10,843 research outputs found
Structure and mobility of cyclohexane as a solvent for Trans-Polyisoprene
Solutions of {\it trans}polyisoprene in cyclohexane are investigated in
atomistic detail at different compositions at two different temperatures. We
investigate the influence of polymer concentration on the dynamics of the
solvent molecules and the structure of the solvation shell. The double bonds
along the polymer backbone are preferentially approached by the solvent
molecules. The mobility of cyclohexane molecules decreases with increasing
polymer concentration at ambient conditions. The reorientation of molecules
becomes more anisotropic with concentration as the polymer hinders the
reorientation of the molecular plane. At elevated temperatures the influence of
the polymer is weaker and the reorientation of the solvent is more isotropic.
Additionally, a fast and efficient way to set up atomistic simulations is shown
in detail in which the initial simulations increase in length and in the
simulation time-step. The excess energy from initial overlaps is removed by
resetting the velocities at regular intervals.Comment: 6 pages, 3 figure
Automatic interface measurement and analysis
A technique for detecting and measuring the interface between two categories in classified scanner data is described together with two application demonstrations. Measurements were found to be accurate to 1.5% root mean square error on features of known length while comparison of measurements made using the technique on LANDSAT data to opisometer measurements on 1:24,000 scale maps shows excellent agreement. Application of the technique to two frames of LANDSAT data classified using a two channel, two class classifier resulted in a computation of 64 km annual decrease in shoreline length. The tidal shoreline of a portion of Alabama was measured using LANDSAT data. Based on the measurement of this portion, the total tidal shoreline length of Alabama is estimated to be 1313 kilometers
Shoreline as a controlling factor in commercial shrimp production
An ecological model was developed that relates marsh detritus export and shrimp production, based on the hypothesis that the shoreline is a controlling factor in the production of shrimp through regulation of detritus export from the marsh. LANDSAT data were used to develop measurements of shoreline length and area of marsh having more than 5.0 km shoreline/sq km for the coast of Louisiana, demonstrating the capability of remote sensing to provide important geographic information. These factors were combined with published tidal ranges and salinities to develop a mathematical model that predicted shrimp production for nine geographic units of the Louisiana coast, as indicated by the long term average commercial shrimp yield. The mathematical model relating these parameters and the shrimp production is consistent with an energy flow model describing the interaction of detritus producing marshlands with shrimp nursery grounds and inshore shrimping areas. The analysis supports the basic hypothesis and further raises the possibility of applications to coastal zone management requirements
Mellin Amplitudes for Fermionic Conformal Correlators
We define Mellin amplitudes for the fermion-scalar four point function and
the fermion four point function. The Mellin amplitude thus defined has multiple
components each associated with a tensor structure. In the case of three
spacetime dimensions, we explicitly show that each component factorizes on
dynamical poles onto components of the Mellin amplitudes for the corresponding
three point functions. The novelty here is that for a given exchanged primary,
each component of the Mellin amplitude may in general have more than one series
of poles. We present a few examples of Mellin amplitudes for tree-level Witten
diagrams and tree-level conformal Feynman integrals with fermionic legs, which
illustrate the general properties.Comment: 28 pages + Appendices, 8 figure
Thinking Outside the Box: Using Computer Science Skills to Make Sense of the Biology of Life
While I liked coding and the logical aspects of computer programming, my gut was telling me I hadn\u27t quite found my niche yet. In what field could my computer science skills make a difference while also providing me with challenging problems to solve? As these questions percolated through my subconscious, I came across a brief article about a field called “bioinformatics.
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