Study made of anodized aluminum circuit boards

Hard coated aluminum circuit boards demonstrate the feasibility of obtaining an electrical power circuit of high packaging density with very high thermal conductivity and mechanical strengths

Novel self-assembled morphologies from isotropic interactions

We present results from particle simulations with isotropic medium range interactions in two dimensions. At low temperature novel types of aggregated structures appear. We show that these structures can be explained by spontaneous symmetry breaking in analytic solutions to an adaptation of the spherical spin model. We predict the critical particle number where the symmetry breaking occurs and show that the resulting phase diagram agrees well with results from particle simulations.Comment: 4 pages, 4 figure

Modular Solutions to Equations of Generalized Halphen Type

Solutions to a class of differential systems that generalize the Halphen system are determined in terms of automorphic functions whose groups are commensurable with the modular group. These functions all uniformize Riemann surfaces of genus zero and have $q$--series with integral coefficients. Rational maps relating these functions are derived, implying subgroup relations between their automorphism groups, as well as symmetrization maps relating the associated differential systems.Comment: PlainTeX 36gs. (Formula for Hecke operator corrected.

Using the uncertainty principle to design simple interactions for targeted self-assembly

We present a method that systematically simplifies isotropic interactions designed for targeted self-assembly. The uncertainty principle is used to show that an optimal simplification is achieved by a combination of heat kernel smoothing and Gaussian screening of the interaction potential in real and reciprocal space. We use this method to analytically design isotropic interactions for self-assembly of complex lattices and of materials with functional properties. The derived interactions are simple enough to narrow the gap between theory and experimental implementation of theory based designed self-assembling materials

EUV-TEC proxy to describe ionospheric variability using satellite-borne solar EUV measurements

An updated version of a proxy, termed EUV-TEC, describing the global total primary photoionisation is calculated from satellite-borne EUV measurements assuming a model atmosphere consisting of four major atmospheric constituents. Regional number densities of the background atmosphere are taken from the NRLMSISE-00 climatology. For calculation the Lambert-Beer law is used to describe the decrease of the radiation along their way through the atmosphere. The EUV-TEC proxy thus describes the ionospheric response to solar EUV radiation and its variability. EUV-TEC is compared against the global mean total electron content (TEC), a fundamental ionospheric parameter created from vertical TEC maps derived from GPS data. Strong correlation between these indices is found on different time scales. Results show that the EUV-TEC proxy represents the ionsopheric variability better than the conventional solar index F10.7 does, especially during high and moderate solar activity

Using force covariance to derive effective stochastic interactions in dissipative particle dynamics

There exist methods for determining effective conservative interactions in coarse grained particle based mesoscopic simulations. The resulting models can be used to capture thermal equilibrium behavior, but in the model system we study do not correctly represent transport properties. In this article we suggest the use of force covariance to determine the full functional form of dissipative and stochastic interactions. We show that a combination of the radial distribution function and a force covariance function can be used to determine all interactions in dissipative particle dynamics. Furthermore we use the method to test if the effective interactions in dissipative particle dynamics (DPD) can be adjusted to produce a force covariance consistent with a projection of a microscopic Lennard-Jones simulation. The results indicate that the DPD ansatz may not be consistent with the underlying microscopic dynamics. We discuss how this result relates to theoretical studies reported in the literature.Comment: 10 pages, 10 figure

Facilitation shifts paradigms and can amplify coastal restoration efforts

Restoration has been elevated as an important strategy to reversethe decline of coastal wetlands worldwide. Current practice in restorationscience emphasizes minimizing competition between outplantedpropagules to maximize planting success. This paradigmpersists despite the fact that foundational theory in ecology demonstratesthat positive species interactions are key to organism successunder high physical stress, such as recolonization of bare substrate. Asevidence of how entrenched this restoration paradigm is, our surveyof 25 restoration organizations in 14 states in the United States revealedthat >95% of these agencies assume minimizing negative interactions(i.e., competition) between outplants will maximize propagulegrowth. Restoration experiments in both Western and Eastern Atlanticsalt marshes demonstrate, however, that a simple change in plantingconfiguration (placing propagules next to, rather than at adistance from, each other) results in harnessing facilitation and increasedyields by 107% on average. Thus, small adjustments in restorationdesign may catalyze untapped positive species interactions,resulting in significantly higher restoration success with no addedcost. As positive interactions between organisms commonly occur incoastal ecosystems (especially in more physically stressful areas likeuncolonized substrate) and conservation resources are limited, transformationof the coastal restoration paradigm to incorporate facilitationtheory may enhance conservation efforts, shoreline defense, andprovisioning of ecosystem services such as fisheries production