Physical Sciences and Mathematics Commons^™

Knots And Random Walks In Vibrated Granular Chains, E. Ben-Naim, Z.A. Daya, P. Vorobieff, R.E. Ecke

Eli Ben-Naim

We study experimentally statistical properties of the opening times of knots in vertically vibrated granular chains. Our measurements are in good qualitative and quantitative agreement with a theoretical model involving three random walks interacting via hard core exclusion in one spatial dimension. In particular, the knot survival probability follows a universal scaling function which is independent of the chain length, with a corresponding diffusive characteristic time scale. Both the large-exit-time and the small-exit-time tails of the distribution are suppressed exponentially, and the corresponding decay coefficients are in excellent agreement with the theoretical values.

Rayleigh And Raman Scattering, David W. Ball

Chemistry Faculty Publications

Details the molecular aspect of Raman spectroscopy. Overview on the molecular absorption process; Information on Rayleigh scattering; Effects of the Raman scattering.

Economics As A Life Science: Review Of You Can't Eat Gnp: Economics As If Ecology Mattered By Eric A. Davidson And The Nature Of Economies By Jane Jacobs, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Two Book Reviews: You Can?t Eat GNP: Economics As If Ecology Mattered by Eric A. Davidson and The Nature of Economies by Jane Jacobs

Simulations Of Ice And Liquid Water Over A Range Of Temperatures Using The Fluctuating Charge Model, Steven W. Rick

Chemistry Faculty Publications

The temperature dependence of the thermodynamic and dynamical properties of liquid water using the polarizable fluctuating charge (FQ) model is presented. The properties of ice Ih, both for a perfect lattice with no thermal disorder and at a temperature of 273 K, are also presented. In contrast to nonpolarizable models, the FQ model has a density maximum of water near 277 K. For ice, the model has a dipole moment of the perfect lattice of 3.05 Debye, in good agreement with a recent induction model calculation. The simulations at 273 K and the correct density find that thermal motion decreases …

Tilted Bilayer Membranes As Simple Transmission Quarter-Wave Retardation Plates, R. M.A. Azzam, Fadi A. Mahmoud

Electrical Engineering Faculty Publications

A tilted bilayer membrane, which consists of two thin films of transparent optically isotropic materials of different refractive indices, can function as a transmission quarter-wave retarder (QWR) at a high angle of incidence. A specific design using a cryolite-Si membrane in the infrared is presented, and its tolerances to small shifts of wavelength, incidence angle, and film thickness errors are discussed. Some designs provide a dual QWR in transmission and reflection. Such devices provide simple linear-to-circular (and circular-to-linear) polarization transformers. Bilayer eighth-wave retarders without diattenuation are also introduced.

Charge Exchange Contribution To The Decay Of The Ring Current, Measured By Energetic Neutral Atoms (Enas), A. M. Jorgensen, M. G. Henderson, E. C. Roelof, G. D. Reeves, Harlan E. Spence

Physics & Astronomy

In this paper we calculate the contribution of charge exchange to the decay of the ring current. Past works have suggested that charge exchange of ring current protons is primarily responsible for the decay of the ring current during the late recovery phase, but there is still much debate about the fast decay of the early recovery phase. We use energetic neutral atom (ENA) measurements from Polar to calculate the total ENA energy escape. To get the total ENA escape we apply a forward modeling technique, and to estimate the total ring current energy escape we use the Dessler-Parker-Sckopke relationship. …

Boundary Filters For Size-Limited Paraunitary Filter Banks With Maximum Coding Gain And Ideal Dc Behavior, Alfred Mertins

Faculty of Informatics - Papers (Archive)

This paper presents boundary optimization techniques for the processing of arbitrary-length signals with paraunitary multirate filter banks. The boundary filters are designed to maximize the coding gain while providing an ideal DC behavior where all filters except the low-pass filters have zero mean. Moreover, solutions are presented that have similar frequency responses as the original subband filters. The proposed methods give direct solutions to the problem of finding the optimal boundary filters with maximum coding gain and do not require numerical optimization. Thus, they are even applicable to systems with a large number of subbands and/or very long filter impulse …

Equitability In Retroactive Data Confiscation Versus Proactive Key Escrow, Y. Desmedt, M. Burmester, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

The British Regulations of Investigatory Powers (RIP) Act 2000 is one of the first modern bills for mandatory disclosure of protected data in a democratic country. In this paper we compare this bill from a technical point of view with the US key escrow proposal (EES) and its variants and then, more generally we compare the merits of key confiscation vs key escrow. A major problem with key escrow is that once a private key is recovered it can be used to decipher ciphertexts which were sent well before a war-rant was issued (or after its expiration). Several alternative key …

Parallel 3d Reconstruction Of Assymmetric Virus Structure From Electron From Electron Micrographs: Algorithms And Experiments, Robert E. Lynch, Dan C. Marinescu, Yongchang Ji, Hong Lin

Department of Computer Science Technical Reports

No abstract provided.

Configuration Space Computations For Polyhedra With Planar Motions, Elisha Sacks

Department of Computer Science Technical Reports

No abstract provided.

A Framework For Supporting The Class Of Space Partitioning, Walid G. Aref, Ihab F. Ilyas

Department of Computer Science Technical Reports

No abstract provided.

Adaptive Proportional-Delay Differentiated Services: Characterization And Performance Evaluation, Matthew K. H. Leung, John C. S. Lui, David K.Y. Yau

Department of Computer Science Technical Reports

No abstract provided.

Effects Of External Electric Field On The Interfacial Properties Of Weakly Dipolar Fluid, V.B. Warshavsky, T.V. Bykov, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

In the framework of modified mean-field density-functional theory, effects of a uniform electric field on the interfacial properties of a model dipolar fluid [Teixeira and Telo da Gama, J. Phys.: Condens. Matter 3, 111 (1991)] are studied. Both density and orientational order-parameter profiles of the planar vapor-liquid interface are obtained as a function of the field strength. For the dipolar fluids with reduced dipole moment μ₀^*0^*E*/T*!1) can shift the surface tension by few percent. We also find that the electric field actually reduces the thermodynamical surface tension but enhances the mechanical surface …

Discrepancy Convergence For The Drunkard's Walk On The Sphere, Francis E. Su

All HMC Faculty Publications and Research

We analyze the drunkard's walk on the unit sphere with step size θ and show that the walk converges in order C/sin²(θ) steps in the discrepancy metric (C a constant). This is an application of techniques we develop for bounding the discrepancy of random walks on Gelfand pairs generated by bi-invariant measures. In such cases, Fourier analysis on the acting group admits tractable computations involving spherical functions. We advocate the use of discrepancy as a metric on probabilities for state spaces with isometric group actions.

Particle Size Determination: An Undergraduate Lab In Mie Scattering, I. Weiner '01, M. Rust '01, Thomas D. Donnelly

All HMC Faculty Publications and Research

A technique for determining the size of microscopic spherical particles using light scattering is presented as an undergraduate physics lab. Scatterer size is determined from angular scattering distribution measurements of laser light scattered from a dilute suspension of latex spheres with diameters of 4.99±0.05 and 6.038±0.045 μm. Previous experiments of this type used approximate theoretical corrections and required the construction of specialized sample cells to minimize complicating effects. As a significant improvement to these, we generate angular scattering distributions from Mie theory and, using an accurate numerical procedure, correct these distributions for Snell’s law and foreshortening effects. Scatterer size …

Polarization Retention In Srbi2Ta2O9 Thin Films Investigated At Nanoscale, Alexei Gruverman, M. Tanaka

Alexei Gruverman Publications

The nanoscale mechanism of retention behavior in SrBi₂Ta₂O₉ (SBT) thin films has been investigated by means of piezoresponse scanning force microscopy. It has been found that SBT films with Pt electrodes (SBT/Pt) exhibit a strong dependence of retention characteristics upon domain polarity: positive domains with the polarization vector pointing to the bottom electrode exhibit excellent stability in sharp contrast to the negative domains which show poor retention. The backswitching of the negative domains proceeds via sidewise motion of the domain walls and shows a log-time dependence. The strong effect of the poling voltage parameters (duration …

Fully Differential Cusp Electron Production Cross Sections For 75-Kev H₂⁺ + He Collisions, L. An, Kh Khayvat, Michael Schulz

Physics Faculty Research & Creative Works

A kinematically complete experiment on single ionization for 75-keV H₂⁺ + H e collisions was performed by measuring the fully momentum analyzed projectiles and recoil ions in coincidence. The electron momentum was deduced from momentum conservation. Clear signatures of the postcollision interaction between the outgoing projectiles and the electrons were observed in the momentum spectra of all collision products simultaneously.

Dirac Theory Of Ring-Shaped Electron Distributions In Atoms, P Krekora, R E. Wagner, Q Su, Rainer Grobe

Faculty publications – Physics

The time-dependent Dirac equation is solved numerically on a space-time grid for an atom in a strong static magnetic field and a laser field. The resonantly induced relativistic motion of the atomic electron leads to a ringlike spatial probability density similar to the features that have been recently predicted [Wagner, Su, and Grobe, Phys. Rev. Lett. 84, 3282 (2000)] based on a phase-space method. We further demonstrate that spin-orbit coupling for a fast-moving electron in such an atom becomes significant and the time dependence of the spin can dephase even if initially aligned parallel to the direction of the static …

Radar Studies Of Mid-Latitude Ionospheric Plasma Drifts, L. Scherliess, Bela G. Fejer, J. Holt, L. Goncharenko, C. Armory-Mazaudier, M. J. Buonsanto

Bela G. Fejer

We use incoherent scatter radar measurements from Millstone Hill and Saint Santin to study the midlatitude F region electrodynamic plasma drifts during geomagnetically quiet and active periods. We present initially a local time, season, and solar flux dependent analytical model of the quiet time zonal and meridional E × B drifts over these stations. We discuss, for the first time, the Saint Santin drift patterns during solar maximum. We have used these quiet time models to extract the geomagnetic perturbation drifts which were modeled as a function of the time history of the auroral electrojet indices. Our results illustrate the …

Ionizing Radiation Exposure Of Workers In Medicine And Industry Assessment Of The Present Radiation Safety Program In Dubai And Propositions To Its Upgrading, Najib Abdullah Al Haj Fadhlani

Theses

Many of the latest practices in the fields of medicine and industry in the United Arab Emirates involve the use of radioactive ionizing sources and equipment of ionizing radiation.

The radioactive sources are the materials, which produce nuclear radiation such as alpha, beta, gamma and neutron. These sources have important practical usefulness in the field of industry such as evaluating oil wells and tracing out corrosion of pipes and Concrete as well as in medicine for medical diagnosis and treating cancer. On the other hand, radiation has negative effects as in the case of radiation pollution or worker exposure to …

Synthons And Design In Metal Phosphates And Oxalates With Open Architectures, Chintamani Nagesa Ramachandra Rao, Srinivasan R. Natarajan, Amitava Choudhury, Sharma Neeraj, Ramamurthy Vaidhyanathana

Chemistry Faculty Research & Creative Works

We briefly describe the structures of open-framework metal phosphates with different dimensionalities, such as the one-dimensional linear-chain and ladder structures, two-dimensional layer structures and three-dimensional structures with channels. We demonstrate the role of the zero-dimensional four-membered ring monomer and of the one-dimensional ladder structure as the starting building units or synthons involved in the formation of the complex architectures. Thus, we show how the one-dimensional ladder structure transforms to two- and three-dimensional structures under mild conditions. The two-dimensional layer structures also transform to three-dimensional structures, while the zero-dimensional monomer transforms to layered and three-dimensional structures under ordinary reaction conditions. These …

Measurement Of The Top Quark Mass With The Collider Detector At Fermilab, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

This report describes a measurement of the top quark mass in pp̅ collisions at a center of mass energy of 1.8 TeV. The data sample was collected with the CDF detector during the 1992–1995 collider run at the Fermilab Tevatron, and corresponds to an integrated luminosity of 106 pb^-1. Candidate tt̅ events in the ‘‘lepton+jets’’ decay channel provide our most precise measurement of the top quark mass. For each event a top quark mass is determined by using energy and momentum constraints on the production of the tt̅ pair and its subsequent decay. A likelihood fit to the …

Two-Dimensional Black Holes As Open Strings: A New Realization Of The Ads/Cft Correspondence, Mariano Cadoni, Marco Cavaglia

Physics Faculty Research & Creative Works

We show that weak-coupled two-dimensional dilation gravity on anti-de Sitter space can be described by the dynamics of an open string. Neumann and Dirichlet boundary conditions for the string lead two different realizations of the anti-de Sitter/Conformal Field Theory correspondence. In particular, in the Dirichlet case the thermodynamical entropy of two-dimensional black holes can be exactly reproduced by counting the string states.

Surface Water Quality - 2000 Hillsborough County, Florida Raw Data Summary, Tom Cardinale

Reports

The Environmental Protection Commission of Hillsborough County (EPC) is charged with the responsibility of monitoring the quality of surface water in the county. The data and information collected enables staff to determine pollution status and trends throughout Tampa Bay and our tributaries. The data is also widely distributed to other government agencies, academia, the local scientific community and the general public. EPC's routine monthly surface water monitoring began in January of 1972, with the Tampa Bay estuary and was expanded to major rivers and streams in 1973. This report is a tabulation of the raw data produced on surface water …

A Spectroscopic And Photometric Study Of Short-Timescale Variability In Ngc 5548, M. Dietrich, C. F. Bender, D. J. Bergmann, T. E. Bills, N. G. Bochkarev, A. Burenkov, C. Martin Gaskell, D. D. Gutzmer, R. Grove, M. E. Hiller, J. P. Huchra, Elizabeth S. Klimek, C. Lund, Nelly I. Merkulova, S. Pebley, Matt Poulsen, V. I. Pronik, S. G. Sergeev, E. A. Sergeeva, A. I. Shapovalova, V. V. Vlasyuk, Belinda J. Wilkes

Department of Physics and Astronomy: Faculty Publications

Results of a ground-based optical monitoring campaign on NGC 5548 in June 1998 are presented. The broad-band fluxes (U, B, V), and the spectrophotometric optical continuum flux F_λ (5100 Å) monotonically decreased in flux while the broad-band R and I fluxes and the integrated emission-line fluxes of Hα and Hβ remained constant to within 5% . On June 22, a short continuum flare was detected in the broad band fluxes. It had an amplitude of about ~18% and it lasted only ≈90 min. The broad band fluxes and the optical continuum F_λ (5100 Å) appear to …

Cryptanalysis Of A Digital Signature Scheme On Id-Based Key-Sharing Infrastructures, Hongjun Wu, Feng Bao, Robert H. Deng

Research Collection School Of Computing and Information Systems

At ISW’99, Nishioka, Hanaoka and Imai proposed a digital signature scheme on ID-based key-sharing infrastructures. That signature scheme is claimed to be secure if the discrete logarithm problem is hard to solve. Two schemes (the ID-type and the random-type schemes) based on the linear scheme for the Key Predistribution Systems (KPS) and the discrete logarithm problem (DLP) were given. In this paper we show that those two schemes fail to meet the nonrepudiation requirement: with negligible amount of computation, a signature could be forged. For the ID-type signature scheme, any verifier could forge a signature to raise repudiation between that …

City Of Poquoson Shoreline Situation Report, Marcia Berman, Harry Berquist, Sharon Dewing, J. B. Glover, Carl Hershner, Tamia Rudnicky, Daniel E. Schatt, Kevin Skunda

Reports

No abstract provided.

Demonstration Of Best Management Practices For The Protection And Improvement Of The Soil And Water Resources In The Arkansas Delta, M. A. Henslee, W. H. Baker, S. D. Carroll, J. L. Farris, S. D. Davis, C. D. Milam, J. L. Pierce

Technical Reports

This report is the compilation of a multi~year project that was directed at identifying the impact and possible mitigation solutions of non-point pollution from row crop agriculture in a watershed in the Arkansas Delta. The first part of the project involved an inventory of the condition of the major streams that make up the study watershed. The remainder of the project was focused at demonstrating and reporting best management nutrient and sediment runoff control practices (BMP) that could be implemented. The final assessment of the demonstration work is a GIS analysis that provides an overview of the effectiveness of these …

Polarization Effects In Quantum Coherences Probed By Two-Color, Resonant Four-Wave Mixing In The Time Domain, Elizabeth Mccormack, E. Sarajlic

Physics Faculty Research and Scholarship

We present a combined theoretical and experimental study of the effects of laser polarization on optical coherences produced in two-color, resonant four-wave mixing (TC-RFWM). A time-dependent model incorporating diagrammatic perturbation theory and spherical tensor formalism is used to interpret observations of quantum beats due to molecular hyperfine structure in time-resolved TC-RFWM in nitric oxide. Good agreement is found between the model and the observed time-resolved signals for two distinct excitation schemes and a variety of polarization configurations including both polarization and population gratings. Measured hyperfine energy intervals are reported for the X(2)Pi (1/2) , v = 0 ground state and …

Refined Kinematics Of The Eastern California Shear Zone From Gps Observations, 1993-1998, M. Meghan Miller, Daniel J. Johnson, Timothy H. Dixon, Roy K. Dokka

School of Geosciences Faculty and Staff Publications

Global Positioning System (GPS) results from networks spanning the Eastern California shear zone and adjacent Sierra Nevada block, occupied annually between 1993 and 1998, constrain plate margin kinematics. We use an elastic block model to relate GPS station velocities to long-term fault slip rate estimates. The model accounts for elastic strain accumulation on the San Andreas fault, as well as faults of the Eastern California shear zone. South of the Garlock fault, 14 mm/yr of dextral shear is distributed across the Eastern California shear zone. Some of this slip penetrates eastward into the Basin and Range, and a collective budget …