Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Aircraft stability and control (1)
- Astronomy (1)
- Bose-Einstein Condensate (1)
- Carbon Nanopetals (1)
- Cold plasmas (1)
-
- Critical velocity (1)
- Dielectric barrier discharge (1)
- Direct Simulation Monte Carlo (DSMC) (1)
- Dissipative Particle Dynamics (1)
- Elastic (1)
- Food sterilization (1)
- Fracture (1)
- Fuzz (1)
- Heat Generation (1)
- High Energy Physics (1)
- High voltage (1)
- Inclusions (1)
- Knudsen force (1)
- Knudsen thermal force (1)
- Low Energy Helium Ion Irradiation (1)
- Low Temperature Physics (1)
- MIKRA (1)
- Modified Paschen Curve (1)
- Molecular dynamics (1)
- Molybdenum (1)
- Nanostructures (1)
- Nuclear Fusion (1)
- Optical emission spectroscopy (1)
- Overbanking tendency (1)
- PIC (1)
- Publication
- Publication Type
Articles 1 - 25 of 25
Full-Text Articles in Physical Sciences and Mathematics
The Impact Of Crystal Morphology On The Thermal Responses Of Ultrasonically-Excited Energetic Materials, J. K. Miller, J. O. Mares, I. E. Gunduz, Steven F. Son, Jeff Rhoads
The Impact Of Crystal Morphology On The Thermal Responses Of Ultrasonically-Excited Energetic Materials, J. K. Miller, J. O. Mares, I. E. Gunduz, Steven F. Son, Jeff Rhoads
Purdue Energetics Research Center Articles
The ability to detect explosive materials may be significantly enhanced with local increases in vapor pressure caused by an elevation of the materials'temperature. Recently, ultrasonic excitation has been shown to generate heat within plastic-bonded energetic materials. To investigate the impact of crystal morphology on this heating, samples of elastic binder are implanted with single ammonium perchlorate crystals of two distinct shape groups. Contact piezoelectric transducers are then used to excite the samples at ultrasonicfrequencies. The thermal responses of the crystals are recorded using infrared thermography, and the rate of heating is estimated. Surface temperature increases up to 15 °C …
Effect Of Helium Ions Energy On Molybdenum Surfaces Under Extreme Conditions, Joseph Fiala, Jitendra K. Tripathi, Sean Gonderman, Ahmed Hassanein
Effect Of Helium Ions Energy On Molybdenum Surfaces Under Extreme Conditions, Joseph Fiala, Jitendra K. Tripathi, Sean Gonderman, Ahmed Hassanein
The Summer Undergraduate Research Fellowship (SURF) Symposium
Plasma facing components (PFCs) in fusion devices must be able to withstand high temperatures and erosion due to incident energetic ion radiations. Tungsten has become the material of choice for PFCs due to its high strength, thermal conductivity, and low erosion rate. However, its surface deteriorates significantly under helium ion irradiation in fusion-like conditions and forms nanoscopic fiber-like structures, or fuzz. Fuzz is brittle in nature and has relatively lower thermal conductivity than that of the bulk material. Small amounts of fuzz may lead to excessive contamination of the plasma, preventing the fusion reaction from taking place. Despite recent efforts, …
Using Dissipative Particle Dynamics For Modeling Surfactants, Yuchen Zhang, Arezoo M. Ardekani
Using Dissipative Particle Dynamics For Modeling Surfactants, Yuchen Zhang, Arezoo M. Ardekani
The Summer Undergraduate Research Fellowship (SURF) Symposium
Oil recovery is an industrial process that injects aqueous solutions into an oil reservoir to pump out crude oil and promote the oil production. The aqueous solution contains surfactants for reducing the interfacial tension (IFT) between aqueous phase and oil. The critical micelle concentration (CMC) is the concentration of surfactant above which micelles form and the interfacial tension reaches a plateau. Our research seeks to measure IFT and CMC for surfactants using dissipative particle dynamics (DPD) technique, which is a coarse-grained method based on the molecular dynamics. We first study how IFT is influenced by the surfactant concentration. Furthermore, another …
Optical Emission Spectroscopy Diagnostics Of Cold Plasmas For Food Sterilization, Abhijit Jassem, Michael Lauria, Russell Brayfield Ii, Kevin M. Keener, Allen L. Garner
Optical Emission Spectroscopy Diagnostics Of Cold Plasmas For Food Sterilization, Abhijit Jassem, Michael Lauria, Russell Brayfield Ii, Kevin M. Keener, Allen L. Garner
The Summer Undergraduate Research Fellowship (SURF) Symposium
There is a growing need for economical, effective, and safe methods of sterilizing fresh produce. The most common method is a chlorine wash, which is expensive and may introduce carcinogens. High voltage cold atmospheric pressure plasmas are a promising solution that has demonstrated a germicidal effect; however, the responsible chemical mechanisms and reaction pathways are not fully understood. To elucidate this chemistry, we used optical emission spectroscopy to measure the species produced in the plasma generated by a 60 Hz pulsed dielectric barrier discharge in a plastic box containing various fill gases (He, N2, CO2, dry …
Kinetic Modeling Of Roll To Roll Rfcvd Plasma, Kudzo S. Ahegbebu, Siva Sashank Tholeti, Alina A. Alexeenko
Kinetic Modeling Of Roll To Roll Rfcvd Plasma, Kudzo S. Ahegbebu, Siva Sashank Tholeti, Alina A. Alexeenko
The Summer Undergraduate Research Fellowship (SURF) Symposium
Roll-to-roll radio frequency plasma enhanced chemical vapor deposition (R2R RFCVD) is a technique for large-scale synthesis of high quality graphitic nanopetals. Graphitic nanopetals are petal-like graphene structures with remarkable electrical and mechanical properties with major industrial applications such as microsupercapacitors. RFCVD uses a non-equilibrium plasma with high energy electrons to catalyze chemical reactions, induce the creation of free radicals, and promote otherwise high temperature chemistry in a low temperature environment. Understanding how bulk plasma characteristics (particularly, power and number densities) vary with changing reactor parameters is an important step towards optimizing synthesis techniques. In our present work we use the …
Dsmc Simulation Of Microstructure Actuation By Knudsen Thermal Force, Aaron Pikus, Israel Sebastiao, Andrew Strongrich, Alina Alexeenko
Dsmc Simulation Of Microstructure Actuation By Knudsen Thermal Force, Aaron Pikus, Israel Sebastiao, Andrew Strongrich, Alina Alexeenko
The Summer Undergraduate Research Fellowship (SURF) Symposium
In many industrial and research applications there is a need for vacuum sensors with higher accuracy and spatial resolution than what is currently available. Examples of target applications include high-altitude platforms, satellites and in-vacuum manufacturing processes such as freeze-drying of food and pharmaceuticals. In this connection, a novel pressure sensor, named Microelectromechanical In-plane Knudsen Radiometric Actuator (MIKRA), has been developed by at Purdue University. MIKRA is based on Knudsen thermal forces generated by rarefied flow driven by thermal gradients within the microstructure Thus, the goal of this work is to model the rarefied gas flow in the MIKRA sensor under …
Experimental Design And Construction For Critical Velocity Measurement In Spin-Orbit Coupled Bose-Einstein Condensates, Ting-Wei Hsu, Yong P. Chen
Experimental Design And Construction For Critical Velocity Measurement In Spin-Orbit Coupled Bose-Einstein Condensates, Ting-Wei Hsu, Yong P. Chen
The Summer Undergraduate Research Fellowship (SURF) Symposium
Quantum simulation using ultra-cold atoms, such as Bose-Einstein Condensates (BECs), offers a very flexible and well controlled environment to simulate physics in different systems. For example, to simulate the effects of spin orbit coupling (SOC) on electrons in solid state systems, we can make a SOC BEC which mimics the behavior of SOC electrons. The goal of this project is to see how the superfluid property of BECs change in the presence of SOC. In particular, we plan to measure the critical velocity of an 87Rb BEC with and without SOC by stirring it with a laser. This laser needs …
Hyperscaling Violation And Electroweak Symmetry Breaking, Daniel Elander, Robert Lawrence, Maurizio Piai
Hyperscaling Violation And Electroweak Symmetry Breaking, Daniel Elander, Robert Lawrence, Maurizio Piai
Department of Physics and Astronomy Faculty Publications
We consider a class of simplifed models of dynamical electroweak symmetry breaking built in terms of their fve-dimensional weakly-coupled gravity duals, in the spirit of bottom-up holography. The sigma-model consists of two abelian gauge bosons and one real, non-charged scalar feld coupled to gravity in fve dimensions. The scalar potential is a simple exponential function of the scalar feld. The background metric resulting from solving the classical equations of motion exhibits hyperscaling violation, at least at asymptotically large values of the radial direction. We study the spectrum of scalar composite states of the putative dual feld theory by fuctuating the …
Partition Density Functional Theory, Jonathan R. Nafziger
Partition Density Functional Theory, Jonathan R. Nafziger
Open Access Dissertations
Partition density functional theory (PDFT) is a method for dividing a molecular electronic structure calculation into fragment calculations. The molecular density and energy corresponding to Kohn Sham density-functional theory (KS-DFT) may be exactly recovered from these fragments. Each fragment acts as an isolated system except for the influence of a global one-body 'partition' potential which deforms the fragment densities. In this work, the developments of PDFT are put into the context of other fragment-based density functional methods. We developed three numerical implementations of PDFT: One within the NWChem computational chemistry package using basis sets, and the other two developed from …
The Effect Of Macromolecular Crowding On The Structure Of The Protein Complex Superoxide Dismutase, Ajith Rathnaweera Rajapaksha Mudalige
The Effect Of Macromolecular Crowding On The Structure Of The Protein Complex Superoxide Dismutase, Ajith Rathnaweera Rajapaksha Mudalige
Open Access Dissertations
Biological environments contain between 7 - 40% macromolecules by volume. This reduces the available volume for macromolecules and elevates the osmotic pressure relative to pure water. Consequently, biological macromolecules in their native environments tend to adopt more compact and dehydrated conformations than those in vitro. This effect is referred to as macromolecular crowding and constitutes an important physical difference between native biological environments and the simple solutions in which biomolecules are usually studied.^ We used small angle scattering (SAS) to measure the effects of macromolecular crowding on the size of a protein complex, superoxide dismutase (SOD). Crowding was induced using …
Modular Approach To Spintronics, Kerem Yunus Camsari
Modular Approach To Spintronics, Kerem Yunus Camsari
Open Access Dissertations
There has been enormous progress in the last two decades, effectively combining spintronics and magnetics into a powerful force that is shaping the field of memory devices. New materials and phenomena continue to be discovered at an impressive rate, providing an ever-increasing set of building blocks that could be exploited in designing transistor-like functional devices of the future. The objective of this thesis is to provide a quantitative foundation for this building block approach, so that new discoveries can be integrated into functional device concepts, quickly analyzed and critically evaluated. Through careful benchmarking against available theory and experiments we establish …
Experimental Constraints On Exotic Spin-Dependent Interactions Using Specialized Materials, Rakshya Khatiwada
Experimental Constraints On Exotic Spin-Dependent Interactions Using Specialized Materials, Rakshya Khatiwada
Open Access Dissertations
Various theories predict the possible existence of symmetry violating forces with mesoscopic range interactions from mm-m [1]. These forces can arise from the coupling of a spin 0 boson to spin 1/2 fermions through scalar (gs) and pseudoscalar (gp) couplings. We discuss two experiments that can investigate these interactions using nucleon rich, impressively low magnetic susceptibility (5-100 times lower than pure water) test masses and electron-spin rich, polarized test masses (spin density: 10^20 h/cm3 ). The first experiment looks for a P-odd, T-odd interaction potential proportional to (S.r) where S is the spin of one particle and r is the …
Transport Studies In Graphene-Based Materials And Structures, Jiuning Hu
Transport Studies In Graphene-Based Materials And Structures, Jiuning Hu
Open Access Dissertations
Graphene, a single atomic layer of graphite, has emerged as one of the most attractive materials in recent years for its many unique and excellent properties, inviting a broad area of fundamental studies and applications. In this thesis, we present some theoretical/experimental studies about the thermal, electronic and thermoelectric transport properties in graphene-based systems. We employ the molecular dynamic simulations to study the thermal transport in graphene nanoribbons (GNRs) exhibiting various properties, including chirality dependent thermal conductivity, thermal rectification in asymmetric GNRs, defects and isotopic engineering of the thermal conductivity and negative differential thermal conductance (NDTC) at large temperature biases. …
Computational Optical Imaging: Applications In Synthetic Aperture Imaging, Phase Retrieval, And Digital Holography, Dennis Joseph Lee
Computational Optical Imaging: Applications In Synthetic Aperture Imaging, Phase Retrieval, And Digital Holography, Dennis Joseph Lee
Open Access Dissertations
Computational imaging has become an important field, as a merger of both algorithms and physical experiments. In the realm of microscopy and optical imaging, an important application is the problem of improving resolution, which is bounded by wavelength and numerical aperture according to the classic diffraction limit. We will investigate the resolution enhancement of phase objects such as transparent biological cells. One key challenge is how to measure phase experimentally. Standard interferometric techniques have the drawback of being sensitive to environmental vibrations and temperature fluctuations, and they use a reference arm which requires more space and cost. Non-holographic methods provide …
Quantitative Mrna Detection With Advanced Nonlinear Microscopy, Jing Liu
Quantitative Mrna Detection With Advanced Nonlinear Microscopy, Jing Liu
Open Access Dissertations
Cell-specific information on quantity and localization of key mRNA transcripts in single-cell level are critical to the assessment of cancer risk, therapy efficacy, and effective prevention strategies. While current techniques are not capable to visualize single mRNA transcript beyond the diffraction limit. In this thesis, two nonlinear technologies, second harmonic super-resolution microscopy (SHaSM) and transient absorption microscopy (TAM), are developed to detect and quantify single Human edimer receptor 2 (Her2) mRNA transcripts. The SHaSM is used to detect single mRNA transcript beyond the diffraction limit, while the TAM is employed to detect mRNA without the interference of fluorescence background. The …
Elastic Waves Along A Fracture Intersection, Bradley C. Abell
Elastic Waves Along A Fracture Intersection, Bradley C. Abell
Open Access Dissertations
Fractures and fracture networks play a significant role in the subsurface hydraulic connectivity within the Earth. While a significant amount of research has been performed on the seismic response of single fractures and sets of fractures, few studies have examined the effect of fracture intersections on elastic wave propagation. Intersections play a key role in the connectivity of a fracture network that ultimately affects the hydraulic integrity of a rock mass. In this dissertation two new types of coupled waves are examined that propagate along intersections. 1) A coupled wedge wave that propagates along a surface fracture with particle motion …
Circular Bessel Field Statistics And The Pursuit Of Far-Subwavelength Resolution, Yulu Chen
Circular Bessel Field Statistics And The Pursuit Of Far-Subwavelength Resolution, Yulu Chen
Open Access Dissertations
The statistical description of wave propagation in random media is important for many applications. While polarized light in systems with weakly interacting scatterers and sufficient overall scatter has zero-mean circular Gaussian statistics, the underlying assumptions break down in the Anderson localization and weakly scattering regimes. Although probability density functions for wave intensity and amplitude exist beyond Gaussian statistics, suitable statistical descriptions for the field with strong and weak random scatter were unknown. The first analytical probability density function for the field that is effective in both the Anderson localization regime and the weakly scattering regime is derived by modeling the …
An Investigation Into The Phenomenological Relation Between Solar Activity And Nuclear Beta-Decay Rates, Tasneem M. Mohsinally
An Investigation Into The Phenomenological Relation Between Solar Activity And Nuclear Beta-Decay Rates, Tasneem M. Mohsinally
Open Access Dissertations
We investigate experimental evidence for time-varying nuclear decay rates, in contrast to the widely-accepted view that nuclear decaying isotopes disintegrate at a constant rate unaffected by external conditions. We study several past cases of radioactive isotopes exhibiting annual periodicities in their decay rates, presumably related to the annual variation in Earth-Sun distance. Following recent indications of shorter-lived anomalies in 54Mn decay rates concomitant with an X-class flare in 2006, we attempt to design and develop a series of unique signal detection algorithms to identify regions of anomalous activity in a nuclear decay signal. With stringent threshold cut-offs and filtering …
The Dynamics Of Ultracold Atoms In Light-Induced Synthetic Gauge Fields, Abraham J. Olson
The Dynamics Of Ultracold Atoms In Light-Induced Synthetic Gauge Fields, Abraham J. Olson
Open Access Dissertations
A central aim of this research is to study the dynamics of ultracold atoms in synthetic gauge fields. In this work, we developed a method to optimize the evaporation of ultracold atoms to the Bose-Einstein condensate (BEC) phase. We implement a model of atomic evaporation in a trapping potential, and we find optimal parameters for the trap depth and stiffness during evaporation. Using this model, we achieve a high efficiency of optical evaporation (γ eff = 4.0).^ Using that BEC, we study the dynamics of the BEC in various light-induced synthetic gauge fields. In particular, we have studied the transition …
Experiments With Synthetic Spin-Orbit Coupling And Spin Transport In Bose Einstein Condensates, Robert John Niffenegger
Experiments With Synthetic Spin-Orbit Coupling And Spin Transport In Bose Einstein Condensates, Robert John Niffenegger
Open Access Dissertations
In this thesis I will describe my experiments to study spin transport of spin Bose Einstein Condensates (BECs) with synthetic spin-orbit coupling. First I will describe procedures used to reproduce previous experiments with synthetic gauge fields in Bose-Einstein Condensates, from constant vector potentials to synthetic electric fields and synthetic spin-orbit coupling as well as all of the necessary calibration experiments. Next I will describe new experiments measuring spin transport induced by synthetic spin-dependent electric fields in spin-orbit coupled Bose-Einstein Condensates (BECs). The one dimensional (1D) spin-orbit coupling (SOC) is created with counter propagating Raman lasers which couple hyperfine sub-levels and …
Growth Of Low Disorder Gaas/Algaas Heterostructures By Molecular Beam Epitaxy For The Study Of Correlated Electron Phases In Two Dimensions, John D. Watson
Growth Of Low Disorder Gaas/Algaas Heterostructures By Molecular Beam Epitaxy For The Study Of Correlated Electron Phases In Two Dimensions, John D. Watson
Open Access Dissertations
The unparalleled quality of GaAs/AlGaAs heterostructures grown by molecular beam epitaxy has enabled a wide range of experiments probing interaction effects in two-dimensional electron and hole gases. This dissertation presents work aimed at further understanding the key material-related issues currently limiting the quality of these 2D systems, particularly in relation to the fractional quantum Hall effect in the 2nd Landau level and spin-based implementations of quantum computation.^ The manuscript begins with a theoretical introduction to the quantum Hall effect which outlines the experimental conditions necessary to study the physics of interest and motivates the use of the semiconductor growth …
Evaluating Breast Cancer Stem Cell Response To Antiangiogenic Therapy, Connor J. Holloway
Evaluating Breast Cancer Stem Cell Response To Antiangiogenic Therapy, Connor J. Holloway
Open Access Theses
Angiogenic inhibitors function by blocking tumor cell signals used to recruit host tissue vasculature to the tumor site, thereby depriving the cancer of the nutriment needed for further expansion. The development and implementation of angiogenic inhibitors in conjunction with standard chemotherapy agents has increased progression-free survival but not overall patient survival. It is hypothesized that chronic exposure to large doses of AAT drugs worsens hypoxic conditions within the tumor mass, selectively stimulating aggressive cancer stem cell populations to grow and proliferate. ^ In this study, the expression of the CSC biomarkers ALDH1, DLL1, and EpCAM were evaluated in breast cancer …
A Contribution Toward Better Understanding Of Overbanking Tendency In Fixed-Wing Aircraft, Nihad E. Daidzic
A Contribution Toward Better Understanding Of Overbanking Tendency In Fixed-Wing Aircraft, Nihad E. Daidzic
Journal of Aviation Technology and Engineering
The phenomenon of overbanking tendency for a rigid-body, fixed-wing aircraft is investigated. Overbanking tendency is defined as a spontaneous, unbalanced rolling moment that keeps increasing an airplane’s bank angle in steep turns and must be arrested by opposite aileron action. As stated by the Federal Aviation Administration, the overbanking tendency may lead to a loss of control, especially in instrument meteorological conditions. It was found in this study that the speed differential over wing halves in horizontal turns indeed creates a rolling moment that achieves maximum values for bank angles between 45 and 55 degrees. However, this induced rolling moment …
Measurement Of The Drell--Yan Differential Cross Section With The Cms Detector At The Lhc, Alexey Svyatkovskiy
Measurement Of The Drell--Yan Differential Cross Section With The Cms Detector At The Lhc, Alexey Svyatkovskiy
Open Access Dissertations
This thesis describes precision measurements of electroweak interactions in a new energy regime and the application of these measurements to improve our understanding of the structure of the proton. The results are based on proton-proton collision data at √s = 7 and 8\TeV recorded with the Compact Muon Solenoid detector at the CERN Large Hadron Collider during the first years of operation. Measurements of the differential Drell–Yan cross section in the dimuon and dielectron channels covering the dilepton mass range of 15 to 2000\GeV and absolute dilepton rapidity from 0 to~2.4 are presented. The Drell–Yan cross section in proton-proton …
Novel Techniques For Quasi Three-Dimensional Nanofabrication Of Transformation Optics Devices, Paul R. West
Novel Techniques For Quasi Three-Dimensional Nanofabrication Of Transformation Optics Devices, Paul R. West
Open Access Dissertations
Current nanofabrication is almost exclusively limited to top-down, two-dimensional techniques. As technology moves more deeply into the nano-scale regime, fabrication of new devices with quasi three-dimensional geometries shows great potential. One excellent example of an emerging field that requires this type of non-conformal 3D fabrication technique is the field of Transformation Optics. This field involves transforming and manipulating the optical space through which light propagates. Arbitrarily manipulating the optical space requires advanced fabrication techniques, which are not possible with current two-dimensional fabrication technologies. One step toward quasi three-dimensional nanofabrication involves employing angled deposition allowing new growth mechanisms, and enabling a …