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2018

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Articles 1741 - 1755 of 1755

Full-Text Articles in Physics

Comparative Study Of Cv3 Carbonaceous Chondrites Allende And Bali Using Micro-Raman Spectroscopy And Sem/Eds, Raka Paul Jan 2018

Comparative Study Of Cv3 Carbonaceous Chondrites Allende And Bali Using Micro-Raman Spectroscopy And Sem/Eds, Raka Paul

All Graduate Theses, Dissertations, and Other Capstone Projects

The birth of the solar system (over 4 billion years) is speculated to have happened from a nebula, swirling and compacting in localized regions to eventually form the Sun and planets. This complex process consists of numerous changes and intermediary steps, yet to be fully understood. Carbonaceous chondritic meteorites are relics of that process and therefore have potential to reveal information about the formation history. Several theories have been formulated linking their composition to planet formation. This study focusses on two carbonaceous chondritic specimens, Allende and Bali, both of the group CV and petrologic type 3. CV meteorites are abundant …

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Nonlinear Coupled Effects In Nanomaterials, Sia Bhowmick Jan 2018

Nonlinear Coupled Effects In Nanomaterials, Sia Bhowmick

Theses and Dissertations (Comprehensive)

Materials at the nanoscale have different chemical, structural, and optoelectrical properties compared to their bulk counterparts. As a result, such materials, called nanomaterials, exhibit observable differences in certain physical phenomena. One such resulting phenomenon called the piezoelectric effect has played a crucial role in miniature self-powering electronic devices called nanogenerators which are fabricated by using nanostructures, such as nanowires, nanorods, and nanofilms. These devices are capable of harvesting electrical energy by inducing mechanical strain on the individual nanostructures. Electrical energy created in this manner does not have environmental limitations. In this thesis, important coupled effects, such as the nonlinear piezoelectric …

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Enabling Quantification Of Protein Concentration In Human Serum Biopsies Using Attenuated Total Reflectance – Fourier Transform Infrared (Atr-Ftir) Spectroscopy, Kate Spalding, Franck Bonnier, Clément Bruno, Hélène Blasco, Ruth E. Board, Isabelle Benz-De-Bretagne, Hugh Byrne, Holly J. Butler, Igor Chourpa, Pretheepan Radhakrishnan, Matthew J. Baker Jan 2018

Enabling Quantification Of Protein Concentration In Human Serum Biopsies Using Attenuated Total Reflectance – Fourier Transform Infrared (Atr-Ftir) Spectroscopy, Kate Spalding, Franck Bonnier, Clément Bruno, Hélène Blasco, Ruth E. Board, Isabelle Benz-De-Bretagne, Hugh Byrne, Holly J. Butler, Igor Chourpa, Pretheepan Radhakrishnan, Matthew J. Baker

Articles

Changes in protein concentrations within human blood are used as an indicator for nutritional state, hydration and underlying illnesses. They are often measured at regular clinical appointments and the current analytical process can result in long waiting times for results and the need for return patient visits. Attenuated total reflectance – Fourier transform infrared (ATR-FTIR) spectroscopy has the ability to detect minor molecular differences, qualitatively and quantitatively, in biofluid samples, without extensive sample preparation. ATR-FTIR can return an analytical measurement almost instantaneously and therefore could be deemed as an ideal technique for monitoring molecular alterations in blood within the clinic. …

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Application Of Box-Behnken Experimental Design For The Formulation And Optimisation Of Selenomethionine-Loaded Chitosan Nanoparticles Coated With Zein For Oral Delivery., Giuliana Vozza, Hugh Byrne, Jesus Maria Frias, Minna Khalid Danish, Sinéad M. Ryan Jan 2018

Application Of Box-Behnken Experimental Design For The Formulation And Optimisation Of Selenomethionine-Loaded Chitosan Nanoparticles Coated With Zein For Oral Delivery., Giuliana Vozza, Hugh Byrne, Jesus Maria Frias, Minna Khalid Danish, Sinéad M. Ryan

Articles

Selenomethionine is an essential amino acid with a narrow therapeutic index and susceptibility to oxidation. Here it was encapsulated into a nanoparticle composed of chitosan cross-linked with tripolyphosphate for oral delivery. The formulation was optimised using a three-factor Box-Behnken experimental design. The chitosan:tripolyphosphate ratio, chitosan solvent pH, and drug load concentration were independently varied. The dependent variables studied were encapsulation efficiency, particle size, polydispersity index and zeta potential. For optimisation, encapsulation efficiency and zeta potential were maximised, particle diameter was set to 300 nm and polydispersity index was minimised. A 0.15 mg/mL concentration of selenomethionine, chitosan solvent pH of 3, …

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Van Der Waals Interactions In Ultrafine Nanocellulose Aerogels, Byron John Fritch Jan 2018

Van Der Waals Interactions In Ultrafine Nanocellulose Aerogels, Byron John Fritch

Honors Program Theses

The purpose of this study was to establish methods of synthesizing various compositions of nanocellulose aerogels using a top-down ultrasonication synthesis approach. Quantifying the effect composition has on physical properties was also be of interest due to the lack of scientific literature over this material. Microscopic techniques and physical experiments were used to determine how the internal structure of the aerogel material varies with composition and how the internal structure effects the physical properties. The main driving factor behind this study was that not much current scientific literature can be found about how the ultrasonic process effects the nanocellulose aerogels. …

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Two-Electrode Measurements Of Electrostatic Double Layer Potentials With Atomic Force Microscopy, Jason Giamberardino Jan 2018

Two-Electrode Measurements Of Electrostatic Double Layer Potentials With Atomic Force Microscopy, Jason Giamberardino

Theses and Dissertations

In this dissertation, I provide a thorough description of my development of theoretical, analytical, and experimental techniques pertaining to novel measurements of the electrostatic double layer (EDL) using atomic force microscopy (AFM), among other techniques. The EDL refers to the structure formed by ions that exists at the interface between a solid and a liquid. The EDL is an important physical element of many systems and its behavior has been of interest to scientists for many decades. Because many areas of science and engineering are moving to test, build, and understand systems at smaller and smaller scales, this work focuses …

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Ecology And Virulence Capabilities Of Vibrios Isolated From The Pristine North Inlet Estuary, Savannah Leigh Klein Jan 2018

Ecology And Virulence Capabilities Of Vibrios Isolated From The Pristine North Inlet Estuary, Savannah Leigh Klein

Theses and Dissertations

Vibrio bacteria are Gram negative, motile organisms that occur naturally in most coastal and estuarine ecosystems. Some vibrios are important human pathogens, including Vibrio parahaemolyticus and Vibrio vulnificus. The CDC estimates that vibrios cause 80,000 cases of disease each year in the United States alone. Most cases are caused by V. parahaemolyticus, which infects humans after the consumption of contaminated raw or undercooked seafood, primarily oysters. V. parahaemolyticus causes mild gastroenteritis that is self-limiting unless the patient is immunocompromised. V. vulnificus has a much lower incidence of disease (100 cases in the USA yr-1); however, this organism causes much more …

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Optical Investigation Of A Hybrid System Of Plasmonic Structures And Semiconductor Quantum Dots, Matthew B. Seaton Jan 2018

Optical Investigation Of A Hybrid System Of Plasmonic Structures And Semiconductor Quantum Dots, Matthew B. Seaton

Theses and Dissertations

Next generation integrated nanophotonic devices must fabricate large numbers of nanoscaled light coupling structures onto a single wafer: emitters such as quantum dots, resonators such as nanocavities and plasmonic nanoparticles, photonic crystal and nano-plasmonic waveguides, among others. Before precision planning and engi- neering will be possible a thorough understanding of the interaction between these structures must be documented. We present in this work an investigation of the interaction between quantum dots and plasmonic structures in the weak coupling regime. We found that surface plasmon supporting silver structures placed about 100nm from InGaAs quantum dots enabled an all optical polarization dependent …

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Depairing Current Density In Nbtin Superconducting Films, Nahid Shayesteh Swails Jan 2018

Depairing Current Density In Nbtin Superconducting Films, Nahid Shayesteh Swails

Theses and Dissertations

In this work, we systematically investigate the superconducting properties of Niobium Titanium Nitride (NbTiN) superconducting films with different geometries, which at low temperature remain superconducting. NbT iN superconducting films with a few nm thickness are widely used in devices such as superconductor-insulatorsuperconductor (SIS) mixers, superconducting cavities and resonators and superconducting nanowire single-photon detectors (SNSPD). In all these applications, films of varying dimensions are required to achieve optimal performance. The initial thickness of our samples was 125 nm deposited on a silicon substrate. We change the thickness of our samples using lithography and ion milling. We measure and analyze the thickness …

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Branching Fractions And Amplitude Analysis Of B± → Φks0Π± Decays, Alyssa D. Loos Jan 2018

Branching Fractions And Amplitude Analysis Of B± → Φks0Π± Decays, Alyssa D. Loos

Theses and Dissertations

The Belle detector is a particle physics detector that is located around the collision point of the asymmetric-energy e+e- collider KEKB. Both detector and collider are located at the KEK international lab in Japan. This thesis uses the full Belle data sample of 772 × 106 BB¯ pairs collected at the Υ(4S) resonance. Decays with large b → s penguin transitions in the standard model (SM), such as B± → φKS0π±, could be a source of CP violation. This is important in the race to find the mechanism behind the universe’s matter-antimatter imbalance. b → s penguin transitions allow us …

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An Axion Search With The Majorana Demonstrator, Clinton Gray Wiseman Jan 2018

An Axion Search With The Majorana Demonstrator, Clinton Gray Wiseman

Theses and Dissertations

The Majorana Demonstrator is an array of P-type point contact (PPC) germanium detectors enclosed in a multi-layered shield at the 4850’ level of the Sanford Underground Research Facility. Its primary goal is to search for the neutrinoless double beta decay of 76Ge. The initial 10 kg-y dataset, taken over a two year period, has energy thresholds as low as 1 keV. This allows concurrent rare event searches for the signatures of dark matter and solar axions in the low energy spectrum. Though the detectors are routinely operated with sub-keV energy thresholds, changing noise conditions in the array have made it …

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High Accuracy Methods And Regularization Techniques For Fluid Flows And Fluid-Fluid Interaction, Mustafa Aggul Jan 2018

High Accuracy Methods And Regularization Techniques For Fluid Flows And Fluid-Fluid Interaction, Mustafa Aggul

Dissertations, Master's Theses and Master's Reports

This dissertation contains several approaches to resolve irregularity issues of CFD problems, including a decoupling of non-linearly coupled fluid-fluid interaction, due to high Reynolds number. New models present not only regularize the linear systems but also produce high accurate solutions both in space and time. To achieve this goal, methods solve a computationally attractive artificial viscosity approximation of the target problem, and then utilize a correction approach to make it high order accurate. This way, they all allow the usage of legacy code | a frequent requirement in the simulation of fluid flows in complex geometries. In addition, they all …

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Probing Quantum Transport In Three-Terminal Nanojunctions, Meghnath Jaishi Jan 2018

Probing Quantum Transport In Three-Terminal Nanojunctions, Meghnath Jaishi

Dissertations, Master's Theses and Master's Reports

One-dimensional (1D) nanoscale systems—structures with the lateral dimensions ranging from 1 nm to 100 nm — have received significant research interest due to their unique structure-guided properties that promise functionalities far more superior than their bulk counterparts. The quantum confinement effect in 1D nanostructures provides us with a very powerful tool to tune their electrical, magnetic, optical and thermal properties and opens the gateway for their multifunctional usages in next-generation electronics. In particular, carbon nanotubes and semiconductor nanowires are found to offer tremendous opportunities to form the junction devices with controlled electronic and optoelectronic properties crucial to predictable device functions. …

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Generalizable Modeling Of Charge Transport In Single Electron Transistor Devices: Application To Thermal Sensitivity In Semiconducting Island Systems, Paniz Khanmohammadi Hazaveh Jan 2018

Generalizable Modeling Of Charge Transport In Single Electron Transistor Devices: Application To Thermal Sensitivity In Semiconducting Island Systems, Paniz Khanmohammadi Hazaveh

Dissertations, Master's Theses and Master's Reports

Electronic devices, especially MOSFETs, have been dimensionally scaled down to enhance operation of integrated circuits, addressing challenges such as current leakage, fluctuation of intrinsic semiconductor properties, and power dissipation. Reaching dimensions below 20 nm, there are fundamental limitations that are difficult to overcome, driving alternative device paradigms to be sought utilizing the quantum mechanical behavior of electrons. Single electron transistor (SET) devices are examples of a new generation of low-power transistors designed to transport information via single electron tunneling through one or more islands separated by tunnel junctions. Experimentally explored SET devices have shown that there are advantages to using …

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Magnetless And Topological Edge Mode-Based On-Chip Isolators And Spin-Orbit Coupling In Magneto-Optic Media, Dolendra Karki Jan 2018

Magnetless And Topological Edge Mode-Based On-Chip Isolators And Spin-Orbit Coupling In Magneto-Optic Media, Dolendra Karki

Dissertations, Master's Theses and Master's Reports

The rapid growth of optical communication networks requires monolithic integration of various optical components such as lasers, modulators, detectors, amplifiers. Optical feedback due to reflected light at the interfaces of several components in a photonic circuit has detrimental effects to the normal operation of laser by increasing noise, forcing laser to oscillate into different lasing modes etc. So optical isolators are crucial components to make complex optical circuits possible by preventing the feedback signal from coupling back to the lasers sources. For this purpose, an optical isolator that can reduce the feedback signal by > 30 dB and at the same …

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