Physics Commons^™

Structure And Dynamics Of Self-Assembling Colloidal Monolayers In Oscillating Magnetic Fields, Alison E. Patteson (Koser), Nathan C. Keim, Paulo E. Arratia

Physics - All Scholarship

Many fascinating phenomena such as large-scale collective flows, enhanced fluid mixing, and pattern formation have been observed in so-called active fluids, which are composed of particles that can absorb energy and dissipate it into the fluid medium. For active particles immersed in liquids, fluid-mediated viscous stresses can play an important role on the emergence of collective behavior. Here, we experimentally investigate their role in the dynamics of self-assembling magnetically driven colloidal particles which can rapidly form organized hexagonal structures. We find that viscous stresses reduce hexagonal ordering, generate smaller clusters, and significantly decrease the rate of cluster formation, all while …

Precision Measurement Of The Lambda_B Baryon Lifetime, Bilas Kanti Pal

Dissertations - ALL

The ratio of the Lambda_b baryon lifetime to that of the B0 meson is measured using data corresponding to an integrated luminosity of 3.0 /fb collected with the LHCb detector using pp collisions at the LHC. The Lambda_b baryon is observed in the decay mode Lambda_b ->J/psi p K-, while the B0 meson decay used is the well known B0->J/psi pi+ K- mode, where the pi+K- mass is consistent with that of the K*0(892) meson. The ratio of lifetimes is measured to be 0.971+/-0.007+/-0.005, in agreement with theoretical expectations based on the heavy quark expansion. Using previous determinations …

Measurement Of The Cp Violating Asymmetry A^S_Sl Using Bs0->(Ds->Phi Pi) Mu Nu, Alessandra Borgia

Dissertations - ALL

The time-integrated measurement of the semileptonic CP violating asymmetry, as_sl, with data acquired at the Large Hadron Collider with the LHCb experiment is presented. This measurement can help physicists understand some peculiarities in the Standard Model, which is the fundamental framework of knowledge of the universe. Should this asymmetry diverge from zero, new physics may be a main motivator. Using 1 fb-1 of collected data in 2011 with proton-proton collisions at a center-of-mass energy of 7 TeV, the measured value of as_sl presented is (-0.06 ± 0.50 ± 0.36)%, where the first uncertainty is statistical and the …

Research And Development Of The Positron Damping Rings For The Proposed International Linear Collider And At Cern In Geneva, Switzerland For The Large Hadron Collider Atlas Experiment's Integrated Simulation Framwork, Ryan Badman

Honors Capstone Projects - All

The topic of part I of my capstone is electron clouds, studied in the Cornell synchrotron accelerator. Electron clouds are an important phenomenon to study in circular particle accelerators such as the Large Hadron Collider (LHC), the Cornell synchrotron, and the damping ring for the proposed International Linear Collider (ILC). Low energy background electrons are normally present in high energy accelerators and are often not detrimental to beam performance, but certain operation conditions cause them to interact strongly with the beam, as was first observed in the 1980s in positron storage rings. The generation and amplification of the electron cloud …

Influence Of Genetic Variation On Birth Defects In Caenorhabditis Elegans, Daniel Robert Kepple

Honors Capstone Projects - All

In my Renee Crown Honors Capstone project, I studied how genetic variation influences birth defects that cause death in C. elegans embryos. I performed high-throughput hatching assay experiments of recombinant inbred advance intercross lines of C. elegans. These lines are genetically distinct from each other. I found significant variation in birth defects causing embryo death in these recombinant inbred advanced intercross lines. My results give evidence that gene interaction may play a significant role in causing birth defects resulting in death. My data also provides a starting point for studies making statistical arguments linking these birth defects to specific …

Where Does The Water Come From? A Temporal Geochemical Characterization Of Water Sources In The Lives Of Storms, Mallory Ringham

Honors Capstone Projects - All

An analysis of the ion chemistry, δ¹⁸O, and δ²H values of precipitation may allow for the characterization of their water sources. As water evaporates, it retains a signature of its source in the ions that it carries and in the amount of fractionation of the oxygen and hydrogen isotopes. Precipitation samples for coastal, lake effect, and continental sources were collected over the months of October- January in Syracuse, New York throughout the duration of each storm, including one hurricane, one thunderstorm, two lake effect snowstorms, and seven rain events. These samples were run through IC, ICP-OES, …

Molecular Sensing With Protein And Solid-State Nanopores, David John Niedzwiecki

Physics - Dissertations

In the past 15 years nanopore sensing has proven to be a successful method for probing a variety of molecules of biological interest, such as DNA, RNA and proteins. Of particular appeal is this technique's ability to probe these molecules without the need for chemical modification or labeling, to do so at physiological conditions, and to probe single molecules at a time, allowing the possibility for results masked in bulk measurements to come to light. In this thesis these advantageous properties will be used in work on both a synthetic (solid-state) nanopore system and an engineered biological nanopore. I will …

Particle Physics In The Lhc Era, Don Bunk

Physics - Dissertations

During the past 100 years experimental particle physicists have collected an impressive amount of data. Theorists have also come to understand this data extremely well. It was in the first half of the 20th century the efforts of the early pioneers of quantum mechanics laid the ground work for this understanding: quantum field theory. Through the tireless efforts of researchers during the later half of the 20th century many ideas came together to form what we now call the Standard Model (SM) of particle physics. Finally, it was through the ideas of the renormalization group and effective field theory that …

First Leptonic Probe Of Neutron Radii In Lead At Low-Q2, Chun-Min Jen

Physics - Dissertations

Over the past decade, in Hall-A of the Thomas Jefferson National Accelerator Facility (TJNAF), both the HAPPEX and PREx collaborations have carried out various high-precision polarized elastic electron scattering experiments to explore the nuclear structure, the nucleon form factor and the weak charge of proton and electron. They have done so through the technique of the parity-violating asymmetry measurement with limited theoretical uncertainties. My dissertation focuses on the study of nuclear structure, namely the thickness of the neutron skin, using elastic electron scattering experiments.

The direct measurement of the thickness of the neutron skin in heavy nuclei, where neutron are …

Research And Development Of The Positron Damping Rings For The Proposed International Linear Collider, And At Cern In Geneva, Switzerland For The Large Hadron Collider Atlas Experiment's Integrated Simulation Framework, Ryan Badman

Honors Capstone Projects - All

Abstract not available. Please download the full Capstone for abstract.

Measuring Material Relaxation And Creep Recovery In A Microfluidic Device, Alison E. Patteson (Koser), Lichao Pan, Nathan C. Keim, Paulo E. Arratia

Physics - All Scholarship

We present a novel method of testing creep recovery in a microfluidic device. This method allows for the measurement of relaxation time of fluids at low strain. After applying a steady pressure-driven flow along a microchannel, the pressure is released and the fluid is allowed to relax and come to rest. Local strains are observed via the time-dependent velocity profiles and are fit to a general viscoelastic model to obtain the fluids' relaxation times. The use of polymeric solutions of various molecular weights allows for the observation of time scales for strains ranging from 0.01 to 10. Results are consistent …

Multiple Transient Memories In Sheared Suspensions: Robustness, Structure, And Routes To Plasticity, Nathan C. Keim, Joseph D. Paulsen, Sidney R. Nagel

Physics - All Scholarship

Multiple transient memories, originally discovered in charge-density-wave conductors, are a remarkable and initially counterintuitive example of how a system can store information about its driving. In this class of memories, a system can learn multiple driving inputs, nearly all of which are eventually forgotten despite their continual input. If sufficient noise is present, the system regains plasticity so that it can continue to learn new memories indefinitely. Recently, Keim and Nagel [Phys. Rev. Lett. 107, 010603 (2011)] showed how multiple transient memories could be generalized to a generic driven disordered system with noise, giving as an example simulations of a …

Approach And Coalescence Of Liquid Drops In Air, Joseph Paulsen

Physics - All Scholarship

The coalescence of liquid drops has conventionally been thought to have just two regimes when the drops are brought together slowly in vacuum or air: a viscous regime corresponding to the Stokes-flow limit and a later inertially dominated regime. Recent work found that the Stokes-flow limit cannot be reached in the early moments of coalescence, because the inertia of the drops cannot be neglected then. Instead, the drops are described by an "inertially limited viscous" regime, where surface tension, inertia, and viscous forces all balance. The dynamics continue in this regime until either viscosity or inertia dominate on their own. …

Measurement Of The Semileptonic Cp Violating Asymmetry A Sl S In B S Decays And The D S + -- D S - Production Asymmetry In 7 Tev Pp Collisions, Zhou Xing

Physics - Dissertations

The large hadron collider (LHC) at the European Organization for Nuclear Research (CERN) in Geneva is the world's largest and highest-energy particle accelerator. It is located in a tunnel with a circumference of 27 kilometers (17 miles) whose synchrotron is designed to mainly collide opposing particle beams of protons with energy up to 7 TeV in 2011 and 8 TeV in 2012. LHC is designed to address some of the fundamental open questions in physics regarding the basic laws governing the interactions and forces among the elementary particles. Among the four major experiments at LHC: A Toroidal LHC Apparatus (ATLAS), …

Light Trapping For Silicon Solar Cells: Theory And Experiment, Hui Zhao

Physics - Dissertations

Crystalline silicon solar cells have been the mainstream technology for photovoltaic energy conversion since their invention in 1954. Since silicon is an indirect band gap material, its absorption coefficient is low for much of the solar spectrum, and the highest conversion efficiencies are achieved only in cells that are thicker than about 0.1 mm. Light trapping by total internal reflection is important to increase the optical absorption in silicon layers, and becomes increasingly important as the layers are thinned. Light trapping is typically characterized by the enhancement of the absorptance of a solar cell beyond the value for a single …