Bulletin of the American Physical Society
2005 Joint New England Sections of APS and AAPT Spring Meeting
Friday–Saturday, April 1–2, 2005; Cambridge, MA
Session G: General |
Hide Abstracts |
Chair: Karl Ludwig, BU Room: Room 4-237 |
Saturday, April 2, 2005 1:30PM - 1:45PM |
G.00001: Violation of Scale Invariance in the Laminar-Turbulent Transition in Gases Amador Muriel For the past 150 years, it has been a tenet of the continuum model of hydrodynamics that the dimensionless critical Reynolds number is the sole discriminant of laminar-turbulent transition, irrespective of the hydrodynamic medium. So for the same apparatus, such as a pipe gas efflux apparatus, it is asserted that the critical Reynolds number, $Re_c =\rho v_c d/\eta $ , where $\rho $ is the density, $v_c $ is the critical velocity, $d$ is the diameter of a tube, and $\eta $ is the dynamic viscosity, should be the same for all gases. This tenet is supported by (1) a re-scaling of the Navier-Stokes equation, and (2) experiments which have heretofore been accurate only to some 10-30{\%}. New experiments using rapid pressure measurements with a sampling rate of every millisecond ( S. Novopashin, A. Muriel., Phys. Letters A 335 (2005) 435 ), and vacuum technology equipment ( L. Hinkle, A. Muriel, Phys. Letters A, to be published ) show that this scale invariance is not true for the laminar-turbulent transition, thus questioning the basic assumption of continuum theory that the precise molecular nature of the gas used in the experiment is irrelevant. We will display results which are molecule-dependent, raising questions on the exclusive use the Navier-Stokes equation as the defining equation for the study of turbulence. [Preview Abstract] |
Saturday, April 2, 2005 1:45PM - 2:00PM |
G.00002: Service Learning In Physics: The Consultant Model David Guerra Each year thousands of students across the country and across the academic disciplines participate in service learning. Unfortunately, with no clear model for integrating community service into the physics curriculum, there are very few physics students engaged in service learning. To overcome this shortfall, a consultant based service-learning program has been developed and successfully implemented at Saint Anselm College (SAC). As consultants, students in upper level physics courses apply their problem solving skills in the service of others. Most recently, SAC students provided technical and managerial support to a group from Girl's Inc., a national empowerment program for girls in high-risk, underserved areas, who were participating in the national FIRST Lego League Robotics competition. In their role as consultants the SAC students provided technical information through brainstorming sessions and helped the girls stay on task with project management techniques, like milestone charting. This consultant model of service-learning, provides technical support to groups that may not have a great deal of resources and gives physics students a way to improve their interpersonal skills, test their technical expertise, and better define the marketable skill set they are developing through the physics curriculum. [Preview Abstract] |
Saturday, April 2, 2005 2:00PM - 2:15PM |
G.00003: Physics of the environment: possible Sumatra Tsunami warning times for large animals in Sri Lanka David G. Browning, Peter M. Scheifele, William A. VonWinkle There has previously been significant anecdotal evidence that animals can anticipate or sense seismic events. It is known that large animals, specifically elephants, sense and utilize low frequency sound. The object of this paper is to estimate the possible warning times that large animals in Sri Lanka could have had of the Sumatra Tsunami, assuming they could sense low frequency wave transmission from the initial earthquake arriving by either atmospheric, ocean, or bottom paths. The atmospheric path appears to be the least efficient due to relatively high attenuation and poor coupling to the source. It would also give the shortest warning time: approximately 30 minutes. The ocean path via the deep sound channel, which has been shown by a previous Bermuda experiment to be an efficient means of coupling seismic energy to an island, would give a warning time of more than 1.5 hours. The bottom path(s), which gave strong received signals at a Sri Lanka seismic station, would give a warning time of about 2 hours. These estimates should provide a context for animal behavior reports. [Preview Abstract] |
Saturday, April 2, 2005 2:15PM - 2:30PM |
G.00004: Blackbody Radiation: Kirchhoff's Error Propagates Beyond Einstein Pierre-Marie Robitaille A perfect absorber (approximated by graphite) is a blackbody. However, in 1860, Kirchhoff inappropriately concluded that a perfect reflector could also yield blackbody radiation. This led to the idea that such radiation was independent of the nature of the emitting object. Both Planck and Einstein, without sufficiently considering Kirchhoff's experimental work and theoretical conclusion, adopted the concept of universality--a view that persists to this day. In 1917, Einstein reinforced this concept. Assuming transitions between two states and equilibrium with a Wien's radiation field, Einstein was able to derive Planck's equation for blackbody radiation. Unfortunately, there is no experimental evidence that a radiation field which obeys Wien's Law can ever be produced in the absence of condensed matter. Consequently, under closer consideration, Einstein's derivation, far from affirming universality, directly invokes the presence of a solid (through the need to generate Wien's radiation field) and thereby restricts blackbody radiation to this state of matter. The belief that blackbody radiation is universal is not supported in the experimental setting. [Preview Abstract] |
Saturday, April 2, 2005 2:30PM - 2:45PM |
G.00005: Quantum explanation of Brownian motion Elias P. Gyftopoulos In ``Investigations of the Brownian movement'', Einstein bases his arguments ``on the molecular-kinetic theory of heat.'' In this article, I provide incontrovertible evidence against the molecular-kinetic conception of heat, and an explanation of Brownian motion that differs from all procedures in the archival literature. The explanation is based on two revolutionary theories, one thermodynamic, and the other quantum mechanical. No heat is involved because heat is a mode of interaction and not a property of any system. In a system that consists of constant amounts and volumes of a solvent and an insoluble solute, the shapes of the two volumes change continuously in time as solvent and solute try to interpenetrate each other as a result of differences in total potentials. The shape changes affect the energy eigenstates that enter the expressions of the stable equilibrium states of solvent and solute. A nonlinear quantum mechanical equation of motion that we conceived redistributes the constituents of the solvent and the solute to the continuously varying density operators without affecting the energy, the amounts of constituents, the volumes, and the entropy of either subsystem. The equation of motion is neither the Schroedinger nor the von Neumann equation because the effects of shape changes are nonunitary. The processes just cited are everlasting because the favorable but ineffective total potential differences are everlasting. [Preview Abstract] |
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