Thermodynamics Commons^™

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 …

Hydrothermal Preparation Of Palladium Supported On Magnetite For Catalysis Applications, Saddam Alaskary

Chemical Engineering

Herein, versatile, and reproducible method to prepare Pd/Fe3O4 via hydrothermal synthesis. The vital role of this catalyst is in its potential use in CO oxidation catalysis. The Pd/Fe3O4 shows a distinctive activity. TEM images confirmed that Pd nanoparticles of 8-12 nm have a well dispersion on the surface of magnetite (Fe3O4). Moreover, the prepared catalyst is recycled with remarkable catalytic activity. This outstanding activity is mainly a direct result of the strong metal-support interaction. The defect sites in the reduced iron oxide act as nucleation centers that enable anchoring of Pd nanoparticles leading to prevention of agglomeration.

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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.

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 …

Reduction Of Nox Emissions In A Single Cylinder Diesel Engine Using Sncr With In-Cylinder Injection Of Aqueous Urea, Anthony Timpanaro

UNF Graduate Theses and Dissertations

The subject of this study is the effect of in-cylinder selective non-catalytic reduction (SNCR) of NO_x emissions in diesel exhaust gas by means of direct injection of aqueous urea ((NH₂)₂CO) into the combustion chamber. A single cylinder diesel test engine was modified to accept an electronically controlled secondary common rail injection system to deliver the aqueous urea directly into the cylinder during engine operation.

Direct in-cylinder injection was chosen in order to ensure precise delivery of the reducing agent without the risk of any premature reactions taking place. Unlike direct in-cylinder injection of neat water, …

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 …