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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Verifiable Security Templates for Hardware

High-level synthesis (HLS) research generally focuses on transferring "software engineering virtues" (e.g., modularity, abstraction, extensibility, etc.) to hardware development with the ultimate goal of making hardware development as agile as software development. And recent HLS research has focused on transferring ideas and techniques from high assurance software formal methods to hardware development. Just as it has introduced software engineering virtues, we believe HLS can also become a vector for adapting software formal methods to the challenge of high assurance security in hardware. This paper introduces the Device Calculus and its mechanization in the Agda proof checking system. The Device Calculus is a starting point for exploring the formal methods and security of high-level synthesis flows. We illustrate the Device Calculus with a number of examples of formally verifiable security templates-i.e., functions in the Device Calculus that express common security structures at a high-level of abstraction.

Harrison, Bill↗
DOE OSTI2021

Templating Functional Materials Using Self-Assembled Block Copolymer Thin-Film for Nanodevices

The nanomorphologies and nanoarchitectures that can be synthesized using block copolymer (BCP) thin-film self-assembly have inspired a variety of new applications, which offer various advantages, such as, small device footprint, low operational power and enhanced device performance. Imperative for these applications, however, is the ability to transform these small polymeric patterns into useful inorganic structures. BCP-templated inorganic nanostructures have shown the potential for use as active materials in various electronic device applications, including, field-effect transistors, photodetectors, gas sensors and many more. This article reviews various strategies that have been implemented in the past decade to fabricate devices at nanoscale using block copolymer thin films.

Subramanian, Ashwanth↗
DOE OSTI2025

Block Copolymer-Templated Synthesis of Fe–Ni–Co-Modified Nanoporous Alumina Films

Despite intense interest in the catalytic potential of transition metal oxide heterostructures, originating from their large surface area and tunable chemistry, the fabrication of well-defined multicomponent oxide coatings with controlled architectures remains challenging. Here, we demonstrate a simple and effective swelling-assisted sequential infiltration synthesis (SIS) strategy to fabricate hierarchically porous multicomponent metal-oxide electrocatalysts with tunable bimetallic composition. A combination of solution-based infiltration (SBI) of transition metals, iron (Fe), nickel (Ni), and cobalt (Co), into a block copolymer (PS73-b-P4VP28) template, followed by vapor-phase infiltration of alumina using sequential infiltration synthesis (SIS), was employed to synthesize porous, robust, conformal and transparent multicomponent metal-oxide coatings like Fe/AlO x , Fe+Ni/AlO x , and Fe+Co/AlO x . Electrochemical assessments for the oxygen evolution reaction (OER) in a 0.1 M KOH electrolyte demonstrated that the Fe+Ni/AlO x composite exhibited markedly superior catalytic activity, achieving an impressive onset potential of 1.41 V and a peak current density of 3.29 mA/cm 2 . This superior activity reflects the well-known synergistic effect of alloying transition metals with a trace of Fe, which facilitates OER kinetics. Overall, our approach offers a versatile and scalable path towards the design of stable and efficient catalysts with tunable nanostructures, opening new possibilities for a wide range of electrochemical energy applications.

conformal films↗
DOE OSTI2025

Legacy Survey of Space and Time Data Preview 1: template_coadd dataset type

The Legacy Survey of Space and Time Data Preview 1 (DP1) is the first release of data from the NSF-DOE Vera C. Rubin Observatory. It consists of raw and calibrated single-epoch images, co-adds, difference images, detection catalogs, and other derived data products. DP1 is based on 1792 science-grade optical/near-infrared exposures acquired over 48 distinct nights by the Rubin Commissioning Camera, LSSTComCam, on the Simonyi Survey Telescope at the Summit Facility on Cerro Pachón, Chile during the first on-sky commissioning campaign in late 2024. DP1 covers a total of approximately 15 sq. deg. over seven roughly equally-sized non-contiguous fields, each independently observed in six broad photometric bands, ugrizy, spanning a range of stellar densities and latitudes and overlapping with external reference datasets. This dataset is a subset of the full data release consisting of the template_coadd dataset type. These are the combination of processed images with the best seeing, for a patch of sky and for each of the six LSST filters. Used to create difference images. This release contains 2,730 datasets of this type.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1964

Built-in templates speed up process for making accurate models

From accurate scale drawings of a model, photographic negatives of the cross sections are printed on thin sheets of aluminum. These cross-section images are cut out and mounted, and mahogany blocks placed between them. The wood can be worked down using the aluminum as a built-in template.

Source record↗
NASA NTRS1977

The origin of biological macromolecules on the earth. The hypothesis of inorganic template

Studies about the origin of life are reviewed. The nonrandom organization of organelles is discussed from a structural and functional point of view. After postulating that the origin of biomacromolecules was not a random event, the paper develops the hypothesis that polypeptides and polynucleotides were formed on an inorganic template. Only information-containing structures can pass natural selection and develop through evolution.

Lu, T. S.↗
NASA NTRS1979

Plug and drill template

Device installs plugs and then drills them after sandwich face sheets are in place. Template guides drill bit into center of each concealed plug thereby saving considerable time and fostering weight reduction with usage of smaller plugs.

Orella, S.↗
NASA NTRS1979

Template-directed synthesis of oligoadenylates catalyzed by Pb/2+/ ions

The Pb(2+) ion is an effective catalyst for the template-directed condensation of ImpA on poly(U). This reaction generates up to 35% of oligomers 5 or more units long. Furthermore, the product is predominantly 3'-5'-linked (75%) unlike that from the uncatalyzed reaction which is more than 90% 2'-5'-linked. The significance of metal-ion catalysis for prebiotic polynucleotide formation is discussed.

Sleeper, H. L.↗
NASA NTRS1980

Template-directed synthesis and selective adsorption of oligoadenylates in hydroxyapatite

Polyuridylic acid is adsorbed completely from aqueous solution by hydroxyapatite under conditions that permit template-directed synthesis of oligoadenylates in free solution. The yield of oligoadenylates is enhanced to almost the same extent by poly(U) in the presence or the absence of hydroxyapatite. Under very similar conditions small quantities of hydroxyapatite adsorb higher-molecular-weight oligoadenylates selectively from a mixture of oligomers. On the basis of these results a mechanism for prebiotic oligonucleotide formation is proposed in which selective adsorption on hydroxyapatite or some other immobilized anion-exchanging material plays a major role. Monomers are released from the surface for reactivation, while oligomers are retained in a protected environment by adsorption to the apatite surface.

Gibbs, D.↗
NASA NTRS1982

Template directed reactions of 2-aminoadenylic acid derivatives

The template-directed oligomerization of activated derivatives of 2-aminoadenylic acid (paA) on polyuridylic acid (poly(U)) in aqueous buffers was studied. The reaction differs from that of adenylic acid (pA) under identical conditions, in that only di- and tri-nucleotides are observed as substantial products rather than a longer sequence of oligomers. The reaction of paA also differs from that of pA in that it does not require Mg (2+), and is less susceptible to increased temperature. The relevance of these observations to the chemical evolution of polynucleotide replication is discussed. Improved syntheses of paA and its diphosphate are reported.

Webb, T. R.↗
NASA NTRS1985

Template-directed polynucleotide synthesis on mineral surfaces

Ferric hydroxide, a plausible prebiotic material, strongly adsorbs polynucleotides. It is shown that adsorption on ferric hydroxide and on several other minerals has no effect, under the conditions studied, on the template-directed oligomerization of guanylic acid on polycytidylic acid.

Schwartz, A. W.↗
NASA NTRS1986

Did template-directed nucleation precede molecular replication?

It is proposed that mononucleotides incorporated into the surfaces of microcrystals of inorganic phosphates such as hydroxyapatite can act as templates to assemble complementary mononucleotides from solution, and that the phosphate groups of the assembled nucleotides can facilitate nucleation of a second hydroxyapatite crystal. This would provide a mechanism of replication that is subject to natural selection. The possible role of a replicating system of this kind in the origins of life on the earth is discussed.

Orgel, Leslie E.↗
NASA NTRS1988

Template-directed oligomerization of 3-isoadenosine 5'-phosphate

Template-directed oligomerization of an activated derivative of 3-isoadenosine 5'-phosphate (piA) on polyuridylic acid was studied. The reaction of ImpiA is more efficient than the corresponding reaction of ImpA, and produces 3'-5'-linked oligomers while the reaction of ImpA gives only 2'-5'-linked oligomers. The base pairing between piA and poly(U) in this system is probably of the Hoogsteen type (involving the 6-amino group and N7 of 3-isoadenosine) rather than of the Watson-Crick type.

Hill, Aubrey R., Jr.↗
NASA NTRS1989

Template-directed oligomerization catalyzed by a polynucleotide analog

A pyrophosphate-linked analog of polycytidylic acid has been synthesized and shown to catalyze the oligomerization of the complementary monomer 2'-deoxyguanosine 3',5'-bisphosphoimidazolide. Analogs of polynucleotides are of interest in studies of the origins of life as possible precursors of the first RNA molecules. These results demonstrate that such molecules are capable of serving as templates for further synthesis.

Visscher, J.↗
NASA NTRS1989

Oligomerization of deoxynucleoside-biphosphate dimers - Template and linkage specificity

The oligomerization of the activated 3-prime-5-prime pyrophosphate-linked dimer, pdAppdAp, is presently noted to be selectively favored by a poly(U) template over the 3-prime-3-prime and 5-prime-5-prime linked dimers. Both overall yields and the production of the longest oligomers were markedly stimulated by poly(U)'s presence; in its absence, the 5-prime-5-prime linked dimer became the most reactive, yielding chains of the order of 60 monomer-unit lengths. Remarkable self-organization properties are noted for the 5-prime-5-prime dimer of pdAp.

Visscher, J.↗
NASA NTRS1990

Template-directed oligomerization of 5-prime-deoxy 5-nucleosideacetic acid derivatives

5-prime-deoxy 5-nucleosideacetic acids H-II are isostructural analogs of nucleotides with a carboxylate group in the place of the 5-prime-phosphate group. In this work, their oligomerization in aqueous solution was studied using a water-soluble carbodiimide as the condensing agent in the presence or absence of an appropriate polynucleotide template. Condensation of adenylic acid analogs IIa, IIIa, and Va in the presence of polyuridylic acid were found to be the most efficient reactions. Cyclization of the activated monomers to lactones and the insolubility of the oligomers in aqueous solution were found to be obstacles to the efficient formation of long oligomers.

Harada, Kazuo↗
NASA NTRS1989

Magnesium ion catalyzed P-N bond hydrolysis in imidazolide-activated nucleotides - Relevance to template-directed synthesis of polynucleotides

Results are presented from a detailed study of the P-N bond hydrolysis in guanosine 5-prime-monophosphate 2-methylimidazolide (2-MeImpG) and in guanosine 5-prime-imidazolide (ImpG) in the presence of 0-0.50 M Mg(2+). Pseudo-first-order rate constants of these compounds were obtained as a function of Mg(2+) concentration, for pH values between 6 and 10 and 37 C. It was found that Mg(2+) catalysis was most effective at pH 10, where a 15-fold increase in hydrolysis was achieved in 0.02 M Mg; at 0.2 M, a 115-fold increase was observed. Implication of these results for the mechanism of template-directed oligomerization is discussed.

Kanavarioti, Anastassia↗