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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Engineering Saccharomyces cerevisiae for co-utilization of d-galacturonic acid and d-glucose from citrus peel waste

Pectin-rich biomasses, such as citrus peel and sugar beet pulp, hold promise as inexpensive feedstocks for microbial fermentations as enzymatic hydrolysis of their component polysaccharides can be accomplished inexpensively to yield high concentrations of fermentable sugars and D-galacturonic acid (D-galUA). In this study, we tackle a number of challenges associated with engineering a microbial strain to convert pectin-rich hydrolysates into commodity and specialty chemicals. First, we engineer D-galUA utilization into yeast, Saccharomyces cerevisiae . Second, we identify that the mechanism of D-galUA uptake into yeast is mediated by hexose transporters and that consumption of D-galUA is inhibited by D-glucose. Third, we enable co-utilization of D-galUA and D-glucose by identifying and expressing a heterologous transporter, GatA, from Aspergillus niger . Last, we demonstrate the use of this transporter for production of the platform chemical, meso -galactaric acid, directly from industrial Navel orange peel waste.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Chapter 15: Immobilization of Microalgae as a Tool for Efficient Light Utilization in H2 Production and Other Biotechnology Applications

This chapter highlights recent advances in the field of whole-cell immobilization technology that can improve the yield of H2 photoproduction in microalgae. Low light utilization efficiency in suspension cultures, expensive biomass harvesting, and high energy demand for cell cultivation and maintenance of photobioreactors are among the major barriers limiting the use of green algae and other photosynthetic microorganisms for light-driven, industrial, and biotechnological applications. We review current immobilization approaches that address the above barriers and describe novel techniques used for separating microalgal cells from the liquid phase inside a photobioreactor. Special attention is given to a thin-layer, immobilization procedure, which shows potential to revolutionize the use of microalgal catalysts for more efficient light utilization and conversion of light energy to stored energy in the form of H2 gas and other biofuels or end-products.

09 BIOMASS FUELS↗
DOE OSTI2019

Cooperative valorization of lignin and residual sugar to polyhydroxyalkanoate (PHA) for enhanced yield and carbon utilization in biorefineries

Lignin valorization is essential for a sustainable and economically viable biorefinery. Despite the recent efforts, it is still unclear how the reactivity of native lignin can be improved by pretreatment in a biorefinery and how different components in biorefinery residue especially residual sugar contribute to bioconversion in biorefineries. In the present study, co-utilization of lignin and limited glucose was first evaluated and proved to facilitate lignin conversion and polyhydroxyalkanoate (PHA) production. A new integrated biorefinery was then designed to cooperatively valorize lignin and residual sugar for improving the PHA yield and utilization efficiency of biorefinery residue. By the design of integrated biorefinery, the glucose and xylose yield were 91% and 73%, respectively, which increased by 18% and 12% compared with that only using sodium hydroxide pretreatment. Approximately 85% of the lignin was dissolved into a liquid stream with the integrated biorefinery, corresponding to an increase of 69% compared with that only using sodium hydroxide pretreatment. More than 70% of the residual sugar was released from the biorefinery residue, producing the soluble lignin stream that contains both lignin and residual sugar for synergistic bioconversion. Bioconversion of the soluble lignin stream with Pseudomonas putida KT2440 produced 1.5 g l -1 PHA, representing the record titer of PHA from biorefinery residue. The lignin characterization results from nuclear magnetic resonance and gel-permeation chromatography showed that the integrated process significantly reduced the lignin molecular weight, broke down more β-O-4 and β-5 linkages, and enriched the H-lignin content. Alongside the increased residual sugar concentration, the bioconversion performance of soluble lignin to PHA was significantly improved. Altogether, the integrated biorefinery increased the fermentable sugar yield and improved the PHA production from biorefinery waste by cooperative valorization of lignin and residual sugar, which shows potential advantages for biorefinery sustainability.

09 BIOMASS FUELS↗
DOE OSTI2016

Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus

Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.

42 ENGINEERING↗
DOE OSTI2022

Reaction processes at step edges on S-decorated Cu(111) and Ag(111) surfaces: MD analysis utilizing machine learning derived potentials

We report a variety of complexation, reconstruction, and sulfide formation processes can occur at step edges on the {111} surfaces of coinage metals (M) in the presence of adsorbed S under ultra-high vacuum conditions. Given the cooperative many-atom nature of these reaction processes, Molecular Dynamics (MD) simulation of the associated dynamics is instructive. However, only quite restricted Density Functional Theory (DFT)-level ab initio MD is viable. Thus, for M = Ag and Cu, we instead utilize the DeePMD framework to develop machine-learning derived potentials, retaining near-DFT accuracy for the M–S systems, which should have broad applicability. These potentials are validated by comparison with DFT predictions for various key quantities related to the energetics of S on M(111) surfaces. The potentials are then utilized to perform extensive MD simulations elucidating the above diverse restructuring and reaction processes at step edges. Key observations from MD simulations include the formation of small metal–sulfur complexes, especially MS 2 ; development of a local reconstruction at A-steps featuring an S-decorated {100} motif; and 3D sulfide formation. Additional analysis yields further information on the kinetics for metal–sulfur complex formation, where these complexes can strongly enhance surface mass transport, and on the propensity for sulfide formation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Radiation, optical, power flow, and electrical diagnostics at the Z facility: Layout and techniques utilized to operate in the harsh environment

The Z machine is a current driver producing up to 30 MA in 100 ns that utilizes a wide range of diagnostics to assess accelerator performance and target behavior conduct experiments that use the Z target as a source of radiation or high pressures. Here, we review the existing suite of diagnostic systems, including their locations and primary configurations. The diagnostics are grouped in the following categories: pulsed power diagnostics, x-ray power and energy, x-ray spectroscopy, x-ray imaging (including backlighting, power flow, and velocimetry), and nuclear detectors (including neutron activation). We will also briefly summarize the primary imaging detectors we use at Z: image plates, x-ray and visible film, microchannel plates, and the ultrafast x-ray imager. The Z shot produces a harsh environment that interferes with diagnostic operation and data retrieval. We term these detrimental processes “threats” of which only partial quantifications and precise sources are known. Finally, we summarize the threats and describe techniques utilized in many of the systems to reduce noise and backgrounds.

47 OTHER INSTRUMENTATION↗
DOE OSTI2026

A simplified di-homodyne transient grating spectroscopy system utilizing polarization

Here, a modification to the di-homodyne transient grating spectroscopy optical arrangement is presented that removes the need to individually align two spatially separated probe laser beams. This work details the novel application of a single probe beam that utilizes birefringent materials to produce two optically homodyned signals with a relative phase shift of π radians. This arrangement effectively simplifies the alignment to one probe beam and removes the relative phase shift ambiguity between each homodyned signal. Several example measurements for tungsten, titanium, molybdenum, and silicon are shown to illustrate the utility of the new optical system.

Simmonds, M. J. [Univ. of California, San Diego, C↗
DOE OSTI2024

Utility and Industry Perceptions of Control Room Modernization Over the Last 10 Years

Within the current United States (U.S.) nuclear power fleet, main control room modernization (CRM) is an important step towards cost savings. In recent decades, plants have been engaged in upgrades to varying degrees. This process requires a nuanced, balanced, and timely approach that ensures continued safety and long-term sustainability. In 2012 a survey was issued to individuals from the nuclear industry to learn their perspectives on a range of CRM issues. The survey targeted the benefits and challenges for utilities undertaking this process, including the main drivers and barriers to technology upgrades, regulatory compliance, and the effects these factors have on concepts of operations, strategic approaches, and staffing. In 2022, the survey was issued again to understand whether CRM perceptions had changed in the last 10 years. Our findings identify changes in industry thinking from a decade ago. Here we reveal perspective shifts that represent increased optimism and, in some instances, increased doubt regarding the opportunities and challenges inherent in CRM and implementation. We also report nuanced differences in CRM perspectives between utility and surrounding nuclear industry respondents.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

Valuation of pollination services from habitat management: a case study of utility scale solar energy facilities in the United States

Creating and maintaining pollinator habitats following the ecological infrastructure concept in degraded or unutilized land, such as solar energy facilities, is a practical way to synergistically advance the food, energy, and ecology nexus. Given the large land-use requirements for solar farming—the fastest growing renewable energy technology–considerable attention has been focused on strategies to maximize multiple ecosystem services. In this study, we coupled the principles of agronomy and ecology with economics and integrated national-scale data on crops, pollinators, and solar facilities to identify locations for creating pollinator habitats and estimating the economic value of pollination from the habitats. We examined opportunities for pollination services from pollinator-friendly utility-scale solar facilities adjacent to 42 million hectares of pollination-dependent crops in the conterminous United States at high resolution of 1 ha. We used the net income method to estimate the potential economic value of creating habitat in the land adjacent to solar facilities in the eight states with the greatest number of solar installations. Creating pollinator habitats at the 217 utility-scale solar facilities in these states could support adjacent 80,000 hectares of high pollinator dependent crops, which could potentially generate a pollination value of $\$$120 to $\$$264 million USD. The location-specific information and high-resolution maps generated for the United States demonstrate integration of grey and green infrastructure to support the food, energy, and environment nexus.

14 SOLAR ENERGY↗
DOE OSTI2024

Perturbation of tonoplast sucrose transport alters carbohydrate utilization for seasonal growth and defense metabolism in coppiced poplar

Abstract Nonstructural carbohydrate reserves of stems and roots underpin overall tree fitness and productivity under short-rotation management practices such as coppicing for bioenergy. While sucrose and starch comprise the predominant stem carbohydrate reserves of Populus, utilization for fitness and agricultural productivity is understood primarily in terms of starch turnover. The tonoplast sucrose transport protein SUT4 modulates sucrose export from source leaves to distant sinks during photoautotrophic growth, but the possibility of its involvement in remobilizing carbohydrates from storage organs during heterotrophic growth has not been explored. Here, we used PtaSUT4-knockout mutants of Populus tremula × P. alba (INRA 717-1B4) in winter (cool) and summer (warm) glasshouse coppicing experiments to assess SUT4 involvement in reserve utilization. Conditions preceding and supporting summer sprouting were considered favorable for growth, while those preceding and supporting cool temperature sprouting were suboptimal akin to conditions associated with coppicing as generally practiced. Epicormic bud emergence was delayed in sut4 mutants following lower temperature ‘winter’ but not summer coppicing. Winter xylem hexose increases were observed in control but not in sut4 stumps after coppicing. The magnitude of starch and sucrose reserve depletion was similar in control and sut4 stumps during the winter and did not explain the sprouting and xylem hexose differences. However, winter maintenance costs appeared higher in sut4 based partly on Krebs cycle intermediate levels. In control plants, bark accrual of abundant defense metabolites, including salicinoids and condensed tannins, was higher in summer than in winter, but this increase of summer defense allocations was attenuated in sut4 mutants. Temperature-sensitive trade-offs between growth and other priorities may therefore depend on SUT4 in Populus.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Smart Inverters for Seamless Reconnection of Isolated Residential Microgrids to Utility Grid

This paper proposes an approach to achieve seamless reconnection of isolated residential microgrids to utility grid. Any abnormal condition on the grid side results in isolating the residential microgrid from utility grid, and giving the full responsibility of supplying household loads to local distributed generation (DG) units. However, after resolving the abnormal condition on the grid side, the residential microgrid needs to seamlessly reconnect to the main grid. To this end, a seamless transition algorithm is presented which monitors the system condition in real time, and coordinates the operation of all inverter-based DG units in residential microgrid before reconnection to the main grid. A modified control scheme is proposed for single-phase inverters which turns them into smart inverters enable to interact with seamless transition algorithm. The proposed approach synchronizes each phase voltage with its respective grid-side voltage in order to seamlessly reconnect the residential microgrid to the main grid. Case study results are carried out in PSCAD/EMTDC environment to verify the validity of proposed method.

Pilehvar, Mohsen S.↗
DOE OSTI2021

Peak Load Management in Distribution Systems Using Legacy Utility Equipment and Distributed Energy Resources

The ability to perform peak load management in distribution systems has several benefits for utilities, including reduced demand charges and improved reliability, efficiency, and utilization of the network infrastructure. This paper demonstrates the coordinated operation of an advanced distribution management system (ADMS) and a distributed energy resource management system (DERMS) to achieve peak load management using a realistic laboratory test bed. A commercial ADMS reduces the peak demand by reducing system voltages using a dynamic voltage regulation (DVR) application. A prototype DERMS-based on real-time optimal power flow-controls distributed battery energy storage systems to further reduce the feeder power. Results from the experiments conducted using a model of a real distribution feeder show that the coordinated operation of the ADMS and DERMS is effective in accomplishing peak load management.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Balancing Charging Station Utilization and Throughput in Electric Vehicle Charging Stations with Queuing Theory

The rapid increase in electric vehicle (EV) adoption demands enhancements in the efficiency and adaptability of EV supply equipment (EVSE). Traditional EVSE systems often fail to optimize power delivery to meet the variable acceptance rates of EV batteries, resulting in significant energy wastage and reduced operational efficiency. This research addresses these challenges by integrating queuing theory with modular EVSE architectures, offering a dual strategy to optimize the operation of EV charging stations. A simulation model was developed to assess various configurations of charger capacities and outlet numbers. This model aimed to identify the optimal setup that maximizes station utilization while minimizing charging times and maximizing throughput. The model focused on charger capacities ranging from 50 to 250 kW and analyzed the different capacities’ effects on charging times and the number of vehicles served. The results indicate that a charger capacity of 125 kW is optimal, striking a balance between the charging time and the number of EVs served per hour, thus achieving the highest station utilization rate. This capacity allows for servicing a significant number of EVs with moderate increases in charging times. Lower capacities, although capable of serving more vehicles, lead to longer charging times and decreased throughput efficiency. The study underscores the effectiveness of combining queuing theory with flexible, modular charging systems that can dynamically adjust to EV charging demands.

Kumar, Praveen↗
DOE OSTI2019

Field Validated Utility-Scale Battery Storage Control Models for Quasi-Static Analyses

This paper presents a co-simulation based approach to implement and validate advanced battery storage control modes in OpenDSS that replicate behavior of a utility scale vanadium red-ox flow battery (VRFB). Inverter-interfaced utiliy-scale battery storage systems (BSS) have modes of operation to facilitate multiple grid-support functions. In order to enable accurate understanding of the impacts from grid-support functions modes of operation it is required to develop validated models that replicates behavior of the actual control system. This paper presents the pseudo code for the implemented control schemes including peak shaving and capacity firming control modes. Additionally, this paper also provides insight on convergence sensitivity of the presented algorithms to related parameters. The results obtained from simulation studies will be compared against field operated utility-scale BSS measurements to verify the implemented algorithms.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2025

Exploring the Utility-Privacy Trade-Off: Impacts of Semantic and Visit Types Ambiguities on Human Mobility Simulation

Humans are in perpetual movement, constantly traversing buildings, cities, waters, oceans, and countries. Mobility stands out as a major driving force shaping our modern societies. Capturing and explaining human behavior in a world of eight billion distinct mobility agendas is a complex challenge. With the rise of interconnected devices and platforms, such as smartphones, wearables, and point-of-interest data, largescale behavioral data has become more accessible, enabling rich insights into mobility patterns. However, the widespread availability of such data introduces significant ethical challenges. Detailed mobility data can inadvertently reveal sensitive personal information, including individuals' locations, habits, social interactions, and even political or religious affiliations. Beyond privacy breaches, the ethical implications of uncovering and potentially manipulating underlying behavioral patterns demand attention. Striking a balance between the utility of mobility models and the protection of individual privacy is therefore paramount. This paper explores the utility-privacy trade-offs in human mobility modeling, focusing on the impacts of introducing semantic and visit type ambiguities. By systematically examining how these ambiguities affect the fidelity of simulated trajectories and privacy risks, we provide a framework for evaluating ethical and privacy-conscious modeling practices. Our findings emphasize the need for methods that safeguard privacy without undermining the usefulness of mobility models, contributing to the responsible advancement of mobility science in alignment with ethical standards and societal expectations.

Amichi, Licia [ORNL] (ORCID:0000000177631394)↗
DOE OSTI2020

Ubiquitous Power Electronics in Future Power Systems: Recommendations to fully utilize fast control capabilities

Power electronics is becoming ubiquitous in power systems because the rapid growth of variable renewable generation such as wind and solar, responsive load, electric vehicles, energy storage, as well as DC transmission. As a result, a high percentage of electricity will be generated, transmitted or consumed by power electronics in the future power system. Such a high penetration of power electronics is changing power system operation landscapes and dynamic characteristics. Two major kinds of impact are reduced system mechanical inertia by inverter-based resources displacing conventional generation and active participation of many distributed energy resources through inverters. This has caused significant reliability challenges for power system operation. The mitigation approach so far has mostly focused on accommodating power electronics inverters as passive devices or creating synthetic inertias to make inverter-based generation behaving as conventional generators. However, the high-speed control capabilities of power electronics present new opportunities for achieving an optimal performance beyond conventional power systems. A lower-inertia system can be more responsive for improving reliability, and distributed small resources can be more adaptive and scalable for better flexibility and resilience. Power electronic inverters are capable of multiple fast control functions. To fully utilized the ubiquitous power electronics in power systems requires technology advancements in the following areas: data and communications to capture the new dynamic behaviors introduced by power electronics; modeling and simulation to understand the behaviors of power electronics and its interactions with other components in the context of power systems; control and optimization methods for fully utilizing the capabilities of power electronics for a new paradigm of performance beyond the traditional inertia-heavy system; and significant upgrades in power electronics hardware to cater to the new control capabilities. If properly controlled and optimized, power electronics can help transform the power system to be responsive, adaptive, and scalable.

Huang, Zhenyu↗
DOE OSTI2017

Defense strategies for asymmetric networked systems under composite utilities

We consider an infrastructure of networked systems with discrete components that can be reinforced at certain costs to guard against attacks. The communications network plays a critical, asymmetric role of providing the vital connectivity between the systems. We characterize the correlations within this infrastructure at two levels using (a) aggregate failure correlation function that specifies the infrastructure failure probability giventhe failure of an individual system or network, and (b) first order differential conditions on system survival probabilities that characterize component-level correlations. We formulate an infrastructure survival game between an attacker and a provider, who attacks and reinforces individual components, respectively. They use the composite utility functions composed of a survival probability term and a cost term, and the previously studiedsum-form and product-form utility functions are their special cases. At Nash Equilibrium, we derive expressions for individual system survival probabilities and the expected total number of operational components. We apply and discuss these estimates for a simplified model of distributed cloud computing infrastructure

Rao, Nageswara S.↗