Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Engineering (7)
- Engineering Science and Materials (5)
- Materials Science and Engineering (5)
- Mechanics of Materials (5)
- Optics (3)
-
- Electrical and Computer Engineering (2)
- Life Sciences (2)
- Atmospheric Sciences (1)
- Biochemistry, Biophysics, and Structural Biology (1)
- Bioinformatics (1)
- Biomedical (1)
- Biophysics (1)
- Chemistry (1)
- Earth Sciences (1)
- Electrical and Electronics (1)
- Elementary Particles and Fields and String Theory (1)
- Geophysics and Seismology (1)
- Nanoscience and Nanotechnology (1)
- Oceanography and Atmospheric Sciences and Meteorology (1)
- Keyword
-
- Raman (3)
- DFT (2)
- Dopamine (2)
- Graphene (2)
- Spectroscopy (2)
-
- AC Impedance Spectroscopy (1)
- AC Susceptibility (1)
- Adsorption (1)
- Aerosol Optical Depth (1)
- Asphaltene (1)
- Binding Energy (1)
- Boron-doped diamond (1)
- Breast Cancer (1)
- Composite (1)
- Conductivity (1)
- Confocal Raman mapping (1)
- Cyclic Adenosine Monophosphate (1)
- Diagnosis (1)
- Diamond thin films (1)
- Diffusion (1)
- Dilatancy model (1)
- Doped Graphene (1)
- Drosophila (1)
- Drude model (1)
- EGFR (1)
- El Paso-Juarez Airshed (1)
- Electron Paramagnetic Resonance(EPR) (1)
- Endohedral Metallofullerene (1)
- Energy Dispersive Spectroscopy (1)
- Fiber Bragg Grating (1)
Articles 1 - 17 of 17
Full-Text Articles in Physics
Methods For Producing Graphene From Petroleum By-Products, Eva M. Deemer
Methods For Producing Graphene From Petroleum By-Products, Eva M. Deemer
Open Access Theses & Dissertations
N/A
Study Of Electron Gas On A Neutron-Rich Nuclear Pasta, Enrique Ramirez-Homs
Study Of Electron Gas On A Neutron-Rich Nuclear Pasta, Enrique Ramirez-Homs
Open Access Theses & Dissertations
This study used a classical molecular dynamics model to observe the role of electron gas on the formation of nuclear structures at subsaturation densities (Ï?<0.015 fm^-3) and low temperatures (T< 1MeV ). The simulations were performed by varying the Coulomb interaction strength on systems of isospin symmetric and asymmetric matter with periodic boundary conditions. The effect was quantified on the fragment size multiplicity, the inter-particle distance, the isospin content of the clusters, the nucleon mobility and cluster persistence, and on the nuclear structure shapes. The existence of the nuclear pasta structures was observed even with the absence of the Coulomb interaction but with a modication of the shapes formed. It was found that the presence of the electron gas tends to distribute matter more evenly, forms less compact objects, decreases the isospin content of clusters, modies the nucleon mobility, reduces the persistence and the fragment size multiplicity, but does not alter the inter-particle distance in clusters. The degree of these effects also varied on the nuclear structures and depended on their isospin content, temperature, and density.
Raman Microscopic Analysis Of Internal Stress In Boron-Doped Diamond Thin Films, Emma M.A. Sundin
Raman Microscopic Analysis Of Internal Stress In Boron-Doped Diamond Thin Films, Emma M.A. Sundin
Open Access Theses & Dissertations
The correlations between induced stress on undoped and boron-doped diamond (BDD) thin films, sample chemical composition, and fabrication substrate are investigated in this study via confocal Raman microspectroscopic analysis. Stability of BDD films is relevant to fast-scan cyclic voltammetry, as film delamination and dislocation of BDD-coated electrodes that can occur during neurosurgical electrode implantation can negatively impact the biosensing reliability of this technique. Electrodes were fabricated by coating cylindrical tungsten rods using a custom-built chemical vapor deposition reactor. The results of the analysis reveal a direct correlation between regions of pure diamond and enhanced material stress, as well as preferential …
Spectroscopic Analysis Of Neurotransmitters: A Theoretical And Experimental Raman Study, Matthew Alonzo
Spectroscopic Analysis Of Neurotransmitters: A Theoretical And Experimental Raman Study, Matthew Alonzo
Open Access Theses & Dissertations
Surface-enhanced Raman spectroscopy (SERS) was applied to investigate the feasibility in the detection and monitoring of the dopamine (DA) neurotransmitter adsorbed onto silver nanoparticles (Ag NPs) at 10-11 molar, a concentration far below physiological levels. In addition, density functional theory (DFT) calculations were obtained with the Gaussian-09 analytical suite software to generate the theoretical molecular configuration of DA in its neutral, cationic, anionic, and dopaminequinone states for the conversion of computer-simulated Raman spectra. Comparison of theoretical and experimental results show good agreement and imply the presence of dopamine in all of its molecular forms in the experimental setting. The dominant …
Label-Free Raman Imaging To Monitor Breast Tumor Signatures, John Ciubuc
Label-Free Raman Imaging To Monitor Breast Tumor Signatures, John Ciubuc
Open Access Theses & Dissertations
Methods built on Raman spectroscopy have shown major potential in describing and discriminating between malignant and benign specimens. Accurate, real-time medical diagnosis benefits in substantial improvements through this vibrational optical method. Not only is acquisition of data possible in milliseconds and analysis in minutes, Raman allows concurrent detection and monitoring of all biological components. Besides validating a significant Raman signature distinction between non-tumorigenic (MCF-10A) and tumorigenic (MCF-7) breast epithelial cells, this study reveals a label-free method to assess overexpression of epidermal growth factor receptors (EGFR) in tumor cells. EGFR overexpression sires Raman features associated with phosphorylated threonine and serine, and …
Ac Susceptibility And Epr Investigations Of Superspin Dynamics In Manganese Oxide Nanoparticles, Mahesh Koirala
Ac Susceptibility And Epr Investigations Of Superspin Dynamics In Manganese Oxide Nanoparticles, Mahesh Koirala
Open Access Theses & Dissertations
We have investigated the superspin dynamics of 5 nm and 10 nm mixed state Mn3O4 nanoparticles utilizing ac-susceptibility and electron paramagnetic resonance measurements. The out of phase component of the ac-susceptibility measurements show a magnetic anomaly below (T
Neutrino Oscillations And The Reno Experiment, Karla Rosita Tellez Giron Flores
Neutrino Oscillations And The Reno Experiment, Karla Rosita Tellez Giron Flores
Open Access Theses & Dissertations
Neutrinos are the second most common particles in the universe, after the photons. Neutrinos (and antineutrinos) exist in three different "flavors", namely, electron, tau and muon neutrinos. A physical neutrino, however, can oscillate among these three flavors and, thus, it is said to be a mix of the three flavor states. In quantum mechanics representation, it is said that the three flavor states are the mixture of the three mass states. This mixture of neutrinos can generally be parameterized by the three so-called mixing angles (&thetas;12, &thetas;23, &thetas;13), three squared mass differences Δmij 2, i, j = 1, 2, 3 …
Dft Study Of Adsorption Of Trimetallic Endohedral Fullerenes On Graphene, Nakul Nitin Karle
Dft Study Of Adsorption Of Trimetallic Endohedral Fullerenes On Graphene, Nakul Nitin Karle
Open Access Theses & Dissertations
A density functional theory (DFT) study on the geometric and electronic structure of C60 and Sc3N@C80 along with their adsorption on pristine single layer graphene (SLG) is presented. C60 is found to adsorb in two nearly degenerate configurations: (i) with a pentagon facing the SLG, which is the most stable one, and (ii) with a hexagon facing the SLG in a face-to-face perfect alignment, rarely common in Ï?â??Ï? interactions, 0.06 eV higher in energy. The calculated binding energy of 0.76 eV, which includes dispersion effects, is in good agreement with previous theoretical and experimental reports. On the contrary, Sc3N@C80 adsorption …
Self-Interaction Corrected Polarizabilities Of Small Molecules, Sharmin Akter
Self-Interaction Corrected Polarizabilities Of Small Molecules, Sharmin Akter
Open Access Theses & Dissertations
Density Functional Theory (DFT) is one of the most successful and popular computational Quantum Mechanical approaches to understand materials. DFT allows the prediction of material properties from the electron density. Although in principle density functional theory is exact, it, however, relies on approximate functional for exchange-correlation energy. Due to the approximate nature of the exchange-correlation functional, the self-Coulomb energy of the electrons is not exactly canceled out by the self-exchange leading the spurious self-interaction error (SIE). This error is responsible for the unphysical orbital energies of DFT and delocalization of the orbitals. The orbital energies of the valence electrons are …
Time Degradation Of Perovskites, Nazia Sharmin
Time Degradation Of Perovskites, Nazia Sharmin
Open Access Theses & Dissertations
Perovskite organic-inorganic compounds are of interest for photovoltaic purposes, unfortunately, some of the organic-inorganic elements tend to evaporate rather rapidly rendering the films less effective for photoelectric use. In this study, we examine the evaporation of Perovskite organic-inorganic compounds produced by several manufacturing techniques. In particular we perform XRF and XPS inspections as a function of time and determine the fabrication method that best conserves iodine and lead.
Bragg Gratings In Polarization Maintaining Optical Fiber As Three Dimensional Strain Sensor, Joel Quintana
Bragg Gratings In Polarization Maintaining Optical Fiber As Three Dimensional Strain Sensor, Joel Quintana
Open Access Theses & Dissertations
Fiber-Bragg Gratings (FBG) for Structural Health Monitoring (SHM) have been studied extensively as they offer electrically passive operation, electromagnetic interference (EMI) immunity, high sensitivity and multiplexing as compared to conventional electric strain sensors. FBG sensors written within polarization maintaining (PM) optical fiber offer ad- ditional dimensions of strain measurement, greatly reducing the number of sensors needed to properly monitor a structure. This reduction however, adds complexity to the dis- crimination of the sensorâ??s optical response to its corresponding applied strains. This Dissertation defines the set of algorithms needed to measure planar strain using PM-FBGs exclusively. It defines the minimum number …
Imaging Live Drosophila Brain With Two-Photon Fluorescence Microscopy, Syeed Ehsan Ahmed
Imaging Live Drosophila Brain With Two-Photon Fluorescence Microscopy, Syeed Ehsan Ahmed
Open Access Theses & Dissertations
Two-photon fluorescence microscopy is an imaging technique which delivers distinct benefits for in vivo cellular and molecular imaging. Cyclic adenosine monophosphate (cAMP), a second messenger molecule, is responsible for triggering many physiological changes in neural system. However, the mechanism by which this molecule regulates responses in neuron cells is not yet clearly understood. When cAMP binds to a target protein, it changes the structure of that protein. Therefore, studying this molecular structure change with fluorescence resonance energy transfer (FRET) imaging can shed light on the cAMP functioning mechanism. FRET is a non-radiative dipole-dipole coupling which is sensitive to small distance …
Studies Of Direct Solar Irradiance And Aerosol Optical Depth Using An Mfrsr And A Microtop Sunphotometer In The El Paso-Juarez Airshed, Arjun Aryal
Open Access Theses & Dissertations
The study of Solar Irradiance and Aerosol Optical Depth (AOD) plays an important role in understanding the regional and global climate distribution, and is also important in air pollution studies. In this work an MFRSR (Multi-Filter Rotating Shadowband Radiometer) and a Portable Microtop Sunphotometer were used to measure irradiances and to obtain optical depth values for the El Paso-Juarez Airshed. The Langley method applied on the MFRSR irradiance data was used to calculate the AOD values. The spatial distribution of AOD for this region was obtained using a Microtop Sunphotometer. The graphs were generated using GIS Shapefiles. In addition, the …
Structural Modifications In The Rbxcs1-Xpo 4 (0 ≤ X ≤ 1) Superprotonic Conductor Series: A Single-Crystal X-Ray Diffraction And Impedance Spectroscopy Study, Andres Jose Encerrado Manriquez
Structural Modifications In The Rbxcs1-Xpo 4 (0 ≤ X ≤ 1) Superprotonic Conductor Series: A Single-Crystal X-Ray Diffraction And Impedance Spectroscopy Study, Andres Jose Encerrado Manriquez
Open Access Theses & Dissertations
We have used single-crystal X-ray diffraction measurements to investigate the structural modifications induced by Rb-doping of the protonic conductor CsH2PO4. Data collected on the RbxCs 1-xH2PO4 (0 ≤ x ≤ 1) series shows that the monoclinic P21/m CsH2PO4 presentation persists upon Rb-doping up until x = 0.8. Rb0.8Cs0.2H2PO 4 exhibits a previously unreported P21/c monoclinic structure, where the mirror plane is lost and disorder is present in the PO4 tetrahedra even at room temperature. Higher levels of x display a tetragonal I-42d unit cell isomorphic with the known structure of RbH2PO 4. The temperature dependence of the proton conductivity determined …
Using Underground Radon To Detect Inactive Geological Faults, Germán Rodríguez Ortiz
Using Underground Radon To Detect Inactive Geological Faults, Germán Rodríguez Ortiz
Open Access Theses & Dissertations
This Thesis presents the results of an investigation of the concentration of radon in soil around a fault in the East Franklin Mountains in the El Paso area in West Texas. The connection between underground radon exhalations near active faults has been known for decades, but possible similar increases of underground radon levels around inactive faults have not been studied as thoroughly. Arguing that the dilatancy-diffusion model used to explain the phenomenon near active faults does not apply to the case of inactive faults, a hypoThesis is formulated under which increased levels of underground radon must be present near inactive …
Spectroscopic And Microscopic Analysis Of Graphene For Sensor Applications, Tamanna Tasneem Khan
Spectroscopic And Microscopic Analysis Of Graphene For Sensor Applications, Tamanna Tasneem Khan
Open Access Theses & Dissertations
As a two-dimensional material, graphene shows very good thermal and electrical conductivities, which, with its unique optical properties, makes it suitable for a variety of applications. In this study, we present detailed investigations by confocal Raman and Drude model analysis of the material's changes and improvements, as it transitioned from 3D graphite to 2D graphene. Besides Raman spectral recording, which can detect single, a few, and multi-layers of graphene, confocal Raman mapping allows distinction of such domains and direct visualization of material inhomogeneity. Moreover, far-infrared transmittance measurements, which are related to electrical conductivity, demonstrate a distinct increase of conductivity with …
Electronic Structure Studies On Transition Metal Containing Endohedral Fullerenes, Carbon Onions And Zinc Sulfide Cages, Shusil Bhusal
Electronic Structure Studies On Transition Metal Containing Endohedral Fullerenes, Carbon Onions And Zinc Sulfide Cages, Shusil Bhusal
Open Access Theses & Dissertations
We present the most stable structures for VXSc3-XN@C2n (where X=1-3 and 2n=70, 76, 78 and 80) using a systematic procedure that involves all possible isomers of the host fullerene cages. Subsequently, a detailed investigation of structural and electronic properties of the lowest energy isomers is performed using density functional theory in combination with large polarized Gaussian basis sets. The search procedure developed involved structural optimizations of thousands of fullerenes and correctly identifies the experimentally observed VSc2N@C80 and V2ScN@C80 isomer as the most stable structures. The structural analysis shows that a few V-doped endohedral fullerenes do not follow the isolated pentagon …