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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 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Nonlinear Optical Properties of Organic and Polymeric Thin Film Materials of Potential for Microgravity Processing Studies

In this paper, we will take a closer look at the state of the art of polydiacetylene, and metal-free phthalocyanine films, in view of the microgravity impact on their optical properties, their nonlinear optical properties and their potential advantages for integrated optics. These materials have many attractive features with regard to their use in integrated optical circuits and optical switching. Thin films of these materials processed in microgravity environment show enhanced optical quality and better molecular alignment than those processed in unit gravity. Our studies of these materials indicate that microgravity can play a major role in integrated optics technology. Polydiacetylene films are produced by UV irradiation of monomer solution through an optical window. This novel technique of forming polydiacetylene thin films has been modified for constructing sophisticated micro-structure integrated optical patterns using a pre-programmed UV-Laser beam. Wave guiding through these thin films by the prism coupler technique has been demonstrated. The third order nonlinear parameters of these films have been evaluated. Metal-free phthalocyanine films of good optical quality are processed in our laboratories by vapor deposition technique. Initial studies on these films indicate that they have excellent chemical, laser, and environmental stability. They have large nonlinear optical parameters and show intrinsic optical bistability. This bistability is essential for optical logic gates and optical switching applications. Waveguiding and device making investigations of these materials are underway.

Abdeldayem, Hossin↗
DOE OSTI2016

hapter 10 - Challenges and Opportunities for the Mobilisation of Forest Bioenergy in the Boreal and Temperate Biomes. In the book Mobilisation of Forest Bioenergy in the Boreal and Temperate Biomes.

This book identifies opportunities and challenges for the mobilisation of sustainable forest biomass from supply chains operating in the boreal and temperate biomes. The respective feedstock plays a critical role in meeting global deployment levels for bioenergy, which in turn are necessary to stabilize global greenhouse gas emissions and atmospheric carbon levels. Many aspects of bioenergy supply chains (e.g., logistics and trade, supply chain variability, technology learning and transfer, governance, organizational structures) present both challenges and opportunities, and relate to all three dimensions of sustainability. Energy and forest systems can be integrated across landscapes and organizations to establish attractive solutions guided by good governance of forest management and biomass use (e.g., policies, regulations, standards and certification systems). Nevertheless, substantial gains in forest bioenergy mobilisation can only be achieved with an important increase in forest management intensity causing a larger appropriation of forest net primary production (NPP). Such an intensification would likely require fundamental shifts in the forest systems and considerable societal change in some countries. A multifaceted policy effort to support a broad array of technological, structural, and behavioral changes is needed to enable energy and industrial transitions and the development of supply chains that deliver feedstock to a range of conversion and utilization routes.

09 BIOMASS FUELS↗
DOE OSTI2018

Centrifugal particle confinement in mirror geometry

The use of supersonic rotation of a plasma in mirror geometry has distinct advantages for thermonuclear fusion. The device is steady state, there are no disruptions, the loss cone is almost closed, sheared rotation stabilizes magnetohydrodynamic instabilities as well as plasma turbulence, there are no runaway electrons, and the coil configuration is simple. In this work, we examine the effect of rotation on mirror confinement using a full cyclotron orbit code. The full cyclotron simulations give a much more complete description of the particle energy distribution and losses than the use of guiding center equations. Both collisionless loss as a function of rotation and the effect of collisions are investigated. Although the cross field diffusion is classical, we find that the local rotating Maxwellian is increased to higher energy, increasing the fusion rate and also enhancing the radial diffusion. We find a loss channel not envisioned with a guiding center treatment, but a design can be chosen that can satisfy the Lawson criterion for ions. Of course, the rotation has a minimal effect on the alpha particle birth distribution, so there is initially loss through the usual loss cone, just as in a mirror with no rotation. However after this loss, the alphas slow down on the electrons with little pitch angle scattering until reaching low energy, so over half of the initial alpha energy is transferred to the electrons. The important problem of energy confinement, with losses primarily through the electron channel, is not addressed in this work. In conclusion, we also discuss the use of rotating mirror geometry to produce an ion thruster.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Anomalous transport in the H-mode pedestal of Alcator C-Mod discharges

Anomalous transport in the H-mode pedestal region of five Alcator C-Mod discharges, representing a collisionality scan is analyzed. The understanding of anomalous transport in the pedestal region is important for the development of a comprehensive model for the H-mode pedestal slope. In this research, a possible role of the drift resistive inertial ballooning modes (Rafiq et al 2010 Phys. Plasmas 17 082511) in the edge of Alcator C-Mod discharges is analyzed. The stability analysis, carried out using the TRANSP code, indicates that the DRIBM modes are strongly unstable in Alcator C-Mod discharges with large electron collisionality. An improved interpretive analysis of H-mode pedestal experimental data is carried out utilizing the additive flux minimization technique (Pankin et al 2013 Phys. Plasmas 20 102501) together with the guiding-center neoclassical kinetic XGC0 code. The neoclassical and neutral physics are simulated in the XGC0 code and the anomalous fluxes are computed using the additive flux minimization technique. The anomalous fluxes are reconstructed and compared with each other for the collisionality scan Alcator C-Mod discharges. It is found that the electron thermal anomalous diffusivities at the pedestal top increase with the electron collisionality. This dependence can also point to the drift resistive inertial ballooning modes as the modes that drive the anomalous transport in the plasma edge of highly collisional discharges.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Polyalkylene Glycol (PAG) Based Lubricant for Light & Medium Duty Axles

The axle lubricant (SAE 75W-140) widely used in the market place over the last few years is primarily formulated from polyalpha olefin (PAO) basestock. This investigation focused on polyalkylene glycol (PAG) base stock which is significantly different chemically from PAO and because of their polar nature it is hypothesized that it can adsorb relatively easily on contacting surfaces resulting in significant friction reduction and improve fuel economy. Axle efficiency is generally quite high at high torque range but it could be quite low at low torque range representative of EPA drive cycles. Therefore, this project primarily focus on improving axle efficiency in the low torque range while maintaining all durability attributes. The objective of this project is to develop novel lubricant formulations that are expected to improve the fuel efficiency of light, medium, heavy-duty, and military vehicles by at least 2% over Society of Automotive Engineers (SAE) 75W-140 axle lubricants (improvement based on comparative results from engine dynamometer testing, chassis dynamometer testing or test track, e.g., SAE J1321) without adverse impacts on vehicle performance or durability. The proposed research project followed a structured approach beginning with lubricant formulations by varying base oil chemistry and additive components followed by physical property characterization. Lubricant performance evaluations started with simple laboratory friction, wear, oxidation, and corrosion tests which guided into identification of performance areas requiring improvements. This required an iterative lubricant reformulation. Once a few acceptable formulations were identified, they are evaluated in more complex component tests including ASTM tests (L-37 - load carrying capacity under low speed and high torque, L42 – load carrying properties under high speed and shock loading, L-60 - thermal and oxidative stability, and L-33-1 moisture corrosion resistance). Two issues were observed following L-42 tests; toxicological and foaming. This required reformulation and repeating all ASTM tests. During repeat tests it was observed that some of the additives precipitated out of solution. Since it was discovered quite late in the program, and the time it may need to find a solution to this issue, the team changed direction of the program to switch to use of an oil soluble PAG as a co-basestock (15-30%) with mineral oil used in a commercial formulation (SAE 75W-85). This formulation strategy helped passing all ASTM tests. This was followed by Ford proprietary axle efficiency, gear wear, and chassis roll dynamometer tests for fuel economy evaluations. Axle efficiency was improved up to 7% when a full PAG formulation was used but no such significant improvement was observed with PAG as co-basestock formulation. Chassis roll fuel economy improved by 1.9% with PAG co-basestock formulation (conforming to SAE 75W-85) compared to SAE 75W-140 baseline. However, it was observed that the improvement is mostly due to reduced viscosity of candidate formulation when compared to a full mineral oil based SAE 75W-85 formulation. PAG as co-basestock also exhibited unacceptable wear in proprietary gear wear test. This investigation highlighted challenges with PAG formulations including identification of additive components that stay in PAG solution for intended duration, and meeting component durability requirement.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Anomalous transport in the H-mode pedestal of Alcator C-Mod discharges

Anomalous transport in the H-mode pedestal region of five Alcator C-Mod discharges, representing a collisionality scan is analyzed. The understanding of anomalous transport in the pedestal region is important for the development of a comprehensive model for the H-mode pedestal slope. In this research, a possible role of the drift resistive inertial ballooning modes (Rafiq et al 2010 Phys. Plasmas 17 082511) in the edge of Alcator C-Mod discharges is analyzed. The stability analysis, carried out using the TRANSP code, indicates that the DRIBM modes are strongly unstable in Alcator C-Mod discharges with large electron collisionality. An improved interpretive analysis of H-mode pedestal experimental data is carried out utilizing the additive flux minimization technique (Pankin et al 2013 Phys. Plasmas 20 102501) together with the guiding-center neoclassical kinetic XGC0 code. The neoclassical and neutral physics are simulated in the XGC0 code and the anomalous fluxes are computed using the additive flux minimization technique. The anomalous fluxes are reconstructed and compared with each other for the collisionality scan Alcator C-Mod discharges. It is found that the electron thermal anomalous diffusivities at the pedestal top increase with the electron collisionality. This dependence can also point to the drift resistive inertial ballooning modes as the modes that drive the anomalous transport in the plasma edge of highly collisional discharges.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Friends or Foes: Fundamental Principles of Th-Organic Scaffold Chemistry Using Zr-Analogs as a Guide

The fundamental interest in actinide chemistry, particularly for the development of thorium-based materials, is experiencing a renaissance owing to the recent and rapidly growing attention to fuel cycle reactors, radiological daughters for nuclear medicine, and efficient nuclear stockpile development. Herein, we uncover fundamental principles of thorium chemistry on the example of Th-based extended structures such as metal–organic frameworks in comparison with the discrete systems and zirconium extended analogs, demonstrating remarkable over two-and-half-year chemical stability of Th-based frameworks as a function of metal node connectivity, amount of defects, and conformational linker rigidity through comprehensive spectroscopic and crystallographic analysis as well as theoretical modeling. Despite exceptional chemical stability, we report the first example of studies focusing on the reactivity of the most chemically stable Th-based frameworks in comparison with the discrete Th-based systems such as metal–organic complexes and a cage, contrasting multicycle recyclability and selectivity (>97%) of the extended structures in comparison with the molecular compounds. Altogether, the presented work not only establishes the conceptual foundation for evaluating the capabilities of Th-based materials but also represents a milestone for their multifaceted future and foreshadows their potential to shape the next era of actinide chemistry.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Understanding slurry formulations to guide solution-processing of solid electrolytes

Scalable processing of thin solid electrolytes is crucial for engineering solid-state batteries with practical energy densities. To leverage existing battery production infrastructure, pathways for solution processing of solid electrolyte films must be investigated. Here, roll-to-roll compatible film preparation of aluminum-doped lithium lanthanum zirconate oxide was studied. Four slurry configurations accounting for different solvent properties and solid loadings were evaluated to investigate the ternary interactions within the dispersions. Rheological and coating stability analyses were carried out on the processed slurries. The analysis and characterization indicated that improved component interactions within the ethanol/toluene system result in homogenized distribution of the particles, binder, and plasticizer, and enable the extraction of free-standing thin films with thicknesses of 20 μm and large area (>15 in. 2 ). The drawbacks and opportunities of several protocols for high temperature sintering of the dried green films were investigated. This study highlights the importance of engineering dispersions during the development of processing protocols for solid electrolytes and provides guidelines for the best practices that can be leveraged for solution processing–based fabrications for a wide range of solid electrolyte materials.

25 ENERGY STORAGE↗
DOE OSTI2025

A critical review of electrochemical heat pump technologies: Status, challenges, and perspectives

The development of advanced heat pump technologies is critical for reducing global energy consumption in the building sector, where space heating and cooling account for nearly 50% of energy use. Electrochemical heat pumps (EHPs) offer a promising alternative to vapor compression systems by enabling direct electrochemical-to-thermal energy conversion, often with environmentally benign working fluids that exhibit low or zero global warming potential (GWP). Prior literature has predominantly focused on chemically reactive heat pumps, while comprehensive assessments of electrochemical mechanisms remain limited. Here, this review addresses this gap by systematically evaluating the underlying principles, architectures, and performance metrics of EHP systems. Compared to conventional vapor compression systems, EHPs can achieve 10%-30% higher energy efficiency, with reported cooling coefficients of performance (COP c ) ranging from 3.5 to 14.3 under standard operating conditions. Despite these advantages, widespread adoption is hindered by challenges including membrane degradation, electrode fouling, sluggish redox kinetics, and elevated system-level capital costs. To address these limitations, the review outlines three research priorities: (i) the development of advanced membranes, catalysts, and electrode materials with enhanced chemical and mechanical stability; (ii) the application of molecular-level simulations for the rational design of high-performance redox-active working fluids; and (iii) the integration of advanced diagnostic techniques for real-time monitoring and sustained operation of EHPs. By consolidating recent advances and explicitly identifying technological and scientific gaps, this work uniquely contributes a comprehensive framework for guiding future electrochemical heat pump research and facilitating the transition to sustainable thermal management technologies.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Synergistic Anion and Solvent-Derived Interphases Enable Lithium-Ion Batteries under Extreme Conditions

Lithium-ion batteries (LIBs) face increasingly stringent demands as their application expands into new areas, including extreme temperatures and fast charging. To meet these demands, the electrolyte should enable fast lithium-ion transport and form stable interphases on electrodes simultaneously. In practice, however, improving one aspect often compromises another. For instance, the trend toward electrolytes forming anion-derived interphases typically reduces transport efficiency due to weak-solvating solvents. Here, we propose that instead of relying on anions to form the interphase, leveraging both solvents and anions to form interphases can potentially lead to a balancing point between robust interphase formation and effective ion transport. Guided by this design principle, 2,2-difluoroethyl ethyl carbonate (DFDEC) was identified as the promising solvent. With the new electrolyte using DFDEC as the major solvent and lithium bis(fluorosulfonyl) imide (LiFSI) as the salt, graphite||LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) full cells are capable of fast charging and demonstrate long-term cycling stability with a cutoff voltage of 4.5 V. Notably, the battery shows a capacity retention of 84.3% after 500 cycles with an average Coulombic efficiency (CE) as high as 99.93%. This new electrolyte also enables stable battery cycling across a wide temperature range (-20 to 60 °C), with excellent capacity retention.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2019

The Effect of Ring Expansion in Thienobenzo[ b ]indacenodithiophene Polymers for Organic Field-Effect Transistors

A fused donor, thienobenzo[b]indacenodithiophene (TBIDT), was designed and synthesized using a novel acid-promoted cascade ring closure strategy, and then copolymerized with a benzothiadiazole (BT) monomer. The backbone of TBIDT is an expansion of the well-known indacenodithiophene (IDT) unit and was expected to enhance the charge carrier mobility by improving backbone planarity and facilitating short contacts between polymer chains. However, the optimized field-effect transistors demonstrated an average saturation hole mobility of 0.9 cm 2 V -1 s -1 , lower than the performance of IDT-BT (~1.5 cm 2 V -1 s -1 ). Mobilities extracted from time-resolved microwave conductivity measurements were consistent with the trend in hole mobilities in organic field-effect transistor devices. Scanning tunneling microscopy measurements and computational modeling illustrated that TBIDT-BT exhibits a less ordered microstructure in comparison to IDT-BT. This reveals that a regular side-chain packing density, independent of conformational isomers, is critical to avoid local free volume due to irregular packing, which can host trapping impurities. DFT calculations indicated that TBIDT-BT, despite containing a larger, planar unit, showed less stabilization of planar backbone geometries in comparison to IDT-BT. This is due to the reduced electrostatic stabilizing interactions between the peripheral thiophene of the fused core and the BT unit, resulting in a reduction of the barrier to rotation around the single bond. Finally, these insights provide a greater understanding of the general structure-property relationships required for semiconducting polymer repeat units to ensure optimal backbone planarization, as illustrated with IDT-type units, guiding the design of novel semiconducting polymers with extended fused backbones for high-performance field-effect transistors.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Many routes to ferroelectric HfO 2 : A review of current deposition methods

Although 10 years have passed since the initial report of ferroelectricity in hafnia (HfO 2 ), researchers are still intensely fascinated by this material system and the promise it holds for future applications. A wide variety of deposition methods have been deployed to create ferroelectric HfO 2 thin films such as atomic layer deposition, chemical solution deposition, and physical vapor deposition methods such as sputtering and pulsed laser deposition. Process and design parameters such as deposition temperature, precursor choice, target source, vacuum level, reactive gases, substrate strain, and many others are often integral in stabilizing the polar orthorhombic phase and ferroelectricity. We examine processing parameters across four main different deposition methods and their effect on film microstructure, phase evolution, defect concentration, and resultant electrical properties. The goal of this review is to integrate the process knowledge collected over the past 10 years in the field of ferroelectric HfO 2 into a single comprehensive guide for the design of future HfO 2 -based ferroelectric materials and devices.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Density characterization of discharged gas-filled capillaries through common-path two-color spectral-domain interferometry

Electrically discharged plasma structures, typically several centimeters in length and sub-millimeter in diameter, have been applied to guide laser pulses in laser plasma accelerators and to focus ion and relativistic electron beams in compact, radially symmetric transport configurations. Knowledge of the on-axis plasma density is critical. Traditional density interferometry has been ineffective for these laser-machined structures, while group velocity delay (GVD) techniques involve combining two laser paths with corresponding alignment complexities and stability sensitivities. Here the GVD technique is advanced to a common-path two-color interferometer configuration performed in the spectral domain of a broad-bandwidth femtosecond laser. Multi-shot tracking of the phase is not required, and the common path assures improved stability. Here, this in situ technique was validated on 15 mm long plasma structures, measuring electron densities of 10 17 -10 18 cm -3 for various fill pressures.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1976

Low subsonic aerodynamic characteristics of five irregular planform wings with systematically varying wing fillet geometry tested in the NASA/Ames 12 foot pressure tunnel (LA65)

An experimental and analytical aerodynamic program to develop predesign guides for irregular planform wings (also referred to as cranked leading edge or double delta wings is reported; the benefits are linearization of subsonic lift curve slope to high angles of attack and avoidance of subsonic pitch instabilities at high lift by proper tailoring of the planform-fillet-wing combination while providing the desired hypersonic trim angle and stability. Because subsonic and hypersonic conditions were the two prime areas of concern in the initial application of this program to optimize shuttle orbiter landing and entry characteristics, the study was designated the Subsonic/Hypersonic Irregular Planforms Study (SHIPS).

Ball, J. W.↗
NASA NTRS2006

Instrument Pointing Control System for the Stellar Interferometry Mission - Planet Quest

This paper describes the high precision Instrument Pointing Control System (PCS) for the Stellar Interferometry Mission (SIM) - Planet Quest. The PCS system provides front-end pointing, compensation for spacecraft motion, and feedforward stabilization, which are needed for proper interference. Optical interferometric measurements require very precise pointing (0.03 as, 1-(sigma) radial) for maximizing the interference pattern visibility. This requirement is achieved by fine pointing control of articulating pointing mirrors with feedback from angle tracking cameras. The overall pointing system design concept is presentcd. Functional requirements and an acquisition concept are given. Guide and Science pointing control loops are discussed. Simulation analyses demonstrate the feasibility of the design.

control↗
DOE OSTI2025

Phase change material integrated core–shell catalyst for in situ thermal control in methanol synthesis from syngas

A model-guided core–shell catalyst design is presented for methanol synthesis, featuring a phase change material (PCM) core encapsulated by a Cu–Zn–Al 2 O 3 (CZA) catalytic shell. The PCM enables in situ thermal management by absorbing reaction heat at its melting point, mitigates the kinetic decline at high temperatures and therefore avoids low conversion, prevents hot spots, and stabilizes the reaction temperature. A two-dimensional axisymmetric, non-isothermal packed-bed reactor model (COMSOL 6.3) was developed for a 10 g system. Simulations evaluate three PCM candidates, that is, LiNO 3 , 9 wt% LiCl + 91 wt% LiNO 3 , and commercial H250, with melting points near 244–250°C. Results indicate that CO conversion can increase from 34.4% to 52.4%, and methanol production can improve by 69% compared to a conventional packed-bed reactor. Beyond methanol synthesis, the PCM-integrated core–shell concept provides a scalable approach for thermal control in exothermic reactions, improving reactor efficiency and safety.

core–shell catalyst↗
DOE OSTI2026

Role of Elemental Substitution on Hydrogen Incorporation in Characteristic Ti/Fe-Based Oxides

Elemental substitution is well-known to benefit hydrogen storage in the intermetallic compound TiFe; however, the impact of these substituents on the native and passivating surface oxide has not been well-established. Here, we perform density functional theory calculations on several characteristic oxides that are likely to form on exposed TiFe surfaces, specifically, TiO 2 , FeO, TiFeO 3 , and Ti 4 Fe 2 O. In TiO 2 and TiFeO 3 , additional acceptor species substituting for Ti can increase the solubility of protonic hydrogen (H i + ), likely enhancing hydrogen permeation of the oxide layer. In FeO, few dopants will act as acceptors, and hydrogen will incorporate as substitutional H O + , which is likely to be less mobile and will hinder hydrogen permeation. Finally, we find that Ti 4 Fe 2 O, which is thermodynamically metastable, may be stabilized by defects under O-poor conditions, although the presence of certain substitutional elements can destabilize it. In general, Mn, V, and Cr are among the best substituents for enhancing hydrogenation through the oxide layer. In conclusion, our results help to explain what features make additional elements particularly effective for enabling reversible hydrogen storage in TiFe, and they can guide further technological development of high-performing TiFe-based alloys for future energy applications.

organic↗
DOE OSTI2025

Nanoscopic strain evolution in single-crystal battery positive electrodes

Single-crystal Ni-rich layered oxides (SC-NMC) with a grain-boundary-free configuration have effectively addressed the long-standing cracking issue of conventional polycrystalline Ni-rich materials (PC-NMC) in lithium-ion batteries, prompting a shift in optimization strategies. However, continued reliance on anisotropic lattice volume change—a well-established failure indicator in PC-NMC—as a metric for understanding strain and guiding compositional design for SC-NMC becomes controversial. Here, in this study, by leveraging multiscale diagnostic techniques, we unravelled the distinct nanoscopic strain evolution in SC-NMC during battery operation, challenging the conventional composition-driven strategies and mechanical degradation indicators used for PC-NMC. Through particle-level chemomechanical analysis, we reveal a decoupling between mechanical stability and lattice volume change in SC-NMC, identifying that structural instability in SC materials is primarily driven by multidimensional lattice distortions induced by kinetics-driven reaction heterogeneity and progressively deactivating chemical phases. Using this mechanical failure mode, we redefine the roles of cobalt and manganese in maintaining mechanical stability. Unlike cobalt’s detrimental role in PC-NMC, we find cobalt to be critical in enhancing the longevity of SC-NMC by mitigating localized strain along the extended diffusion pathway, whereas manganese exacerbates mechanical degradation.

36 MATERIALS SCIENCE↗