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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 1,495 records · Page 83
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

The Need for and Path to Harmonized Life Cycle Assessment and Techno-Economic Assessment for Carbon Dioxide Capture and Utilization

The use of carbon dioxide as a feedstock for a broad range of products can help mitigate the effects of climate change through long-term removal of carbon or as part of a circular carbon economy. Research on capture and conversion technologies has intensified in recent years, and the interest in deploying these technologies is growing fast. However, sound understanding of the environmental and economic impacts of these technologies is required to drive fast deployment and avoid unintended consequences. Life cycle assessments (LCAs) and techno-economic assessments (TEAs) are useful tools to quantify environmental and economic metrics; however, these tools can be very flexible in how they are applied, with the potential to produce significantly different results depending on how the boundaries and assumptions are defined. Built on ISO standards for generic LCAs, several guidance documents have emerged recently from the Global CO 2 Initiative, the National Energy Technology Laboratory, and the National Renewable Energy Laboratory that further define assessment specifications for carbon capture and utilization. Overall agreement in the approaches is noted with differences largely based on the intended use cases. As a results, further guidance is needed for assessments of early-stage technologies, reporting details, and reporting for policymakers and nontechnical decision-makers.

09 BIOMASS FUELS↗
DOE OSTI2019

The Influence of Temperature on the Cyclic Properties of the Transversely Isotropic Nanocomposite System Under Kinematic Harmonic Loading

A micromechanical model is developed to determine the effective inelastic properties of nanocomposites under monoharmonic deformation by taking into account the detailed microstructural geometries and constitutive models of the constituents. By using the correspondence principle in viscoelasticity and the modified Mori–Tanaka method, the effects of interface between the inclusion and the matrix are taken into account. By applying the developed model, we perform the numerical analysis aimed at the determination of complex moduli for a polymeric nanocomposite reinforced with nanofibers composed from carbon nanotubes under the isothermal conditions. The dependences of complex moduli on temperature and the amplitude of strain intensity are analyzed. The composites reinforced with unidirectionally aligned nanofibers are considered. The accumulated results demonstrate a strong dependence of the storage and loss moduli on temperature within a broad temperature range. The storage and loss moduli are found to monotonically increase with the volume fraction of nanofibers. At the same time, they decrease as temperature increases. The obtained results show that the strength of material decreases as temperature increases in the elastic and inelastic regions and the inelastic behavior occurs for lower strain amplitude as temperature increases.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Extracting Charge and Mass Information from Highly Congested Mass Spectra Using Fourier-Domain Harmonics

Native mass spectra of large, polydisperse biomolecules with repeated subunits, such as lipoprotein Nanodiscs, can often be challenging to analyze by conventional methods. The presence of tens of closely spaced, overlapping peaks in these mass spectra can make charge state, total mass, or subunit mass determinations difficult to measure by traditional methods. Recently, we introduced a Fourier Transform-based algorithm that can be used to deconvolve highly congested mass spectra for polydisperse ion populations with repeated subunits and facilitate identification of the charge states, subunit mass, charge-state-specific, and total mass distributions present in the ion population. Here, we extend this method by investigating the advantages of using overtone peaks in the Fourier spectrum, particularly for mass spectra with low signal-to-noise and poor resolution. This method is illustrated for lipoprotein Nanodisc mass spectra acquired on three common platforms, including the first reported native mass spectrum of empty “large” Nanodiscs assembled with MSP1E3D1 and over 300 noncovalently associated lipids. It is shown that overtone peaks contain nearly identical stoichiometry and charge state information to fundamental peaks but can be significantly better resolved, resulting in more reliable reconstruction of charge-state-specific mass spectra and peak width characterization. We further demonstrate how these parameters can be used to improve results from Bayesian spectral fitting algorithms, such as UniDec. .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

A preconditioned dual–primal finite element tearing and interconnecting method for solving three-dimensional time-harmonic Maxwell's equations

A new preconditioned dual–primal nonoverlapping domain decomposition method is proposed for the finite element solution of three-dimensional large-scale electromagnetic problems. With the aid of two Lagrange multipliers, the new method converts the original volumetric problem to a surface problem by using a higher-order transmission condition at the subdomain interfaces to significantly improve the convergence of the iterative solution of the global interface equation. Similar to the previous version, a global coarse problem related to the degrees of freedom at the subdomain corner edges is formulated to propagate the residual error to the whole computational domain at each iteration, which further increases the rate of convergence. In addition, a fully algebraic preconditioner based on matrix splitting is constructed to make the proposed domain decomposition method even more robust and scalable. Perfectly matched layers (PMLs) are considered for the boundary truncation when solving open-region problems. The influence of the PML truncation on the convergence performance is investigated by examining the convergence of the transmission condition for an interface inside the PML. Numerical examples including wave propagation and antenna radiation problems truncated with PMLs are presented to demonstrate the validity and the capability of this method.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗