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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Hydrogen Pathways: Updated Cost, Well-to-Wheels Energy Use, and Emissions for the Current Technology Status of Ten Hydrogen Production, Delivery, and Distribution Scenarios

This report describes a life-cycle assessment conducted by the National Renewable Energy Laboratory (NREL) of 10 hydrogen production, delivery, dispensing, and use pathways that were evaluated for cost, energy use, and greenhouse gas (GHG) emissions. This evaluation updates and expands on a previous assessment of seven pathways conducted in 2009. This study summarizes key results, parameters, and sensitivities to those parameters for the 10 hydrogen pathways, reporting on the levelized cost of hydrogen in 2007 U.S. dollars as well as life-cycle well-to-wheels energy use and GHG emissions associated with the pathways.

08 HYDROGEN↗
DOE OSTI2018

Diagnostics of Wheel Life in Grinding

The change in effective grinding power with change in the grinding fluid is studied experimentally, in fixed machining conditions. A method is proposed for assessing the life of the wheels. This method facilitates the choice of the tool, grinding conditions, and composition of the grinding fluid.

42 ENGINEERING↗
NASA NTRS1945

The Effect of Inlet Temperature and Pressure on the Efficiency of a Single-stage Impulse Turbine Having a 13.2-inch Pitch-line Diameter Wheel

Efficiency tests have been conducted on a single-stage impulse turbine having a 13.2-inch pitch-line diameter wheel and a cast nozzle diaphram over a range of turbine speeds from 3000 to 17,000 rpm, pressure ratios from 1.5 to 5.0, inlet total temperatures from 1200 deg to 2000 deg R, and inlet total pressures from 18 to 59 inches of mercury absolute. The effect of inlet temperature and pressure on turbine efficiency for constant pressure ration and blade-to-jet speed ration is correlated against a factor derived from the equation for Reynolds number. The degree of correlation indicates that the change in turbine efficiency with inlet temperature and [ressure for constant pressure ration and blade-to-jet speed ration is principally a Reynolds number effect.

TURBINES - WHEELS↗
NASA NTRS1995

Performance of Four-Wheel-Steering Vehicles in Lane Change Maneuvers

This study addresses the performance of four-wheel-steering vehicles in high-speed lane change maneuvers. We compare the steering commands of an experienced driver in executing high-speed lane change maneuvers in road tests with those determined via solving suitably formulated optimization problems. It turns out that the optimal control determined is qualitatively comparable to the steering commands used by experienced drivers in road tests. Hence, we can analytically compare the performance of an experienced driver in executing lane change maneuvers using different vehicles.

Four-wheel-steering lane change maneuvers obstacle↗
NASA NTRS1995

Emulating the Lateral Dynamics of a Range of Vehicles Using a Four-Wheel-Steering Vehicle

The concept of Variable Dynamic Testbed Vehicle (VDTV) has been proposed as a tool to evaluate collision detection/avoidance systems, to perform vehicle-related human factors research, and to support other Automated HighWay System programs. The goal of this study is to analytically investigate to what extent a VDTV with four-wheel-steering can emulate the lateral dynamics of a broad range of vehicle models.

Four-wheel-steering varible dynamic testbed vehicl↗
NASA NTRS2007

A Wheel-On-Limb Rover for Lunar Operations

The All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) is a new mobility platform developed for potential lunar operations. This six limbed rover is designed to traverse quickly over benign terrain by rolling, traverse rough and steep terrain by walking, as well as perform general manipulation of tools and payloads. This flexible robotic platform will provide a mobile base for pressurized lunar habitats allowing for long range surface exploration and crew transport. It will also enable in-situ construction of lunar assets providing astronauts with the ability to assemble, maintain, and service a wide range of cargo. This paper presents the design details and capabilities of this wheel-on-limb platform.

ATHLETE↗