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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 1,747 records · Page 97
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

3D Hybrid Plasmonic Framework with Au Nanopillars Embedded in Nitride Multilayers Integrated on Si

Integration of nanoscale photonic and plasmonic components on Si substrates is a critical step toward Si-based integrated nanophotonic devices. Herein, a set of unique complex 3D metamaterials with intercalated nanolayered and nanopillar structures with tunable plasmonic and optical properties on Si substrates is designed. More specifically, the 3D metamaterials combine metal (Au) nanopillars and alternating metal-nitride (Au-TiN and Au-TaN) nanolayers, epitaxially grown on Si substrates. The ultrafine Au nanopillars ( d ≈ 3 nm) continuously grow throughout all the nanolayers with high epitaxial quality. Novel optical properties, such as highly anisotropic optical property, high absorbance covering the entire visible spectrum regime, and hyperbolic property in the visible regime, are demonstrated. Furthermore, a waveguide based on a silicon nitride (Si 3 N 4 ) ridge with a multilayer structure is successfully fabricated. The demonstration of 3D nanoscale metamaterial design integrated on Si opens up a new route toward tunable metamaterials nanostructure designs with versatile material selection for various optical components in Si integrated photonics.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Synthesis of wafer-scale SWCNT forests with remarkably invariant structural properties in a bulk-diffusion-controlled kinetic regime

Robust synthesis of vertically aligned carbon nanotubes (VACNT) at large scale is required to accelerate deployment of numerous cutting-edge devices to emerging commercial applications. To address this need, this work demonstrates that the structural characteristics of single-walled CNTs (SWCNTs) produced in a growth regime dominated by bulk diffusion of the gaseous carbon precursor are remarkably invariant over a broad range of process conditions (precursor concentration increased up to 30-fold, catalyst substrate area from 1 cm 2 to 180 cm 2 , growth pressure from 20 to 790 mbar, and gas flowrates up to 8-fold). A simple growth kinetics model is derived that accounts for both reactant bulk diffusion and competing byproduct formation in the presence of excess hydrogen, which quantitatively reproduces the experimental data in the entire isothermal parameter space. The model enables critical predictions for process scale-up optimization including a potential 6-fold increase in CNT production rate, a ~90% carbon conversion efficiency in select conditions, and elimination of reaction rate decay observed at high pressures by using a hydrogen-free growth environment. This model-guided opportunity to substantially improve synthesis throughput and efficiency, in conjunction with the remarkably invariant CNT properties, is appealing for reliable VACNT device fabrication at both small and industrial scales.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Biphenyl dicarboxylates from ethene and bifuran dimethyl esters

The substrate scope of the Diels-Alder-Dehydration reaction was expanded to the deactivated bifuran structure. Dimethyl biphenyl-4,4'-dicarboxylate (1) and methyl 5- [4-(methoxycarbonyl)phenyl]-2-furoate (2) were synthesized from dimethyl 2,2'-bifuran-5,5'-dicarboxylate (3) via metal-triflate-catalyzed Diels-Alder-Dehydration reaction with ethene. A 31% yield of (1) was obtained using Sc(OTf)3 catalyst, and a 76.6% yield of (2) was obtained using La(OTf)3 catalyst under moderate reaction conditions. This approach is inherently selective to the 4,4'-dicarboxylates, and bypasses the methyl-group oxidation step of the dimethyl-biphenyl route.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1982

Collimated beam manifold with the number of output beams variable at a given output angle

An optical manifold is described which transforms a collimated beam, such as a laser beam, into a plurality of parallel beams having uniform intensity or having a desired intensity ratio. The manifold comprises an optical substrate coated on its rear surface with a fully reflective layer and on its front surface with a partially reflecting layer having a reflectivity gradient. An input collimated beam entering the rear surface and impinging on the front surface is reflected, multiply between the front and rear surfaces producing a plurality of parallel beams that emerge from the front surface. The intensities of the emerging beams have a relationship that depends on the reflectivity of the front surface at the points where the beams emerge. By properly selecting the reflectivity gradient, the emerging beams have uniform intensity or a desired intensity ratio.

Campbell, C. W.↗
NASA NTRS2005

Bio-Nanobattery Development and Characterization

A bio-nanobattery is an electrical energy storage device that utilizes organic materials and processes on an atomic, or nanometer-scale. The bio-nanobattery under development at NASA s Langley Research Center provides new capabilities for electrical power generation, storage, and distribution as compared to conventional power storage systems. Most currently available electronic systems and devices rely on a single, centralized power source to supply electrical power to a specified location in the circuit. As electronic devices and associated components continue to shrink in size towards the nanometer-scale, a single centralized power source becomes impractical. Small systems, such as these, will require distributed power elements to reduce Joule heating, to minimize wiring quantities, and to allow autonomous operation of the various functions performed by the circuit. Our research involves the development and characterization of a bio-nanobattery using ferritins reconstituted with both an iron core (Fe-ferritin) and a cobalt core (Co-ferritin). Synthesis and characterization of the Co-ferritin and Fe-ferritin electrodes were performed, including reducing capability and the half-cell electrical potentials. Electrical output of nearly 0.5 V for the battery cell was measured. Ferritin utilizing other metallic cores were also considered to increase the overall electrical output. Two dimensional ferritin arrays were produced on various substrates to demonstrate the feasibility of a thin-film nano-scaled power storage system for distributed power storage applications. The bio-nanobattery will be ideal for nanometerscaled electronic applications, due to the small size, high energy density, and flexible thin-film structure. A five-cell demonstration article was produced for concept verification and bio-nanobattery characterization. Challenges to be addressed include the development of a multi-layered thin-film, increasing the energy density, dry-cell bionanobattery development, and selection of ferritin core materials to allow the broadest range of applications. The potential applications for the distributed power system include autonomously-operating intelligent chips, flexible thin-film electronic circuits, nanoelectromechanical systems (NEMS), ultra-high density data storage devices, nanoelectromagnetics, quantum electronic devices, biochips, nanorobots for medical applications and mechanical nano-fabrication, etc.

King, Glen C.↗
DOE OSTI2021

Production of polyhydroxy alkanoates with a defined composition from an unrelated carbon source

Cells and methods for producing polyhydroxyalkanoates. The cells comprise one or more recombinant genes selected from an R-specific enoyl-CoA hydratase gene, a PHA polymerase gene, a thioesterase gene, and an acyl-CoA-synthetase gene. The cells further have one or more genes functionally deleted. The functionally deleted genes include such genes as an enoyl-CoA hydratase gene, a 3-hydroxyacyl-CoA dehydrogenase, and a 3-ketoacyl-CoA thiolase gene. The recombinant cells are capable of using producing polyhydroxyalkanoates with a high proportion of monomers having the same carbon length from non-lipid substrates, such as carbohydrates.

Pfleger, Brian Frederick↗
NASA NTRS1999

Metallurgical Evaluations of Depainting Processes on Aluminum Substrate

In December 1993, the Environmental Protection Agency (EPA) Emission Standards Division and the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) signed an Interagency Agreement (IA) initiating a task force for the technical assessment of alternative technologies for aerospace depainting operations. The United States Air Force (USAF) joined the task force in 1994. The mandates of the task force were: (1) To identify available alternative depainting systems that do not rely on methylene chloride or other ozone-depleting, chlorinated, and volatile organic carbon solvents. (2) To determine the viability, applicability, and pollution prevention potential of each identified alternative. (3) To address issues of safety, environmental impact, reliability, and maintainability. Through a Technical Implementation Committee (TIC), the task force selected and evaluated eight alternative paint stripping technologies: chemical stripping, carbon dioxide (CO2) blasting, xenon flashlamp and CO2 coatings removal (FLASHJET(R)), CO2 laser stripping, plastic media blasting (PMB), sodium bicarbonate wet stripping, high-pressure water blasting (WaterJet), and wheat starch abrasive blasting (Enviro-Strip(R)). (The CO2 blasting study was discontinued after the first depainting sequence.) This final report presents the results of the Joint EPA/NASA/USAF Interagency Depainting Study. Significant topics include: (1) Final depainting sequence data for the chemical stripping, PMB, sodium bicarbonate wet stripping, and WaterJet processes. (2) Strip rates for all eight technologies. (3) Sequential comparisons of surface roughness measurements for the seven viable depainting technologies. (4) Chronological reviews of and lessons learned in the conduct of all eight technologies. (5) An analysis of the surface roughness trends for each of the seven technologies. (6) Metallurgic evaluations of panels Summaries of corrosion and hydrogen embrittlement evaluations of chemical stripping panels, detailed descriptions of which appear in previous reports. Because the requirements for alternative systems are diverse, as are initial setup, training, and on-going operational considerations, this study does not recommend a particular product or process. Users of this study will draw their own conclusions from the data presented herein.

McGill, Preston↗
DOE OSTI2023

Reductive amination cascades in cell‐free and resting whole cell formats for valorization of lignin deconstruction products

Abstract The selective introduction of amine groups within deconstruction products of lignin could provide an avenue for valorizing waste biomass while achieving a green synthesis of industrially relevant building blocks from sustainable sources. Here, we built and characterized enzyme cascades that create aldehydes and subsequently primary amines from diverse lignin‐derived carboxylic acids using a carboxylic acid reductase (CAR) and an ω‐transaminase (TA). Unlike previous studies that have paired CAR and TA enzymes, here we examine multiple homologs of each of these enzymes and a broader set of candidate substrates. In addition, we compare the performance of these systems in cell‐free and resting whole‐cell biocatalysis formats using the conversion of vanillate to vanillyl amine as model chemistry. We also demonstrate that resting whole cells can be recycled for multiple batch reactions. We used the knowledge gained from this study to produce several amines from carboxylic acid precursors using one‐pot biocatalytic reactions, several of which we report for the first time. These results expand our knowledge of these industrially relevant enzyme families to new substrates and contexts for environmentally friendly and potentially low‐cost synthesis of diverse aryl aldehydes and amines.

Biotechnology & Applied Microbiology↗
DOE OSTI2016

An in-depth understanding of biomass recalcitrance using natural poplar variants as the feedstock

Here, in an effort to better understand the biomass recalcitrance, six natural poplar variants were selected as feedstocks based on previous sugar release analysis. Compositional analysis and physicochemical characterizations of these poplars were performed and the correlations between these physicochemical properties and enzymatic hydrolysis yield were investigated. Gel permeation chromatography (GPC) and 13 C solid state NMR were used to determine the degree of polymerization (DP) and crystallinity index (CrI) of cellulose, and the results along with the sugar release study indicated that cellulose DP likely played a more important role in enzymatic hydrolysis. Simons’ stain revealed that the accessible surface area of substrate significantly varied among these variants from 17.3 to 33.2 mg g$–1\atop{biomass}$ as reflected by dye adsorption, and cellulose accessibility was shown as one of the major factors governing substrates digestibility. HSQC and 31 P NMR analysis detailed the structural features of poplar lignin variants. Overall, cellulose relevant factors appeared to have a stronger correlation with glucose release, if any, than lignin structural features. Lignin structural features, such as a phenolic hydroxyl group and the ratio of syringyl and guaiacyl (S/G), were found to have a more convincing impact on xylose release. Low lignin content, low cellulose DP, and high cellulose accessibility generally favor enzymatic hydrolysis; however, recalcitrance cannot be simply judged on any single substrate factor.

09 BIOMASS FUELS↗
DOE OSTI2018

Synthesis, Processing and Properties of Calcium- and Nickel-Doped Yttrium Chromates(III) Y{sub 0.8}Ca{sub 0.2}Cr{sub 1−x}Ni{sub x}O{sub 3} (x = 0-0.3) and Studies on Their Potential Application as Coatings for SOFC Interconnects

In the present study, a calcium- and nickel-doped yttrium chromates (YCCN)-based, conductive–protective layers for metallic interconnects used in the intermediate-temperature solid oxide fuel cells (IT-SOFCs) were investigated. Synthesis of Y{sub 0.8}Ca{sub 0.2}Cr{sub 1−x}Ni{sub x}O{sub 3} (x = 0; 0.15 and 0.3) powders was performed using a wet chemistry method with two different complexing agents: ethylenediaminetetraacetic acid and glycine. Based on the result of thermal analysis of obtained precursors, optimal conditions of the calcination process were determined. Powders were then milled, compacted and sintered at different temperatures using free sintering method, into series of dense, polycrystalline sinters. The use of glycine precursor allowed obtaining a single-phase material in all cases. Based on the electrical and sintering properties, the Y{sub 0.8}Ca{sub 0.2}Cr{sub 0.85}Ni{sub 0.15}O{sub 3} material was selected for further studies. It was deposited using cost-effective screen-printing method on the Crofer 22APU ferritic stainless steel. To investigate properties and suitability of the resulting layer/steel system for IT-SOFCs applications, the high-temperature, dual-atmosphere studies were carried out for the first time for ceramic/metallic system, in conditions as close as possible to actual working conditions of the fuel cell. The layer exhibited high stability and good protective properties. The area-specific resistance of the studied ceramic layer/metallic substrate composite was determined, with the obtained value of 0.0366 Ω cm{sup 2} being within the arbitrary limit set for these materials (0.1 Ω cm{sup 2}). The results show that the investigated materials are suitable for the projected application.

36 MATERIALS SCIENCE↗
DOE OSTI2025

High-current-density electrosynthesis of formate from captured CO 2 solution by MOF-derived bismuth nanosheets

Greenhouse gas emissions present a significant challenge to humanity, and utilizing renewable electricity to convert emitted CO 2 into value-added products offers a promising solution; however, traditional CO 2 capture and regeneration processes remain energy-intensive, restricting the overall system efficiency and decarbonization efficacy. In this study, an advanced direct reduction of captured CO 2 with large current densities for formate electrosynthesis was demonstrated without the need for CO 2 regeneration or compression. The bismuth nanosheet (DRM-BiNS) was synthesized by direct reduction of a Bi-based MOF, representing a new class of catalytic materials with a large surface area and interconnected pores, suitable for the direct reduction of captured CO 2 . By seamlessly combining experimentation and simulation, insights into the structure-parameter-performance relation were acquired in a flow cell setting, including critical membrane-electrode distance, cell orientation, and pumping flow rate. Important flow-cell components, such as catholyte volume, electrode substrate, membrane choice, and ionomer type, were also carefully examined to enhance the cell performance. In sharp contrast to prior studies limited to current densities below 20 mA/cm 2 in bicarbonate-based captured CO 2 solutions, this work demonstrates a remarkable current density of 300 mA/cm 2 with an FE to formate comparable to the case with gas-fed CO 2 reduction. Moreover, the process sustained an FE above 50% at a high current density of 500 mA/cm 2 . The DRM-BiNS catalyst exhibited outstanding selectivity, activity, and stability, significantly outperforming oxide-derived bismuth nanosheets (OD-BiNS) in captured CO 2 reduction. Furthermore, these findings offer critical insights into the development of sustainable and scalable CO 2 utilization technologies.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRSDate not supplied

Metallic Environmentally Resistant Coating Rapid Innovation Initiative

Lightweight alloys such as aluminum (Al) and titanium (Ti) are often specified for space systems to minimize mass while maintaining structural integrity [1,2]. Such alloys however, have poor tribological response (high friction and wear), especially in extreme space environments, which becomes worse with the additional presence of lunar regolith. This leads to short lifetimes and premature failures that will ultimately limit long term operations on the lunar surface [2]. This project is addressing this technology gap by developing advanced wear- and radiation-resistant coatings for lightweight parts to extend the life-time and sustainability of both lunar and Martian assets. Ceramics were considered for their high wear resistance, but were rejected because of their low fracture toughness, which would be especially problematic for structural components. The novel and existing coating technologies and deposition methods are being tested in this project. The coating materials are Boron Nitride-Aluminum (BN-Al), Nickle Titanium (NiTi), Aluminum Oxide (AlO3), Ti64 with hBN at 2 and 10 vol percent (Ti-2vol%hBN and Ti-10vol%hBN), and the deposition techniques are high pressure cold-spray (CS) and ambient and vacuum plasma-spray (APS and VPS) [3,4,5]. BN-Al, NiTi, Ti-2vol%hBN, and Ti-10vol%hBN were applied with all three deposition techniques, and AlO3 was applied only using the APS deposition technique. A tungstenite (WS2) film was applied to the NiTi VPS coating. The coating and deposition technique configurations are being tested against several key end-use performance parameters. The parameters include the capabilities of the coatings under wear environments such as regolith simulant, thermal cycling from high (120°C) to cryogenic (-173°C), high vacuum (~10-7 torr), and pre- and post-exposure to ionizing particle radiation. Wear tests include pin on disk, three-body abrasion, and surface erosion by high velocity regolith impacts. The initial down selection is being performed using on virgin and environmental exposure samples using pin on disk and three body abrasion wear tests. From preliminary assessment of this testing, a few configurations were eliminated. Ti-10vol%hBN could not be applied using CS application and NiTi could not be applied using APS or CS application so these configurations did not get tested. Early pin on disk wear tests showed poor wear performance of BN-Al so this coating was eliminated early in the testing process. AlO3 on Al substrate did not survive thermal cycling, but wear testing is continuing for AlO3 on Ti substrate. A more detailed analysis is being con-ducted to further reduce the number of configuration for phase II and III. Phase II testing will include conventionally and additively manufactured substrates with surface erosion testing. In phase III, the coatings will be applied to three mechanism types: channel and slot, ball and socket, and a hinge joint. Each will demonstrate a different type of wear incidence. The mechanisms and their base materials are of direct interest to the end users and infusion points: the Human Landing System (HLS) and the Lunar Surface Innovation Initiative (sustained lunar surface operations). The technology development project is based out of Marshall Space Flight Center, has partnered with Florida International University (Miami, FL) and Plasma Processes (Huntsville, Al), and is supported by a group of NASA mentors from different centers.

dust mitigation↗
DOE OSTI2019

Passive radiative cooling of a body

A metallic waveguide tuned to an infrared region of interest provides spectral and spatial control over emitted/absorbed thermal radiation. The ratio of the depth of the waveguide to the smallest lateral dimension thereof is such that that the lateral dimension provides spectral selectivity and that the waveguide is deep enough for a fixed lateral dimension to establish directionality but is not so deep that it incurs severe ohmic losses. A panel with an array of such waveguides directs thermal radiation from a body in a specific direction and with a spectral response that is the result of the physical dimensions of the individual waveguides that make up the waveguide array and the arrangement of the waveguides in the array. The waveguide axis may be obliquely oriented with respect to the substrate normal so as to impart non-normal directionality to the emitted radiation with respect to the substrate normal surface.

42 ENGINEERING↗
DOE OSTI2019

Photocatalytic behaviors of epitaxial BiVO4 (010) thin films

Photocatalytic studies performed on well-defined epitaxial thin films and heterostructures allow the direct investigation of crystallographic-dependent reactivity, and can provide fundamental insights into the reaction mechanisms. In this work, we show that phase-pure, monoclinic BiVO4 nanoislands with a truncated pyramid shape displaying {110} sidewalls can be grown on (001)-oriented yttria-stabilized zirconia (YSZ) substrates with an epitaxial relationship of BiVO4(010)[001] // YSZ(001)[100]. The resulting nanostructures show a strong size-dependent mass-normalized photocatalytic activity, with highly dispersed nanoislands at low coverage being the most active for rhodamine B degradation. Different from studies performed on faceted nanocrystals, when BiVO4 nanostructured films react with Pb(NO3)2 in aqueous solution with and without NaIO3 under full arc irradiation of Xe lamp, nanoparticles were found on the (110) and (010) surface of BiVO4, respectively, indicating that the cocatalyst could be selectively deposition on different facets of the same photocatalayst.

Li, Guoqiang↗
DOE OSTI2026

Electrochemical carbon deposition from CO 2 in molten carbonates: substrate-dependent growth

Electrochemical carbon deposition from molten carbonate salts using inert electrodes and no additional catalyst is systematically examined. At sufficiently cathodic potentials, carbon formation occurs within 30 min and transitions from substrate-dependent nucleation to carbon-on-carbon growth. Although deposits formed on either mild-steel or graphite cathodes exhibit comparable thicknesses and salt contents, their macrostructures differ, reflecting differences in early-stage growth rates and surface chemistry. Characterization by ICP-OES, Raman spectroscopy, SEM/EDS, synchrotron powder X-ray diffraction, and C K-edge X-ray absorption near edge structure reveals that the as-deposited carbon is predominantly disordered sp 2 -bonded material. However, post-treatment reveals latent turbostratic ordering in select samples, indicating that short-range order is established during deposition but is obscured by an entrained electrolyte and kinetically formed amorphous phases. No anode-derived contamination is detected, and carbon grown on graphite cathodes shows minimal metallic impurities. These results clarify the role of cathode surface chemistry and provide pathways for controlling electrode-derived impurity incorporation and carbon structure in catalyst-free molten carbonate systems.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Pangenomes suggest ecological-evolutionary responses to experimental soil warming

ABSTRACT Below-ground carbon transformations that contribute to healthy soils represent a natural climate change mitigation, but newly acquired traits adaptive to climate stress may alter microbial feedback mechanisms. To better define microbial evolutionary responses to long-term climate warming, we study microorganisms from an ongoing in situ soil warming experiment where, for over three decades, temperate forest soils are continuously heated at 5°C above ambient. We hypothesize that across generations of chronic warming, genomic signatures within diverse bacterial lineages reflect adaptations related to growth and carbon utilization. From our bacterial culture collection isolated from experimental heated and control plots, we sequenced genomes representing dominant taxa sensitive to warming, including lineages of Actinobacteria, Alphaproteobacteria, and Betaproteobacteria. We investigated genomic attributes and functional gene content to identify signatures of adaptation. Comparative pangenomics revealed accessory gene clusters related to central metabolism, competition, and carbon substrate degradation, with few functional annotations explicitly associated with long-term warming. Trends in functional gene patterns suggest genomes from heated plots were relatively enriched in central carbohydrate and nitrogen metabolism pathways, while genomes from control plots were relatively enriched in amino acid and fatty acid metabolism pathways. We observed that genomes from heated plots had less codon bias, suggesting potential adaptive traits related to growth or growth efficiency. Codon usage bias varied for organisms with similar 16S rrn operon copy number, suggesting that these organisms experience different selective pressures on growth efficiency. Our work suggests the emergence of lineage-specific trends as well as common ecological-evolutionary microbial responses to climate change. IMPORTANCE Anthropogenic climate change threatens soil ecosystem health in part by altering below-ground carbon cycling carried out by microbes. Microbial evolutionary responses are often overshadowed by community-level ecological responses, but adaptive responses represent potential changes in traits and functional potential that may alter ecosystem function. We predict that microbes are adapting to climate change stressors like soil warming. To test this, we analyzed the genomes of bacteria from a soil warming experiment where soil plots have been experimentally heated 5°C above ambient for over 30 years. While genomic attributes were unchanged by long-term warming, we observed trends in functional gene content related to carbon and nitrogen usage and genomic indicators of growth efficiency. These responses may represent new parameters in how soil ecosystems feedback to the climate system.

Choudoir, Mallory J. (ORCID:0000000291175150)↗
NASA NTRS1993

LUTE primary mirror materials and design study report

The major objective of the Lunar Ultraviolet Telescope Experiment (LUTE) Primary Mirror Materials and Design Study is to investigate the feasibility of the LUTE telescope primary mirror. A systematic approach to accomplish this key goal was taken by first understanding the optical, thermal, and structural requirements and then deriving the critical primary mirror-level requirements for ground testing, launch, and lunar operations. After summarizing the results in those requirements which drove the selection of material and the design for the primary mirror are discussed. Most important of these are the optical design which was assumed to be the MSFC baseline (i.e. 3 mirror optical system), telescope wavefront error (WFE) allocations, the telescope weight budget, and the LUTE operational temperature ranges. Mechanical load levels, reflectance and microroughness issues, and options for the LUTE metering structure were discussed and an outline for the LUTE telescope sub-system design specification was initiated. The primary mirror analysis and results are presented. The six material substrate candidates are discussed and four distinct mirror geometries which are considered are shown. With these materials and configurations together with varying the location of the mirror support points, a total of 42 possible primary mirror designs resulted. The polishability of each substrate candidate was investigated and a usage history of 0.5 meter and larger precision cryogenic mirrors (the operational low end LUTE temperature of 60 K is the reason we feel a survey of cryogenic mirrors is appropriate) that were flown or tested are presented.

Ruthven, Greg↗
NASA NTRS2000

The Sugar Model: Catalytic Flow Reactor Dynamics of Pyruvaldehyde Synthesis from Triose Catalyzed by Poly-L-Lysine Contained in a Dialyzer

The formation of pyruvaldehyde from triose sugars was catalyzed by poly-L-lysine contained in a small dialyzer (100 MWCO) suspended in a much larger triose substrate reservoir. The polylysine confined in the dialyzer functioned as a catalytic flow reactor that constantly brought in triose from the substrate reservoir by diffusion to offset the drop in triose concentration within the reactor caused by its conversion to pyruvaldehyde. A 400 mM solution of poly-L-lysine contained in a 0.35 ml dialyzer placed in a 120 ml solution of triose substrate (pH 5.5, 40 C) generated pyruvaldehyde 11 -times faster than an a control reaction without the catalytic dialyzer. However, since the catalytic dialyzer's volume was 343-times smaller than the control reaction, the synthetic intensity (rate/volume) of pyruvaldehyde synthesis within the catalytic dialyzer was 3400-times greater than that of the control reaction and substrate solution. A similar result was obtained using a dialyzer with a 500 MWCO value. Acting as a catalytic flow reactor the polylysine catalytic dialyzer synthesized about 3.5 molecules of pyruvaldehyde per lysine residue in 7 days -- an amount of triose equal to twice the weight of the catalyst. At 7 days the catalytic activity of polylysine was 16% of its initial value, a result indicating catalyst-poisoning caused by reaction of pyruvaldehyde with the e-amino groups of polylysine. The dialyzer method of catalyst containment was selected it provides a simple, flexible, and easily manipulated experimental system for studying the dynamics and evolutionary development of confined autocatalytic processes related to the origin of life under anaerobic conditions.

Weber, Arthur L.↗