Physics Commons^™

Photo-Production Of Eta Mesons, Mahmoud Mohamed Kamel

FIU Electronic Theses and Dissertations

In this work we present the GlueX experiment extensive high statistics measurements of the η meson photo-production differential cross sections at beam energies between 3 GeV and 11.6 GeV. We compared the low energy (2.9 GeV< Eγ < 5.9 GeV) differential cross section (dσ/dΩ) results to previous experimental results from the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) collaboration. These (dσ/dΩ) results are also compared to the theoretical isobar model EtaMAID2018 by Tiator et. al., and the Regge model by Nys et. al. The differential cross section dσ/dt is also presented and compared to the previous experimental results, and to the above models, in addition to a model by J. M. Laget. The high energy (6.2 GeV< Eγ < 11.6 GeV) cross section results (dσ/dΩ, and dσ/dt) are compared to the isobar model EtaMAID2018. These results will provide new constraints on η photo-production mechanisms and high energy t- channel processes.

Organic-Inorganic Halide Perovskite Nanocrystals And Solar Cells, Rui Guo

FIU Electronic Theses and Dissertations

A great challenge facing humanity in the 21^st century is finding inexhaustible and inexpensive energy sources to power the planet. Renewable energies are the best solutions because of their abundance, diversity, and pollution-free emission. Solar energy is the cleanest and most abundant renewable energy source available. In the continuing quest for efficient and low-cost solar cells, perovskite solar cells (PSCs) have emerged as a potential replacement for silicon solar cells. Since 2009, the record efficiencies of PSCs have been skyrocketing from 3.8 % to 25.2 % and are now approaching the theoretical limit. Along with the three-dimensional perovskites used …

Surface-Enhanced Raman Spectroscopy For Single Molecule Analysis And Biological Application, Jing Guo

FIU Electronic Theses and Dissertations

Surface-enhanced Raman spectroscopy (SERS) is a surface analytical technique, which enhances the Raman signal based on the localized surface plasmon resonance (LSPR) phenomenon. It has been successfully used for single molecule (SM) detection and has extended SERS to numerous applications in biomolecular detection. However, SM detection by SERS is still challenging especially with traditional SERS substrates and detection methods. In addition, the fundamental understanding of the SERS enhancement mechanism is still elusive. Furthermore, the application of SERS in biological field is still in the early stage. To address these challenges, there are two main aspects of SERS studied in my …

Investigations Of Cell-Penetrating And Membrane-Pore Forming Peptides, Rudramani Pokhrel

FIU Electronic Theses and Dissertations

Cell-penetrating and membrane-pore forming peptides are a class of membrane-active peptides. They are short sequence peptides having both hydrophilic and lipophilic combinations of amino acids. These peptides can have contrast functional diversity. Peptides encoded by viruses function as viroporins and play a critical role in viral replication, propagation, and pathogenesis. One such peptide is the Ebola virus delta peptide, which forms a pore in the host cell membrane. Another set of pore-forming peptides are antimicrobial Lantibiotic peptides that may be useful for killing antibiotic resistant bacteria by disrupting the bacterial membrane through two different possible mechanisms. Not only can they …

Cross Section Measurements Of Deuteron Electro-Disintegration At Very High Recoil Momenta And Large 4-Momentum Transfers (Q2), Carlos Yero

FIU Electronic Theses and Dissertations

The ²H(e,e′p)n cross sections have been measured at negative 4-momentum transfers of Q² = 4.5±0.5 (GeV/c)² and Q² = 3.5±0.5 (GeV/c)² reaching neutron recoil (missing) momenta up to p_r ∼1.0 GeV/c. The data have been obtained at fixed neutron recoil angles 5^o ≤ θ_nq ≤ 95^o with respect to the 3-momentum transfer q. The new data agree well with the previous data which reached p_r ∼ 500 MeV/c. At θ_nq = 35^o and 45^o, final state interactions (FSI), meson exchange currents (MEC) and isobar configurations (IC) …

Multifunctional Nanopipette For Single Nanoparticles And Proteins Analysis, Popular Pandey

FIU Electronic Theses and Dissertations

Complex biological processes occur in the nanoscale (1-100 nm) regime. ‘DNA’ which is just 2 nm in dimension is a fundamental building block of all life. ‘Hemoglobin’, a blood protein that transports oxygen throughout our body is only 5 nm in diameter. Importantly, the structure, composition, and dynamics of these nanoscale entities determine their biological function. A slight alteration in the structure and composition can lead to the malfunction of the protein which is key to various diseases including cancer. Therefore, the single-molecule measurement approach is essential to characterize both the average properties and the rare …

The Impacts Of Small Group Interactions And Social Interdependence In Introductory Physics, Miguel Angel Rodriguez Velazquez

FIU Electronic Theses and Dissertations

The collected works in my dissertation are centered around the dynamics and impacts of small group learning in introductory physics. It is motivated by a desire to better understand which classroom practices and learning processes may lead to students achieving greater understanding or affinity to physics. Several theoretical frameworks are leveraged in my work including physics identity theory, social interdependence theory and social metacognition. The research design employed quantitative and qualitative methods including regression analysis, descriptive statistics, and observational analysis.

Firstly, students across the U.S. enrolled in first semester introductory physics courses were surveyed at the beginning and end of …