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At least 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Defining Golden Batches in Biomanufacturing Processes From Internal Metabolic Activity to Detect Process Changes That May Affect Product Quality

ABSTRACT Cellular metabolism plays a role in the observed variability of a drug substance's Critical Quality Attributes (CQAs) made by biomanufacturing processes. Therefore, here we describe a new approach for monitoring biomanufacturing processes that measures a set of metabolic reaction rates (named Critical Metabolic Parameters (CMP) in addition to the macroscopic process conditions currently being used as Critical Process Parameters (CPP) for biomanufacturing. Constraint‐based systems biology models like Flux Balance Analysis (FBA) are used to estimate metabolic reaction rates, and metabolic rates are used as inputs for multivariate Batch Evolution Models (BEM). Metabolic activity was reproducible among batches and could be monitored to detect a deliberately induced macroscopic process shift (i.e., temperature change). The CMP approach has the potential to enable “golden batches” in biomanufacturing processes to be defined from the internal metabolic activity and to aid in detecting process changes that may impact the quality of the product. Overall, the data suggested that monitoring of metabolic activity has promise for biomanufacturing process control.

Biotechnology & Applied Microbiology↗
DOE OSTI2021

Axion strings are superconducting

We explore the cosmological consequences of the superconductivity of QCD axion strings. Axion strings can support a sizeable chiral electric current and charge density, which alters their early universe dynamics. We examine the possibility that shrinking axion string loops can become effectively stable remnants called vortons, supported by the repulsive electromagnetic force of the string current. We find that vortons in our scenario are generically unstable, and so do not pose a cosmological difficulty. Furthermore, if a primordial magnetic field (PMF) exists in the early universe, a large current is induced on axion strings, creating a significant drag force from interactions with the surrounding plasma. As a result, the strings are slowed down, which leads to an orders of magnitude enhancement in the number of strings per Hubble volume. Finally, we study potential implications for the QCD axion relic abundance. The QCD axion window is shifted by orders of magnitude in some parts of our parameter space.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Effect of Sulfur in Steel on Transient Evolution of Inclusions During Calcium Treatment

In the current study, the effect of S content in the molten steel on inclusions during calcium treatment was studied using an induction furnace. The calcium in steel decreased from 48 to 2 ppm, and the sulfur in steel changed a little with time. When sulfur content in steel was as low as 25 ppm during calcium treatment, inclusions shifted from CaO-Al{sub 2}O{sub 3}-CaS to Al{sub 2}O{sub 3}-CaO with about 35 pct CaO. When the sulfur increased over 90 ppm, more CaS-CaO formed just after the addition of calcium, and then the CaS content decreased from over 45 pct to lower than 15 pct and inclusions were mostly Al{sub 2}O{sub 3}-CaO-CaS and Al{sub 2}O{sub 3}-CaO with a high Al{sub 2}O{sub 3} content. Thermodynamic calculation predicted the variation of the composition of inclusions, indicating good agreement with the measurement, while a certain deviation existed, especially for heats with 90 and 180 ppm sulfur. A reaction model was proposed for the formation of CaO and CaS, which considered the reaction between calcium vapor bubbles in the zone and the dissolved oxygen and sulfur in the molten steel, as described by a Langmuir-type adsorption isotherm with a reaction occurring on the remaining vacant sites. The variation of transient CaS inclusions was discussed based on the thermodynamic calculation and the morphology evolution of typical inclusions containing CaS.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Vanishing carrier-envelope-phase-sensitive response in optical-field photoemission from plasmonic nanoantennas

At the surfaces of nanostructures, enhanced electric fields can drive optical-field photoemission and thereby generate and control electrical currents at frequencies exceeding 100 THz. A hallmark of such optical-field photoemission is the sensitivity of the total emitted current to the carrier-envelope phase (CEP). In this work, we examine CEP-sensitive photoemission from plasmonic gold nanoantennas excited with few-cycle optical pulses. At a critical pulse energy, which we call a vanishing point, we observe a pronounced dip in the magnitude of the CEP-sensitive photocurrent accompanied by a sudden shift of π radians in the photocurrent phase. Analysis shows that this vanishing behaviour arises due to competition between sub-optical-cycle electron emission events from neighbouring optical half-cycles and that both the dip and phase shift are highly sensitive to the precise shape of the driving optical waveform at the surface of the emitter. As the mechanisms underlying the dip and phase shift are a general consequence of nonlinear, field-driven photoemission, they may be used to probe sub-optical-cycle emission processes from solid-state emitters, atoms and molecules. Improved understanding of these CEP-sensitive photocurrent features will be critical to the development of optical-field-driven photocathodes for time-domain metrology and microscopy applications demanding attosecond temporal and nanometre spatial resolution.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Continuum Modeling of Inductor Hysteresis and Eddy Current Loss Effects in Resonant Circuits

This paper presents experimental validation of a high-fidelity toroid inductor modeling technique. The aim of this research is to accurately model the instantaneous magnetization state and core losses in ferromagnetic materials. Quasi–static hysteresis effects are captured using a Preisach model. Eddy currents are included by coupling the associated quasi-static Everett function to a simple finite element model representing the inductor cross sectional area. The modeling technique is validated against the nonlinear frequency response from two different series RLC resonant circuits using inductors made of electrical steel and soft ferrite. The method is shown to accurately model shifts in resonant frequency and quality factor. The technique also successfully predicts a discontinuity in the frequency response of the ferrite inductor resonant circuit.

Pries, Jason L.↗
DOE OSTI2017

Computational Modeling of Fluctuations in Energy and Metabolic Pathways of Methanogenic Archaea

The methanogenic archaea, anaerobic microbes that convert CO2 and H2 and/or other small organic fermentation products into methane, play an unusually large role in the global carbon cycle. As they perform the final step in the anaerobic breakdown of biomass, methanogens are a biogenic source of an estimated one billion tons methane each year. Depending on the location, produced methane can be considered as either a greenhouse gas (agricultural byproduct), sequestered carbon storage (methane hydrate deposits), or a potential energy source (organic wastewater treatment). These microbes therefore represent an important target for biotechnology applications. Computational models of methanogens with predictive power are useful aids in the adaptation of methanogenic systems, but need to connect processes of wide-ranging time and length scales. In this project, we developed several computational methodologies for modeling the dynamic behavior of entire cells that connects stochastic reaction-diffusion dynamics of individual biochemical pathways with genome-scale modeling of metabolic networks. While each of these techniques were in the realm of well-defined computational methods, here we integrated them to develop several entirely new approaches to systems biology. The first scientific aim of the project was to model how noise in a biochemical pathway propagates into cellular phenotypes. Genetic circuits have been optimized by evolution to regulate molecular processes despite stochastic noise, but the effect of such noise on a cellular biochemical networks is currently unknown. An integrated stochastic/systems model of Escherichia coli species was created to analyze how noise in protein expression gives—and therefore noise in metabolic fluxes—gives rise to multiple cellular phenotype in isogenic population. After the initial work developing and validating methods that allow characterization of the heterogeneity in the model organism E. coli, the project shifted toward investigations of the methanogen Methanosarcina acetivorans. By integrating an unprecedented transcriptomics dataset for growth of the methanogen on many substrates with an in silico model, heterogeneity in metabolic pathway usage and methane production were examined. This lent insight into the physiological requirements of the organism under different environmental conditions and uncovered the unique regulatory role that mRNA half-life has in shaping metabolic flux distributions in this organism.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Regulators’ Energy Transition Primer: Economic Impacts of the Energy Transition on Energy Communities, Environmental Justice Considerations, and Implications on Clean Energy Jobs

Applications of new technology, such as horizontal drilling and hydraulic fracturing, enabled the United States to significantly increase its production of oil and natural gas during the last decade—the “Shale Gas Revolution.” As natural gas began to dominate the market with abundant supply and low prices, coal production and consumption have declined. Concurrently, the competitiveness of renewable energy and energy storage has climbed sharply, and analysts expect to see continued reductions in fossil fuel use in the coming decades. Many of these changes have been driven by market forces (i.e., low-cost natural gas and renewables), but current and future policy decisions aimed at tackling climate change concerns and reducing greenhouse gas emissions will also shape the future of the energy sector. This transition to low-carbon fuels has created both opportunities for clean energy technologies and challenges for communities traditionally dependent on fossil fuel-related industries. The power sector’s ongoing shift away from coal has left many coal miners and coal-fired power plant employees unemployed and often unprepared for jobs in other industries, including growing clean energy fields. This primer focuses on the declining coal industry, impacts on communities and workers, opportunities to transition workers who have lost their jobs to clean energy and other related sectors (including hydrogen-oriented jobs), recruitment and training strategies, and available programs and actions to make the shift to a low-carbon economy in a fair, just, and equitable manner by engaging the resources of federal and state governments, as well as the private sector.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2026

Communications Reliability for Vehicle Grid Integration

Electric Vehicles (EVs) adoption rate has been steadily increasing in the US leading to a growing number of charging stations including faster DC (Direct Current) chargers and slower Level 1 and Level 2 AC (Alternating Current) chargers. This increase in demand for electricity is further exacerbated by recent developments in Artificial Intelligence (AI) technology, advanced manufacturing, and digitization. These factors will require electric utilities to upgrade their infrastructure to keep up with the increasing electrical demand (especially during peak hours). An easy way to counteract the need for these upgrades is to shift a major chunk of active charge sessions (durations where there is energy transfer from charger to EV's propulsion battery) to off-peak hours thereby flattening the load curve and making the infrastructure more resilient. This concept is known as Smart Charge Management (SCM). EV owners also benefit from SCM since it lowers their charging costs and consequently their transportation costs by prioritizing charging during off-peak hours. SCM takes advantage of EV's capability to act as a controllable load or DER (Distributed Energy Resource). This report summarizes the reliability analysis performed on the communication required for two of these SCM use-cases. This analysis only focuses on SCM strategies for unidirectional charging (energy transfer from EVSE to EV or V1G) and not bidirectional charging.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2020

Systematic Uncertainties of the NOvA Neutrino Oscillation Analysis

NOvA is a two detector long-baseline neutrino oscillation experiment using Fermilab’s 700 kW NuMI muon neutrino beam. It studies the disappearance of muon (anti)neutrinos and the appearance of electron (anti)neutrinos in the beam over a distance of 810 km between the detectors. The observations can be used to constrain neutrino oscillation parameters: $\theta_{23}, \Delta m_{32}^2$ and $\delta_{CP}$ in the standard 3 active neutrinos paradigm. Although statistical uncertainties currently dominate in these measurements, understanding the major sources of systematic uncertainties and their correlations is vital for both the interpretation and precision of the results and also for further improvements of the analysis. This note presents details of the systematic uncertainties affecting NOvA's neutrino oscillation analysis results and how we evaluate them by generating systematically shifted predictions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Direct Formation and Structural Characterization of Electride C12A7

Ca 12 Al 14 O 33 (C12A7 or Mayenite) is a material whose caged clathrate structure and occluded anionic species leads to significant functionality. The creation of occluded anionic vacancies leads to the injection of localized electrons at the center of the cage, converting the wide band gap insulator to a semi- or metallic conducting material. The conversion to the electride historically requires the synthesis of oxy-C12A7, consolidation, and then reduction to introduce anionic vacancies. This report develops and characterizes an electride formation procedure from three starting points: unconsolidated oxy-C12A7, heterogenous solid-state reactants (CaCO 3 and Al 2 O 3 ), and homogenous non-carbonaceous polymer assisted sol-gel reactants. Electride-C12A7 formation is observed in a vacuum furnace where the reactants are in direct contact with a carbon source. Process time and temperature-dependent structural characterization provides insight into the source of high temperature C12A7 stability, the mechanism of anionic vacancy formation, and the magnitude of ultimate conductivity that cannot be explained by current reduction theories. A new theory is presented where mixed O- and C-occupied cages lead to high temperature stability, oxidation of C species creates anionic vacancies, and an equilibrium between the reducing power of the electride-C12A7 and of the C species leads to the ultimate conductivity achieved by the process. This represents a shift in understanding of the carbonaceous reduction process and the first report of high purity electride-C12A7 formation from heterogenous solid-state reactants and homogenous non-carbonaceous polymer assisted sol-gel reactants.

36 MATERIALS SCIENCE↗
DOE OSTI2017

First Weak-lensing Results from “See Change”: Quantifying Dark Matter in the Two z ≳ 1.5 High-redshift Galaxy Clusters SPT-CL J2040–4451 and IDCS J1426+3508

We present a weak-lensing study of SPT-CL J2040–4451 and IDCS J1426+3508 at z = 1.48 and 1.75, respectively. The two clusters were observed in our “See Change” program, a Hubble Space Telescope survey of 12 massive high-redshift clusters aimed at high-z supernova measurements and weak-lensing estimation of accurate cluster masses. We detect weak but significant galaxy shape distortions using infrared images from the Wide Field Camera 3 (WFC3), which has not yet been used for weak-lensing studies. Both clusters appear to possess relaxed morphology in projected mass distribution, and their mass centroids agree nicely with those defined by both the galaxy luminosity and X-ray emission. Using a Navarro–Frenk–White profile, for which we assume that the mass is tightly correlated with the concentration parameter, we determine the masses of SPT-CL J2040–4451 and IDCS J1426 + 3508 to be M{sub 200}=8.6{sub −1.4}{sup +1.7}×10{sup 14} M{sub ⊙} and 2.2{sub −0.7}{sup +1.1}×10{sup 14} M{sub ⊙}, respectively. The weak-lensing mass of SPT-CL J2040–4451 shows that the cluster is clearly a rare object. Adopting the central value, the expected abundance of such a massive cluster at z≳1.48 is only ∼0.07 in the parent 2500 sq. deg. survey. However, it is yet premature to claim that the presence of this cluster creates a serious tension with the current ΛCDM paradigm unless that tension will remain in future studies after marginalizing over many sources of uncertainties such as the accuracy of the mass function and the mass–concentration relation at the high-mass end. The mass of IDCS J1426+3508 is in excellent agreement with our previous Advanced Camera for Surveys-based weak-lensing result, while the much higher source density from our WFC3 imaging data makes the current statistical uncertainty ∼40% smaller.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Late Holocene evolution of a coupled, mud-dominated delta plain–chenier plain system, coastal Louisiana, USA

Abstract. Major deltas and their adjacent coastal plains are commonly linked by means of coast-parallel fluxes of water, sediment, and nutrients. Observations of the evolution of these interlinked systems over centennial to millennial timescales are essential to understand the interaction between point sources of sediment discharge (i.e. deltaic distributaries) and adjacent coastal plains across large spatial (i.e. hundreds of kilometres) scales. This information is needed to constrain future generations of numerical models to predict coastal evolution in relation to climate change and other human activities. Here we examine the coastal plain (Chenier Plain, CP) adjacent to the Mississippi River delta, one of the world's largest deltas. We use a refined chronology based on 22 new optically stimulated luminescence and 22 new radiocarbon ages to test the hypothesis that cyclic Mississippi subdelta shifting has influenced the evolution of the adjacent CP. We show that over the past 3 kyr, accumulation rates in the CP were generally 0–1 Mt yr −1 . However, between 1.2 and 0.5 ka, when the Mississippi River shifted to a position more proximal to the CP, these rates increased to 2.9 ±1.1 Mt yr −1 or 0.5–1.5 % of the total sediment load of the Mississippi River. We conclude that CP evolution during the past 3 kyr was partly a direct consequence of shifting subdeltas, in addition to changing regional sediment sources and modest rates of relative sea-level (RSL) rise. The RSL history of the CP during this time period was constrained by new limiting data points from the base of overwash deposits associated with the cheniers. These findings have implications for Mississippi River sediment diversions that are currently being planned to restore portions of this vulnerable coast. Only if such diversions are located in the western portion of the Mississippi Delta plain could they potentially contribute to sustaining the CP shoreline. Our findings highlight the importance of a better understanding of mud-dominated shorelines that are often associated with major deltas, in light of the enormous investments in coastal management and restoration that will likely be made around the globe, now and especially later during this century.

Hijma, Marc P.↗
NASA NTRS1983

Weak dynamical effects in the Uranian ring system

Published data on the orbits of the rings and satellites of Uranus are analyzed in terms of their dynamic interaction, in an attempt to explain discrepancies between current kinematic models of the ring system and recent, very accurate occultation observations. Apse precession, short-term perturbations, satellite resonance, and the movement of the planet and rings with respect to the barycenter of the planet-satellite system are investigated. It is found that the five known satellites could cause the observed ring residuals by shifting the barycenter, but not by direct or resonance effects. Hypothetical interring shepherd satellites of limited mass (such as about 10 to the 19th g for a shepherd between rings 4 and 5), possibly affected by known-satellite resonances, could influence the rings directly.

Freedman, A. P.↗
NASA NTRS1988

Comparison of field-aligned currents at ionospheric and magnetospheric altitudes

Using the empirical terrestrial magnetospheric magnetic field models of Tsyganenko and Usmanov (1982) and Tsyganenko (1987) the average field-aligned currents (FACs) in the magnetosphere were determined as a function of the Kp index. Three major model FAC systems were identified, namely, the dayside region 1, the nightside region 1, and the nightside polar cap. The models provide information about the sources of the current systems. Mapped ionospheric model FACs are compared with low-altitude measurements obtained by the spacecraft. It is found that low-altitude data can reveal either classic region 1/2 or more highly structured FAC patterns. Therefore, statistical results either obtained from observations or inferred from models are expected to be averages over temporally and spatially shifting patterns.

Spence, H. E.↗
NASA NTRS1999

Monitoring Global Geophysical Fluids by Space Geodesy

Since its establishment on 1/1/1998 by the International Earth Rotation Service, the Coordinating Center for Monitoring Global Geophysical Fluids (MGGF) and its seven Special Bureaus have engaged in an effort to support and facilitate the understanding of the geophysical fluids in global geodynamics research. Mass transports in the atmosphere-hydrosphere-solid Earth-core system (the "global geophysical fluids") will cause the following geodynamic effects on a broad time scale: (1) variations in the solid Earth's rotation (in length-of-day and polar motion/nutation) via the conservation of angular momentum and effected by torques at the fluid-solid Earth interface; (2) changes in the global gravitational field according to Newton's gravitational law; and (3) motion in the center of mass of the solid Earth relative to that of the whole Earth ("geocenter") via the conservation of linear momentum. These minute signals have become observable by space geodetic techniques, primarily VLBI, SLR, GPS, and DORIS, with ever increasing precision/accuracy and temporal/spatial resolution. Each of the seven Special Bureaus within MGGF is responsible for calculations related to a specific Earth component or aspect -- Atmosphere, Ocean, Hydrology, Ocean Tides, Mantle, Core, and Gravity/Geocenter. Angular momenta and torques, gravitational coefficients, and geocenter shift will be computed for geophysical fluids based on global observational data, and from state-of-the-art models, some of which assimilate such data. The computed quantities, algorithm and data formats are standardized. The results are archived and made available to the scientific research community. This paper reports the status of the MGGF activities and current results.

Chao, Benjamin F.↗
NASA NTRS2014

Human-Automation Cooperation for Separation Assurance in Future NextGen Environments

A 2012 Human-In-The-Loop air traffic control simulation investigated a gradual paradigm-shift in the allocation of functions between operators and automation. Air traffic controllers staffed five adjacent high-altitude en route sectors, and during the course of a two-week experiment, worked traffic under different function-allocation approaches aligned with four increasingly mature NextGen operational environments. These NextGen time-frames ranged from near current-day operations to nearly fully-automated control, in which the ground systems automation was responsible for detecting conflicts, issuing strategic and tactical resolutions, and alerting the controller to exceptional circumstances. Results indicate that overall performance was best in the most automated NextGen environment. Safe operations were achieved in this environment for twice todays peak airspace capacity, while being rated by the controllers as highly acceptable. However, results show that sector operations were not always safe; separation violations did in fact occur. This paper will describe in detail the simulation conducted, as well discuss important results and their implications.

air traffic control↗
NASA NTRS1991

Gravitational lenses: The current sample, recent results, and continuing searches

Gravitational lensing is one of the topics in astrophysics that was quite extensively discussed over time before it was actually discovered. Ten years after the discovery of the first one, it is interesting to note how the field has developed. After an initial slow rate of discovery, the last few years have seen an explosion in the number of reported cases. Attention was drawn to the first few cases because quasars at the same red shift, with similar optical spectra, were observed with angular separations of only a few arc seconds. Most observational effort has been devoted to searching for new candidate lens systems and carefully measuring their properties, both to test whether they are indeed lensed and to provide constraints for modeling. A classification of the lenses is into rings, arcs, multiples, and doubles, where the progression is from sources close to the optical axis to far from the optical axis. The known candidate systems are listed. The searches for gravitational lenses are proving to be successful, and more lenses continue to be discovered serendipitously. Many searches are under way, along with instruments that will routinely increase the resolution of astronomical imaging.

Hewitt, Jacqueline N.↗
DOE OSTI2023

Material Effects on Electron-Capture Decay in Cryogenic Sensors

Several current searches for physics beyond the standard model are based on measuring the electron-capture (EC) decay of radionuclides implanted into cryogenic high-resolution sensors. The sensitivity of these experiments has already reached the level where systematic effects related to atomic state energy changes from the host material are a limiting factor. One example is a neutrino mass study based on the nuclear EC decay of 7 Be to 7 Li inside cryogenic Ta-based sensors. Here, to understand the material effects at the required level, we use density-functional theory to model the electronic structure of lithium atoms in different atomic environments of the polycrystalline Ta absorber film. The calculations reveal that the Li 1s binding energies can vary by more than 2 eV due to insertion at different lattice sites, at grain boundaries, in disordered Ta, and in the vicinity of various impurities. However, the total range of Li 1s shifts does not exceed 4 eV, even for extreme amorphous disorder. Furthermore, when investigating the effects on the Li 2s levels, we find broadening of more than 5 eV due to hybridization with the Ta band structure. Material effects are shown to contribute significantly to peak broadening in Ta-based sensors that are used to search for physics beyond the standard model in the EC decay of 7 Be, but they do not explain the full extent of observed broadening. Understanding these in-medium effects will be required for current- and future-generation experiments that observe low-energy radiation from the EC decay of implanted isotopes to evaluate potential limitations on the measurement sensitivity.

36 MATERIALS SCIENCE↗