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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 sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Condition monitoring of wind turbine drivetrains: state-of-the-art technologies, recent trends, and future outlook

As global wind capacity expands, reducing operations and maintenance costs is critical to lowering the levelized cost of energy. This paper explores the state of the art in condition monitoring and prognostic strategies for wind turbine drivetrains, which are among the most failure-prone and maintenance-intensive subsystems. Current diagnostic methodologies are evaluated, covering supervisory control and data acquisition (SCADA) data, high-frequency vibration and acoustic analysis, machine learning and digital twin frameworks. Finally, practical challenges are identified that limit wide-scale industrial adoption, in order to guide future research and industrial efforts.

17 WIND ENERGY↗
NASA NTRS1964

Fluid amplifier state of the art. volume i- research and development - fluid amplifiers and logic

The report surveys the current state-of-the-art of fluid amplifiers including both theoretical and practical aspects of devices having no mechanically moving parts. It is based on a complete review of the published literature (with an extensive bibliography), information obtained from 20 organizations involved in fluid amplifier development, and work performed by the General Electric Company. Specific areas covered are design techniques, both analytical and experimental; typical elements and assemblies; applications, both now in use and contemplated; fabrication techniques; and instrumentation. The report concludes that, although simple applications are now being made, the fluid amplifier field is still in the early development stage. There continues to be a basis for optimism for space applications requiring extreme environmental tolerance, long life, or the elimination of fluid system interfaces. Specialized military, and commercial applications also look promising. Work now under way should provide a better understanding of the design of devices and increase the number of useful applications.

FLUID AMPLIFICATION↗
NASA NTRS1966

State-of-the-Art Study for High-speed Deceleration and Stabilization Devices

Documented aerodynamic deployable decelerator performance data above Mach 1. 0 is presented. The state of the art of drag and stability characteristics for reentry and recovery applications is defined for a wide range of decelerator configurations. Structural and material data and other design information also are presented. Emphasis is given to presentation of basic aero, thermal, and structural design data, which points out basic problem areas and voids in existing technology. The basic problems and voids include supersonic "buzzing" of towed porous decelerators in the wake of the forebody, the complete lack of dynamic stability data, and the general lack of aerothermal data at speeds above Mach 5.

STABILIZATION↗
NASA NTRS1960

Compilation of papers summarizing some recent NASA research on manned military aircraft. I. VTOL aircraft - State of the art

During the last few years a large number and wide variety of VTOL aircraft types have been studied; some of them promising, some not so promising. The purpose of this paper is to summarize briefly the state of the art in this field and to indicate which of the types are most promising, to bring out applications where they are best suited and to indicate what is needed in the way of additional research and development.

VTOL aircraft↗
NASA NTRS1972

Computation of turbulent flows-state-of-the-art, 1970

The state-of-the-art of turbulent flow computation is surveyed. The formulations were generalized to increase the range of their applicability, and the excitement of current debate on equation models was brought into the review. Some new ideas on the modeling of the pressure-strain term in the Reynolds stress equations are also suggested.

Reynolds, W. C.↗
NASA NTRS1973

Rolling-element bearings: A review of the state of the art

Some of the research conducted which has brought rolling-element technology to its present state is discussed. Areas touched upon are material effects, processing variables, operating variables, design optimization, lubricant effects and lubrication methods. Finally, problem areas are discussed in relation to the present state-of-the-art and anticipated requirements.

Anderson, W. J.↗
NASA NTRS1973

Rolling-element bearings - A review of the state of the art

Some of the research conducted which has brough rolling-element technology to its present state is discussed. Areas touched upon are material effects, processing variables, operating variables, design optimization, lubricant effects and lubrication methods. Finally, problem areas are discussed in relation to the present state-of-the-art and anticipated requirements.

Anderson, W. J.↗
NASA NTRS1974

The prediction of structural response to buffet flow: A state-of-the-art review

Certain aspects of the dynamic system being discussed are reviewed and important structural and aerodynamic quantities of the system are discussed. A theoretical model is presented which relates these quantities to each other. These quantities are then each, in turn, considered in terms of the state of the art of determining the quantities and in terms of areas where further research is needed. The similarity laws and scaling relationships applicable to determining buffet structural response are then discussed, and areas where simplification is required or may be permissible are mentioned. Finally, the various types of model tests pertinent to predicting response of the aircraft structure to buffet flow are discussed.

Hanson, P. W.↗
NASA NTRS1974

TERSSE: Definition of the Total Earth Resources System for the Shuttle Era. Volume 2: An Assessment of the Current State-of-the-Art

Results of a state-of-the-art assessment of technology areas which affect the Earth Resources Program are presented along with a functional description of the basic earth resources system. Major areas discussed include: spacecraft flight hardware, remote sensors, data processing techniques and hardware, user models, user interfaces, and operations technology.

Source record↗