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Full-Text Articles in Mechanics of Materials

Fabrication, Thermophysical, And Mechanical Properties Of Cermet And Cercer Fuel Composites For Nuclear Thermal Propulsion, Neal D. Gaffin Dec 2022

Fabrication, Thermophysical, And Mechanical Properties Of Cermet And Cercer Fuel Composites For Nuclear Thermal Propulsion, Neal D. Gaffin

Doctoral Dissertations

Nuclear thermal propulsion (NTP) utilizes nuclear fission to double the efficiency of
in-space propulsion systems compared with traditional combustion rocket systems.
NTP systems are limited primarily by the fuel material choice, due to the extreme
conditions they will need to endure, including temperatures up to 3000 K, multiple
thermal cycles with rapid heating and cooling, exposure to hot flowing hydrogen,
large thermal gradients, and high neutron flux. Particle based fuels, namely ceramic-
metallic (cermet) and ceramic-ceramic (cercer) composites are both promising fuel
element material candidates for NTP. Given the high temperature nature, these
materials are difficult to fabricate and very …


Energy Selective Neutron Imaging For The Characterization Of Polycrystalline Materials, Robin Woracek May 2015

Energy Selective Neutron Imaging For The Characterization Of Polycrystalline Materials, Robin Woracek

Doctoral Dissertations

This multipart dissertation focuses on the development and evaluation of advanced methods for material testing and characterization using neutron diffraction and imaging techniques. A major focus is on exploiting diffraction contrast in energy selective neutron imaging (often referred to as Bragg edge imaging) for strain and phase mapping of crystalline materials. The dissertation also evaluates the use of neutron diffraction to study the effect of multi-axial loading, in particular the role of applying directly shear strains from the application of torsion. A portable tension-torsion-tomography loading system has been developed for in-situ measurements and integrated at major user facilities around the …


Single Fiber Mechanical Properties Using Nano-Tensile Testing And Carbon Fiber Structure-Property Relationship, Matthew Erich Kant Dec 2014

Single Fiber Mechanical Properties Using Nano-Tensile Testing And Carbon Fiber Structure-Property Relationship, Matthew Erich Kant

Doctoral Dissertations

Single carbon fibers are studied using a nano-tensile testing system. This system has unprecedented load and displacement resolution, nN and nm respectively, and the ability to perform dynamic testing for storage and loss modulus during quasi-static tensile extension. Furthermore, improved fiber mounting and alignment procedures coupled with the precision of the nano-tensile testing system assist in unprecedented resolution in single fiber mechanical testing for axial modulus and strength. Hence, using these unique capabilities, the moduli and their statistical distribution of many high performance carbon fibers are reported here. From this, a simplified single parameter model describing the strain dependent modulus …


Structural Analysis Of The Tablerock Thrust Sheet, Grandfather Mountain Window, Northwestern North Carolina: Emplacement Kinematics Of A Large Horse In A Major Thrust System, Ann Elizabeth Walker May 2014

Structural Analysis Of The Tablerock Thrust Sheet, Grandfather Mountain Window, Northwestern North Carolina: Emplacement Kinematics Of A Large Horse In A Major Thrust System, Ann Elizabeth Walker

Masters Theses

The Tablerock thrust sheet is exposed along the southwestern margin of Grandfather Mountain window in northwestern North Carolina, where it separates basement and cover rocks inside the window from basement thrust sheets of the overriding Blue Ridge-Piedmont megathrust sheet. It is a complex of footwall-derived horses of rifted-margin metasedimentary rocks, including Neoproterozoic to Early Cambrian Chilhowee Group quartzite and phyllite, and Shady Dolomite. Penetrative deformation throughout the Tablerock thrust sheet is defined by an extensively transposed foliation, and strong colinearity between well developed transport lineations and SE/NW-trending tight, isoclinal, and sheath folds. Centimeter- to meter-scale sheath folds are common throughout …


Effect Of Moisture Absorption On The Sinter Quality Of Central Solenoid (Cs) Coil Pack, Zeshaan Sher Mohammed Dec 2010

Effect Of Moisture Absorption On The Sinter Quality Of Central Solenoid (Cs) Coil Pack, Zeshaan Sher Mohammed

Masters Theses

Fusion energy has been said to be the solution to all the world’s energy problems. The International Thermonuclear Experimental Reactor (ITER) is the flagship project to demonstrate the feasibility of fusion energy. The Central Solenoid (CS), an important component of the reactor, is needed to induce plasma current, initiate, ramp-up, ramp-down, and sustain plasma in a very controlled manner. In order to achieve this, the CS coil packs must be manufactured under controlled conditions. The CS conductor is an advanced cable-in-conduit Nb3Sn superconductor. The CS cable will be made in long continuous sections but with thousands of meter of cable …