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Aharmim B, Ahmed SN, Amsbaugh JF, Anthony AE, Banar J, Barros N, Beier EW, Bellerive A, Beltran B, Bergevin M, Biller SD, Boudjemline K, Boulay MG, Bowles TJ, Browne MC, Bullard TV, Burritt TH, Cai B, Chan YD, Chauhan D, Chen M, Cleveland BT, Cox-Mobrand GA, Currat CA, Dai X, Deng H, Detwiler J, DiMarco M, Doe PJ, Doucas G, Drouin PL, Duba CA, Duncan FA, Dunford M, Earle ED, Elliott SR, Evans HC, Ewan GT, Farine J, Fergani H, Fleurot F, Ford RJ, Formaggio JA, Fowler MM, Gagnon N, Germani JV, Goldschmidt A, Goon JTM, Graham K, Guillian E, Habib S, Hahn RL, Hallin AL, Hallman ED, Hamian AA, Harper GC, Harvey PJ, Hazama R, Heeger KM, Heintzelman WJ, Heise J, Helmer RL, Henning R, Hime A, Howard C, Howe MA, Huang M, Jagam P, Jamieson B, Jelley NA, Keeter KJ, Klein JR, Kormos LL, Kos M, Krüger A, Kraus C, Krauss CB, Kutter T, Kyba CCM, Lange R, Law J, Lawson IT, Lesko KT, Leslie JR, Loach JC, MacLellan R, Majerus S, Mak HB, Maneira J, Martin R, McBryde K, McCauley N, McDonald AB, McGee S, Mifflin C, Miller GG, Miller ML, Monreal B, Monroe J, Morissette B, Myers A, Nickel BG, Noble AJ, Oblath NS, O'Keeffe HM, Ollerhead RW, Gann GDO, Oser SM, Ott RA, Peeters SJM, Poon AWP, Prior G, Reitzner SD, Rielage K, Robertson BC, Robertson RGH, Rollin E, Schwendener MH, Secrest JA, Seibert SR, Simard O, Simpson JJ, Sinclair L, Skensved P, Smith MWE, Steiger TD, Stonehill LC, Tesić G, Thornewell PM, Tolich N, Tsui T, Tunnell CD, Van Wechel T, Van Berg R, VanDevender BA, Virtue CJ, Walker TJ, Wall BL, Waller D, Tseung HWC, Wendland J, West N, Wilhelmy JB, Wilkerson JF, Wilson JR, Wouters JM, Wright A, Yeh M, Zhang F, Zuber K. Independent measurement of the total active 8B solar neutrino flux using an array of 3He proportional counters at the Sudbury Neutrino Observatory. Phys Rev Lett 2008; 101:111301. [PMID: 18851271 DOI: 10.1103/physrevlett.101.111301] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Indexed: 05/26/2023]
Abstract
The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (nu_x) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54_-0.31;+0.33(stat)-0.34+0.36(syst)x10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Deltam2=7.59_-0.21;+0.19x10(-5) eV2 and theta=34.4_-1.2;+1.3 degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results.
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Affiliation(s)
- B Aharmim
- Department of Physics and Astronomy, Laurentian University, Sudbury, ON P3E 2C6, Canada
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Lee-Dadswell GR, Nickel BG, Gray CG. Thermal conductivity and bulk viscosity in quartic oscillator chains. Phys Rev E Stat Nonlin Soft Matter Phys 2005; 72:031202. [PMID: 16241419 DOI: 10.1103/physreve.72.031202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2005] [Indexed: 05/05/2023]
Abstract
We propose a relation which predicts the low-frequency thermal conductivity of a one-dimensional (1D) system from the thermal conductivity and bulk viscosity at higher frequency. Our theory is based on the assumption that "ballistic" transport by sound waves dominates the heat transport. For a system with equal heat capacities (c(p) = c(v)) this relation is particularly simple. We test the prediction by simulating a chain of particles with quartic interparticle potentials under zero pressure conditions. As the frequency omega --> 0 the theory predicts that the energy current power spectrum diverges as omega(-1/2), not seen in previous simulations. Because we simulate very long chains to long times we do observe the crossover into this regime. The bulk viscosity of a 1D chain has been determined via simulation. It is found to be finite for our system, in contrast to the thermal conductivity which is infinite.
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Affiliation(s)
- G R Lee-Dadswell
- Department of Physics, University of Guelph, Guelph, Ontario, Canada, N1G 2W1.
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Roth CB, Deh B, Nickel BG, Dutcher JR. Evidence of convective constraint release during hole growth in freely standing polystyrene films at low temperatures. Phys Rev E Stat Nonlin Soft Matter Phys 2005; 72:021802. [PMID: 16196592 DOI: 10.1103/physreve.72.021802] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Revised: 04/25/2005] [Indexed: 05/04/2023]
Abstract
Hole growth measurements were performed using optical microscopy on freely standing polystyrene films at temperatures that were slightly larger than the bulk value of the glass transition temperature T(bulk)g. For the measured range of temperatures, we have observed a transition from linear growth of the hole radius R during the early stages to exponential growth of R at later times. We have characterized this transition as a function of molecular weight 120 x 10(3) < Mw <2240 x 10(3) , film thickness 61 nm<h<125 nm , and temperature 101 degrees C<T<117 degrees C . The viscosity at the edge of the hole inferred from the long time exponential growth regime exhibits shear thinning due to the large shear strain rates present at the edge of the hole. The R (t) data for all times can be fit very well using an expression that describes exponential hole growth with a time-dependent viscosity that allows for an initial, transient response due to the decay of elastic entanglements. The time scale for the decay of the transient behavior is interpreted in terms of the decay of entanglements by the convective constraint release mechanism of the tube theory of entangled polymer dynamics.
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Affiliation(s)
- C B Roth
- Department of Physics and the Guelph-Waterloo Physics Institute, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Ahmed SN, Anthony AE, Beier EW, Bellerive A, Biller SD, Boger J, Boulay MG, Bowler MG, Bowles TJ, Brice SJ, Bullard TV, Chan YD, Chen M, Chen X, Cleveland BT, Cox GA, Dai X, Dalnoki-Veress F, Doe PJ, Dosanjh RS, Doucas G, Dragowsky MR, Duba CA, Duncan FA, Dunford M, Dunmore JA, Earle ED, Elliott SR, Evans HC, Ewan GT, Farine J, Fergani H, Fleurot F, Formaggio JA, Fowler MM, Frame K, Fulsom BG, Gagnon N, Graham K, Grant DR, Hahn RL, Hall JC, Hallin AL, Hallman ED, Hamer AS, Handler WB, Hargrove CK, Harvey PJ, Hazama R, Heeger KM, Heintzelman WJ, Heise J, Helmer RL, Hemingway RJ, Hime A, Howe MA, Jagam P, Jelley NA, Klein JR, Kos MS, Krumins AV, Kutter T, Kyba CCM, Labranche H, Lange R, Law J, Lawson IT, Lesko KT, Leslie JR, Levine I, Luoma S, MacLellan R, Majerus S, Mak HB, Maneira J, Marino AD, McCauley N, McDonald AB, McGee S, McGregor G, Mifflin C, Miknaitis KKS, Miller GG, Moffat BA, Nally CW, Nickel BG, Noble AJ, Norman EB, Oblath NS, Okada CE, Ollerhead RW, Orrell JL, Oser SM, Ouellet C, Peeters SJM, Poon AWP, Robertson BC, Robertson RGH, Rollin E, Rosendahl SSE, Rusu VL, Schwendener MH, Simard O, Simpson JJ, Sims CJ, Sinclair D, Skensved P, Smith MWE, Starinsky N, Stokstad RG, Stonehill LC, Tafirout R, Takeuchi Y, Tesić G, Thomson M, Thorman M, Van Berg R, Van de Water RG, Virtue CJ, Wall BL, Waller D, Waltham CE, Tseung HWC, Wark DL, West N, Wilhelmy JB, Wilkerson JF, Wilson JR, Wouters JM, Yeh M, Zuber K. Measurement of the total active 8B solar neutrino flux at the Sudbury Neutrino Observatory with enhanced neutral current sensitivity. Phys Rev Lett 2004; 92:181301. [PMID: 15169480 DOI: 10.1103/physrevlett.92.181301] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2003] [Indexed: 05/24/2023]
Abstract
The Sudbury Neutrino Observatory has precisely determined the total active (nu(x)) 8B solar neutrino flux without assumptions about the energy dependence of the nu(e) survival probability. The measurements were made with dissolved NaCl in heavy water to enhance the sensitivity and signature for neutral-current interactions. The flux is found to be 5.21 +/- 0.27(stat)+/-0.38(syst) x 10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of these and other solar and reactor neutrino results yields Deltam(2)=7.1(+1.2)(-0.6) x 10(-5) eV(2) and theta=32.5(+2.4)(-2.3) degrees. Maximal mixing is rejected at the equivalent of 5.4 standard deviations.
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Affiliation(s)
- S N Ahmed
- Department of Physics, Queen's University, Kingston, Ontario K7L 3N6 Canada
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Ahmed SN, Anthony AE, Beier EW, Bellerive A, Biller SD, Boger J, Boulay MG, Bowler MG, Bowles TJ, Brice SJ, Bullard TV, Chan YD, Chen M, Chen X, Cleveland BT, Cox GA, Dai X, Dalnoki-Veress F, Doe PJ, Dosanjh RS, Doucas G, Dragowsky MR, Duba CA, Duncan FA, Dunford M, Dunmore JA, Earle ED, Elliott SR, Evans HC, Ewan GT, Farine J, Fergani H, Fleurot F, Formaggio JA, Fowler MM, Frame K, Frati W, Fulsom BG, Gagnon N, Graham K, Grant DR, Hahn RL, Hall JC, Hallin AL, Hallman ED, Hamer AS, Handler WB, Hargrove CK, Harvey PJ, Hazama R, Heeger KM, Heintzelman WJ, Heise J, Helmer RL, Hemingway RJ, Hime A, Howe MA, Jagam P, Jelley NA, Klein JR, Kos MS, Krumins AV, Kutter T, Kyba CCM, Labranche H, Lange R, Law J, Lawson IT, Lesko KT, Leslie JR, Levine I, Luoma S, MacLellan R, Majerus S, Mak HB, Maneira J, Marino AD, McCauley N, McDonald AB, McGee S, McGregor G, Mifflin C, Miknaitis KKS, Miller GG, Moffat BA, Nally CW, Neubauer MS, Nickel BG, Noble AJ, Norman EB, Oblath NS, Okada CE, Ollerhead RW, Orrell JL, Oser SM, Ouellet C, Peeters SJM, Poon AWP, Robertson BC, Robertson RGH, Rollin E, Rosendahl SSE, Rusu VL, Schwendener MH, Simard O, Simpson JJ, Sims CJ, Sinclair D, Skensved P, Smith MWE, Starinsky N, Stokstad RG, Stonehill LC, Tafirout R, Takeuchi Y, Tesić G, Thomson M, Thorman M, Van Berg R, Van de Water RG, Virtue CJ, Wall BL, Waller D, Waltham CE, Tseung HWC, Wark DL, West N, Wilhelmy JB, Wilkerson JF, Wilson JR, Wittich P, Wouters JM, Yeh M, Zuber K. Constraints on nucleon decay via invisible modes from the Sudbury Neutrino Observatory. Phys Rev Lett 2004; 92:102004. [PMID: 15089201 DOI: 10.1103/physrevlett.92.102004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2003] [Indexed: 05/24/2023]
Abstract
Data from the Sudbury Neutrino Observatory have been used to constrain the lifetime for nucleon decay to "invisible" modes, such as n-->3nu. The analysis was based on a search for gamma rays from the deexcitation of the residual nucleus that would result from the disappearance of either a proton or neutron from 16O. A limit of tau(inv)>2 x 10(29) yr is obtained at 90% confidence for either neutron- or proton-decay modes. This is about an order of magnitude more stringent than previous constraints on invisible proton-decay modes and 400 times more stringent than similar neutron modes.
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Affiliation(s)
- S N Ahmed
- Department of Physics, Queen's University, Kingston, Ontario, Canada K7L 3N6
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Orrick WP, Nickel BG, Guttmann AJ, Perk JH. Critical behavior of the two-dimensional Ising susceptibility. Phys Rev Lett 2001; 86:4120-4123. [PMID: 11328110 DOI: 10.1103/physrevlett.86.4120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2000] [Indexed: 05/23/2023]
Abstract
We report computations of the short- and long-distance (scaling) contributions to the square-lattice Ising susceptibility. Both computations rely on summation of correlation functions, obtained using nonlinear partial difference equations. In terms of a temperature variable tau, linear in T/Tc-1, the short-distance terms have the form tau(p)(ln/tau/)q with p> or =q2. A high- and low-temperature series of N = 323 terms, generated using an algorithm of complexity O(N6), are analyzed to obtain the scaling part, which when divided by the leading /tau/(-7/4) singularity contains only integer powers of tau. Contributions of distinct irrelevant variables are identified and quantified at leading orders /tau/(9/4) and /tau/(17/4).
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Affiliation(s)
- W P Orrick
- Department of Mathematics & Statistics, The University of Melbourne, Parkville, Victoria 3010, Australia.
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Harris AB, Leath PL, Nickel BG, Elliott RJ. Excitations in the dilute Heisenberg ferromagnet using the coherent potential approximation. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/7/9/010] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Jaffer KM, Opps SB, Sullivan DE, Nickel BG, Mederos L. The nematic-isotropic phase transition in semiflexible fused hard-sphere chain fluids. J Chem Phys 2001. [DOI: 10.1063/1.1340606] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Membrane properties that vary as a result of isotropic and transmembrane osmolality variations (osmotic stress) are of considerable relevance to mechanisms such as osmoregulation, in which a biological system "senses" and responds to changes in the osmotic environment. In this paper the light-scattering behavior of a model system consisting of large unilamellar vesicles of dioleoyl phosphatidyl glycerol (DOPG) is examined as a function of their osmotic environment. Osmotic downshifts lead to marked reductions in the scattered intensity, whereas osmotic upshifts lead to strong intensity increases. It is shown that these changes in the scattering intensity involve changes in the refractive index of the membrane bilayer that result from an alteration in the extent of hydration and/or the phospholipid packing density. By considering the energetics of osmotically stressed vesicles, and from explicit analysis of the Rayleigh-Gans-Debye scattering factors for spherical and ellipsoidal shells, we quantitatively demonstrate that although changes in vesicle volume and shape can arise in response to the imposition of osmotic stress, these factors alone cannot account for the observed changes in scattered intensity.
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Affiliation(s)
- G White
- Department of Physics, University of Guelph, Ontario, Canada
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Abstract
Vesicle polydispersity and leakage of solutes from the vesicle lumen influence the measurement and analysis of osmotically induced vesicle swelling and lysis, but their effects have not been considered in previous studies of these processes. In this study, a model is developed which expressly includes polydispersity and leakage effects. The companion paper demonstrated the preparation and characterization of large unilamellar lipid vesicles. A dye release technique was employed to indicate the leakage of solutes from the vesicles during osmotic swelling. Changes in vesicle size were monitored by dynamic light scattering (DLS). In explaining the results, the model identifies three stages. The first phase involves differential increases in membrane tension with strain increasing in larger vesicles before smaller ones. In the second phase, the yield point for lysis (leakage) is reached sequentially from large sizes to small sizes. In the final phase, the lumen contents and the external medium partially equilibrate under conditions of constant membrane tension. When fit to the data, the model yields information on polydispersity-corrected values for membrane area compressibility, Young's modulus, and yield point for lysis.
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Affiliation(s)
- F R Hallett
- Guelph-Waterloo Program for Graduate Work in Physics, University of Guelph, Ontario, Canada
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Dutcher JR, Lee S, Hillebrands B, McLaughlin GJ, Nickel BG, Stegeman GI. Surface-grating-induced zone folding and hybridization of surface acoustic modes. Phys Rev Lett 1992; 68:2464-2467. [PMID: 10045404 DOI: 10.1103/physrevlett.68.2464] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Bagnuls C, Bervillier C, Meiron DI, Nickel BG. Nonasymptotic critical behavior from field theory at d=3. II. The ordered-phase case. Phys Rev B Condens Matter 1987; 35:3585-3607. [PMID: 9941864 DOI: 10.1103/physrevb.35.3585] [Citation(s) in RCA: 144] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Abstract
The lateral separation of virus rod particles of tobacco mosaic virus has been studied as a function of externally applied osmotic pressure using an osmotic stress technique. The results have been used to test the assumption that lattice equilibrium in such gels results from a balance between repulsive (electrostatic) and attractive (van der Waals and osmotic) forces. Results have been obtained at different ionic strengths (0.001 to 1.0 M) and pH's (5.0 to 7.2) and compared with calculated curves for electrostatic nad van der Waals pressure. Under all conditions studied, interrod spacing decreased with increasing applied pressure, the spacings being smaller at higher ionic strengths. Only small differences were seen when the pH was changed. At ionic strengths near 0.1 M, agreement between theory and experiment is good, but the theory appears to underestimate electrostatic forces at high ionic strengths and to underestimate attractive forces at large interrod spacings (low ionic strengths). It is concluded that an electrostatic-van der Waals force balance can explain stability in tobacco mosaic virus gels near physiological conditions and can provide a good first approximation elsewhere.
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Abstract
Repulsive pressure has been measured as a function of lattice spacing in gels of tobacco mosaic virus (TMV) and in the filament lattice of vertebrate striated muscle. External pressures up to ten atm have been applied to these lattices by an osmotic stress method. Numerical solutions to the Poisson-Boltzmann equation in hexagonal lattices have been obtained and compared to the TMV and muscle data. The theoretical curves using values for k calculated from the ionic strength give a good fit to experimental data from TMV gels, and an approximate fit to that from the muscle lattice, provided that a charge radius for the muscle thick filaments of approximately 16 nm is assumed. Variations in ionic strength, sarcomere length and state of the muscle give results which agree qualitatively with the theory, though a good fit between experiment and theory in the muscle case will clearly require consideration of other types of forces. We conclude that Poisson-Boltzmann theory can provide a good first approximation to the long-range electrostatic forces operating in such biological gel systems.
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