Engineering Commons^™

Investigation Of Thermophysical Properties Of Enhanced Molten Salt Nanofluids For Thermal Energy Storage (Tes) In Concentrated Solar Power (Csp) Systems, Joohyun Seo

Material Science and Engineering Dissertations

Concentrated solar power (CSP) technologies have a great economical and technical potential for energy production in future. Its incorporation with thermal energy storage (TES) overcomes one of the biggest challenges in most renewable energy technologies, the intermittency of energy supply by natural resources. TES with 15-hour storage capacity is already commercialized to operate a CSP plant for 24 hours a day. When the sunlight is concentrated by mirrors into a small focal point, a heat transfer fluid (HTF) transfers the collected heat to a turbine or an engine to produce electricity and any surplus heat to a TES unit for …

Development Of Plasma Functionalized Nano-Additives For Oils And Study Of Their Tribological Properties, Vinay Sharma

Material Science and Engineering Dissertations

Lubricants used in motor engines contain various chemical species to help enhance energy efficiency and provide increased longevity. Unfortunately, at the same time, these additives become a source of catalytic poisoning, thus increasing emissions from the tailpipe. With growing concern for the negative impacts of human activities on the environment, regulatory bodies for the automobile lubrication industry have set up strict guidelines for chemical compositions of their end products, including engine oils. This research work is a step towards development of a new class of lubricant additives, which are less harmful to the environment and, simultaneously, also reduce friction and …

Real-Time Atomistic Observation Of Structural Phase Transformations In Individual Hafnia Nanorods, Bethany M. Hudak, Sean W. Depner, Gregory R. Waetzig, Anjana Talapatra, Raymundo Arroyave, Sarbajit Banerjee, Beth S. Guiton

Chemistry Faculty Publications

High-temperature phases of hafnium dioxide have exceptionally high dielectric constants and large bandgaps, but quenching them to room temperature remains a challenge. Scaling the bulk form to nanocrystals, while successful in stabilizing the tetragonal phase of isomorphous ZrO₂, has produced nanorods with a twinned version of the room temperature monoclinic phase in HfO₂. Here we use in situ heating in a scanning transmission electron microscope to observe the transformation of an HfO₂ nanorod from monoclinic to tetragonal, with a transformation temperature suppressed by over 1000°C from bulk. When the nanorod is annealed, we observe with …

Controlled Synthesis And Utilization Of Metal And Oxide Hybrid Nanoparticles, Cameron Cowgur Crane

Graduate Theses and Dissertations

This dissertation reports the development of synthetic methods concerning rationally-designed, hybrid, and multifunctional nanomaterials. These methods are based on a wet chemical, solution phase approach that utilizes the knowledge of synthetic organic and inorganic chemistry to generate building blocks in solution for the growth of nanocrystals and hybrid nanostructures. This work builds on the prior knowledge of shape-controlled synthesis of noble metal nanocrystals and expands into the challenging realm of the more reactive first row transition metals. Specifically, a microemulsion sol-gel method was developed to synthesize Au-SiO2 dimers as precursors for the synthesis of segmented heterostructures of noble metals that …

Synthesis, Characterization, And Enhanced Magnetic Properties Of Iron Carbide Nanomaterials, Brent M. Williams

Theses and Dissertations

Permanent magnets are classified as hard magnetic materials with the main purpose of generating flux for applications such as electric motors, turbines, and hard drives. High coercivity, magnetic remanence, and saturation values with high stability are some of the requirements for permanent magnets. Rare-earth magnets including neodymium and samarium based magnets are known to have superior magnetic properties due to their high magnetocrystalline anisotropy. However, due to the price of rare-earth materials development of alternate permanent magnets composed of inexpensive materials is an ongoing process. Previously cobalt carbide (Co_xC) have shown promise as a potential rare-earth free magnet …

Synthesis Of Discrete Transition Metal (Ni, Fe, Co, Mn) Phosphide Nanoparticles: Compositional Effect On Catalytic And Magnetic Properties, Da Li

Wayne State University Dissertations

This dissertation research is focused on the synthesis, characterization of binary and ternary transition metal (Ni, Co, Fe, Mn) phosphide nanomaterials and their catalytic and magnetic properties.

A phase-control strategy enabling the arrested-precipitation synthesis of nanoparticles of Ni5P4 and NiP2 is presented. The composition and purity of the product can be tuned by changing key synthetic levers, including the metal precursor, the oleylamine (OAm) and Trioctylphosphine (TOP) concentrations, temperature, time and the presence or absence of a moderate temperature soak step to facilitate formation of Ni and/or Ni-P amorphous nanoparticle intermediates.

New CoxFe2-xP nanoparticles (0 ≤ x ≤ 2), Co2-xMnxP …

Study Of Stability And Thermal Conductivity Of Nanoparticles In Propylene Glycol, Sumit Mahajan

All Graduate Theses, Dissertations, and Other Capstone Projects

This thesis studied the effects of gravity induced settling, thermophoresis and Brownian motion on the thermal conductivity of the Aluminum Oxide (Al2O3) nanofluids. The base fluid was propylene glycol. The effects were studied by making three samples with volumetric percentages of 0.2 %, 2% and 3% Al2O3 in propylene glycol. Sets of 22 experiments were conducted over time to understand the behavior of settling. All samples were manually mixed each time the experiment was conducted. A Thermtest Transient Plane Source TPS 500S was used to measure the thermal conductivity. Volumetric percentages and diameters of nanoparticle were chosen so that the …