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Graf, Peter

Publications and source records attributed to Graf, Peter.

60 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Simulation Toolkit for Renewable Energy Advanced Materials Modeling

STREAMM is a collection of python classes and scripts that enables and eases the setup of input files and configuration files for simulations of advanced energy materials. The core STREAMM python classes provide a general framework for storing, manipulating and analyzing atomic/molecular coordinates to be used in quantum chemistry and classical molecular dynamics simulations of soft materials systems. The design focuses on enabling the interoperability of materials simulation codes such as GROMACS, LAMMPS and Gaussian.

Sides, Scott↗
DOE OSTI2013

NREL Wind Integrated System Design and Engineering Model

NREL_WISDEM is an integrated model for wind turbines and plants developed In python based on the open source software OpenMDAO. NREL_WISDEM is a set of wrappers for various wind turbine and models that integrate pre-existing models together into OpenMDAO. It is organized into groups each with their own repositories including Plant_CostSE. Plant_EnergySE, Turbine_CostSE and TurbineSE. The wrappers are designed for licensed and non-licensed models though in both cases, one has to have access to and install the individual models themselves before using them in the overall software platform.

Ning, S. Andrew↗
DOE OSTI2013

DAKOTA Driver (WISDEM®) [SWR-13-16]

OpenMDAO driver for DAKOTA (Design Analysis Kit for Optimization and Terascale Applications). This code connects the SANDIA National Laboratory's C++-based DAKOTA optimization and analysis tool with NASA’s python-based openMDAO systems engineering framework. It allows DAKOTA to be used as an openMDAO “Driver”. DAKOTA contains a wide array of advanced sensitivity, uncertainty quantification, and optimization methods. These are now available in a “pluggable” way to any openMDAO based workflow.

Graf, Peter↗
DOE OSTI2013

Dakota Driver

This code connects the SANDIA’a C++-based DAKOTA optimization and analyis tool with NASA’s python-based openMDAO systems engineering framework. It allows DAKOTA to be used as an openMDAO “Driver”. DAKOTA contains a wide array of advanced sensitivity, uncertainty quantification, and optimization methods. These are now available in a “pluggable” way to any openMDAO based workflow.

Graf, Peter↗
DOE OSTI2013

Axions and saxions from the primordial supersymmetric plasma and extra radiation signatures

We calculate the rate for thermal production of axions and saxions via scattering of quarks, gluons, squarks, and gluinos in the primordial supersymmetric plasma. Systematic field theoretical methods such as hard thermal loop resummation are applied to obtain a finite result in a gauge-invariant way that is consistent to leading order in the strong gauge coupling. We calculate the thermally produced yield and the decoupling temperature for both axions and saxions. For the generic case in which saxion decays into axions are possible, the emitted axions can constitute extra radiation already prior to big bang nucleosynthesis and well thereafter. We update associated limits imposed by recent studies of the primordial helium-4 abundance and by precision cosmology of the cosmic microwave background and large scale structure. We show that the trend towards extra radiation seen in those studies can be explained by late decays of thermal saxions into axions and that upcoming Planck results will probe supersymmetric axion models with unprecedented sensitivity.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗