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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Tuning successive linear programming to solve AC optimal power flow problem for large networks

Successive linear programming (SLP) is a practical approach for solving large-scale nonlinear optimization problems. Alternating current optimal power flow (ACOPF) is no exception, particularly the large size of real-world networks. However, in order to achieve tractability, it is essential to tune the SLP algorithm presented in the literature. This paper presents a modified SLP algorithm to solve the ACOPF problem, specified by the U.S. Department of Energy’s (DOE) Grid Optimization (GO) Competition Challenge 1, within strict time limits. The algorithm first finds a near-optimal solution for the relaxed problem (i.e., Stage 1). Then, it finds a feasible solution in the proximity of the near-optimal solution (i.e., Stage 2 and Stage 3). The numerical experiments on test cases ranging from 500-bus to 30,000-bus systems show that the algorithm is tractable. Here the results show that our proposed algorithm is tractable and can solve more than 80% of test cases faster than the well-known Interior Point Method while significantly reduce the number of iterations required to solve ACOPF. The number of iterations is considered an important factor in the examination of tractability which can drastically reduce the computational time required within each iteration.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

Development and evaluation of an agar capture system (ACS) for high-throughput screening of insoluble particulate substrates with bacterial growth and enzyme activity assays

In this work, we describe a method for containing insoluble particulates for use as substrates in either bacterial growth or enzyme assays. This method was designed for high-throughput screening of environmental or engineered bacteria. Benchmarking this method with several model bacteria uncovered phenotypes not observable with the particulate substrates alone.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

AC-LGADs Fermilab front-end electronics characterization

Here, we characterized the front-end electronics used to process high-frequency signals from low-gain avalanche diodes (LGADs) at the Fermilab Test Beam Facility. LGADs are silicon detectors employed for charged particle tracking, offering exceptional spatial and temporal resolution. The purpose of this characterization was to understand how the time resolution is influenced by the front-end electronics. To achieve this, we developed a setup capable of generating input signals with varying amplitudes. The output results demonstrated that signal processing by the front-end electronics plays a crucial role in enhancing time resolution. We showed that the time resolution achieved by the FEE board is better than 2 p s at the 1 σ level.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Policies and Practices to Improve the Chemistry Graduate Student Experience: Implications of the ACS Survey of Graduate Students

STEM graduate education is vitally important in producing the talent needed to fuel our economy and provide solutions for the challenges we face in emerging diseases and climate change. Yet recent research indicates that women and students who identify as members of minority groups traditionally underrepresented in STEM face extraordinary challenges in their graduate careers. This commentary describes ways in which chemistry graduate education could become more supportive and inclusive through changes by graduate students, faculty, departments, funding agencies, and professional organizations. As a result the scientific workforce could utilize the full range of available talent and become more productive.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

ACS Spotlight: Bipolar Membranes for Electrochemical Energy Conversion, Chemical Manufacturing, and Separations

Sustainable energy conversion, chemical manufacturing, and separations are central to addressing the world’s energy and environmental challenges. Electrochemical platforms stand as a cornerstone in addressing these challenges because they are low exergy and can be powered on renewable electrons. In electrochemical systems, bipolar membranes (BPMs) are emerging as a unique class of ion exchange membranes poised to revolutionize various electrochemical processes via pH control of anode and cathode chambers and in situ pH adjustment. In this Spotlight Review, we provide a comprehensive review of electrochemical platforms utilizing BPMs for energy conversion (water electrolyzers for hydrogen production, fuel cells, and flow batteries), chemical manufacturing (electrolyzers that convert carbon dioxide into value-added chemicals and nitrate into ammonia), and separations. The motivation for using BPMs, as well as their performance and durability, in electrochemical platforms are disseminated. We also discuss current challenges that impede BPM electrochemical systems from competing with state-of-the-art electrochemical systems using monopolar ion-exchange membranes (e.g., anion/hydroxide exchange membranes and cation/proton exchange membranes). Here, the review also covers molecular modeling and continuum modeling efforts to understand the basic mechanisms that govern BPM performance.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2020

ACS Sustainable Chemistry & Engineering Virtual Special Issue on Recent Advances in Biomass Characterization and Modeling

Recognizing the importance of biomass characterization and modeling, a virtual special issue (VSI) entitled Recent Advances in Biomass Characterization and Modeling was organized to showcase the recent contributions to this emerging field. This VSI features contributions from leading scientists in the biorefinery field, intending to provide the readers with the latest advances in analytical methodology and modeling to characterize biomass feedstocks and biomass-derived products. Further, the VSI contains perspectives and research articles. Advanced analytical methods that measure the mechanical, chemical, physical, biological, and other properties of biomass and biomass pyrolysis products are described along with their application’s limitations in two perspectives. Biomass is a multicomponent/multiscale, complex, nonconducting, and highly heterogeneous material; thus, it could be problematic for many characterization techniques. Traditional biomass analysis tools that are slow, laborious, and generally require harsh reagents have been replaced or supplemented by simpler and more rapid chromatographic and spectroscopic approaches such as GC-MS, HPLC, FTIR, Raman, and NMR spectroscopies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗