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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 55 records · Page 3

Community Energy by Design: A Simulation-Based Design Workflow Using Measured Data Clustering to Calibrate Urban Building Energy Models (UBEMs)

This paper presents a workflow that informs urban design decisions using measured data clustering to calibrate urban building energy models. The method's goal is to support urban design in terms of form, building systems configurations, as well as influencing user behavior aspects in the built environment through a systemic analysis of measured data to develop reliable future-case design scenario energy models. Detailed data on appliance-level electricity use are employed via data clustering to calibrate a urban building energy model for the Mueller community in Austin, TX, USA. The data were collected by the Pecan Street Institute for a year in 2014 from consumers in Austin and other surrounding cities. First, collected energy data were restructured and cleaned from corrupt and/or missing information. Second, in order to identify common energy use patterns, a model-based clustering algorithm for functional data was applied. Behavioral/usage profiles are determined through clustering and translated into usage schedules and behaviors. As a result, an urban building energy model built in the urban modeling interface (umi) was calibrated, with fully calibrated and semi-calibrated buildings, within a maximum calibration error margin of 14% for daily-scale averages. Finally, an illustration of calibrated-urban building energy model design case scenarios is presented, and implications on community energy potential effects are discussed.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Ligand-Size Related Dimensionality Control in Metal Halide Perovskites

Low-dimensional organic–inorganic hybrid perovskites have triggered many fundamental research studies due to their intrinsic tunable photovoltaic properties, technologically relevant stability, and promising efficiency. However, there is limited information on how ligand size influences inherent structural and electronic properties of perovskites. In order to gain deeper understanding of ligand-size related structural and film properties, we fabricated a series of (L) 2 (MA) n-1 PbnI 3n+1 materials by introducing organic spacer ligands of n-CH 3 CH 2 NH 3 (EA), n-CH 3 (CH 2 ) 2 NH 3 (PA), and n-CH 3 (CH 2 ) 3 NH 3 (BA) into the three-dimensional (3D) methylammonium (MA) lead iodide (MAPbI 3 ) system with the same inorganic layer thickness (average $\langle$n$\rangle$ = 4). Here, we demonstrate that the increased number of carbon atoms on ligands affects compatibility of ligands with the 3D [PbI 6 ] 4– framework, leading to different structural dimensionality and crystal orientation, largely explaining different electronic properties, crystal stability, and the consequent device performance of solar cells. This work provides key missing information on how ligand size influences structural dimensionality and desirable electronic properties for future stable and efficient solar cells.

36 MATERIALS SCIENCE↗

Russian anthropogenic black carbon: Emission reconstruction and Arctic black carbon simulation

Development of reliable source emission inventories is needed to advance the understanding of the origin of Arctic haze using chemical transport modeling. This paper develops a regional anthropogenic black carbon (BC) emission inventory for the Russian Federation, the largest country by land area in the Arctic Council. Activity data from combination of local Russia information and international resources, emission factors based on either Russian documents or adjusted values for local conditions, and other emission source data are used to approximate the BC emissions. Emissions are gridded at a resolution of 0.1° × 0.1° and developed into a monthly temporal profile. Total anthropogenic BC emission of Russia in 2010 is estimated to be around 224 Gg. Gas flaring, a commonly ignored black carbon source, contributes a significant fraction of 36.2% to Russia's total anthropogenic BC emissions. Other sectors, i.e., residential, transportation, industry, and power plants, contribute 25.0%, 20.3%, 13.1%, and 5.4%, respectively. Three major BC hot spot regions are identified: the European part of Russia, the southern central part of Russia where human population densities are relatively high, and the Urals Federal District where Russia's major oil and gas fields are located but with sparse human population. BC simulations are conducted using the hemispheric version of Community Multi-scale Air Quality Model with emission inputs from a global emission database EDGAR (Emissions Database for Global Atmospheric Research)-HTAPv2 (Hemispheric Transport of Air Pollution) and EDGAR-HTAPv2 with its Russian part replaced by the newly developed Russian BC emissions, respectively. The simulation using the new Russian BC emission inventory could improve 30–65% of absorption aerosol optical depth measured at the AERONET sites in Russia throughout the whole year as compared to that using the default HTAPv2 emissions. At the four ground monitoring sites (Zeppelin, Barrow, Alert, and Tiksi) in the Arctic Circle, surface BC simulations are improved the most during the Arctic haze periods (October–March). The poor performance of Arctic BC simulations in previous studies may be partly ascribed to the Russian BC emissions built on out-of-date and/or missing information, which could result in biases to both emission rates and the spatial distribution of emissions. Finally, this study highlights that the impact of Russian emissions on the Arctic haze has likely been underestimated, and its role in the Arctic climate system needs to be reassessed. The Russian black carbon emission source data generated in this study can be obtained via http://abci.ornl.gov/download.shtml or http://acs.engr.utk.edu/Data.php.

54 ENVIRONMENTAL SCIENCES↗

Schrödinger evolution of two-dimensional black holes

This paper systematically treats the evolving quantum state for two-dimensional black holes, with particular focus on the CGHS model, but also elucidating features generalizing to higher dimensions. This is done in Schrödinger picture(s), to exhibit the dynamic evolution of the state at intermediate times. After a review of classical solutions, also connecting to descriptions of higher-dimensional black holes, it overviews the canonical quantum treatment of the full evolution, including gravitational dynamics. Derived in an approximation to this, following conversion to “perturbation picture”, is the evolution of the quantum matter on the background geometry. Features of the evolving matter state are described, based on choice of a time slicing to put the evolution into ADM form. The choices of slicing as well as coordinates on the slices result in different quantum “pictures” for treating the evolution. If such a description is based on smooth trans-horizon slices, that avoids explicit reference to ultra-planckian modes familiar from traditional treatments, and exhibits the Hawking excitations as emerging from a “quantum atmosphere” with thickness comparable to the inverse temperature. Detailed study of the state exhibits the entanglement structure between Hawking quanta and the partner excitations inside the black hole, and the corresponding “missing information”. This explicit description also allows direct study of the evolution and features, e.g. as seen by infalling observers, of these partner excitations, helping to address various puzzles with them. Explicit treatment of the evolving state, and its extension to higher dimensions, provides further connections to information theory and a starting point for study of corrections that can unitarize evolution, arising from new quantum gravity effects — whether wormholes or something entirely different.

2D Gravity↗

Geophysical methods reveal the soil architecture and subsurface stratigraphic heterogeneities across land-lake interfaces along Lake Erie

Abstract Purpose The land-lake interface is a unique zone where terrestrial and aquatic ecosystems meet, forming part of the Earth’s most geochemically and biologically active zones. The unique characteristics of this interface are yet to be properly understood due to the inherently high spatiotemporal variability of subsurface properties, which are difficult to capture with the traditional soil sampling methods. Geophysical methods offer non-invasive techniques to capture variabilities in soil properties at a high resolution across various spatiotemporal scales. Methods We combined electromagnetic induction (EMI), electrical resistivity tomography (ERT), and ground penetrating radar (GPR) with data from soil cores and in situ sensors to investigate hydrostratigraphic heterogeneities across land-lake interfaces along the western basin of Lake Erie. Results EMI revealed high spatial heterogeneities in ECa distribution across the land-lake interfaces, with higher values in the wetland and transition zones compared to the upland zone. Soil ECa maps matched soil maps from a public database with the hydric soil units delineated as high conductivity zones (ECa > 40 mS/m). ERT and GPR showed vertical variation in soil properties with clear stratigraphic boundaries, and correlation of ERT profiles with lithologs from piezometers revealed the stratigraphic units of silt–clay and till sequence down to 3.5 m depth which are consistent with the surficial geology of the study area. Conclusions These results validate the use of multiple geophysical methods for extrapolating soil properties and mapping stratigraphic structures at land-lake interfaces, thereby providing the missing information required to improve the earth system model (ESM) of coastal interfaces.

54 ENVIRONMENTAL SCIENCES↗

Joint estimation of biogeochemical model parameters from multiple experiments: A bayesian approach applied to mercury methylation

Here, to characterize complex biogeochemical systems, results from multiple experiments, where each targets a specific subprocess, are commonly combined. The resulting datasets are interpreted through the calibration of biogeochemical models for process inference and predictions. Commonly used calibration approaches of fitting datasets from individual experiments to subprocess models one at a time is prone to missing information shared between datasets and incomplete uncertainty propagation. We propose a Bayesian joint-fitting scheme addressing the above-mentioned concerns by jointly fitting all the available datasets, thus calibrating the entire biogeochemical model in one go using Markov Chain Monte Carlo (MCMC). The identification of null spaces in the parameter distributions from MCMC guided the simplification of certain subprocess models. For example, fast kinetic sorption was replaced by equilibrium sorption, and Monod demethylation was replaced by first-order demethylation. Joint fitting of datasets resulted in complete uncertainty propagation with parameter estimates informed by all available data.

54 ENVIRONMENTAL SCIENCES↗

Outcomes of Proton Therapy for the Treatment of Uveal Metastases

Purpose/Objective(s): Radiation therapy can be used to treat uveal metastases with the goal of local control and improvement of quality of life. Proton therapy can be used to treat uveal tumors efficiently and with expectant minimization of normal tissue injury. Here, we report the use of proton beam therapy for the management of uveal metastases. Methods and Materials: A retrospective chart review was made of all patients with uveal metastases treated at our institution with proton therapy between June 2002 and June 2012. Patient and tumor characteristics, fractionation and dose schemes, local control, and toxicities are reported. Results: Ninety patients were identified. Of those, 13 were excluded because of missing information. We report on 77 patients with 99 affected eyes with available data. Patients were 68% female, and the most common primary tumor was breast carcinoma (49%). The median age at diagnosis of uveal metastasis was 57.9 years. Serous retinal detachment was seen in 38% of treated eyes. The median follow-up time was 7.7 months. The median dose delivered to either eye was 20 Gy(relative biological effectiveness [RBE]) in 2 fractions. Local control was 94%. The median survival after diagnosis of uveal metastases was 12.3 months (95% confidence interval, 7.7-16.8). Death in all cases was secondary to systemic disease. Radiation vasculopathy, measured decreased visual acuity, or both was observed in 50% of evaluable treated eyes. The actuarial rate of radiation vasculopathy, measured decreased visual acuity, or both was 46% at 6 months and 73% at 1 year. The 6 eyes with documented local failure were successfully salvaged with retreatment. Conclusions: Proton therapy is an effective and efficient means of treating uveal metastases. Acutely, the majority of patients experience minor adverse effects. For longer-term survivors, the risk of retinal injury with vision loss increases significantly over the first year.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Scientific data interpolation with low dimensional manifold model

Here, we propose to apply a low dimensional manifold model to scientific data interpolation from regular and irregular samplings with a significant amount of missing information. The low dimensionality of the patch manifold for general scientific data sets has been used as a regularizer in a variational formulation. The problem is solved via alternating minimization with respect to the manifold and the data set, and the Laplace–Beltrami operator in the Euler–Lagrange equation is discretized using the weighted graph Laplacian. Various scientific data sets from different fields of study are used to illustrate the performance of the proposed algorithm on data compression and interpolation from both regular and irregular samplings.

97 MATHEMATICS AND COMPUTING↗

Synthetic control over orientational degeneracy of spacer cations enhances solar cell efficiency in two-dimensional perovskites

Two-dimensional perovskites have emerged as more intrinsically stable materials for solar cells. Chemical tuning of spacer organic cations has attracted great interest due to their additional functionalities. However, how the chemical nature of the organic cations affects the properties of two-dimensional perovskites and devices is rarely reported. Here we demonstrate that the selection of spacer cations (i.e., selective fluorination of phenethylammonium) affects the film properties of two-dimensional perovskites, leading to different device performance of two-dimensional perovskite solar cells (average n = 4). Structural analysis reveals that different packing arrangements and orientational disorder of the spacer cations result in orientational degeneracy and different formation energies, largely explaining the difference in film properties. This work provides key missing information on how spacer cations exert influence on desirable electronic properties and device performance of two-dimensional perovskites via the weak and cooperative interactions of these cations in the crystal lattice.

14 SOLAR ENERGY↗

Unveiling the strong interaction among hadrons at the LHC

One of the key challenges for nuclear physics today is to understand from first principles the effective interaction between hadrons with different quark content. First successes have been achieved using techniques that solve the dynamics of quarks and gluons on discrete space-time lattices. Experimentally, the dynamics of the strong interaction have been studied by scattering hadrons off each other. Such scattering experiments are difficult or impossible for unstable hadrons and so high-quality measurements exist only for hadrons containing up and down quarks. Here we demonstrate that measuring correlations in the momentum space between hadron pairs produced in ultrarelativistic proton–proton collisions at the CERN Large Hadron Collider (LHC) provides a precise method with which to obtain the missing information on the interaction dynamics between any pair of unstable hadrons. Specifically, we discuss the case of the interaction of baryons containing strange quarks (hyperons). We demonstrate how, using precision measurements of proton–omega baryon correlations, the effect of the strong interaction for this hadron–hadron pair can be studied with precision similar to, and compared with, predictions from lattice calculations. The large number of hyperons identified in proton–proton collisions at the LHC, together with accurate modelling of the small (approximately one femtometre) inter-particle distance and exact predictions for the correlation functions, enables a detailed determination of the short-range part of the nucleon-hyperon interaction.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Ultrafast Photofragmentation of Ln(hfac)3 with a Proposed Mechanism for forming High Mass Fluorinated Products

Abstract The photo-induced dissociative-ionization of lanthanide complexes Ln(hfac) 3 (Ln = Pr, Er, Yb) is studied using intense ultrafast transform limited (TL) and linearly chirped laser pulses in a time-of-flight (TOF) mass spectrometry setup. Various fluorine and Ln-containing high-mass fragments were observed in this experiment, including the molecular parent ion, which have not been seen with previous studies relying on relatively long-duration laser pulses (i.e., ns or longer). These new high-mass observations provide important formerly missing information for deducing a set of photo-fragmentation mechanistic pathways for Ln(hfac) 3 . An overall ultrafast control mechanism is proposed by combining insights from earlier studies and the fragments observed in this research to result in three main distinct photo-fragmentation processes: (a) ligand-metal charge transfer, (b) CF 3 elimination, and (c) C-C bond rotation processes. We conclude that ultrafast dissociative-ionization could be a promising technique for generating high-mass fragments for potential use in material science applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Nanoscale defect evaluation framework combining real-time transmission electron microscopy and integrated machine learning-particle filter estimation

Observation of dynamic processes by transmission electron microscopy (TEM) is an attractive technique to experimentally analyze materials’ nanoscale phenomena and understand the microstructure-properties relationships in nanoscale. Even if spatial and temporal resolutions of real-time TEM increase significantly, it is still difficult to say that the researchers quantitatively evaluate the dynamic behavior of defects. Images in TEM video are a two-dimensional projection of three-dimensional space phenomena, thus missing information must be existed that makes image’s uniquely accurate interpretation challenging. Therefore, even though they are still a clustering high-dimensional data and can be compressed to two-dimensional, conventional statistical methods for analyzing images may not be powerful enough to track nanoscale behavior by removing various artifacts associated with experiment; and automated and unbiased processing tools for such big-data are becoming mission-critical to discover knowledge about unforeseen behavior. We have developed a method to quantitative image analysis framework to resolve these problems, in which machine learning and particle filter estimation are uniquely combined. The quantitative and automated measurement of the dislocation velocity in an Fe-31Mn-3Al-3Si autunitic steel subjected to the tensile deformation was performed to validate the framework, and an intermittent motion of the dislocations was quantitatively analyzed. The framework is successfully classifying, identifying and tracking nanoscale objects; these are not able to be accurately implemented by the conventional mean-path based analysis.

36 MATERIALS SCIENCE↗

Artifact reduction in industrial computed tomography via data fusion

As the most stressed part of a gas turbine the first row of turbine blades is not only a challenge for the materials used. Also the testing of these parts have to meet the highest standards. Computed tomography (CT) as the technique which could reveal the most details also provides the biggest challenges [1]: A full penetration of large sized turbine blades is often only possible at high X-ray voltages causing disproportional high costs. A reduction of the X-ray voltage is able to reduce these arising costs but yields non penetration artifacts in the reconstructed CT image. In most instances, these artifacts manifests itself as blurred and smeared regions at concave edges due to a reduced signal to noise ratio. In order to complement the missing information and to increase the overall image quality of our reconstruction, we use further imaging modalities such as a 3-D Scanner and ultrasonic imaging. A 3-D scanner is easy and cost effective to implement and is able to acquire all relevant data simultaneously with the CT projections. If, however, the interior structure is of supplemental interest, an ultrasonic imaging method is additionally used. We consider this data as a priori knowledge to employ them in an iterative reconstruction. To do so, standard iterative reconstruction methods are modified to incorporate the a priori data in a regularization approach in combination with minimizing the total variation of our image. Applying this procedure on turbine blades, we are able to reduce the apparent artifacts almost completely.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Quantum confinement in self-assembled two-dimensional nanoporous honeycomb networks at close-packed metal surfaces

Quantum confinement of a two-dimensional electron gas by supramolecular nanoporous networks is investigated using the boundary elements method based on Green’s functions for finite geometries and electron plane wave expansion for periodic systems. The “particle in a box” picture was analyzed for cases with selected symmetries that model previously reported architectures constructed from organic and metal-organic scattering centers confining surface state electrons of Ag(111) and Cu(111). First, by analyzing a series of cases with systematically defined parameters (scattering geometry, potentials, and effective broadening), we demonstrate how the scattering processes affect the properties of the confined electrons. For the features of the local density of states reported by scanning tunneling spectroscopy (STS), we disentangle the contributions of lifetime broadening and splitting of quantum well states due to coupling of neighboring quantum dots. For each system, we analyze the local electron density distribution and relate it to the corresponding band structure as calculated within the plane-wave expansion framework. Then, we address two experimental investigations, where in one case only STS data and in the other case mainly angle-resolved photoemission spectroscopy (ARPES) data were reported. In both cases, the experimental findings can be successfully simulated. Furthermore, the missing information can be complemented because our approach allows to correlate the information obtained by STS with that of ARPES. The combined analysis of several observations suggests that the scattering potentials created by the network originate primarily from the adsorbate-induced changes of the local surface dipole barrier.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

Imaging outside the box: Resolution enhancement in X-ray coherent diffraction imaging by extrapolation of diffraction patterns

Coherent diffraction imaging is a high-resolution imaging technique whose potential can be greatly enhanced by applying the extrapolation method presented here. We demonstrate the enhancement in resolution of a non-periodical object reconstructed from an experimental X-ray diffraction record which contains about 10% missing information, including the pixels in the center of the diffraction pattern. A diffraction pattern is extrapolated beyond the detector area and as a result, the object is reconstructed at an enhanced resolution and better agreement with experimental amplitudes is achieved. The optimal parameters for the iterative routine and the limits of the extrapolation procedure are discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

TreeSAPP: the Tree-based Sensitive and Accurate Phylogenetic Profiler

Microbial communities drive matter and energy transformations integral to global biogeochemical cycles, yet many taxonomic groups facilitating these processes remain poorly represented in biological sequence databases. Due to this missing information, taxonomic assignment of sequences from environmental genomes remains inaccurate. We present the Tree-based Sensitive and Accurate Phylogenetic Profiler (TreeSAPP) software for functionally and taxonomically classifying genes, reactions and pathways from genomes of cultivated and uncultivated microorganisms using reference packages representing coding sequences mediating multiple globally relevant biogeochemical cycles. TreeSAPP uses linear regression of evolutionary distance on taxonomic rank to improve classifications, assigning both closely related and divergent query sequences at the appropriate taxonomic rank. TreeSAPP is able to provide quantitative functional and taxonomic classifications for both assembled and unassembled sequences and files supporting interactive tree of life visualizations.

54 ENVIRONMENTAL SCIENCES↗

Experimental evidence for nonspherical magnetic form factor in Ru 3 +

The Mott insulator ..alpha..-RuCl3 has generated great interest in the community due to its possible field-induced Kitaev quantum spin liquid state. Despite enormous effort spent trying to obtain the form of the low-energy Hamiltonian, there is currently no agreed upon set of parameters which is able to explain all of the data. A key piece of missing information lies in the determination of the magnetic form factor of Ru3+, particularly for a true quantitative treatment of inelastic neutron scattering data. Here we present the experimentally derived magnetic form factor of Ru3+ in the low spin 4d5 state using polarized neutron diffraction within the paramagnetic regime on high-quality single crystals of ..alpha..-RuCl3. We observe strong evidence of an anisotropic form factor, expected of the spin-orbit coupled jeff=12 ground state. We model the static magnetization density in increasing complexity from simple isotropic cases, to a multipolar expansion, and, finally, ab initio calculations of the generalized jeff=12 ground state. Comparison of both single ion models and inclusion of Cl- anions support the presence of hybridization of Ru3+ with the surrounding Cl- ligands.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

A comparison of deep-learning-based inpainting techniques for experimental X-ray scattering

The implementation is proposed of image inpainting techniques for the reconstruction of gaps in experimental X-ray scattering data. The proposed methods use deep learning neural network architectures, such as convolutional autoencoders, tunable U-Nets, partial convolution neural networks and mixed-scale dense networks, to reconstruct the missing information in experimental scattering images. In particular, the recovered pixel intensities are evaluated against their corresponding ground-truth values using the mean absolute error and the correlation coefficient metrics. The results demonstrate that the proposed methods achieve better performance than traditional inpainting algorithms such as biharmonic functions. Overall, tunable U-Net and mixed-scale dense network architectures achieved the best reconstruction performance among all the tested algorithms, with correlation coefficient scores greater than 0.9980.

97 MATHEMATICS AND COMPUTING↗