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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

Relative Lifetimes of Several Space Liquid Lubricants Using a Vacuum Spiral Orbit Tribometer (SOT)

A vacuum spiral orbit rolling contact tribometer (SOT) was used to determine the relative lifetimes of several unformulated space liquid lubricants. The lubricants tested included a synthetic hydrocarbon (Pennzane 2001 A), three perfluoropolyethers (Krytox 143AC, Fomblin Z25, and Brayco 815Z), three silahydrocarbons (a tri, a tetra, and a penta) and a polyalphaolefin (Nye PAO-100). The SOT simulates the ball motions in an angular contact bearing and tribochemically degrades microgram quantities of lubricant. Test failure is determined when a preset friction coefficient is exceeded. Relative lifetime (orbits/micro-g) is defined as the number of ball orbits to failure divided by the amount of lubricant on the ball. Conditions included 10 to 200 rpm rotational speed, approximately 50 micro-g lubricant, an initial vacuum < 1.3x10(exp -6) Pa, room temperature (approximately 23 C), a mean Hertzian stress of 1.5 GPa, and 440 C stainless steel specimens. Lubricated lifetimes from longest to shortest were Pennzane 2001 A, the silahydrocarbons and the PAO-100, 143AC, ZI-5, and then 815Z. Relative lifetimes compare favorably to full-scale vacuum gimbal bearing tests. The effect of varying the mean Hertzian stress on the lifetime of some of the lubricants was examined.

Jansen, Mark J.↗
NASA NTRS2000

The Mission Transcript Collection: U.S. Human Spaceflight Missions from Mercury Redstone 3 to Apollo 17

Aboard every U.S. piloted spacecraft, from Mercury through Apollo, NASA installed tape recorders that captured nearly every word spoken by the astronauts during their history-making flights into space. For the first time ever, NASA has digitally scanned all of the transcripts made from both the onboard tapes and those tape recordings made on the ground from the air-to-ground transmissions and placed them on this two CD-ROM set. Gathered in this special collection are 80 transcripts totaling nearly 45,000 pages of text that cover every US human spaceflight from the first human Mercury mission through the last lunar landing flight of Apollo 17. Users of this CD will note that the quantity and type of transcripts made for each mission vary. For example, the Mercury flights each had one transcript whereas the Gemini missions produced several. Starting with the Gemini flights, NASA produced a Public Affairs Office (PAO) commentary version, as well as at least one "technical" air-to-ground transcript version, per mission. Most of the Apollo missions produced four transcripts per flight. These included the onboard voice data recorder transcripts made from the Data Storage Equipment (DSE) on the Command Module (CM), and the Data Storage Electronics Assembly (DSEA) onboard the Lunar Module (LM), in addition to the PAO commentary and air-to-ground technical transcripts. The CD set includes an index listing each transcript file by name. Some of the transcripts include a detailed explanation of their contents and how they were made. Also included in this collection is a listing of all the original air-to-ground audiotapes housed in NASA's archives from which many of these transcripts were made. We hope you find this collection of transcripts interesting and useful.

Source record↗
NASA NTRS2013

Internal Social Media at Marshall Space Flight Center - An Engineer's Snapshot

In the brief span of about six years (2004-2010), social media radically enhanced people's ways of maintaining recreational friendships. Social media's impact on public affairs (PAO) and community engagement is equally striking: NASA has involved millions of non-NASA viewers in its activities via outward-facing social media, often in a very two-way street fashion. Use of social media as an internal working tool by NASA's tens of thousands of civil servants, onsite contractor employees, and external stakeholders is evolving more slowly. This paper examines, from an engineer's perspective, Marshall Space Flight Center s (MSFC) efforts to bring the power of social media to the daily working environment. Primary emphasis is on an internal Social Networking Service called Explornet that could be scaled Agency-wide. Other topics include MSFC use of other social media day-to-day for non-PAO purposes, some specialized uses of social techniques in space flight control operations, and how to help a community open up so it can discover and adopt what works well.

Scott, David W.↗
DOE OSTI2021

Synthetic Lubricants Derived from Plastic Waste and their Tribological Performance

The energy efficiency, mechanical durability, and environmental compatibility of all moving machine components rely heavily on advanced lubricants for smooth and safe operation. Herein an alternative family of high-quality liquid (HQL) lubricants was derived by the catalytic conversion of pre- and post-consumer polyolefin waste. The plastic-derived lubricants performed comparably to synthetic base oils such as polyalphaolefins (PAOs), both with a wear scar volume (WSV) of 7.5×10 -5 mm -3 . HQLs also performed superior to petroleum-based lubricants such as Group III mineral oil with a WSV of 1.7×10 -4 mm -3 , showcasing a 44% reduction in wear. Furthermore, a synergistic reduction in friction and wear was observed when combining the upcycled plastic lubricant with synthetic oils. Additionally, life cycle and techno-economic analyses also showed this process to be energetically efficient and economically feasible. This novel technology offers a cost-effective opportunity to reduce the harmful environmental impact of plastic waste on our planet and to save energy through reduction of friction and wear-related degradations in transportation applications akin to synthetic oils.

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

Impacts of engine lubrication oil-derived ash on soot oxidative reactivity on a catalytic gasoline particulate filter

Characterizing soot oxidation kinetics is crucial for understanding how gasoline particulate filters (GPFs) perform both in terms of filtration efficiency and pressure drop. The most common method for measuring soot oxidative reactivity is thermogravimetric analysis (TGA). Because TGA is an offline method, it may inaccurately predict how soot oxidizes on a GPF, especially if a catalytic washcoat is present that may enhance oxidation rates through surface interactions as the soot loads on the filter. In this work, a novel in-situ soot oxidative reactivity measurement method was developed. The method involved loading a catalytic GPF under high temperature conditions conducive to soot oxidation and measuring the filtration efficiency of 100 nm particles. A correlation was made between filtration efficiency and loaded soot mass on the filter to allow calculation of the soot oxidation rate. The method was evaluated in experiments using a 2.0 L gasoline direct injection (GDI) engine with three oils of varying additive packages, including an oil with a high zinc dialkyldithiophosphate (ZDDP) concentration, a non-additive, pure poly-alpha olefin (PAO) oil, and an oil with a high concentration of calcium sulfonate. Calculated specific soot oxidation rates ranged from ~0.06–0.6 min –1 and showed strong dependence on GPF inlet gas temperature and lubrication oil additive type. The results clearly demonstrated a catalytic effect of calcium-containing ash particles. Reactivity of soot produced by the engine running with the high calcium containing lubrication oil was increased. Similarly, the results indicated that the catalytic washcoat on the filter increased soot oxidation rates on-filter, especially at low soot loading. Conversely, the ZDDP oil additive exhibited a reactivity inhibiting effect, resulting in lower soot oxidation rates. Finally, this work represents the first known in-situ soot oxidative reactivity measurements on a GPF and elucidates the effect of lubrication oil additives and catalytic washcoat on oxidation rate.

42 ENGINEERING↗
DOE OSTI2023

Role of surface wetting on tribological behavior for laser nanotextured steel using ionic liquid lubricants

Here, this research evaluates the effect of surface wettability on the tribological performance through ball-on-flat tribology testing. The substrate material, M2 tool steel, is laser processed and then functionalized with fluorocarbon and nitrile chemistry to achieve distinct oleophobicity and oleophilicity, respectively, but with a similar nanoscale surface texture. The baseline lubricant is poly-alpha-olefin (PAO) oil, and ionic liquids (ILs) are used as additives for this study. The interaction between the nanoscale textured steel surface and ionic liquid-based oils is investigated. A set of reciprocating wear tests are performed to investigate the tribological behavior of the tribo-system consisting of the surface-engineered, flat M2 tool steel specimen and a standard, surface-polished steel ball. Results show that the oleophobic flat surface results in a lower friction, while the oleophilic surface modification leads to a better wear protection to the flat surface. Ammonium-based IL provides the highest friction reduction, while the phosphonium-based ILs provide an improved wear protection.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Macroscale superlubricity by a sacrificial carbon nanotube coating

Superlubricity, i.e., coefficient of friction (COF) below 0.01, was earlier limited to microscale in controlled environments in the earlier literature and more recently realized for macroscale sliding of ceramic or carbon surfaces lubricated by water or other polar fluids. However, there is lack of report of superlubricity for the most common bearing system, i.e., steel-steel contact in non-polar oil lubrication. Here, in this work, we present ultra-low COF of 0.001–0.007 by using a sacrificial coating composed of vertically-aligned carbon nanotubes (CNTs) for macroscale steel-steel sliding under minimum quantity lubrication (MQL) of a polyalphaolefin (PAO) oil in the ambient environment. Raman spectroscopy and electron microscopy analyses detected graphene-containing tribofilms on both the steel surfaces, which was produced by the fractured CNT flakes and metallic wear debris during running-in. The in situ formed graphene-graphene contact interface presumably possesses a low shear resistance leading to superlubricity. The presence of oil, despite as little as one droplet, has proven to be crucial. Such a superlubricity performance has shown good sustainability in extended testing of more than 500,000 cycles and strong ability of accommodating changes in sliding conditions. Results here demonstrate feasibility with fundamental insights for achieving ambient environment macroscale superlubricity.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Multi-scale computer-aided design and photo-controlled macromolecular synthesis boosting uranium harvesting from seawater

By integrating multi-scale computational simulation with photo-regulated macromolecular synthesis, this study presents a new paradigm for smart design while customizing polymeric adsorbents for uranium harvesting from seawater. A dissipative particle dynamics (DPD) approach, combined with a molecular dynamics (MD) study, is performed to simulate the conformational dynamics and adsorption process of a model uranium grabber, i.e., PAO m -b-PPEGMA n , suggesting that the maximum adsorption capacity with atomic economy can be achieved with a preferred block ratio of 0.18. The designed polymers are synthesized using the PET-RAFT polymerization in a microfluidic platform, exhibiting a record high adsorption capacity of uranium (11.4 ± 1.2 mg/g) in real seawater within 28 days. This study offers an integrated perspective to quantitatively assess adsorption phenomena of polymers, bridging metal-ligand interactions at the molecular level with their spatial conformations at the mesoscopic level. The established protocol is generally adaptable for target-oriented development of more advanced polymers for broadened applications.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Refinement of the “ Candidatus Accumulibacter” genus based on metagenomic analysis of biological nutrient removal (BNR) pilot-scale plants operated with reduced aeration

Members of the “Candidatus Accumulibacter” genus are widely studied as key polyphosphate-accumulating organisms (PAOs) in biological nutrient removal (BNR) facilities performing enhanced biological phosphorus removal (EBPR). This diverse lineage includes 18 “Ca. Accumulibacter” species, which have been proposed based on the phylogenetic divergence of the polyphosphate kinase 1 (ppk1) gene and genome-scale comparisons of metagenome-assembled genomes (MAGs). Phylogenetic classification based on the 16S rRNA genetic marker has been difficult to attain because most “Ca. Accumulibacter” MAGs are incomplete and often do not include the rRNA operon. Here, we investigate the “Ca. Accumulibacter” diversity in pilot-scale treatment trains performing BNR under low dissolved oxygen (DO) conditions using genome-resolved metagenomics. Using long-read sequencing, we recovered medium- and high-quality MAGs for 5 of the 18 “Ca. Accumulibacter” species, all with rRNA operons assembled, which allowed a reassessment of the 16S rRNA-based phylogeny of this genus and an analysis of phylogeny based on the 23S rRNA gene.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Examining Thermolytic Production of Hydrogen from Lubrication Oil

Savannah River National Laboratory (SRNL) was requested by Savannah River Remediation (SRR) to conduct testing via Technical Task Request (HR) to determine the thermolytic HGR of Mobil SHC™ 630, a lubrication oil. Currently, 35 gallons of contaminated Mobil SHC 630 is proposed for release into the recycle stream from the Defense Waste Processing Facility (DWPF) to Tank 22 and then to the 242-16H (2H) Evaporator system. Inhibited recycle waste in the Recycle Collection Tank (RCT) is transferred to Recycle Pump Tank (RPT) in the Low Point Pump Pit (LPPP) and then to the Concentration, Storage and Transfer Facilities (CSTF) H-area. The lubrication oil would be added directly to the RPT, bypassing the RCT. The current DWPF waste compliance plan for liquid transfers from the RCT to the CSTF limits the concentration of Mobil SHC 630 to <1,100 ppm which is equal to <9.3 gallons of Mobil SHC 630 when considering a 7,500 gal RCT batch with an initial Mobil SHC 630 concentration of 42 mg/L. Mobil SHC 630 is expected to be largely immiscible in the caustic aqueous waste stream. It is a blend of base oils including polyalphaolefin (PAO) base oil and additives such as triphenylphosphate and cresyl diphenyl phosphate at various concentrations (<0.25 wt%). While the base oils are expected to be largely unreactive in CSTF waste, the triarylphosphates additives would be expected to hydrolyze in the caustic waste, forming diarylphosphates and phenol. The tests described herein were governed by a single Run Plan and will determine thermolytic HGR from the caustic aqueous solution, as well as from any organic phases present.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Exogenous Hemin alleviated cadmium stress in maize (Zea mays L.) by enhancing leaf photosynthesis, AsA-GSH cycle and polyamine metabolism

Cadmium (Cd) stress is one of the principal abiotic stresses that inhibit maize growth. The research was to explore (hemin chloride) Hemin (100 μmol L −1 ) on photosynthesis, ascorbic acid (AsA)-glutathione (GSH) cycle system, and polyamine metabolism of maize under Cd stress (85 mg L −1 ) using nutrient solution hydroponics, with Tiannong 9 (Cd tolerant) and Fenghe 6 (Cd sensitive) as experimental materials. The results showed that Hemin can increase leaf photosynthetic pigment content and ameliorate the ratio of Chlorophyll a/chlorophyll b ( Chla / Chlb ) under Cd stress. The values of ribose 1, 5-diphosphate carboxylase/oxygenase (RuBPcase) and phosphoenolpyruvate carboxylase (PEPCase), and total xanthophyll cycle pool [(violoxanthin (V), antiflavin (A) and zeaxanthin (Z)] increased, which enhancing xanthophyll cycle (DEPS) de-epoxidation, and alleviating stomatal and non-stomatal limitation of leaf photosynthesis. Hemin significantly increased net photosynthetic rate ( P n ), stomatal conductance ( g s ), transpiration rate ( T r ), photochemical quenching coefficient ( qP ), PSII maximum photochemical efficiency ( F v /F m ), and electron transfer rate ( ETR ), which contributed to the improvement of the PSII photosynthetic system. Compared with Cd stress, Hemin can reduce thiobartolic acid reactant (TBARS) content, superoxide anion radical (O 2 − ) production rate, hydrogen peroxide (H 2 O 2 ) accumulation, and the extent of electrolyte leakage (EL); decreased the level of malondialdehyde (MDA) content and increased the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT); slowed the decrease in dehydroascorbic acid reductase (DHAR) and monodehydroascorbate reductase (MDHAR) activity and the increase in glutathione reductase (GR) and ascorbate peroxidase (APX) activity in leaves; promoted the increase in AsA and GSH content, decreased dehydroascorbic acid (DHA) and oxidized glutathione (GSSG), and increased AsA/DHA and GSH/GSSG ratios under Cd stress. Hemin promoted the increase of conjugated and bound polyamine content, and the conversion process speed of free putrescine (Put) to free spermine (Spm) and spermidine (Spd) in maize; decreased polyamine oxidase (PAO) activity and increased diamine oxidase (DAO), arginine decarboxylase (ADC), ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) enzyme activities in leaves under Cd stress.

Piao, Lin↗
NASA NTRS1974

A reevaluation of the interrupter technique for airway resistance measurement

An attempt was made to obtain a better insight into the actual transient response of airway opening pressure (Pao) following rapid occlusion. With this knowledge it was hoped to be able to clarify the reason for the overestimations found by other investigators, and possibly to obtain a more accurate method of estimating alveolar pressure just prior to interruption. This would result in an improved method for estimating airway resistance. Use of an extrapolation method was found to provide an improved correlation between resistances determined by the interruptor technique and those found by the plethysmograph in normal subjects.

Jackson, A. C.↗
NASA NTRS1978

Prediction of aircraft sideline noise attenuation

A computational study is made using the recommended ground effect theory by Pao, Wenzel, and Oncley. It is shown that this theory adequately predicts the measured ground attenuation data by Parkin and Scholes, which is the only available large data set. It is also shown, however, that the ground effect theory does not predict the measured lateral attenuations from actual aircraft flyovers. There remain one or more important lateral effects on aircraft noise, such as sideline shielding of sources, which must be incorporated in the prediction methods. Experiments at low elevation angles (0 deg to 10 deg) and low-to-intermediate frequencies are recommended to further validate the ground effect theory.

Zorumski, W. E.↗
NASA NTRS1981

Ground effects on aircraft noise for a wide-body commercial airplane

Ground effects on noise from a high-bypass ratio engined aircraft are investigated. A 747 is flown at altitudes from 30 to 960 m past a 20-microphone array, and ground effects are calculated from noise measurements as a function of elevation angle and slant range. Results are given in terms of EPNL units and are compared with previous results of a turbojet-powered T-38 and SAE-recommended empirical lateral attenuation prediction procedures. Theoretical predictions are made based on a method developed by Pao et al. (1978) and are compared with both 747 and T-38 results, demonstrating good agreement although a consistent underprediction of peak measured attenuation is observed. Measured ground effects are found largest at 200 Hz, and no definite shielding differences are apparent for a directivity angle of 122.5 deg. Less lateral attenuation of effective perceived noise is measured for both aircraft and is attributed to the dominance of low-frequency noise in the source spectrum.

Willshire, W. L., Jr.↗
NASA NTRS1986

Modelling short channel mosfets for use in VLSI

In an investigation of metal oxide semiconductor field effect transistor (MOFSET) devices, a one-dimensional mathematical model of device dynamics was prepared, from which an accurate and computationally efficient drain current expression could be derived for subsequent parameter extraction. While a critical review revealed weaknesses in existing 1-D models (Pao-Sah, Pierret-Shields, Brews, and Van de Wiele), this new model in contrast was found to allow all the charge distributions to be continuous, to retain the inversion layer structure, and to include the contribution of current from the pinched-off part of the device. The model allows the source and drain to operate in different regimes. Numerical algorithms used for the evaluation of surface potentials in the various models are presented.

Klafter, Alex↗
NASA NTRS1995

Enhancement of perfluoropolyether boundary lubrication performance: I. Preliminary results

A ball bearing simulator operating under starved conditions was used to evaluate the boundary lubrication performance of a perfluoropolyether (PFPE) Krytox 143 AB. Several approaches to enhance boundary lubrication were studied. These included: (1) soluble boundary additives, (2) bearing surface modifications, (3) 'run-in' surface films, and (4) ceramic bearing components. In addition, results were compared with two non-perfluorinated liquid lubricant formulations. Based on these preliminary tests, the following tentative conclusions can be made: (1) substantial improvements in boundary lubrication performance were observed with a beta-diketone boundary additive and a tricresyl phosphate (TCP) liquid surface pretreatment; (2) the use of rough Si3N4 balls (Ra = 40 micro-in) also provided substantial improvement but with concomitant abrasive wear; (3) marginal improvements were seen with two boundary additives (a phosphine and a phosphatriazine) and a neat (100%) fluid (a carboxylic acid terminated PFPE); and surface pretreatments with a synthetic hydrocarbon, a PTFE coating, and TiC coated 440C and smooth Si3N4 balls (R(sub a) less than 1 micro-in); and (4) two non-PFPE lubricant formulations (a PAO and a synthetic hydrocarbon) yielded substantial improvements.

Jones, W. R., Jr.↗
NASA NTRS1996

Enhancement of Perfluoropolyether Boundary Lubrication Performance

A ball bearing simulator operating under starved conditions was used to perform screening tests to evaluate the boundary lubrication performance of a branched perfluoropolyether (PFPE), K-143 AB. Several approaches to enhance boundary lubrication were studied. These included: (1) soluble boundary additives, (2) bearing surface modifications, (3) 'run-in' surface films, and (4) ceramic bearing components. In addition, results were compared with two non-perfluorinated liquid lubricant formulations. Based on these tests, the following tentative conclusions can be made: (1) Substantial improvements in boundary lubrication performance were observed with a beta-diketone boundary additive and a tricresyl phosphate (TCP) liquid surface pretreatment, (2) the use of rough Si3N4 balls (R(sub a) = 40 micro-inch) also provided increases in test duration, but with concomitant abrasive wear, (3) moderate improvements were seen with two boundary additives (a phosphine and a phosphatriazine) and a neat (100%) fluid (a carboxylic acid terminated PFPE); and small improvements with surface pretreatments with synthetic hydrocarbons, a polytetrafluoroethylene (PTFE) coating, and TiC coated 440 C and smooth Si3N4 balls (R(sub a) = 1 micro-inch), and (4) two non-PFPE lubricant formulations (a polyalphaolefin (PAO) and synthetic hydrocarbon) yielded substantial improvements.

Jones, W. R., Jr.↗
NASA NTRS1996

Development of an Outreach Program for NASA: "NASA Ambassadors"

It is widely known that the average American citizen has either no idea or the wrong impression of what NASA is doing. The most common impression is that NASA's sole mission is to build and launch spacecraft and that the everyday experience of the common citizen would be impacted very little if NASA failed to exist altogether. Some feel that most of NASA's efforts are much too expensive and that the money would be better used on other efforts. Others feel that most of NASA's efforts either fail altogether or fail to meet their original objectives. Yet others feel that NASA is so mired in bureaucracy that it is no longer able to function. The goal of the NASA Ambassadors Program (NAP) is to educate the general populace as to what NASA's mission and goals actually are, to re-excite the "man on the street" with NASA's discoveries and technologies, and to convince him that NASA really does impact his everyday experience and that the economy of the U.S. is very dependent on NASA-type research. Each of the NASA centers currently run a speakers bureau through its Public Affairs Office (PAO). The speakers, NASA employees, are scheduled on an "as available" status and their travel is paid by NASA. However, there are only a limited number of them and their message may be regarded as being somewhat biased as they are paid by NASA. On the other hand, there are many members of NASA's summer programs which come from all areas of the country. Most of them not only believe that NASA's mission is important but are willing and able to articulate it to others. Furthermore, in the eyes of the public, they are probably more effective as ambassadors for NASA than are the NASA employees, as they do not derive their primary funding from it. Therefore it was decided to organize materials for them to use in presentations to general audiences in their home areas. Each person who accepted these materials was to be called a "NASA Ambassador".

Lebo, George R.↗