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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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DOE OSTI2025

Variationally consistent Maxwell stress in flexoelectric structures under finite deformation and immersed in free space

Maxwell stress refers to the mechanical stress exerted on a dielectric material due to the presence of electric fields. It plays a significant role in the interaction between a dielectric material and the surrounding free space under finite deformation. Previous research on finite deformation of flexoelectricity mainly adopted a modified form of Maxwell stress, potentially not able to correctly capture some physical phenomena, such as the compression of a dielectric droplet in an electric field. In this work, we propose a consistent and complete variational principle for flexoelectricity, in which the Maxwell stress emerges naturally from the derivation, without introducing additional assumptions. An Isogeometric analysis-based numerical framework is developed accordingly and verified by both linear and nonlinear benchmark cases compared with experimental results. The present framework successfully captures and quantifies the behaviors of conductive liquids and soft dielectric solids subjected to an external electric field. Finally, a novel scenario is investigated in which a flexoelectric beam immersed in free space is analyzed, showing the interesting distribution of Maxwell stress-induced tractions at opposing boundaries. The test demonstrates that a higher dielectric constant can effectively enhance the material's stiffness in response to the external electric loading.

36 MATERIALS SCIENCE↗

DOE OSTI2026

Effects of 9.5 Years of Whole-Soil Warming on the Fatty Acid and n-Alkanes Composition in Bulk Soil and Density Fractions at Blodgett Experimental Forest, California, USA

Original data of molecular data (fatty acids and n-alkanes) including concentrations and calculated molecular proxies in a whole-soil warming experiment at the Blodgett Forest Research Station after 9.5 years of warming. The study site has a Mediterranean climate with annual average temperature of 12.5 ℃ and annual average precipitation of 1774 mm. The study site is characterized by a mesic Ultic Alfisol formed from granitic parent material, corresponding to a Dystric Cambisol under the World Reference Base for Soil Resources (WRB) classification system. Experimental warming is applied throughout the soil profile to a depth of 1 m using vertically embedded heating cables that raise soil temperature by 4 °C relative to ambient conditions. Soil samples were collected on 1 May 2023, after the experiment had been operating continuously for about 9.5 years since its initiation in January 2014.The data has been processed from raw data and cross-validated by other peers. The dataset includes: - Bulk_Fattyacid_9.5-year_Soil_Warming_Blodgett, California, USA: fatty acid concentrations and proxies including Carbon Preference Index (CPI) and Average Chain Length (ACL) of bulk soil organic carbon; - Fractions_Fattyacid_9.5-year_Soil_Warming_Blodgett, California, USA: fatty acid concentrations and proxies including CPI and ACL of free particulate organic matter (fPOM) and mineral-associated organic matter (MAOM); - Bulk_Alkanes_9.5-year_Soil_Warming_Blodgett, California, USA: n-alkanes concentrations and proxies including CPI and ACL of bulk soil organic carbon; - Fractions_Alkanes_9.5-year_Soil_Warming_Blodgett, California, USA: n-alkanes concentrations and proxies including CPI and ACL of fPOM and MAOM; - n-Alkanes_All_Monomer_Concentration_9.5-year_Soil_Warming_Blodgett, California, USA: concentration of all the n-alkane monomers identified and integrated for bulk soil, fPOM and MAOM; - Fattyacid_All_Monomer_Concentration_9.5-year_Soil_Warming_Blodgett, California, USA: concentration of all the fatty acid monomers including diacids identified and integrated for bulk soil, fPOM, and MAOM. All data are provided in CSV format and can be viewed using Microsoft Excel. We specifically look at fatty acids (FA) and n-alkanes in bulk soil, fPOM and MAOM and calculated molecular proxies such as CPI and ACL to understand the source of oragnic carbon (with ACL) and degree of decomposition (CPI) of each soil fraction. Due to lack of long-chain fatty acids (carbon number ⩾ 20), microorganism-derived organic carbon is characterized by shorter ACL in comparison to plant-derived organic carbon. Fresh SOC is characterized by even-over-odd dominance for fatty acids and odd-over-even dominance for n-alkanes. Therefore, CPI indicates whether soil organic carbon (SOC) represents fresh input (CPI > 10) or is strongly decomposed (close to 1). The research questions should be then, after 9.5-year warming: 1. whether the relative contribution between microorganism-derived and plant-derived SOC in each soil fraction? 2. whether fPOM became more decomposed whereas MAOM remained relatively persistent in each soil fraction across the soil depth?

Carbon↗

NASA NTRS1970

Metal detector system

Signal voltage resulting from the disturbance of an electromagnetic field within the volume of a sensitive area is compared with a reference ac voltage for polarity information, which identifies the material. System output amplitude and polarity indicate approximate size and type of metal, respectively.

Lee, R. D.↗

NASA NTRS1973

Turbine Design and Application, Volume 2

NASA has an interest in turbines related primarily to aeronautics and space applications. Airbreathing turbine engines provide jet and turboshaft propulsion, as well as auxiliary power for aircraft. Propellant -driven turbines provide rocket propulsion and auxiliary power for spacecraft. Closed-cycle turbine engines using inert gases, organic fluids, and metal fluids have been studied for providing long-duration electric power for spacecraft. Other applications of current interest for turbine engines include land-vehicle (cars, trucks, buses, trains, etc.) propulsion power and ground-based electrical power. In view of the turbine-system interest and efforts at Lewis Research Center, a course entitled "Turbine Design and Application" was presented during 1968-69 as part of the In-House Graduate Study Program. The course was somewhat revised and again presented in 1972-73. Various aspects of turbine technology were covered including thermodynamic and fluid-dynamic concepts, fundamental turbine concepts, velocity diagrams, losses, blade aerodynamic design, blade cooling, mechanical design, operation, and performance. The notes written and used for the course have been revised and edited for publication. Such a publication can serve as a foundation for an introductory turbine course, a means for self-study, or a reference for selected topics. The first volume presented the material covering thermodynamic and fluid-dynamic concepts, fundamental turbine concepts, and velocity diagram design. This second volume presents the material related to blade aerodynamic design and turbine energy losses.

Arthur J Glassman↗

NASA NTRS1977

Some opportunities in teleoperated mining

Processes involved in remote control mining (fragmentation, material handling, ground and environmental control) are discussed with reference to longwall shear mining, the method which affords the greatest potential for the use of teleoperated systems. The breakup and haulage procedures are outlined, with attention to environmental control subsystems, i.e., noise and dust abatement. A description of a four-legged chock, attached to a section of a face conveyor and operated remotely, is presented.

Palowitch, E. R.↗

NASA NTRS1980

Effect of UV irradiation on evaporated ZnS films

Evaporated ZnS films used as a component in reflectance enhancing or decreasing multilayer coatings for mirrors, transparent optical materials, and vacuum UV reflecting optics, are investigated with reference to the reflectance loss under UV irradiation and the formation of ZnO as a result of the decomposition of ZnS in the presence of oxygen. Reflectance measurements over a broad wavelength range reveal that the UV induced reflectance losses are generally restricted to wavelengths shorter than 4000 A and are most severe in the vacuum UV region. After 134 hr of UV exposure initially polycrystalline film of 150-200 A thick is completely converted to amorphous ZnO. The results demonstrate that caution should be exercised in employing ZnS as the outer layer in an optical coating system designed for use in the UV and vacuum UV regions.

Hass, G.↗

NASA NTRS1981

A document describing shuttle considerations for the design of large space structures

A Shuttle user guide document to aid designers and analysis associated with large space structures projects is described. The format and contents are a compromise designed to satisfy the needs of several levels of users. Special features include checklists and references to source documents as a convenience to very knowledgeable readers. In addition, general, introductory and explanatory text, and art work are included for the reader less familiar with shuttle systems. Also, there are a subject index, glossary, list of acronyms, and many cross references. Throughout the document, there are suggested implications or references to the importance of the included orbiter interfaces material as it pertains to designing and planning large space structures projects. The content of the document is outlined. Shuttle payload accommodations and constraints, connections for orbiter construction fixtures, packaging, and construction space eometry are addressed.

Roebuck, J. A., Jr.↗

NASA NTRS1981

Langley's Space Shuttle Technology: A bibliography

This bibliography documents most of the major publications, research reports, journal articles, presentations, and contractor reports, which have been published since the inception of the Space Shuttle Technology Task Group at the NASA Langley Reseach Center on July 11, 1969. This research work was performed in house by the Center staff or under contract, monitored by the Center staff. The report is arranged according to method of publication: (1) NASA Formal Reports; (2) Contractor Reports; and (3) Articles and Conferences. Disciplines covered are in the areas of aerothermodynamics, structures, dynamics and aeroelasticity, environmental, and materials. The publications are listed without abstracts for quick reference and planning.

Champine, G. R.↗

NASA NTRS1982

Designing with figer-reinforced plastics (planar random composites)

The use of composite mechanics to predict the hygrothermomechanical behavior of planar random composites (PRC) is reviewed and described. These composites are usually made from chopped fiber reinforced resins (thermoplastics or thermosets). The hygrothermomechanical behavior includes mechanical properties, physical properties, thermal properties, fracture toughness, creep and creep rupture. Properties are presented in graphical form with sample calculations to illustrate their use. Concepts such as directional reinforcement and strip hybrids are described. Typical data that can be used for preliminary design for various PRCs are included. Several resins and molding compounds used to make PRCs are described briefly. Pertinent references are cited that cover analysis and design methods, materials, data, fabrication procedures and applications.

Chamis, C. C.↗

NASA NTRS1982

Thematic mapper flight model preshipment review data package. Volume 2, part B: Subsystem data

Summarized performance data are presented for the following major subsystems of the thematic mapper: the focal plane assembly, the radiative cooler, the radiative cooler door assembly, the top optical assembly, and the telescope assembly. Reference lists of the configurations status and of nonconforming material reports, failure reports, and requests for deviation/waiver are included.

Source record↗

NASA NTRS1983

The Mimas ghost revisited - An analysis of the electron flux and electron microsignatures observed in the vicinity of Mimas at Saturn

An analysis of the electron-absorption signature observed by the cosmic-ray system on Voyager 2 near the orbit of Mimas is presented. It is found that these observations cannot be explained as the absorption signature of Mimas. By combining Pioneer 11 and Voyager 2 measurements of the electron flux at Mimas's orbit (L = 3.1), an electron spectrum is found in which most of the flux above about 100 keV is concentrated near 1 to 3 MeV. This spectral form is qualitatively consistent with the bandpass filter model of Van Allen et al. (1980). The expected Mimas absorption signature is calculated from this spectrum neglecting radial diffusion. Since no Mimas absorption signature was observed in the inbound Voyager 2 data, a lower limit on the diffusion coefficient for MeV electrons at L = 3.1 of D greater than 10 to the -8th sq Saturn radii/sec is obtained. With a diffusion coefficient this large, both the Voyager 2 and the Pioneer 11 small-scale electron-absorption-signature observations in Mimas's orbit are enigmatic. Thus the mechanism for producing these signatures is referred to as the Mimas ghost. A cloud of material in orbit with Mimas may account for the observed electron signature if the cloud is at least 1-percent opaque to electrons across a region extending over a few hundred kilometers.

Chenette, D. L.↗

NASA NTRS1986

Diamondlike carbon - A bibliography of published papers and reports

A bibliography of references on investigations of diamond-like carbon (DLC) materials is presented. The list was developed over several years of active research and by computerized searches for the following keywords: diamondlike carbon, diamond-like carbon, hard carbon, i-carbon, A-C:H, and amorphous hydrogenated carbon. The bibliography has 241 citations, begins in 1956, includes an author index and was last updated in August 1985.

Woollam, J. A.↗

NASA NTRS1986

Effect of 15 MPa hydrogen on creep-rupture properties of iron-base superalloys

Six wrought alloys (A-286, Incoloy 800H, N-155, 19-9DL, 12RN72, and CG-27) and four cast alloys (XF-813, CRM-6D, HS-31, and SA-F11), candidate materials for use in Stirling engines, were evaluated with reference to creep-rupture characteristics in 15-MPa H2 at 705 and 925 C. An analysis of the test results indicates that hydrogen has no effect on the rupture life and the minimum creep rate of the alloys investigated. Rupture ductility in hydrogen is lower than in air, but the mode of fracture is not significantly affected.

Bhattacharyya, S.↗

NASA NTRS1990

LifeSat - Radiation research

Spaceflight crews will be exposed to levels of radiation which exceed those experienced on the ground. In order to reduce the uncertainty in the evaluation of risks it is necessary to validate the responses of biological systems in space under conditions which simulate exposure levels expected during exploration class missions. The LifeSat system provides the experimental capabilities to satisfy these goals. Specifically, LifeSat is capable of long duration flights of up to 60 days, is able to fly directly into trapped radiation belts and in circular or eccentric polar orbits, has the ability to provide artificial gravity and imposes fewer restrictions than the STS on the use of hazardous materials such as chemical fixatives. These features along with reference missions and experiments are discussed with respect to radiation research goals.

Nelson, Gregory A.↗

NASA NTRS1991

Vibration suppression using smart structures

The control of structures for vibration suppression is discussed in the context of using smart materials and structures. Here the use of smart structures refers to using embedded piezoelectric devices as both control actuators and sensors. Using embedded sensors and actuators allows great improvements in performance over traditional structures (both passive and active) for vibration suppression. The application of smart structures to three experimental flexible structures is presented. The first is a flexible beam, the second is a flexible beam undergoing slewing motion, the third is a ribbed antenna. A simple model of a piezoelectric actuator/sensor is presented. The equations of motion for each structure is presented. The control issues considered as those associated with multi-input, multi-output control, PID control and LQR control implementation. A modern control analysis illustrates the usefulness of smart structures for vibration suppression.

Garcia, Ephrahim↗

NASA NTRS1955

A survey of unclassified axial-flow-compressor literature

A survey of unclassified axial-flow-compressor literature is presented in the form of brief reviews of the methods, results, and conclusions of selected reports. The reports are organized into several main categories with subdivisions, and frequent references are made within the individual reviews to pertinent material elsewhere in the survey.

Herzig, Howard Z↗

NASA NTRS1999

Structured Course Objects in a Digital Library

We are developing an Undergraduate Digital Library Framework (UDLF) that will support creation/archiving of courses and reuse of existing course material to evolve courses. UDLF supports the publication of course materials for later instantiation for a specific offering and allows the addition of time-dependent and student-specific information and structures. Instructors and, depending on permissions, students can access the general course materials or the materials for a specific offering. We are building a reference implementation based on NCSTRL+, a digital library derived from NCSTRL. Digital objects in NCSTRL+ are called buckets, self-contained entities that carry their own methods for access and display. Current bucket implementations have a two level structure of packages and elements. This is not a rich enough structure for course objects in UDLF. Typically, courses can only be modeled as a multilevel hierarchy and among different courses, both the syntax and semantics of terms may vary. Therefore, we need a mechanism to define, within a particular library, course models, their constituent objects, and the associated semantics in a flexible, extensible way. In this paper, we describe our approach to define and implement these multilayered course objects. We use XML technology to emulate complex data structures within the NCSTRL+ buckets. We have developed authoring and browsing tools to manipulate these course objects. In our current implementation a user downloading an XML based course bucket also downloads the XML-aware tools: an applet that enables the user to edit or browse the bucket. We claim that XML provides an effective means to represent multi-level structure of a course bucket.

Maly, K.↗

NASA NTRS2009

The Lunar Regolith

A thick layer of regolith, fragmental and unconsolidated rock material, covers the entire lunar surface. This layer is the result of the continuous impact of meteoroids large and small and the steady bombardment of charged particles from the sun and stars. The regolith is generally about 4-5 m thick in mare regions and 10-15 m in highland areas (McKay et al., 1991) and contains all sizes of material from large boulders to sub-micron dust particles. Below the regolith is a region of large blocks of material, large-scale ejecta and brecciated bedrock, often referred to as the "megaregolith". Lunar soil is a term often used interchangeably with regolith, however, soil is defined as the subcentimeter fraction of the regolith (in practice though, soil generally refers to the submillimeter fraction of the regolith). Lunar dust has been defined in many ways by different researchers, but generally refers to only the very finest fractions of the soil, less than approx.10 or 20 microns. Lunar soil can be a misleading term, as lunar "soil" bears little in common with terrestrial soils. Lunar soil contains no organic matter and is not formed through biologic or chemical means as terrestrial soils are, but strictly through mechanical comminution from meteoroids and interaction with the solar wind and other energetic particles. Lunar soils are also not exposed to the wind and water that shapes the Earth. As a consequence, in contrast to terrestrial soils, lunar soils are not sorted in any way, by size, shape, or chemistry. Finally, without wind and water to wear down the edges, lunar soil grains tend to be sharp with fresh fractured surfaces.

Noble, Sarah↗