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DOE OSTI2024

Quality Ranking of Unary Chloride Salt Property Data Included in MSTDB-TP

Molten salt reactor developers rely on thermal property data to design, license and operate the reactors. The Molten Salt Thermal Database-Thermophysical Properties (MSTDB-TP) was established under the DOE Nuclear Energy Advanced Modeling and Simulation (NEAMS) program and is managed by Oak Ridge National Laboratory to serve as a single source of thermophysical property values measured for a wide variety of molten salt systems for use by researchers, molten salt reactor developers, and regulators. These properties include density, viscosity and thermal diffusivity and conductivity. Published measurements of molten salt properties are lacking for many salts of interest and the data that are available are often inconsistent. This creates a challenge for MSR developers when determining which property values to use when designing their reactors. It is the purpose of this work to apply a consistent ranking system to all data entries that indicates the quality of property values listed in the database. These rankings will be the technical basis for down-selections by the database developers and alert users about the quality of the available property values. MSTDB-TP collects all available property data and indicates preferred data sets or correlations. However, all available data sets are included in the database. Quality assessments and rankings are being applied to data in MSTDB-TP to provide an indication of the quality of each data set independent of consistency with other data. Previous reports detailed the ranking system that was followed and assessments of unary fluoride data sets. Documentation of the quality of data in MSTDB-TP was continued by reviewing and assessing all available sources of density, viscosity and thermal diffusivity or conductivity values for unary chloride salts in MSTDB-TP V3.0 using the same criteria.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

NASA NTRS1972

In-flight pilot evaluations of the flying qualities of a four-engine jet transport

The flying qualities of the CV-990 jet transport were evaluated over the normal operating flight envelope and in smooth air to provide baseline data for transport airplanes. Pilot ratings of airplane handling characteristics for specific test conditions and configurations from approach to normal cruise were compared with various flying qualities criteria. In general, the CV-990 flying qualities were evaluated as satisfactory, and the evaluations supported transport flying qualities criteria. The Dutch roll damping was rated more satisfactory than was predicted by the flying qualities criteria. The pilots found rudder coordination for the yaw generated during high roll rates very difficult. They preferred to control with roll and pitch controls and to use the yaw damper to provide the required rudder coordination.

Holleman, E. C.↗

NASA NTRS1975

The 1975 Ride Quality Symposium

A compilation is presented of papers reported at the 1975 Ride Quality Symposium held in Williamsburg, Virginia, August 11-12, 1975. The symposium, jointly sponsored by NASA and the United States Department of Transportation, was held to provide a forum for determining the current state of the art relative to the technology base of ride quality information applicable to current and proposed transportation systems. Emphasis focused on passenger reactions to ride environment and on implications of these reactions to the design and operation of air, land, and water transportation systems acceptable to the traveling public. Papers are grouped in the following five categories: needs and uses for ride quality technology, vehicle environments and dynamics, investigative approaches and testing procedures, experimental ride quality studies, and ride quality modeling and criteria.

Source record↗

NASA NTRS1976

Lateral ride quality of the B-1 aircraft subjected to a reduction of lateral static stability

A method to evaluate the lateral ride quality of a B-1 aircraft subjected to a reduction in lateral static stability is developed. Ride quality is then found for three different relaxed static stability configurations which are augmented by yaw rate feedback to restore specified handling qualities. These cases are compared to the ride quality of the unrelaxed aircraft with the same handling qualities.

Hinsdale, A. J.↗

NASA NTRS1977

Production of a water quality map of Saginaw Bay by computer processing of LANDSAT-2 data

Surface truth and LANDSAT measurements collected July 31, 1975, for Saginaw Bay were used to demonstrate a technique for producing a color coded water quality map. On this map, color was used as a code to quantify five discrete ranges in the following water quality parameters: (1) temperature, (2) Secchi depth, (3) chloride, (4) conductivity, (5) total Kjeldahl nitrogen, (6) total phosphorous, (7)chlorophyll a, (8) total solids and (9) suspended solids. The LANDSAT and water quality relationship was established through the use of a set of linear regression equations where the water quality parameters are the dependent variables and LANDSAT measurements are the independent variables. Although the procedure is scene and surface truth dependent, it provides both a basis for extrapolating water quality parameters from point samples to unsampled areas and a synoptic view of water mass boundaries over the 3000 sq. km bay area made from one day's ship data that is superior, in many ways, to the traditional machine contoured maps made from three day's ship data.

Mckeon, J. B.↗

NASA NTRS1981

Use of ocean color scanner data in water quality mapping

Remotely sensed data, in combination with in situ data, are used in assessing water quality parameters within the San Francisco Bay-Delta. The parameters include suspended solids, chlorophyll, and turbidity. Regression models are developed between each of the water quality parameter measurements and the Ocean Color Scanner (OCS) data. The models are then extended to the entire study area for mapping water quality parameters. The results include a series of color-coded maps, each pertaining to one of the water quality parameters, and the statistical analysis of the OCS data and regression models. It is found that concurrently collected OCS data and surface truth measurements are highly useful in mapping the selected water quality parameters and locating areas having relatively high biological activity. In addition, it is found to be virtually impossible, at least within this test site, to locate such areas on U-2 color and color-infrared photography.

Khorram, S.↗

NASA NTRS1983

Effects of rotor inertia and rpm control on helicopter handling qualities

The effects of thrust-response characteristics on helicopter handling qualities have until recently remained largely undefined. A multiphase program is being conducted to study, in a generic sense and through ground simulation, the effects of engine and rotor response characteristics, excess power, and vertical damping on specific maneuvers included in nap-of-the-earth (NOE) operations. This paper describes the most recent of these phases: a simulation in which the effects on handling qualities of rotor inertia and rpm changes were considered. Thrust- and height-response characteristics to step-control inputs are included to document the configurations investigated. Results indicate that with a given engine response and unlimited power, large changes in rotor inertia have little effect on handling qualities for certain low-speed tasks and hover tasks. The effects on handling qualities of requiring the pilot to maintain proper rotor rpm limits were also studied. This investigation revealed that large fluctuations in rotor rpm degrade handling qualities; as a result, continued study of the use of methods to automate control of rotor rpm is recommended.

Corliss, L. D.↗

NASA NTRS1984

A preliminary look at the effects of coupled lateral modes on aircraft handling qualities

Analytic and six-degree-of-freedom motion base simulator studies have been conducted to better understand how the coupled roll-spiral and coupled roll-aileron actuator modes affect aircraft handling qualities. The results reported herein are preliminary and are subject to change until other aircraft and several more data points can be examined. The results obtained thus far indicate that when the roll-spiral coupled mode is brought about by unusual values of an aircraft's stability and control derivatives, the lateral-directional handling qualities will invariably be degraded. However, when the roll spiral coupling is brought about by a roll-rate command/roll-attitude hold stability and control augmentation system (SCAS), the requirements for satisfactory handling qualities can be correlated to the natural frequency and the damping of the coupled mode. Satisfactory handling qualities were also achieved when the lateral SCAS brought about a coupling of the roll mode with the aileron actuator mode. In this case, the pilot ratings indicate that the handling qualities may be correlated to the natural frequency of the coupled roll-aileron mode.

Ruflin, S. J.↗

NASA NTRS1988

Rotorcraft handling-qualities design criteria development

Joint NASA/Army efforts at the Ames Research Center to develop rotorcraft handling-qualities design criteria began in earnest in 1975. Notable results were the UH-1H VSTOLAND variable stability helicopter, the VFA-2 camera-and-terrain-board simulator visual system, and the generic helicopter real-time mathematical model, ARMCOP. An initial series of handling-qualities studies was conducted to assess the effects of rotor design parameters, interaxis coupling, and various levels of stability and control augmentation. The ability to conduct in-flight handling-qualities research was enhanced by the development of the NASA/Army CH-47 variable-stability helicopter. Research programs conducted using this vehicle include vertical-response investigations, hover augmentation systems, and the effects of control-force characteristics. The handling-qualities data base was judged to be sufficient to allow an update of the military helicopter handling-qualities specification, MIL-H-8501. These efforts, including not only the in-house experimental work but also contracted research and collaborative programs performed under the auspices of various international agreements. The report concludes by reviewing the topics that are currently most in need of work, and the plans for addressing these topics.

Aiken, Edwin W.↗

NASA NTRS1988

Quality measures and assurance for AI (Artificial Intelligence) software

This report is concerned with the application of software quality and evaluation measures to AI software and, more broadly, with the question of quality assurance for AI software. Considered are not only the metrics that attempt to measure some aspect of software quality, but also the methodologies and techniques (such as systematic testing) that attempt to improve some dimension of quality, without necessarily quantifying the extent of the improvement. The report is divided into three parts Part 1 reviews existing software quality measures, i.e., those that have been developed for, and applied to, conventional software. Part 2 considers the characteristics of AI software, the applicability and potential utility of measures and techniques identified in the first part, and reviews those few methods developed specifically for AI software. Part 3 presents an assessment and recommendations for the further exploration of this important area.

Rushby, John↗

NASA NTRS1987

Flying Qualities Research Challenges

Traditional flying qualities requirements for airplane dynamics are based on airplane modal response characteristics derived from linear small-perturbation analysis. These requirements are supported by a large experimental data base. The challenge to the flying qualities community is to demonstrate how flying qualities, the control system and aircraft configuration are still closely linked. This is evident in the definition of flying qualities and, as far as pilots are concerned, that flying qualities are still the measure of overall design success.

Steven M Sliwa↗

NASA NTRS1990

Interaction of feel system and flight control system dynamics on lateral flying qualities

An experimental investigation of the influence of lateral feel system characteristics on fighter aircraft roll flying qualities was conducted using the variable stability USAF NT-33. Forty-two evaluation flights were flown by three engineering test pilots. The investigation utilized the power approach, visual landing task and up-and-away tasks including formation, gun tracking, and computer-generated compensatory attitude tracking tasks displayed on the Head-Up Display. Experimental variations included the feel system frequency, force-deflection gradient, control system command type (force or position input command), aircraft roll mode time constant, control system prefilter frequency, and control system time delay. The primary data were task performance records and evaluation pilot comments and ratings using the Cooper-Harper scale. The data highlight the unique and powerful effect of the feel system of flying qualities. The data show that the feel system is not 'equivalent' in flying qualities influence to analogous control system elements. A lower limit of allowable feel system frequency appears warranted to ensure good lateral flying qualities. Flying qualities criteria should most properly treat the feel system dynamic influence separately from the control system, since the input and output of this dynamic element is apparent to the pilot and thus, does not produce a 'hidden' effect.

Bailey, R. E.↗

NASA NTRS1991

CRN5EXP: Expert system for statistical quality control

The purpose of the Expert System CRN5EXP is to assist in checking the quality of the coils at two very important mills: Hot Rolling and Cold Rolling in a steel plant. The system interprets the statistical quality control charts, diagnoses and predicts the quality of the steel. Measurements of process control variables are recorded in a database and sample statistics such as the mean and the range are computed and plotted on a control chart. The chart is analyzed through patterns using the C Language Integrated Production System (CLIPS) and a forward chaining technique to reach a conclusion about the causes of defects and to take management measures for the improvement of the quality control techniques. The Expert System combines the certainty factors associated with the process control variables to predict the quality of the steel. The paper presents the approach to extract data from the database, the reason to combine certainty factors, the architecture and the use of the Expert System. However, the interpretation of control charts patterns requires the human expert's knowledge and lends to Expert Systems rules.

Hentea, Mariana↗

NASA NTRS1991

A grid quality manipulation system

A grid quality manipulation system is described. The elements of the system are the measures by which quality is assessed, the computer graphic display of those measures, and the local grid manipulation to provide a response to the viewed quality indication. The display is an overlaid composite where the region is first covered with colors to reflect the values of the quality indicator, the grid is then placed on top of those colors, and finally a control net is placed on top of everything. The net represents the grid in terms of the control point form of algebraic grid generation. As a control point is moved, both the grid and the colored quality measures also move. This is a real time dynamic action so that the consequences of the manipulation are continuously seen.

Lu, Ning↗

NASA NTRS1992

Summary of the effects of engine throttle response on airplane formation-flying qualities

A flight evaluation as conducted to determine the effect of engine throttle response characteristics on precision formation-flying qualities. A variable electronic throttle control system was developed and flight-tested on a TF-104G airplane with a J79-11B engine at the NASA Dryden Flight Research Facility. Ten research flights were flown to evaluate the effects of throttle gain, time delay, and fuel control rate limiting on engine handling qualities during a demanding precision wing formation task. Handling quality effects of lag filters and lead compensation time delays were also evaluated. Data from pilot ratings and comments indicate that throttle control system time delays and rate limits cause significant degradations in handling qualities. Threshold values for satisfactory (level 1) and adequate (level 2) handling qualities of these key variables are presented.

Walsh, Kevin R.↗

NASA NTRS1991

Coordinating Council. Fifth Meeting: Quality

This NASA Scientific and Technical Information Program Coordinating Council meeting had a theme of Quality. Four presentations were made with the following titles: How much quality can you pay for?, What the Center for AeroSpace Information has done to improve quality, Quality from the user standpoint, and Database quality: user views test producer perception. Visuals as well as discussion summaries are also included.

Source record↗

NASA NTRS1992

Flight simulator for hypersonic vehicle and a study of NASP handling qualities

The research goal of the Human-Machine Systems Engineering Group was to study the existing handling quality studies in aircraft with sonic to supersonic speeds and power in order to understand information requirements needed for a hypersonic vehicle flight simulator. This goal falls within the NASA task statements: (1) develop flight simulator for hypersonic vehicle; (2) study NASP handling qualities; and (3) study effects of flexibility on handling qualities and on control system performance. Following the above statement of work, the group has developed three research strategies. These are: (1) to study existing handling quality studies and the associated aircraft and develop flight simulation data characterization; (2) to develop a profile for flight simulation data acquisition based on objective statement no. 1 above; and (3) to develop a simulator and an embedded expert system platform which can be used in handling quality experiments for hypersonic aircraft/flight simulation training.

Ntuen, Celestine A.↗

NASA NTRS1992

The role of Environmental Health System air quality monitors in Space Station Contingency Operations

This paper describes the Space Station Freedom (SSF) Environmental Health System's air-quality monitoring strategy and instrumentation. A two-tier system has been developed, consisting of first-alert instruments that warn the crew of airborne contamination and a volatile organic analyzer that can identify volatile organic contaminants in near-real time. The strategy for air quality monitoring on SSF is designed to provide early detection so that the contamination can be confined to one module and so that crew health and safety can be protected throughout the contingency event. The use of air-quality monitors in fixed and portable modes will be presented as a means of following the progress of decontamination efforts and ensuring acceptable air quality in a module after an incident. The technology of each instrument will be reviewed briefly; the main focus of this paper, however, will be the use of air-quality monitors before, during, and after contingency incidents.

Limero, Thomas F.↗