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Full-Text Articles in Physical Sciences and Mathematics
Experimental And Computational Techniques In Carbon-13 Nmr, Samuel John Varner
Experimental And Computational Techniques In Carbon-13 Nmr, Samuel John Varner
Dissertations, Theses, and Masters Projects
An efficient method for calculating NMR lineshapes from anisotropic second rank tensor interactions is presented. The algorithm produces lineshapes from asymmetric tensors by summing those from symmetric tensors. This approach significantly reduces the calculation time, greatly facilitating iterative nonlinear least squares fitting of experimental spectra. This algorithm has been modified to produce partially relaxed lineshapes and spectra of partially ordered samples.;Calculations for rapidly spinning samples show that spin-lattice relaxation time ( T1Z ) anisotropy varies with the angle between the spinning axis and the external field. When the rate of molecular motion is in the extreme narrowing limit, measurement of …
Characterization Of The Physical Properties Of Iron Polyimide Nanocomposites, Russell A. Wincheski
Characterization Of The Physical Properties Of Iron Polyimide Nanocomposites, Russell A. Wincheski
Dissertations, Theses, and Masters Projects
The discovery of tunneling magneto-resistance has led to a great deal of interest in the study of ferromagnet-insulator-ferromagnet (FIF) systems due to potential sensor and magnetic storage applications. An analysis of the band structure of the 3d ferromagnets shows that the conduction electrons become spin polarized by the molecular field. The transmission coefficient of these electrons across a tunneling gap therefore depends upon the relative alignment of the molecular field between the two ferromagnets.;In this work the manufacture of such tunneling gaps through compression molding of powdered ferromagnetic iron with a high performance polyimide has been studied for the first …
Thermoelastic And Photoelastic Full-Field Stress Measurement, Deonna Faye Woolard
Thermoelastic And Photoelastic Full-Field Stress Measurement, Deonna Faye Woolard
Dissertations, Theses, and Masters Projects
Photoelasticity is an optical technique that measures the difference of the principal stresses plus the principal stress direction. A complementary technique is thermoelasticity which measures the sum of the principal stresses. Combining these two full-field, non-contact nondestructive evaluation techniques allows the individual stress components to be measured. One of the main difficulties in merging these two measurement systems is in identifying an appropriate surface coating. Thermoelasticity demands a highly emissive surface, while photoelasticity requires a thick, stress-birefringent, transparent coating with a retro-reflective backing. Two coatings have been identified that can be used for combined thermoelastic and photoelastic stress measurements: PMMA …