Physical Sciences and Mathematics Commons^™

The Humanitarian Foss Project, Ralph A. Morelli, Allen Tucker, Trishan R. De Lanerolle

Faculty Scholarship

The Humanitarian Free and Open Source Software (Humanitarian FOSS) Project is primarily an educational project whose goal is to engage more undergraduates in building free and open source software (FOSS) that benefits their community. Over the past four years, increasing numbers of undergraduates and computer science programs have been inspired by the Humanitarian FOSS project to make significant contributions to several active open source software development projects that have benefited organizations such as the Portland, Maine Ronald McDonald House, and the New York City Salvation Army. This article provides examples of several Humanitarian FOSS projects and describes other initiatives aimed …

Sharp Weighted Estimates For Classical Operators [Post-Print], David Cruz-Uribe Sfo, José María Martell, Carlos Perez

Faculty Scholarship

See abstract at: http://www.sciencedirect.com/science/article/pii/S0001870811003136

Testing Quantum Randomness In Single-Photon Polarization Measurements With The Nist Test Suite, David Branning, Matthew Bermudez

Faculty Scholarship

A binary sequence was constructed from 1.7×10⁷ polarization measurements of single photons from a spontaneous parametric downconversion source, under pumping conditions similar to those used in optical quantum cryptography. To search for correlations in the polarization measurement outcomes, we subjected the sequence to a suite of tests developed at the National Institute of Standards and Technology (NIST) for the assessment of algorithmic random-number generators. The bias of the sequence was low enough to allow all fifteen tests to be applied directly to the polarization outcomes without using any numerical unbiasing procedures. No statistically significant deviations from randomness were observed, …

Van Der Waals-London Dispersion Interaction Framework For Experimentally Realistic Carbon Nanotube Systems, Roger H. French

Faculty Scholarship

A system's van der Waals–London dispersion interactions are often ignored, poorly understood, or crudely approximated, despite their importance in determining the intrinsic properties and intermolecular forces present in a given system. There are several key barriers that contribute to this issue: 1) lack of the required full spectral optical properties, 2) lack of the proper geometrical formulation to give meaningful results, and 3) a perception that a full van der Waals–London dispersion calculation is somehow unwieldy or difficult to understand conceptually. However, the physical origin of the fundamental interactions for carbon nanotube systems can now be readily understood due to …

Long Range Interactions In Nanoscale Science, Roger H. French

Faculty Scholarship

Our understanding of the “long range” electrodynamic, electrostatic, and polar interactions that dominate the organization of small objects at separations beyond an interatomic bond length is reviewed. From this basic-forces perspective, a large number of systems are described from which one can learn about these organizing forces and how to modulate them. The many practical systems that harness these nanoscale forces are then surveyed. The survey reveals not only the promise of new devices and materials, but also the possibility of designing them more effectively.

Optically Anisotropic Infinite Cylinder Above An Optically Anisotropic Half Space: Dispersion Interaction Of A Single-Walled Carbon Nanotube With A Substrate, Roger H. French

Faculty Scholarship

A complete form of the van der Waals dispersion interaction between an infinitely long anisotropic semiconducting/insulating thin cylinder and an anisotropic half space is derived for all separations between the cylinder and the half space. The derivation proceeds from the theory of dispersion interactions between two anisotropic infinite half spaces as formulated in Phys. Rev. A 71, 042102 (2005). The approach is valid in the retarded as well as nonretarded regimes of the interaction and is coupled with the recently evaluated ab initio dielectric response functions of various semiconducting/insulating single wall carbon nanotubes, enables the authors to evaluate the strength …

Two-Dimensional Descent Through A Compressible Atmosphere: Sequential Deceleration Of An Unpowered Load, Mark P. Silverman

Faculty Scholarship

Equations, based on Rayleigh's drag law valid for high Reynolds number, are derived for two-dimensional motion through a compressible atmosphere in isentropic equilibrium, such as characterizes the Earth's troposphere. Solutions yield horizontal and vertical displacement, velocity, and acceleration as a function of altitude and ground-level temperature. An exact analytical solution to the equations linearized in the aero-thermodynamic parameter is given; in general the equations must be solved numerically. The theory, applied to the unpowered fall of a large aircraft stabilized to flat descent by symmetrical, sequential deployment of horizontal and vertical decelerators, shows that such an aircraft can be brought …

Pursuing Geoengineering For Atmospheric Restoration, James Salzman, Robert B. Jackson

Faculty Scholarship

Geoengineering is fraught with problems, but research on three approaches could lead to the greatest climate benefits with the smallest chance of unintentional environmental harm. The authors propose a model for thinking about geoengineering based on the concept of restoration, suggesting the term “atmospheric restoration.” Under this model geoengineering efforts are prioritized based on three principles: to treat the cause of the disease itself, to reduce the chance of harm, and to prioritize activities with the greatest chance of public acceptance.

Based on these principles, the authors propose three forms of geoengineering that could provide the greatest climate benefits with …

Designing Payments For Ecosystem Services, James Salzman

Faculty Scholarship

This Policy Series by James Salzman brings attention to a rapidly developing phenomenon—payments for ecosystem services (PES).

Salzman, the Samuel F. Mordecai Professor of Law and the Nicholas Institute Professor of Environmental Policy at Duke University, explains when and where ecosystem services can be provided by voluntary markets rather than government actions. The key to understanding how PES work is rooted in the basis of any voluntary market transaction—gains from trade. One party agrees to take action because another party offers an incentive. Both parties benefit. A beekeeper, for example, brings her hives to an orchard to provide pollination services …