 2018

Process Optimization For The Synthesis Of Gold Nanoparticles From A Mixed Metal Precursor Solution, Kathryn Ann Dill

Theses and Dissertations

Separation methods involving a mixture of metals typically include upfront processing that leads to one final product. To lower the waste and ultimately environmental burden, the potential to synthesize multiple functional products from a mixed metal precursor solution is explored. The initial precursor solutions contained varying ratios of gold and copper, gold and nickel, and finally a ternary solution of gold, copper, and nickel. The amount of gold was kept constant, while the amount of copper and/or nickel was sequentially increased. Two separate synthesis processes were tested, the traditional Turkevich method involving trisodium citrate and another chemical reduction method involving …


Metabolic Engineering Of Serratia Marcescens, Qiang Yan Jan 2018

Metabolic Engineering Of Serratia Marcescens, Qiang Yan

Theses and Dissertations

The potential value of the chitin biomass (e.g. food waste) is recently considered being ignored by landfill. Chitin can be a potential cheap carbon source for converting into value-added chemicals by microorganisms. Serratia marcescens is a chitinolytic bacterium that harbors endogenous chitinase systems. With goals of characterzing S. marcescens chitinolytic capabilities and applying S. marcescens to chemical production from chitin, my dissertation main content includes five chapters: 1) Chapter 1 highlights background information of chitin source, S. marcescens and potential metabolic engineering targets using chitin as a substrate; 2) Chapter 2 demonstrates that ChiR is a key regulator in regulating …


Graphene As A Solid-State Ligand For Palladium Catalyzed Cross-Coupling Reactions, Yuan Yang Jan 2018

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 …


Investigation Of Combustion Characteristics Of A Heavy-Duty Diesel Engine Retrofitted To Natural Gas Spark Ignition Operation, Jinlong Liu Jan 2018

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 …


Applications Of Cellular Components In Engineered Environments, Xiao Hu Jan 2018

Applications Of Cellular Components In Engineered Environments, Xiao Hu

Graduate Theses, Dissertations, and Problem Reports (ETD)

Manipulation of cellular components in synthetic environment has attracted interest for applications ranging from sensors to nanelectronics and from catalysis to biomedical devices. In such applications, biological-based processes such as specific recognition and self-assembly direct the formation of hierarchical structures, all at minimum energetic costs, with high efficiency and reliability.

Among such cellular machines, microtubules and kinesins have attracted special interest. Inside the cells, microtubules are giving structural integrity while serving as regular and uniform tracks for transport of vesicles or organelles. Kinesin uses a microtubule track in vivo to progress to specific locations with processive and coordinated steps, all …


The Rational Synthesis Of Bimetallic Catalysts On Oxide Supports, Andrew Phillip Wong Jan 2018

The Rational Synthesis Of Bimetallic Catalysts On Oxide Supports, Andrew Phillip Wong

Theses and Dissertations

Catalysts play an important role in many chemical reactions. However, simple impregnated monometallic catalysts are often limited in their function. One way to overcome this limitation is through the incorporation of a secondary metal to the catalysts. These bimetallic catalysts often have synergistic benefits not observed in the monometallic analogues. Here, we focused on the synthesis of bimetallic catalysts using rational methods in order to improve catalyst function; specifically by tuning the particle size, morphology, and composition. The two methods of interests were Strong Electrostatic Adsorption (SEA) and Electroless Deposition (ED). An adaptation of SEA to bimetallic catalysts (coSEA) was …


Combinatorial Study Of Oxidation Catalysts: Uncovering Synthesis-Structure-Activity Relationships, Kathleen B. Mingle Jan 2018

Combinatorial Study Of Oxidation Catalysts: Uncovering Synthesis-Structure-Activity Relationships, Kathleen B. Mingle

Theses and Dissertations

High throughput experimentation (HTE) in catalysis has proven useful in expediting materials discovery via parallelized synthesis, characterization, and testing of candidate materials. However, even in a high-throughput manner, the combinatorial explosion of relevant parameters far exceeds our ability to study. To further complicate the problem, a large time investment and great deal of characterization is often required to build an in-depth understanding of catalytic materials. It follows that the field of heterogeneous catalysis is rich with examples of catalytic systems that have been developed using trial and error efforts for which a lot is known but context is lacking. Techniques …


Role Of Bed Design Characteristics On The Effective Thermal Conductivity Of A Structured Adsorbent, Pravin Bosco Charles Antony Amalraj Jan 2018

Role Of Bed Design Characteristics On The Effective Thermal Conductivity Of A Structured Adsorbent, Pravin Bosco Charles Antony Amalraj

Theses and Dissertations

This work evaluates the role of different design variables on the effective thermal conduction of a structured adsorbent bed for its possible application in a temperature swing adsorption (TSA) process. The structured adsorbent bed is represented by eight parallel layers of intercalated smooth and corrugated foils of a metal support coated with 13X zeolite resulting in the formation of parallel triangular channels. The variables investigated include the thickness of the adsorbent coating, thickness of the metal, nature of contacts between smooth and corrugated foils, type of metal, presence and magnitude of an air gap between the foils, difference in alignment …


Nox Formation In Syngas/Air Combustion, Nazli Asgari Jan 2018

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 …


Three-Way Catalysts In Passive Selective Catalytic Reduction Systems, Calvin Thomas Jan 2018

Three-Way Catalysts In Passive Selective Catalytic Reduction Systems, Calvin Thomas

Theses and Dissertations

Conventional gasoline-powered engines operate with a stoichiometric air-fuel ratio (AFR), but greater fuel economy is achieved in lean burn engines by increasing the AFR. The primary drawback to these engines is the nitrogen oxide (NOX) emissions, which cannot be reduced over a conventional three-way catalyst (TWC). Passive selective catalytic reduction (SCR) is a promising approach for the control of NOX emissions in lean burn systems. By periodically decreasing the AFR to fuel-rich levels, ammonia (NH3) can be produced over a TWC and stored on a downstream SCR catalyst for the reduction of NOX during normal lean operation. While passive SCR …


Understanding Early Amyloid-Ss Aggregation To Engineer Polyacid-Functionalized Nanoparticles As An Inhibitor Design Platform, Nicholas Vander Munnik Jan 2018

Understanding Early Amyloid-Ss Aggregation To Engineer Polyacid-Functionalized Nanoparticles As An Inhibitor Design Platform, Nicholas Vander Munnik

Theses and Dissertations

Alzheimer’s disease (AD) is characterized by the presence of amyloid-ß (Aß) protein aggregates in the brains of those afflicted. This protein aggregates via a complex pathway to progress from monomers to soluble oligomers and ultimately insoluble fibrils. Due to the dynamic nature of aggregation, it has proven exceedingly difficult to determine the precise interactions that lead to the formation of transient oligomers. A statistical thermodynamic model has been developed to elucidate these interactions. Aß was simulated using fully-atomistic replica exchange molecular dynamics. We use an ensemble of 5 × 105 configurations taken from these simulations as input for a self-consistent …


Hydrodeoxygenation Of Acetic Acid Using Monometallic And Bimetallic Catalysts Supported On Carbon, José Luis Contreras Mora Jan 2018

Hydrodeoxygenation Of Acetic Acid Using Monometallic And Bimetallic Catalysts Supported On Carbon, José Luis Contreras Mora

Theses and Dissertations

Heterogeneous catalytic hydrodeoxygenation (HDO) of biomass-derived feeds is a deoxygenation process that is of highly interest. Carboxylic acids are one of the main components of bio-oils and acetic acid is one of the most abundant of these carboxylic acids. This acid is rich in oxygen, therefore a lot of research to produce fuel and other valuable chemicals such as ethanol is of interest.

This dissertation explores the gas-phase catalytic HDO of AA over catalysts supported on activated carbon (Cp-97). Temperature-dependent conversion and selectivity were studied at 1 atm from 200-4000C with an AA concentration of 1.1% and 20% …


Development Of Bimetallic Catalysts For Dry Reforming Of Methane And Hydrogenation Of Succinic Acid, Jayson Michael Keels Jan 2018

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 …


Dynamic Simulation Of A Solar Powered Hybrid Sulfur Process For Hydrogen Production, Satwick Boddu Jan 2018

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 …


Effects Of Ag Promotion And Preparation Method On Cobalt Fischer- Tropsch Catalysts Supported On Silica-Modified Alumina, Mahmood Rahmati, Baiyu Huang, Landon M. Schofield, Thomas H. Fletcher, Brian F. Woodfield, William C. Hecker, Calvin H. Bartholomew, Morris D. Argyle Jan 2018

Effects Of Ag Promotion And Preparation Method On Cobalt Fischer- Tropsch Catalysts Supported On Silica-Modified Alumina, Mahmood Rahmati, Baiyu Huang, Landon M. Schofield, Thomas H. Fletcher, Brian F. Woodfield, William C. Hecker, Calvin H. Bartholomew, Morris D. Argyle

Faculty Publications

A series of silver-promoted, 20 wt% cobalt Fischer-Tropsch synthesis (FTS) catalysts supported on an alumina modified with 5 wt% silica were prepared using two methods: traditional incipient wetness impregnation (IWI) and a new solvent deficient precipitation (SDP) technique. Catalysts containing silver promoter concentrations of 0.3, 0.6, 1.2, and 2.5 wt% were prepared using each of the two methods. Silver improved the reducibility of the cobalt significantly, lowering reduction temperatures by up to 100 C, and increasing the extent of reduction by up to 35%. Further, in both preparation methods, changing the silver loading altered the cobalt dispersion. The smallest Co …


Lab-Scale Observations Of Flame Attachment On Slopes With Implications For Firefighter Safety Zones, Jonathan R. Gallacher, Brad Ripa, Bret W. Butler, Thomas H. Fletcher Jan 2018

Lab-Scale Observations Of Flame Attachment On Slopes With Implications For Firefighter Safety Zones, Jonathan R. Gallacher, Brad Ripa, Bret W. Butler, Thomas H. Fletcher

Faculty Publications

The Coanda effect is the phenomenon in which a jet entering quiescent fluid attaches to a nearby solid object due to inhibited entrainment of ambient fluid near the solid. Little is known about the influence of the Coanda effect on wildland fire behavior. Specifically, there is a lack of knowledge regarding how the flame attachment on slopes influences firefighter safety zone considerations in rugged terrain. This paper presents results for small-scale n-heptane pool fire experiments near a slope, showing how flame shape and heat flux are influenced by slope angle, slope boundary condition and distance from flame base. Flames near …


Effect Of Different Alumina Supports On Performance Of Cobalt Fischer-Tropsch Catalysts, Thomas H. Fletcher Jan 2018

Effect Of Different Alumina Supports On Performance Of Cobalt Fischer-Tropsch Catalysts, Thomas H. Fletcher

Faculty Publications

Four identically-prepared 20 wt% cobalt/0.15 wt% ruthenium Fischer-Tropsch catalysts, supported on different aluminas, were synthesized by incipient wetness impregnation, characterized, and compared based on their performance under standard Fischer-Tropsch synthesis conditions. Three alumina supports were obtained from commercial sources (Sasol, St. Gobain, and Alfa Aesar), while the fourth was made using a published technique that included 5 wt% silica. The silica-stabilized alumina catalyst produced superior Fischer-Tropsch rates of 49 mmol CO/gcat h, compared to the other catalysts on the commercial supports with rates of 26–39 mmol CO/gcat h. The improved performance of the silica-stabilized alumina support compared to the commercially …


Development Of Bioreactors For Comparative Study Of Naturalattenuation, Biostimulation, And Bioaugmentation Ofpetroleum-Hydrocarbon Contaminated Soil, Mohammad-Saeed Safdari, Hamid-Reza Kariminia, Mahmood Rahmati, Farhad Fazlollahi, Alexandra Polasko, Shaily Mahendra, W Vincent Wilding, Thomas H. Fletcher Jan 2018

Development Of Bioreactors For Comparative Study Of Naturalattenuation, Biostimulation, And Bioaugmentation Ofpetroleum-Hydrocarbon Contaminated Soil, Mohammad-Saeed Safdari, Hamid-Reza Kariminia, Mahmood Rahmati, Farhad Fazlollahi, Alexandra Polasko, Shaily Mahendra, W Vincent Wilding, Thomas H. Fletcher

Faculty Publications

Bioremediation of soil and groundwater sites contaminated by petroleum hydrocarbons is known as a technically viable, cost-effective, and environmentally sustainable technology. The purpose of this study is to investigate laboratory-scale bioremediation of petroleum-hydrocarbon contaminated soil through development of eight bioreactors, two bioreactors for each bioremediation mode. The modes were: (1)natural attenuation (NA); (2) biostimulation (BS) with oxygen and nutrients; (3) bioaugmentation (BA)with hydrocarbon degrading isolates; (4) a combination of biostimulation and bioaugmentation (BS-BA). Total petroleum hydrocarbons (TPH) mass balance over the bioreactors showed about 2% of initial20,000 mg kg-soil−1TPH was removed by advection due to synthetic groundwater which was flow-ing …


A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part I: Model Derivation, David W. Mead, Saman Monjezi, Joontaek Park Jan 2018

A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part I: Model Derivation, David W. Mead, Saman Monjezi, Joontaek Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new polydisperse "toy" constitutive model is derived and developed from fundamental principles and ideas governing the nonlinear rheology of linear flexible polymers [Mead et al., J. Rheol. 59, 335-363 (2015)]. Specifically, the new model is comprised of four fundamental pieces. First, the model contains a simple differential description of the entanglement dynamics of discrete entanglement pairs. Second, the model contains a differential description of the ij entanglement pair orientation tensor dynamics. Third, following a similar development by Mead and Mishler [J. Non-Newtonian Fluid Mech. 197, 61-79 and 80-90 (2013).], a diluted stretch tube is constructed to describe the relative …


A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part Ii. Modeling "Shear Modification" Following Cessation Of Fast Shear Flows, David W. Mead, Saman Monjezi, Joontaek Park Jan 2018

A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part Ii. Modeling "Shear Modification" Following Cessation Of Fast Shear Flows, David W. Mead, Saman Monjezi, Joontaek Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

The polydisperse Mead-Park (MP) "toy" molecular constitutive model developed in Paper I [Mead et al., J. Rheol. 62, 121-134 (2017)] as well as our previously published work [e.g., J. Rheol. 59, 335-363 (2015)] is used in the "forward" direction to study model polydisperse melts of entangled linear flexible polymers in severe, fast shear flows. The properties of our new model are elucidated by way of numerical simulation of a representative model polydisperse polymer melt in step shear rate and interrupted shear flow. In particular, we demonstrate how the MP model simulates the individual molecular weight distribution (MWD) component dynamics as …


Face Size Biases Emotion Judgment Through Eye Movement, Shuo Wang Jan 2018

Face Size Biases Emotion Judgment Through Eye Movement, Shuo Wang

Faculty & Staff Scholarship

Faces are the most commonly used stimuli to study emotions. Researchers often manipulate the emotion contents and facial features to study emotion judgment, but rarely manipulate low-level stimulus features such as face sizes. Here, I investigated whether a mere difference in face size would cause differences in emotion judgment. Subjects discriminated emotions in fear-happy morphed faces. When subjects viewed larger faces, they had an increased judgment of fear and showed a higher specificity in emotion judgment, compared to when they viewed smaller faces. Concurrent high-resolution eye tracking further provided mechanistic insights: subjects had more fixations onto the eyes when they …


Formation Of Deposits From Heavy Fuel Oil Ash In An Accelerated Deposition Facility At Temperatures Up To 1219 °C, Robert Laycock, Thomas H. Fletcher Jan 2018

Formation Of Deposits From Heavy Fuel Oil Ash In An Accelerated Deposition Facility At Temperatures Up To 1219 °C, Robert Laycock, Thomas H. Fletcher

Faculty Publications

Some industrial gas turbines are currently being fired using heavy fuel oil, which contains a small percentage of inorganic material that can lead to fouling and corrosion of turbine components. Deposits of heavy fuel oil ash were created in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University under gas turbine-related conditions. Ash was produced by burning heavy fuel oil in a downward-fired combustor and collecting the ash from the exhaust stream. This ash was then introduced into the TADF and entrained in a hot gas flow that varied from 1101 °C to 1219 °C. Sulfur dioxide was introduced …


Enhancement Of Heat Transfer Coefficient Using Nanofluids For Multi-Stage Flash Desalination (Msf) Plant, Nasser Zouli Jan 2018

Enhancement Of Heat Transfer Coefficient Using Nanofluids For Multi-Stage Flash Desalination (Msf) Plant, Nasser Zouli

Doctoral Dissertations

“The enhancement of thermal conductivity and local heat transfer coefficient, under laminar and turbulent flow regimes, of water-based spherical Al2O3, CuO, and Fe2O3 nanofluids have been experimentally investigated for the improvement of the thermal desalination processes using a newly developed sophisticated noninvasive heat transfer coefficient probe that is flush mounted on the inner wall surface of the test section. The nanoparticles have been selected because of their superior thermal conductivity and low cost, as well as the magnetic characteristic of Fe2O3 nanoparticle since a magnet can collect it and reuse. …


Reduced Exhaust Emissions Through Blending N-Butanol With Ultra Low Sulfur Diesel And Synthetic Paraffinic Kerosene In Reactivity Controlled Compression Ignition Combustion, Remi Gaubert Jan 2018

Reduced Exhaust Emissions Through Blending N-Butanol With Ultra Low Sulfur Diesel And Synthetic Paraffinic Kerosene In Reactivity Controlled Compression Ignition Combustion, Remi Gaubert

College of Graduate Studies: Theses & Dissertations

Increasing restrictions on the emitted exhaust emissions in diesel engines are becoming a more challenging task than in previous years. An electronic common rail fuel injection system and a port fuel injection (PFI) system were developed for an experimental engine to research dual fuel combustion. The experimental research was conducted at 1500 rpm and 4, 5, and 6 bar indicated mean effective pressure (IMEP). n-Butanol was port fuel injected at a 60% by mass fraction coupled with direct injection (DI) of three fuels, including ultra-low sulfur diesel (ULSD RCCI), a 50-50 wt-% blend of ULSD and butanol (ULSD-Bu RCCI), and …


Synthesis And Comprehensive Studies Of Nanogels For Enhanced Oil Recovery, Jiaming Geng Jan 2018

Synthesis And Comprehensive Studies Of Nanogels For Enhanced Oil Recovery, Jiaming Geng

Doctoral Dissertations

“Nanomaterials have been developed and applied for enhanced oil recovery (EOR) in oil industry. Among the developed nanomaterials, nano-sized crosslinked polymeric gel particles (nanogels) have shown the potential in improving both the macro- and micro-displacing efficiency. This dissertation focuses on the synthesis and the potential EOR mechanisms of nanogels. Nanogels with positive, negative, and neutral charges were synthesized through suspension polymerization. The morphology, size distribution, and zeta potential of nanogels were elucidated by corresponding technologies, such as scanning electron microscopy and dynamic light scattering. The ability of nanogels in oil-water interfacial tension (IFT) reduction and oil-in-water (o/w) emulsion stabilization was …


Comprehensive Evaluation Of A Novel Eor Method-Coupling Low Salinity Water Flooding And Preformed Particle Gel To Enhance Oil Recovery In Fractured Reservoirs, Ali K. Alhuraishawy Jan 2018

Comprehensive Evaluation Of A Novel Eor Method-Coupling Low Salinity Water Flooding And Preformed Particle Gel To Enhance Oil Recovery In Fractured Reservoirs, Ali K. Alhuraishawy

Doctoral Dissertations

"Excess water production in oil fields is becoming a challenging economic and environmental problem as more reservoirs are maturing. Water channeling, one of the primary reservoir conformance problems, is caused by reservoir heterogeneities that lead to the development of high-permeability streaks. The recovery of oil from carbonate reservoirs is usually low due to their extreme heterogeneity caused by natural fractures and the nature of oil-wet matrix. Also, oil recovery from fractured sandstone reservoirs is often low due to areal heterogeneity. Gel treatments have proven to be a successful and inexpensive fluid diversion method when used to plug the thief zones …