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Articles 1 - 30 of 42
Full-Text Articles in Physics
Jitter Impact On Clock Distribution In Lhc Experiments, S. Baron, Themis Mastoridis, J. Troska, P. Baudrenghien
Jitter Impact On Clock Distribution In Lhc Experiments, S. Baron, Themis Mastoridis, J. Troska, P. Baudrenghien
Physics
The LHC Bunch Clock is one of the most important accelerator signals delivered to the experiments. Being directly derived from the Radio Frequency driving the beams in the accelerator by a simple division of its frequency by a factor of 10, the Bunch Clock signal represents the frequency at which the bunches are crossing each other at each experiment. It is thus used to synchronize all the electronics systems in charge of event detection. Its frequency is around 40.079 MHz, but varies with beam parameters (energy, particle type, etc) by a few hundreds of Hz. The present paper discusses the …
Aspects Of General Relativity In 1+1 Dimensions, Richard D. Mellinger Jr
Aspects Of General Relativity In 1+1 Dimensions, Richard D. Mellinger Jr
Physics
What would be the properties of a universe with only one spatial dimension and one time dimension? General relativity in 1+1 dimensions is unique since the two curvature terms in the Einstein field equations cancel. This makes the Einstein field equations algebraic rather than differential equations. This special feature can make 1+1 dimensionality attractive as an instructional tool to simplify the mathematics that many beginners find opaque. We explore the implications and features of the Einstein field equations in 1+1 dimensions and find they provide a surprisingly rich and interesting model. We then study an alternate theory and its implications …
Investigation Of Optical Dipole Traps For Trapping Neutral Atoms For Quantum Computing, Danielle May
Investigation Of Optical Dipole Traps For Trapping Neutral Atoms For Quantum Computing, Danielle May
Physics
No abstract provided.
Building An Alpha Spectrometer For The Cuore Collaboration, David J. Miller
Building An Alpha Spectrometer For The Cuore Collaboration, David J. Miller
Physics
This paper will give the reader a brief introduction to the Standard Model, Neutrinoless Double Beta Decay (0νββ), and the CUORE experiment under construction at Gran Sasso National Lab in Assergi, Italy. The remainder of the paper will describe the process of creating a working alpha spectrometry system using silicon detectors and NIM and CAMAC electronics. Extensive details of the troubleshooting and calibration period are presented as a way for the reader to better understand the concepts involved in alpha spectroscopy and to not repeat mistakes made in this development process.
P3ht:Pcpdtbt:Pcbm Multi- Polymer Single Layer Solar Cells, Ted Andreas
P3ht:Pcpdtbt:Pcbm Multi- Polymer Single Layer Solar Cells, Ted Andreas
Physics
OPV efficiencies are limited by their narrow absorption; rather than using tandem architecture to overcome this obstacle, our group combined P3HT and PCPDTBT into a single layer BHJ solar cell that achieved 2.0% PCE. This is 33% higher than the pure P3HT control from this group, proving that multi-polymer solar cells have the potential to outperform their single-polymer components.
Estimating The R-Value Of Earth's Atmosphere, David Hafemeister
Estimating The R-Value Of Earth's Atmosphere, David Hafemeister
Physics
No abstract provided.
Accretion Properties Of High- And Low-Excitation Young Radio Galaxies, Donghoon Son, Jong-Hak Woo, Sang Chul Kim, Hai Fu, Nozomu Kawakatu, Vardha N. Bennert, Tohru Nagao, Daeseong Park
Accretion Properties Of High- And Low-Excitation Young Radio Galaxies, Donghoon Son, Jong-Hak Woo, Sang Chul Kim, Hai Fu, Nozomu Kawakatu, Vardha N. Bennert, Tohru Nagao, Daeseong Park
Physics
Young radio galaxies (YRGs) provide an ideal laboratory to explore the connection between the accretion disk and radio jet thanks to their recent jet formation. We investigate the relationship between the emission-line properties, the black hole accretion rate, and the radio properties using a sample of 34 low-redshift (z < 0.4) YRGs. We classify YRGs as high-excitation galaxies (HEGs) and low-excitation galaxies (LEGs) based on the flux ratio of high-ionization to low-ionization emission lines. Using the Hα luminosities as a proxy of accretion rate, we find that HEGs in YRGs have ~1 dex higher Eddington ratios than LEGs in YRGs, suggesting that HEGs have a higher mass accretion rate or higher radiative efficiency than LEGs. In agreement with previous studies, we find that the luminosities of emission lines, in particular Hα, are correlated with radio core luminosity, suggesting that accretion and young radio activities are fundamentally connected.
Performances And Future Plans Of The Lhc Rf, P. Baudrenghien, T. Mastoridis
Performances And Future Plans Of The Lhc Rf, P. Baudrenghien, T. Mastoridis
Physics
The ramp-up of the LHC operation has been exceptionally fast: from the first acceleration of a single bunch at nominal intensity (1.1E11 p) to 3.5 TeV/c on May 2010, to the accumulation of 11 fb-1 integrated luminosity two years later (June 2012). On the RF side this was made possible by a few key design choices and several developments, that allow reliable LHC operation with 0.35 A DC beam at 4 TeV/c (1380 bunches at 50 ns spacing, 1.5E11 p per bunch). This paper reviews the RF design and presents its performance. Plans are also outlined that would allow operation …
Lhc Impedance Model: Experience With High Intensity Operation In The Lhc, B. Salvant, O. Aberle, G. Arduini, R. Assmann, V. Baglin, M.J. Barnes, P. Baudrenghien, A. Bertarelli, C. Bracco, R. Bruce, X. Buffat, F. Carra, G. Cattenoz, F. Caspers, S. Claudet, H. Day, J. Esteban Mueller, M. Garlasché, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, W. Herr, S. Jakobsen, R. Jones, G. Lanza, L. Lari, T. Mastoridis, E. Métral, N. Mounet, A. Nosych, J.L Nougaret, S. Persichelli, T. Pieloni, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, E. Shaposhnikova, L. Tavian, M. Timmins, J. Uythoven, A. Vidal, R. Wasef, D. Wollman, A. Burov, S. White
Lhc Impedance Model: Experience With High Intensity Operation In The Lhc, B. Salvant, O. Aberle, G. Arduini, R. Assmann, V. Baglin, M.J. Barnes, P. Baudrenghien, A. Bertarelli, C. Bracco, R. Bruce, X. Buffat, F. Carra, G. Cattenoz, F. Caspers, S. Claudet, H. Day, J. Esteban Mueller, M. Garlasché, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, W. Herr, S. Jakobsen, R. Jones, G. Lanza, L. Lari, T. Mastoridis, E. Métral, N. Mounet, A. Nosych, J.L Nougaret, S. Persichelli, T. Pieloni, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, E. Shaposhnikova, L. Tavian, M. Timmins, J. Uythoven, A. Vidal, R. Wasef, D. Wollman, A. Burov, S. White
Physics
The CERN Large Hadron Collider (LHC) is now in luminosity production mode and has been pushing its performance in the past months by increasing the proton beam brightness, the collision energy and the machine availability. As a consequence, collective effects have started to become more and more visible and have effectively slowed down the performance increase of the machine. Among these collective effects, the interaction of brighter LHC bunches with the longitudinal and transverse impedance of the machine has been observed to generate beam induced heating, as well as longitudinal and transverse instabilities since 2010. This contribution reviews the current …
Measurements Of The Lhc Longitudinal Resistive Impedance With Beam, J.F. Esteban Muller, T. Argyropoulos, T. Bohl, T. Mastoridis, N. Mounet, G. Papotti, B. Salvant, E. Shaposhnikova, D. Valuch
Measurements Of The Lhc Longitudinal Resistive Impedance With Beam, J.F. Esteban Muller, T. Argyropoulos, T. Bohl, T. Mastoridis, N. Mounet, G. Papotti, B. Salvant, E. Shaposhnikova, D. Valuch
Physics
The resistive part of the longitudinal impedance contributes to the heat deposition on different elements in the LHC ring including the beam screens, where it has to be absorbed by the cryogenic system and can be a practical limitation for the maximum beam intensity. In this paper, we present the first measurements of the LHC longitudinal resistive impedance with beam, done through synchronous phase shift measurements duringMachine Development sessions in 2012. Synchronous phase shift is measured for different bunch intensities and lengths using the high-precision LHC Beam Phase Module and then data are post-processed to further increase the accuracy. The …
Analysis Of Cornell Electron-Positron Storage Ring Test Accelerator's Double Slit Visual Beam Size Monitor, Robert Campbell
Analysis Of Cornell Electron-Positron Storage Ring Test Accelerator's Double Slit Visual Beam Size Monitor, Robert Campbell
Physics
In the past year, a double slit interferometer was installed to measure the horizontal beam size in the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) at Cornell University in Ithaca, NY. To better understand the systematics of this device, a replica of the CesrTA instrument was assembled at California Polytechnic State University San Luis Obispo. From the prototype, it was found that the device will produce a calculated beam size that agrees with measurements as long as it is optimized with the proper double slits for a small range of beam sizes.
The History And Environment Of A Faded Quasar: Hubble Space Telescope Observations Of Hanny’S Voorwerp And Ic 2497, William C. Keel, Chris J. Lintott, Kevin Schawinski, Vardha N. Bennert, Daniel Thomas, Anna Manning, S. Drew Chojnowski, Stuart Lynn
The History And Environment Of A Faded Quasar: Hubble Space Telescope Observations Of Hanny’S Voorwerp And Ic 2497, William C. Keel, Chris J. Lintott, Kevin Schawinski, Vardha N. Bennert, Daniel Thomas, Anna Manning, S. Drew Chojnowski, Stuart Lynn
Physics
We present Hubble Space Telescope imaging and spectroscopy, along with supporting Galaxy Evolution Explorer and ground-based data, for the extended high-ionization cloud known as Hanny's Voorwerp, near the spiral galaxy IC 2497. Wide Field Camera 3 images show complex dust absorption near the nucleus of IC 2497. The galaxy core in these data is, within the errors, coincident with the very long baseline interferometry core component marking the active nucleus. Space Telescope Imaging Spectrograph (STIS) optical spectra show the active galactic nucleus (AGN) to be a type 2 Seyfert galaxy of rather low luminosity. The derived ionization parameter log U …
A Local Baseline Of The Black Hole Mass Scaling Relations For Active Galaxies. Ii. Measuring Stellar Velocity Dispersion In Active Galaxies, Chelsea E. Harris, Vardha N. Bennert, Matthew W. Auger, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan
A Local Baseline Of The Black Hole Mass Scaling Relations For Active Galaxies. Ii. Measuring Stellar Velocity Dispersion In Active Galaxies, Chelsea E. Harris, Vardha N. Bennert, Matthew W. Auger, Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan
Physics
We derive spatially resolved stellar kinematics for a sample of 84 out of 104 observed local (0.02 < z < 0.09) galaxies hosting type-1 active galactic nuclei (AGNs), based on long-slit spectra obtained at the 10 m W. M. Keck-1 Telescope. In addition to providing central stellar velocity dispersions, we measure major axis rotation curves and velocity dispersion profiles using three separate wavelength regions, including the prominent Ca H&K, Mg Ib, and Ca II NIR stellar features. In this paper, we compare kinematic measurements of stellar velocity dispersion obtained for different apertures, wavelength regions, and signal-to-noise ratios, and provide recipes to cross-calibrate the measurements reducing systematic effects to the level of a few percent. We also provide simple recipes based on readily observable quantities such as global colors and Ca H&K equivalent width that will allow observers of high-redshift AGN hosts to increase the probability of obtaining reliable stellar kinematic measurements from unresolved spectra in the region surrounding the Ca H&K lines. In subsequent papers in this series, we will combine this unprecedented spectroscopic data set with surface photometry and black hole mass measurements to study in detail the scaling relations between host galaxy properties and black hole mass.
Nearshore Internal Bores And Turbulent Mixing In Southern Monterey Bay, Ryan K. Walter, C. Brock Woodson, Robert S. Arthur, Oliver B. Fringer, Stephen G. Monismith
Nearshore Internal Bores And Turbulent Mixing In Southern Monterey Bay, Ryan K. Walter, C. Brock Woodson, Robert S. Arthur, Oliver B. Fringer, Stephen G. Monismith
Physics
We observed transient stratification and mixing events associated with nearshore internal bores in southern Monterey Bay using an array of instruments with high spatial and temporal resolution. The arrival of the bores is characterized by surging masses of dense (cold) water that tend to stratify the water column. The bore is followed by a gradual drop in the temperature throughout the water column over several hours (defined here as the bore period) until a sharp warm-front relaxation, followed by high frequency temperature fluctuations, returns the column back to nearly its original state (defined here as the mixing period). Mixing periods …
The Lick Agn Monitoring Project 2011: Dynamical Modeling Of The Broad-Line Region In Mrk 50, Anna Pancoast, Brendon J. Brewer, Tommaso Treu, Aaron J. Barth, Vardha N. Bennert, Gabriela Canalizo, Alexei V. Filippenko, Elinor L. Gates, Jenny E. Greene, Weidong Li, Matthew A. Malkan, David J. Sand, Daniel Stern, Jong-Hak Woo, Roberto J. Assef, Hyun-Jin Bae, Tabitha Buehler, S. Bradley Cenko, Kelsey I. Clubb, Michael C. Cooper, Aleksandar M. Diamond-Stanic, Kyle D. Hiner, Sebastian F. Hönig, Michael D. Joner, Michael T. Kandrashoff, C. David Laney, Mariana S. Lazarova, A.M. Nierenberg, Dawoo Park, Jeffrey M. Silverman, Donghoon Son, Alessandro Sonnenfeld, Shawn J. Thorman, Erik J. Tollerud, Jonelle L. Walsh, Richard Walters
The Lick Agn Monitoring Project 2011: Dynamical Modeling Of The Broad-Line Region In Mrk 50, Anna Pancoast, Brendon J. Brewer, Tommaso Treu, Aaron J. Barth, Vardha N. Bennert, Gabriela Canalizo, Alexei V. Filippenko, Elinor L. Gates, Jenny E. Greene, Weidong Li, Matthew A. Malkan, David J. Sand, Daniel Stern, Jong-Hak Woo, Roberto J. Assef, Hyun-Jin Bae, Tabitha Buehler, S. Bradley Cenko, Kelsey I. Clubb, Michael C. Cooper, Aleksandar M. Diamond-Stanic, Kyle D. Hiner, Sebastian F. Hönig, Michael D. Joner, Michael T. Kandrashoff, C. David Laney, Mariana S. Lazarova, A.M. Nierenberg, Dawoo Park, Jeffrey M. Silverman, Donghoon Son, Alessandro Sonnenfeld, Shawn J. Thorman, Erik J. Tollerud, Jonelle L. Walsh, Richard Walters
Physics
We present dynamical modeling of the broad-line region (BLR) in the Seyfert 1 galaxy Mrk 50 using reverberation mapping data taken as part of the Lick AGN Monitoring Project (LAMP) 2011. We model the reverberation mapping data directly, constraining the geometry and kinematics of the BLR, as well as deriving a black hole mass estimate that does not depend on a normalizing factor or virial coefficient. We find that the geometry of the BLR in Mrk 50 is a nearly face-on thick disk, with a mean radius of 9.6+1.2 –0.9 light days, a width of the BLR of 6.9 …
Cuore Crystal Validation Runs: Results On Radioactive Contamination And Extrapolation To Cuore Background, F. Alessandria, E. Andreotti, R. Ardito, C. Arnaboldi, F. T. Avignone Iii, M. Balata, I. Bandac, T. I. Banks, G. Bari, J. Beeman, F. Bellini, A. Bersani, M. Biassoni, T. Bloxham, C. Brofferio, A. Bryant, C. Bucci, X. Z. Cai, L. Canonica, S. Capelli, L. Carbone, L. Cardani, M. Carrettoni, N. Chott, M. Clemenza, C. Cosmelli, O. Cremonesi, R. J. Creswick, I. Dafinei, A. Dally, A. De Biasi, M. P. Decowski, M. M. Deninno, A. De Waard, S. Di Domizio, L. Ejzak, R. Faccini, D. Q. Fang, H. A. Farach, E. Ferri, F. Ferroni, E. Fiorini, L. Foggetta, S. J. Freedman, G. Frossati, A. Giachero, L. Gironi, A. Giuliani, P. Gorla, C. Gotti, E. Guardincerri, T. D. Gutierrez, E. E. Haller, K. Han, K. M. Heeger, H. Z. Huang, K. Ichimura, R. Kadel, K. Kazkaz, G. Keppel, L. Kogler, Yu. G. Kolomensky, S. Kraft, D. Lenz, Y. L. Li, X. Liu, E. Longo, Y. G. Ma, C. Maiano, G. Maier, C. Martinez, M. Martinez, R. H. Maruyama, N. Moggi, S. Morganti, S. Newman, S. Nisi, C. Nones, E. B. Norman, A. Nucciotti, F. Orio, D. Orlandi, J. L. Ouellet, M. Pallavicini, V. Palmieri, L. Pattavina, M. Pavan, M. Pedretti, G. Pessina, S. Pirro, E. Previtali, V. Rampazzo, F. Rimondi, C. Rosenfeld, C. Rusconi, C. Salvioni, S. Sangiorgio, D. Schaeffer, N. D. Scielzo, M. Sisti, A. R. Smith, F. Stivanello, L. Taffarello, G. Terenziani, W. D. Tian, C. Tomei, S. Trentalange, G. Ventura, M. Vignati, B. S. Wang, H. W. Wang, C. A. Whitten Jr., T. Wise, A. Woodcraft, N. Xu, L. Zanotti, C. Zarra, B. X. Zhu, S. Zucchelli
Cuore Crystal Validation Runs: Results On Radioactive Contamination And Extrapolation To Cuore Background, F. Alessandria, E. Andreotti, R. Ardito, C. Arnaboldi, F. T. Avignone Iii, M. Balata, I. Bandac, T. I. Banks, G. Bari, J. Beeman, F. Bellini, A. Bersani, M. Biassoni, T. Bloxham, C. Brofferio, A. Bryant, C. Bucci, X. Z. Cai, L. Canonica, S. Capelli, L. Carbone, L. Cardani, M. Carrettoni, N. Chott, M. Clemenza, C. Cosmelli, O. Cremonesi, R. J. Creswick, I. Dafinei, A. Dally, A. De Biasi, M. P. Decowski, M. M. Deninno, A. De Waard, S. Di Domizio, L. Ejzak, R. Faccini, D. Q. Fang, H. A. Farach, E. Ferri, F. Ferroni, E. Fiorini, L. Foggetta, S. J. Freedman, G. Frossati, A. Giachero, L. Gironi, A. Giuliani, P. Gorla, C. Gotti, E. Guardincerri, T. D. Gutierrez, E. E. Haller, K. Han, K. M. Heeger, H. Z. Huang, K. Ichimura, R. Kadel, K. Kazkaz, G. Keppel, L. Kogler, Yu. G. Kolomensky, S. Kraft, D. Lenz, Y. L. Li, X. Liu, E. Longo, Y. G. Ma, C. Maiano, G. Maier, C. Martinez, M. Martinez, R. H. Maruyama, N. Moggi, S. Morganti, S. Newman, S. Nisi, C. Nones, E. B. Norman, A. Nucciotti, F. Orio, D. Orlandi, J. L. Ouellet, M. Pallavicini, V. Palmieri, L. Pattavina, M. Pavan, M. Pedretti, G. Pessina, S. Pirro, E. Previtali, V. Rampazzo, F. Rimondi, C. Rosenfeld, C. Rusconi, C. Salvioni, S. Sangiorgio, D. Schaeffer, N. D. Scielzo, M. Sisti, A. R. Smith, F. Stivanello, L. Taffarello, G. Terenziani, W. D. Tian, C. Tomei, S. Trentalange, G. Ventura, M. Vignati, B. S. Wang, H. W. Wang, C. A. Whitten Jr., T. Wise, A. Woodcraft, N. Xu, L. Zanotti, C. Zarra, B. X. Zhu, S. Zucchelli
Physics
The CUORE Crystal Validation Runs (CCVRs) have been carried out since the end of 2008 at the Gran Sasso National Laboratories, in order to test the performance and the radiopurity of the TeO2 crystals produced at SICCAS (Shanghai Institute of Ceramics, Chinese Academy of Sciences) for the CUORE experiment. In this work the results of the first 5 validation runs are presented. Results have been obtained for bulk contaminations and surface contaminations from several nuclides. An extrapolation to the CUORE background has been performed.
The Double Pendulum: Construction And Exploration, Benjamin J. Knudson
The Double Pendulum: Construction And Exploration, Benjamin J. Knudson
Physics
The exploration of a nonlinear mechanical system, the Double Pendulum, a physical pendulum on the end of a physical pendulum, using analytic and experimental approaches. Also included discussion of the design and construction of the Double Pendulum apparatus to work with Vernier LabPro and LoggerPro. The apparatus outputs live data of the angles to a LoggerPro which collects and produces time evolution graphs as well as a corresponding animation lending itself to comparison with theoretical models. Normal mode frequencies are found both analytically and experimentally for the the general (real) double pendulum. Examples of both simple (periodic) and complex (chaotic) …
The Search For Charged Massive Supersymmetric Particles At The Lhc, Aleksey Pavlov
The Search For Charged Massive Supersymmetric Particles At The Lhc, Aleksey Pavlov
Physics
Charged Massive Particles (CHAMPs) are predicted in the Supersymmetry (SUSY) extension of the Standard Model though they have never been ob- served. We look for CHAMPs in the ALICE Detector at the Large Hadron Collider at CERN. While the main purpose of ALICE is to study Quark- Gluon Plasma, we take advantage of the tracking and time of flight capabilities of several sub-detectors in ALICE to look for signs of CHAMPs. These elusive particles are characterized by their slow velocity, high transverse momentum and therefore heavy mass. Our research found a small handful of candidates among a large sample size …
Studying Beam Dynamics At Cesrta, Matthew (Matt) Randazzo
Studying Beam Dynamics At Cesrta, Matthew (Matt) Randazzo
Physics
The Cornell Electron Storage Ring Test Accelerator (CesrTA) is a particle accelerator acting primarily as a laboratory for studying accelerator physics under a variety of conditions. Here, the experimental program on electron cloud effects is one of the highest-priority research and development projects during the International Linear Collider (ILC) Technical Design Phase 1. These electron clouds are of particular concern for the design of future low emittance rings like those in the ILC because of how they can adversely affect the performance of accelerators. The impact of electron clouds on the dynamics of individual bunches along a train known as …
Analysis Of Focal-Plane Measurements For Veritas Telescopes, William Hemmo Schuur
Analysis Of Focal-Plane Measurements For Veritas Telescopes, William Hemmo Schuur
Physics
In this experiment we measured the Point Spread Function (PSF) of the telescope at different image locations using a python GUI and servo motors to automate a screen along the focal axis of the telescope. Our results show that the telescope T4 has a well-defined image distance at each elevation, but this distance shifts as the telescope is lowered. Additionally, off-axis telescope orientations are degraded by aberrations and at low elevation possibly some structural warping of the mirror. The VERITAS Telescopes are located in Southern Arizona at the Fred Lawrence Whipple Observatory.
Gaussian Beam Steering On A Target Plane Via High Speed Orthogonal Mirror-Mounted Galvanometers, Keith Gresiak
Gaussian Beam Steering On A Target Plane Via High Speed Orthogonal Mirror-Mounted Galvanometers, Keith Gresiak
Physics
No abstract provided.
Digital Holography And Applications In Microscopic Interferometry, Cody Jenkins
Digital Holography And Applications In Microscopic Interferometry, Cody Jenkins
Physics
In this project I demonstrate recording holograms using an electronic camera as the photosensitive element and subsequent numerical reconstruction in a digital computer. The technique is employed to show extended depth of field imaging as well as phase contrast imaging via microscopic interferometry.
Multipolymer Interactions In Bulk Heterojunction Photovoltaic Devices, Grant Olson
Multipolymer Interactions In Bulk Heterojunction Photovoltaic Devices, Grant Olson
Physics
Multipolymer photovoltaics, single layer devices made up of multiple photoactive polymers, can create organic photovoltaics (OPVs) with a wider spectral response than single polymer systems without the difficult fabrication of a tandem. Our group has successfully created multipolymer solar devices with 2% power conversion efficiency. We have analyzed the optical and electrical properties of these devices, and found that it may be possible for polymers to assist each other with charge extraction, though combining polymers disrupts single polymer crystallinity.
Approaches To Control Nitrate Pollution In The San Joaquin Watershed, Misgana K. Muleta, Stephen Clayton
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
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
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
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
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
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
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.