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Title: TM MODE SCATTERING BY A GLASS-ENCLOSED PLASMA CYLINDER.
Creator: QUINNELL, ROBERT DOUGLASS., Florida Atlantic University
Abstract/Description: Expressions are developed for the near and far field angular intensity distributions of TM mode scattering of a plane wave by a glass-enclosed plasma cylinder. Numerical computations for a simple collisionless plasma model are made in order to study the effect of the free electron density structure on intensity distributions. The inverse problem is briefly considered.
Date Issued: 1973
PURL: http://purl.flvc.org/fcla/dt/13560
Subject Headings: Scattering (Physics)
Format: Document (PDF)

Title: Cosmological studies with spatially homogenous models and quantum field effects in Kantowski-Sachs universe.
Creator: Sabir, Abdenour, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Perhaps constructing a complete theory of quantum gravity, has been one of the greatest challenges for theoretical physicists in the last few decades, a theory that would reconcile general relativity and quantum mechanics. Addressing this issue, we are drawing a parallel between the Schrodinger and Klein-Gordon equation in quantum mechanics and Schrodinger-based or Klein-Gordon based wave equation in canonical quantum gravity. In particular we analyze the quantum geometrodynamics Schrodinger...
Show morePerhaps constructing a complete theory of quantum gravity, has been one of the greatest challenges for theoretical physicists in the last few decades, a theory that would reconcile general relativity and quantum mechanics. Addressing this issue, we are drawing a parallel between the Schrodinger and Klein-Gordon equation in quantum mechanics and Schrodinger-based or Klein-Gordon based wave equation in canonical quantum gravity. In particular we analyze the quantum geometrodynamics Schrodinger equation for a homogeneous cosmological model and we study the quantum field effects for the &PHgr;6 scalar field in Kantowski-Sachs universe. In essence, we present a unified view of quantum gravity by establishing a parallel between our study and the usual quantum mechanics. Thus, the first part of this dissertation deals with the quantization of Bianchi type IX space-time where the concept of time is derived by imposing the constraints as expectation values over the true dynamical-degrees of freedom of the gravitational field. Thus, we obtained a Schrodinger type wave equation instead of the Wheeler-DeWitt which is associated with the problem of time in quantum gravity [1]. The main technical difference between our proposed equation and other quantum cosmology approaches is in our treatment of the constraints. Ordinarily, the equation cannot be solved simply by separating the coordinates variables, and only under some specific conditions imposed on the background that one may obtain exact analytical expressions. In the second part, we evaluated the one-loop renormalized effective potential for the massive self interacting &PHgr;6 theory the spatially homogenous and anisotropic Kantowki-Sachs Universe. We concluded that regularizing the theory in (3 + 1) dimensional space-time may not be possible. Finally, we looked at the time evolution of the critical temperature that is associated with our model.
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Date Issued: 2005
PURL: http://purl.flvc.org/fau/fd/FADT12125
Subject Headings: Physics, General
Format: Document (PDF)

Title: A New Mechanical and Radiation Isocenter Adjustment Approach Using the Isopoint.
Creator: Irons, Tristan, Kyriacou, Andreas, Florida Atlantic University, Department of Physics, Charles E. Schmidt College of Science
Abstract/Description: The Winston-Lutz has been the standard test for isocenter convergence, however, any adjustments needed – in case the test fails – are time consuming since the source of error is not readily available from the results. Isopoint by the Aktina Medical company has been developed to address this problem via decoupling the mechanical from the radiation isocenter and providing the user with information that was inaccessible before. The focus of this research is to perform optimization of the...
Show moreThe Winston-Lutz has been the standard test for isocenter convergence, however, any adjustments needed – in case the test fails – are time consuming since the source of error is not readily available from the results. Isopoint by the Aktina Medical company has been developed to address this problem via decoupling the mechanical from the radiation isocenter and providing the user with information that was inaccessible before. The focus of this research is to perform optimization of the isocenter by using the Isopoint and to confirm the validity of its results, as well as to find how much time is saved via this new technology. The data for this project was collected on a 2012 Elekta Synergy, a Varian 21ix, and a 2021 Elekta Versa through partnership with GenesisCare. Our findings indicate that the Isopoint will allow for more accurate and speedy adjustments of the LINAC (Linear Accelerator) and will be integral in the future of this field.
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Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014259
Subject Headings: Medical physics
Format: Document (PDF)

Title: Molecular dynamics study of atomic displacements in disordered solid alloys.
Creator: Puzyrev, Yevgeniy S., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The effects of atomic displacements on the energetics of alloys plays important role in the determining the properties of alloys. We studied the atomic displacements in disordered solid alloys using molecular dynamics and Monte-Carlo methods. The diffuse scattering of pure materials, copper, gold, nickel, and palladium was calculated. The experimental data for pure Cu was obtained from diffuse scattering intensity of synchrotron x-ray radiation. The comparison showed the advantages of...
Show moreThe effects of atomic displacements on the energetics of alloys plays important role in the determining the properties of alloys. We studied the atomic displacements in disordered solid alloys using molecular dynamics and Monte-Carlo methods. The diffuse scattering of pure materials, copper, gold, nickel, and palladium was calculated. The experimental data for pure Cu was obtained from diffuse scattering intensity of synchrotron x-ray radiation. The comparison showed the advantages of molecular dynamics method for calculating the atomic displacements in solid alloys. The individual nearest neighbor separations were calculated for Cu 50Au50 alloy and compared to the result of XAFS experiment. The molecular dynamics method provided theoretical predictions of nearest neighbor pair separations in other binary alloys, Cu-Pd and Cu-Al for wide range of the concentrations. We also experimentally recovered the diffuse scattering maps for the Cu47.3Au52.7 and Cu85.2Al14.8 alloy.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12137
Subject Headings: Physics, Condensed Matter, Physics, Atomic
Format: Document (PDF)

Title: The electronic structure of beta'-nickel-aluminum and its low-index, high-symmetry surfaces.
Creator: Hines, Eric Lawrence, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The electronic structure of beta'-NiAl alloy and its low-index high-symmetry surfaces has been studied with a combination of photocurrent and first-principles electronic structure calculations. Bulk calculations have been performed with both the LMTO and LSMS computational codes, and the core level shifts upon alloying are discussed in detail. Defect formation and bonding mechanisms in off-stoichiometric NiAl are investigated. The electronic structure of the (110), (100) and (111) surfaces...
Show moreThe electronic structure of beta'-NiAl alloy and its low-index high-symmetry surfaces has been studied with a combination of photocurrent and first-principles electronic structure calculations. Bulk calculations have been performed with both the LMTO and LSMS computational codes, and the core level shifts upon alloying are discussed in detail. Defect formation and bonding mechanisms in off-stoichiometric NiAl are investigated. The electronic structure of the (110), (100) and (111) surfaces are investigated using the LMTO and LSMS, and electronic potentials for input to the photocurrent code are evaluated in the surface geometry. Photocurrent calculations for the (110), (100) and (111) surface are presented and compared with high quality experimental measurements. The (100) surface is found to have a double Ni termination. This defect layer is predicted to sustain a magnetic moment. The rippling of the (110) surface is modelled in the photocurrent calculations, and is found to effect the spectral profile in significant ways. The calculated photocurrent spectra are used to predict the surface composition for the (100), (111) and (110) surfaces, and the rippling value of the (110) surface. Agreement with experiment is good. A method for utilizing computational photoemission spectra to predict the structure and composition of metallic surfaces is presented, and its strengths and weaknesses are discussed.
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Date Issued: 1996
PURL: http://purl.flvc.org/fcla/dt/12492
Subject Headings: Physics, Electricity and Magnetism, Physics, Condensed Matter
Format: Document (PDF)

Title: Atomic displacements in transition metals.
Creator: Moghadam, Nassrin Y., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Using the order-N locally-self-consistent multiple scattering (LSMS) method, we carry out first-principles studies of the displacement of atoms from their average sites in the vicinity of a vacancy and transition metal impurities in copper. Our approach is to relax the first nearest neighbor distance and to calculate total energy for a number of relaxed geometries. We then obtain the equilibrium configuration of the nuclei from minimization of the total energy.
Date Issued: 1998
PURL: http://purl.flvc.org/fcla/dt/12546
Subject Headings: Physics, Condensed Matter
Format: Document (PDF)

Title: Analysis of fluid instabilities in core collapse supernova progenitors by a semi-analytical methodology and by two dimensional radiation-hydrodynamical simulations.
Creator: Raley, Elizabeth Anne, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: We have performed an analysis of fluid instabilities below the neutrinospheres of the collapsed cores of supernova progenitors using a methodology introduced by Bruenn and Dineva [28, 29, 31]. In an extensive survey we found that the rate of lepton diffusion always exceeds the rate of thermal diffusion and as a result we do not anywhere see the neutron finger instability as described by the Livermore group [16, 17]. A new instability, lepto-entropy fingers, extending from a radius of 10--15...
Show moreWe have performed an analysis of fluid instabilities below the neutrinospheres of the collapsed cores of supernova progenitors using a methodology introduced by Bruenn and Dineva [28, 29, 31]. In an extensive survey we found that the rate of lepton diffusion always exceeds the rate of thermal diffusion and as a result we do not anywhere see the neutron finger instability as described by the Livermore group [16, 17]. A new instability, lepto-entropy fingers, extending from a radius of 10--15 km out to the vicinity of the neutrinosphere, driven by the cross-response functions (i.e. the dependence of lepton transport on entropy perturbations and vice versa) was discovered. This instability has a maximum growth rate of the order of 100 s-1 with a scale of approximately 1/20 the distance of a perturbed fluid element from the core center [18]. This instability has probably already been seen in some multi-dimensional core collapse calculations. To test our results predicting the presence of doubly diffusive instabilities below the neutrinosphere of a proto-supernova, we have performed two dimensional hydrodynamic simulations with radial ray neutrino transport. This entailed rewriting RadHyd, which is the merger of EVH-1 hydrodynamics and MGFLD neutrino transport developed by Bruenn and DiNisco [43], for two dimensions. In particular, hydrodynamic evolution along angular arrays was included, as was MPI message passing capabilities, in order to utilize massively parallel computer platform such as FAU's BOCA4 Beowulf cluster. This work was partially funded by a grant from the DOE Office of Science, Scientific Discovery through Advanced Computing Program.
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Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/12094
Subject Headings: Physics, Astronomy and Astrophysics
Format: Document (PDF)

Title: Osteometric analysis of intercostal variation and sexual dimorphism in the sternal end of the rib of modern American blacks.
Creator: Allen, Mary Barbot, Florida Atlantic University, Dorothy F. Schmidt College of Arts and Letters, Department of Anthropology
Abstract/Description: Research on the human rib has shown that the sternal end of this bone manifests differences in age, sex and race. It was also found that intercostal variation may affect the expression of these traits. The purpose of this study is to osteometrically analyze intercostal variation and sexual dimorphism in ribs 1-7 from a known sample of American black males (N = 110) and females (N = 52) collected from recent forensic autopsy cases. Results indicate that although intercostal variation is...
Show moreResearch on the human rib has shown that the sternal end of this bone manifests differences in age, sex and race. It was also found that intercostal variation may affect the expression of these traits. The purpose of this study is to osteometrically analyze intercostal variation and sexual dimorphism in ribs 1-7 from a known sample of American black males (N = 110) and females (N = 52) collected from recent forensic autopsy cases. Results indicate that although intercostal variation is significant, there is too much overlap to metrically determine rib position. Sexual dimorphism is sufficient to develop discriminant function formulae that separate males and females with a minimum accuracy of 75% (rib 1) and a maximum of 83% (rib 4). However, these functions are population and rib specific. This research confirms earlier findings on ribs 3-5, and expands the potential to determine sex from ribs 1-7.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15422
Subject Headings: Black Studies, Anthropology, Physical
Format: Document (PDF)

Title: Population Perspective in Osteology: A Case Study.
Creator: Lane, Rebecca A., Sublett, Audrey J., Florida Atlantic University, Dorothy F. Schmidt College of Arts and Letters, Department of Anthropology
Abstract/Description: Samples from two Southeastern populations classified as a "Koger's Island type" are re-examined using non-metrical osteological data. A populationist viewpoint is adopted and the data is analyzed statistically. This paper;diecusses the method and some problems inherent in its utilization. It is concluded that the two samples do not belong to the same breeding population. Anthropological implications of the method are briefly discussed.
Date Issued: 1969
PURL: http://purl.flvc.org/fau/fd/FA00012591
Subject Headings: Anthropometry, Physical anthropology
Format: Document (PDF)

Title: Photodegradation of 2-mercaptobenzothiazole disulfide and related benzothiazoles.
Creator: Zajickova, Zuzana, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: Benzothiazoles are heterocyclic compounds used predominantly as rubber vulcanization accelerators. The overall goal of our research was to investigate the photodegradation behavior of 2-mercaptobenzothiazole disulfide, its degradation product 2-mercaptobenzothiazole, and further degradation product benzothiazole. Modern analytical techniques were utilized to follow photodegradation process at arbitrary intervals. A chromatographic method using reverse phase liquid chromatography was developed...
Show moreBenzothiazoles are heterocyclic compounds used predominantly as rubber vulcanization accelerators. The overall goal of our research was to investigate the photodegradation behavior of 2-mercaptobenzothiazole disulfide, its degradation product 2-mercaptobenzothiazole, and further degradation product benzothiazole. Modern analytical techniques were utilized to follow photodegradation process at arbitrary intervals. A chromatographic method using reverse phase liquid chromatography was developed for the separation of benzothiazoles in the irradiated mixture. Direct photolysis of benzothiazole and 2-mercaptobenzothiazole in methanol at 253.7 and 313 nm in the presence or absence of oxygen was investigated at first. Benzothiazole was found to undergo photodimerization into 2,2'-bibenzothiazole, and in the presence of oxygen to give two additional photoproducts - 2-hydroxybenzothiazole and 2-methylbenzothiazole. The major degradation products of 2-mercaptobenzothiazole are benzothiazole and 2-benzothiazolesulfonic acid, with 2,2'-thiobisbenzothiazole, 2,x'-thiobisbenzothiazole (x = 4, 5, 6, 7), and 2-mercaptobenzothiazole disulfide as the minor degradation products. Direct photolysis of 2-mercaptobenzothiazole disulfide was investigated in four different solvents, at two different wavelengths (253.7 and 313 nm) and concentrations in the presence or absence of oxygen. In all cases 2-mercaptobenzothiazole and 2,x'-thiobisbenzothiazole were detected as the degradation products and in acetonitrile 2-thiocyanatobenzothiazole was also detected. A mechanism is proposed to rationalize the formation of photodegradation products. The effects of solvent, irradiation wavelength, and duration of irradiation time, concentration of the starting material and presence or absence of oxygen are summarized as well. It was observed that photodecomposition at 253.7 nm occurred at a much faster rate than at 313 nm and that less concentrated solutions decomposed faster. At higher concentration of 2-mercaptobenzothiazole its disulfide was detected as one of the degradation products. Methylated products were detected in methanol and acetonitrile and photoreaction took longer in polar protic solvents. Oxygenated products were formed in presence of oxygen and the photoreaction was slower as well in comparison to degassed solutions.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/12219
Subject Headings: Chemistry, Analytical, Chemistry, Physical
Format: Document (PDF)

Title: The electronic structure and properties of equi-atomic CuAu.
Creator: Xu, Xumou, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The electronic structure of equi-atomic CuAu has been investigated by a combination of photoelectron spectroscopy and first-principles band structure calculations. The study includes the first ever ARUPS and ARAES measurements from a single crystal of CuAu I. We have studied in detail the energy dispersion and shifts of a Tamm state on the (001) and (100) surfaces and we determined the surface lattice constants and the dependencies of the energy shifts on atomic concentration and geometry....
Show moreThe electronic structure of equi-atomic CuAu has been investigated by a combination of photoelectron spectroscopy and first-principles band structure calculations. The study includes the first ever ARUPS and ARAES measurements from a single crystal of CuAu I. We have studied in detail the energy dispersion and shifts of a Tamm state on the (001) and (100) surfaces and we determined the surface lattice constants and the dependencies of the energy shifts on atomic concentration and geometry. Two new surface states were found on the two surfaces and their properties have been investigated. Comparisons between the valence band spectra from the two samples of CuAu I have been carried out and the results show that the different atomic arrangements in the crystal do not have a significant effect on the band structure. We also compared spectra from the alloy with those from the parent metals. A series of calculations of the electronic structure of CuAu I has been carried out by the SCF-LMTO-ASA and RKKR methods. We found that the superzone boundaries that are created when the CuAu II phase is formed destroy appreciable regions of Fermi surface, thus, favoring the latter phase. The positions of the new boundaries are related directly to the period of the long period superlattice and we have investigated their dependence on the e/a ratio and pressure. The results are in very good agreement with previous experimental measurements. We also calculated the Fermi surfaces of three disordered Cu-Au alloys near the equi-atomic composition using the KKR-CPA scheme. The results have shown strong evidence that the Fermi surface topology may play an important role in stabilizing and determining the modulation of the LPS in CuAu II.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/12423
Subject Headings: Physics, Condensed Matter
Format: Document (PDF)

Title: The d(3,7) non-cubic ligand field spectrum and the electronic spectra of quadrate chromium (III) complexes.
Creator: Williams, Chamindra S., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: In the first-part of this two-part study, the quadrate energy levels of the d3 configuration including spin-orbit interaction are derived in the rare-earth coupling scheme using ligand-field symmetry parameters Dq, Ds, and Dt, by the method of tensor-operators. Comparison is made to the strong field coupling scheme. In the second part of this study, interpretation of polarised single-crystal spectra of trans-[Cr(tmd)2F2]ClO4, trans-[Cr(en)2(dma)2](ClO4) 3, trans-[Cr(en)2(dmf)Br](ClO4) 2 and...
Show moreIn the first-part of this two-part study, the quadrate energy levels of the d3 configuration including spin-orbit interaction are derived in the rare-earth coupling scheme using ligand-field symmetry parameters Dq, Ds, and Dt, by the method of tensor-operators. Comparison is made to the strong field coupling scheme. In the second part of this study, interpretation of polarised single-crystal spectra of trans-[Cr(tmd)2F2]ClO4, trans-[Cr(en)2(dma)2](ClO4) 3, trans-[Cr(en)2(dmf)Br](ClO4) 2 and trans-[Cr(en)2(dmf)Cl](ClO4) 2 as well as unpolarised single-crystal spectrum of trans-[Cr(en) 2(dmf)2](ClO4)3 and solution spectra of trans-[Cr(pn)(en)F2]ClO4, trans-[Cr(en)2FCl]ClO4 and trans-[Cr(en) 2FBr]ClO4 is made using Gaussian analysis of the bands in both polarisations where possible. Ligand field parameters Dq, Ds, Dt and B are extracted from the spectra using energy matrices in the strong-field coupling scheme by fitting the quadrate components of the two lowest energy cubic quartet bands exactly. Discussion of these parameters and the translated AOM (angular overlap model) parameters, is presented. A thorough interpretation of the high-energy intraconfigurational doublet bands in a number of trans-diacidobis (ethylenediamine) chromium (111) complexes is made using quadrate energy matrices including spin-orbit interaction. Entire programming code for the energy matrices in the rare-earth coupling scheme is included, as are procedures for computing 3-j and 6-j symbols. The complete quadrate energy matrices for d3 configuration in the strong-field coupling scheme with spin-orbit perturbation as well quadrate energy matrices for d3 configuration in the rare-earth coupling scheme are included.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12180
Subject Headings: Chemistry, Inorganic, Chemistry, Physical
Format: Document (PDF)

Title: MULTIDIMENSIONAL FORMULATION OF THE GENERAL RELATIVISTIC EQUATIONS OF MOTION.
Creator: BEYL, LAWRENCE MICHAEL., Florida Atlantic University, McGuire, James B.
Abstract/Description: A 4N-dimensional formalism is developed and a corresponding space is found. The necessity of coupling the particle's proper times to one parameter is discussed. The appropriate conditions and constraints which relate this space to the ordinary 4-space are found. The transformation properties which are consistent with general 4-space transformations are determined. These transformation properties are used to determine the form of the 4x4 matrices making up the 4N-dimensional metric tensor. The...
Show moreA 4N-dimensional formalism is developed and a corresponding space is found. The necessity of coupling the particle's proper times to one parameter is discussed. The appropriate conditions and constraints which relate this space to the ordinary 4-space are found. The transformation properties which are consistent with general 4-space transformations are determined. These transformation properties are used to determine the form of the 4x4 matrices making up the 4N-dimensional metric tensor. The form of these matrices indicates they represent interactions between particles. The diagonal matrices are shown to represent gravitational interaction and the off-diagonal matrices to represent other interparticle interactions. A metric theory to cover all interparticle interactions is then proposed. The equations of motion for one particle in this 4N-dimensional space are found. These equations are then related to the motion of N interacting particles in 4- space . Finally, an approximation procedure is applied to determine the first order equations of motion.
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Date Issued: 1974
PURL: http://purl.flvc.org/fcla/dt/13659
Subject Headings: General relativity (Physics), Motion
Format: Document (PDF)

Title: Magnetic, thermodynamic, and structural studies of manganese oxides.
Creator: Terashita, Hirotoshi, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Magnetic, thermodynamic, and structural properties of the manganese oxides La1-xCa xMnO3 are studied. Neutron powder diffraction reveals two distinct crystallographic phases as well as two magnetic (ferromagnetic and antiferromagnetic) phases for 0.08
Show moreMagnetic, thermodynamic, and structural properties of the manganese oxides La1-xCa xMnO3 are studied. Neutron powder diffraction reveals two distinct crystallographic phases as well as two magnetic (ferromagnetic and antiferromagnetic) phases for 0.08 < x < 0.14. Details of the compositional dependence of the phase fractions is discussed in the context of local ferromagnetism. Comparisons of magnetic and crystallographic properties are made to the analogous electron-doped Ca1- yLayMnO3 (0 < y < 0.20) system. Thermodynamic properties of La1- xCaxMnO 3 (0 < x < 0.54) are investigated for possible applications in magnetic refrigeration. A maximum magnetic entropy change of 5.5 J/kg K and a corresponding temperature change of 2 K are estimated for x = 0.28. The magnetocaloric effect in antiferromagnetic and charge-ordering compounds is found to be small.
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Date Issued: 2005
PURL: http://purl.flvc.org/fau/fd/FADT12133
Subject Headings: Physics, Condensed Matter
Format: Document (PDF)

Title: Computational methods in metallic alloys within multiple scattering theory.
Creator: Rusanu, Aurelian, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Designing materials, particularly at the nano-scale, is an important scientific research area. It includes a large spectrum of basic science and technological developments. In order to provide results that are relevant to real materials, quantum mechanical simulations involving thousands to millions of atoms must be carried out. The locally self-consistent multiple scattering (LSMS) method is the method of choice for such calculations because it has a technical feature called order-N scaling....
Show moreDesigning materials, particularly at the nano-scale, is an important scientific research area. It includes a large spectrum of basic science and technological developments. In order to provide results that are relevant to real materials, quantum mechanical simulations involving thousands to millions of atoms must be carried out. The locally self-consistent multiple scattering (LSMS) method is the method of choice for such calculations because it has a technical feature called order-N scaling. We describe an implementation of the LSMS for massively parallel supercomputers using k-space and real-space methods. For magnetic materials, the constrained local moment approach and the exchange interaction method are used. We demonstrate our approach by calculating the electronic and magnetic structure of an iron nano-particle embedded in an iron aluminide crystal matrix.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12176
Subject Headings: Physics, Condensed Matter
Format: Document (PDF)

Title: Correlations between maxillary sinus and nasal cavity volume: An exploratory study into environmental influences on the human maxillary sinus.
Creator: Butaric, Lauren N., Florida Atlantic University, Broadfield, Douglas C., Dorothy F. Schmidt College of Arts and Letters, Department of Anthropology
Abstract/Description: Previous hypotheses have suggested that maxillary sinus volume (MSV) is dependent on nasal cavity volume (NCV), and while NCV is highly correlated with climate, MSV is a passive by-product. To test these hypotheses 39 dried adult human crania from different climatic regions were examined using CT technology. MSV and NCV were regressed against each other and cranial size-variables using least squares and reduced major axis analysis. Analysis of variance (ANOVA) tests were also utilized to...
Show morePrevious hypotheses have suggested that maxillary sinus volume (MSV) is dependent on nasal cavity volume (NCV), and while NCV is highly correlated with climate, MSV is a passive by-product. To test these hypotheses 39 dried adult human crania from different climatic regions were examined using CT technology. MSV and NCV were regressed against each other and cranial size-variables using least squares and reduced major axis analysis. Analysis of variance (ANOVA) tests were also utilized to identify significant differences in MSV and NCV between populations. Results suggest that MSV and NCV are not significantly correlated, and while NCV scales with isometry relative to skull size, scaling properties of MSV were not significant. ANOVA results show that although there are significant differences in MSV between populations, they are not due to climatic influences.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/13373
Subject Headings: Biology, Anatomy, Anthropology, Physical
Format: Document (PDF)

Title: The tight-binding coherent potential approximation embedded cluster method Monte Carlo approach and approximations to the quadratic Korringa-Kohn-Rostoker method.
Creator: Horvath, Eva Antoinette, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The coherent potential approximation (CPA) can yield information about the long-range characteristics of an alloy. However, since it is a single-site theory, the effect of the local environment cannot be taken into account. The CPA can be extended to more than one site using the embedded cluster method, thereby including short-range order effects. The tight-binding coherent-potential approximation embedded cluster method can be used to generate the densities of states corresponding to all...
Show moreThe coherent potential approximation (CPA) can yield information about the long-range characteristics of an alloy. However, since it is a single-site theory, the effect of the local environment cannot be taken into account. The CPA can be extended to more than one site using the embedded cluster method, thereby including short-range order effects. The tight-binding coherent-potential approximation embedded cluster method can be used to generate the densities of states corresponding to all possible configurations of any cluster, but in particular a cluster consisting of an atom and its nearest neighbors. It is then demonstrated that the interaction energies can be calculated and used in conjunction with the Monte Carlo approach to generate the phase diagram of an alloy. In addition, the formalism for two new approximations to the Quadratic Korringa-Kohn-Rostoker method is developed and is applied to a system consisting of one metal.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/12321
Subject Headings: Physics, Condensed Matter
Format: Document (PDF)

Title: Electronic structure calculations for alloys using the polymorphous coherent potential approximation.
Creator: Pella, Silvia, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: The Polymorphous Coherent Approximation (PCPA) plays the central role in this study. The PCPA represents an extension of the Coherent Potential Approximation (CPA) in the sense that it treats an alloy model in which all of the atoms are allowed to have distinct charges and potentials. It makes use of the supercells that contain hundreds of atoms. The Madelung potentials at all sites are calculated exactly. The present calculations demonstrate the advantages of the PCPA over the CPA in...
Show moreThe Polymorphous Coherent Approximation (PCPA) plays the central role in this study. The PCPA represents an extension of the Coherent Potential Approximation (CPA) in the sense that it treats an alloy model in which all of the atoms are allowed to have distinct charges and potentials. It makes use of the supercells that contain hundreds of atoms. The Madelung potentials at all sites are calculated exactly. The present calculations demonstrate the advantages of the PCPA over the CPA in explaining experiments that depend critically on the charge transfer in an alloy.
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Date Issued: 2003
PURL: http://purl.flvc.org/fau/fd/FADT12029
Subject Headings: Physics, Condensed Matter
Format: Document (PDF)

Title: Epitaxial bain paths and metastable phases of tetragonal iron and manganese.
Creator: Ma, Hong, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Physics
Abstract/Description: Epitaxial Bain paths and metastable states of tetragonal Fe and Mn have been studied by first-principles total-energy calculations using the full-potential linearized-augmented-plane-wave method. The main accomplishments are as follows. (1) We have performed the first ever EBP calculation of tetragonal antiferromagnetic (AF) Mn showing that when grown epitaxially on Pd(001), the AF Mn film is strained gamma-Mn, but grown on V(001) the film is strained delta-Mn, which could not be determined...
Show moreEpitaxial Bain paths and metastable states of tetragonal Fe and Mn have been studied by first-principles total-energy calculations using the full-potential linearized-augmented-plane-wave method. The main accomplishments are as follows. (1) We have performed the first ever EBP calculation of tetragonal antiferromagnetic (AF) Mn showing that when grown epitaxially on Pd(001), the AF Mn film is strained gamma-Mn, but grown on V(001) the film is strained delta-Mn, which could not be determined using the available crystallographic and elastic data because they were obtained from unstrained states. (2) We have calculated the EBP's of Fe at zero pressure in four magnetic phases, i.e., ferromagnetic (FM), nonmagnetic (NM), type-I antiferromagnetic (AF1), and type-II antiferromagnetic (AF2), which show that the AF2 is the phase of the bulk of epitaxial Fe films on Cu(001) and it is unstable for [110] and [010] shears in the (001) plane, but it can be stabilized by epitaxy on Cu(001). (3)We have unified and simplified the theory of elasticity under hydrostatic pressure p at zero temperature using the Gibbs free energy G, rather than the energy E. The minima of G, but not E, with respect to strains at the equilibrium structure give the zero temperature elastic constants; the stability of a phase at p is then determined by the same Born stability conditions used at p = 0 when applied to the elastic constants from G. The EBP's of FM Fe under hydrostatic pressure show that the bcc phase exists up to 1500 kbar. A bct phase is shown to come into existence at 1300 kbar and becomes stable at 1825 kbar and above. (4) Based on this dissertation research five papers have been published in refereed journals.
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Date Issued: 2002
PURL: http://purl.flvc.org/fau/fd/FADT12021
Subject Headings: Physics, Condensed Matter
Format: Document (PDF)

Title: Structural determination of nanomolar quantities of neuroactive peptides by nuclear magnetic resonance.
Creator: Matei, Elena, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
Abstract/Description: The specificity of the conotoxin is one of the attributes that make them a valuable diagnostic tool in the characterization of neuronal mechanisms, or therapeutic agents in medicine. It appears that Nature has provided us with a pharmaceutical tool in the form of Conus peptides. Further studies will only enhance our understanding, and use, of these molecules in medicine and science. The study of three-dimensional structure in relation to the function of cone snail peptides is an area of...
Show moreThe specificity of the conotoxin is one of the attributes that make them a valuable diagnostic tool in the characterization of neuronal mechanisms, or therapeutic agents in medicine. It appears that Nature has provided us with a pharmaceutical tool in the form of Conus peptides. Further studies will only enhance our understanding, and use, of these molecules in medicine and science. The study of three-dimensional structure in relation to the function of cone snail peptides is an area of increasing interest. The venom of a single cone snail can contain as many as 300 different chemical components. Individual cone snail venom components, or conopeptides, can have powerful neurological effects. For many interesting species, not enough venom collected from the natural origin is available for experimental investigations. After a laborious separation procedure, only nanomole quantities of these native conopeptides are able to be obtained. Therefore, several experimental applications, such as NMR spectroscopy, are difficult to carry out using traditional methods. The research was focused on using nanoNMR spectroscopy as an alternative method to the conventional NMR spectroscopy method in order to analyze small quantities of novel peptides with unknown three-dimensional conformational arrangement. The experimental results obtained using the HR-MAS NMR technique, in addition to the use of a 3mm gHCN (with 1.7mm inserts) NMR probes, proved the capability of conformational analysis of different types of natural products at sample levels down to nanomole range. Understanding the interaction between agonist or antagonist ligands and their target receptors, at a molecular level, offer promise for the development of pharmacological therapeutics for the central nervous system. Conopeptides are of great interest as ligands in neuroscience and are valuable leads in drug design, based on their specificity and potency for therapeutically relevant receptors and ion channels. For instance, the compound called Prialt (formerly known as Ziconotide), a synthetic form of a cone snail-derived peptide, is the most powerful painkiller known and has already received the Food and Drug Administration (FDA) approval. The drug is part of a new class known as the N-type calcium channel blockers, which are responsible for transmitting pain signals. Several related cone snail drugs are currently in clinical trials and could eventually be used to treat different diseases such as Alzheimer's, epilepsy and Parkinson's.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/12162
Subject Headings: Physics, General, Biophysics, General
Format: Document (PDF)

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