Search NASA⌕ Search

SEARCH · Search NASA

Results for “Capacity Factor”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Interface Aspects in All‐Solid‐State Li‐Based Batteries Reviewed

Abstract Extensive efforts have been made to improve the Li‐ionic conductivity of solid electrolytes (SE) for developing promising all‐solid‐state Li‐based batteries (ASSB). Recent studies suggest that minimizing the existing interface problems is even more important than maximizing the conductivity of SE. Interfaces are essential in ASSB, and their properties significantly influence the battery performance. Interface problems, arising from both physical and (electro)chemical material properties, can significantly inhibit the transport of electrons and Li‐ions in ASSB. Consequently, interface problems may result in interlayer formation, high impedances, immobilization of moveable Li‐ions, loss of active host sites available to accommodate Li‐ions, and Li‐dendrite formation, all causing significant storage capacity losses and ultimately battery failures. The characteristic differences of interfaces between liquid‐ and solid‐type Li‐based batteries are presented here. Interface types, interlayer origin, physical and chemical structures, properties, time evolution, complex interrelations between various factors, and promising interfacial tailoring approaches are reviewed. Furthermore, recent advances in the interface‐sensitive or depth‐resolved analytical tools that can provide mechanistic insights into the interlayer formation and strategies to tailor the interlayer formation, composition, and properties are discussed.

25 ENERGY STORAGE↗
DOE OSTI2018

Efficient multistep arsenate removal onto magnetite modified fly ash

The modification of the fly ash (FA) by magnetite (M) was performed to obtain FAM adsorbent with improved adsorption efficiency for arsenate removal from water. The novel low cost adsorbents are characterized by liquid nitrogen porosimetry (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MB) and Fourier transform infrared (FTIR) spectroscopy. The optimal conditions and key factors influencing the adsorbent synthesis are assessed using the response surface method (RSM). The adsorption experiment was carried out in a batch system by varying the contact time, temperature, pH, and mass of the adsorbent. The adsorption capacity of the FAM adsorbent for As(V), calculated by Langmuir model, was 19.14 mg g−1. The thermodynamic parameters showed spontaneity of adsorption with low endothermic character. The kinetic data followed the pseudo-second-order kinetic model (PSO), and Weber-Morris model indicated intra-particle diffusion as rate limiting step. Alternative to low desorption capability of the FAM was found by five consecutive adsorption/magnetite precipitation processes which gave exhausted layered adsorbent with 65.78 mg g−1 capacity. This research also has shed light on the mechanism of As(V)-ion adsorption, presenting a promising solution for the valorization of a widely abundant industrial waste. © 2018 Elsevier Ltd.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Structure-dependent performance of TiO 2 /C as anode material for Na-ion batteries

The performance of energy storage materials is highly dependent on their nanostructures. Herein, hierarchical rod-in-tube TiO 2 with a uniform carbon coating is synthesized as the anode material for sodium-ion batteries by a facile solvothermal method. This unique structure consists of a tunable nanorod core, interstitial hollow spaces, and a functional nanotube shell assembled from two-dimensional nanosheets. By adjusting the types of solvents used and reaction time, the morphologies of TiO 2 /C composites can be tuned to nanoparticles, microrods, rod-in-tube structures, or microtubes. Among these materials, rod-in-tube TiO 2 with a uniform carbon coating shows the highest electronic conductivity, specific surface area (336.4 m 2 g -1 ), and porosity, and these factors lead to the best sodium storage capability. Benefiting from the unique structural features and improved electronic/ionic conductivity, the as-obtained rod-in-tube TiO 2 /C in coin cell tests exhibits a high discharge capacity of 277.5 and 153.9 mAh g -1 at 50 and 5000 mA g -1 , respectively, and almost 100% capacity retention over 14,000 cycles at 5000 mA g -1 . In operando high-energy X-ray diffraction further confirms the stable crystal structure of the rod-in-tube TiO 2 /C during Na + insertion/extraction. Finally, this work highlights that nanostructure design is an effective strategy to achieve advanced energy storage materials.

25 ENERGY STORAGE↗
DOE OSTI2021

Loss of MBD2 affects early T cell development by inhibiting the WNT signaling pathway

Highlights: • MBD2 deficiency resulted in retardation of T cell differentiation at the DN3 stage. • Decreased proliferative capacity and increased apoptosis were detected in Mbd2{sup −/−} DN thymocytes. • MBD2 affects early T cell development by regulating the expression of key genes of WNT pathway. DNA methylation alters the expression of certain genes without any alteration to the DNA sequence and is a dynamic process during normal hematopoietic differentiation. As an epigenetic regulator, methyl-CpG-binding domain protein 2 (MBD2) is an important member of the MBD protein family and is acknowledged as a “reader” of DNA methylation. We used a mouse model to study the effects of MBD2 on the early development of T cells. Here, we found that MBD2 deficiency led to retardation of T cell differentiation at the DN3 stage. Meanwhile, decreased proliferative capacity and increased apoptosis were detected in Mbd2{sup −/−} DN thymocytes. Furthermore, we found the WNT pathway was significantly down-regulated in Mbd2{sup −/−} DN thymocytes: DKK1 (Dickkopf-1) expression was significantly increased, while TCF7 (transcription factor 7) and c-MYC were down-regulated. Thus, these findings established that MBD2 acted as a dominant regulator to imprint DN T cell development via the WNT pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Drying Temperature and Capillarity-Driven Crack Formation in Aqueous Processing of Li-Ion Battery Electrodes

Unlike conventional electrode processing for Li-ion batteries, which uses the expensive and highly toxic organic N -methyl-2-pyrrolidone (NMP) solvent, aqueous processing simply employs deionized water as the solvent. Yet, thick aqueous processed cathodes have been found to crack during drying. Here, the influence of electrode drying temperature and thickness on cracking was investigated. LiNi 1/3 Mn 1/3 Co 1/3 O 2 cathodes prepared with a hydrophilic binder, modified styrene–butadiene rubber (SBR), were coated at various thicknesses and dried at temperatures ranging from 20 to 70 °C. Experiments revealed cracking worsens with increased electrode thickness and elevated drying temperatures. Cracks were formed during the capillarity-driven phase during drying. Strong evaporation and weak diffusion played a critical role in the nonuniform distribution of the inactive phase. Images of electrode surfaces were processed to quantify crack dimensions and crack intensity factor (CIF). The average crack length and width, as well as CIF, increased with drying temperature and electrode thickness. Electrochemical performance revealed a strong and negative correlation between the crack density and performance in terms of specific capacity. Transport limitations associated with the presence of cracks adversely affect the advantage of high volume ratio of active materials in the thick electrodes.

25 ENERGY STORAGE↗
DOE OSTI2020

Where Are White Roofs More Effective in Cooling the Surface?

Solar reflective roofs (also called white or cool roofs) are a common heat mitigation strategy. By reflecting more sunlight than regular roofs, cool roofs experience lower surface temperatures and produce less heating of the surrounding air. The effectiveness of cool roofs, quantified by the surface temperature difference between cool roofs and regular roofs ??????, is known to vary spatially. A common perception is that ?????? is controlled by solar radiation that reaches the roof surface. Here we use an Earth System Model and a surface energy balance model to show that the spatial variability of ??????, when normalized by the albedo difference between cool roofs and regular roofs (????), is in fact more controlled by an energy distribution factor that encodes the efficiencies of surface energy balance components in dissipating heat. Our results suggest that painting the roof white is more effective in reducing the roof surface temperature when the roof has less water holding capacity and smaller thermal admittance and is located in places with more solar radiation, less precipitation, and lower wind speed.

Wang, Linying↗
DOE OSTI2016

Potential carbon emissions dominated by carbon dioxide from thawed permafrost soils

Increasing temperatures in northern high latitudes are causing permafrost to thaw, making large amounts of previously frozen organic matter vulnerable to microbial decomposition. Permafrost thaw also creates a fragmented landscape of drier and wetter soil conditions that determine the amount and form (carbon dioxide (CO2), or methane (CH4)) of carbon (C) released to the atmosphere. The rate and form of C release control the magnitude of the permafrost C feedback, so their relative contribution with a warming climate remains unclear. We quantified the effect of increasing temperature and changes from aerobic to anaerobic soil conditions using 25 soil incubation studies from the permafrost zone. Here we show, using two separate meta-analyses, that a 10 C increase in incubation temperature increased C release by a factor of 2.0 (95% confidence interval (CI), 1.8 to 2.2). Under aerobic incubation conditions, soils released 3.4 (95% CI, 2.2 to 5.2) times more C than under anaerobic conditions. Even when accounting for the higher heat trapping capacity of CH4, soils released 2.3 (95% CI, 1.5 to 3.4) times more C under aerobic conditions. These results imply that permafrost ecosystems thawing under aerobic conditions and releasing CO2 will strengthen the permafrost C feedback more than waterlogged systemsreleasingCO2 andCH4 for a given amount of C.

Schadel, Christina↗
DOE OSTI2021

Influence of intrinsic and extrinsic attributes on neonate survival in an invasive large mammal

Abstract Understanding factors influencing survival of neonates for wild species is important for successful management, particularly for determining drivers of population dynamics. Wild pigs ( Sus scrofa ) are invasive and populations are rapidly increasing in part due to high reproductive capacity. Survival of adults is generally high, however, survival of piglets, and particularly neonates, is largely unknown. We located neonates at the natal nest and quantified survival in relation to individual and maternal biological attributes, and environmental variables. During 2017–2020, we captured 50 neonates from 13 litters and documented 28 mortalities (56%) over six weeks. Survival was positively influenced by pelage coloration, likely as a form of camouflage from predators. Male neonates had higher survival. They were born larger than females, which could be beneficial for thermoregulation and competition for milk. Neonates born to larger sows had lower survival. Sow size was positively correlated with litter size, and this finding may reflect the increased nutritional demands of sustaining large litters, or difficulties in defending more neonates against predators. Neonates born in warmer months had higher survival than those born in cooler months. Neonates are inefficient thermoregulators, thus being born in warmer months could be beneficial for maintaining homeostasis as well as access to more food resources. These are the largest and most complete data for neonate wild pig survival and will inform population models for the development of management strategies to reduce negative impacts of this destructive invasive species on native ecosystems.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Artificial intelligence inferred microstructural properties from voltage–capacity curves

Abstract The quantification of microstructural properties to optimize battery design and performance, to maintain product quality, or to track the degradation of LIBs remains expensive and slow when performed through currently used characterization approaches. In this paper, a convolution neural network-based deep learning approach (CNN) is reported to infer electrode microstructural properties from the inexpensive, easy to measure cell voltage versus capacity data. The developed framework combines two CNN models to balance the bias and variance of the overall predictions. As an example application, the method was demonstrated against porous electrode theory-generated voltage versus capacity plots. For the graphite|LiMn $$_2$$ 2 O $$_4$$ 4 chemistry, each voltage curve was parameterized as a function of the cathode microstructure tortuosity and area density, delivering CNN predictions of Bruggeman’s exponent and shape factor with 0.97 $$R^2$$ R 2 score within 2 s each, enabling to distinguish between different types of particle morphologies, anisotropies, and particle alignments. The developed neural network model can readily accelerate the processing-properties-performance and degradation characteristics of the existing and emerging LIB chemistries.

25 ENERGY STORAGE↗
DOE OSTI2014

Design and development of liquid filled polymeric fibers with flexure rate viscoelastic properties

The design and development of a novel category of bi-component polymeric fibers, made of a polymeric sheath and a liquid core is described. To understand and to analyze the flow of molten polymer and liquid within a spin pack, we built a macroscale analogon where co-flow of polymer and liquid is investigated systematically. The macroscale analogon is composed of a glass cylinder with a finite length and a coaxial capillary. The inner fluid flows in the capillary and at its outlet meets the outer fluid flowing inside the glass cylinder. The fluids are pumped into the setup using pressurized bottles with controlled flow rates. A high-speed camera is placed in front of the glass cylinder to record the transient and the steady flow of the two phases and the morphology of their interface during co-flow. We systematically analyzed the combination of various fluids and different injection channel geometries, and used these findings to design a customized spin pack. Extrusion trials with molten polymers and specific liquids resulted in the production of liquid filled polymeric fibers (LFF) with different amounts of liquid from 3% to 33%vol. and diameters from 150μm to 1mm. Fiber morphology has been investigated with the help of optical microscopy and computer tomography, in order to analyze both surface and core morphology. Mechanical characterization of fibers has been carried out with special care to the damping capacity of such fibers using two different methods: two point bending tests to evaluate the energy dissipation of fibers upon bending at low frequency values (0.005-0.5Hz), and analysis of vibration reduction to determine the quality factor at the resonance frequency of the 1{sup st} and 3{sup rd} vibration mode.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Modeling and sensitivity analysis of mass transfer in active multilayer polymeric film for food applications

The barrier performance of multilayer polymeric films for food applications has been significantly improved by incorporating oxygen scavenging materials. The scavenging activity depends on parameters such as diffusion coefficient, solubility, concentration of scavenger loaded and the number of available reactive sites. These parameters influence the barrier performance of the film in different ways. Virtualization of the process is useful to characterize, design and optimize the barrier performance based on physical configuration of the films. Also, the knowledge of values of parameters is important to predict the performances. Inverse modeling and sensitivity analysis are sole way to find reasonable values of poorly defined, unmeasured parameters and to analyze the most influencing parameters. Thus, the objective of this work was to develop a model to predict barrier properties of multilayer film incorporated with reactive layers and to analyze and characterize their performances. Polymeric film based on three layers of Polyethylene terephthalate (PET), with a core reactive layer, at different thickness configurations was considered in the model. A one dimensional diffusion equation with reaction was solved numerically to predict the concentration of oxygen diffused into the polymer taking into account the reactive ability of the core layer. The model was solved using commercial software for different film layer configurations and sensitivity analysis based on inverse modeling was carried out to understand the effect of physical parameters. The results have shown that the use of sensitivity analysis can provide physical understanding of the parameters which highly affect the gas permeation into the film. Solubility and the number of available reactive sites were the factors mainly influencing the barrier performance of three layered polymeric film. Multilayer films slightly modified the steady transport properties in comparison to net PET, giving a small reduction in the permeability and oxygen transfer rate values. Scavenging capacity of the multilayer film increased linearly with the increase of the reactive layer thickness and the oxygen absorption reaction at short times decreased proportionally with the thickness of the external PET layer.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Functional team selection as a framework for local adaptation in plants and their belowground microbiomes

Abstract Multicellular organisms are hosts to diverse communities of smaller organisms known as microbiomes. Plants have distinctive microbiomes that can provide important functions related to nutrition, defense, and stress tolerance. Empirical studies provide convincing evidence that in some—but not all—circumstances, belowground microbiomes help plants adapt to their local environment. The purpose of this review is to develop functional team selection (FTS) as a framework to help predict the conditions necessary for root microbiomes to generate local adaptation for their plant hosts. FTS envisions plants and their microbiomes as complex adaptive systems, and plant adaptations as emergent properties of these systems. If plants have the capacity to recognize and cultivate beneficial microbes and suppress pathogens, then it is possible for plants to evolve the capacity to gain adaptations by curating their microbiome. In resource-limited and stressful environments, the emergent functions of complex microbial systems may contribute to positive feedback linked to plant vigor, and ultimately, local adaptation. The key factors in this process are: (i) selective force, (ii) host constitution, (iii) microbial diversity, and (iv) time. There is increasing interest in harnessing beneficial microbial interactions in agriculture and many microbial growth-promoting products are commercially available, but their use is controversial because a large proportion of these products fail to consistently enhance plant growth. The FTS framework may help direct the development of durable plant-microbiome systems that enhance crop production and diminish pathogens. It may also provide valuable insights for understanding and managing other kinds of host-microbe systems.

Environmental Sciences & Ecology↗
DOE OSTI2011

Thermodynamic functions of degenerate magnetized electron gas

The Fermi energy, pressure, internal energy, entropy, and heat capacity of completely degenerate relativistic electron gas are calculated by numerical methods. It is shown that the maximum admissible magnetic field on the order of 10{sup 9} G in white dwarfs increases the pressure by a factor of 1.06 in the central region, where the electron concentration is {approx}10{sup 33} cm{sup -3}, while the equilibrium radius increases by approximately a factor of 1.03, which obviously cannot be observed experimentally. A magnetic field of {approx}10{sup 8} G or lower has no effect on the pressure and other thermodynamic functions. It is also shown that the contribution of degenerate electron gas to the total pressure in neutron stars is negligible compared to that of neutron gas even in magnetic fields with a maximum induction {approx}10{sup 17} G possible in neutron stars. The neutron beta-decay forbiddeness conditions in a superstrong magnetic field are formulated. It is assumed that small neutron stars have such magnetic fields and that pulsars with small periods are the most probable objects that can have super-strong magnetic fields.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Incorporating Pump-and-Treat Performance Assessment Into Hanford Remedy Documents

Performance assessment of a pump-and-treat (P&T) system to support a decision about whether it is appropriate to shut down the system can be facilitated by using a structured approach that included consideration of decision elements. Decision elements involve assessment of contaminant concentrations and trends; contaminant mass discharge from source areas; the attenuation capacity of the aquifer; estimated future plume behavior; and P&T system design, operational, and cost information to identify an appropriate condition for transitioning from P&T remediation. It is also important to consider site-specific factors. Thus P&T system performance assessment for the Hanford Site should be specific to the plumes, environmental setting, and design/operational approaches for Hanford Site P&T systems. In fiscal year 2017, PNNL worked with 200-ZP-1 operable unit (OU) and 100-HR-3 OU staff in preparing OU documents associated with implementation of P&T remedies. In these efforts, elements of a structured approach to P&T decisions and Hanford-specific factors were incorporated into the documents. Because the 200-ZP-1 and 100-HR-3 OU documents are still in a draft stage at the time this report was written, the information provided here serves only as an example of how to map P&T decision elements to performance monitoring and work plans for P&T systems. Final remedy documentation for these OUs should be consulted for specific information on OU plans and activities.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Snohomish Public Utility District MESA 2: An Assessment of Flow Battery Energy Storage System Technical Performance

This report investigates the technical performance of the 2.2 MW, 8 MWh MESA 2 advanced vanadium flow battery energy storage system (FBESS), consisting of four 0.55 MW, 2 MWh strings, based on a number of baseline and use case tests. The FBESS is located at the Everett, Washington substation and owned by SnoPUD. The FBESS was procured by SnoPUD with matching funds by the Washington Clean Energy. Baseline tests were intended to assess the general technical capability of the FBESS (e.g., stored energy capacity, ramp rate performance, ability to track varying charge/discharge commands, direct current (DC) battery internal resistance). Use case tests were used to examine the performance of the FBESS while engaged in specific grid services (e.g., arbitrage, power factor correction). The project measured and/or calculated parameters that are important for understanding FBESS performance when subjected to actual field operation for achieving economic benefits, e.g., round trip efficiency (RTE) with and without rest, with and without auxiliary loads, auxiliary power consumption, signal command tracking, temperature trends during operation, parasitic power loss unaccounted by auxiliary load during rest, and state of charge (SOC) excursions. These baseline and use case parameters were analyzed using recorded test results. In addition, the results and lessons presented herein are also beneficial for any task or effort that needs technical assessment on similar and different types of FBESS based on technical specifications and/or field deployment results, since the assessment methodology remains the same.

25 ENERGY STORAGE↗
DOE OSTI2019

Puget Sound Energy Glacier Energy Storage System: An Assessment of Battery Technical Performance

This report investigates the technical performance of the Glacier BESS facility, consisting of one 2 MW, 4 MWh BESS, based on a number of baseline and use case tests. Baseline tests were intended to assess the general technical capability of the BESS (e.g., stored energy capacity, ramp rate performance, ability to track varying charge/discharge commands, direct current (DC) battery internal resistance). Use case tests were used to examine the performance of the BESS while engaged in specific economic services (e.g., arbitrage, power factor correction). The project measured and/or calculated parameters that are important for understanding BESS performance when subjected to actual field operation for achieving economic benefits, e.g., round trip efficiency (RTE) with and without rest, with and without auxiliary loads, auxiliary power consumption, signal command tracking performance, temperature variations, parasitic power loss during power electronics switching during rest, and state of charge (SOC) excursions. These baseline and use case parameters were analyzed using recorded test results. In addition, the results and lessons presented herein are also beneficial for any task or effort that needs technical assessment on similar and different types of BESS based on field deployment results, since the assessment methodology remains the same.

25 ENERGY STORAGE↗
DOE OSTI2015

Drought-influenced mortality of tree species with different predawn leaf water dynamics in a decade-long study of a central US forest

Using decade-long continuous observations of tree mortality and predawn leaf water potential (ψ pd ) at the Missouri Ozark AmeriFlux (MOFLUX) site, we studied how the mortality of important tree species varied and how such variations may be predicted. Water stress determined inter-annual variations in tree mortality with a time delay of 1 year or more, which was correlated fairly tightly with a number of quantitative predictors formulated based on ψ pd and precipitation regimes. Predictors based on temperature and vapor pressure deficit anomalies worked reasonably well, particularly for moderate droughts. The exceptional drought of the year 2012 drastically increased the mortality of all species, including drought-tolerant oaks, in the subsequent year. The drought-influenced tree mortality was related to the species position along the spectrum of ψ pd regulation capacity with those in either ends of the spectrum being associated with elevated risk of death. Regardless of species and drought intensity, the ψ pd of all species recovered rapidly after sufficiently intense rain events in all droughts. This result, together with a lack of immediate leaf and branch desiccation, suggests an absence of catastrophic hydraulic disconnection in the xylem and that tree death was caused by significant but indirect effects. Species differences in the capacity of regulating ψ pd and its temporal integral were magnified under moderate drought intensities but diminished towards wet and dry extremes. Severe droughts may overwhelm the capacity of even drought-tolerant species to maintain differential levels of water potential as the soil becomes exhausted of available water in the rooting zone, thus rendering them more susceptible to death if predisposed by other factors such as age.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1984

Advance Technology Satellites in the Commercial Environment. Volume 2: Final Report

A forecast of transponder requirements was obtained. Certain assumptions about system configurations are implicit in this process. The factors included are interpolation of baseline year values to produce yearly figures, estimation of satellite capture, effects of peak-hours and the time-zone staggering of peak hours, circuit requirements for acceptable grade of service capacity of satellite transponders, including various compression methods where applicable, and requirements for spare transponders in orbit. The graphical distribution of traffic requirements was estimated.

Source record↗