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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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Residual strain orientation in rolled titanium determined with synchrotron X-ray Laue microdiffraction

Previously, synchrotron X-ray Laue microdiffraction has been used to measure the magnitudes of residual strain in materials. Recently the method was advanced to determine the orientation of the strain ellipsoid and applied to naturally deformed quartzites; however, the deformation history of these quartzites is ambiguous due to their natural origin. Here, in this study, synchrotron X-ray Laue microdiffraction (µXRD) is used to measure the residual strain for the first time in a sample with known stress history, rolled titanium. A deviatoric strain tensor is calculated from each Laue diffraction image collected with two µXRD scans of a rolled titanium sheet in different sample orientations. The principal strain axes are calculated using an eigen decomposition of the deviatoric strain tensors. The results show that the principal axis of compression is aligned with the normal direction of the titanium sheet, and the principal axis of extension is aligned with the rolling direction. Pole figures are used to represent the 3D distribution of residual strain axes.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Rolling Root Mean Square Based Multimodal Anomaly Detection for Real Time Monitoring of Smart Grid

Reliable real-time monitoring is valuable for maintaining the operational integrity of modern electrical smart grids. Deployment of heterogeneous sensing technologies in substations has enabled high-resolution, multichannel waveform monitoring, but also introduces challenges for anomaly detection due to noise, baseline drift, and modality-dependent signal characteristics. In this work, we present a computationally efficient unsupervised method for multimodal event detection based on Rolling Root Mean Square based Event Detection (RRMSED). The method is developed using in-house, field deployed sensors collecting data at a utility substation. The sensing system comprises voltage and current sensors, triaxial accelerometers, and magnetometers, collectively capturing electrical, vibrational, and magnetic waveform measurements at high temporal resolution. RRMSED operates by extracting rolling RMS energy features and their first-order temporal differences from consecutive waveform segments for each channel and then applying channel-specific statistical thresholds learned from historical data. A persistence-based exceedance logic is employed to robustly identify transient events while suppressing impulsive noise, and to provide precise temporal localization with high resolution. The framework is designed for continuous server-side operation and can be deployed in real time without requiring complex models. Experiments on simulated waveform data with known ground truth demonstrate low false positive (FP) and false negative (FN) rates. Application to real substation data shows RRMSED to identify events that are not captured by conventional monitoring indicators including fast transient detection algorithm currently deployed in the system. These results indicate that rolling RMS based features provide an effective and practical basis for real-time multimodal event detection in smart-grid substations.

Mukherjee, Subrata [ORNL] (ORCID:0000000309930338)↗
DOE OSTI2020

PHOTO‐SENSITIVE LEAF ROLLING 1 encodes a polygalacturonase that modifies cell wall structure and drought tolerance in rice

Summary The biosynthesis and modification of cell wall composition and structure are controlled by hundreds of enzymes and have a direct consequence on plant growth and development. However, the majority of these enzymes has not been functionally characterised. Rice mutants with leaf‐rolling phenotypes were screened in a field. Phenotypic analysis under controlled conditions was performed for the selected mutant and the relevant gene was identified by map‐based cloning. Cell wall composition was analysed by glycome profiling assay. We identified a photo‐sensitive leaf rolling 1 ( psl1 ) mutant with ‘napping’ (midday depression of photosynthesis) phenotype and reduced growth. The PSL1 gene encodes a cell wall‐localised polygalacturonase (PG), a pectin‐degrading enzyme. psl1 with a 260‐bp deletion in its gene displayed leaf rolling in response to high light intensity and/or low humidity. Biochemical assays revealed PG activity of recombinant PSL1 protein. Significant modifications to cell wall composition in the psl1 mutant compared with the wild‐type plants were identified. Such modifications enhanced drought tolerance of the mutant plants by reducing water loss under osmotic stress and drought conditions. Taken together, PSL1 functions as a PG that modifies cell wall biosynthesis, plant development and drought tolerance in rice.

Zhang, Guangheng↗
DOE OSTI2022

Effects of Water Contamination on Micropitting and Rolling Contact Fatigue of Bearing Steels

Abstract In this research, the effects of water contamination in oil were investigated on two kinds of failures that occur in bearing steel: micropitting and rolling contact fatigue. Whereas the presence of water in the oil had little effect on the generation of surface wear in these experiments, increases in the occurrences of micropitting and rolling contact fatigue were observed due to the presence of either dissolved or free water in lubricants. Additionally, the presence of white etching matter at crack interfaces was observed and evaluated. The experimental results showed that water content can be considered as a significant factor that accelerates the formation of micropitting and fatigue cracks in rolling bearings.

Engineering↗
DOE OSTI2015

LANL Experience Rolling Zr-Clad LEU-10Mo Foils for AFIP-7

The cleaning, canning, rolling and final trimming of Low Enriched Uranium-10 wt. pct. Molybdenum (LEU-10Mo) foils for ATR (Advanced Test Reactor) fuel plates to be used in the AFIP-7 (ATR Full Size Plate In Center Flux Trap Position) experiments are summarized. Six Zr-clad foils were produced from two LEU-10Mo castings supplied to Los Alamos National Laboratory (LANL) by Y-12 National Security Complex. Details of cleaning and canning procedures are provided. Hot- and cold-rolling results are presented, including rolling schedules, images of foils in-process, metallography and local compositions of regions of interest, and details of final foil dimensions and process yield. This report was compiled from the slides for the presentation of the same name given by Duncan Hammon on May 12, 2011 at the AFIP-7 Lessons Learned meeting in Salt Lake City, UT, with Los Alamos National Laboratory document number LA-UR 11-02898.

Materials Science(36)↗
DOE OSTI2018

The Use of Statistically Based Rolling Supply Curves for Electricity Market Analysis: A Preliminary Look

In light of the changing electricity resource mixes across the United States, an important question in electricity modeling is how additions and retirements of generation, including additions in variable renewable energy (VRE) generation could impact markets by changing hourly wholesale energy prices. Instead of using resource-intensive production cost models (PCMs) or building and using simple generator supply curves, this analysis uses a 'top-down' approach based on regression analysis of hourly historical energy and load data to estimate the impact of supply changes on wholesale electricity prices, provided the changes are not so substantial that they fundamentally alter the market and dispatch-order driven behavior of non-retiring units. The rolling supply curve (RSC) method used in this report estimates the shape of the supply curve that fits historical hourly price and load data for given time intervals, such as two-weeks, and then repeats this on a rolling basis through the year. These supply curves can then be modified on an hourly basis to reflect the impact of generation retirements or additions, including VRE and then reapplied to the same load data to estimate the change in hourly electricity price. The choice of duration over which these RSCs are estimated has a significant impact on goodness of fit. For example, in PJM in 2015, moving from fitting one curve per year to 26 rolling two-week supply curves improves the standard error of the regression from 16 dollars/MWh to 6 dollars/MWh and the R-squared of the estimate from 0.48 to 0.76. We illustrate the potential use and value of the RSC method by estimating wholesale price effects under various generator retirement and addition scenarios, and we discuss potential limits of the technique, some of which are inherent. The ability to do this type of analysis is important to a wide range of market participants and other stakeholders, and it may have a role in complementing use of or providing calibrating insights to PCMs.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

PSTN-052: Survey Strategy: Rolling Cadence

We cover the basics of how a rolling cadence survey strategy can work, and review the results of a variety of rolling simulations. We find that Type Ia SNe recovery can be enhanced by using rolling cadence, while detecting fast microlensing events are dominated by footprint coverage.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1971

Investigation of a clamshell roll-out ejection concept

The equations for the motion, forces, and couples generated by clamshells released from spinning sounding rockets in accordance with a roll-out ejection concept are presented. The application of these equations to a study of a system for the Javelin rocket vehicle is discussed. The roll-out ejection concept advocated requires that each deploying clamshell be pivoted about an axis at its trailing edge located in the system sectioning plane. Clamshell despinning is a consequence of this deployment since the pivotal rate is in opposition to the rocket vehicle spin. The energy required by the deployment is derived largely from the rotational energy of the clamshell. Thus, the rocket vehicle will not be significantly despun by this kind of clamshell deployment. This ejection concept also permits a system design which makes it possible to limit clamshell angular motion to rotation about that one of its centroidal principal axes which is brought into parallelism with the rocket vehicle longitudinal axis. Also, by equalizing the moments of inertia about the other centroidal principal axes, the roll-out motion can be decoupled from any extraneous angular motion about these axes.

Hatakeyama, L. F.↗
NASA NTRS1971

Lunar surface engineering properties experiment definition. Volume 2: Mechanics of rolling sphere-soil slope interaction

The soil deformation mode under the action of a rolling sphere (boulder) was determined, and a theory based on actual soil failure mechanism was developed which provides a remote reconnaissance technique for study of soil conditions using boulder track observations. The failure mechanism was investigated by using models and by testing an instrumented spherical wheel. The wheel was specifically designed to measure contact pressure, but it also provided information on the failure mechanism. Further tests included rolling some 200 spheres down sand slopes. Films were taken of the rolling spheres, and the tracks were measured. Implications of the results and reevaluation of the lunar boulder tracks are discussed.

Hovland, H. J.↗
NASA NTRS1972

Flight investigation of the roll requirements for transport airplanes in the landing approach

An in-flight evaluation of transport roll characteristics in the landing approach was made with a general purpose airborne simulator. The evaluation task consisted of an instrument approach with a visual correction for a (200-foot) lateral offset. Pilot evaluations and ratings were obtained for approaches made at 140 knots and 180 knots indicated airspeed with variations of wheel characteristics, maximum roll rate, and roll time constant.

Holleman, E. C.↗
NASA NTRS1971

Rolling-element fatigue lives of through-hardened bearing materials.

Rolling-element fatigue tests were run with eight through-hardened bearing materials at 150 F. One-half in. dia balls of each material were run in five-ball fatigue testers. Care was taken to maintain constant all variables known to affect rolling-element fatigue life. The longest lives at 150 F were obtained with AISI 52100. Ten-percent lives of the other materials ranged from 7 to 78 percent of that obtained with 52100. A trend is indicated toward decreased rolling-element fatigue life with increased total weight percent of alloying elements. Three groups of 120-mm bore ball bearings made from AISI M-1, AISI M-50, and WB-49 were fatigue tested at an outer-race temperature of 600 F. The 10-percent lives of the M-50 and M-1 bearings exceeded the calculated AFBMA life by factors of 13 and 6, respectively. The bearings with WB-49 races showed lives less than AFBMA life. The results of the bearing tests at 600 F correlate well with the results of the five-ball fatigue data at 150 F.

Parker, R. J.↗
NASA NTRS1973

Fluidic emergency roll control system

A fluidic emergency roll control system for aircraft stabilization in the event of primary flight control failure was evaluated. The fluidic roll control units were designed to provide roll torque proportional to an electrical command as operated by two diametrically opposed thrust nozzles located in the wing tips. The control package consists of a solid propellant gas generator, two diametrically opposed vortex valve modulated thrust nozzles, and an electromagnetic torque motor. The procedures for the design, development, and performance testing of the system are described.

Haefner, K. B.↗
NASA NTRS1973

Wind-tunnel roll-damping measurements of a winged space shuttle configuration in launch attitude

Ground-wind load studies were conducted on three model configurations to assess the importance of aeroelastic instabilities of erected space shuttle vehicles. Roll damping was measured on a fuselage-alone model, which had a D cross section, and a fuselage and tail surfaces in combination with either a clipped-delta wing or a low-sweep tapered wing as the primary lifting surface. The largest negative roll-damping coefficients were measured with the fuselage-alone configuration and were a function of wind azimuth. At the wind azimuths at which the wing-fuselage configuration was unstable, the negative roll-damping coefficients were a function of reduced frequency.

Hess, R. W.↗
NASA NTRS1974

Method of making rolling element bearings

A method is described of making rolling elements by forming low mass cores having either hollow centers or being of a low mass material. The low mass cores are plated and heat treated to provide hard surfaces on the rolling elements. After grinding to the proper diameter the rolling elements are assembled between races to form a hearing.

Parker, R. J.↗
NASA NTRS1975

Experimental pitch-, yaw-, and roll-damping characteristics of a shuttle orbiter at Mach number 8

Wind tunnel tests were conducted to measure the pitch-, yaw-, and roll-damping characteristics of a modified 089B shuttle orbiter. These tests were conducted for NASA-Langley at the von Karman Gas Dynamics Facility of the Arnold Engineering Development Center. Data were obtained utilizing the small amplitude forced-oscillation technique at angles of attack of -4.9 to 26.5 deg at Reynolds numbers, based on model length, of 1,180,000 to 4,820,000. The orbiter was dynamically stable in pitch, yaw, and roll, and the pitch derivatives were dependent on Reynolds number, while the roll derivatives were independent of Reynolds number.

Uselton, B. L.↗
NASA NTRS1975

Effect of starvation on film thickness and traction under elastohydrodynamic rolling and sliding conditions

Traction measurements under starved elastohydrodynamic conditions were obtained for a point-contact geometry. Simultaneous measurements of the film thickness and the location of the inlet lubricant boundary were made. Optical interferometry was used to measure film thickness. The thickness of a starved film for combined rolling and sliding conditions varies with the location of the inlet boundary in the same way as previously found for pure rolling conditions. When the fluid velocity distribution is calculated in the inlet region by a Reynolds lubrication analysis, backflow is seen to occur over a portion of the inlet region. Backflow is essential for the establishment of a flooded condition. The location of certain fluid velocity conditions within the inlet region, as suggested in the literature, does not adequately describe the onset of starvation. For the same slide-roll ratio a starved film was observed to possess greater traction than a flooded film. Traction measurements under starved conditions were also compared with those under flooded conditions for equivalent shear rates in the Hertzian region. When the shear rates within the Hertzian region were low and the film was severely starved, the measured tractions were lower than expected. This may be due to large shear stresses developed by the large pressure gradients that are generated in the inlet region when it is severely starved.

Wedeven, L. D.↗
NASA NTRS1977

Effect of double vacuum melting and retained austenite on rolling-element fatigue life of AMS 5749 bearing steel

AMS 5749 steel combines the tempering, hot hardness, and hardness retention characteristics of AISI M-50 steel with the corrosion and oxidation resistance of AISI 440C stainless steel. The five-ball fatigue tester was used to evaluate the rolling-element fatigue life of AMS 5749. Double vacuum melting (vacuum induction melting plus vacuum arc remelting, VIM-VAR) produced AMS 5749 material with a rolling-element fatigue life at least 14 times that of vacuum induction melting alone. The VIM-VAR AMS 5749 steel balls gave lives from 6 to 12 times greater than VIM-VAR AISI M-50 steel balls. The highest level of retained austenite, 14.6 percent, was significantly detrimental to rolling-element fatigue life relative to the intermediate level of 11.1 percent.

Parker, R. J.↗
NASA NTRS1978

Rolling element fatigue testing of gear materials

Rolling element fatigue lives of nine alloys were evaluated in Rolling Contact (RC) rigs. Test conditions included a Hertzian stress at 4,826 MPa (700 ksi), a rolling speed of 6.23 m/sec (245 in/sec.). Tests were run with a Type I oil (MIL-L-7808G) at room temperature. B-10 lives (10% failure rate) of alloys were compared versus reference alloys, VIM-VAR AISI M-50 and VAR AISI 9310. Six case carburizing alloys (AISI 9310, CBS600, CBS1000M, EX00014, Vasco X-2 and EX00053) and three through-hardening alloys (AISI M-50, VascoMax 350 and Vasco Matrix 2 evaluated, showed RCF performance inferior or equivalent to that of AISI 9310 and AISI M-50. It was also found that the effects of vacuum melting processes, different tempering temperatures, freezing cycle during heat treating, shot peening, gold plating and chrome plating employed in the present investigation did not significantly affect RCF life.

Nahm, A. H.↗