Physical Sciences and Mathematics Commons^™

The Runge0lenz Vector (Continued), Carl W. David

Chemistry Education Materials

We continue our discussion of the Runge-Lenz vector in a quantum mechanical context. The traditional form of the Runge-Lenz vector is obtained, and the commutation relations between the Runge-Lenz vector, the Hamiltonian, and the Angular Momentum are obtained using Maple.

Lee O Case's "Elements Of The Phase Rule", Chapter 2, Carl W. David

Chemistry Education Materials

The second chapter of the Case text on the phase rule, this time dealing with two component systems, added to by the author, is presented here.

Complex Electronic States In Double-Layered Ruthenates (Sr1−Xcax)3ru2o7, Zhe Qu, Jin Peng, David Fobes, Leonard Spinu, Zhiqiang Mao

Physics Faculty Publications

The magnetic ground state of (Sr_1−xCa_x)₃Ru₂O₇ (0≤x≤1) is complex, ranging from an itinerant metamagnetic state (0≤x<0.08) to an unusual heavy-mass nearly ferromagnetic (FM) state (0.08<x<0.4), and finally to an antiferromagnetic (AFM) state (0.4≤x≤1). In this report we elucidate the electronic properties for these magnetic states, and show that the electronic and magnetic properties are strongly coupled in this system. The electronic ground state evolves from an AFM quasi-two-dimensional metal for x=1.0 to an Anderson localized state for 0.4≤x<1.0 (the AFM region). When the magnetic state undergoes a transition from the AFM to the nearly FM state, the electronic ground state switches to a weakly localized state induced by magnetic scattering for 0.25≤x<0.4, and then to a magnetic metallic state with the in-plane resistivity ρ_ab∝T^α (α>2) for 0.08<x<0.25. The system eventually transforms into a Fermi-liquid ground state when the magnetic ground state enters the itinerant metamagnetic state for x<0.08. When x approaches the critical composition (x∼0.08), …

Morphology, Magnetic And Dynamic Properties Of Artificial Structures Assembled By Acoustic Vibrations, K B. Paul, L Malkinski

Physics Faculty Publications

Cobalt micromagnetic particles with an average size of ≈ 1.6 μm and varying total mass of the powder were assembled on patterned media with perpendicular magnetization by acoustic vibrations onto designed shapes reflecting the primary material. The replicas were studied with scanning electron microscopy, vibrating sample magnetometry, and ferromagnetic resonance spectroscopy. Their properties were significantly influenced by the shape anisotropy induced through the parent molds. A tendency in the development of the physical characteristics of the replicas was observed as their geometrical parameters changed.

Charge-Carrier Localization Induced By Excess Fe In The Superconductor Fe1+Yte1−Xsex, T J. Liu, X Ke, B Qian, J Hu, D Fobes, E K. Vehstedt, H Pham, J H. Yang, M H. Fang, L Spinu, P Schiffer, Y Liu, Z Q. Mao

Physics Faculty Publications

We have investigated the effect of Fe nonstoichiometry on properties of the Fe_1+y(Te,Se) superconductor system by means of resistivity, Hall coefficient, magnetic susceptibility, and specific-heat measurements. We find that the excess Fe at interstitial sites of the (Te, Se) layers not only suppresses superconductivity but also results in a weakly localized electronic state. We argue that these effects originate from the magnetic coupling between the excess Fe and the adjacent Fe square-planar sheets, which favors a short-range magnetic order.

Dynamic Critical Curve Of A Synthetic Antiferromagnet, Huy Pham, Dorin Cimpoesu, Andrei-Valentin Plamada, Alexandru Stancu, Leonard Spinu

Physics Faculty Publications

We have investigated the effect of Fe nonstoichiometry on properties of the Fe_1+y(Te,Se) superconductor system by means of resistivity, Hall coefficient, magnetic susceptibility, and specific-heat measurements. We find that the excess Fe at interstitial sites of the (Te, Se) layers not only suppresses superconductivity but also results in a weakly localized electronic state. We argue that these effects originate from the magnetic coupling between the excess Fe and the adjacent Fe square-planar sheets, which favors a short-range magnetic order.

Friction On The Microscale, K B. Paul, L Malkinski

Physics Faculty Publications

A new method is presented for measurements of friction of microsized particles on surfaces. Specifically in this work, the particles are alumina with diameters between ≈ 1 and 50 μm and the surfaces are InP, Si, and Cr. Friction is analyzed, its components are determined, and the friction coefficients are estimated from the experimental results. The technique and the specific instrument allow measurements of coefficients of friction for spherical particles with radii as small as 1 μm. For smaller sizes, the instrument needs to be modified by using a more powerful power supply, actuator with extended frequency and …

Structural, Magnetic, And Electronic Transport Properties Of (Sr0.9ca0.1)3ru2o7 Single Crystal, Bin Qian, Zhe Qu, Jin Peng, Tijang Liu, Xiaoshan Wu, L Spinu, Z Q. Mao

Physics Faculty Publications

We have studied the structural, magnetic, and electronic transport properties of (Sr_0.9Ca_0.1)₃Ru₂O₇ using single crystals grown by a floating-zone technique. The structure analysis by Rietveld refinements reveals that the Ca substitution for Sr intensifies the structure distortion; the rotation angle of the RuO₆ octahedron increases. This structure change tunes magnetic and transport properties dramatically. The magnetic ground state switches from an itinerant metamagnetic state for Sr₃Ru₂O₇ to a nearly ferromagnetic state for (Sr_0.9Ca_0.1)₃Ru₂O₇. The Fermi …

Magnetic Entropy Change Of V Substituted Ni–Mn–Ga Heusler Alloy, S G. Min, L Malkinski, Y D. Zhang, S C. Yu, K W. Lee, Y C. Kim

Physics Faculty Publications

The magnetization behaviors have been analyzed for Ni₅₄Mn_21−xV_xGa₂₅ (x = 0,2,4) alloys which were prepared by conventional arc melting method in argon atmosphere. The Curie temperature T_C was found to be 325, 300, and 265 K and the austenitic transition temperature T_A on heating was found to be 315, 217, and 124 K for x = 0, 2, and 4, respectively. The magnetic characteristics were performed with a Quantum Design superconducting quantum interference device magnetometer in the field of up to 20 kOe. A large magnetic entropy change Δ …

Tunable (Δπ, Δπ)-Type Antiferromagnetic Order In Α-Fe(Te,Se) Superconductors, Wei Bao, Y Qiu, Q Huang, M A. Green, P Zajdel, M R. Fitzsimmons, M Zhernenkov, S Chang, M Fang, B Qian, Jinhu Yang, H M. Pham, L Spinu, Z Q. Mao

Physics Faculty Publications

The new α-Fe(Te,Se) superconductors share the common iron building block and ferminology with the LaFeAsO and BaFe₂As₂ families of superconductors. In contrast with the predicted commensurate spin-density-wave order at the nesting wave vector (π, 0), a completely different magnetic order with a composition tunable propagation vector (δπ, δπ) was determined for the parent compound Fe_1+yTe in this powder and single-crystal neutron diffraction study. The new antiferromagnetic order survives as a short-range one even in the highest T_C sample. An alternative to the prevailing nesting Fermi surface mechanism is required to understand the latest family …

2009 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

2009 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

Andrews Hall And Seawater Research Laboratory Dedication, Virginia Institute Of Marine Science; College Of William And Mary

Miscellaneous

Dedication: April 16, 2009. Program of events.

2009 Wachapreague Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

Search For The Lightest Scalar Top Quark In Events With Two Leptons In Pp Collisions At √S = 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Gregory Snow, D0 Collaboration

Kenneth Bloom Publications

We report results of a search for the pair production of the lightest supersymmetric partner of the top quark, t₁, using a data set corresponding to an integrated luminosity of 1 fb⁻¹ collected by the DØ detector at a pp center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. Both scalar top quarks are assumed to decay into a b quark, a charged lepton and a scalar neutrino. The search is performed in the electron plus muon and dielectron final states. The signal topology consists of two isolated leptons, missing transverse energy, and jets. We find …

Measurement Of The Top Quark Mass In Final States With Two Leptons, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration

Kenneth Bloom Publications

We present measurements of the top quark mass (m_t) in tt candidate events with two final state leptons using 1 fb^-1 of data collected by the D0 experiment. Our data sample is selected by requiring two fully identified leptons or by relaxing one lepton requirement to an isolated track if at least one jet is tagged as a b jet. The top quark mass is extracted after reconstructing the event kinematics under the tt hypothesis using two methods. In the first method, we integrate over expected neutrino rapidity distributions, and in the second we calculate a …

Determination Of The Strong Coupling Constant From The Inclusive Jet Cross Section In Pp Collisions At √S= 1.96 Tev, V. M. Abazov, Kenneth A. Bloom, Gregory Snow, D0 Collaboration

Kenneth Bloom Publications

We determine the strong coupling constant α_s and its energy dependence from the p_T dependence of the inclusive jet cross section in pp collisions at √s= 1.96 TeV. The strong coupling constant is determined over the transverse momentum range 50<p_T < 145 GeV. Using perturbative QCD calculations to order O(α_s³) combined with O(α_s⁴) contributions from threshold corrections, we obtain α_s(M_Z) =0.1161_-0.0048^+0.0041. This is the most precise result obtained at a hadron-hadron collider.

Measurement Of The Ww Production Cross Section With Dilepton Final States In Pp Collisions At √S = 1.96 Tev And Limits On Anomalous Trilinear Gauge Couplings, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration

Kenneth Bloom Publications

We provide the most precise measurement of the WW production cross section in pp collisions to date at a center of mass energy of 1.96 TeV, and set limits on the associated trilinear gauge couplings. The WW → ℓνℓ’ν(ℓ,ℓ’ = e, μ) decay channels are analyzed in 1 fb^-1 of data collected by the D0 detector at the Fermilab Tevatron Collider. The measured cross section is σ(pp → WW) = 11.5 ± 2.1 (stat + syst) ± 0.7 (lumi) pb. One- and two-dimensional 95% C.L. limits on trilinear gauge couplings are provided.

Measurement Of Dijet Angular Distributions At √S = 1.96 Tev And Searches For Quark Compositeness And Extra Spatial Dimensions, V. M. Abazov, Kenneth A. Bloom, Gregory R. Snow, D0 Collaboration

Kenneth Bloom Publications

We present the first measurement of dijet angular distributions in pp collisions at √s = 1.96 TeV at the Fermilab Tevatron Collider. The measurement is based on a dataset corresponding to an integrated luminosity of 0:7 fb^-1 collected with the D0 detector. Dijet angular distributions have been measured over a range of dijet masses, from 0.25 TeV to above 1.1 TeV. The data are in good agreement with the predictions of perturbative QCD and are used to constrain new physics models including quark compositeness, large extra dimensions, and TeV^-1 scale extra dimensions. For all models considered, we …

Non-Linearity In Ecosystem Services: Temporal And Spatial Variability In Coastal Protection, Evamaria W. Koch, Edward Barbier, Brian R. Silliman, Denise J. Reed, Gerardo M. E. Perillo, Sally D. Hacker, Elise F. Granek, Jurgenne H. Primavera, Nyawira Muthiga, Stephen Polasky, Benjamin S. Halpern, Christopher J. Kennedy, Carrie V. Kappel, Eric Wolanski

Institute for Sustainable Solutions Publications and Presentations

Natural processes tend to vary over time and space, as well as between species. The ecosystem services these natural processes provide are therefore also highly variable. It is often assumed that ecosystem services are provided linearly (unvaryingly, at a steady rate), but natural processes are characterized by thresholds and limiting functions. In this paper, we describe the variability observed in wave attenuation provided by marshes, mangroves, seagrasses, and coral reefs and therefore also in coastal protection. We calculate the economic consequences of assuming coastal protection to be linear. We suggest that, in order to refine ecosystem-based management practices, it is …

Tr-2009001: Bisc: A Binary Itemset Support Counting Approach Towards Efficient Frequent Itemset Mining, Jinlin Chen, Keli Xiao

Computer Science Technical Reports

No abstract provided.

Tr-2009003: On Proof Realization On Modal Logic, Ren-June Wang

Computer Science Technical Reports

No abstract provided.

Tr-2009008: Randomized Preprocessing Of Homogeneous Linear Systems Of Equations, Victor Y. Pan, Guoliang Qian

Computer Science Technical Reports

No abstract provided.

Tr-2009009: Solving Linear Systems With Randomized Augmentation, Victor Y. Pan, Guoliang Qian

Computer Science Technical Reports

No abstract provided.

Tr-2009010: Randomized Preconditioning Versus Pivoting, Victor Y. Pan, Guoliang Qian, Ai-Long Zheng

Computer Science Technical Reports

No abstract provided.

Tr-2009011: Knowledge-Based Rational Decisions, Sergei Artemov

Computer Science Technical Reports

No abstract provided.

Tr-2009015: Knowledge-Based Rational Decisions And Nash Paths, Sergei Artemov

Computer Science Technical Reports

No abstract provided.

Lattice Operators And Topologies, Eva Cogan

Publications and Research

Working within a complete (not necessarily atomic) Boolean algebra, we use a sublattice to define a topology on that algebra. Our operators generalize complement on a lattice which in turn abstracts the set theoretic operator. Less restricted than those of Banaschewski and Samuel, the operators exhibit some surprising behaviors. We consider properties of such lattices and their interrelations. Many of these properties are abstractions and generalizations of topological spaces. The approach is similar to that of Bachman and Cohen. It is in the spirit of Alexandroff, Frolík, and Nöbeling, although the setting is more general. Proceeding in this manner, we …

The Most Effective Statistical Approach To Correct Environmental Satellite Data, Md Zahidur Rahman, Leonid Roytman

Publications and Research

The proposed paper apply novel statistical approach to correct radiometric data measured by Advanced Very High Resolution Radiometers (AVHRR) onboard the National Oceanic and Atmospheric Administration (NOAA) Polar Orbiting Environmental Satellites (POES). This paper investigates Normalized Difference Vegetation Index (NDVI) stability in the NOAA/NESDIS Global Vegetation Index (GVI) data during 1982-2003. AVHRR weekly data for the five NOAA afternoon satellites for the China dataset is studied, for it includes a wide variety of different ecosystems represented globally. It was found that data for the years 1988, 1992, 1993, 1994, 1995 and 2000 are not stable enough compared to other years …

Four Rivers Basin: Cumberland, Tennessee, Ohio, Mississippi, Daniel I. Carey

Map and Chart--KGS

The Four Rivers Basin includes over 4 ,700 square miles in all or parts of 17 counties. The basin contains more than 10,700 miles of streams.

More than 720 miles of streams assessed in the basin by the Kentucky Division of Water do not support designated uses for warm-water aquatic habitat, fish consumption, primary contact recreation, or secondary contact recreation. Not all streams have been assessed. The percentage of assessed streams not supporting uses was: warm-water aquatic habitat (58 percent); fish consumption (14 percent); primary contact recreation (76 percent); secondary contact recreation (30 percent). Nearly 125 miles of streams have …