ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Books  (34)
  • Other Sources  (29)
Collection
Language
Branch Library
  • 11
    Publication Date: 2019-07-13
    Description: Biosphere-atmosphere water and carbon fluxes depend on ecosystem structure, and their magnitudes and seasonal behavior are driven by environmental and biological factors. We studied the seasonal behavior of net ecosystem CO2 exchange (NEE), Gross Primary Productivity (GPP), Ecosystem Respiration (RE), and actual evapotranspiration (ETa) obtained by eddy covariance measurements during two years in a Mediterranean Acacia savanna ecosystem (Acacia caven) in Central Chile. The annual carbon balance was 53 g C/sq. m in 2011 and 111 g C/sq. m in 2012, showing that the ecosystem acts as a net sink of CO2, notwithstanding water limitations on photosynthesis observed in this particularly dry period. Total annual ETa was of 128 mm in 2011 and 139 mm in 2012. Both NEE and ETa exhibited strong seasonality with peak values recorded in the winter season (July to September), as a result of ecosystem phenology, soil water content and rainfall occurrence. Consequently, the maximum carbon assimilation rate occurred in wintertime. Results show that soil water content is a major driver of GPP and RE, defining their seasonal patterns and the annual carbon assimilation capacity of the ecosystem, and also modulating the effect that solar radiation and air temperature have on NEE components at shorter time scales.
    Keywords: Meteorology and Climatology
    Type: GSFC-E-DAA-TN58017 , Scientific Reports (e-ISSN 2045-2322); 8; 8570
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2019-07-13
    Description: Objective: To innovate sandphobic coating and surface modification for high temperature turbine blades to resist sand glaze build-up and related Calcia-Magnesia-Alumina-Silicate (CMAS) attack on Thermal/Environmental Barrier Coatings (T/EBCs).
    Keywords: Aircraft Propulsion and Power
    Type: GRC-E-DAA-TN52258 , Annual Conference and Expo on Advanced Ceramics and Composites; Jan 22, 2018 - Jan 25, 2018; Cocoa Beach, FL; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Publication Date: 2019-07-18
    Description: No abstract available
    Keywords: Man/System Technology and Life Support
    Type: MSFC-E-DAA-TN70408 , International Conference on Environmental Systems; Jul 07, 2019 - Jul 11, 2019; Boston, MA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Publication Date: 2019-07-27
    Description: Historically, competitions and prizes such as those executed by the NASA Centennial Challenges (CC) program have created broader avenues through which to spur innovation from unlikely sources. In 2005, Congress amended the National Aeronautics and Space Act of 1958 to authorize NASA to create challenges through which prizes could be awarded to United States citizens or entities that succeeded in meeting the challenge objectives. Over the past 13 years, the CC program has initiated more than 19 challenges in a variety of technology areas, including propulsion, robotics, communications and navigation, human health, science instrumentation, nanotech, materials/structures and aerodynamics. This paper will discuss the status and the accomplishments of the CC program and discuss results of an ideation process designed to identify and formulate topics for a potential Centennial Challenge competition targeting a life support technology gap for future long-term exploration missions. Status of this challenge formulation process with information on how to use crowdsourcing tools will be discussed. An overview of the CC Programs accomplishments, including strategic objectives, past challenges, and current challenge development and execution. This program exemplifies the values that have formed the bedrock of the culture at NASA since the beginning: innovation, imagination, and a passion for exploration.
    Keywords: Man/System Technology and Life Support
    Type: MSFC-E-DAA-TN68902 , International Conference on Environmental Systems; Jul 07, 2019 - Jul 11, 2019; Boston, MA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Publication Date: 2019-07-12
    Description: Multiparallel three-dimensional optical microscopy is a method of forming an approximate three-dimensional image of a microscope sample as a collection of images from different depths through the sample. The imaging apparatus includes a single microscope plus an assembly of beam splitters and mirrors that divide the output of the microscope into multiple channels. An imaging array of photodetectors in each channel is located at a different distance along the optical path from the microscope, corresponding to a focal plane at a different depth within the sample. The optical path leading to each photodetector array also includes lenses to compensate for the variation of magnification with distance so that the images ultimately formed on all the photodetector arrays are of the same magnification. The use of optical components common to multiple channels in a simple geometry makes it possible to obtain high light-transmission efficiency with an optically and mechanically simple assembly. In addition, because images can be read out simultaneously from all the photodetector arrays, the apparatus can support three-dimensional imaging at a high scanning rate.
    Keywords: Instrumentation and Photography
    Type: MSC-23851-1 , NASA Tech Briefs, January 2010; 31
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2019-08-17
    Description: One of the research groups at the Pan American Center for Earth and Environmental Studies (PACES) is researching the northward migration path of Africanized Honey Bees or often referred to in the popular press as killer bees. The goal of the Killer Bee Research Group (KBRG) is to set up a database in the form of a geographical information system, which will be used to track and predict the bees future migration path. Included in this paper is background information on geographical information systems, the SPANS Explorer software package which was used to implement the database, and Advanced Very High Resolution Radiometer data and how each of these is being incorporated in the research. With an accurate means of predicting future migration paths, the negative effects of the Africanized honey bees maybe reduced.
    Keywords: Life Sciences (General)
    Type: URC97133 , NASA University Research Centers Technical Advances in Education, Aeronautics, Space, Autonomy, Earth and Environment; 1; 779-783
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Publication Date: 2019-08-28
    Description: Information on the use of LANDSAT data by Argentina is presented. Details on a Swedish satellite to be completed in 1984 and to be called VIKING are reported. Attempts to contact other civilizations in space by the use of radiotelescopes are discussed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Type: NASA-TM-76477
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Publication Date: 2019-07-13
    Description: Gas turbine engines for military/commercial fixed-wing and rotary wing aircraft use thermal barrier coatings in the high-temperature sections of the engine for improved efficiency and power. The desire to further make improvements in gas turbine engine efficiency and high power-density is driving the research and development of thermal barrier coatings and the effort of improving their tolerance to fine foreign particulates that may be contained in the intake air. Both commercial and military aircraft engines often are required to operate over sandy regions such as in the Middle-East nations, as well as over volcanic zones. For rotorcraft gas turbine engines, the sand ingestion is adverse during take-off, hovering near ground, and landing conditions. Although, most of the rotorcraft gas turbine engines are fitted with inlet particle separators, they are not 100 percent efficient in filtering fine sand particles of size 75 microns or below. The presence of these fine solid particles in the working fluid medium has an adverse effect on the durability of turbine blade thermal barrier coatings and overall performance of the engine. Typical turbine blade damages include blade coating wear, sand glazing, Calcia-Magnesia-Alumina-Silicate (CMAS) attack, oxidation, plugged cooling holes, all of which can cause rapid performance deterioration including loss of aircraft. The objective of this research is to understand the fine particle interactions with typical ceramic coatings of turbine blades at the microstructure level. A finite-element based microstructure modeling and analysis has been performed to investigate particle-surface interactions, and restitution characteristics. Experimentally, a set of tailored thermal barrier coatings and surface treatments were down-selected through hot burner rig tests and then applied to first stage nozzle vanes of the Gas Generator Turbine of a typical rotorcraft gas turbine engine. Laser Doppler velocity measurements were performed during hot burner rig testing to determine sand particle incoming velocities and their rebound characteristics upon impact on coated material targets. Further, engine sand ingestion tests were carried out to test the CMAS tolerance of the coated nozzle vanes. The findings from this on-going collaborative research to develop the next-gen sand tolerant coatings for turbine blades are presented in this paper.
    Keywords: Aircraft Propulsion and Power; Mechanical Engineering; Composite Materials
    Type: ASME Paper GT2017-64051 , GRC-E-DAA-TN39630 , Proceedings of ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition; 2D: Turbomachinery; V02DT48A009|Turbo Expo: ASME 2017 Turbomachinery Technical Conference & Exposition; Jun 26, 2017 - Jun 30, 2017; Charlotte, NC; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Publication Date: 2019-07-17
    Description: Here we discuss the effect that the emergence of flux with a polarity opposed to that previously established in a certain photospheric region. can have on the magnetic structure of the solar atmosphere. We show that such a flux emergence may lead to the ejection of coronal material into the interplanetary medium (a CME) and also to a rapid change in the velocity of the solar wind from the region, which may eventually lead to the formation of an interplanetary shock.
    Keywords: Astrophysics
    Type: ; 59
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Publication Date: 2019-07-13
    Description: The six sensors of SEIS (The Seismic Experiment for Interior Structure) [- one of three primary instruments on NASA's Mars Lander Insight] cover a broad range of the seismic bandwidth, from 0.01 hertz to 50 hertz, with possible extension to longer periods. Data are transmitted in the form of three continuous VBB (Very Broad-Band) components at 2 samples per second (sps), an estimation of the short period (SP) energy content from the SP at 1 sps, and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams are augmented by requested event data with sample rates from 20 to 100 sps. SEIS data products are downlinked from the spacecraft in raw CCSDS (Consultative Committee for Space Data Systems) packets and converted to both the Standard for the Exchange of Earthquake Data (SEED) format files and ASCII tables (GeoCSV) for analysis and archiving. Metadata are available in dataless SEED and StionXML. Time series data (waveforms) are available in miniseed and GeoCSV. Data are distributed according to FDSN (Federation of Digital Seismograph Networks - http://www.fdsn.org) formats and interfaces. Wind, pressure and temperature data from the Auxiliary Payload Sensor Suite (APSS) will also be available in SEED format, and can be used for decorrelation and diagnostic purposes on SEIS.
    Keywords: Geophysics; Lunar and Planetary Science and Exploration
    Type: MSFC-E-DAA-TN67833 , Seismological Society of America Annual Meeting (SSA 2019); Apr 23, 2019 - Apr 26, 2019; Seattle, WA; United States
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...