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Selected Works

2007

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Articles 31 - 52 of 52

Full-Text Articles in Physics

Measurement Of Cp-Violating Asymmetries In The B0 --> K+K−K0 Dalitz Plot, Stefan Spanier Dec 2006

Measurement Of Cp-Violating Asymmetries In The B0 --> K+K−K0 Dalitz Plot, Stefan Spanier

stefan spanier

No abstract provided.


Polyaniline On Crystalline Silicon Heterojunction Solar Cells, Weining Wang, E. A. Schiff Dec 2006

Polyaniline On Crystalline Silicon Heterojunction Solar Cells, Weining Wang, E. A. Schiff

Weining Wang, Ph.D.

No abstract provided.


Self-Heating In Compost Piles Due To Biological Effects, Tim Marchant Dec 2006

Self-Heating In Compost Piles Due To Biological Effects, Tim Marchant

Tim Marchant

The increase in temperature in compost piles/landfill sites due to micro-organisms undergoing exothermic reactions is modelled. A simplified model is considered in which only biological self-heating is present. The heat release rate due to biological activity is modelled by a function which is a monotonic increasing function of temperature over the range 0⩽T⩽a, whilst for T⩾a it is a monotone decreasing function of temperature. This functional dependence represents the fact that micro-organisms die or become dormant at high temperatures. The bifurcation behaviour is investigated for 1-d slab and 2-d rectangular slab geometries. In both cases there ...


Solitary Wave Interaction For A Higher-Order Nonlinear Schrodinger Equation, Tim Marchant Dec 2006

Solitary Wave Interaction For A Higher-Order Nonlinear Schrodinger Equation, Tim Marchant

Tim Marchant

Solitary wave interaction for a higher-order version of the nonlinear Schrödinger (NLS) equation is examined. An asymptotic transformation is used to transform a higher-order NLS equation to a higher-order member of the NLS integrable hierarchy, if an algebraic relationship between the higher-order coefficients is satisfied. The transformation is used to derive the higher-order one- and two-soliton solutions; in general, the N-soliton solution can be derived. It is shown that the higher-order collision is asymptotically elastic and analytical expressions are found for the higher-order phase and coordinate shifts. Numerical simulations of the interaction of two higher-order solitary waves are also performed ...


Dust And Atomic Gas In Dwarf Irregular Galaxies Of The M81 Group: The Sings And Things View, F. Walter, John Cannon, H. Roussel, G. Bendo, D. Calzetti, D. Dale, B. Draine, G. Helou, R. Kennicutt, G. Rieke, L. Armus, C. Engelbracht, K. Gordon, D. Hollenbach, J. Lee, A. Li, M. Meyer, J. Moustakas, E. Murphy, M. Regan, J-D. Smith, E. Brinks, W.J. Deblok, F. Bigiel, M. Thornley Dec 2006

Dust And Atomic Gas In Dwarf Irregular Galaxies Of The M81 Group: The Sings And Things View, F. Walter, John Cannon, H. Roussel, G. Bendo, D. Calzetti, D. Dale, B. Draine, G. Helou, R. Kennicutt, G. Rieke, L. Armus, C. Engelbracht, K. Gordon, D. Hollenbach, J. Lee, A. Li, M. Meyer, J. Moustakas, E. Murphy, M. Regan, J-D. Smith, E. Brinks, W.J. Deblok, F. Bigiel, M. Thornley

John Cannon

No abstract provided.


Domain Walls, The Extended Superconformal Algebra, And The Supercurrent, T Clark, M Nitta, Tonnis Ter Veldhuis Dec 2006

Domain Walls, The Extended Superconformal Algebra, And The Supercurrent, T Clark, M Nitta, Tonnis Ter Veldhuis

Tonnis ter Veldhuis

No abstract provided.


Optical Enhancement In Semitransparent Polymer Photovoltaic Cells, Gm Ng, El Kietzke, T Kietzke, Lw Tan, Pk Liew, F.R. Zhu Dec 2006

Optical Enhancement In Semitransparent Polymer Photovoltaic Cells, Gm Ng, El Kietzke, T Kietzke, Lw Tan, Pk Liew, F.R. Zhu

Professor ZHU, Fu Rong

No abstract provided.


Asymptotic Solitons On A Non-Zero Mean Level., Tim Marchant Dec 2006

Asymptotic Solitons On A Non-Zero Mean Level., Tim Marchant

Tim Marchant

The collision of solitary waves for a higher-order modified Korteweg-de Vries (mKdV) equation is examined. In particular, the collision between solitary waves with sech-type and algebraic (which only exist on a non-zero mean level) profiles is considered. An asymptotic transformation, valid if the higher-order coefficients satisfy a certain algebraic relationship, is used to transform the higher-order mKdV equation to an integrable member of the mKdV hierarchy. The transformation is used to show that the higher-order collision is asymptotically elastic and to derive the higher-order phase shifts. Numerical simulations of both elastic and inelastic collisions are performed. For the example covered ...


Commercial Water Auditing In Stella, Stephen Mecca, S. Mecca Dec 2006

Commercial Water Auditing In Stella, Stephen Mecca, S. Mecca

Stephen J. Mecca

Stella has been successfully used to model water supply systems [1] including the representation of residential demand [2] in such systems (Stella is a product of ISEE Systems, Hanover, NH USA.) This paper documents the use of this modeling tool in simulating demand from several appliances common to commercial water users and applying this technique to commercial water auditing. The application of the model to the audits of six commercial organizations is presented. The model is being used for water management/conservation studies but also has potential for representing commercial water demand in more comprehensive supply system models.


Numerical Simulation Of Contaminant Flow In A Wool Scour Bowl., Tim Marchant Dec 2006

Numerical Simulation Of Contaminant Flow In A Wool Scour Bowl., Tim Marchant

Tim Marchant

Wool scouring is the process of washing dirty wool after shearing. Our model numerically simulates contaminant movement in a wool scour bowl using the advection–dispersion equation. This is the first wool scour model to give time-dependent results and to model the transport of contaminants within a single scour bowl. Our aim is to gain a better understanding of the operating parameters that will produce efficient scouring. Investigating the effects of varying the parameters reveals simple, interesting relationships that give insight into the dynamics of a scour bowl.


Angular Dependent Magnetorestriction Study Of Cecoin5, Catalin Martin, Victor Correa, Kenneth Purcell, Timothy Timothy, Eric Palm, Stanley Tozer, George Schmiedeshoff, J Cooley Dec 2006

Angular Dependent Magnetorestriction Study Of Cecoin5, Catalin Martin, Victor Correa, Kenneth Purcell, Timothy Timothy, Eric Palm, Stanley Tozer, George Schmiedeshoff, J Cooley

George Schmiedeshoff

Using a capacitive dilatometer designed to operate on the rotating stage of a top loading dilution refrigerator probe, we measured the magnetorestriction ( L(H)-L(0))/L(0), of the Heavy Fermion Superconductor CeCoIn5, along all three crystallographic direction, and with the magnetic field applied parallel both to the superconducting ab-planes and to the c-axis. When B||ab, the c-axis magnetorestriction features, besides a sharp jump at the upper critical field, a continuous, second-order like, transition at a lower field, which is consistent with previous observations from specific heat measurements. Our results are consistent with a field induced modulation of ...


An Ultraviolet-To-Radio Broadband Spetral Atlas Of Nearby Galaxies, D. A. Dale, A. Gil De Paz, K. D. Gordon, H. M. Hanson, L. Armus, G. J. Bendo, L. Bianchi, M. Block, S. Boisser, A. Boselli, B. A. Buckalew, V. Buat, D. Burgarella, D. Calzetti, John M. Cannon, C. W. Engelbracht, G. Helou, D. J. Hollenbach, T. H. Jarett, R. C. Kennicutt, C. Leitherer, A. Li, B. F. Madore, D. C. Martin, M. J. Meyer, E. J. Murphy, M. W. Regan, H. Roussel, J-D. T. Smith, M. L. Sosey, D. A. Tilker, F. Walter Dec 2006

An Ultraviolet-To-Radio Broadband Spetral Atlas Of Nearby Galaxies, D. A. Dale, A. Gil De Paz, K. D. Gordon, H. M. Hanson, L. Armus, G. J. Bendo, L. Bianchi, M. Block, S. Boisser, A. Boselli, B. A. Buckalew, V. Buat, D. Burgarella, D. Calzetti, John M. Cannon, C. W. Engelbracht, G. Helou, D. J. Hollenbach, T. H. Jarett, R. C. Kennicutt, C. Leitherer, A. Li, B. F. Madore, D. C. Martin, M. J. Meyer, E. J. Murphy, M. W. Regan, H. Roussel, J-D. T. Smith, M. L. Sosey, D. A. Tilker, F. Walter

John Cannon

No abstract provided.


Imaging Voltage-Dependent Cell Motions With Heterodyne Mach-Zehnder Phase Microscopy, Christopher Fang-Yen, S Oh, Y Park, S Song, H S. Seung, M S. Feld Dec 2006

Imaging Voltage-Dependent Cell Motions With Heterodyne Mach-Zehnder Phase Microscopy, Christopher Fang-Yen, S Oh, Y Park, S Song, H S. Seung, M S. Feld

Christopher Fang-Yen

No abstract provided.


Tomographic Phase Microscopy, W Choi, Christopher Fang-Yen, K Badizadegan, S Oh, N Lue, R R. Dasari, M S. Feld Dec 2006

Tomographic Phase Microscopy, W Choi, Christopher Fang-Yen, K Badizadegan, S Oh, N Lue, R R. Dasari, M S. Feld

Christopher Fang-Yen

No abstract provided.


Significant Suppression Of Ferromagnetism By Hydrostatic Pressure In The Diluted Magnetic Semiconductor Sb2-Xvxte3 With X <~ 0.03, Jeffrey Dyck, T J. Mitchell, A J. Luciana, P C. Quayle, C DrašAr, P LošŤÁK Dec 2006

Significant Suppression Of Ferromagnetism By Hydrostatic Pressure In The Diluted Magnetic Semiconductor Sb2-Xvxte3 With X <~ 0.03, Jeffrey Dyck, T J. Mitchell, A J. Luciana, P C. Quayle, C DrašAr, P LošŤÁK

Jeffrey Dyck

The authors report on the hydrostatic pressure dependence of the magnetotransport properties of ferromagnetic Sb2-xVxTe3 single crystals with x=0.02—0.03. Pressure significantly increases the free hole concentration in these compounds. In turn, the Curie temperature is suppressed by roughly 40%, which goes against many models that would predict an increase in Curie temperature with increasing carrier concentration. These results indicate that the ferromagnetism in these materials is carrier mediated and that a full Ruderman-Kittel-Kasuya-Yosida model that takes into account the oscillatory nature of the indirect exchange interaction among localized spins is needed in order to explain the ...


The Low Co Content Of The Extremely Metal-Poor Galaxy I Zw 18, A. Leroy, John M. Cannon, F. Walter, A. Bolatto, A. Weiss Dec 2006

The Low Co Content Of The Extremely Metal-Poor Galaxy I Zw 18, A. Leroy, John M. Cannon, F. Walter, A. Bolatto, A. Weiss

John Cannon

No abstract provided.


Second Born Approximation And Coulomb Scattering, Br Holstein Dec 2006

Second Born Approximation And Coulomb Scattering, Br Holstein

Barry R Holstein

We examine the problem of calculating higher order contributions to the Coulomb scattering amplitude. To make contact with the well known result, it is necessary to modify the conventional definition of the scattering amplitude.


Precision Measurements Of The Nucleon Strange Form Factors At Q2∼0.1  Gev2, Krishna Kumar Dec 2006

Precision Measurements Of The Nucleon Strange Form Factors At Q2∼0.1  Gev2, Krishna Kumar

Krishna Kumar

We report new measurements of the parity-violating asymmetry APV in elastic scattering of 3 GeV electrons off hydrogen and 4He targets with ⟨θlab⟩≈6.0°. The 4He result is APV=(+6.40±0.23(stat)±0.12(syst))×10-6. The hydrogen result is APV=(-1.58±0.12(stat)±0.04(syst))×10-6. These results significantly improve constraints on the electric and magnetic strange form factors GEs and GMs. We extract GEs=0.002±0.014±0.007 at ⟨Q2⟩=0.077  GeV2, and GEs+0.09GMs=0.007±0.011±0.006 at ⟨Q2⟩=0.109  GeV2, providing new ...


Geometric Theory Of Columnar Phases On Curved Substrates, Christian Santangelo, Vincenzo Vitelli, Randall D. Kamien, David R. Nelson Dec 2006

Geometric Theory Of Columnar Phases On Curved Substrates, Christian Santangelo, Vincenzo Vitelli, Randall D. Kamien, David R. Nelson

Christian Santangelo

We study thin self-assembled columns constrained to lie on a curved, rigid substrate. The curvature presents no local obstruction to equally spaced columns in contrast with curved crystals for which the crystalline bonds are frustrated. Instead, the vanishing compressional strain of the columns implies that their normals lie on geodesics which converge (diverge) in regions of positive (negative) Gaussian curvature, in analogy to the focusing of light rays by a lens. We show that the out of plane bending of the cylinders acts as an effective ordering field.


Modeling Innovation By A Kinetic Description Of The Patent Citation System, Gabor Csardi, Katherine J. Strandburg, Jan Tobochnik, Peter Erdi, Laszlo Zalanyi Dec 2006

Modeling Innovation By A Kinetic Description Of The Patent Citation System, Gabor Csardi, Katherine J. Strandburg, Jan Tobochnik, Peter Erdi, Laszlo Zalanyi

Katherine J. Strandburg

This paper reports results of a network theory approach to the study of the United States patent system. We model the patent citation network as a discrete time, discrete space stochastic dynamic system. From patent data we extract an attractiveness function, A(k, l), which determines the likelihood that a patent will be cited. A(k, l) shows power law aging and perferential attachment, the exponent of the latter is increasing since 1993, suggesting that patent citations are increasingly concentrated on a relatively small number of patents. In particular, our results appear consistent with an increasing patent “thicket”, in which ...


Membrane Fluctuations Around Inclusions, Christian Santangelo, Oded Farago Dec 2006

Membrane Fluctuations Around Inclusions, Christian Santangelo, Oded Farago

Christian Santangelo

The free energy of inserting a protein into a membrane is determined by considering the variation in the spectrum of thermal fluctuations in response to the presence of a rigid inclusion. Both numerically and through a simple analytical approximation, we find that the primary effect of fluctuations is to reduce the effective surface tension, hampering the insertion at low surface tension. Our results, which should also be relevant for membrane pores, suggest (in contrast to classical nucleation theory) that a finite surface tension is necessary to facilitate the opening of a pore.


Digital Elevation Accuracy And Grid Cell Size: Effects On Computed Topographic Attributes, Rob H. Erskine, Timothy R. Green Dec 2006

Digital Elevation Accuracy And Grid Cell Size: Effects On Computed Topographic Attributes, Rob H. Erskine, Timothy R. Green

Timothy R. Green

Terrain attributes are commonly used to explain the spatial variability of agronomic, pedologic, and hydrologic variables. The terrain attributes studied here (elevation, slope, aspect, and curvature) are estimated readily from digital elevation models (DEMs), but questions remain about how the accuracy and sample spacing of the elevation data affect the estimated attributes. The main objective of this study was to quantify differences in each terrain attribute due to factors affecting DEM accuracy and grid cell size. Three data sources were compared: (i) real-time kinematic global positioning system (RTKGPS); (ii) satellite-differentially corrected global positioning system (DGPS); and (iii) U.S. Geological ...