Search NASA⌕ Search

SEARCH · Search NASA

Results for “Time Service”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

LEVERAGING AGING MATERIALS DATA TO SUPPORT EXTENSION OF TRANSPORTATION SHIPPING PACKAGES SERVICE LIFE

Nuclear material inventories are increasingly being transferred to interim storage locations where they may reside for extended periods of time. Use of a shipping package to store nuclear materials after the transfer has become more common for a variety of reasons. Shipping packages are robust and have a qualified pedigree for performance in normal operation and accident conditions but are only certified over an approved transportation window. The continued use of shipping packages to contain nuclear material during interim storage will result in reduced overall costs and reduced exposure to workers. However, the shipping package materials of construction must maintain integrity as specified by the safety basis of the storage facility throughout the storage period, which is typically well beyond the certified transportation window. In many ways, the certification processes required for interim storage of nuclear materials in shipping packages is similar to life extension programs required for dry cask storage systems for commercial nuclear fuels. The storage of spent nuclear fuel in dry cask storage systems is federally-regulated, and over 1500 individual dry casks have been in successful service up to 20 years in the US. The uncertainty in final disposition will likely require extended storage of this fuel well beyond initial license periods and perhaps multiple re-licenses may be needed. Thus, both the shipping packages and the dry cask storage systems require materials integrity assessments and assurance of continued satisfactory materials performance over times not considered in the original evaluation processes. Test programs for the shipping packages have been established to obtain aging data on materials of construction to demonstrate continued system integrity. The collective data may be coupled with similar data for the dry cask storage systems and used to support extending the service life of shipping packages in both transportation and storage.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Risk and resilience in an uncertain world

We report that because the future is uncertain and to some extent unknowable, it is imperative that ecologists become involved in the discussion and planning of future infrastructure and protection from the effects of altered disturbance regimes. Research can test and demonstrate the benefits of protecting or proactively managing important features and places, and processes that enhance provisioning of ecosystem services such as flood control and fire mitigation. In conclusion, it is time to demonstrate how ecological science, when applied to human–environmental systems, can reduce risks and enhance resilience in a complex, changing world.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Microstructure and Performance of Nano-WC Particle-Strengthened Ni Coatings by Electro-brush Plating

Nano-WC particle-strengthened Ni composite coatings were prepared by electro-brush plating. A series of artificial neural network models was developed for the analysis and prediction of the coating performance. The microstructure and phase structure were studied with SEM, XRD and EDS. Nano-WC particles as the hard phase were distributed evenly and dispersed in the coatings, which was conducive to the hardness enhancement of the coatings. Additionally, nano-WC particles as microballs inserted in the coatings could reduce the friction when wear of the coating surface occurred. Furthermore, the addition of nano-WC particles delayed the time of crack initiation and propagation in the coatings, which increased the service lifetime when they worked in a thermal shock environment.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Analysis of transit users’ waiting tolerance in response to unplanned service disruptions

Public transit not only provides an affordable, efficient, and green service but also plays a critical role in the development of resilient transportation systems in urban areas. Transit disruption as a common incident in transit service operation can severely affect the resiliency of the transportation system as well as users’ satisfaction. While it is of great interest to transportation authorities to understand passengers’ decision behavior during unplanned transit disruptions in order to implement efficacious recovery strategies, still little is known about users’ behavior in case of such incidents. The scarcity of available data is a major underlying factor for this gap. Utilizing a recently collected data of transit users in the Chicago metropolitan area, this study investigates transit users’ waiting tolerance during unplanned service disruptions and disclose the factors that affect their behavior. A set of interval-censored accelerated failure time models using different survival distributions are developed, compared, and the factors influencing the survival functions of the waiting tolerance are identified. The results of the analysis reveal that, for instance, having experience of using ridesharing services decreases users’ waiting tolerance during a disruption. Further, built-environment attributes (such as the density of pedestrian-oriented links and transit service frequency), availability of alternative modes, transit service type, user’s attitudes, and trip characteristics turn to be significant in users’ decision behavior.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2024

DuraMAT: Building a Consortium to Accelerate the Photovoltaic Module Reliability Learning Cycle

Durable and reliable photovoltaic (PV) modules are critical to enabling an efficient transition to sustainable energy generation. The rate at which new module designs and materials are developed and deployed currently outpaces the rate at which we can identify failure mechanisms and understand degradation rates. Increasing the service life of PV modules, and our ability to predict performance over time, requires more durable materials and designs, better durability testing, more extensive material characterization, robust modeling, and methods to cross-examine historical performance data to extract meaningful results. This is a multidisciplinary challenge that requires expertise from a broad range of fields and, therefore, benefits significantly from a collaborative approach. In this Perspective, we outline the approach taken by the Durable Module Materials Consortium (DuraMAT), present a few case studies where our approach was successful, and provide an outlook on where this approach might be applied as the PV technology landscape continues to rapidly evolve. Published by the American Physical Society 2024

14 SOLAR ENERGY↗
DOE OSTI2012

The Impact of Solar Photovoltaic Generation on Balancing Requirements in the Southern Nevada System

Abstract—The impact of integrating large-scale solar photovoltaic (PV) generation on the balancing requirements in terms of regulation and load-following requirements in the southern Nevada balancing area is evaluated. The “swinging door” algorithm and the “probability box” method developed by Pacific Northwest National Laboratory (PNNL) were used to quantify the impact of large PV generation on the balancing requirements of the system operations. The system’s actual scheduling, real-time dispatch and regulation processes were simulated. Different levels of distributed generation were also considered in the study. The impact of hourly solar PV generation forecast errors on regulation and load-following requirements was assessed. The sensitivity of balancing requirements with respect to real-time forecast errors of large PV generation was analyzed. Index Terms—Ancillary services, balancing requirements, load following, regulation, renewables integration, swinging door

Balancing' Southern Nevada System↗
DOE OSTI2018

Real-Time Optimization of Distribution-level Energy Resources [SWR-18-27]

Researchers at NREL have developed a novel real-time control architecture to optimize the operation of DERs at residential, commercial, and industrial levels. The real-time system enables (portions of) feeders to emulate virtual power plants providing services to the rest of the grid, while ensuring satisfaction of electrical limits and maximizing customers’ benefits. This system can be integrated with legacy hardware and/or new advanced systems to optimally manage both individually-controlled DERs and aggregations of DERs. By virtue of the proposed engineering approach, the DERs collectively regulate the powers at an electrical point to respond to grid dispatch signals such as an automatic generation control, a ramping signal, or a 5-minute dispatch. Overall, this architecture allows end customers to minimize their payments and partake in grid operations while guaranteeing power quality in the distribution network.

Dall-Anese, Emiliano↗
DOE OSTI2013

Elementary Particle Physics (Final Report)

vATLAS and the LHC are delivering on the promise of discovery physics at the high energy frontier. Using 4.8 fb -1 of 2011 $\sqrt{s}$=7 TeV data and the first 5.8 fb -1 of 2012 $\sqrt{s}$=8 TeV data, ATLAS published the observation of a new particle with a mass of 126 GeV with a significance of 5.9σ that is compatible with a Standard Model (SM) Higgs. The LHC is outperforming initial projections for the 2012 run, and ATLAS is on track to integrate ~20 fb -1 of proton-proton collisions in 2012 before Long Shutdown 1 (LS1) begins in Spring 2013. University of Texas at Dallas (UTD) physicists will complete work on two ATLAS analyses this fall. The first is the search for the gauge bosons of a hypothesized dark sector. For 2011 data, UTD is responsible for the dark photon search in the electron-jet channel, and we are looking forward to an expanded leadership role in the dark photon search using the full 2012 data set. Our second analysis interest is the study of X/Y/Z exotic states having cc content, which builds on our experience in this field from the BABAR experiment After completing a measurement of the Xc(3872) production cross section this fall, we will search for evidence of the Z(4430)+ which is reported by Belle but not confirmed by BABAR. The UTD group has played a strong role in ATLAS operations, with group members serving as Pixel Run Coordinator, ATLAS Shift Leader, and Pixel/Inner Detector Shifter. For most of the current 3-year funding cycle, a group member coordinated the development of the Pixel DAQ code, and another continues to build and maintain the data quality monitoring (DQM) application that is used by the Inner Detector control room shifter. Additionally, members of our group take Pixel on-call expert shifts for DQM and DAQ. We led an optoboard lifetime study to assess concerns of premature on-detector VCSEL failure using the Pixel working prototype detector at CERN. Physicists based at UTD participated through Pixel Offline DQM and ATLAS Distributed Computing Operations Shifts (ADCoS) During Summer 2012, UTD joined upgrade activities in preparation for LS1. We took a major role in the testing of Electro-Readout (ER) Bundle testing for new Service Quarter Panels (nSQPs), and we developed two utilities to measure the timing jitter and bit error rate of the Pixel readout chain for use commissioning Pixel detector upgrades. During BABAR's heyday, the UTD group pioneered the use of e + e - annihilation events with hard Initial State Radiation (ISR) to study the charm threshold region, and we carried out the first BABAR double-cc analysis. Our most recent ISR paper, written in collaboration with A. Palano (Bari) is Exclusive Production of Ds + Ds - , D S *+ Ds - , and Ds *+ Ds *- via e+ e- Annihilation with Initial-State-Radiation was published in Physical Review D 82, 052004 (2010). Work continues on a study of ISR Λc + Λc - production, and a new search to establish and study double-ss production is starting.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Heavy Duty Roots Expander Heat Energy Recovery (HD-REHER)

Eaton Corporation proposed a comprehensive project to develop and demonstrate advanced component technology that will reduce the cost of implementing Organic Rankine Cycle (ORC) Waste Heat Recovery (WHR) systems to Heavy-Duty Diesel engines, making adaptation of this fuel efficiency improving technology more commercially attractive to end-users in the next 5 to 10 year time period. Accelerated adaptation and implementation of new fuel efficiency technology into service is critical for reduction of fuel used in the commercial vehicle segment.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2026

West Africa Battery Energy Storage Systems (BESS) Capacity Building - Discussion of BESS Tariffs: Payment Structures and Case Studies [Slides]

Battery Energy Storage Systems (BESS) are emerging as critical assets for enhancing grid reliability, integrating renewable energy, and enabling system flexibility. Yet, the regulatory and financial frameworks that determine how BESS projects are compensated vary widely across jurisdictions. This presentation explores international case studies - from Honduras, Costa Rica, Chile, South Africa, Mexico, and Brazil - to illustrate how tariff design and payment structures are evolving to support large-scale BESS deployment. The cases highlight a range of ownership and revenue models, including cost-of-service mechanisms, energy and capacity payments, and market-based arbitrage, as well as hybrid approaches under development. The discussion will examine key challenges such as defining remuneration for ancillary services, addressing double charging, and accounting for efficiency losses and degradation over time. By comparing experiences across markets, the presentation identifies emerging best practices for valuing BESS and designing tariffs that align technical performance with economic incentives, providing insights for regulators, utilities, and policymakers pursuing storage integration.

25 ENERGY STORAGE↗
NASA NTRS1973

All chain Loran-C time synchronization

A program is in progress to implement coordinated universal time (UTC) synchronization on all Loran-C transmissions. The present capability is limited to five Loran-C chains in which the tolerance is twenty-five microseconds with respect to UTC. Upon completion of the program, the transmissions of all Loran-C chains will be maintained within five microseconds of UTC. The improvement plan consists of equipping selected Loran-C transmitting stations for greater precision of frequency standard adjustment and improved monitoring capability. External time monitor stations will utilize television time transfer techniques with nearby SATCOM terminals where practicable, thus providing the requisite traceability to the Naval Observatory. The monitor equipment groups and the interrelationships with the ground station equipment are discussed. After a brief review of control doctrine, forth-coming improvements to transmitting stations and how the time monitor and navigation equipments will complement each other resulting in improved service to all users of the Loran-C system are described.

Sherman, H. T.↗
NASA NTRS1978

Analysis of star pair latitudes

Star pair latitude observations forming the basis for the pole positions reported by the International Polar Motion Service (IPMS) are processed to produce a mean pole position. However, the time series of raw observations contains high frequency information which is lost in the calculation of the mean pole. Analysis of 2931 star pair observations reveals a possible large excitation at one cycle per solar day. The average power level in the frequency band of the tesseral tides is seen to be high, although the peaks do not occur at the expected tidal frequencies.

Graber, M. A.↗
NASA NTRS1981

Satellite services system analysis study. Volume 3A: Service equipment requirements, appendix

Spacecraft descriptions and mission sequences, mission and servicing operations functional analyses, servicing requirements, and servicing equipment are discussed for five reference satellites: the X-ray Timing Explorer, the Upper Atmospheric Research Satellite, the Advanced X-ray Astrophysics Facility, the Earth Gravity Field Survey Mission, and the Orbiting Astronomical Observatory.

Source record↗
NASA NTRS1984

Advance Technology Satellites in the Commercial Environment. Volume 2: Final Report

A forecast of transponder requirements was obtained. Certain assumptions about system configurations are implicit in this process. The factors included are interpolation of baseline year values to produce yearly figures, estimation of satellite capture, effects of peak-hours and the time-zone staggering of peak hours, circuit requirements for acceptable grade of service capacity of satellite transponders, including various compression methods where applicable, and requirements for spare transponders in orbit. The graphical distribution of traffic requirements was estimated.

Source record↗
NASA NTRS1983

Processing techniques for software based SAR processors

Software SAR processing techniques defined to treat Shuttle Imaging Radar-B (SIR-B) data are reviewed. The algorithms are devised for the data processing procedure selection, SAR correlation function implementation, multiple array processors utilization, cornerturning, variable reference length azimuth processing, and range migration handling. The Interim Digital Processor (IDP) originally implemented for handling Seasat SAR data has been adapted for the SIR-B, and offers a resolution of 100 km using a processing procedure based on the Fast Fourier Transformation fast correlation approach. Peculiarities of the Seasat SAR data processing requirements are reviewed, along with modifications introduced for the SIR-B. An Advanced Digital SAR Processor (ADSP) is under development for use with the SIR-B in the 1986 time frame as an upgrade for the IDP, which will be in service in 1984-5.

Leung, K.↗
NASA NTRS1985

TDRSS and the STGT

A Second Tracking and Data Relay Satellite System (TDRSS) Ground Terminal (STGT) is envisioned as the next step in providing expanded support service for data transmission between spaceborne NASA and related missions, including Space Station and the earth-based user community. This need for expanded support service is projected to exist during the early to late 1990's time frame. This concept description reflects the current NASA requirements for a life-cycle cost-effective acquisition of the STGT. The significant features of this STGT configuration include autonomous subsystems, decentralized control processes and modular functional implementation. These features are expected to reduce acquisition risk and provide efficient manpower utilization during the operational years.

Chang, R.↗
NASA NTRS1990

Intelligent Robotic Systems Study (IRSS), phase 2

Under the Intelligent Robotics System Study (IRSS) contract, a generalized robotic control architecture was developed for use with the ProtoFlight Manipulator Arm (PFMA). The controller built for the PFMA provides localized position based force control, teleoperation and advanced path recording and playback capabilities. Various hand controllers can be used with the system in conjunction with a synthetic time delay capability to provide a realistic test bed for typical satellite servicing tasks. The configuration of the IRSS system is illustrated and discussed. The PFMA has six computer controllable degrees of freedom (DOF) plus a seventh manually indexable DOF, making the manipulator a pseudo 7 DOF mechanism. Because the PFMA was not developed to operate in a gravity field, but rather in space, it is counter balanced at the shoulder, elbow and wrist and a spring counterbalance has been added near the wrist to provide additional support. Built with long slender intra-joint linkages, the PFMA has a workspace nearly 2 meters deep and possesses sufficient dexterity to perform numerous satellite servicing tasks. The manipulator is arranged in a shoulder-yaw, pitch, elbow-pitch, and wrist-pitch, yaw, roll configuration, with an indexable shoulder roll joint. Digital control of the PFMA is implemented using a variety of single board computers developed by Heurikon Corporation and other manufacturers. The IRSS controller is designed to be a multi-rate, multi-tasking system. Independent joint servos run at a 134 Hz rate and position based impedance control functions at 67 Hz. Autonomous path generation and hand controller inputs are processed at a 33 Hz.

Source record↗
NASA NTRS1992

Telerobot control mode performance assessment

With the maturation of various developing robot control schemes, it is becoming extremely important that the technical community evaluate the performance of these various control technologies against an established baseline to determine which technology provides the most reliable robust, and safe on-orbit robot control. The Supervisory Telerobotics Laboratory (STELER) at JPL has developed a unique robot control capability which has been evaluated by the NASA technical community and found useful for augmenting both the operator interface and control of intended robotic systems on-board the Space Station. As part of the technology development and prototyping effort, the STELER team has been evaluating the performance of different control modes; namely, teleoperation under position, or rate, control, teleoperation with force reflection and shared control. Nine trained subjects were employed in the performance evaluation involving several high fidelity servicing tasks. Four types of operator performance data were collected; task completion time, average force, peak force, and number of operator successes and errors. This paper summarizes the results of this performance evaluation.

Zimmerman, Wayne↗