Physics Commons^™

Inductive Metal Identification, Paul Maggi

Electrical Engineering

This project focuses on creating a device to differentiate between various types of metals via magnetic induction. Magnetic induction is used because it is both non-optical and non-contact. It achieves this by generating a varying magnetic field, which induces eddy currents in the metal. These eddy currents produce small disturbances in the surrounding magnetic field, which can be sensed with Hall Effect Sensors (HES). The primary challenge in this project was generating a sufficiently strong magnetic field to detectable disturbances. In order to achieve better results, a stronger magnetic field must be used as well as more sensitive Hall Effect …

Day/Night Band Imager For A Cubesat, Eric Stanton

Electrical Engineering

Day/Night Band (DNB) earth sensing and meteorological systems like the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) provide visible wavelength imagery 24 hours a day that is used primarily for cloud imaging in support of weather forecasting. This paper describes a compact push-broom imager that meets low light imaging requirements for DMSP OLS and the NOAA/NASA Joint Polar Satellite System (JPSS) as documented in the Integrated Operational Requirements Document [1] (IORD) including the imager design, system level concepts of operation for data collection, radiometric and spatial calibration, and data transmission to Earth. This small, lightweight imager complies with …

Point-Spread Function Assessment Of Sg-Dbr Based Swept Source For Oct Imaging, David Wilkey Gilbert

Master's Theses

Swept Source Optical Coherence Tomography (SS-OCT) is a medical imaging technique that requires high repetition rate, widely-tunable coherent laser sources. Sampled grating distributed Bragg reflector (SG-DBR) lasers are proven in telecom applications and are expected to fulfill the requirements for SS-OCT at a significantly lower cost than alternative solutions.

Constructed entirely on a semiconductor substrate, SG-DBR lasers require four synchronized waveforms to modulate the output wavelength and intensity. Because of this unique tuning mechanism, there are a number of systematic and noise sources that can affect the quality of the OCT point-spread function (PSF). Based on these noise sources, software …

Approaches To Control Nitrate Pollution In The San Joaquin Watershed, Misgana K. Muleta, Stephen Clayton

Physics

Modeling of the San Joaquin valley using SWAT can give a comprehensive overview of hydrologic traits of the San Joaquin River and its tributaries, specifically for nutrients like nitrate. The San Joaquin valley is a site of intense modeling interest and policy making, as the San Joaquin River joins the Sacramento River to feed into the Delta. The environmental impact of dissolved oxygen on aquatic life on the Delta is a particularly key concern (Quinn 2000). The San Joaquin watershed also represents considerable investment in agriculture on the valley floor and has been studied for nitrate, sediment, and salinity concerns …

Lhc One-Turn Delay Feedback Commissioning, T. Mastoridis, P. Baudrenghien, J. Molendijk

Physics

The LHC One-Turn delay FeedBack (OTFB) is an FPGA based feedback system part of the LHC cavity controller, which produces gain only around the revolution frequency (frev = 11.245 kHz) harmonics. As such, it helps reduce the transient beam loading and effective cavity impedance. Consequently, it increases the stability margin for Longitudinal Coupled Bunch Instabilities driven by the cavity impedance at the fundamental and allows reliable operation at higher beam currents. The OTFB was commissioned on all sixteen cavities in mid-October 2011 and has been used in operation since. The commissioning procedure and algorithms for setting-up are presented. The resulting …

Proposal For An Rf Roadmap Towards Ultimate Intensity In The Lhc, P. Baudrenghien, T. Mastoridis

Physics

The LHC currently operates with 1380 bunches at 50 ns spacing and 1.4 1011 p per bunch (0.35A DC). In this paper the RF operation with ultimate bunch intensity (1.7 1011 p per bunch) and 25 ns spacing (2808 bunches per beam) summing up to 0.86A DC is presented. With the higher beam current, the demanded klystron power will be increased and the longitudinal stability margin reduced. One must also consider the impact of a klystron trip (voltage and power transients in the three turns latency before the beam is actually dumped). In this work a scheme is proposed that …

Evaluating Alternative Hydraulic Solutions To Limit Nutrient Contamination Of An Aquifer In Southern California Read More: Http://Ascelibrary.Org/Doi/Abs/10.1061/9780784412312.009, Misgana K. Muleta, Jake M. Perry

Physics

Many small communities depend on groundwater sources for drinking water and they often use septic tanks for wastewater treatment and disposal. Nitrate and other pollutants leaking from poorly designed septic tank systems can percolate to the aquifers and alter quality of the groundwater. This study describes a groundwater model developed using Visual MODFLOW for an aquifer that is used as a water supply source for the communities of Beaumont and Cherry Valley, CA. The aquifer has been contaminated by nitrates leaking from septic tank systems. The model will assist in clarifying the extent of interactions between nitrate pollutants, percolation from …

Uncertainty Analysis And Calibration Of Swmm Using A Formal Bayesian Methodology Read More: Http://Ascelibrary.Org/Doi/Abs/10.1061/9780784412312.060, Misgana K. Muleta

Physics

Importance of uncertainty analysis (UA) to estimate the degree of reliability associated with model predictions is being understood. Consequently, literature that describes various Bayesian methods for the assessment of parameter and model predictive uncertainty has been steadily rising. Applications dealing with urban stormwater management are, however, very limited. This study demonstrates successful application of a formal Bayesian methodology for UA of the U.S. EPA Stormwater Management Model (SWMM), a widely used urban stormwater management model, and illustrates the methodology using a highly urbanized watershed in southern California. DREAM_(ZS), a recently developed effective and efficient sampling algorithm, and a …

A Formal, Bayesian Approach For Uncertainty Analysis Of A Watershed Model, Misgana K. Muleta

Physics

Uncertainty analysis (UA) has received substantial attention in water resources during the last decade. Bayesian approaches are often preferred for UA. This study describes a formal Bayesian approach for the assessment of parameter uncertainty and predictive uncertainty using a spatially distributed hydrologic model and will demonstrate its application using data from a well monitored experimental watershed. A Markov-Chain Monte Carlo (MCMC) scheme has been used to sample posterior parameter distributions. A formal, flexible likelihood function that explicitly accounts for heteroscedasticity, temporal correlation and non-normality of simulation residuals has been used to describe closeness of the simulated and observed streamflow. Performance …

Computing Accurate Age And Distance Factors In Cosmology, Jodi L. Christiansen, Andrew Siver

Physics

As the universe expands astronomical observables such as brightness and angular size on the sky change in ways that differ from our simple Cartesian expectation. We show how observed quantities depend on the expansion of space and demonstrate how to calculate such quantities using the Friedmann equations. The general solution to the Friedmann equations requires a numerical solution which is easily coded in any computing language (including EXCEL). We use these numerical calculations in four student projects that help to build their understanding of high-redshift phenomena and cosmology. Instructions for these projects are available as supplementary materials.

The Quantum Mechanics Of Supersymmetry, Joshua Gearhart

Physics

No abstract provided.

Building And Characterization Of Laser Diodes As Well As System Design Of A Dual Wavelength Fabry-Perot Interferometer, Nicholas Czapla

Physics

No abstract provided.

Techniques To Characterize Vapor Cell Performance For A Nuclear-Magnetic-Resonance Gyroscope, James Julian Mirijanian

Master's Theses

Research was performed to improve the procedures for testing performance parameters of vapor cells for a nuclear-magnetic-resonance gyroscope. In addition to summarizing the theoretical infrastructure of the technology, this research resulted in the development and successful implementation of new techniques to characterize gyro cell performance.

One of the most important parameters to measure for gyro performance is the longitudinal spin lifetime of polarized xenon atoms in the vapor cell. The newly implemented technique for measuring these lifetimes matches results from the industry standard method to within 3.5% error while reducing the average testing time by 76% and increasing data resolution …

Search For Double-Β Decay Of 130te To The First 0+ Excited State Of 130xe With The Cuoricino Experiment Bolometer Array, E. Andreotti, C. Arnaboldi, F.T. Avignone Iii, M. Balata, I. Bandac, M. Barucci, J.W. Beeman, F. Bellini, C. Brofferio, A. Bryant, C. Bucci, L. Canonica, S. Capelli, L. Carbone, M. Carrettoni, M. Clemenza, O. Cremonesi, R.J. Creswick, S. Di Domizio, M.J. Dolinski, L. Ejzak, R. Faccini, H.A. Farach, E. Ferri, E. Fiorini, L. Foggetta, A. Giachero, L. Gironi, A. Giuliani, P. Gorla, E. Guardincerri, T.D. Gutierrez, E.E. Haller, K. Kazkaz, L. Kogler, S. Kraft, C. Maiano, C. Martinez, M. Martinez, R.H. Maruyama, S. Newman, S. Nisi, C. Nones, E.B. Norman, A. Nucciotti, F. Orio, M. Pallavicini, V. Palmieri, L. Pattavina, M. Pavan, M. Pedretti, G. Pessina, S. Pirro, E. Previtali, L. Risegari, C. Rosenfeld, C. Rusconi, C. Salvioni, S. Sangiorgio, D. Schaeffer, N.D. Scielzo, M. Sisti, A.R. Smith, C. Tomei, G. Ventura, M. Vignati

Physics

The CUORICINO experiment was an array of 62 TeO2 single-crystal bolometers with a total 130Te mass of 11.3kg. The experiment finished in 2008 after more than 3 yr of active operating time. Searches for both 0ν and 2ν double-β decay to the first excited 0+ state in 130Xe were performed by studying different coincidence scenarios. The analysis was based on data representing a total exposure of N(130Te)⋅t=9.5×1025yr. No evidence for a signal was found. The resulting lower limits on the half-lives are T2ν12(130Te→130Xe∗)>1.3×1023yr (90% C.L.), and T0ν12(130Te→130Xe∗)>9.4×1023yr (90% CL).

Reflections On The Forum At Forty, David Hafemeister

Physics

No abstract provided.

The Lick Agn Monitoring Project 2011: Recalibrating Single-Epoch Virial Black Hole Mass Estimates, Daeseong Park, Jong-Hak Woo, Tommaso Treu, Aaron J. Barth, Misty C. Bentz, Vardha N. Bennert, Gabriela Canalizo, Alexei V. Filippenko, Elinor Gates, Jenny E. Greene, Matthew A. Malkan, Jonelle Walsh

Physics

We investigate the calibration and uncertainties of black hole (BH) mass estimates based on the single-epoch (SE) method, using homogeneous and high-quality multi-epoch spectra obtained by the Lick Active Galactic Nucleus (AGN) Monitoring Project for nine local Seyfert 1 galaxies with BH masses <10⁸ M _☉. By decomposing the spectra into their AGNs and stellar components, we study the variability of the SE Hβ line width (full width at half-maximum intensity, FWHM_Hβ or dispersion, σ_Hβ) and of the AGN continuum luminosity at 5100 Å (L ₅₁₀₀). From the distribution of the "virial products" ( …

The Galaxy Zoo Survey For Giant Agn-Ionized Clouds: Past And Present Black Hole Accretion Events, William C. Keel, Drew Chojnowski, Vardha N. Bennert, Kevin Schawinski, Chris J. Lintott, Stuart Lynn, Anna Pancoast, Chelsea Harris, A. M. Nierenberg, Alessandro Sonnenfeld, Richard Proctor

Physics

Some active galactic nuclei (AGN) are surrounded by extended emission-line regions (EELRs), which trace both the illumination pattern of escaping radiation and its history over the light travel time from the AGN to the gas. From a new set of such EELRs, we present evidence that the AGN in many Seyfert galaxies undergo luminous episodes 0.2–2 ×105 years in duration. Motivated by the discovery of the spectacular nebula known as Hanny’s Voorwerp, ionized by a powerful AGN which has apparently faded dramatically within ≈ 105 years, Galaxy Zoo volunteers have carried out both targeted and serendipitous searches for similar emission-line …

Novel Magnetite-Producing Magnetotactic Bacteria Belonging To The Gammaproteobacteria, Christopher T. Lefèvre, Nathan Viloria, Marian L. Schmidt, Mihály Pósfai, Richard B. Frankel, Dennis A. Bazylinski

Physics

Two novel magnetotactic bacteria (MTB) were isolated from sediment and water collected from the Badwater Basin, Death Valley National Park and southeastern shore of the Salton Sea, respectively, and were designated as strains BW-2 and SS-5, respectively. Both organisms are rod-shaped, biomineralize magnetite, and are motile by means of flagella. The strains grow chemolithoautotrophically oxidizing thiosulfate and sulfide microaerobically as electron donors, with thiosulfate oxidized stoichiometrically to sulfate. They appear to utilize the Calvin–Benson–Bassham cycle for autotrophy based on ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) activity and the presence of partial sequences of RubisCO genes. Strains BW-2 and SS-5 biomineralize chains of octahedral …

Forum History At Forty (2012), David Hafemeister

Physics

Physics is a major component of many of society's difficult issues: nuclear arms and their proliferation, energy shortages and energy impacts, climate change, and technical innovation. Because physics principles underlie so many of these societal issues and because physics offers a way to quantify some aspects of them, members of the American Physical Society (APS) should be encouraged to understand, analyze and debate them. This is precisely why APS members formed the Forum on Physics and Society (FPS). To those of us who have been involved in FPS affairs for a long time, it seems like only yesterday that we …

Very Early Ultraviolet And Optical Observations Of The Type Ia Supernova 2009ig, Ryan J. Foley, P. J. Challis, A. V. Filippenko, M. Ganeshalingam, W. Landsman, W. Li, G. H. Marion, J. M. Silverman, R. L. Beaton, V. N. Bennert, S. B. Cenko, M. Childress, P. Guhathakurta, L. Jiang, J. S. Kalirai, R. P. Kirshner, A. Stockton, E. J. Tollerud, J. Vinkó, J. C. Wheeler, J.-H. Woo

Physics

Supernova (SN) 2009ig was discovered 17 hr after explosion by the Lick Observatory Supernova Search, promptly classified as a normal Type Ia SN (SN Ia), peaked at V = 13.5 mag, and was equatorial, making it one of the foremost SNe for intensive study in the last decade. Here, we present ultraviolet (UV) and optical observations of SN 2009ig, starting about 1 day after explosion until around maximum brightness. Our data include excellent UV and optical light curves, 25 premaximum optical spectra, and 8 UV spectra, including the earliest UV spectrum ever obtained of an SN Ia. SN 2009ig is …

Exploring The Physics With Computer Animation, T. J. Bensky

Physics

No abstract provided.

Review Of Ola Dahlman Et Al., Detect And Deter: Can Countries Verify The Nuclear Test Ban, David Hafemeister

Physics

No abstract provided.

Fluid Elasticity Can Enable Propulsion At Low Reynolds Number, Nathan C. Keim, Mike Garcia, Paulo E. Arratia

Physics

Conventionally, a microscopic particle that performs a reciprocal stroke cannot move through its environment. This is because at small scales, the response of simple Newtonian fluids is purely viscous and flows are time-reversible. We show that by contrast, fluid elasticity enables propulsion by reciprocal forcing that is otherwise impossible. We present experiments on rigid objects actuated reciprocally in viscous fluids, demonstrating for the first time a purely elastic propulsion set by the object’s shape and boundary conditions. We describe two different artificial “swimmers” that experimentally realize this principle.

Optical Mode Pattern Study Of Gan Based Leds With And Without Nanoscale Top Grating, Gregory Chavoor

Electrical Engineering

This study analyzes optical confinement factor and light emitting mode order for three different GaN LEDs: a conventional LED, thin Film LED, and thin Film LED with a photonic crystal (PhC) grating. For the first structure, we increase the thickness of Al_xGa_1-xN from 0 to 600nm, alter the x composition in Al_xGa_1-xN from 0.05 to 0.2 in steps of 0.05, and adjust the p-GaN and n-GaN thicknesses each from 0 to 200nm. For the second structure, we alter the n-GaN substrate thickness from 300-1000nm in steps of 100nm and 1000-4000nm in steps …