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Johnson, N.

Publications and source records attributed to Johnson, N..

12 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Offshore Wind Energy Validation Experiment Hierarchy

This paper provides a summary of planning work for experiments that will be necessary to address the long-term model validation needs required to meet offshore wind energy deployment goals. Conceptual experiments are identified and laid out in a validation hierarchy for both wind turbine and wind plant applications. Instrumentation needs that will be required for the offshore validation experiments to be impactful are then listed. The document concludes with a nominal vision for how these experiments can be accomplished.

17 WIND ENERGY↗
DOE OSTI2022

Leading Edge Microspoilers for Load Dumping in Wind Turbine Rotors

As rotor designs have grown in size and flexibility, new design challenges have arisen that could benefit from novel control strategies. Leading edge microspoilers (LEMS) have been shown to effectively reduce forces on airfoils by inducing stall at lower angles of attack. This paper investigates how LEMS can be used to reduce blade loading on large, flexible, downwind rotors during design-limiting design load cases. During shutdown in turbulent flows near cutout speed, LEMS could reduce the tip deflection spikes toward the tower by over 50% and keep flapwise root bending moments below normal operating conditions, thus eliminating these as design-driving load cases. In power producing load cases, deploying LEMS for a short period of time during a load spike can be effective to reduce toward-tower tip deflections without significantly impacting power produced, assuming these load spikes can be identified by a controller. Leveraging this technology could allow for lower specific power machines to be designed.

17 WIND ENERGY↗
DOE OSTI2016

NDMAS implementation and data qualification for accident tolerant fuel experiments

In order to meet quality and regulatory requirements associated with the U.S. Department of Energy Accident Tolerant Fuels (ATF) experiments, all data and documentation associated with ATF component fabrication, characterization, traceability, testing and post irradiation examination are being managed using the Nuclear Data Management and Analysis System (NDMAS). NDMAS melds commercial off-the-shelf software to provide the full range of needed functionality. The core component of NDMAS is the SAS Enterprise Business Intelligence software, which provides data manipulation, statistical and graphical capabilities, and delivery of live content to web pages. Content delivery to both Idaho National Laboratory researchers and external users via a web interface is managed using SharePoint, which is access-controlled. Additionally, scripts, macros, and commercial wrappers may be used or written by the NDMAS team to control interfaces between SAS and the structured query language server, where much of the data reside. ATF experiment data and documentation stored in the NDMAS database may be utilized to support Nuclear Regulatory Commission licensing of ATF concepts for commercial Light Water Reactor demonstration. Therefore, Data Qualification Plans are being developed to screen and tag all document and data input for ATR water loop testing, Transient Reactor Testing (TREAT), and post irradiation examination. A project-wide document library has been created in the ATF NDMAS SharePoint Site for general unrestricted document and information access. Restricted libraries have also been created to allow individual customer access to restricted documents. Data from ATR water loop instrumented lead experimentation, TREAT, and post-irradiation examination will be available to program participants on the SharePoint site as they are collected. This offers a unique capability for team collaboration while these tests are being conducted. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS2007

The Mixed-Phase Arctic Cloud Experiment (M-PACE)

The Mixed-Phase Arctic Cloud Experiment (M-PACE) was conducted September 27 through October 22, 2004 on the North Slope of Alaska. The primary objective was to collect a data set suitable to study interactions between microphysics, dynamics and radiative transfer in mixed-phase Arctic clouds. Observations taken during the 1997/1998 Surface Heat and Energy Budget of the Arctic (SHEBA) experiment revealed that Arctic clouds frequently consist of one (or more) liquid layers precipitating ice. M-PACE sought to investigate the physical processes of these clouds utilizing two aircraft (an in situ aircraft to characterize the microphysical properties of the clouds and a remote sensing aircraft to constraint the upwelling radiation) over the Department of Energy s Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) on the North Slope of Alaska. The measurements successfully documented the microphysical structure of Arctic mixed-phase clouds, with multiple in situ profiles collected in both single-layer and multi-layer clouds over two ground-based remote sensing sites. Liquid was found in clouds with temperatures down to -30 C, the coldest cloud top temperature below -40 C sampled by the aircraft. Remote sensing instruments suggest that ice was present in low concentrations, mostly concentrated in precipitation shafts, although there are indications of light ice precipitation present below the optically thick single-layer clouds. The prevalence of liquid down to these low temperatures could potentially be explained by the relatively low measured ice nuclei concentrations.

Verlinde, J.↗
NASA NTRS1991

Chronology of glaciation in the Hellas region of Mars

The Hellas Impact Basin is one of the oldest features on Mars, as indicated by the high density of large impact craters in parts of the basin. The highly degraded condition of Hellas seems consistent with great antiquity. However, many of the most strikingly modified landscapes in the basin, believed to be glaciogenic, also appear to be geologically youthful. Stratigraphic relations suggest two episodes of glaciation. Chronologic constraints are imposed on glaciation based on the impact cratering record, the focus of which is the southwestern portion of Hellas. Major terrain units are mapped. The lineated terrain and ridged plains form the summit and flanks of a large shield volcano, Amphitrites Patera, which was superimposed over the southwestern rim of Hellas toward the end of heavy bombardment. The ridged plains and lineated terrain are crossed by numerous wrinkle ridges. The lineated terrain is distinguished by a pervasive system of deep erosional troughs and sharp ridges thought to have been glacially sculpted by the Hellas Lobe. It is concluded that glaciation in Hellas occurred during the Middle Amazonian, roughly coeval with glaciation in Argyre.

Johnson, N.↗
NASA NTRS1986

Continuous, Multielement, Hot-Film Transition Gage

Accurate measurement of location where laminar boundary layer undergoes transition to turbulent one serves many purposes in basic aero-dynamic research and developmental testing. Individual gages must be staggered to prevent formation of turbulence at gages downstream. This arrangement precludes accurate measurements of laminar/turbulent transition regions along streamline. Complete understanding of performance, stability, and control of laminar-flow airplane requires knowledge of transition locations on wing surface, empennage surfaces, fuselage, and nacelles. Visual, acoustic, and electronic methods capable of providing this transition information.

Holmes, B.↗
NASA NTRS1984

The historical development and basis of human factors guidelines for automated systems in aeronautical operations

In order to derive general design guidelines for automated systems a study was conducted on the utilization and acceptance of existing automated systems as currently employed in several commercial fields. Four principal study area were investigated by means of structured interviews, and in some cases questionnaires. The study areas were aviation, a both scheduled airline and general commercial aviation; process control and factory applications; office automation; and automation in the power industry. The results of over eighty structured interviews were analyzed and responses categoried as various human factors issues for use by both designers and users of automated equipment. These guidelines address such items as general physical features of automated equipment; personnel orientation, acceptance, and training; and both personnel and system reliability.

Ciciora, J. A.↗
NASA NTRS1979

Solar power conditioner

Efficient power-conditioning circuit designed to utilize maximum power available from solar cell array, controls output of array so that excess energy not needed by load is diverted to charge batteries for reserve power when sufficient sunlight is not available.

Jan, L.↗