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All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

The optical and near-infrared colors of galaxies, 1: The photometric data

We present optical and near-infrared photometry and spectroscopic redshifts of a well defined sample of 171 field galaxies selected from three high galactic latitude fields. This data set forms the basis for subsequent studies to characterize the trends, dispersion, and evolution of rest-frame colors and image structure. A subset of 143 galaxies constitutes a magnitude-limited sample to B approx. 19.9-20.75 (depending on field), with a median redshift of 0.14, and a maximum redshift of 0.54. This subset is statistically representative in its sampling of the apparent color distribution of galaxies. Thirty six galaxies were selected to have the reddest red-optical colors in two redshift intervals between 0.2 less than z less than 0.3. Photometric passbands are similar to U, B, V, I, and K, and sample galaxy spectral energy distributions between 0.37 and 2.2 micrometers in the observed frame, or down to 0.26 micrometers in the rest frame for the most distant galaxies. B and K images of the entire sample are assembled to form the first optical and near-infrared atlas of a statistically-representative sample of field galaxies. We discuss techniques for faint field-galaxy photometry, including a working definition of a total magnitude, and a method for matching magnitudes in different passbands and different seeing conditions to ensure reliable, integrated colors. Photographic saturation, which substantially affects the brightest 12% of our sample in the optical bands, is corrected with a model employing measured plate-density distributions for each galaxy, calibrated via similar measurements for stars as a function of known saturation level. Both the relative and absolute calibration of our photometry are demonstrated.

Bershady, Matthew A.↗
NASA NTRS1972

A modular Space Station/Base electrical power system - Requirements and design study.

The requirements and procedures necessary for definition and specification of an electrical power system (EPS) for the future space station are discussed herein. The considered space station EPS consists of a replaceable main power module with self-contained auxiliary power, guidance, control, and communication subsystems. This independent power source may 'plug into' a space station module which has its own electrical distribution, control, power conditioning, and auxiliary power subsystems. Integration problems are discussed, and a transmission system selected with local floor-by-floor power conditioning and distribution in the station module. This technique eliminates the need for an immediate long range decision on the ultimate space base power sources by providing capability for almost any currently considered option.

Eliason, J. T.↗
DOE OSTI2014

Synergistic Catalysis between Pd and Fe in Gas Phase Hydrodeoxygenation of m-Cresol

In this work, a series of Pd/Fe2O3 catalysts were synthesized, characterized, and evaluated for the hydrodeoxygenation (HDO) of m-cresol. It was found that the addition of Pd remarkably promotes the catalytic activity of Fe while the product distributions resemble that of monometallic Fe catalyst, showing high selectivity towards the production of toluene (C-O cleavage without saturation of aromatic ring and C-C cleavage). Reduced catalysts featured with Pd patches on the top of reduced Fe nanoparticle surface, and the interaction between Pd and Fe was further confirmed using X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM) and X-ray absorption near edge fine structure (XANES). A possible mechanism, including Pd assisted H2 dissociation and Pd facilitated stabilization of metallic Fe surface as well as Pd enhanced product desorption, is proposed to be responsible for the high activity and HDO selectivity in Pd-Fe catalysts. The synergic catalysis derived from Pd-Fe interaction found in this work was proved to be applicable to other precious metal promoted Fe catalysts, providing a promising strategy for future design of highly active and selective HDO catalysts.

09 BIOMASS FUELS↗
DOE OSTI2017

Environmental Selection, Dispersal, and Organism Interactions Shape Community Assembly in High-Throughput Enrichment Culturing

A central goal of microbial ecology is to identify and quantify the forces that lead to observed population distributions and dynamics. However, these forces, which include environmental selection, dispersal, and organism interactions, are often difficult to assess in natural environments. Here in this paper, we present a method that links microbial community structures with selective and stochastic forces through highly replicated subsampling and enrichment of a single environmental inoculum. Specifically, groundwater from a well-studied natural aquifer was serially diluted and inoculated into nearly 1,000 aerobic and anaerobic nitrate-reducing cultures, and the final community structures were evaluated with 16S rRNA gene amplicon sequencing. We analyzed the frequency and abundance of individual operational taxonomic units (OTUs) to understand how probabilistic immigration, relative fitness differences, environmental factors, and organismal interactions contributed to divergent distributions of community structures. We further used a most probable number (MPN) method to estimate the natural condition-dependent cultivable abundance of each of the nearly 400 OTU cultivated in our study and infer the relative fitness of each. Additionally, we infer condition-specific organism interactions and discuss how this high-replicate culturing approach is essential in dissecting the interplay between overlapping ecological forces and taxon-specific attributes that underpin microbial community assembly. IMPORTANCE Through highly replicated culturing, in which inocula are subsampled from a single environmental sample, we empirically determine how selective forces, interspecific interactions, relative fitness, and probabilistic dispersal shape bacterial communities. These methods offer a novel approach to untangle not only interspecific interactions but also taxon-specific fitness differences that manifest across different cultivation conditions and lead to the selection and enrichment of specific organisms. Additionally, we provide a method for estimating the number of cultivable units of each OTU in the original sample through the MPN approach.

16S RNA↗
DOE OSTI2016

Drive Electric Vermont Case Study

Currently in the United States, the heavy majority of plug-in electric vehicle (PEV) sales have been in highly conducive, selected, metropolitan areas; opposed to more broad distribution across the country. The U.S. Department of Energy’s EV Everywhere Grand Challenge is looking carefully at the barriers and opportunities that exist to enable small and midsize communities to partake in the PEV market and benefit from the economic and environmental advantages of PEVs. In order to gain insight into these challenges and barriers, DOE selected a success story (i.e., Drive Electric Vermont) as the subject of this case study, as the state of Vermont is tied with Detroit, Michigan in having the highest percentage of 2014 (most recent complete data) PEV registrations for cold weather U.S. cities and has seen more than a sixfold increase in charging stations over the last three years. The overall objective of this case study was to use the lessons learned from Drive Electric Vermont to determine what activities are most effective at encouraging acquisitions of PEVs and deployment of charging infrastructure in small to midsize communities, prioritizing and sequencing their implementation, identifying robust means for extrapolation, and applying this understanding to other small to midsize communities across the nation. The Drive Electric Vermont Program was formed in 2012 with a goal of increasing the use of electrified transportation in Vermont through policy development, education and outreach, and infrastructure development. The Drive Electric Vermont Program can be broadly broken into four components: (1) strategic planning/leadership, (2) stakeholder/partnership development, (3) education and outreach, and (4) incentives. The early phases of the program focused heavily on strategic planning, and stakeholder and partnership development, followed by a transition to education and outreach activities, charging infrastructure development, and grant and incentive programs that support charging infrastructure deployment and PEV purchases. Future plans include an additional round of consumer/dealer PEV incentives, continuation of the marketing campaign, and utilization of consumer surveys to develop new campaign themes and to optimize information distribution channels. In Vermont, the number of PEVs grew from 88 in July 2012 to 1,113 in January 2016, with a high percentage of the PEVs being plug-in hybrids (i.e., 865) versus all electric vehicles (i.e., 248). The most popular PEVs are Toyota’s Prius Plug-in and Ford’s C-Max Energi, which make up a combined 48% of the total PEV ownership in the state. The PEVs are predominantly clustered in four counties: Lamoille, Caledonia, Washington, and Chittenden. There is no evident correlation between community size and PEV penetration; however, over 70% of PEV owners are in communities of 1,000 to 10,000 people. On the other hand, there is a close correlation between where PEVs are registered and where they publically charge. The number of PEV charging stations in Vermont grew from 17 in January 2013 to 111 in January 2016, at a variety of charging venues, including retail, parking (short term and long term), workplace, dealerships, hotels, education, leisure, and hospitals. The vast majority of the charging venues contain Level 2 electric vehicle supply equipment (EVSE) solely or combined with Level 1 EVSE or direct current fast charging. The average power transferred per charging event for communities across Vermont ranged from 4.8 to 13.8 kWh for direct current fast charging and 1.0 to 11.9 kWh for and Level 2 EVSE. Over half the charging locations offer free charging. For those that do require payment, different pricing models are employed, including monthly memberships, hourly payment (where there is often a higher fee for the first hour followed by a lower hourly fee for the remaining hours), and energy use based on kWh drawn from the EVSE. There is no correlation between pricing models and community size and region, the strongest correlation is by network provider. Charging events across Vermont generally correlate with east-west bands of chargers (Figure ES-1) running from Burlington to Montpelier and in the area of Rutland.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2014

SU-F-19A-11: Retrospective Evaluation of Thermal Coverage by Thermobrachytherapy Seed Arrangements of Clinical LDR Prostate Implants

Purpose: The superiority of a properly-administered combination of radiation therapy and hyperthermia over radiation alone in treatment of human cancers has been demonstrated in multiple studies examining radiobiology, local control, and survival. Unfortunately, hyperthermia is not yet a common modality in oncology practice, due in part to the technical difficulty of heating a deep-seated target volume to sufficient temperature. To address this problem, our group has invented a thermobrachytherapy (TB) seed based on a commonly-used low dose-rate permanent brachytherapy seed for implant in solid tumors. Instead of the tungsten radiographic marker of the standard seed, the TB seed contains one of a self-regulating ferromagnetic alloy. Placement of a patient implanted with such seeds in an oscillating magnetic field generates heat via induction of eddy currents. We present the results of studies of the capability of clinically-realistic TB seed arrangements to adequately heat defined target volumes. Methods: Seed distributions for several past LDR prostate permanent implant brachytherapy patients were reproduced in the finite element analysis software package COMSOL Multiphysics 4.4, with the difference that TB seeds were modelled, rather than the radiation-only seeds actually used for their treatments. The implant geometries were mainly of the modified peripheral loading type; a range of prostatic volumes and blood perfusion rates likely to be seen in a clinical setting were examined. Results: According to the simulations, when distributed to optimize radiation dose, TB seeds also produce sufficient heat to provide thermal coverage of the target given proper selection of the magnetic field strength. However, the thermal distributions may be improved by additional use of hyperthermia-only seeds. Conclusion: A dual-modality seed intended as an alternative to and using the same implantation apparatus and technique as the standard LDR permanent implant seed has been successfully evaluated for its ability to provide sufficient hyperthermia in clinically-realistic implants. This work was partially supported by the National Institutes of Health (NIH) STTR Grant No. R41 CA153631-01A1.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

A Selective Overview and Comparison of Robust Mixture Regression Estimators

Summary Mixture regression models have been widely used in business, marketing and social sciences to model mixed regression relationships arising from a clustered and thus heterogeneous population. The unknown mixture regression parameters are usually estimated by maximum likelihood estimators using the expectation–maximisation algorithm based on the normality assumption of component error density. However, it is well known that the normality‐based maximum likelihood estimation is very sensitive to outliers or heavy‐tailed error distributions. This paper aims to give a selective overview of the recently proposed robust mixture regression methods and compare their performance using simulation studies.

Yu, Chun↗
NASA NTRS2009

Efficient File Sharing by Multicast - P2P Protocol Using Network Coding and Rank Based Peer Selection

In this work, we consider information dissemination and sharing in a distributed peer-to-peer (P2P highly dynamic communication network. In particular, we explore a network coding technique for transmission and a rank based peer selection method for network formation. The combined approach has been shown to improve information sharing and delivery to all users when considering the challenges imposed by the space network environments.

military↗
NASA NTRS1990

A solution adaptive grid procedure for an upwind parabolized flow solver

A solution adaptive grid procedure based on an error equi-distribution scheme is developed and applied to a Parabolized Navier-Stokes solver. An improved method for selecting weighting functions is introduced which involves normalizing a combination of flowfield gradients and curvature of a number of dependent variables and then selecting the largest at each point. The scheme re-distributes grid points line-by-line, with grid point motion controlled by forces analogous to tensional and torsional spring forces with the spring constants set equal to the weighting functions. Torsional terms are functions of the grid point positions along neighboring grid lines and provide grid smoothness and stability. A grid-fitting scheme is introduced for external flows in which the number of grid points in the freestream are reduced to a minimum. Results for several problems are presented to demonstrate the improvements obtainable with the solution adaptive grid procedure.

Harvey, Albert D.↗
DOE OSTI2021

Energy and power quality measurement for electrical distribution in AC and DC microgrid buildings

Today's selection of DC microgrid buildings features a diverse set of electrical topologies and turnkey solutions, each with specific design trade-offs and optimizations. Designers desperately need standardized metrics and procedures for measurement and verification (M&V) to analyze and compare the advantages of each DC solution to traditional AC building networks. This work develops M&V procedures for quantifying and comparing the energy efficiency and power quality in buildings. To calculate full-building efficiency, this work introduces the measurement-informed modeling method, a procedure that develops and refines a building's energy model with metered data. To quantify power quality, this work defines a new voltage quality index that applies to both AC and DC buildings. This article describes the equipment, instrumentation, and operation necessary to calculate the efficiency and power quality. It then demonstrates these methods with a set of field tests. We report these M&V procedures can ultimately be used to compare and improve the efficiency and power quality of various DC topologies.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Understanding hydrogen pressure control of furfural hydrogenation selectivity on a Pd(1 1 1) model catalyst

We investigate the postulate that hydrogen pressure influences the furfural hydrogenation selectivity on palladium to form decarbonylation products at low hydrogen pressures, but 2-methyl furan at higher pressures. This change is caused by co-adsorbed hydrogen changing the orientation of adsorbed furfural; low hydrogen coverages favor flat-lying furfural, higher coverages form tilted species. This was tested for hydrogenation of furfural on a Pd(1 1 1) single crystal. The product distribution agreed with the postulate, with 100% selectivity to furan and tetrahydrofuran for low hydrogen pressures, with 2-methyl furan increasing with hydrogen pressure. The origin of the effect is explored using reflection–absorption infrared spectroscopy. This showed that co-adsorbed hydrogen influenced the orientation in a way predicted by theory. It was also found that other co-adsorbates displayed similar effects implying that a range of molecules in the reaction mixture could have significant effects on the furfural selectivity.

09 BIOMASS FUELS↗
DOE OSTI2021

Validation Metrics for Fixed Effects and Mixed-Effects Calibration

The modern scientific process often involves the development of a predictive computational model. To improve its accuracy, a computational model can be calibrated to a set of experimental data. A variety of validation metrics can be used to quantify this process. Some of these metrics have direct physical interpretations and a history of use, while others, especially those for probabilistic data, are more difficult to interpret. In this work, a variety of validation metrics are used to quantify the accuracy of different calibration methods. Frequentist and Bayesian perspectives are used with both fixed effects and mixed-effects statistical models. Through a quantitative comparison of the resulting distributions, the most accurate calibration method can be selected. Two examples are included which compare the results of various validation metrics for different calibration methods. It is quantitatively shown that, in the presence of significant laboratory biases, a fixed effects calibration is significantly less accurate than a mixed-effects calibration. This is because the mixed-effects statistical model better characterizes the underlying parameter distributions than the fixed effects model. The results suggest that validation metrics can be used to select the most accurate calibration model for a particular empirical model with corresponding experimental data.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2023

Evaluation of thermostat location for multizone commercial building performance

In multi-zone buildings, it is often found that a single shared thermostat controls more than one conditioned zones. Although these shared zones are supposed to have similar thermal needs (e.g., cooling and heating load), in reality, they are not mainly due to different orientations, sizes of windows, occupancy, space types, etc. This can cause unnecessary energy waste or thermal discomfort for the occupants. How to quantify this impact in multizone buildings remains a research gap. Therefore, this study aims to evaluate the impact of different sensor (i.e., thermostat) locations for multizone commercial buildings through a comprehensive modeling study. Here, two different scenarios for the sensor locations were selected to evaluate the impact in terms of energy and thermal comfort. The scenario (1) is that one to five sensors distributed among the five zones, but the sensor readings from selected zones will be used for no-sensor zones, which is no-mean sensor scenario. The scenario (2) is that one to five sensors distributed among the five zones, but the average temperature from the shared zones will be used for each of the shared zones, which is a mean sensor scenario. The uncertainty analysis was performed for different sensor location scenarios.(a)The major findings from an energy perspective, for scenario (1), the differences of cooling energy go as high as 17% more or 12% less, compared with the baseline. For heating energy consumption, the discrepancies go as high as 51% more or 52% less, compared with baseline. For site energy consumption, the discrepancies go as high as 3.2% more or 3.2% less, compared with baseline. For fan energy consumption, the discrepancies go as high as 3.2% more or as low as 1.0% less, compared with baseline. For scenario (2), the discrepancies of cooling energy go as high as 3% more, or 0.5% less, compared with the baseline. For heating energy consumption, the discrepancies, are go as high as 10.1% more or as low as 3.0% less, compared with baseline. For site energy consumption, the discrepancies go as high as 1.3% more or 0.3% less, compared with baseline. For fan energy consumption, the discrepancies go as high as 3.1% more or as low as 1.0% less, compared with baseline.(b) In terms of the indoor thermal comfort, for the no-mean-sensor scenarios, the discrepancies of unmet hours for cooling mode can be as high as 1,200 h, compared with the baseline. The discrepancies of unmet hours for heating mode can be as high as 740 h, compared with the baseline. For the mean-sensor scenarios, the discrepancies of unmet hours for cooling mode can be as high as 750 h, compared with the baseline. The discrepancies of unmet hours for heating mode can be as high as 50 h, compared with the baseline.

42 ENGINEERING↗
DOE OSTI2020

Carbidic Mo is the sole kinetically-relevant active site for catalytic methane dehydroaromatization on Mo/H-ZSM-5

Systematic variation of Mo/Al = {0.10, 0.25, 0.35} in Mo/H-ZSM-5 catalysts effects ~20× change of Mo-to-H + ratio during methane dehydroaromatization (DHA) reactions at steady state and on deactivating catalysts. Mo and Brønsted-acid site count, respectively enumerated by ethane hydrogenolysis probe reaction and dimethyl ether chemical titration, evolve disparately during DHA catalysis, indicating the two sites reduce in number by distinct mechanisms. Here, the deactivation of Mo/H-ZSM-5 catalytic activity is uniquely attributed to the loss of active, or accessible, Mo sites, evinced by (i) the non-selective nature of deactivation (i.e. that deactivation occurs without modification of residual active sites), (ii) invariance in product distribution from Mo/H + = 0.10–2.1, and (iii) linear correspondence between Mo-catalyzed ethane hydrogenolysis rate and active site count during DHA on deactivating samples. DHA forward rate – the intrinsic kinetic descriptor of catalyst activity – normalizes by Mo content at steady state and on deactivating catalysts with Mo/Al = 0.10–0.35 for Mo-based contact times in the range τ Mo = 0.79–44 mol Mo s mol –1 C , unequivocally establishing Mo aggregates as the sole kinetically-relevant active site on Mo/H-ZSM-5. Brønsted-acid site content over a ~40× range in τ H+ = 1.4–54 mol H+ s mol –1 C has no discernable correlation with or effect on DHA rate, methane conversion, or product distribution – demonstrating H + does not catalyze any rate- or selectivity-determining steps in the benzene formation pathway and suggesting that the benefits of zeolitic acid sites are only to disperse Mo during catalyst synthesis and, conceivably, to catalyze equilibrated reaction steps.

02 PETROLEUM↗
DOE OSTI2019

2,2′-Dipyridylamine as Heterogeneous Organic Molecular Electrocatalyst for Two-Electron Oxygen Reduction Reaction in Acid Media

Continuous production of hydrogen peroxide (H 2 O 2 ) through the two-electron oxygen reduction reaction (2e-ORR) in distributed electrochemical cells offers important advantages for point-of-use water treatment and pulp bleaching over the complex industrial anthraquinone process. A low-cost, heterogeneous 2e-ORR electrocatalyst with high activity and selectivity is key to meeting the future needs for distributed production of H 2 O 2 with large capacity. Herein, we demonstrate high activity and selectivity of a heterogeneous organic molecular electrocatalyst, 2,2’-dipyridylamine, with an H 2 O 2 yield of ca. 80%, and an onset potential of ca. 0.60 V vs. RHE in acidic aqueous electrolyte. We show that this acid-compatible, inexpensive, small organic molecule can catalyze 2e-ORR as efficiently as the state-of-the-art catalysts based on mercury-precious metal alloys. We propose different mechanisms of dioxygen electroreduction based on density functional theory calculations, which correlate activity with calculated standard reduction potential of reaction intermediates.

2↗
DOE OSTI2018

Selection Signatures Underlying Dramatic Male Inflorescence Transformation During Modern Hybrid Maize Breeding

Inflorescence capacity plays a crucial role in reproductive fitness in plants, and in production of hybrid crops. Maize is a monoecious species bearing separate male and female flowers (tassel and ear, respectively). The switch from open-pollinated populations of maize to hybrid-based breeding schemes in the early 20th century was accompanied by a dramatic reduction in tassel size, and the trend has continued with modern breeding over the recent decades. The goal of this study was to identify selection signatures in genes that may underlie this dramatic transformation. Using a population of 942 diverse inbred maize accessions and a nested association mapping population comprising three 200-line biparental populations, we measured 15 tassel morphological characteristics by manual and image-based methods. Genome-wide association studies identified 242 single nucleotide polymorphisms significantly associated with measured traits. We compared 41 unselected lines from the Iowa Stiff Stalk Synthetic (BSSS) population to 21 highly selected lines developed by modern commercial breeding programs, and found that tassel size and weight were reduced significantly. We assayed genetic differences between the two groups using three selection statistics: cross population extended haplotype homozogysity, cross-population composite likelihood ratio, and fixation index. All three statistics show evidence of selection at genomic regions associated with tassel morphology relative to genome-wide null distributions. These results support the tremendous effect, both phenotypic and genotypic, that selection has had on maize male inflorescence morphology.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Supplemental Information for New York State Standardized Interconnection Requirements

This document is intended to aid in the understanding and application of the New York State Standardized Interconnection Requirements (SIR) and Application Process for New Distributed Generators 5 MW or Less Connected in Parallel with Utility Distribution Systems, and it aims to provide supplemental information and discussion on selected topics relevant to the SIR. This guide focuses on technical issues that have to date resulted in the majority of utility findings within the context of interconnecting photovoltaic (PV) inverters. This guide provides background on the overall issue and related mitigation measures for selected topics, including substation backfeeding, anti-islanding and considerations for monitoring and controlling distributed energy resources (DER).

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2021

Analysis of Approximations in Modeling of BWR Bundle Void Distributions

In boiling water reactors, complex heterogeneous bundle designs, control blades adjacent to the corner of bundles, and the presence of boiling can lead to complex internal void distributions. A few approximations exist to model these void distributions. They could be modeled using a 1D axial solver in which each axial node is assumed to be at an average void, or each pin cell could be modeled with its own void concentration. In the latter case, the void could be discretized in pin-centered or coolant-centered channels. The goal of this project was to quantify the effect of using the different approximations for modeling internal void distributions on neutronics calculations. Using 3D void distributions calculated with CTF, Monte Carlo Neutral Particle (MCNP) transport code models were created for GE-9 and GE-14 lattices. For each model, the internal void distribution from CTF at a given axial node was selected, and a lattice calculation was carried out with MCNP. Comparisons between models using a lattice-averaged void, or using a void distribution in coolant-centered channels, showed large differences in reactivity which in some cases were well above 1,000 pcm, and it also showed differences in normalized fission rates greater than 20%. It was also found that using a lattice average void can lead to a significant difference in the estimation of the worth of a control blade. The differences found when comparing results from models using pin-centered and coolant-centered channels were up to 200 pcm in reactivity and up to 1.4% in the normalized fission rates. In addition to these two sets of comparisons, MCNP models were set up so that each subchannel had a saturated liquid component around the fuel pins and a saturated vapor component in the center to approximate annular flow. In comparison to the models using coolant-centered subchannels, up to 1–3% differences in normalized fission rates could be found.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗