Physical Sciences and Mathematics Commons^™

Stratified Turbulence In The Nearshore Coastal Ocean: Dynamics And Evolution In The Presence Of Internal Bores, Ryan K. Walter, Michael E. Squibb, C. Brock Woodson, Jeffrey R. Koseff, Stephen G. Monismith

Physics

High-frequency measurements of stratified turbulence throughout the water column were collected over a 2 week period in the nearshore environment of southern Monterey Bay, CA, using a cabled observatory system and an underwater turbulence flux tower. The tower contained a vertical array of acoustic Doppler velocimeters and fast-response conductivity-temperature sensors, providing a nearly continuous data set of turbulent velocity and density fluctuations and a unique look into the stratified turbulence field. The evolution of various turbulence quantities and direct measurements of the vertical turbulent diffusivity is examined in the presence of nearshore internal bores, both in the near-bed region and …

High Speed Control Of Atom Transfer Sequence From Magneto-Optical To Dipole Trap For Quantum Computing, Jason Garvey Schray

Physics

Two circuits were designed, built, and tested for the purpose of aiding in the transfer of 87Rb atoms from a MOT to dipole traps and for characterizing the final dipole traps. The first circuit was a current switch designed to quickly turn the magnetic fields of the MOT off. The magnetic coil switch was able to reduce the magnetic field intensity to 5 % of its initial value after 81 μs. The second circuit was an analog signal switch designed to turn the modulation signal of an AOM off. The analog switch was able to reduce the modulation signal intensity …

Analysis And Optimization Of The Scheffler Solar Concentrator, Simone Alberti

Master's Theses

The Scheffler reflector is a new solar concentrator design which maintains a fixed focus while only having a single axis tracking mechanism. This design makes the construction and operation of high temperature solar concentrators accessible to developing nations. In this project, I wrote computer simulation codes to better understand the dynamics and the effect of deformation or deviations from ideal conditions in order to define necessary manufacturing and operational tolerances. These tools and knowledge drove the prototyping of new reflector concepts by myself and other students on my team. A fiberglass prototype was able to drive the cost of a …

Centered-Difference Applications For Schrödinger's Equation, Matthew Thomas Murachver

Physics

This project enumerates methods utilizing discretized centered-difference approximations on the second order differential equation for quantum particles known as Schrodinger’s Equation. An eigenvalue-eigenfunction scheme is developed to sieve for valid solutions to The Time Independent Schrodinger Equation. Additionally the Crank-Nicolson method is applied to the Time Dependent Schrodinger Equation to describe wavefunction (eigenfunction) time evolution. The validity of these methods is discussed with applications to several fundamental pedagogical introductory quantum mechanic systems.

Exploring The Neutrinoless Double Beta Decay In The Inverted Neutrino Hierarchy With Bolometric Detectors, D.R. Artusa, F.T. Avignone Iii, O. Azzolini, M. Balata, T.I. Banks, G. Bari, J. Beeman, F. Bellini, A. Bersani, M. Biassoni, C. Brofferio, C. Bucci, X.Z. Cai, A. Camacho, L. Canonica, X.G. Cao, S. Capelli, L. Carbone, L. Cardani, M. Carrettoni, N. Casali, D. Chiesa, N. Chott, M. Clemenza, C. Cosmelli, O. Cremonesi, R.J. Creswick, I. Dafinei, A. Dally, V. Datskov, A. De Biasi, M.M. Deninno, S. Di Domizio, M.L. Di Vacri, L. Ejzak, D.Q. Fang, H.A. Farach, M. Faverzani, G. Fernandes, E. Ferri, F. Ferroni, E. Fiorini, M.A. Franceschi, S.J. Freedman, B.K. Fujikawa, A. Giachero, L. Gironi, A. Giuliani, J. Goett, P. Gorla, C. Gotti, T.D. Gutierrez, E.E. Haller, K. Han, K.M. Heeger, R. Hennings-Yeomans, H.Z. Huang, R. Kadel, K. Kazkaz, G. Keppel, Yu. G. Kolomensky, Y.L. Li, C. Ligi, X. Liu, Y.G. Ma, C. Maiano, M. Maino, M. Martinez, R.H. Maruyama, Y. Mei, N. Moggi, S. Morganti, T. Napolitano, S. Nisi, C. Nones, E.B. Norman, A. Nucciotti, T. O'Donnell, F. Orio, D. Orlandi, J.L. Ouellet, M. Pallavicini, V. Palmieri, L. Pattavina, M. Pavan, M. Pedretti, G. Pessina, V. Pettinacci, G. Piperno, C. Pira, S. Pirro, E. Previtali, V. Rampazzo, C. Rosenfeld, C. Rusconi, E. Sala, S. Sangiorgio, N.D. Scielzo, M. Sisti, A.R. Smith, L. Taffarello, M. Tenconi, F. Terranova, W.D. Tian, C. Tomei, S. Trentalange, G. Ventura, M. Vignati, B.S. Wang, H.W. Wang, L. Wielgus, J. Wilson, L.A. Winslow, T. Wise, A. Woodcraft, L. Zanotti, C. Zarra, B.X. Zhu, S. Zucchelli

Physics

Neutrinoless double beta decay (0νββ" style="position: relative;" tabindex="0" id="MathJax-Element-1-Frame">0νββ) is one of the most sensitive probes for physics beyond the Standard Model, providing unique information on the nature of neutrinos. In this paper we review the status and outlook for bolometric 0νββ" style="position: relative;" tabindex="0" id="MathJax-Element-2-Frame">0νββ decay searches. We summarize recent advances in background suppression demonstrated using bolometers with simultaneous readout of heat and light signals. We simulate several configurations of a future CUORE-like bolometer array which would utilize these improvements and present the sensitivity reach of a hypothetical next-generation bolometric 0νββ" style="position: relative;" tabindex="0" id="MathJax-Element-3-Frame">0νββ experiment. …

Fluid-Induced Propulsion Of Rigid Particles In Wormlike Micellar Solutions, David A. Gagnon, Nathan C. Keim, Xiaoning Shen, Paulo E. Arratia

Physics

In the absence of inertia, a reciprocal swimmer achieves no net motion in a viscous Newtonian fluid. Here, using tracking methods and birefringence imaging, we investigate the ability of a reciprocally actuated particle to translate through a complex fluid that possesses a network. A geometrically polar particle, a rod with a bead on one end, is reciprocally rotated using magnetic fields. The particle is immersed in a wormlike micellar (WLM) solution that is known to be susceptible to the formation of shear bands and other localized structures due to shear-induced remodeling of its microstructure. Results show that the nonlinearities present …

Phase Transitions In Smectic Liquid Crystal Systems, John Van Atta, Josh Ziegler

Physics

Liquid crystal systems show strong responses to small changes in both temperature and electric field. Changing these conditions can result in phase shifts and other similar behaviors. We study several theoretical models of smectic liquid crystals. The ideas and notation are first developed in basic polynomial models used to describe liquid crystal systems dependent only on temperature. Specifically, smectic-C to smectic-A phase transitions are examined in a fourth-order polynomial model. The bifurcations in the nonlinear equations are shown to correspond to the phase transi- tions in the system. Similar analytic techniques are then applied to a more complex model, based …

Undulatory Swimming In Shear-Thinning Fluids: Experiments With C. Elegans, David A. Gagnon, Nathan C. Keim, Paulo E. Arratia

Physics

The swimming behaviour of microorganisms can be strongly influenced by the rheology of their fluid environment. In this manuscript, we experimentally investigate the effects of shear-thinning viscosity on the swimming behaviour of an undulatory swimmer, the nematode Caenorhabditis elegans. Tracking methods are used to measure the swimmer’s kinematic data (including propulsion speed) and velocity fields. We find that shear-thinning viscosity modifies the velocity fields produced by the swimming nematode but does not modify the nematode’s speed and beating kinematics. Velocimetry data show significant enhancement in local vorticity and circulation, and an increase in fluid velocity near the nematode’s tail, compared …

First Cuore-0 Performance Results And Status Of Cuore Experiment, L. Canonica, D.R. Artusa, F.T. Avignone Iii, N. Chott, R.J. Crewick, H.A. Farach, S. Newman, C. Rosenfeld, J. Wilson, O. Azzolini, A. Camacho, A. De Biasi, G. Keppel, V. Palmieri, C. Pira, V. Rampazzo, T.I. Banks, S.J. Freedman, L. Kogler, Yu. G. Kolomensky, T. O'Donnell, J.L. Ouellet, T. Bloxham, B.K. Fujikawa, K. Han, Y. Mei, G. Bari, M.M. Deninno, N. Moggi, F. Rimondi, S. Zucchelli, J. Beeman, E.E. Haller, F. Bellini, L. Cardani, C. Cosmelli, R. Faccini, F. Ferroni, G. Piperno, I. Dafinei, S. Morganti, F. Orio, C. Tomei, M. Vignati, A. Bersani, S. Didomizio, G. Fernandes, M. Pallavicini, M. Biassoni, C. Brofferio, S. Capelli, M. Carrettoni, D. Chiesa, M. Clemenza, M. Faverzani, E. Ferri, E. Fiorini, A. Giachero, L. Gironi, C. Gotti, C. Miaino, M. Maino, A. Nucciotti, M. Pavan, E. Sala, M. Sisti, L. Zanotti, L. Carbone, O. Cremonesi, V. Datskov, G. Pessina, S. Pirro, E. Previtali, C. Rusconi, F. Terranova, X.Z. Cai, X. Cao, D.Q. Fang, Y.L. Li, Y.G. Ma, W.D. Tian, H.W. Wang, A. Dally, L. Ejzak, K.M. Heeger, D. Lenz, R.H. Maruyama, L. Wielgus, T. Wise, M.A. Franceschi, C. Ligi, T. Napolitano, A. Guiliani, M. Tenconi, T. D. Gutierrez, E.E. Haller, H.Z. Huang, X. Liu, S. Trentalange, B.X. Zhu, R. Kadel, Yu.G. Kolomensky, K. Kazkaz, E.B. Norman, M. Pedretti, S. Sangiorgio, N.D. Scielzo, B.S. Wang, M. Martinez, C. Nones, F. Rimondi, S. Zucchelli, A.R. Smith, L. Taffarello, G. Ventura, A. Woodcraft

Physics

The CUORE (Cryogenic Underground Observatory for Rare Events) experiment will search for neutrinoless double beta decay in 130" style="position: relative;" tabindex="0" id="MathJax-Element-1-Frame">130Te. Observation of the process would unambiguously establish that neutrinos are Majorana particles as well as provide information about the absolute neutrino mass scale and mass hierarchy.The CUORE setup will consist of an array of 988 tellurium dioxide crystals (containing 206 kg of 130" style="position: relative;" tabindex="0" id="MathJax-Element-2-Frame">130Te in total), operated as bolometers at a temperature of ∼" style="position: relative;" tabindex="0" id="MathJax-Element-3-Frame">∼10 mK. The experiment is now under construction at the Gran Sasso National Laboratory in …

Spatially Resolved Spectra Of The “Teacup” Active Galactic Nucleus: Tracing The History Of A Dying Quasar, J.P. Gagne, D.M. Crenshaw, S.B. Kraemer, H.R. Schmitt, W.C. Keel, S. Rafter, T.C. Fischer, K. Schawinski, V.N Bennert

Physics

The Sloan Digital Sky Survey (SDSS) Galaxy Zoo project has revealed a number of spectacular galaxies possessing extended emission-line regions (EELRs), the most famous being Hanny’s Voorwerp galaxy. We present another EELR object discovered in the SDSS endeavor: the Teacup active galactic nucleus (AGN). Nicknamed for its EELR, which has a “handle”-like structure protruding 15 kpc into the northeast quadrant of the galaxy. We analyze the physical conditions of this galaxy with long-slit, ground-based spectroscopy from the Lowell, Lick, and KPNO observatories. With the Lowell 1.8 m Perkin’s telescope we took multiple observations at different offset positions, allowing us to …

Multiple Transient Memories In Experiments On Sheared Non-Brownian Suspensions, Joseph D. Paulsen, Nathan Keim, Sidney R. Nagel

Physics

A system with multiple transient memories can remember a set of inputs but subsequently forgets almost all of them, even as they are continually applied. If noise is added, the system can store all memories indefinitely. The phenomenon has recently been predicted for cyclically sheared non-Brownian suspensions. Here we present experiments on such suspensions, finding behavior consistent with multiple transient memories and showing how memories can be stabilized by noise.

Transcritical Generation Of Nonlinear Internal Waves In The Presence Of Background Shear Flow, Marek Stastna, Ryan Walter

Physics

While the occurrence of large amplitude internal waves in the Earth's natural bodies of water is widely documented, the generation of these waves remains an active area of exploration. We discuss numerical simulations of transcritical flows of a density stratified fluid with a dual focus on the role of a background shear current and transitions of the background current from super to subcritical. We demonstrate that the presence of a background shear can lead to the formation of large quasi-trapped regions of high vorticity over the downstream slope of the topography, but that this vorticity leads to only moderate perturbations …

Laser Frequency Stabilization For Lisa, Andrew B. Parker, Andrew J. Sutton, Glenn De Vine

STAR Program Research Presentations

This research focuses on laser ranging developments for LISA (Laser Interferometer Space Antenna), a planned NASA-ESA gravitational wave detector in space. LISA will utilize precision laser interferometry to track the changes in separation between three satellites orbiting 5 million kilometers apart. Specifically, our goal is to investigate options for laser frequency stabilization. Previous research has shown that an optical cavity system can meet LISA's stability requirements, but these units are large and heavy, adding cost to the implementation. A heterodyne Mach-Zehnder interferometer could be integrated onto LISA’s existing optical bench, greatly reducing the weight, provided the interferometer meets the stability …

Environmental Testing Of Lasers For Jpl's Cold Atom Laboratory, Carey L. Baxter

STAR Program Research Presentations

NASA’s Cold Atom Lab (CAL) is a multi-user facility designed to study ultra-cold quantum gases in the microgravity environment of the International Space Station (ISS). One of the main goals of CAL is to explore the unknown territory of extremely low temperatures—possibly as low as the picokelvin range!—where new and fascinating quantum phenomena can be observed. At such temperatures matter stops behaving as particles and instead becomes macroscopic matter waves. CAL will be remotely controlled to perform a multitude of experiments and is scheduled to launch in 2016. In order to anticipate problems that might occur during and post-launch, including …

A Prototype Microwave Cavity Control Circuit For Use In Next Generation Free Electron Laser, Josh Thompson, Peter Neal Barrina, Jiayi Jiang, Joe Frisch, Steve Smith, Daniel Van Winkle

STAR Program Research Presentations

One of the current programs at SLAC National Accelerator Laboratory is the Linac Coherent Light Source, or LCLS. Using the existing hardware of the last third of their linear accelerator (or “linac”), SLAC has created one of the most energetic X-ray free electron lasers (or “FEL”). Since 2009, LCLS has used this FEL to perform a wide range of experiments across all sciences, most notably ultrafast filming at the molecular scale. As requests for beam-time with this laser increases, SLAC is purposing a linac upgrade to better match this demand. This upgrade, named LCLS-II, will replace existing copper radio frequency …

Maximizing Precision Of Variable Star Photometry With Digital Cameras In Suburban Environments, David Hergesheimer

STAR Program Research Presentations

Photometry is the measure of the brightness of an object. When making such measurements on stars, it is done is units of magnitude, which is on a logarithmic scale with a base of ~2.512. Variable star photometry using a commercially available digital camera is not going to be as accurate and precise as equipment used by astronomers, and because of the logarithmic scale of magnitude used, determining how much of an effect different error reduction strategies have is not straightforward, and is best done experimentally.

My research is conducting photometry on variable stars (changing brightness) with a digital camera, and …

Initial Performance Of The Cuore-0 Experiment, D.R. Artusa, F.T. Avignone Iii, O. Azzolini, M. Balata, T.I. Banks, G. Bari, J. Beeman, F. Bellini, A. Bersani, M. Biassoni, C. Brofferio, C. Bucci, X.Z. Cai, L. Canonica, X.G. Cao, S. Capelli, L. Carbone, L. Cardani, M. Carrettoni, N. Casali, D. Chiesa, N. Chott, M. Clemenza, C. Cosmelli, O. Cremonesi, R.J. Creswick, I. Dafinei, A. Dally, V. Datskov, M.M. Deninno, S. Di Domizio, M.L. Di Vacri, L. Ejzak, D.Q. Fang, H.A. Farach, M. Facerzani, G. Fernandes, E. Ferri, F. Ferroni, E. Fiorini, S.J. Freedman, B.K. Fujikawa, A. Giachero, L. Gironi, A. Guiliani, J. Goett, P. Gorla, C. Gotti, T. D. Gutierrez, E.E. Haller, K. Han, K.M. Heeger, R. Hennings-Yeomans, H.Z. Huang, R. Kadel, K. Kazkaz, G. Keppel, Yu.G. Kolomensky, Y.L. Li, K.E. Lim, X. Liu, Y.G. Ma, C. Maiano, M. Maino, M. Martinez, R.H. Maruyama, Y. Mei, N. Moggi, S. Morganti, S. Nisi, C. Nones, E.B. Norman, A. Nucciotti, T. O'Donnell, F. Orio, D. Orlandi, J.L. Ouellet, M. Pallavicini, V. Palmieri, L. Pattavina, M. Pavan, M. Pedretti, G. Pessina, V. Pettinacci, G. Piperno, S. Pirro, E. Previtali, C. Rosenfeld, E. Sala, S. Sangiorgio, N.D. Scielzo, M. Sisti, A.R. Smith, L. Taffarello, M. Tenconi, F. Terranova, W.D. Tian, C. Tomei, S. Trentalange, G. Ventura, M. Vignati, B.S. Wang, H.W. Wang, L. Wielgus, J. Wilson, L.A. Winslow, T. Wise, L. Zanotti, C. Zarra, B.X. Zhu, S. Zucchelli

Physics

CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide bolometers to search for neutrinoless double-beta decay of 130Te" style="position: relative;" tabindex="0" id="MathJax-Element-1-Frame">130Te. We present the first data analysis with 7.1kg⋅y" style="position: relative;" tabindex="0" id="MathJax-Element-2-Frame">7.1kg⋅y of total TeO2" style="position: relative;" tabindex="0" id="MathJax-Element-3-Frame">TeO2 exposure focusing on background measurements and energy resolution. The background rates in the neutrinoless double-beta decay region of interest (2.47 to 2.57MeV" style="position: relative;" tabindex="0" id="MathJax-Element-4-Frame">2.57MeV) and in the α" style="position: relative;" tabindex="0" id="MathJax-Element-5-Frame">α background-dominated region (2.70 to 3.90MeV" style="position: relative;" tabindex="0" id="MathJax-Element-6-Frame">3.90MeV) have been measured to be 0.071±0.011" style="position: …

Particle Image Velocimetry Of Transverse Jets In Crossflow, Jesse K. Tsai, Kayla Kuzmich, David Forliti, Kriss Vanderhyde, Nils Sedano

STAR Program Research Presentations

The jet in crossflow (JICF) has been an ongoing study for the past several decades with applications in the field of fluid mechanics. This particular flow field produces vortical structures tied to the entrainment and mixing of two separate fluids. Research of the JICF seeks to determine a model and trajectory scaling law for future designs. This will help future designers to optimize the mixing and homogeneity of the two fluids to decrease emissions from pollutants, make ignition easier, and improve combustion efficiency of rockets.

Our experiment will employ Particle Image Velocimetry (PIV) to determine the fluid motion of the …

Tuffoam Density Variation Through Radiography, Sergio Contreras Esquivel

STAR Program Research Presentations

TufFoam is a low density, high impact tolerant polyurethane foam with good high voltage breakdown developed at the Sandia National Laboratories. Identically shaped samples have been produced with various formulations and production conditions. Eight different variables were studied. Our aim is to compare the density variation of the material when produced and processed under distinct conditions. The density of TufFoam is determined using radiographic imaging. We extract the foam density by fitting the radiographic density of each step in a plastic step wedge with 10 steps from 0.1 to 1.0 inches and applying the resulting equation to convert each pixel …

Exploring Soil Moisture Protocol Alternatives For The Classroom Setting, Garrett Smith

STAR Program Research Presentations

Climate change poses a direct threat to future water resources but current climate models suffer from uncertainties regarding the availability of regional water. SMAP or the Soil Moisture Active Passive mission seeks to make improvements to climate models by taking highly accurate, high resolution measurements of global soil moisture. To engage students around the world in a collection of meaningful data that may support the SMAP satellite mission, the Global Learning and Observations to Benefit the Environment program or GLOBE, has forged a partnership with NASA and JPL. GLOBE brings the power of citizen science to the SMAP mission, empowering …

Does A Plastron Improve Heat Transfer?, Madani A. Khan, Jeffrey Alston, Andrew Guenthner

STAR Program Research Presentations

Superamphiphobic surfaces strongly repel both water and oils. In this work, aluminum coupons are processed by sanding with various grit of sand paper to impart microscale roughness. Subsequent submersion of the aluminum substrate in boiling water grows nanoscale grass-like structures. The oxide layer of Al is slightly soluble in water. During a fast diffusion/equilibrium, Al₂O₃ nanograss grows on the surface. A low energy coating is then deposited on the surface. The micro and nanoscale features create re-entrant structures that trap air enabling contact liquid to be in a Cassie-Baxter state. Superamphiphobicity of the samples were confirmed by …

Calculating And Visualizing The Density Of States For Simple Quantum Mechanical Systems, Declan Mulhall, Matthew J. Moelter

Physics

We present a graphical approach to understanding the degeneracy, density of states, and cumulative state number for some simple quantum systems. By taking advantage of basic computing operations, we define a straightforward procedure for determining the relationship between discrete quantum energy levels and the corresponding density of states and cumulative level number. The density of states for a particle in a rigid box of various shapes and dimensions is examined and graphed. It is seen that the dimension of the box, rather than its shape, is the most important feature. In addition, we look at the density of states for …

Viscosity Dependence Of Faraday Wave Formation Thresholds, Lisa M. Slaughter

Symposium

This experiment uses an electromagnetic shaker to produce standing wave patterns on the surface of a vertically oscillating sample of silicon liquid. These surface waves, known as Faraday waves, form shapes such as squares, lines, and hexagons. They are known to be dependent upon the frequency and amplitude of the forcing as well as on the viscosity and depth of the liquid in the dish. At a depth of 4mm and for various silicon liquids having kinematic viscosities of 10, 20, and 38 cSt, we determined the acceleration at which patterns form for frequencies between 10 and 60 Hz. For …

Connecting Wind-Driven Upwelling And Offshore Stratification To Nearshore Internal Bores And Oxygen Variability, Ryan K. Walter, C. Brock Woodson, Paul R. Leary, Stephen G. Monismith

Physics

This study utilizes field observations in southern Monterey Bay, CA, to examine how regional-scale upwelling and changing offshore (shelf) conditions influence nearshore internal bores. We show that the low-frequency wind forcing (e.g., upwelling/relaxation time scales) modifies the offshore stratification and thermocline depth. This in turn alters the strength and structure of observed internal bores in the near-shore. An internal bore strength index is defined using the high-pass filtered potential energy density anomaly in the nearshore. During weak upwelling favorable conditions and wind relaxations, the offshore thermocline deepens. In this case, both the amplitude of the offshore internal tide and the …

Nonlinear Internal Waves, Internal Bores, And Turbulent Mixing In The Nearshore Coastal Environment, Ryan K. Walter

Physics

The nearshore coastal environment is generally taken to be one of the most productive and ecologically important parts of the ocean. The nearshore is also a complex environment from a physical standpoint, due in large part to the widespread and often irregular occurrence of nonlinear internal waves (NLIWs) that frequently appear more bore-like than wave-like. Indeed, this region of the ocean can be thought of as the “swash zone” for larger-scale internal wave fields on the continental shelf. These nearshore NLIWs and bores have considerable implications for the cross-shelf exchange and transport of nutrients, sediments, contaminants, larvae, and other scalars; …

Rubidium-Based Atomic Clock, Kate Miles

Physics

In this paper we will explore the process of building an atomic clock from a function generator, go into an in-depth introductory discussion of the Datum LPRO, and examine how rubidium function generators work.

Introduction To Ligo And An Experiment Regarding The Quality Factor Of Crystalline Silicon, Edward Taylor

Physics

Third generation LIGO detectors will be limited by thermal noise at a low frequency band where gravitational wave signals are expected to exist. A large contribution to thermal noise is caused by internal friction of the mirror and suspension elements. In order to meet the quantum mechanical sensitivity limits of the detector, it will be necessary to further push down the contribution of thermal noise. Future detectors will require new materials with extremely high mechanical quality. Silicon at cryogenic temperatures shows the promise to provide the required mechanical quality due to its vanishing expansion coefficient at 120 K. The fluctuation …

Exploring The Relationship Between A Fluid Container's Geometry And When It Will Balance On Edge, Ryan J. Moriarty

Physics

At some point while consuming a beverage, many people will idly try to balance its container on edge. The act itself is physically straightforward, merely involving the system's center of mass and achieving a static equilibrium between the opposing torques caused by gravity and the normal force between the container and the surface on which it balances. Further analysis of the act, however, illuminates the richness of the exercise.

These nuances are apparent even in simplified two-dimensional models because of the depth of the relationship between a container's geometry and achieving balance. The purpose of such analysis is threefold: first, …

Optical Properties Of De Vries Liquid Crystals And A Look At Ultra Thin Freely Suspended Smectic Films, Joshua P. Fankhauser

Physics

Liquid crystals exist as a fourth state of matter. They are anisotropic and due to this order, they affect light that passes through them, making them ideal candidates for optical study. By employing a basic technique for measuring a liquid crystal's birefringence and tilt angle, one is able to study a number of other properties such as the electroclinic effect. In addition, smectic liquid crystals have been studied intently because of their ability to create stable ultra-thin films of quantized layer thickness. These thin films have been studied due to the fact that they are an ideal system for investigating …

Laser Doppler Velocimetry: Flow Measurement Using A Digital Micromirror Device, Dawei Kuo

Physics

In this experiment we utilize a Texas Instruments Digital Micromirror Device to impart a phase shift to the beams of a laser Doppler velocimeter. The advantages of this approach include low cost, low power consumption, a precisely known phase-stepping frequency, and the capability of working with a broad range of optical wavelengths. The velocities measured with the set up shown here are of order 1 cm/s.