P. Fraundorf

Publications (102) View all

• Source

  Available from: adsabs.harvard.edu

  Article: Microcharacterization of "Brownlee particles": Features which distinguish interplanetary dust from meteorites.

  P. Fraundorf, J. Shirck
  LPI Contributions. 01/2013; 363:19-23.
• Article: A fun intro to 1D kinematics

  P. Fraundorf
  [show abstract] [hide abstract]
  ABSTRACT: Introductory physics texts often start with: (i) time as an implicitly universal-variable, and (ii) the oddly mass-independent acceleration-due-to-gravity near earth's surface, as givens with no larger context. In this short note, we take an "engineering" rather than a "physics" approach and (for those who might enjoy it) invoke modern concepts to tell a story about: (a) time as a quantity like position that depends on one's choice of yardsticks & clocks, and (b) the geometric origins of gravitational acceleration. The note is designed to tantalize students interested in the subject with predictive equations within range of their math-background, while for students otherwise interested it provides context while delivering the good-news that {\em their} course involves only low-speed approximations.
  06/2012;
• Article: Zero-loss/deflection map analysis

  P. Fraundorf, K. Pisane, E. Mandell, R. Collins
  [show abstract] [hide abstract]
  ABSTRACT: Experimental plots of the fraction of detected electrons removed from the zero-loss peak, versus the fraction of incident electrons scattered outside of the objective aperture, can serve as a robust fingerprint of object-contrast in an energy filtered transmission electron microscope (EFTEM). Examples of this, along with the first in a series of models for interpreting the resulting patterns, were presented at the August 2010 meeting of the Microscope Society of America meeting in Portland, Oregon, and published in {\em Microscopy and MicroAnalysis} {\bf 16}, Supplement 2, pages 1534-1535 by Cambridge University Press.
  03/2012;
• Source

  Available from: ArXiv

  Article: A multiple of 12 for Avogadro

  P. Fraundorf
  [show abstract] [hide abstract]
  ABSTRACT: The new International System of Units may let us select an integer value for Avogadro's number. Some might prefer an integer that's divisible by 12, so that an integer number of $^{12}C$ atoms may be associated (at least to first order) with a gram's mass. For educational as well as practical reasons it may also help to choose a {\em physically-meaningful} definition, within measurement error of the current numeric value. Cubes of diamond face-centered-cubic Si and (much rarer) face-centered-cubic C have been proposed, but these structures don't have naturally occurring facets (or numbers of atoms generally divisible by 12). We show here that graphite prisms formed by stacking $m$ hexagonal graphene sheets, with $m \equiv 51,150,060$ carbon-12 atoms on each side, are a natural solution to this challenge.
  01/2012;
• Source

  Available from: ArXiv

  Article: Metric-first & entropy-first surprises

  P. Fraundorf
  [show abstract] [hide abstract]
  ABSTRACT: Established idea-sets don't update seamlessly. The tension between new and old views of nature is e.g. documented in Galileo's dialogs and now present in many fields. However the science of Bayesian model-selection has made recent strides in both life & physical sciences, in effect suggesting that we look to models which are quantitatively {\em surprised least} by present-day observations. We illustrate the relevance of this to physics-education with a qualitative look at two paradigm-shifts, namely from {\bf Lorentz-transform to metric-equation} descriptions of motion in space-time, and from {\bf classical to statistical thermodynamics} with help from Boltzmann's choice-multiplicity & Shannon's uncertainty. Connections of the latter to {\bf correlation measures} behind available-work, evolving complexity, and model-selection relevant to physics undergrads are also explored. New strategies are exemplified with Appendices {\em for teachers} on: anyspeed traffic-laws & 3-vector velocity-addition, the energy-momentum half-plane lost to finite lightspeed, the modern distinction between proper & geometric accelerations, metric-first kinematics with acceleration & differential-aging, quantifying risk with a handful of coins, effective number of choices, available work in bits, reversible-thermalization of life's power-stream, and choice-multiplicity measures of layered complex-system health.
  06/2011;