Thermodynamics Commons^™

Investigation Of Asphaltene Adsorption At Liquid-Liquid And Liquid-Solid Interfaces, Fang Liu

Dissertations and Theses

Asphaltenes, as indigenous components in crude oils, are believed to play an important role in the petroleum production and processing industry. For example, asphaltene molecules can adsorb onto the water / oil interface like the amphiphiles and hinder water droplet coalescence, resulting in the stabilization of water-in-oil emulsions. Also, in the upstream production, depending on the temperature and pressure, asphaltenes can precipitate and deposit onto the reservoir rocks, the wellbores and the pipelines, leading to the change in reservoir rocks’ surface wettability and the blockage of the production facilities. Hence, it is crucial to understand the mechanism of asphaltenes adsorption …

Capillary Forces And Wetting Dynamics By Diffuse-Interface Modeling, Fanny Thomas

Dissertations and Theses

Wetting phenomena underlie many natural and industrial processes, from the proper functioning of the lungs to the thin coating of surfaces. The three-phase interactions involved at microscopic scales play a critical role. Adding solid particles to an emulsion, for example, can drastically change the flow behavior due to capillary bridging between the particles. The study of these three-phase systems is especially relevant to the petroleum industry, where gas hydrates forming large clusters in subsea pipelines during crude oil transportation is a major concern. The dynamics of such systems is also of great interest from a fundamental perspective. Indeed describing non-equilibrium …

Process Development Of Shale Gas Assisted Lignin And Biomass Reforming Through Novel Reaction Pathway And Catalyst Design To Produce Hydrogen Rich Syngas For Fuels And Value Added Chemicals, Amoolya D. Lalsare

Graduate Theses, Dissertations, and Problem Reports (ETD)

Novel biomass reforming strategy through synergistic co-processing with flare gas (methane and carbon dioxide) was developed at West Virginia University. Hardwood biomass comprised of lignin, hemicellulose, and cellulose is abundant in the US and potentially a sustainable source of hydrogen through extensive reforming and gasification. Ever-increasing shale gas production in the US occasionally leads to flaring owing to stranded production across the US. Achieving biomass co-processing with natural gas about to be flared in such stranded shale plays is the underlying motivation here. A novel reaction pathway was discovered wherein methane and carbon dioxide assisted reforming of biomass could be …

Process Modeling And Techno-Economic Analysis Of Thermo-Catalytic Dimethyl Ether Synthesis And Microwave-Based Aromatics Production Technologies From Shale Gas, Chirag Mevawala

Graduate Theses, Dissertations, and Problem Reports (ETD)

Production of dimethyl ether (DME) and direct non-oxidative methane dehydroaromatization (DHA) to aromatics via conventional and microwave (MW)-assisted processes are investigated in this research. Plant-wide models of the shale gas to DME process with integrated CO₂ capture via direct and indirect synthesis routes have been developed. Optimal parameter estimation, and model validation are undertaken for various sections of the process including the pre-reforming reactor, auto-thermal reforming reactor, DME synthesis reactors, CO₂ capture units and separation sections. A novel DME separation process has been developed for efficient separation of DME, syngas, and CO₂. Plant-wide techno-economic optimization is …

Experimental And Computational Characterization Of Sodium Nitrate @ Silica Nano Capsules For Thermal Energy Storage Applications, Wataru Hashimoto

Graduate Research Theses & Dissertations

In this investigation, a nanocapsule composed of a sodium nitrate core and a silicon dioxide shell is synthesized, characterized, and analyzed utilizing a mixture of analytical and computational tools. The sol-gel method was selected as the process of nanoencapsulation. Analytical characterization techniques employed in this investigation include differential scanning calorimetry (DSC) to measure melting temperatures and enthalpies of fusion, dynamic light scattering (DLS) to calculate particle size distributions, scanning electron microscopy (SEM) to analyze surface characteristics, transmission electron microscopy (TEM) to perform shell characterization, and energy dispersive X-ray spectroscopy (EDS) to determine chemical composition. Preliminary results indicated a decrease in …

Thermal / Structural Analysis Of The Hb 650 Thermal Shield, Gerald J. Smith

Graduate Research Theses & Dissertations

Fermilab’s PIP-II project’s superconducting linear accelerator (Linac) will drive the next generation of particle accelerators through a revolution in beam intensity. Key to beam intensification are the high efficiencies of niobium-tin superconducting radiofrequency (SRF) cavities operating at cryogenic temperatures near 5 Kelvin. A multifaceted approach is employed to achieve and maintain the extreme temperature. Vacuum provides the first barrier to thermal convection. Physical thermal intercept zones further isolate the exterior shell vacuum vessel at 300 Kelvin from the supercooled beamline. The first thermal intercept lies just inside the exterior vacuum vessel forming the 40 Kelvin zone. This 40K thermal shield …

Customized Boron And Magnesium-Based Reactive Materials Prepared By High Energy Mechanical Milling, Xinhang Liu

Dissertations

New reactive materials need to be developed having biocidal combustion products. When ignited, such material can add chemical biocidal effects to the common effects of high temperature and pressure. Biocidal combustion products are capable of deactivating harmful spores or bacteria, which can be released by targets containing biological weapons of mass destruction. Research showed that halogens, especially iodine, are effective as biocidal components of reactive material formulations. Recently, magnesium combustion product MgO is also found to have a biocidal effect. Thus, advanced formulations containing both magnesium and iodine are of interest; such formulations are prepared and investigated here.

Reactive materials …

The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1

Tanzania Journal of Engineering and Technology (TJET)

Worldwide, every day human beings generate millions of tons of Faecal Sludge (FS), which is rich in water, nutrients, energy, and organic compounds. Yet FS is not being managed in a way that permits us to derive value from its reuse, while at the same time, millions of farmers struggle with depleted soils and lack of water. In most of the developing countries, energy for cooking is mainly derived from cutting of trees, either as wood or charcoal. Resource recovery and reuse from FS can create livelihoods, enhance food security, support green economies, reduce waste and contribute to cost recovery …

Coulombic And Non-Coulombic Effects Of Single And Overlapping Electric Double Layers With Surface Charge Regulation, Raviteja Vangara

Chemical and Biological Engineering ETDs

The physical origin of charged interfaces involving electrolyte solutions is in the thermodynamic equilibrium between the surface reactive groups and certain dissolved ionic species in the bulk. This equilibrium is very strongly dependent on the precise local density of these species, also known as potential determining ions in the solution. The latter, however, is determined by the overall solution structure, which is dominated by the large number of solvent molecules relative to all solutes. Hence, the solvent contribution to the molecular structure is a crucial factor that determines the properties of electric double layers. Models that explicitly account for the …

Performance Modeling Of Supercritical Carbon Dioxide Zigzag-Channel Printed Circuit Heat Exchangers, Katrine Birgitte Bennett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Supercritical carbon dioxide (sCO2) is currently being studied as the working fluid in power producing Brayton cycles due to its excellent physical and thermodynamic properties, especially near the critical point. Printed circuit heat exchangers (PCHEs) are being considered for use as condensers and recuperators for this purpose due to their high strength and compact designs. Many experimental and numerical studies are being conducted to characterize and optimize sCO2 PCHE operation and develop correlations to describe their thermal-hydraulic performance. Additionally, a few experimental and numerical structural assessments of these PCHEs have been conducted, but all have been somewhat limited due to …

Cfd Simulation Investigating The Effects Of Groove Geometry On Heat Transfer For Internally Grooved Tubes, Richard Zaven Saroukhanoff

UNLV Theses, Dissertations, Professional Papers, and Capstones

This numerical study investigates the thermal performance of internally grooved tubes used in heat exchangers. In order to enhance the performance of heat exchangers, turbulence promoters are inserted along the streamwise flow. The use of inserts, grooves, and augmentations along the axial length of the tube creates disturbances that improve the overall heat transfer due to enhanced fluid mixing and greater surface contact boundary walls. However, the implementation of tube wall augmentations creates an increase in pressure drop across the tube which must be compensated for with additional pumping power for the working fluid. Therefore, in order to analyze the …

An Investigation Of The Chemistry, Thermodynamics And Catalytic Activity Of Molybdenum Carbides, Shanti Kiran Nayak

Chemical and Biological Engineering ETDs

These studies investigate the chemistry and stability of molybdenum carbides as an electrocatalyst. Due to their unique electronic properties, molybdenum carbides are purposed as electrocatalysts for reaction systems such as hydrogen evolution reaction, bifunctional water splitting and CO oxidation.

In this study, various synthesis processes were utilized to produce different types of molybdenum carbide with varying properties of particle size, surface area and excess carbon. The samples characterized by XRD accompanied by Whole Profile Fitting, Electron Microscopy, Gas Adsorption (surface area) and XPS.

These synthesis processes were refined using fundamental thermodynamic analyses. These analyses highlight regions of stability of different …

Theoretical Investigations Of The Electronic, Magnetic, And Thermoelectric Properties Of Transition-Metal Based Compounds, Haleoot Edaan Raad

Graduate Theses and Dissertations

The electronic, magnetic, and thermoelectric properties of transition-metal based compounds were investigated by using the density functional theory and Boltzmann transport formalism. It was found that the Co-based Heusler compounds and InSe monochalcogenide are among the materials that may be used for future thermoelectric devices. Furthermore, the investigation showed that the quaternary Heusler compounds, such as, CoFeYGe, where Y is Ti or Cr, are half-metallic ferromagnetic materials with full electron spin polarization. The lattice thermal conductivity (κL) was found to decrease for these alloys as the temperature increases. The present investigation indicated that the phonon optical modes have a major …

A Kinetic And Thermodynamic Model Of Ethylene Dichloride Pyrolysis., Travis J Czechorski

Electronic Theses and Dissertations

Ethylene dichloride (EDC) is a precursor for the production of vinyl chloride (VCM) which is subsequently polymerized to form polyvinyl chloride (PVC). To convert EDC to VCM, EDC undergoes a pyrolysis process in the absence of oxygen at temperatures exceeding 500C. However, process yields are limited by the uncontrolled production of side-products that can degrade the quality of PVC and poison the reactor. Thus, tight process controls and costly separations guided by heuristics and plant operator experience are used to optimize EDC pyrolysis. To improve the process, I have programed a kinetic model of EDC pyrolysis based upon estimations of …

Fabrication Of Polyvinylidene Fluoride Hollow Fiber Membranes For Membrane Distillation, Abdullah Al Balushi

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Desalination technologies can help humanity tap into the most abundant source of water on earth, seawater; however, desalination is an energy-demanding process. Most of the desalination plants worldwide use conventional energy resources; therefore, desalination leaves a large carbon footprint. Solar energy is an available source of energy that can be harvested and integrated into desalination systems.

Membrane distillation (MD) is an emerging purification technology that many offers many advantages over traditional desalination systems. For starters, it can utilize low-grade thermal energy to drive the separation, therefore, it can be suitably integrated into the solar-thermal energy scheme. Additionally, MD can be …

Energy Transformation And Conservation Investigation, Mike Jackson, Holly Haney

High School Lesson Plans

Students will use a thermoelectric generator module to analyze the relationship between thermal and electrical energies. Using data collection sensors and analysis software, students will investigate the relationship between the temperature gradient across a thermoelectric generator module and the resulting electrical potential. Students will then use their data and analysis to solve problems relating to waste thermal energy in electrical systems and communicate their work to their peers and teacher.

Influence Of Tempering And Cryogenic Treatment On Retained Austenite And Residual Stresses In Carbonitrided 18crnimo7-6 Low Alloy Steel, Richard Katemi

Tanzania Journal of Engineering and Technology (TJET)

This work investigated the influence of tempering conditions coupled with cryogenic treatment on thermal stabilization of retained austenite and residual stress distributions in carbonitrided 18CrNiMo76 low alloy steel samples. The carbonitriding conditions were set to enable attaining surface carbon and nitrogen content of 0.87 and 0.34 mass.-percent respectively. After carbonitriding, some of the samples were subjected to varying tempering conditions followed by cryogenic treatment at-120 °C using nitrogen gas. Analysis of both retained austenite and residual stresses was conducted using X-ray diffraction. In the as-quenched state, carbonitrided samples contained 52 mass.-percent. Samples that were directly subjected to the cryogenic treatment …

Highly Effective Geni Alloy Contact Diffusion Barrier For Bisbte Long-Term Thermal Exposure, Erdong Song, Brian S. Swartzentruber, Chowdary R. Koripella, Julio A. Martinez

Publications and Research

A GeNi alloy diffusion barrier for contacts on bismuth antimony telluride is proposed. Multiple gold contact diffusion barriers were tested at different thermal aging conditions in air and reducing atmospheres. Among all diffusion barriers, the GeNi alloy barrier shows the best performance for bulk samples with no substantial degradation of the contact resistance, no contact color change, and no change of thermoelectric properties. We observed DAu−GeNi = (9.8 ± 2.7) × 10−20 m2/s within the GeNi alloy barrier, which is 4 times smaller than DAu−BiSbTe. The presence of the initial Ge layer also proves to be effective in reducing nickel …

Desalination: Freeze Crystallization, Ibrahim Guiga

Chemical Engineering Undergraduate Honors Theses

The Freezerbacks researched, designed, and economically evaluated a full-scale freeze crystallization process as well as two alternative full-scale processes: 5 stage multiple effect evaporation and reverse osmosis. All three processes were designed to treat hyper-saline mine water that was sent into evaporation pond systems. These systems were designed for Freeport-McMoRan’s mines that need to treat impacted water.

The Freeport-McMoRan copper mine in Miami, Arizona was visited in order to gain insight about the problem. The mine is no longer actively mining copper and is in the process of reclaiming land used. An essential part of restoring the land is treating …

Self-Assembled Nanoantenna Enhance Optical Activity And Transport In Scalable Thin Films And Interfaces, Keith Richard Berry Jr.

Graduate Theses and Dissertations

Continued population growth and the decrease of existing energy platforms demands long-term solutions for development and implementation of scalable plasmonic metamaterials for energy and agricultural applications. Self-assembled nanoantenna into random and ordered arrangements are advanced herein for optical and thermal enhancements in scalable thin film. An analytical approach to estimating the thermal dynamics of random arrangements of nanoantenna resulted in estimates within 30% across a range of geometric parameters, nanoantenna-containing media, and thermal parameters. Multimodal thermal dynamics of polymer thin films containing gold nanoparticles (AuNPs) were observed through the natural log of the dimensionless temperature driving force plotted versus time …

Numerical Study Of Spacer Grid Geometry In A 5 X 5 Nuclear Fuel Rod Bundle, Wan Chuan Fan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Reactor fuel rod bundles serve as the primary heat source in light water reactors (LWRs), commonly found in the aforementioned PWR plants. The fuel rod bundles’ structure consists of a collection of fuel rods put into a parallel grid configuration. The bundles also include fuel rod spacers, which hold the fuel rods in place, in accordance with the grid. Repeating structures of the fuel bundles create the meta-structure in the reactor. In other words, the grid configuration repeats until it fills the entire space of the reactor. This results in reactor fuel rods suspended in the working fluid domain, oriented …

Scaling Film Cooling Adiabatic Effectiveness With Mass Transfer And Thermal Experimental Techniques, Luke J. Mcnamara

Theses and Dissertations

With increasing engine temperatures, it is becoming more important to design effective film cooling schemes. Low temperature, large scale tests are often implemented in the design process to reduce cost and complexity. A nondimensional adiabatic effectiveness can be used as an indication of the performance of a film cooling scheme. However, the coolant flow rate must be properly scaled between the low temperature tests and engine temperatures to accurately predict film cooling effectiveness. This process is complicated by gas property variation with temperature. Tests are commonly conducted using thermal measurement techniques with infrared thermography (IR), but the use of pressure …

Examination Of Flow Dynamics And Passive Cooling In An Ultra Compact Combustor, Tylor C. Rathsack

Theses and Dissertations

The Ultra Compact Combustor (UCC) promises to greatly reduce the size of a gas turbine engine’s combustor by altering the manner in which fuel is burnt. Differing from the common axial flow combustor, the UCC utilizes a rotating flow, coaxial to the engine’s primary axis, in an outboard circumferential cavity as the primary combustion zone. The present study investigates two key UCC facets required to further this combustor design. The first area of investigation is cooling of the Hybrid Guide Vane (HGV). This UCC specific hardware acts as a combustor center body that alters the exit flow angle and acts …

Tactical Missile Performance For Single And Multi-Wire Embedded Propellant Configurations With Discontinuities, Paul B. Wilson

Theses and Dissertations

This research analyzes the performance of a nominal air-to-air tactical missile with varying configurations of wire-embedded end-burning solid propellant grains. Single and multi-wire models are developed to determine if total impulse and range is improved. Discontinuities in the wires are simulated to determine if gaps in the wire will affect overall performance. Five wire materials, seven wire diameters, and nine different break locations are tested. This research demonstrates wire discontinuities have negligible impact on performance and carbon nanotube fibers can theoretically improve total impulse by up to 25% compared to radially burning boost-phase grains while providing similar thrust outputs.

Introducing Concept Maps In Undergraduate Thermodynamics, Jessie Lofton

ASEE IL-IN Section Conference

Concept maps, also called mind maps, are a widely utilized educational tool. While numerous studies cite the benefits of concept mapping as a tool for student learning, the use of concept maps is more common in non-engineering disciplines. This study examines student perceptions and academic performance in an undergraduate, introductory Thermodynamics course for students majoring in Mechanical Engineering. The pedagogical approach includes incorporating student-developed concept maps, as well as an interactive study tool for First Law analysis. Qualitative and quantitative results are presented. Results are limited to a single institution and a small sample size of students. Future work will …

Effects Of Hofmeister Ions On Transition Temperature Of Two Thermo-Responsive Polymers, Joshua Moser

Williams Honors College, Honors Research Projects

It was hypothesized that through the use of Hofmeister Ions, the lower critical solution temperature (LCST) of poly(vinyl methyl ether) (PVME) and poly(ethylene glycol)- poly(N-isopropylacrylamide) (PEG-b-pNIPAAm) block-copolymer could be controlled. Through literature searches and small lab experiments, our team found that there may be a connection between Hofmeister effects and phase transition of a thermo-responsive polymer. To try and prove this, the lab team decided to take four cations (Mg²⁺,Na⁺, Cs⁺, K⁺) in solution with the thermo-responsive polymers and compared their LCST to solutions of the thermo-responsive polymer in de-ionized …

Form Stable Phase-Change Materials, Russell Dent, Marjan Kashfipour, Nitin Mehra, Jiahua Zhu

Williams Honors College, Honors Research Projects

This work investigates the use of two different polyols, xylitol (Xyl) and erythritol (Ery), in conjunction with boron nitride (BN) aerogels, for the purpose of creating thermally conductive composites. While the BN filler in Xyl composites achieved a high anisotropic thermal conductivity of up to 4.53 W/m-K at 18.2 weight percent filler loading, they do not exhibit good phase-change material qualities due to a low solidification enthalpy even at low cooling rates. Alternatively, the BN-Ery composites have shown promising results with a solidification enthalpy of 225.14 J/g and a melting enthalpy of 385.84 J/g at a heat rate of 5 …

Empirical Modeling Of Urea Synthesis Chemical Equilibria, Moustafa A. Soliman

Chemical Engineering

In this paper empirical formulas for the chemical equilibrium of reactions involved in urea synthesis are derived. Their accuracy is checked against data obtained from the application of Aspen Plus to a urea plant based on Stamicarbon technology. The accurate results obtained support their application in the simulation of the reactions involved in urea synthesis.

Thermal Analysis And Design Of Conduction Links For A Superconducting Radio Frequency Resonator, Aaron Mckeown

Graduate Research Theses & Dissertations

The SRF conduction link project at Fermi National Accelerator Laboratory aims to develop an SRF particle accelerator design that is more applicable for industrial use. Collaboration between NIU college of engineering and NIU department of physics provided the bulk of design and analysis for this project. Currently, cooling systems, used in SRF particle accelerators, pump liquid helium across the SRF cavity to provide convection based cooling. The goal of this project is to incorporate a conduction based cooling system. In a conduction based cooling system, heat will flow from the SRF cavity into a cryocooler through a conduction link. In …

Experimental Investigation Of Liquid Contact In The Developing Post-Dryout Chf Flow Boiling Regime Using Surface Mounted Thermistors, Hiralkumar Harshadbhai Patel

Doctoral Dissertations

"Understanding heat transfer in the post-critical heat flux (CHF) flow boiling regime is important for determining the performance of the heat transfer equipment for various industrial applications requiring high heat transfer rates, e.g., heat exchangers, boilers, chemical and nuclear reactors. Liquid can be present in the core of the flow channel in the form of entrained liquid droplets, especially immediately downstream of film dryout. These droplets are suspected to provide an important heat transfer mechanism as they impinge on the heated wall. The objective of the current study is to investigate liquid contact with the heated wall in this flow …