Physical Sciences and Mathematics Commons^™

Towards Granular Hydrodynamics In Two-Dimensions, E.L. Grossman, T. Zhou, E. Ben-Naim

Eli Ben-Naim

We study steady-state properties of inelastic gases in two-dimensions in the presence of an energy source. We generalize previous hydrodynamic treatments to situations where high and low density regions coexist. The theoretical predictions compare well with numerical simulations in the nearly elastic limit. It is also seen that the system can achieve a nonequilibrium steady-state with asymmetric velocity distributions, and we discuss the conditions under which such situations occur.

Nmr And Vortex Lattice Melting In Yba2cu3o7, Charles Recchia, J Martindale, C Pennington, W Hults, J Smith

Charles H Recchia

No abstract provided.

Local Nonequilibrium Transport Models, Sergey Sobolev

Sergey Sobolev

No abstract provided.

Local Non-Equilibrium Diffusion Effects On The Kinetic Phase Boundaries In Solidification, Sergey Sobolev

Sergey Sobolev

No abstract provided.

The Time Evolution Of Unstable Monopoles, Moataz Emam

Moataz Emam

No abstract provided.

Coarsening And Persistence In The Voter Model, E. Ben-Naim, L. Frachebourg, P.L. Krapivsky

Eli Ben-Naim

No abstract provided.

Gaussian Phase Approximation For Evaluating The Decay Of Nmr Spin Echoes, Charles Recchia, K Gorny, C Pennington

Charles H Recchia

No abstract provided.

Effects Of Local Non-Equilibrium Solute Diffusion On Rapid Solidification Of Alloys, Sergey Sobolev

Sergey Sobolev

A conceptual foundation for the study of local non-equilibrium solute diffusion under rapid solidifica- tion conditions is proposed. The model takes into account the relaxation to local equilibrium of the solute flux and incorporates two diffusion speeds, VDb, the bulk liquid diffusion speed, and VDi, the interface diffusive speed, as the most important parameters governing the solute concentration in the liquid phase and solute partitioning. The analysis of the model predicts complete solute trapping and the transition to a purely thermally controlled solidification, which occur abruptly when the interface velocity V equals the bulk liquid diffusion speed VDb. The abrupt …

The Local-Nonequilibrium Temperature Field Around The Melting And Crystallization Front Induced By Picosecond Pulsed Laser Irradiation, Sergey Sobolev

Sergey Sobolev

The local-nonequilibrium model for heat transport around melting and crystallization zone induced by ultrafast laser irradiation is considered. The model predicts strong overheating during melting of the material near the interface. Moreover, the local-nonequilibrium effects lead to an interface temperature gradient steeper than expected from the classical heat flow calculations. Possible modification of the kinetics of melting to include the relaxation effects is also discussed.

Applications Of Extended Thermodynamics ...Part Iii., Sergey Sobolev

Sergey Sobolev

No abstract provided.

Trajectory Mapping And Applications To Data From The Upper Atmosphere Research Satellite, Gary A. Morris, Mark R. Schoeberl, Lynn C. Sparling, Paul A. Newman, Leslie R. Lait, Lee Elson, Joe Waters, Robert A. Suttie, Aidan Roche, Jack Kumer, James M. Russell Iii

Gary A. Morris

The problem of creating synoptic maps from asynoptically gathered trace gas data has prompted the development of a number of schemes. Most notable among these schemes are the Kalman filter, the Salby-Fourier technique, and constituent reconstruction. This paper explores a new technique called "trajectory mapping." Trajectory mapping creates synoptic maps from asynoptically gathered data by advecting measurements backward or forward in time using analyzed wind fields. A significant portion of this work is devoted to an analysis of errors in synoptic trajectory maps associated with the calculation of individual parcel trajectories. In particular, we have considered (1) calculational errors; (2) …

Vortex Dynamics In Single Crystal Yba2cu3o7 Probed By 63cu Nuclear Spin Echo Measurements In The Presence Of Transport Current Pulses, Charles Recchia, C Pennington, H Haughlin, G Lafyatis

Charles H Recchia

No abstract provided.

Local Non-Equilibrium Model For Rapid Solidification Of Undercooled Melts, Sergey Sobolev

Sergey Sobolev

No abstract provided.

Two Temperature Stefan Problem, Sergey Sobolev

Sergey Sobolev

No abstract provided.

Applications Of Extended Thermodynamics ...Part I., Sergey Sobolev

Sergey Sobolev

No abstract provided.

Applications Of Extended Thermodynamics ...Part Ii., Sergey Sobolev

Sergey Sobolev

No abstract provided.

Kinetics Of Clustering In Traffic Flows, E. Ben-Naim, P. L. Krapivsky, S. Redner

Eli Ben-Naim

We study a simple aggregation model that mimics the clustering of traffic on a one-lane roadway. In this model, each ``car'' moves ballistically at its initial velocity until it overtakes the preceding car or cluster. After this encounter, the incident car assumes the velocity of the cluster which it has just joined. The properties of the initial distribution of velocities in the small velocity limit control the long-time properties of the aggregation process. For an initial velocity distribution with a power-law tail at small velocities, $\pvim$ as $v \to 0$, a simple scaling argument shows that the average cluster size …

More On Twinkling, Terry L. Smith, Jay S. Huebner

Terry L. Smith

Addendum to Why Magnification Works , The Physics Teacher, 1994, 32, 102.

Why Magnification Works, Terry L. Smith, Jay S. Huebner

Terry L. Smith

The simplest way to magnify the view of a small object is to bring the object closer to the eye, and of course science teachers know about magnifying glasses, telescopes, and microscopes.But why magnification works seems intuitive and is not usually explained to our students. We present here a few ideas on magnification that we use in our classroom and some general information on vision that we hope will be helpful to other teachers.

Two-Temperature Discrete Model For Nonlocal Heat Conduction, Sergey Sobolev

Sergey Sobolev

The two-temperature discrete model for heat conduction in heterogeneous media is proposed. It is shown that the discrete model contains as limiting cases both hyperbolic and parabolic heat conduction equations for propagative and diffusive regimes, respectively. To obtain these limiting cases two different laws of continuum limit have been introduced. The evolution of the two-temperature system comprises three stages with distinct time scales : fast relaxation of each subsystem to local equilibrium, energy exchange between the subsystems and classical hydrodynamics.

Multi-Ball Collisions, Terry L. Smith, Jay S. Huebner

Terry L. Smith

Explanation to use the "double-ball" demonstration as a model for the supernova core bounce.

Transport Processes And Traveling Waves In Systems With Local Nonequilibrium, Sergey Sobolev

Sergey Sobolev

No abstract provided.

General Relativity Is Dead, Milan Meszaros

Milan Meszaros physicist

The intent of the present study is to analize standard cosmology in an immanent mathematical-critical way. First of all, the fundamental statements of this cosmological model will be investigated themselves as well as their relevation to the theory. Further aims are to reveal the interdependence of different physical disciplines, confrontation of various observations, to elucidate the correlations between observed data and theory and, finally, to analyze this cosmology from the point of view of self-consistency.

The study discusses the status of the standard modell.

A Simple Monochromatic Spark Discharge Light-Source, Chin Oi Hoong

Chin Oi Hoong

Spark light illumination has been used in high-speed photog-raphy since the beginning ofthe century and various designs ofthe spark discharge light source have since been reportedr with spark duration ranging from nanoseconds to millisec-onds. We report here a simple and easy to build spark dis-charge tube for operation as a monochromatic point light source. The design and construction ofthe spark discharge tube is shown in Fig. 1. The sharp-tip solid cone anode is made of stainless steel which is screwed onto a brass rod connected A compact spark discharge tube operated as a monochromatic light source at 587.5 nm is …

Measurements Of Electron Energy Distribution In An Argon Positive Column, Chin Oi Hoong

Chin Oi Hoong

The argon positive column plasma of a cold cathode glow discharge is studied using a pulsed single Langmuir Probe technique. It is observed thatthe energy distribution of the electrons in the posotive column is non-maxwellian at a gas pressure of 0.5 mbar. An increase in the gas pressure seems to make the distribution more Maxwellian.