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Full-Text Articles in Engineering
High Enthalpy Storage Thermoset Network With Giant Stress And Energy Output In Rubbery State And Associated Applications, Jizhou Fan
LSU Doctoral Dissertations
In this study, a new shape memory thermoset network with giant stress and energy output in rubbery state is synthesized and studied firstly since the low output in stress and energy in rubbery state has been a bottleneck for wide-spread applications of thermoset shape memory polymers (SMPs). Traditionally, stress or energy storage in thermoset network is through entropy reduction by mechanical deformation or programming. We here report another mechanism for energy storage, which stores energy primarily through enthalpy increase by stretched bonds during programming. As compared to entropy-driven counterparts, which usually have a stable recovery stress from tenths to several …
Design Of Natural Composite I-Beam For Sampe 2019, Brian Harkness
Design Of Natural Composite I-Beam For Sampe 2019, Brian Harkness
Honors Theses
In recent years, the demand for high performance, lightweight, fiber-reinforced composites have grown substantially. Fiberglass and carbon fiber have exemplary material properties that meet the demand and have set the industry standard for performance materials. Although these materials meet their design function, they suffer from high environmental impacts throughout their life cycle and are not cost effective to produce. Flax fiber composites have comparable properties to fiberglass but can be produced more efficiently and production requires much less energy consumption. Flax is a readily available, renewable material that will easily biodegrade once it is the end of its useful life …
Moisture Characterization Of Thermoplastics And Thermosets For Use As Matrices In Fiber Reinforced Composites, Kieran Hook, Ray Hsu
Moisture Characterization Of Thermoplastics And Thermosets For Use As Matrices In Fiber Reinforced Composites, Kieran Hook, Ray Hsu
Materials Engineering
Epoxy matrix composites are widely used in aerospace industry for lighter aircraft while thermoplastic-matrix composites have traditionally been underutilized despite their excellent fracture resistance, impact strength, and the ability to be recycled. Toray Advanced Composites (Morgan Hill, CA) wants to investigate the structural integrity of thermoplastic matrices in common aircraft operating environments. An experiment was conducted to observe the effect of moisture absorption on thermoplastic composites’ mechanical strength. PEEK, PPS, and PEI matrices were compared to an epoxy matrix in this experiment. Samples were submerged in 160ºF distilled water to accelerate moisture absorption. For two months, the changes in mass …
Synthesis And Characterization Of Dielectric And Multiferroic Nanocrystalline Transition Metal Oxide Materials And Nanocomposites, Frederick A. Pearsall
Synthesis And Characterization Of Dielectric And Multiferroic Nanocrystalline Transition Metal Oxide Materials And Nanocomposites, Frederick A. Pearsall
Dissertations, Theses, and Capstone Projects
Nanocrystalline transition metal oxides with unique chemical, physical, magnetic and dielectric properties have very broad applications, ranging from photocatalysis, capacitor energy storage and 4-state memory. Frequency stable, high permittivity nanocomposite capacitors produced under mild processing conditions offer an attractive replacement to MLCCs derived from conventional ceramic firing. In one project reported herein, 0-3 nanocomposites were prepared using BaTiO3 (barium titanate, BTO) nanocrystals, suspended in a poly(furfuryl alcohol) matrix, resulting in a stable, high effective permittivity, low and stable loss dielectric. Effective medium approximations were used to compare this with similar nanocomposite systems. The use of synthesized BTO nanocrystal photocatalysts …
Experimental Measurement Of Dielectric Properties Of Powdery Materials Using A Coaxial Transmission Line, Robert Tempke
Experimental Measurement Of Dielectric Properties Of Powdery Materials Using A Coaxial Transmission Line, Robert Tempke
Graduate Theses, Dissertations, and Problem Reports
This study proposes a standard methodology for coaxial dielectric property measurements of powdery materials (1-10GHz) using a coaxial transmission line. Four powdery materials with dielectric constants ranging from 3.5 to 70 (SiO2, Al2O3, CeO2, and TiO2) were experimentally investigated at varying volume loading fractions in a paraffin mixture. A statistically significant number of paraffin heterogeneous-mixtures was synthesized for all dielectric powders. The dielectric properties of the constitutive materials were determined using appropriate mixture equations. The sensitivity of the equations dielectric prediction to volume loading is discussed with guidance on selecting the best mixing equation. It was determined that low volume …