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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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PyDSS is a high level Python interface for OpenDSS and provides the following functionalities: 1] Object oriented programming, 2] Dynamic visualization, 3] Custom controls, 4] Simulation parallelization, 5] Exporting results, 6] Improved error logging, and 7] Communication interface. Documentation on installation, setup and examples can be found here https://nrel.github.io/PyDSS/index.html
Buildings’ thermal energy systems for providing space heating/cooling consume a considerable amount of electricity nationwide. Integrating thermal energy storage with buildings’ thermal systems has the potential to shave the peak electric demand and to overcome the mismatch between the intermittent renewable power and the fluctuating daily demand for electricity. A novel dual-purpose underground thermal battery (DPUTB) has been developed to provide diurnal thermal energy storage in conjunction with a dual-source heat pump (DSHP)system. A two-dimensional numerical model is developed to simulate the transient performance of the DPUTB. This model has similar accuracy as a detailed three-dimensional model developed with commercial heat transfer and fluid dynamics simulation program but with 1000 times faster computational speed. A parametric study is performed to identify a design of the DPUTB that can provide 14 kWh thermal storage capacity for each charging and discharging cycle. A system simulation has been developed to assess the performance of the designed DPUTB when it is integrated with a DSHP for conditioning a typical residential building in summer and winter. Simulation results indicate that the DPUTB can meet all the design requirements in both summer and winter with the simple rule-based control strategy and the overall integrated DPUTB and DSHP system can shift the electric load for meeting the thermal demand from the peak hours to off-peak hours during a day, which would result in considerable energy cost savings if a Time of Use electricity tariff is applicable.
Recent episodes of natural disasters have challenged the resilience of power grids. Adequate distribution grid planning that properly captures the risk aversion of the utility system planner is a key factor to increase the flexibility of distribution networks to circumvent these events. In this paper, we propose a methodology to determine the optimal portfolio of investments in lines and storage devices in order to minimize a convex combination between expected value and CVaR of operational costs, including energy not served, while taking into account the multistage nature of the energy storage management within this context. While the expected value of energy not served has been traditionally employed to tackle routine failures, we also minimize the CVaR of energy not served to address high-impact, low-probability (HILP) events. We illustrate the performance of the proposed methodology with a 54-Bus system test case.
The Saturn S-II stage and the Apollo spacecraft will include in their design and construction various pressurized tubing systems that will encounter service temperatures of 280° F to -423° F. Design engineering and reliability requirements and weight restrict ions have dictated new concepts to assure leak-tight joints for rocket engine fuel lines, pressurization systems, utility systems, and hydraulic systems. An investigation was initiated at North American Aviation, Inc., Space and Information Systems Division, utilizing the in-place automatically controlled miniaturized fusion-welding equipment originally developed by the Los Angeles Division of NAA and modified to meet the needs of Apollo and Saturn welded tubular systems. The objective was to make circumferential flanged weld joints in any position in 304L stainless for Saturn S-II and sleeve-type joints in 304L for Apollo. Inconel X, commercially pure titanium, 5052-0 aluminum, and 6061 T6 aluminum were also tested experimentally. Extensive environmental, static, and dynamic testing programs were conducted to determine the as-welded mechanical properties, design allowables, and reliability for the tube joints. This paper discusses both the experimental and production phases. Subsequently, the new tube welding process was approved and incorporated into manufacturing fabrication methods for tube joining.
Denumerable state Markovian decision processes - average cost criterion
The dynamic environment of the Ranger spacecraft (I through IX)during the launch portion of flight is defined in this Report. Flight data from each of nine spacecraft launches have been reviewed and are included. The environments receiving emphasis herein include liftoff acoustics, liftoff and transonic vibration, and the transient vibrations of the various pyrotechnic and staging events in the launch sequence. The systems for data acquisition and analysis are briefly described. In addition, post-flight comparison of flight data and ground test specification levels is made, and the dynamic test program is briefly discussed.
Three models of constrained preview control with successive target values of nonuniform importance
Optimal control of dynamic systems with minimax type performance index, discussing application of proposed method of solution
Liapunov method synthesis of time variable nonlinear multivariable systems, deriving simplified control law for tracking of linear noninteracting model
NASA Biosatellite Program exploring dynamic space flight effects on terrestrial organisms and Earth diurnal rotation effect on biological rhythm
Nonlinear feedback solution for minimum-time injection into circular orbit with constant thrust acceleration magnitude
Seismological equipment for space research applied to earthquake-resistant structural design
Optimal control of dynamic systems with minimax type performance index, discussing application of proposed method of solution
Multistage linear dynamic systems with sequentially correlated noise, evaluating filtering, prediction and smoothing procedures
Users manual on static and dynamic computer programs on linear elastic thin shell theory - Apollo command module water impact
Full scale dynamic test programs of large booster vehicles - monograph
NASA computer program for dynamic structural analysis in stress and thermal deformation problems
Satellite altitude determination uncertainties are discussed from the standpoint of the GEOS-C satellite. GEOS-C will be tracked by a number of the conventional satellite tracking systems, as well as by two advanced systems; a satellite-to-satellite tracking system and lasers capable of decimeter accuracies which are being developed in connection with the Goddard Earth and Ocean Dynamics Applications program. The discussion is organized in terms of a specific type of GEOS-C orbit which would satisfy a number of scientific objectives including the study of the gravitational field by means of both the altimeter and the satellite-to-satellite tracking system, studies of tides, and the Gulf Stream meanders.