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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 109 records · Page 6

All sources NASA NTRS DOE OSTI

NASA NTRS1965

Operational Experiences with the X-14A Deflected-Jet VTOL Aircraft

During 5 1/2 years of flight research with a deflected-jet VTOL aircraft a 2 number of operational problems were experienced and investigated. These experiences can be grouped into two general categories: (1) the effects of the jet engine and its operation and (2) the restrictions imposed upon the pilot's operation due to reduced visual reference. This report is an examination of these problems and., in some cases, presents possible solutions to these problems.

Rolls, L. Stewart↗

NASA NTRS1965

Recent Studies of Runway Roughness

Recent studies of NASA research related to aircraft operating problems on rough runways are presented. Some of these investigations were conducted cooperatively with the airport operators, with the Federal Aviation Agency, and with the U.S. Air Force. The studies show that criteria based on power spectral levels of runway-profile data are not sufficient to define acceptable levels of runway roughness from the piloting viewpoint. Because of the large variation in response characteristics between various types of aircraft, a runway may be acceptable for some aircraft and unacceptable for others. A criterion for roughness, therefore, should be expressed in terms of aircraft response - preferably, cockpit acceleration. A criterion suggested is that the maximum vertical acceleration in the cockpit should not exceed +/- 0.4 g for sections of the runway where precise aircraft control is required.

Morris, Garland↗

NASA NTRS1993

Operability engineering in the Deep Space Network

Many operability problems exist at the three Deep Space Communications Complexes (DSCC's) of the Deep Space Network (DSN). Four years ago, the position of DSN Operability Engineer was created to provide the opportunity for someone to take a system-level approach to solving these problems. Since that time, a process has been developed for personnel and development engineers and for enforcing user interface standards in software designed for the DSCC's. Plans are for the participation of operations personnel in the product life-cycle to expand in the future.

Wilkinson, Belinda↗

NASA NTRS1968

Space clinical medicine - A prospective look at medical problems from hazards of space operations.

Clinical medical problems of space operation hazards covering hypoxia, decompression, dehydration, weightlessness, radiation, etc

Busby, D. E.↗

NASA NTRS1992

Current status and some future test directions for the U.S. National Transonic Facility

The construction of the National Transonic Facility was completed in September 1982 and the start-up and checkout of the tunnel systems were performed over the following two years. In August 1984, the facility was declared operational for final checkout of cryogenic instrumentation and control systems, and for the aerodynamics calibration and testing to commence. Since 1984 several operational problems have been identified and successfully solved which is demonstrated by the fact that the facility has operated the last year with no significant facility down times. Also during this time period, development of test techniques and instrumentation has continued. This paper will review some of the recent test techniques and instrumentation developments, and will briefly review the status of the facility.

Gloss, Blair B.↗

DOE OSTI2011

Variational stability of optimal control problems involving subdifferential operators

This paper is concerned with the problem of minimizing an integral functional with control-nonconvex integrand over the class of solutions of a control system in a Hilbert space subject to a control constraint given by a phase-dependent multivalued map with closed nonconvex values. The integrand, the subdifferential operators, the perturbation term, the initial conditions and the control constraint all depend on a parameter. Along with this problem, the paper considers the problem of minimizing an integral functional with control-convexified integrand over the class of solutions of the original system, but now subject to a convexified control constraint. By a solution of a control system we mean a 'trajectory-control' pair. For each value of the parameter, the convexified problem is shown to have a solution, which is the limit of a minimizing sequence of the original problem, and the minimal value of the functional with the convexified integrand is a continuous function of the parameter. This property is commonly referred to as the variational stability of a minimization problem. An example of a control parabolic system with hysteresis and diffusion effects is considered. Bibliography: 24 titles.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2019

Army Re-tuning™ Implementation Guides

The Army is a large, geographically dispersed organization with 156 installations and over 980 million square feet of building space to operate and maintain. The building stock spans a wide range of vintages and missions, with many serving cross-cutting functions and purposes. To meet Federal mandates and reduction goals organizationally, in recent years the Army has aggressively pursued policy and energy efficiency projects and programs resulting in a 9.6% reduction in energy use intensity (EUI) from fiscal year (FY) 2015 to FY2017. Despite these successes, the Army remains the largest consumer of electricity in the Federal government and spent approximately $1.1 billion in energy-related costs in FY2017 The Pacific Northwest National Laboratory (PNNL), in support of the Assistant Secretary of the Army (Installations, Energy and Environment) (ASA (IE&E)), was tasked with a multi-year study and pilot demonstration to develop a business case for the potential energy and cost reduction benefits from re-tuning™ efforts for the Army. Re tuning is a systematic process aimed at minimizing building energy consumption by identifying and correcting operational problems that plague buildings. The methodology was developed by PNNL research staff in an effort to improve building operational efficiency at no- or low-cost, primarily through building automation system (BAS) controls. The methodology is based on two basic principles: If the equipment is not needed, turn it off; and if the equipment is not needed at full power, turn it down. Implementation of identified low-cost/no-cost operational improvements through the re-tuning process results in increased building energy efficiency, reduced operating costs, and improvement to occupant comfort.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2025

Summary of DM1200 WESP History and Performance

The principal objective of this report was to summarize the testing experience on the DM1200 WESP. Further objectives were to provide descriptions of the history of all modifications and maintenance, methods of operation, problems and unit failures, and performance while processing a variety of feeds, and while employing a variety of operating methods, and to provide comparisons to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) high level waste (HLW) and low activity waste (LAW) WESP designs.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2025

Summary of DM1200 SBS history and performance

The principal objective of this report is to summarize the testing experience on the DM1200 SBS. Further objectives are to provide descriptions of the history of all modifications and maintenance, methods of operation, problems and unit failures, and performance while processing a variety of feeds, and while employing a variety of operating methods, and to provide comparisons to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) High Level Waste (HLW) and Low Activity Waste (LAW) Submerged Bed Scrubber (SBS) designs.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS1990

Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 5: OEPSS final briefing for first year study

Wong, George S.↗

NASA NTRS1990

Operationally Efficient Propulsion System Study (OEPSS) data book. Volume 4: OEPSS design concepts

This study was initiated to identify operations problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advanced Launch System (ALS) program, the results of the OEPSS study have been organized into a series of OEPSS Data Books. This volume describes three propulsion concepts that will simplify the propulsion system design and significantly reduce operational requirements. The concepts include: (1) a fully integrated, booster propulsion module concept for the ALS that avoids the complex system created by using autonomous engines with numerous artificial interfaces; (2) an LOX tank aft concept which avoids potentially dangerous geysering in long LOX propellant lines; and (3) an air augmented, rocket engine nozzle afterburning propulsion concept that will significantly reduce LOX propellant requirements, reduce vehicle size and simplify ground operations and ground support equipment and facilities.

Wong, George S.↗

NASA NTRS1999

International Space Station Multi-Element Integrated Test

The International Space Station offers a unique challenge for integrated testing since the entire station is not launched as an integrated vehicle. The ISS design evolved for over 10 years from the station Freedom program that was based on a "ship and shoot" approach. Ship and shoot assumed the program would accept the hardware for launch and integrate the vehicle on orbit without any ground element-to-element integrated testing. Element-to-Element powered-on integrated testing is needed to identify operational problems on the ground rather than once the hardware is on orbit. The industry is accustomed to testing an integrated vehicle and then verifying it is ready for its operational missions. These tests require ground element emulators to represent on-orbit elements. The ISS Multi-Element Integrated Tests (MEIT) are element-to-element integrated tests bringing together hardware representing several flights. The major purpose of these tests is: 1) Element-to-Element interface compatibility, 2) Systems end-to-end operability and functionality and 3) utilize on-orbit procedures with the crew and mission control center. Execution of these tests is critical since the hardware is available for only a limited period of time. Test configurations are defined which test specific interfaces or functionality. These tests develop operational confidence in the Element-to-Element interfaces and identify major problems on the ground to avoid on-orbit anomalies that could threaten mission success, element survivability or assembly activities. This paper addresses the MEIT process, configurations and lessons-learned from these tests.

Filler, Russell E.↗

NASA NTRS1983

Study to determine the IFR operational profile and problems to the general aviation pilot

A study of the general aviation single pilot operating under instrument flight rules (GA SPIFR) has been conducted for NASA Langley Research Center. The objectives of the study were to (1) develop a GA SPIFR operational profile, (2) identify problems experienced by the GA SPIFR pilot, and (3) identify research tasks which have the potential for eliminating or reducing the severity of the problems. To obtain the information necessary to accomplish these objectives, a mail questionnaire survey of instrument rated pilots was conducted. Complete questionnaire data is reported in NASA CR-165805, "Statistical Summary: Study to Determine the IFR Operational Profile and Problems of the General Aviation Single Pilot'-Based upon the results of the GA SPIFR survey, this final report presents the general aviation IFR single pilot operational profile, illustrates selected data analysis, examples, identifies the problems which he is experiencing, and recommends further research.

Weislogel, S.↗

DOE OSTI2023

Conservation of Helium while Maintaining High System Purity

Recent helium shortages and helium price increases have lead to an increased emphasis being placed on conserving helium. The need to conserve helium must be balanced with need to maintain the high levels of purity necessary to prevent operational problems caused by contamination. Helium losses and contamination control are especially important for test stands that have cryogenic distribution systems operating continuously with frequent changeover of cryogenic temperature components that are being tested. This paper describes a mathematical model to estimate the quantity of helium lost and the purity of the helium after the pump and backfill procedure is complete. The process to determine the optimal time during pump down to cut off pumping and start backfilling is described. There is a tradeoff between trying to achieve the lowest possible pressure during pumping and the quantity of air leaking into the volume while pumping is occurring. An additional benefit of careful sel ection of pump and backfill parameters in conjunction with real-time pressure monitoring can reduce the labor and time required to complete a successful pump and backfill procedure. This paper is intended to be a tool for engineers to review their pump and backfill procedures and measured data to optimize helium losses, system purity, and labor required.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

Conservation of Helium while Maintaining High System Purity

Recent helium shortages and helium price increases have lead to an increased emphasis being placed on conserving helium. The need to conserve helium must be balanced with need to maintain the high levels of purity necessary to prevent operational problems caused by contamination. Helium losses and contamination control are especially important for test stands that have cryogenic distribution systems operating continuously with frequent changeover of cryogenic temperature components that are being tested. This paper describes a mathematical model to estimate the quantity of helium lost and the purity of the helium after the pump and backfill procedure is complete. The process to determine the optimal time during pump down to cut off pumping and start backfilling is described. There is a tradeoff between trying to achieve the lowest possible pressure during pumping and the quantity of air leaking into the volume while pumping is occurring. An additional benefit of careful selection of pump and backfill parameters in conjunction with real-time pressure monitoring can reduce the labor and time required to complete a successful pump and backfill procedure. This paper is intended to be a tool for engineers to review their pump and backfill procedures and measured data to optimize helium losses, system purity, and labor required.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

NASA NTRS1983

Fluorine disposal

A preliminary design of an F2 dispoal system for HELSTF is presented along with recommendations on operational policy and identification of potential operational problems. The analysis is based on sizing a system to handle two different modes of the HELSTF Fluorine Flow System (one operational and one catastrophic). This information should serve both as a guide to a final detailed design for HELSTF as well as a reference for subsequent monitoring and/or modification of the system which consists of a charcoal reactor followed by a dry soda lime scrubber.

Rakow, A.↗

DOE OSTI2020

Optimal Heliostat Assignment Strategy for Multiple-Receiver Systems

Next-generation concentrating solar power concepts currently being developed under the U.S. Department of Energy's Gen3 program include several novel heliostat field and receiver arrangements. Among these concepts are solar fields utilizing multiple receivers or several distinct receiver flux control zones, and each of which has particular power or peak flux constraints. In this paper, we present a linear program that identifies optimal heliostat-to-receiver assignment strategies for multi-receiver or multi-zone solar fields based on detailed calculations made by an optics modeling package. Two distinct problems are addressed: namely, (1) a design problem that chooses the optimal set of heliostats to include in a final layout given receiver constraints and performance, and (2) an operations problem that assigns existing heliostats to a receiver, maximizing field power output while maintaining receiver power constraints. The optimization methodology is integrated into the concentrating solar power tower modeling package SolarPILOTTM, and results are presented showing that heliostat assignment strategies can impact both initial heliostat field layout characteristics and the cost of thermal energy produced by the field. The methodology succeeds in maintaining power requirements but at the expense of producing different flux profiles on each receiver surface. Consequently, the paper also discusses additional measures that are applied to ensure that desirable flux distribution properties are maintained, reducing local flux mean-absolute-deviation values from a baseline of 17% or greater to less than 5% compared to a desired reference flux profile.

41 EE - Solar Energy Technologies Office (EE-4S)↗

DOE OSTI2020

State-of-the-art short-term electricity market operation with solar generation: A review

With the accelerating penetration of solar energy in energy systems, market operations concerning the solar-associated intermittency are widely discussed. How to correctly model the solar generation in the market and solve the uncertainty-based operation problems call for solutions. Unlike other renewable resources, solar power can be more easily applied to the demand side through behind-the-meter installations in a distributed manner with significant future extensibility. The corresponding operational rules in the markets are largely being revised. Over the past two decades, with the development of deregulated power markets, numerous studies related to uncertainty-based market operations tend to transform the market from a deterministic and centralized framework to a stochastic and decentralized one. As the relevant literature is most recent, this paper reviews their contributions to electricity market operations with solar integration and underlines the research directions of this topic and ongoing industry practices. A thorough review of the electricity markets worldwide with solar energy is provided. A variety of proposed mathematical solutions to the problem are also addressed.

14 SOLAR ENERGY↗