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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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At least 1,009 records · Page 56
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

A tool and a methodology to use macros for abstracting variations in code for different computational demands

Scientific software used on high-performance computing platforms is in a phase of transformation because of the combined increase in the heterogeneity and complexity of models and hardware platforms. Having separate implementations for different platforms can easily lead to combinatorial explosions; therefore, the computational science community has been looking for mechanisms to express code through abstractions that can be specialized for different platforms. Most existing approaches use template meta-programming in C++, and are, therefore language specific. Here, we have developed a tool that uses customized expansion of macros to mimic some of C++ behavior in other languages. It enables unification of any code variants that may be necessary to run efficiently on different target architectures and different computational environments through use of macros with multiple alternative definitions and ability to arbitrate on definition selection for expansion. Combined with two other tools, a custom runtime, and a user specified recipe translator, our custom macroprocessor becomes a part of an overall performance portability solution that does not depend on any specific programming language. We also use macros as code-shorthand that lets code snippets become building blocks that allow variations in control flow to explore performance options. We demonstrate use of macros in Flash-X, a multiphysics multicomponent code with many Fortran legacy components derived from an earlier community code FLASH.

Heterogenous computing↗
DOE OSTI2018

Accelerating demand for residential solar photovoltaics: Can simple framing strategies increase consumer interest?

Household adoption of energy-efficient and renewable energy technologies has the potential to significantly reduce emissions from electricity generation. High upfront costs, however, are often a barrier to adoption, even when costs may be offset by future energy savings. Through a series of randomized experiments, we examine whether framing strategies grounded in behavioral economics and psychology can be used to increase the financial appeal of such products. Using mock ads for residential solar photovoltaics (PV), we test four frames: gain/loss framing, temporal framing, varied savings amounts, and simple vs. detailed savings calculations. Overall, we find that reframing the financial benefits of PV does not greatly influence the appeal of solar or the likelihood to respond to the mock ads. Instead, underlying consumer motivations and predispositions (i.e., perceived social support, consumer innovativeness, and personal pro-environmental norms) are the primary factors driving interest in adopting solar. Our findings suggest that tailoring messages to targeted consumer segments may be more effective than attempts to market the financial benefits of PV to broad audiences. Furthermore, the results also contribute to behavioral economics and psychology research by identifying contexts under which the gain/loss framing bias and the present/future framing bias may not apply.

14 SOLAR ENERGY↗
DOE OSTI2017

Cost and energy demand of producing nickel manganese cobalt cathode material for lithium ion batteries

The price of the cathode active materials in lithium ion batteries is a key cost driver and thus significantly impacts consumer adoption of devices that utilize large energy storage contents (e.g. electric vehicles). A process model has been developed and used to study the production process of a common lithium-ion cathode material, lithiated nickel manganese cobalt oxide, using the co-precipitation method. The process was simulated for a plant producing 6500 kg day –1 . The results indicate that the process will consume approximately 4 kWh kg NMC –1 of energy, 15 L kg NMC –1 of process water, and cost $23 to produce a kg of Li-NMC333. The calculations were extended to compare the production cost using two co-precipitation reactions (with Na 2 CO 3 and NaOH), and similar cathode active materials such as lithium manganese oxide and lithium nickel cobalt aluminum oxide. Finally, a combination of cost saving opportunities show the possibility to reduce the cost of the cathode material by 19%.

25 ENERGY STORAGE↗