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Sample records for al atmos environ

  1. Web portal on environmental sciences "ATMOS''

    NASA Astrophysics Data System (ADS)

    Gordov, E. P.; Lykosov, V. N.; Fazliev, A. Z.

    2006-06-01

    The developed under INTAS grant web portal ATMOS (http://atmos.iao.ru and http://atmos.scert.ru) makes available to the international research community, environmental managers, and the interested public, a bilingual information source for the domain of Atmospheric Physics and Chemistry, and the related application domain of air quality assessment and management. It offers access to integrated thematic information, experimental data, analytical tools and models, case studies, and related information and educational resources compiled, structured, and edited by the partners into a coherent and consistent thematic information resource. While offering the usual components of a thematic site such as link collections, user group registration, discussion forum, news section etc., the site is distinguished by its scientific information services and tools: on-line models and analytical tools, and data collections and case studies together with tutorial material. The portal is organized as a set of interrelated scientific sites, which addressed basic branches of Atmospheric Sciences and Climate Modeling as well as the applied domains of Air Quality Assessment and Management, Modeling, and Environmental Impact Assessment. Each scientific site is open for external access information-computational system realized by means of Internet technologies. The main basic science topics are devoted to Atmospheric Chemistry, Atmospheric Spectroscopy and Radiation, Atmospheric Aerosols, Atmospheric Dynamics and Atmospheric Models, including climate models. The portal ATMOS reflects current tendency of Environmental Sciences transformation into exact (quantitative) sciences and is quite effective example of modern Information Technologies and Environmental Sciences integration. It makes the portal both an auxiliary instrument to support interdisciplinary projects of regional environment and extensive educational resource in this important domain.

  2. Advanced Multimission Operations System (ATMO)

    NASA Technical Reports Server (NTRS)

    Mandrake, Lucas; Thompson, David R.

    2013-01-01

    The HiiHat toolbox developed for CAT/ENVI provides principal investigators direct, immediate, flexible, and seamless interaction with their instruments and data from any location. Offering segmentation and neutral region division, it facilitates the discovery of key endmembers and regions of interest larger than a single pixel. Crucial to the analysis of hyperspectral data from Mars or Earth is the removal of unwanted atmospheric signatures. For Mars and the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), residual atmospheric CO2 absorption is both directly problematic and indicative of processing errors with implications to the scientific utility of any particular image region. Estimating this residual error becomes key both in selecting regions of low distortion, and also to select mitigating methods, such as neutral region division. This innovation, the ATMO estimator, provides a simple, 0-1 normalized scalar that estimates this distortion (see figure). The metric is defined as the coefficient of determination of a quadratic fit in the region of distorting atmospheric absorption (approx 2 micron). This mimics the behavior of existing CRISM team mineralogical indices to estimate the presence of known, interesting mineral signatures. This facilitates the ATMO metric's assimilation into existing planetary geology workflows.

  3. 77 FR 15748 - Atmos Energy Corporation/Atmos Energy-Kentucky/Mid-States Division; Notice of Motion for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-16

    ... of Motion for Extension of Rate Case Filing Deadline Take notice that on March 9, 2012, Atmos Energy Corporation filed on behalf of Atmos Energy--Kentucky/Mid-States Division (Atmos) a motion requesting an... a motion to intervene or to protest this filing must file in accordance with Rules 211 and 214...

  4. U-ALS: A Ubiquitous Learning Environment

    ERIC Educational Resources Information Center

    Piovesan, Sandra Dutra; Passerino, Liliana Maria; Medina, Roseclea Duarte

    2012-01-01

    The diffusion of the use of the learning virtual environments presents a great potential for the development of an application which meet the necessities in the education area. In view of the importance of a more dynamic application and that can adapt itself continuously to the students' necessities, the "U-ALS" (Ubiquitous Adapted Learning…

  5. Predicting the thermal/structural performance of the atmospheric trace molecules spectroscopy /ATMOS/ Fourier transform spectrometer

    NASA Technical Reports Server (NTRS)

    Miller, J. M.

    1980-01-01

    ATMOS is a Fourier transform spectrometer to measure atmospheric trace molecules over a spectral range of 2-16 microns. Assessment of the system performance of ATMOS includes evaluations of optical system errors induced by thermal and structural effects. In order to assess the optical system errors induced from thermal and structural effects, error budgets are assembled during system engineering tasks and line of sight and wavefront deformations predictions (using operational thermal and vibration environments and computer models) are subsequently compared to the error budgets. This paper discusses the thermal/structural error budgets, modelling and analysis methods used to predict thermal/structural induced errors and the comparisons that show that predictions are within the error budgets.

  6. Orbital analysis for atmospheric trace molecule spectroscopy (ATMOS) Shuttle missions

    NASA Technical Reports Server (NTRS)

    Harrison, Edwin F.; Denn, Frederick M.; Gibson, Gary G.

    1988-01-01

    An orbital analysis was carried out to define the geographical coverage capabilities of an ATMOS solar occultation experiment on Space Shuttle/Spacelab missions. Particular attention was given to the effects of launch time, orbit inclination, altitude, and season on latitude-longitude coverage. It is shown that the widest band of latitude coverage in the tropics and temperate zones can be achieved with a midinclined orbit and a midmorning or late-night launch time. The use of ATMOS Shuttle underflights to provide coincident measurements with a solar occultation experiment on the Upper Atmospheric Research Satellite is also examined.

  7. 78 FR 39720 - Atmos Pipeline and Storage, LLC; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Atmos Pipeline and Storage, LLC; Notice of Application Take notice that on June 14, 2013, Atmos Pipeline and Storage, LLC. (Atmos), filed with the Federal Energy Regulatory Commission an application under section 7(b)...

  8. 77 FR 21760 - Atmos Energy Colorado/Kansas Division; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-11

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Atmos Energy Colorado/Kansas Division; Notice of Baseline Filing Take notice that on March 30, 2012, Atmos Energy Colorado/Kansas Division (Atmos) submitted a baseline...

  9. 77 FR 23244 - Atmos Energy Colorado/Kansas Division; Notice of Revised Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Atmos Energy Colorado/Kansas Division; Notice of Revised Baseline Filing Take notice that on April 10, 2012, Atmos Energy Colorado/Kansas Division (Atmos) filed a...

  10. ATMOS: Long term atmospheric measurements for mission to planet Earth

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A long-term, space-based measurement program, together with continued balloon and aircraft-borne investigations, is essential to monitor the predicted effects in the atmosphere, to determine to what extent the concentration measurements agree with current models of stratospheric chemistry, and to determine the condition of the ozone layer. The Atmospheric Trace Molecule Spectroscopy (ATMOS) Experiment is currently making comprehensive, global measurements of Earth's atmosphere as part of the Atmospheric Laboratory for Applications and Science (ATLAS) program on the Space Shuttle. Part of NASA's Mission to Planet Earth, ATLAS is a continuing series of missions to study Earth and the Sun and provide a more fundamental understanding of the solar influences on Earth's atmosphere. The ATMOS program, instruments, and science results are presented.

  11. [The ATMO index: an air quality indicator for developed areas in France].

    PubMed

    2003-05-01

    The LAURE (5) of 30 december, 1996, sets the preventive, monitoring, reduction or suppression of atmospheric pollution objectives and the goals for preserving air quality. Heading 1--Article 4 of the law states in particular that the right to information on air quality and its impact on the environment is recognised as the right of every person on French territory. The decree of 10 january, 2000, about the air-quality index is derived from this determination to information for all, stated as an important element in the policy for air-quality management. This decree provides definitions of the ATMO index with "standards 2000" and the recommendations required for its calculation. Previously (1992 and before), certain local agencies had developed their own index. Naturally these indices showed sizeable differences. The effort provided by the Ministry of the Environment, ADEME and the monitoring agencies, enabled the definition of a single index for the whole of the large urban areas (> 100,000 inhabitants). The index gives a common language to the non-specialist public, which can now understand the overall air quality in different urban areas. As all aggregate indicators of the same kind, the ATMO index is designed as a tool that makes it possible to translate in a quantitative and simple way the synthesis of numerous measurement data recorded daily by official air-quality monitoring agencies (AASQA). PMID:12838780

  12. Heavy ozone enrichments from ATMOS infrared solar spectra

    NASA Astrophysics Data System (ADS)

    Irion, F. W.; Gunson, M. R.; Rinsland, C. P.; Yung, Y. L.; Abrams, M. C.; Chang, A. Y.; Goldman, A.

    Vertical enrichment profiles of stratospheric 16O16Ol8O and 16O18O16O (hereafter referred to as 668O3 and 686O3 respectively) have been derived from space-based solar occultation spectra recorded at 0.01 cm-1 resolution by the ATMOS (Atmospheric Trace MOlecule Spectroscopy) Fourier-transform infrared (FTIR) spectrometer. The observations, made during the Spacelab 3 and ATLAS-1, -2, and -3 shuttle missions, cover polar, mid-latitude and tropical regions between 26 to 2.6 mb inclusive (≈ 25 to 41 km). Average enrichments, weighted by molecular 48O3 density, of (15±6)% were found for 668O3 and (10±7)% for 686O3. Defining the mixing ratio of 50O3 as the sum of those for 668O3 and 686O3, an enrichment of (13±5)% was found for 50O3 (1σ standard deviation). No latitudinal or vertical gradients were found outside this standard deviation. From a series of ground-based measurements by the ATMOS instrument at Table Mountain, California (34.4°N), an average total column 668O3 enrichment of (17±4)% (1σ standard deviation) was determined, with no significant seasonal variation discernable. Possible biases in the spectral intensities that affect the determination of absolute enrichments are discussed.

  13. Optical design of the ATMOS Fourier transform spectrometer

    NASA Technical Reports Server (NTRS)

    Abel, I. R.; Reynolds, B. R.; Breckinridge, J. B.; Pritchard, J.

    1979-01-01

    The optical system design of the ATMOS Fourier transform spectrometer to be operated from Spacelab for the measurement of stratospheric trace molecules is described. The design contains features which can achieve the required fringe contrast of 80% and spectral resolution of 0.02/cm over a spectral range of 2-16 microns. In particular, the design is based on the following features which alleviate the usual requirements for alignment precision: (1) 'cat's eye' mirror configuration in the two arms of the interferometer for retroreflection stability, (2) tilt-compensated system of beamsplitter, compensator, and fold mirrors for wavefront directional stability, (3) paraboloidal 'cat's eye' primary mirror for wavefront stability against shear, (4) rotatable compensator for matching chromatic dispersion, and (5) wedged refractive components to avoid channel spectra due to the Fabry-Perot effect.

  14. 75 FR 31429 - Atmos Pipeline-Texas; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-03

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Atmos Pipeline--Texas; Notice of Baseline Filing May 27, 2010. Take notice that on May 27, 2010, Atmos Pipeline--Texas submitted a baseline filing of its Statement of...

  15. Stratospheric infrared continuum absorptions observed by the ATMOS instrument

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Zander, R.; Namkung, J. S.; Farmer, C. B.; Norton, R. H.

    1989-01-01

    A quantitative analysis of infrared continuum absorption features observed in ATMOS/Spacelab 3 (1985) spectra of the lower stratosphere is reported. Continuous absorption produced primarily by the collision-induced fundamental vibration-rotation band of O2 and to a lesser extent by the superposition of H2O far line wings has been observed in the 1400 to 1800/cm interval below tangent heights of about 25 km. Continuum optical depths measured in microwindows nearly free of atmospheric line absorption are 0.78 + or - 0.06 times those calculated with the O2 absorption coefficients of Timofeyev and Tonkov (1978). Transmittance measurements in microwindows between 2395 and 2535/cm have been used to study continuous absorption from the collision induced fundamental vibration-rotation band of N2 and the far wings of strong CO2 lines. The measured transmittances have been analyzed to derive best fit absorption coefficients for the N2 pressure-induced band at lower stratospheric temperatures (about 210 K).

  16. Validation environment for AIPS/ALS: Implementation and results

    NASA Technical Reports Server (NTRS)

    Segall, Zary; Siewiorek, Daniel; Caplan, Eddie; Chung, Alan; Czeck, Edward; Vrsalovic, Dalibor

    1990-01-01

    The work is presented which was performed in porting the Fault Injection-based Automated Testing (FIAT) and Programming and Instrumentation Environments (PIE) validation tools, to the Advanced Information Processing System (AIPS) in the context of the Ada Language System (ALS) application, as well as an initial fault free validation of the available AIPS system. The PIE components implemented on AIPS provide the monitoring mechanisms required for validation. These mechanisms represent a substantial portion of the FIAT system. Moreover, these are required for the implementation of the FIAT environment on AIPS. Using these components, an initial fault free validation of the AIPS system was performed. The implementation is described of the FIAT/PIE system, configured for fault free validation of the AIPS fault tolerant computer system. The PIE components were modified to support the Ada language. A special purpose AIPS/Ada runtime monitoring and data collection was implemented. A number of initial Ada programs running on the PIE/AIPS system were implemented. The instrumentation of the Ada programs was accomplished automatically inside the PIE programming environment. PIE's on-line graphical views show vividly and accurately the performance characteristics of Ada programs, AIPS kernel and the application's interaction with the AIPS kernel. The data collection mechanisms were written in a high level language, Ada, and provide a high degree of flexibility for implementation under various system conditions.

  17. A Comparison of Measurements from ATMOS and Instruments Aboard the ER-2 Aircraft: Halogenated Gases

    NASA Technical Reports Server (NTRS)

    Chang, A. Y.; Salawitch, R. J.; Michelsen, H. A.; Gunson, M. R.; Abrams, M. C.; Zander, R.; Rinsland, C. P.; Elkins, J. W.; Dutton, G. S.; Volk, C. M.; Webster, C. R.; May, R. D.; Fahey, D. W.; Gao, R.-S.; Loewenstein, M.

    1996-01-01

    We compare volume mixing ratio profiles of N2O, CFC-11, CFC-12, CCl4, SF6, and HCl in the mid-latitude lower stratosphere measured by the ATMOS Fourier transform spectrometer on the ATLAS-3 Space Shuttle Mission with in situ measurements acquired from the NASA ER-2 aircraft during Nov. 1994. Good agreement is found between ATMOS and in situ correlations of [CFC-11], [CFC-12], and [SF6] with [N2O]. ATMOS measurements of [CCl4] are 15% high compared to ER-2 data, but agree within the systematic uncertainties. ATMOS observations of [HCl] vs [N2O] are within approximately 10% of ER-2 data for [HCl] > 1 ppbv, but exceed in situ measurements by larger fractional amounts for smaller [HCl]. ATMOS measurements of [ClONO2] agree well with values inferred from in situ observations of [ClO], [NO], and [O3]. The sum of [HCl] and [ClONO2] observed by ATMOS, supplemented by a minor contribution from [ClO] estimated with a photochemical model, is consistent with the levels of inorganic chlorine inferred from in situ measurements of chlorine source gases.

  18. The Atmospheric Trace Molecule Spectroscopy (ATMOS) Experiment: Deployment on the ATLAS Space Shuttle Missions

    NASA Technical Reports Server (NTRS)

    Gunson, M. R.; Abbas, M. M.; Abrams, M. C.; Allen, M.; Brown, L. R.; Brown, T. L.; Chang, A. Y.; Goldman, A.; Irion, F. W.; Lowes, L. L..; Mahieu, E.; Manney, G. L.; Michelsen, H. A.; Newchurch, M. J.; Rinsland, C. P.; Salawitch, R. J.; Stiller, G. P.; Toon, G. C.; Yung, Y. L.; Zander, R.

    1996-01-01

    The ATMOS Fourier transform spectrometer was flown for a fourth time on the Space Shuttle as part of the ATLAS-3 instrument payload in November 1994. More than 190 sunrise and sunset occultation events provided measurements of more than 30 atmospheric trace gases at latitudes 3 - 49 deg N and 65 - 72 deg S, including observations both inside and outside the Antarctic polar vortex. The instrument configuration, data retrieval methodology, and mission background are described to place in context analyses of ATMOS data presented in this issue.

  19. The ATMOS (Atmospheric Trace MOlecule Spectroscopy) experiment - A tool for global monitoring of the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Zander, R.; Gunson, M. R.; Farmer, C. B.; Norton, R. H.; Rinsland, C. P.

    1990-01-01

    A review is presented of the objectives, instrumentation, performance and results of the ATMOS program developed by NASA-JPL as part of the Spacelab 3 shuttle payload. ATMOS was developed to obtain high-resolution spectroscopic information of the middle atmosphere, from which the vertical distribution of the most possible trace and minor molecules could be retrieved. A complete occultation included not only data recorded when the optical path traversed the earth's atmosphere, but also many spectra with tangent heights big enough for no more telluric absorptions to be detected. The averaging of such 'high sun' observations has provided high quality solar spectra totally free of atmospheric absorption features.

  20. Automated CO2 extraction from air for clumped isotope analysis in the atmo- and biosphere

    NASA Astrophysics Data System (ADS)

    Hofmann, Magdalena; Ziegler, Martin; Pons, Thijs; Lourens, Lucas; Röckmann, Thomas

    2015-04-01

    The conventional stable isotope ratios 13C/12C and 18O/16O in atmospheric CO2 are a powerful tool for unraveling the global carbon cycle. In recent years, it has been suggested that the abundance of the very rare isotopologue 13C18O16O on m/z 47 might be a promising tracer to complement conventional stable isotope analysis of atmospheric CO2 [Affek and Eiler, 2006; Affek et al. 2007; Eiler and Schauble, 2004; Yeung et al., 2009]. Here we present an automated analytical system that is designed for clumped isotope analysis of atmo- and biospheric CO2. The carbon dioxide gas is quantitatively extracted from about 1.5L of air (ATP). The automated stainless steel extraction and purification line consists of three main components: (i) a drying unit (a magnesium perchlorate unit and a cryogenic water trap), (ii) two CO2 traps cooled with liquid nitrogen [Werner et al., 2001] and (iii) a GC column packed with Porapak Q that can be cooled with liquid nitrogen to -30°C during purification and heated up to 230°C in-between two extraction runs. After CO2 extraction and purification, the CO2 is automatically transferred to the mass spectrometer. Mass spectrometric analysis of the 13C18O16O abundance is carried out in dual inlet mode on a MAT 253 mass spectrometer. Each analysis generally consists of 80 change-over-cycles. Three additional Faraday cups were added to the mass spectrometer for simultaneous analysis of the mass-to-charge ratios 44, 45, 46, 47, 48 and 49. The reproducibility for δ13C, δ18O and Δ47 for repeated CO2 extractions from air is in the range of 0.11o (SD), 0.18o (SD) and 0.02 (SD)o respectively. This automated CO2 extraction and purification system will be used to analyse the clumped isotopic signature in atmospheric CO2 (tall tower, Cabauw, Netherlands) and to study the clumped isotopic fractionation during photosynthesis (leaf chamber experiments) and soil respiration. References Affek, H. P., Xu, X. & Eiler, J. M., Geochim. Cosmochim. Acta 71, 5033

  1. ALS: A bucket of genes, environment, metabolism and unknown ingredients.

    PubMed

    Zufiría, Mónica; Gil-Bea, Francisco Javier; Fernández-Torrón, Roberto; Poza, Juan José; Muñoz-Blanco, Jose Luis; Rojas-García, Ricard; Riancho, Javier; de Munain, Adolfo López

    2016-07-01

    The scientific scenario of amyotrophic lateral sclerosis (ALS) has dramatically changed since TDP-43 aggregates were discovered in 2006 as the main component of the neuronal inclusions seen in the disease, and more recently, when the implication of C9ORF72 expansion in familial and sporadic cases of ALS and frontotemporal dementia was confirmed. These discoveries have enlarged an extense list of genes implicated in different cellular processes such as RNA processing or autophagia among others and have broaden the putative molecular targets of the disease. Some of ALS-related genes such as TARDBP or SOD1 among others have important roles in the regulation of glucose and fatty acids metabolism, so that an impairment of fatty acids (FA) consumption and ketogenic deficits during exercise in ALS patients would connect the physiopathology with some of the more intriguing epidemiological traits of the disease. The current understanding of ALS as part of a continuum with other neurodegenerative diseases and a crossroads between genetic, neurometabolic and environmental factors represent a fascinating model of interaction that could be translated to other neurodegenerative diseases. In this review we summarize the most relevant data obtained in the ten last years and the key lines for future research in ALS. PMID:27236050

  2. Role of defect coordination environment on point defects formation energies in Ni-Al intermetallic alloys

    NASA Astrophysics Data System (ADS)

    Tennessen, Emrys; Rondinelli, James

    We present a relationship among the point defect formation energies and the bond strengths, lengths, and local coordination environment for Ni-Al intermetallic alloys based on density functional calculations, including Ni3Al, Ni5Al3, NiAl,Ni3Al4, Ni2Al3 and NiAl3. We find the energetic stability of vacancy and anti-site defects for the entire family can be attributed primarily to changes in interactions among first nearest neighbors, owing to spatially localized charge density reconstructions in the vicinity of the defect site. We also compare our interpretation of the local coordination environment with a DFT-based cluster expansion and discuss the performance of each approach in predicting defect stability in the Ni-Al system.

  3. Al3+ environments in nanostructured ZnAl2O4 and their effects on the luminescence properties.

    PubMed

    da Silva, Alison A; Gonçalves, Agnaldo S; Davolos, Marian R; Santagneli, Silvia H

    2008-11-01

    Single-phase zinc aluminate (ZnAl2O4) with the spinel structure was successfully obtained by the Pechini method at different calcining temperatures for 4 hours. The nanoparticles are highly crystalline with no impurities related to ZnO or Al2O3 residues. The microstructural environment of aluminium ions changes with heat treatment temperature, as observed by Fourier transform infrared spectroscopy. The spinel structure might present two different AlO6 sites as evidenced by 27Al solid-state magic-angle-spinning nuclear magnetic resonance spectra. Some AlO4 sites were also detected for samples calcined at a temperature lower than 900 degrees C. The photoluminescence spectra show that the emission can be tuned depending on the calcining temperature. This effect was discussed on the basis of symmetry and oxygen vacancies. PMID:19198290

  4. Profiles of Stratospheric Chlorine Nitrate from ATMOS/ATLAS 1 Infrared Solar Occultation Spectra

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Abrams, M. C.; Zander, R.; Mahieu, E.; Goldman, A.; Ko, M. K. W.; Rodriguez, J. M.; Sze, N. D.

    1994-01-01

    Stratospheric volume mixing ration profiles of chlorine nitrate have been retrieved from 0.01-cm(sub -1) resolution infrared solar occutation spectra recorded at latitudes between 14 degrees N and 54 degrees S by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the ATLAS 1 shuttle mission (March 24 to April 2, 1992).

  5. Identification of tetrahedrally ordered Si-O-Al environments in molecular sieves by { 27Al}- 29Si REAPDOR NMR

    NASA Astrophysics Data System (ADS)

    Ganapathy, S.; Kumar, Rajiv; Montouillout, V.; Fernandez, C.; Amoureux, J. P.

    2004-05-01

    The silicon sites tetrahedrally connected to aluminum in framework positions of a molecular sieve may be identified by a selective reintroduction of the hetero-nuclear 27Al- 29Si dipolar interaction through Rotational Echo Adiabatic Passage DOuble Resonance (REAPDOR) NMR. In this rotor synchronized 29Si MAS experiment, an effective dipolar dephasing of the Si-O-Al, over Si-O-Si, environments is shown to aid in the identification of silicon sites in the immediate vicinity of aluminum. Application of the method in the structurally interesting and novel molecular sieve ETAS-10 provides valuable insights on the details of aluminum substitution in the zeolite lattice and further leads to the first direct NMR estimate of Al-Si distance ( rAl-Si=323±5 pm) in ETAS-10.

  6. What do the cited and citing environments reveal about Advances in Atmospheric Physics?

    NASA Astrophysics Data System (ADS)

    Shi, Aolan; Leydesdorff, Loet

    2011-01-01

    The networking status of journals reflects their academic influence among peer journals. This paper analyzes the cited and citing environments of this journal, Advances in Atmospheric Sciences ( Adv. Atmos. Sci.), using methods from social network analysis. Since its initial publication, Adv. Atmos. Sci. has been actively participating in the international journal environment and international journals are frequently cited in Adv. Atmos. Sci. Particularly, this journal is intensely interrelated with its international peer journals in terms of their similar citing patterns. The international influence of Adv. Atmos. Sci. is comparatively bigger than other Chinese SCI journals in atmospheric sciences as reflected by total cites to Adv. Atmos. Sci. and the total number of international journals citing it. The academic visibility of Adv. Atmos. Sci. is continuing to improve in the international research community as the number of reference citation it receives in its peer journals internationally increases over time.

  7. The influence of growth speed, orientation and environment on fracture of aligned Al-CuAl2

    NASA Technical Reports Server (NTRS)

    Skiff, P. K.; Stoloff, N. S.

    1977-01-01

    There has been considerable interest in the mechanical properties of aligned eutectics as functions of microstructure, orientation between reinforcement and stress axis, and temperature of testing. However, little is known about the behavior of these alloys in aggressive environments, such as liquid metals, with the exception of a recent paper on embrittlement of several eutectic alloys in gallium and gallium-indium alloys. This paper is concerned with the effects of a liquid Ga-16%In solution on tensile behavior of an aligned Al-CuAl2 eutectic.

  8. Trace Gas Transport in the Arctic Vortex Inferred from ATMOS ATLAS-2 Observations During April 1993

    NASA Technical Reports Server (NTRS)

    Abrams, M. C.; Manney, G. L.; Gunson, M. R.; Abbas, M. M.; Chang, A. Y.; Goldman, A.; Irion, F. W.; Michelsen, H. A.; Newchurch, M. J.; Rinsland, C, P,; Salawitch, R. J.; Stiller, G. P.; Zander, R.

    1996-01-01

    Measurements of the long-lived tracers CH4, N2O, and HF from the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument during the Atmospheric Laboratory for Science and Applications-2 (ATLAS-2) Space Shuttle mission in April 1993 are used to infer average winter descent rates ranging from 0.8 km/month at 20 km to 3.2 km/month at 40 km in the Arctic polar vortex during the 1992-93 winter. Descent rates in the mid-stratosphere are similar to those deduced for the Antarctic vortex using ATMOS/ATLAS-3 measurements in November 1994, but the shorter time period of descent in the Arctic leads to smaller total distances of descent. Strong horizontal gradients observed along the vortex edge indicate that the Arctic vortex remains a significant barrier to transport at least until mid-April in the lower to middle stratosphere.

  9. Measurement of atmospheric composition by the ATMOS instrument from Table Mountain Observatory

    NASA Astrophysics Data System (ADS)

    Gunson, Michael R.; Irion, Fredrick W.

    1991-09-01

    Following its first flight on board the Space Shuttle 'Challenger' as part of the Spacelab 3 payload, the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument has been operated at the Jet Propulsion Laboratory's Table Mountain Observatory (TMO; 34.4 deg N, 117.7 deg W, 2.23 km altitude) in the San Gabriel Mountains of Southern California. With the delay in the resumption of regular Shuttle flights, ATMOS has acquired a large number of high-quality, high-resolution infrared solar absorption spectra, spanning a period between late-1985 and mid-1990. These spectra are being analyzed to derive the column abundances of several atmospheric species including O3, HCl, HF, and HNO3. Although limited in temporal coverage, the preliminary results for these gases are discussed here in the context of the requirement and contribution to be made by similar instruments in detecting long term changes in stratospheric composition.

  10. Increase of Stratospheric Carbon Tetrafluoride (CF4) Based on ATMOS Observations from Space

    NASA Technical Reports Server (NTRS)

    Zander, R.; Solomon, S.; Mahieu, E.; Goldman, A.; Rinsland, C. P.; Gunson, M. R.; Abrams, M. C.; Chang, A. Y.; Michelsen, H. A.; Newchurch, M. J.; Stiller, G. P.

    1996-01-01

    Stratospheric volume mixing ratio profiles of carbon tetrafluoride, CF4, obtained with the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument during the ATLAS (Atmospheric Laboratory for Applications and Science) -3 mission of 1994 are reported. Overall the profiles are nearly constant over the altitude range 20 to 50 km, indicative of the very long lifetime of CF4 in the atmosphere. In comparison to the stratospheric values of CF4 inferred from the ATMOS/Spacelab 3 mission of 1985, the 1994 concentrations are consistent with an exponential increase of (1.6 +/- 0.6)% yr(exp -1). This increase is discussed with regard to previous results and likely sources of CF4 at the ground. Further, it is shown that simultaneous measurements of N2O and CF4 provide a means of constraining the lower limit of the atmospheric lifetime of CF4 at least 2,300 years, two sigma.

  11. Stratospheric sulfuric acid aerosols: composition and temperature discrimination with the ATMOS data set

    NASA Technical Reports Server (NTRS)

    Eldering, A.; Irion, F. W.; Mills, F. P.; Steele, H. M.; Kahn, B. H.; Gunson, M. R.

    2000-01-01

    The ATMOS Fourier transform spectrometer was flown for a fourth time on the Space Shuttle as part of the ATLAS-3 instrument payload in November 1994. More than 190 sunrise and sunset occultation events provided measurements of more than 30 atmospheric trace gases at latitudes 3-49(deg)N and 65-72(deg)S, including observations both inside and outside the Antarctic polar vortex.

  12. Synthetic Solar Spectra Out Of Atmos Data For The Near- And Mid-infrared Ranges

    NASA Astrophysics Data System (ADS)

    Seo, Haing Ja; Kim, S.; Kim, J.; Jang, M.

    2006-09-01

    We have constructed synthetic solar spectra for the 2.5 - 3.0 μm, 4.1 - 4.4 μm, and 5.1 - 7.7 μm ranges using Voigt line profiles, and with solar line identifications compiled by Geller (1992), who derived solar line positions and intensities from contaminated high-resolution solar spectra obtained by ATMOS (Atmospheric Trace Molecule Spectroscopy), a spaceborne observatory. Because the ATMOS spectra in these wavelength ranges are contaminated by absorption lines of molecules existing in Earth's high-altitude atmosphere, the direct use of this high-resolution solar spectra has been inconvenient for planetary scientists. We compared the synthetic solar spectra with the ATMOS spectra, and obtained satisfactory fits with the exception of a few abnormal lines. From the satisfactory comparisons, we were able to determine Voigt line parameters for each solar line. These synthetic solar spectra will be useful to eliminate solar continua from spectra of planetary objects to extract their own spectral characteristics. Reference Geller, M., 1992, A High-Resolution Atlas of the Infrared Spectrum of the Sun and the Earth Atmosphere from Space, Vol. III. Key to Identification of Solar Features, NASA Reference Pub. 1224.

  13. Stratospheric NO and NO2 Abundances from ATMOS Solar-Occultation Measurements

    NASA Technical Reports Server (NTRS)

    Newchurch, M. J.; Allen, M.; Gunson, M. R.; Salawitch, R. J.; Collins, G. B.; Huston, K. H.; Abbas, M. M.; Abrams, M. C.; Chang, A. Y.; Fahey, D. W.; Gao, R. S.; Irion, F. W.; Lowenstein, M.; Manney, G. L.; Michelsen, H. A.; Podolske, J. R.; Rinsland, C. P.; Zander, R.

    1996-01-01

    Using results from a time-dependent photochemical model to calculate the diurnal variation of NO and NO2, we have corrected Atmospheric Trace MOlecule Spectroscopy (ATMOS) solar-occultation retrievals of the NO and NO2 abundances at 90' solar zenith angle. Neglecting to adjust for the rapid variation of these gases across the terminator results in potential errors in retrieved profiles of approximately 20% for NO2 and greater than 100% for NC at altitudes below 25 km. Sensitivity analysis indicates that knowledge of the local 03 and temperature profiles, rather than zonal mean or climatological conditions of these quantities, is required to obtain reliable retrievals of NO and NO2 in the lower stratosphere. Extremely inaccurate 03 or temperature values at 20 km can result in 50% errors in retrieved NO or NO2. Mixing ratios of NO in the mid-latitude, lower stratosphere measured by ATMOS during the November 1994 ATLAS-3 mission compare favorably with in situ ER-2 observations, providing strong corroboration of the reliability of the adjusted space-borne measurements.

  14. ATMOS/ATLAS 3 Infrared Profile Measurements of Clouds in the Tropical and Subtropical Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Wang, P.-H.; Arduini, R. F.; Baum, B. A.; Minnis, P.; Goldman, A.; Abrams, M. C.; Zander, R.; Mahieu, E.; Salawitch, R. J.; Michelsen, H. A.; Irion, F. W.; Newchurch, M. J.

    1998-01-01

    Vertical profiles of infrared cirrus extinction have been derived from tropical and subtropical upper tropospheric solar occultation spectra. The measurements were recorded by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the Atmospheric Laboratory for Applications and Sciences (ATLAS) 3 shuttle flight in November 1994. The presence of large numbers of small ice crystals is inferred from the appearance of broad extinction features in the 8-12 micron region. These features were observed near the tropopause and at lower altitudes. Vertical profiles of the ice extinction (/km) in microwindows at 831, 957, and 1204/cm have been retrieved from the spectra and analyzed with a model for randomly oriented spheroidal ice crystals. An area-equivalent spherical radius of 6 microns is estimated from the smallest ice crystals observed in the 8-12 gm region. Direct penetration of clouds into the lower stratosphere is inferred from observations of cloud extinction extending from the upper troposphere to 50 mbar (20 km altitude). Cloud extinction between 3 and 5 microns shows very little wavelength dependence, at least for the cases observed by the ATMOS instrument in the tropics and subtropics during ATLAS 3.

  15. Atmos/Atlas 3 Infrared Profile Measurements of Clouds in the Tropical and Subtropical Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Wang, P.-H.; Arduini, R. F.; Baum, B. A.; Minnis, P.; Goldman, A.; Abrams, M. C.; Zander, R.; Mahieu, E.; Salawitch, R. J.; Michelsen, H. A.; Irions, F. W.; Newchurch, M. J.

    1998-01-01

    Vertical profiles of infrared cirrus extinction have been derived from tropical and subtropical upper tropospheric solar occultation spectra. The measurements were recorded by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the Atmospheric Laboratory for Applications and Sciences (ATLAS) 3 shuttle flight in November 1994. The presence of large numbers of small ice crystals is inferred from the appearance of broad extinction features in the 8-12 micron region. These features were observed near the tropopause and at lower altitudes. Vertical profiles of the ice extinction (/km) in microwindows at 831, 957, and 1204/cm have been retrieved from the spectra and analyzed with a model for randomly oriented spheroidal ice crystals. An area-equivalent spherical radius of 6 gm is estimated from the smallest ice crystals observed in the 8-12 micron region. Direct penetration of clouds into the lower stratosphere is inferred from observations of cloud extinction extending from the upper troposphere to 50 mbar (20 km altitude). Cloud extinction between 3 and 5 micron shows very little wavelength dependence, at least for the cases observed by the ATMOS instrument in the tropics and subtropics during ATLAS 3.

  16. AlGaAs/GaAs/AlGaAs quantum wells as a sensitive tool for the MOVPE reactor environment

    NASA Astrophysics Data System (ADS)

    Dimastrodonato, V.; Mereni, L. O.; Young, R. J.; Pelucchi, E.

    2010-10-01

    We present in this work a simple quantum well (QW) structure consisting of GaAs wells with AlGaAs barriers as a probe for measuring the performance of arsine purifiers within a metalorganic vapour phase epitaxy system. Comparisons between two different commercially available purifiers are based on the analysis of low-temperature photoluminescence emission spectra from thick QWs, grown on GaAs substrates misoriented slightly from (1 0 0). Neutral excitons emitted from these structures show extremely narrow linewidths, comparable with those that can be obtained by molecular beam epitaxy in an ultra-high vacuum environment, suggesting that purifications well below the 1 ppb level are needed to achieve high quality quantum well growth.

  17. Corrosion performance of Fe-Cr-Al and Fe aluminide alloys in complex gas environments

    SciTech Connect

    Natesan, K.; Johnson, R.N.

    1995-05-01

    Alumina-forming structural alloys can offer superior resistance to corrosion in the presence of sulfur-containing environments, which are prevalent in coal-fired fossil energy systems. Further, Fe aluminides are being developed for use as structural materials and/or cladding alloys in these systems. Extensive development has been in progress on Fe{sub 3}Al-based alloys to improve their engineering ductility. In addition, surface coatings of Fe aluminide are being developed to impart corrosion resistance to structural alloys. This paper describes results from an ongoing program that is evaluating the corrosion performance of alumina-forming structural alloys, Fe-Al and Fe aluminide bulk alloys, and Fe aluminide coatings in environments typical of coal-gasification and combustion atmospheres. Experiments were conducted at 650-1000{degrees}C in simulated oxygen/sulfur gas mixtures. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HCl-containing gases. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales and to determine the modes of corrosion degradation that occur in the materials when they are exposed to S/Cl-containing gaseous environments.

  18. Science applications of the multi-FOV lidar for ATMOS-B1/ERM

    NASA Astrophysics Data System (ADS)

    Sugimoto, Nobuo; Liu, Zhaoyan; Voelger, Peter; Shimizu, Atsushi; Sasano, Yasuhiro; Asai, Kazuhiro; Ishizu, Mitsuo; Itabe, Toshikasu; Imai, Tadashi

    2001-02-01

    A new multi-FOV space-borne lidar named "A-lidar" is being studied by the National Space Development Agency of Japan (NASDA) for the earth radiation mission proposed as a joint program with the European Space Agency (ESA). The mission is named "EarthCARE". It was formerly called ATMOS-B1 or ERM. The lidar has a two-wavelength transmitter (1064 nm and 532 nm), a dual polarization receiver at 1064 nm, and a multi-field-of-view (multi-FOV) receiver at 532 nm. The multi-FOV feature of A-lidar will enable us to solve the multiple scattering problems with space lidar measurements of profiles of clouds and aerosols. The multi-FOV feature can also be used for characterization of aerosols.

  19. The 1994 northern midlatitude budget of stratospheric chlorine derived from ATMOS/ATLAS-3 observations

    NASA Astrophysics Data System (ADS)

    Zander, R.; Mahieu, E.; Gunson, M. R.; Abrams, M. C.; Chang, A. Y.; Abbas, M.; Aellig, C.; Engel, A.; Goldman, A.; Irion, F. W.; Kämpfer, N.; Michelson, H. A.; Newchurch, M. J.; Rinsland, C. P.; Salawitch, R. J.; Stiller, G. P.; Toon, G. C.

    Volume mixing ratio (VMR) profiles of the chlorine-bearing gases HCl, ClONO2, CCl3F, CCl2F2, CHClF2, CCl4, and CH3Cl have been measured between 3 and 49° northern- and 65 to 72° southern latitudes with the Atmospheric Trace MOlecule Spectroscopy (ATMOS) instrument during the ATmospheric Laboratory for Applications and Science (ATLAS)-3 shuttle mission of 3 to 12 November 1994. A subset of these profiles obtained between 20 and 49°N at sunset, combined with ClO profiles measured by the Millimeter-wave Atmospheric Sounder (MAS) also from aboard ATLAS-3, measurements by balloon for HOCl, CH3CCl3 and C2Cl3F3, and model calculations for COClF indicates that the mean burden of chlorine, ClTOT, was equal to (3.53±0.10) ppbv (parts per billion by volume), 1-sigma, throughout the stratosphere at the time of the ATLAS 3 mission. This is some 37% larger than the mean 2.58 ppbv value measured by ATMOS within the same latitude zone during the Spacelab 3 flight of 29 April to 6 May 1985, consitent with an exponential growth rate of the chlorine loading in the stratosphere equal to 3.3%/yr or a linear increase of 0.10 ppbv/yr over the Spring-1985 to Fall-1994 time period. These findings are in agreement with both the burden and increase of the main anthropogenic Cl-bearing source gases at the surface during the 1980s, confirming that the stratospheric chlorine loading is primarily of anthropogenic origin.

  20. Factors Affecting the Hydrogen Environment Assisted Cracking Resistance of an AL-Zn-Mg-(Cu) Alloy

    SciTech Connect

    Young, G A; Scully, J R

    2002-04-09

    Precipitation hardenable Al-Zn-Mg alloys are susceptible to hydrogen environment assisted cracking (HEAC) when exposed to aqueous environments. In Al-Zn-Mg-Cu alloys, overaged tempers are used to increase HEAC resistance at the expense of strength but overaging has little benefit in low copper alloys. However, the mechanism or mechanisms by which overaging imparts HEAC resistance is poorly understood. The present research investigated hydrogen uptake, diffusion, and crack growth rate in 90% relative humidity (RH) air for both a commercial copper bearing Al-Zn-Mg-Cu alloy (AA 7050) and a low copper variant of this alloy in order to better understand the factors which affect HEAC resistance. Experimental methods used to evaluate hydrogen concentrations local to a surface and near a crack tip include nuclear reaction analysis (NRA), focused ion beam, secondary ion mass spectroscopy (FIB/SIMS) and thermal desorption spectroscopy (TDS). Results show that overaging the copper bearing alloys both inhibits hydrogen ingress from oxide covered surfaces and decreases the apparent hydrogen diffusion rates in the metal.

  1. 2H and 27Al Solid-State NMR Study of the Local Environments in Al-Doped 2-Line Ferrihydrite, Goethite, and Lepidocrocite

    PubMed Central

    2015-01-01

    Although substitution of aluminum into iron oxides and oxyhydroxides has been extensively studied, it is difficult to obtain accurate incorporation levels. Assessing the distribution of dopants within these materials has proven especially challenging because bulk analytical techniques cannot typically determine whether dopants are substituted directly into the bulk iron oxide or oxyhydroxide phase or if they form separate, minor phase impurities. These differences have important implications for the chemistry of these iron-containing materials, which are ubiquitous in the environment. In this work, 27Al and 2H NMR experiments are performed on series of Al-substituted goethite, lepidocrocite, and 2-line ferrihydrite in order to develop an NMR method to track Al substitution. The extent of Al substitution into the structural frameworks of each compound is quantified by comparing quantitative 27Al MAS NMR results with those from elemental analysis. Magnetic measurements are performed for the goethite series to compare with NMR measurements. Static 27Al spin–echo mapping experiments are used to probe the local environments around the Al substituents, providing clear evidence that they are incorporated into the bulk iron phases. Predictions of the 2H and 27Al NMR hyperfine contact shifts in Al-doped goethite and lepidocrocite, obtained from a combined first-principles and empirical magnetic scaling approach, give further insight into the distribution of the dopants within these phases. PMID:26321790

  2. Stress Corrosion Cracking in Al-Zn-Mg-Cu Aluminum Alloys in Saline Environments

    NASA Astrophysics Data System (ADS)

    Holroyd, N. J. Henry; Scamans, G. M.

    2013-03-01

    Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 °C to 80 °C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack ("pop-in" vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies ( E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 °C to 80 °C) for under-, peak-, and over-aged low-copper-containing alloys (<0.2 wt pct) are typically ranging from

  3. Corrosion behavior of TiN, TiAlN, TiAlSiN-coated 316L stainless steel in simulated proton exchange membrane fuel cell environment

    NASA Astrophysics Data System (ADS)

    Nam, Nguyen Dang; Vaka, Mahesh; Tran Hung, Nguyen

    2014-12-01

    To gain high hardness, good thermal stability and corrosion resistance, multicomponent TiAlSiN coating has been developed using different deposition methods. In this study, the influence of Al and Si on the electrochemical properties of TiN-coated 316L stainless steel as bipolar plate (BP) materials has been investigated in simulated proton exchange membrane fuel cell environment. The deposited TiN, TiAlN and TiAlSiN possess high hardness of 23.9, 31.7, 35.0 GPa, respectively. The coating performance of the TiN coating is enhanced by Al and Si addition due to lower corrosion current density and higher Rcoating and Rct values. This result could be attributed to the formation of crystalline-refined TiN(200), which improves the surface roughness, surface resistance, corrosion performance, and decreased passive current density.

  4. A Comparison of Ozone Measurements Made by the ATMOS, MAS, and SSBUV Instruments During ATLAS 1,2, and 3

    NASA Technical Reports Server (NTRS)

    Kriebel, D. L.; Bevilacqua, R. M.; Hilsenrath, E.; Gunson, M.; Hartmann, G. K.; Abrams, M.; Daehler, M.; Pauls, T. A.; Newchurch, M.; Aellig, C. P.; Bories, M. C.

    1996-01-01

    Ozone profile measurements were made by three instruments, ATMOS, MAS, and SSBUV, using distinctly different observing techniques, as part of the ATLAS Space Shuttle missions in March 1992, April 1993, and November 1994. ATMOS makes solar-occultation observations of infrared spectra using a Fourier transform interferometer. MAS uses a limb-scanning antenna to measure emission spectra at millimeter wavelengths. SSBUV is a nadir-viewing instrument measuring the transmission of scattered solar ultraviolet radiation modified by ozone absorption. A sample of zonal-mean mixing ratio profiles indicates that these three ATLAS instruments generally agree to within 10%, although a few potential biases have been noted. There are significant differences in the character of the agreement between ATLAS 1 and ATLAS 2 which will require further study.

  5. Factors Affecting the Hydrogen Environment Assisted Cracking Resistance of an Al-Zn-Mg-(Cu) Alloy

    SciTech Connect

    G.A. Young; J.R. Scully

    2001-09-12

    It is well established that Al-Zn-Mg-(Cu) aluminum alloys are susceptible to hydrogen environment assisted cracking (HEAC) when exposed to aqueous environments. In Al-Zn-Mg-Cu alloys, overaged tempers are commonly used to increase HEAC resistance at the expense of strength. Overaging has little benefit in low copper alloys. However, the mechanism or mechanisms by which overaging imparts HEAC resistance is poorly understood. The present research investigated hydrogen uptake, diffusion, and crack growth rate in 90% relative humidity (RH) air for both a commercial copper bearing Al-Zn-Mg-Cu alloy (AA 7050) and a low copper variant of this alloy in order to better understand the factors which affect HEAC resistance. Experimental methods used to evaluate hydrogen concentrations local to a surface and near a crack tip include nuclear reaction analysis (NRA), focused ion beam, secondary ion mass spectroscopy (FIB/SIMS) and thermal desorption spectroscopy (TDS). When freshly bared coupons of AA 7050 are exposed to 90 C, 90% RH air, hydrogen ingress follows inverse-logarithmic-type kinetics and is equivalent for underaged (HEAC susceptible) and overaged (HEAC resistant) tempers. However, when the native oxide is allowed to form (24 hrs in 25 C, 40% RH lab air) prior to exposure to 90 C, 90% RH air, underaged alloy shows significantly greater hydrogen ingress than the overaged alloy. Humid air is a very aggressive environment producing local ({approx}1{micro}m) hydrogen concentrations in excess of 10,000 wt. ppm at 90 C. In the copper bearing alloy, overaging also effects the apparent diffusivity of hydrogen. As AA 7050 is aged from underaged {yields} peak aged {yields} overaged, the activation energy for hydrogen diffusion increases and the apparent diffusivity for hydrogen decreases, In the low copper alloy, overaging has little effect on hydrogen diffusion. Comparison of the apparent activation energies for hydrogen diffusion and for K independent (stage II) crack growth

  6. Preliminary base heating environments for a generalized ALS LO2/LH2 launch vehicle, appendix 1 and 2

    NASA Technical Reports Server (NTRS)

    Bender, Robert L.; Reardon, John E.

    1989-01-01

    A secondary objective of contract NAS8-39141 is to provide base heating assessments, as required, to support Advanced Launch System (ALS) preliminary launch vehicle and propulsion system design studies. The ALS propulsion systems integration working group meeting (No. 3) recently completed in San Diego, California, focused attention on the need for base heating environment determination to provide preliminary requirements for LO2/LH2 propulsion systems currently being considered for ALS. We were requested to provide these environments for a range of possible propellant mixture and nozzle area ratios. Base heating environments can only be determined as a function of altitude when the engine operating conditions and vehicle base region geometry (engine arrangement) are known. If time dependent environments are needed to assess thermal loads, a trajectory must also be provided. These parameters are not fixed at this time since the ALS configurations and propulsion operating conditions are varied and continue to be studied by Phase B contractors. Therefore, for this study, a generalized LO2/LH2 system was selected along with a vehicle configuration consisting of a seven-engine booster and a three-engine core. MSFC provided guidance for the selection. We also selected a limited number of body points on the booster and core vehicles and engines for the environment estimates. Environments at these locations are representative of maximum heating conditions in the base region and are provided as a function of altitude only. Guidelines and assumptions for this assessment, methodology for determining the environments, and preliminary results are provided in this technical note. Refinements in the environments will be provided as the ALS design matures.

  7. MgAl2O4 spinel refractory as containment liner for high-temperature alkali salt containing environments

    DOEpatents

    Peascoe-Meisner, Roberta A [Knoxville, TN; Keiser, James R [Oak Ridge, TN; Hemric, James G [Knoxville, TN; Hubbard, Camden R [Oak Ridge, TN; Gorog, J Peter [Kent, WA; Gupta, Amul [Jamestown, NY

    2008-10-21

    A method includes containing a high-temperature alkali salt containing environment using a refractory containment liner containing MgAl.sub.2O.sub.4 spinel. A method, includes forming a refractory brick containing MgAl.sub.2O.sub.4 spinel having an exterior chill zone defined by substantially columnar crystallization and an interior zone defined by substantially equiaxed crystallization; and removing at least a portion of the exterior chill zone from the refractory brick containing MgAl.sub.2O.sub.4 spinel by scalping the refractory brick containing MgAl.sub.2O.sub.4 spinel to define at least one outer surface having an area of substantially equiaxed crystallization. A product of manufacture includes a refractory brick containing MgAl.sub.2O.sub.4 spinel including an interior zone defined by substantially equiaxed crystallization; and at least one outer surface having an area of substantially equiaxed crystallization.

  8. Uniform corrosion of FeCrAl alloys in LWR coolant environments

    NASA Astrophysics Data System (ADS)

    Terrani, K. A.; Pint, B. A.; Kim, Y.-J.; Unocic, K. A.; Yang, Y.; Silva, C. M.; Meyer, H. M.; Rebak, R. B.

    2016-10-01

    The corrosion behavior of commercial and model FeCrAl alloys and type 310 stainless steel was examined by autoclave tests and compared to Zircaloy-4, the reference cladding materials in light water reactors. The corrosion studies were carried out in three distinct water chemistry environments found in pressurized and boiling water reactor primary coolant loop conditions for up to one year. The structure and morphology of the oxides formed on the surface of these alloys was consistent with thermodynamic predictions. Spinel-type oxides were found to be present after hydrogen water chemistry exposures, while the oxygenated water tests resulted in the formation of very thin and protective hematite-type oxides. Unlike the alloys exposed to oxygenated water tests, the alloys tested in hydrogen water chemistry conditions experienced mass loss as a function of time. This mass loss was the result of net sum of mass gain due to parabolic oxidation and mass loss due to dissolution that also exhibits parabolic kinetics. The maximum thickness loss after one year of LWR water corrosion in the absence of irradiation was ∼2 μm, which is inconsequential for a ∼300-500 μm thick cladding.

  9. Effect of Environment on Fatigue Crack Wake Dislocation Structure in Al-Cu-Mg

    NASA Astrophysics Data System (ADS)

    Ro, Yunjo; Agnew, Sean R.; Gangloff, Richard P.

    2012-07-01

    Fatigue-induced dislocation structure was imaged at the crack surface using transmission electron microscopy (TEM) of focused ion beam (FIB)-prepared cross sections of naturally aged Al-4Cu-1.4Mg stressed at a constant stress intensity range (7 MPa√m) concurrent with either ultralow ( 10-8 Pa s) or high-purity (50 Pa s) water vapor exposure at 296 K (23 °C). A 200-to-600-nm-thick recovered-dislocation cell structure formed adjacent to the crack surface from planar slip bands in the plastic zone with the thickness of the cell structure and slip bands decreasing with increasing water vapor exposure. This result suggested lowered plastic strain accumulation in the moist environment relative to the vacuum. The previously reported fatigue crack surface crystallography is explained by the underlying dislocation substructure. For a vacuum, { { 1 1 1} } facets dominate the crack path from localized slip band cracking without resolvable dislocation cells, but cell formation causes some off- { { 1 1 1} } features. With water vapor present, the high level of hydrogen trapped within the developed dislocation structure could promote decohesion manifest as either low-index { { 100} } or { { 1 10} } facets, as well as high-index cracking through the fatigue-formed subgrain structure. These features and damage scenario provide a physical basis for modeling discontinuous environmental fatigue crack growth governed by both cyclic strain range and maximum tensile stress.

  10. Uniform corrosion of FeCrAl alloys in LWR coolant environments

    DOE PAGESBeta

    Terrani, K. A.; Pint, B. A.; Kim, Y. -J.; Unocic, K. A.; Yang, Y.; Silva, C. M.; Meyer, III, H. M.; Rebak, R. B.

    2016-06-29

    In this study, the corrosion behavior of commercial and model FeCrAl alloys and type 310 stainless steel was examined by autoclave tests and compared to Zircaloy-4, the reference cladding materials in light water reactors. The corrosion studies were carried out in three distinct water chemistry environments found in pressurized and boiling water reactor primary coolant loop conditions for up to one year. The structure and morphology of the oxides formed on the surface of these alloys was consistent with thermodynamic predictions. Spinel-type oxides were found to be present after hydrogen water chemistry exposures, while the oxygenated water tests resulted inmore » the formation of very thin and protective hematite-type oxides. Unlike the alloys exposed to oxygenated water tests, the alloys tested in hydrogen water chemistry conditions experienced mass loss as a function of time. This mass loss was the result of net sum of mass gain due to parabolic oxidation and mass loss due to dissolution that also exhibits parabolic kinetics. Finally, the maximum thickness loss after one year of LWR water corrosion in the absence of irradiation was ~2 μm, which is inconsequential for a ~300–500 μm thick cladding.« less

  11. Pressure Sounding of the Middle Atmosphere from ATMOS Solar Occultation Measurements of Atmospheric CO(sub 2) Absorption Lines

    NASA Technical Reports Server (NTRS)

    Abrams, M.; Gunson, M.; Lowes, L.; Rinsland, C.; Zander, R.

    1994-01-01

    A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(sub 2) lines with temperature-insensitive intensities. Tangent pressures are determined with a spectroscopic precision of 1-3%, corresponding to a tangent point height precision, depending on the scale height, of 70-210 meters.

  12. Life expectancy of modular Ti6Al4V hip implants: influence of stress and environment.

    PubMed

    Chandra, A; Ryu, J J; Karra, P; Shrotriya, P; Tvergaard, V; Gaisser, M; Weik, T

    2011-11-01

    Stress dependent electrochemical dissolution is identified as one of the key mechanisms governing surface degradation in fretting and crevice corrosion of biomedical implants. The present study focuses on delineating the roles of mechanical stress and chemical conditions on the life expectancy of modular hip implants. First, material removal on a stressed surface of Ti6Al4V subjected to single asperity contact is investigated experimentally to identify the influence of contact load, in-plane stress and chemical environment on mean wear rates. A range of known stress levels are applied to the specimen while its surface is mechanically stimulated in different non-reactive to oxidizing aqueous environments. Evolution of surface degradation is monitored, and its mechanism is elucidated. This phase allows estimation of Preston Constant which is later used in the analysis. Second phase of the work is semi-analytical and computational, where, based on the estimated Preston constant and other material and process parameters, the scratch propensity (consisting of magnitude of scratch depth and their frequency per unit area) due to micro-motion in modular hip implants is estimated. The third phase views these scratches as initial notches and utilizes a mixed-mode fatigue crack propagation model to estimate the critical crack length for onset of instability. The number of loading cycles needed to reach this critical crack length is then labeled as the expected life of the implant under given mechanical and chemical conditions. Implications of different material and process conditions to life expectancy of orthopedic implants are discussed. It is observed that transverse micro-motion, compared to longitudinal micro-motion, plays a far more critical role in determining the implant life. Patient body weight, as well as proximity of the joint fluid to its iso-electric point play key roles in determining wear rates and associated life expectancies of modular hip implants

  13. Influence of testing environment on the room temperature ductility of FeAl alloys

    NASA Technical Reports Server (NTRS)

    Gaydosh, D. J.; Nathal, M. V.

    1990-01-01

    The effects of testing atmospheres (air, O2, N2, and vacuum) on the room-temperature ductility of Fe-40Al, Fe-40Al-0.5B, and Fe-50Al alloys were investigated. The results confirmed the decrease in room-temperature ductility of Fe-rich FeAl alloys by the interaction of the aluminide with water vapor, reported previously by Liu et al. (1989). The highest ductilities were measured in the atmosphere with the lowest moisture levels, i.e., in vacuum. It was found that significant ductility is still restricted to Fe-rich alloys (Fe-40Al), as the Fe-50Al alloy remained brittle under all testing conditions. It was also found that slow cooling after annealing was beneficial, and the effect was additive to the environmental effect. The highest ductility measurements in this study were 9 percent elongation in furnace-cooled Fe-40Al and in Fe-40Al-0.5B, when tested in vacuum.

  14. The epidemiology of ALS: a conspiracy of genes, environment and time.

    PubMed

    Al-Chalabi, Ammar; Hardiman, Orla

    2013-11-01

    Amyotrophic lateral sclerosis (ALS) is a relentlessly progressive neurodegenerative disease of motor neurons, resulting in worsening weakness of voluntary muscles until death from respiratory failure occurs after about 3 years. Although great advances have been made in our understanding of the genetic causes of ALS, the contribution of environmental factors has been more difficult to assess. Large-scale studies of the clinical patterns of ALS, individual histories preceding the onset of ALS, and the rates of ALS in different populations and groups have led to improved patient care, but have not yet revealed a replicable, definitive environmental risk factor. In this Review, we outline what is currently known of the environmental and genetic epidemiology of ALS, describe the current state of the art with respect to the different types of ALS, and explore whether ALS should be considered a single disease or a syndrome. We examine the relationship between genetic and environmental risk factors, and propose a disease model in which ALS is considered to be the result of environmental risks and time acting on a pre-existing genetic load, followed by an automatic, self-perpetuating decline to death. PMID:24126629

  15. High Excitation Rydberg Levels of Fe I from the ATMOS Solar Spectrum at 2.5 and 7 microns

    NASA Technical Reports Server (NTRS)

    Schoenfeld, W. G.; Chang, E. S.; Geller, M.; Johansson, S.; Nave, G.; Sauval, A. J.; Grevesse, N.

    1995-01-01

    The quadrupole-polarization theory has been applied to the 3d(sup 6)4S(D-6)4f and 5g subconfigurations of Fe I by a parametric fit, and the fitted parameters are used to predict levels in the 6g and 6h subconfigurations. Using the predicted values, we have computed the 4f-6g and 5g-6h transition arrays and made identifications in the ATMOS infrared solar spectrum. The newly identified 6g and 6h levels, based on ATMOS wavenumbers, are combined with the 5g levels and found to agree with the theoretical values with a root mean-squared-deviation of 0.042/ cm. Our approach yields a polarizability of 28.07 a(sub o, sup 2) and a quadrupole moment of 0.4360 +/- 0.0010 ea(sup 2, sub o) for Fe II, as well as an improved ionization potential of 63737.700 +/- 0.010/ cm for Fe I.

  16. ATMOS/ATLAS-3 Observations of Long-Lived Tracers and Descent in the Antarctic Vortex in November 1994

    NASA Technical Reports Server (NTRS)

    Abrams, M. C.; Manney, G. L.; Gunson, M. R.; Abbas, M. M.; Chang, A. Y.; Goldman, A.; Irion, F. W.; Michelsen, H. A.; Newchurch, M. J.; Rinsland, C. P.; Salawitch, R. J.; Stiller, G. P.; Zander, R.

    1996-01-01

    Observations of the long-lived tracers N2O, CH4 and HF obtained by the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument in early November 1994 are used to estimate average descent rates during winter in the Antarctic polar vortex of 0.5 to 1.5 km/month in the lower stratosphere, and 2.5 to 3.5 km/month in the middle and upper stratosphere. Descent rates inferred from ATMOS tracer observations agree well with theoretical estimates obtained using radiative heating calculations. Air of mesospheric origin (N2O less than 5 ppbV) was observed at altitudes above about 25 km within the vortex. Strong horizontal gradients of tracer mixing ratios, the presence of mesospheric air in the vortex in early spring, and the variation with altitude of inferred descent rates indicate that the Antarctic vortex is highly isolated from midlatitudes throughout the winter from approximately 20 km to the stratopause. The 1994 Antarctic vortex remained well isolated between 20 and 30 km through at least mid-November.

  17. ATMOS/ATLAS 1 measurements of sulfur hexafluoride (SF6) in the lower stratosphere and upper troposphere

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Abrams, M. C.; Lowes, L. L.; Zander, R.; Mahieu, E.

    1993-01-01

    Vertical profiles of sulfur hexafluoride (SF6) in the lower stratosphere and upper troposphere have been retrieved from 0.01/cm resolution infrared solar occultation spectra recorded by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the ATLAS (Atmospheric Laboratory for Applications and Science) 1 shuttle mission of March 24 to April 2, 1992. Based on measurements of the unresolved absorption by the SF6 mu(sub 3) band Q branch at 947.9/cm, average SF6 volume mixing ratios and 1-sigma uncertainties of 3.20 +/- 0.54 parts per trillion by volume (pptv; 10(exp -12) ppv) at 200 mbar (approximately 11.8 km) declining to 2.86 +/- 0.29 pptv at 100 mbar (approximately 16.2 km) and 1.95 +/- 0.50 pptv at 30 mbar (approximately 23.9 km) have been retrieved. The profiles show no obvious dependence with latitude over the range of the measurements (eight occultations spanning 28 deg S to 54 deg S). Assuming an exponential growth model and applying a correction for the interhemispheric concentration difference, an average SF6 rate of increase of 8.7 +/- 2.2% per year, 2 sigma, between 12 and 18 km has been derived by fitting the present measurements, ATMOS measurements from the April-May 1985 Spacelab 3 mission, and balloon-borne IR measurements obtained in March 1981 and June 1988.

  18. Corrosion behavior of an HVOF-sprayed Fe3Al coating in a high-temperature oxidizing/sulfidizing environment

    SciTech Connect

    Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Holcomb, Gordon R.; Ziomek-Moroz, Margaret; Shrestha, S.; Harvey, D.

    2005-01-01

    An iron aluminide (Fe3Al) intermetallic coating was deposited onto a F22 (2.25Cr-1Mo) steel substrate using a JP-5000 high velocity oxy-fuel (HVOF) thermal spray system. The as-sprayed coating was examined by electron microscopy and X-ray diffraction and was characterized in terms of oxidation and adhesion. Fe3Al-coated steel specimens were exposed to a mixed oxidizing/sulfidizing environment at 500, 600, 700, and 800DGC for approximately seven days. The gaseous environment consisted of N2-10%CO-5%CO2-2%H2O-0.12%H2S (by volume). All specimens gained mass after exposure to the environment and the mass gains were found to be inversely proportional to temperature increases. Representative specimens exposed at each temperature were cross-sectioned and subjected to examination under a scanning electron microscope (SEM) and X-ray mapping. Results are presented in terms of corrosion weight gain and corrosion product formation. The purpose of the research presented here was to evaluate the effectiveness of an HVOF-sprayed Fe3Al coating in protecting a steel substrate exposed to a fossil energy environment.

  19. Crystallization of LiAlSiO4 Glass in Hydrothermal Environments at Gigapascal Pressures-Dense Hydrous Aluminosilicates.

    PubMed

    Spektor, Kristina; Fischer, Andreas; Häussermann, Ulrich

    2016-08-15

    High-pressure hydrothermal environments can drastically reduce the kinetic constraints of phase transitions and afford high-pressure modifications of oxides at comparatively low temperatures. Under certain circumstances such environments allow access to kinetically favored phases, including hydrous ones with water incorporated as hydroxyl. We studied the crystallization of glass in the presence of a large excess of water in the pressure range of 0.25-10 GPa and at temperatures from 200 to 600 °C. The p and T quenched samples were analyzed by powder X-ray diffraction, scanning electron microscopy, and IR spectroscopy. At pressures of 0.25-2 GPa metastable zeolite Li-ABW and stable α-eucryptite are obtained at low and high temperatures, respectively, with crystal structures based on tetrahedrally coordinated Al and Si atoms. At 5 GPa a new, hydrous phase of LiAlSiO4, LiAlSiO3(OH)2 = LiAlSiO4·H2O, is produced. Its crystal structure was characterized from single-crystal X-ray diffraction data (space group P21/c, a = 9.547(3) Å, b = 14.461(5) Å, c = 5.062(2) Å, β = 104.36(1)°). The monoclinic structure resembles that of α-spodumene (LiAlSi2O6) and constitutes alternating layers of chains of corner-condensed SiO4 tetrahedra and chains of edge-sharing AlO6 octahedra. OH groups are part of the octahedral Al coordination and extend into channels provided within the SiO4 tetrahedron chain layers. At 10 GPa another hydrous phase of LiAlSiO4 with presently unknown structure is produced. The formation of hydrous forms of LiAlSiO4 shows the potential of hydrothermal environments at gigapascal pressures for creating truly new materials. In this particular case it indicates the possibility of generally accessing pyroxene-type aluminosilicates with crystallographic amounts of hydroxyl incorporated. This could also have implications to geosciences by representing a mechanism of water storage and transport in the depths of the Earth. PMID:27482770

  20. Alloy development of FeAl aluminide alloys for structural use in corrosive environments

    SciTech Connect

    Liu, C.T.; Sikka, V.K.; McKamey, C.G.

    1993-02-01

    Objectives include adequate ductilities ([ge]10%) at ambient temperature, high-temperature strength better than stainless steels (types 304 and 316), and fabricability and weldability by conventional techniques (gas tungsten arc). The alloys should be capable of being corrosion resistant in molten nitrate salts with rates lower than other iron-base structural alloys and coating materials (such as Fe-Cr-Al alloys). Such corrosion rates should be less than 0.3 mm per year. The FeAl aluminide containing 35.8 at. % Al was selected as base composition. Preliminary studies indicate that additions of B and Zr, increase the room-temperature ductility of FeAl. Further alloying with 0.2% Mo, and/or 5% Cr, improves the creep. Our preliminary alloying effort has led to identification of the following aluminide composition with promising properties: Fe - (35 [plus minus] 2)Al - (0.3 [plus minus] 0.2)Mo - (0.2 [plus minus] 0.15)Zr - (0.3 [plus minus] 0.2)B- up to 5Cr, at. %. However, this composition is likely to be modified in future work to improve the weldability of the alloy. The FeAl alloy FA-362 (Fe-35.8% Al-0.2% Mo-0.05% Zr-0.24% B) produced by hot extrusion at 900C showed a tensile ductility of more than 10% at room temperature and a creep rupture life longer than unalloyed FeAl by more than an order of magnitude at 593C at 138 MPa. Melting and processing of scaled-up heats of selected FeAl alloys are described. Forging, extruding, and hot-rolling processes for the scale-up heats are also described.

  1. Alloy development of FeAl aluminide alloys for structural use in corrosive environments

    SciTech Connect

    Liu, C.T.; Sikka, V.K.; McKamey, C.G.

    1993-02-01

    Objectives include adequate ductilities ({ge}10%) at ambient temperature, high-temperature strength better than stainless steels (types 304 and 316), and fabricability and weldability by conventional techniques (gas tungsten arc). The alloys should be capable of being corrosion resistant in molten nitrate salts with rates lower than other iron-base structural alloys and coating materials (such as Fe-Cr-Al alloys). Such corrosion rates should be less than 0.3 mm per year. The FeAl aluminide containing 35.8 at. % Al was selected as base composition. Preliminary studies indicate that additions of B and Zr, increase the room-temperature ductility of FeAl. Further alloying with 0.2% Mo, and/or 5% Cr, improves the creep. Our preliminary alloying effort has led to identification of the following aluminide composition with promising properties: Fe - (35 {plus_minus} 2)Al - (0.3 {plus_minus} 0.2)Mo - (0.2 {plus_minus} 0.15)Zr - (0.3 {plus_minus} 0.2)B- up to 5Cr, at. %. However, this composition is likely to be modified in future work to improve the weldability of the alloy. The FeAl alloy FA-362 (Fe-35.8% Al-0.2% Mo-0.05% Zr-0.24% B) produced by hot extrusion at 900C showed a tensile ductility of more than 10% at room temperature and a creep rupture life longer than unalloyed FeAl by more than an order of magnitude at 593C at 138 MPa. Melting and processing of scaled-up heats of selected FeAl alloys are described. Forging, extruding, and hot-rolling processes for the scale-up heats are also described.

  2. Concentrations of carbonyl sulfide and hydrogen cyanide in the free upper troposphere and lower stratosphere deduced from ATMOS/Spacelab 3 infrared solar occultation spectra

    NASA Technical Reports Server (NTRS)

    Zander, R.; Rinsland, C. P.; Russell, J. M., III; Farmer, C. B.; Norton, R. H.

    1988-01-01

    This paper presents the results on the volume mixing ratio profiles of carbonyl sulfide and hydrogen cyanide, deduced from the spectroscopic analysis of IR solar absorption spectra obtained in the occultation mode with the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument during its mission aboard Spacelab 3. A comparison of the ATMOS measurements for both northern and southern latitudes with previous field investigations at low midlatitudes shows a relatively good agreement. Southern Hemisphere volume mixing ratio profiles for both molecules were obtained for the first time, as were the profiles for the Northern Hemisphere covering the upper troposphere and the lower stratosphere simultaneously.

  3. Droplet Growth Kinetics in Various Environments

    NASA Astrophysics Data System (ADS)

    Raatikainen, T. E.; Lathem, T. L.; Moore, R.; Lin, J. J.; Cerully, K. M.; Padro, L.; Lance, S.; Cozic, J.; Anderson, B. E.; Nenes, A.

    2012-12-01

    The largest uncertainties in the effects of atmospherics aerosols on the global radiation budget are related to their indirect effects on cloud properties (IPCC, the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007). Cloud formation is a kinetic process where the resulting cloud properties depend on aerosol properties and meteorological parameters such as updraft velocity (e.g. McFiggans et al., Atmos. Chem. Phys., 6, 2593-2649, 2006). Droplet growth rates are limited by the water vapor diffusion, but additional kinetic limitations, e.g., due to organic surface films, slow solute dissociation or highly viscous or glassy aerosol states have been hypothesized. Significant additional kinetic limitations can lead to increased cloud droplet number concentration, thus the effect is similar to those of increased aerosol number concentration or changes in vertical velocity (e.g. Nenes et al., Geophys. Res. Lett., 29, 1848, 2002). There are a few studies where slow droplet growth has been observed (e.g. Ruehl et al., Geophys. Res. Lett., 36, L15814, 2009), however, little is currently known about their global occurrence and magnitude. Cloud micro-physics models often describe kinetic limitations by an effective water vapor uptake coefficient or similar parameter. Typically, determining aerosol water vapor uptake coefficients requires experimental observations of droplet growth which are interpreted by a numerical droplet growth model where the uptake coefficient is an adjustable parameter (e.g. Kolb et al., Atmos. Chem. Phys., 10, 10561-10605, 2010). Such methods have not been practical for high time-resolution or long term field measurements, until a model was recently developed for analyzing Droplet Measurement Technologies (DMT) cloud condensation nuclei (CCN) counter data (Raatikainen et al., Atmos. Chem. Phys., 12, 4227-4243, 2012). Model verification experiments showed that the calibration aerosol droplet size can be predicted accurately

  4. Investigation of the possible association of 10Be and 26Al with biogenic matter in the marine environment

    NASA Astrophysics Data System (ADS)

    Bourles, D.; Raisbeck, G. M.; Yiou, F.; Loiseaux, J. M.; Lieuvin, M.; Klein, J.; Middleton, R.

    1984-11-01

    As part of a more general investigation of the mechanism by which 10Be and 26Al are transported in the ocean, and eventually incorporated in various marine reservoirs, and the extent to which they are homogenized with 9Be and 27Al, we are studying the possible association of these isotopes with biogenic matter in the marine environment. To this end we have made measurements of 10Be and 9Be in: (a) the carbonate fraction of several marine animals (clam, cockel, starfish, mussel) and the organic fraction of mussels; (b) 20 samples of a 460 m coral reef core extending from the present to ˜ 7 Ma ago; (c) 2 samples of marine plankton; (d) 1 sample of paniculate matter in ocean surface water. 26Al has been measured in two coral samples. 10Be measurements have been made on the Grenoble cyclotron, the University of Pennsylvania tandem and, most recently, on the French Tandetron. 26Al was measured at the Pennsylvania tandem. 9Be and 27Al were measured using flameless atomic absorption spectrometry. These investigations have taken on added significance with the discovery of 10Be in crude petroleum, and the possibility that 14Be concentration (or 10Be/ 9Be ratios) might be used to estimate the age of recent petroleum, or petroleum precursor, formation.

  5. First flight of the ATMOS instrument during the Spacelab 3 Mission, April 29 through May 6, 1985

    NASA Technical Reports Server (NTRS)

    Farmer, Crofton B.; Raper, Odell F.; Ocallaghan, Fred G.

    1987-01-01

    The underlying rationale and the implementation of the Atmospheric Trace Molecule Spectroscopy (ATMOS) investigation are discussed, a description of the sensor is given, and the ground tests and integration procedures leading to the Spacelab 3 flight are described. The data reduction and analysis procedures used after the flight are discussed, a number of examples of the spectra obtained are shown, and the concentration profiles as a function of altitude for the minor and trace gases measured during the mission are presented. On the basis of the instrument's ability to survive both the launch and the reentry of the shuttle and its flawless performance while on orbit, the concepts involved in the investigation have been proved by the Spacelab 3 flight, and an extended series of reflights is currently being planned as a part of the Atmospheric Laboratory for Applications and Science (ATLAS) Missions. The goals for the investigation during these missions are also discussed.

  6. High missing OH reactivity in summertime boreal forest environment

    NASA Astrophysics Data System (ADS)

    Nölscher, A. C.; Williams, J.; Sinha, V.; Song, W.; Johnson, A.; Yassaa, N.; Phillips, G.; Crowley, J.; Axinte, R.; Fischer, H.; Gonzales, D.; Valverde-Canossa, J.; Vogel, A.; Hoffmann, T.; Rantala, P.; Rinne, J.; Kulmala, M.; Ouwersloot, H.; Vila, J.; Lelieveld, J.

    2012-04-01

    Forest emissions represent a strong potential sink for the main tropospheric oxidant, the hydroxyl radical (OH). Resulting photochemical products can influence ambient ozone, contribute to particle formation and growth processes, and therefore impact climate and air quality. Direct measurements of total OH reactivity in ambient air can reveal gaps in the general understanding of reactive gaseous emissions from the biosphere to the atmosphere. By comparing the contribution from individually measured compounds to the overall OH sink and the directly measured total OH reactivity, the size of any unaccounted for, or "missing" sink can be deduced. In July and August 2010 an intensive field measurement campaign (HUMPPA-COPEC 2010) was performed at the Finnish boreal forest station SMEAR II in Hyytiälä (Latitude 61° 51' N; Longitude 24° 17' E) to investigate the summertime emissions and photochemistry of volatile organic compounds (VOCs) [1]. Speciated VOCs, the key oxidants OH, O3 and NO3, as well as aerosol, ions and other trace gases were quantified. Total OH reactivity was measured directly using the Comparative Reactivity Method (CRM) [2]. This total OH reactivity method is an in-situ determination of the total loss rate of OH radicals caused by all reactive species in ambient air. During HUMPPA-COPEC 2010, total OH reactivity was monitored both inside and directly above the canopy. The impact of various parameters such as temperature and light dependent biogenic emissions and reaction products in "normal" and "stressed" conditions, the long-range transport of pollution and the boundary layer height development were characterized. For "normal" boreal conditions a missing reactivity of 58% was determined, whereas for "stressed" boreal conditions this increased to 89 %. Possible explanations are proposed to explain the high missing OH reactivity in summertime boreal forest environment. [1] J. Williams et al, 2011, Atmos. Chem. Phys., 11, 10599-10618 [2] V. Sinha et

  7. Synthesis of DNL-6 with a high concentration of Si (4 Al) environments and its application in CO(2) separation.

    PubMed

    Su, Xiong; Tian, Peng; Fan, Dong; Xia, Qinghua; Yang, Yue; Xu, Shutao; Zhang, Lin; Zhang, Ying; Wang, Dehua; Liu, Zhongmin

    2013-05-01

    The synthesis of DNL-6 with a high concentration of Si (4 Al) environments [Si/(Si+Al+P)=0.182 mol, denoted as M-DNL-6] is demonstrated. This represents the highest reported concentration of such environments in silicoaluminophosphate (SAPO) molecular sieves. Adsorption studies show that the high Si (4 Al) content in M-DNL-6, with an increased number of Brønsted acid sites in the framework, greatly promotes the adsorption of CO(2). M-DNL-6 exhibits a large CO(2) uptake capacity of up to 6.18 mmol g(-1) at 273 K and 101 kPa, and demonstrates high ratios of CO(2)/CH(4) and CO(2)/N(2) separation. From breakthrough and cycling experiments, M-DNL-6 demonstrates the ability to completely separate CO(2) from CH(4) or N(2) with a dynamic capacity of approximately 8.0 wt % before breakthrough. Importantly, the adsorbed CO(2) is easily released from the adsorbent through a simple gas purging operation at room temperature to regain 95 % of the original adsorption capacity. These results suggest that M-DNL-6 can be used as a potential adsorbent for CO(2) capture in pressure swing adsorption processes. PMID:23606439

  8. Synthetic high-resolution near-IR spectra of the Sun for planetary data reductions made from ATMOS/Spacelab-3 and Atlas-3 data

    NASA Astrophysics Data System (ADS)

    Seo, Haingja; Kim, Sang J.; Hwang, Sungwon; Jung, Aeran; Kim, Ji Hyun; Kim, Joo Hyeon; Kim, Kap-Sung; Lee, Jinny; Jang, Minhwan

    2007-12-01

    We have constructed synthetic solar spectra for the 2302-4800 cm -1 (2.08-4.34 μm) range, a spectral range where planetary objects mainly emit reflected sunlight, using ATMOS (Atmospheric Trace Molecule Spectroscopy)/Spacelab-3 and Atlas-3 spectra, of which resolution is 0.01 cm -1. We adopted Voigt line profiles for the modeling of line shapes based on an atlas of line identifications compiled by Geller [Geller, M., 1992. Key to Identification of Solar Features. A High-Resolution Atlas of the Infrared Spectrum of the Sun and the Earth Atmosphere from Space. NASA Reference Publ. 1224, vol. III. NASA, Washington, DC, pp. 1-22], who derived solar line positions and intensities from contaminated high-resolution solar spectra obtained by ATMOS/Spacelab-3. Because the ATMOS spectra in these wavelength ranges are compromised by absorption lines of molecules existing in Earth's high-altitude atmosphere and in the compartment of the spacecraft, the direct use of these high-resolution solar spectra has been inconvenient for the data reductions of planetary spectra. We compared the synthetic solar spectra with the ATMOS spectra, and obtained satisfactory fits for the majority of the solar lines with the exception of abnormal lines, which do not fit with Voigt line profiles. From the model fits, we were able to determine Voigt line parameters for the majority of solar lines; and we made a list of the abnormal lines. We also constructed telluric-line-free solar spectra by manually eliminating telluric lines from the ATMOS spectra and filling the gaps with adjacent continua. These synthetic solar spectra will be useful to eliminate solar continua from spectra of planetary objects to extract their own intrinsic spectral features.

  9. New particle formation events as a source for cloud condensation nuclei in an urban environment

    NASA Astrophysics Data System (ADS)

    Wonaschütz, Anna; Burkart, Julia; Wagner, Robert; Reischl, Georg; Steiner, Gerhard; Hitzenberger, Regina

    2014-05-01

    Nucleation and growth events have been observed in many remote, urban and rural environments. The new particles can contribute significantly to cloud condensation nuclei concentrations, after growing into the appropriate size range (Kerminen et al., 2012). Several studies have attempted to quantify this contribution (e.g. Asmi et al., 2011, Matsui et al., 2013), but only a limited number of them to date have used simultaneous measurements of CCN concentrations and particle size distributions for this purpose (e.g. Levin et al., 2012). In this study, a data set from an urban background station, consisting of 22 months of size distribution and 12 months of CCN concentration measurements (Burkart et al., 2011, Burkart et al., 2012) with 10 months of overlapping measurements is combined to explore the variability of CCN concentrations, their possible causes, and the contribution of nucleation and growth events to CCN concentrations. Consistent with observations in many other locations, nucleation and growth events occur on 30% of all days in spring and summer, on 11% of days in fall and on 4% of days in winter. This suggests a potentially large source of CCN from nucleation and growth events, particularly in the warm season. We acknowledge funding from FWF (Austrian Science Fund) P19515-N20 References: Asmi E., Kivekas, N., Kerminen, V. M., Komppula, M., Hyvarinen, A. P., Hatakka, J., Viisanen, Y., and Lihavainen, H.: Secondary new particle formation in Northern Finland Pallas site between the years 2000 and 2010, Atmos. Chem. Phys., 11, 12959-12972, doi: 10.5194/acp-11-12959-2011, 2011 Burkart J., Steiner, G., Reischl, G., and Hitzenberger, R.: Long-term study of cloud condensation nuclei (CCN) acticvation of the atmospheric aerosol in Vienna, Atmos. Environ., 45, 5751-5759, doi: 10.1016/j.atmosenv.2011.07.022, 2011. Burkart J., Hitzenberger, R., Reischl, G., Bauer, H., Leder, K., and Puxbaum, H.: Activation of "synthetic ambient" aerosols - relation to chemical

  10. Thermal Behavior of Fe2O3/Al Thermite Mixtures in Air and Vacuum Environments

    SciTech Connect

    Duraes, L.; Santos, R.; Correia, A.; Campos, J.; Portugal, A.

    2006-07-28

    In this work, the thermal behavior of Fe2O3/Al thermite mixtures, in air and vacuum, is studied. The individual reactants and three mixtures - stoichiometric and over aluminized - are tested, by Simultaneous Thermal Analysis (STA) and heating microscopy, with a heating rate of 10 deg. C/min. The STA results show that the presence of O2 from air, or from residual air in vacuum, influenced the reaction scheme. The Al oxidation by this oxygen was extensive, making the thermite reaction with Fe2O3 unviable. There was also evidence of significant conversion of the Fe2O3 into Fe3O4, supporting the previous conclusion. So, the STA curves for the three mixtures were similar and displayed features of the individual reactants' curves. The heating microscopy images confirmed the STA conclusions, with one exception: the thermal explosion of the Al sample close to 550 deg. C. The absence of this phenomenon in STA results was explained by the limited amount of material used in each sample.

  11. Phase progression of γ-Al2O3 nanoparticles synthesized in a solvent-deficient environment.

    PubMed

    Smith, Stacey J; Amin, Samrat; Woodfield, Brian F; Boerio-Goates, Juliana; Campbell, Branton J

    2013-04-15

    Our simple and uniquely cost-effective solvent-deficient synthetic method produces 3-5 nm Al2O3 nanoparticles which show promise as improved industrial catalyst-supports. While catalytic applications are sensitive to the details of the atomic structure, a diffraction analysis of alumina nanoparticles is challenging because of extreme size/microstrain-related peak broadening and the similarity of the diffraction patterns of various transitional Al2O3 phases. Here, we employ a combination of X-ray pair-distribution function (PDF) and Rietveld methods, together with solid-state NMR and thermogravimetry/differential thermal analysis-mass spectrometry (TG/DTA-MS), to characterize the alumina phase-progression in our nanoparticles as a function of calcination temperature between 300 and 1200 °C. In the solvent-deficient synthetic environment, a boehmite precursor phase forms which transitions to γ-Al2O3 at an extraordinarily low temperature (below 300 °C), but this γ-Al2O3 is initially riddled with boehmite-like stacking-fault defects that steadily disappear during calcination in the range from 300 to 950 °C. The healing of these defects accounts for many of the most interesting and widely reported properties of the γ-phase. PMID:23557087

  12. Probing the local environment of substitutional Al^{3+} in goethite using X-ray absorption spectroscopy and first-principles calculations

    NASA Astrophysics Data System (ADS)

    Ducher, Manoj; Blanchard, Marc; Vantelon, Delphine; Nemausat, Ruidy; Cabaret, Delphine

    2016-03-01

    We present experimental and calculated Al K-edge X-ray absorption near-edge structure (XANES) spectra of aluminous goethite with 10-33 mol% of AlOOH and diaspore. Significant changes are observed experimentally in the near- and pre-edge regions with increasing Al concentration in goethite. First-principles calculations based on density functional theory (DFT) reproduce successfully the experimental trends. This permits to identify the electronic and structural parameters controlling the spectral features and to improve our knowledge of the local environment of {Al}^{3+} in the goethite-diaspore partial solid solution. In the near-edge region, the larger peak spacing in diaspore compared to Al-bearing goethite is related to the nature (Fe or Al) of the first cation neighbours around the absorbing Al atom (Al*). The intensity ratio of the two near-edge peaks, which decreases with Al concentration, is correlated with the average distance of the first cations around Al* and the distortion of the {AlO}_6 octahedron. Finally, the decrease in intensity of the pre-edge features with increasing Al concentration is due to the smaller number of Fe atoms in the local environment of Al since Al atoms tend to cluster. In addition, it is found that the pre-edge features of the Al K-edge XANES spectra enable to probe indirectly empty 3 d states of Fe. Energetic, structural and spectroscopic results suggest that for Al concentrations around 10 mol%, Al atoms can be considered as isolated, whereas above 25 mol%, Al clusters are more likely to occur.

  13. High temperature oxidation of HFPD thermal-sprayed MCrAlY coatings in simulated gas turbine environments

    NASA Astrophysics Data System (ADS)

    Belzunce, F. J.; Higuera, V.; Poveda, S.; Carriles, A.

    2002-12-01

    NiCrAlY and CoNiCrAlY powders were thermal-sprayed using the high frequency pulse detonation method (HFPD) onto AISI 310 austenitic stainless steel samples to obtain dense, adherent, high temperature oxidation resistant coatings. The oxidation behavior of both types of coatings in a 1000°C simulated gas turbine environment was experimentally determined. The porosity, hardness, coating thickness, and microstructure were not significantly modified by the high temperature oxidation cycles, but the internal oxidation increases significantly after a very low oxidation time. Surface phase composition was evaluated using x-ray diffraction (XRD) and scanning electron microscope (SEM) techniques, revealing the formation of a continuous and highly protective alumina layer. The oxidation kinetics of both coatings can be characterized by parabolic rate constants, which are very close to those for the formation of aluminum oxide on nickel or cobalt based alloys at similar conditions.

  14. Cold Spraying of Cu-Al-Bronze for Cavitation Protection in Marine Environments

    NASA Astrophysics Data System (ADS)

    Krebs, S.; Gärtner, F.; Klassen, T.

    2015-01-01

    Traveling at high speeds, ships have to face the problem of rudder cavitation-erosion. At present, the problem is countered by fluid dynamically optimized rudders, synthetic, and weld-cladded coatings on steel basis. Nevertheless, docking and repair is required after certain intervals. Bulk Cu-Al-bronzes are in use at ships propellers to withstand corrosion and cavitation. Deposited as coatings with bulk-like properties, such bronzes could also enhance rudder life times. The present study investigates the coating formation by cold spraying CuAl10Fe5Ni5 bronze powders. By calculations of the impact conditions, the range of optimum spray parameters was preselected in terms of the coating quality parameter η on steel substrates with different temperatures. As-atomized and annealed powders were compared to optimize cavitation resistance of the coatings. Results provide insights about the interplay between the mechanical properties of powder and substrate for coating formation. Single particle impact morphologies visualize the deformation behavior. Coating performance was assessed by analyzing microstructures, bond strength, and cavitation resistance. These first results demonstrate that cold-sprayed bronze coatings have a high potential for ensuring a good performances in rudder protection. With further optimization, such coatings could evolve towards a competitive alternative to existing anti-cavitation procedures.

  15. Corrosion Resistance of Fe-Al/Al2O3 Duplex Coating on Pipeline Steel X80 in Simulated Oil and Gas Well Environment

    NASA Astrophysics Data System (ADS)

    Huang, Min; Wang, Yu; Wang, Ping-Gu; Shi, Qin-Yi; Zhang, Meng-Xian

    2015-04-01

    Corrosion resistant Fe-Al/Al2O3 duplex coating for pipeline steel X80 was prepared by a combined treatment of low-temperature aluminizing and micro-arc oxidation (MAO). Phase composition and microstructure of mono-layer Fe-Al coating and Fe-Al/Al2O3 duplex coating were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) with energy dispersive spectrometer (EDS). Corrosion resistance of the coated pipeline steel X80 in a simulated oil and gas well condition was also investigated. Mono-layer Fe-Al coating consists of Fe2Al5 and FeAl, which is a suitable transitional layer for the preparation of ceramic coating by MAO on the surface of pipeline steel X80. Under the same corrosion condition at 373 K for 168 h with 1 MPa CO2 and 0.1 MPa H2S, corrosion weight loss rate of pipeline steel X80 with Fe-Al/Al2O3 duplex coating decreased to 23% of original pipeline steel X80, which improved by 10% than that of pipeline steel X80 with mono-layer Fe-Al coating. It cannot find obvious cracks and pits on the corrosion surface of pipeline steel X80 with Fe-Al/Al2O3 duplex coating.

  16. Pressure sounding of the middle atmosphere from ATMOS solar occultation measurements of atmospheric CO(2) absorption lines.

    PubMed

    Abrams, M C; Gunson, M R; Lowes, L L; Rinsland, C P; Zander, R

    1996-06-01

    A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier-transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(2) lines with temperature-insensitive strengths by measuring the slant-column CO(2) amount and by adjusting the viewing geometry until the calculated column matches the observed column. Tangent pressures are determined with a spectroscopic precision of l%-3%, corresponding to a tangent-point height precision of 70-210 m. The total uncertainty is limited primarily by the quality of the spectra and ranges between 4% and 6% (280-420 m) for spectra with signal-to-noise ratios of 300:1 and between 4% and 10% for spectra with signal-to-noise ratios of 100:1. The retrieval of atmospheric pressure increases the accuracy of the retrieved-gas concentrations by minimizing the effect of systematic errors introduced by climatological pressure data, ephemeris parameters, and the uncertainties in instrumental pointing. PMID:21085429

  17. ATMOS/ATLAS-3 Measurements of Stratospheric Chlorine and Reactive Nitrogen Partitioning Inside and Outside the November 1994 Antarctic Vortex

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Salawitch, R. J.; Michelsen, H. A.; Zander, R.; Newchurch, M. J.; Abbas, M. M.; Abrams, M. C.; Manney, G. L.; Chang, A. Y.; Irion, F. W.; Goldman, A.; Mahieu, E.

    1996-01-01

    Partitioning between HCl and ClONO2 and among the main components of the reactive nitrogen family (NO, NO2, HNO3, ClONO2, N2O5, and HO2NO2) has been studied inside and outside the Antarctic stratospheric vortex based on ATMOS profiles measured at sunrise during the 3-12 November 1994 ATLAS-3 Shuttle mission. Elevated mixing ratios of HCl in the lower stratosphere with a peak of approximately 2.9 ppbv (10(exp -9) parts per volume) were measured inside the vortex near 500 K potential temperature (approximately 19 km). Maximum ClONO2 mixing ratios of approximately 1.2, approximately 1.4, and approximately 0.9 ppbv near 700 K (approximately 25 km) were measured inside, at the edge, and outside the vortex, respectively. Model calculations reproduce the higher levels of HCl and NO(x) (NO + NO2) inside the lower stratospheric vortex both driven by photochemical processes initiated by low O3. The high HCl at low O3 results from chemical production of HC1 via the reaction of enhanced Cl with CH4, limited production of ClONO2, and the descent of inorganic chlorine from higher altitudes.

  18. Atmos/Atlas 3 Infrared Profile Measurements of Trace Gases in The November 1994 Tropical and Subtropical Upper Troposphere

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Wang, P.-H.; Arduini, R. F.; Baum, B. A.; Minnis, P.; Minnis, P.; Goldman, A.; Abrams, M. C.; Zander, R.; Mahieu, E.; Mahieu, E.; Salawitch, R. J.; Michelsen, H. A.; Irion, F. W.; Newchurch, M. J.

    1998-01-01

    Vertical mixing ratio profiles of four relatively long-lives gases, HCN, C2H2, CO, and C2H6, have been retrieved from 0.01/cm resolution infrared solar occultation spectra recorded between latitudes of 5.3degN and 31.4degN. The observations were obtained by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the Atmospheric Laboratory for Applications and Science (ATLAS) 3 shuttle flight, 3-12 November 1994. Elevated mixing ratios below the tropopause were measured for these gases during several of the occultations. The positive correlations obtained between the simultaneously measured mixing ratios suggest that the enhancements are likely the result of surface emissions, most likely biomass burning and/or urban industrial activities, followed by common injection via deep convective transport of the gases to the upper troposphere. The elevated levels of HCN may account for at least part of the "missing NO," in the upper troposphere. Comparisons of the observations with values measured during a recent aircraft campaign are presented.

  19. Middle and upper atmosphere pressure-temperature profiles and the abundances of CO2 and CO in the upper atmosphere from ATMOS/Spacelab 3 observations

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Zander, R.; Lopez-Puertas, M.

    1992-01-01

    An improved method for retrieving pressure-temperature profiles is described and is used to retrieve profiles of the kinetic-temperature and atmospheric-pressure profiles between 20 and 116 km altitudes and the CO2 and CO volume-mixing ratios between 70 and 116 km, using the IR occultation spectra recorded by the Spacelab 3 atmospheric trace molecular spectroscopy (ATMOS) Fourier transform spectrometer between April 29 and May 6, 1985. Profiles are derived for six ATMOS occultations. The CO2 and CO volume-mixing profiles are compared with previous observations and model predictions. Evidence is found for vibrational non-LTE by analyzing the lines of the (nu-2 + nu-3 - nu-2) (C-12)(O-16) band. Results are used for deriving (C-12)(O-16) (010) vibrational temperatures, which are compared with the retrieved kinetic temperatures and the predictions of non-LTE effects by recent models.

  20. Environment and microstructure effects on fatigue crack facet orientation in an Al-Li-Cu-Zr alloy

    SciTech Connect

    Slavik, D.C.; Gangloff, R.P.

    1996-09-01

    The effects of environment, microstructure and texture on transgranular fatigue crack facet orientation are established with electron-back scattered pattern analysis and stereofractography for single grains in peak aged Al-Li-Cu-Zr alloy 2090. For vacuum, facets are near-{l_brace}111{r_brace} due to fatigue fracture through intense deformation bands with a complex planar-slip dislocation structure. Multiple facets in single grains and the tortuous crack path are caused by high shear stresses resolved on multiple slip systems. Low stress intensity range fatigue fracture in NaCl is transgranular and faceted, but not tortuous. Eighty-five percent of the facets in unrecrystallized plate and 50% of the facets in recrystallized sheet are within 10 of a high index plane, on average {l_brace}521{r_brace}, subjected to high normal stresses. Such facets are inconsistent with: (a) hydrogen-enhanced localized plasticity and {l_brace}111{r_brace} decohesion; (b) slip-locking with bisecting {l_brace}100{r_brace} cracking; (c) environment-enhanced alternate slip with {l_brace}100{r_brace} faceting; or (d) {l_brace}100{r_brace}/{l_brace}100{r_brace} decohesion. Environmental fatigue may be governed by faceted cracking associated with hydrides or hydrogen embrittled dislocation cell walls.

  1. Fatigue crack growth of Ti-6Al-4V-0.1Ru (ELI grade) in ocean environments

    NASA Astrophysics Data System (ADS)

    Langoy, Morten Andre

    1999-11-01

    This study of fatigue crack growth rates found that Ti-6Al-4V-0.1Ru alloy seamless pipe in beta transformed/annealed condition is well suited for dynamically loaded risers, which transport the reservoir fluid (oil and gas) from the well to the vessel, and promises significant economic benefits can be realized by employing the material in this application. The tested ocean environments did not detrimentally affect crack growth rates. The material was studied in two conditions: as-received (i.e., the parent material) and cold rolled (simulating the effect of coiling and reeling). The effect of different combinations of loading and environment on fatigue crack growth rates of the parent and cold rolled materials were studied systematically using a design of experiments (DOE) approach. Different combinations of temperature, load frequency, R (sigmamin/sigmamax of the fatigue cycle), pre-strain (cold work), and environment (laboratory air and aerated and deaerated simulated ocean water) were used in the study. The observed fatigue crack growth rates ranged from 4 x 10 -10 to 1 x 10-6 m/cycle and the investigated DeltaK's (stress intensity ranges) ranged from 7 to 45 MPa√m. Fatigue crack growth rates are not substantially higher in ocean environments than in air, but the differences appear to be real. Cold work (5% reduction in thickness by rolling) reduces fatigue crack growth rates (compared to the parent material) at intermediate and high DeltaK by a factor of two. Microstructure, fracture surfaces, and crack path also were related to testing conditions. Fracture surfaces reveal a change of morphology from features associated with microstructure-sensitive crack propagation (cyclic cleavage) to features (striations) linked with structure-insensitive (continuum-mode) growth. Contrary to expectations based on anecdotal accounts, crack branching is observed at the center of the samples regardless of DeltaK or other parameters and also on the outer surfaces of the

  2. X-ray photoelectron spectroscopy and secondary electron yield analysis of Al and Cu samples exposed to an accelerator environment.

    SciTech Connect

    Rosenberg, R. A.; McDowell, M. W.; Ma, Q.; Harkay, K. C.; XFD; APS-USR; ASD

    2003-09-01

    It is well known that exposure to an accelerator environment can cause ''conditioning'' of the vacuum chamber surfaces. In order to understand the manner in which the surface structure might influence the production of gases and electrons in the accelerator, such surfaces should be studied both before and after exposure to accelerator conditions. Numerous studies have been performed on representative materials prior to being inserted into an accelerator, but very little has been done on materials that have ''lived'' in the accelerator for extended periods. In the present work, we mounted Al and Cu coupons at different positions in a section of the Advanced Photon Source storage ring and removed them following exposures ranging from 6 to 18 months. X-ray photoelectron spectroscopy (XPS) of the surface was performed before and after exposure. Changes were observed that depended on the location and whether the coupon was facing the chamber interior or chamber wall. These results will be presented and compared to XPS and secondary electron yield data obtained from laboratory measurements meant to simulate the accelerator conditions.

  3. Environment.

    ERIC Educational Resources Information Center

    White, Gilbert F.

    1980-01-01

    Presented are perspectives on the emergence of environmental problems. Six major trends in scientific thinking are identified including: holistic approaches to examining environments, life support systems, resource management, risk assessment, streamlined methods for monitoring environmental change, and emphasis on the global framework. (Author/SA)

  4. In-situ small-angle X-ray scattering study of the precipitation behavior in a Fe-25 at.%Co-9 at.%Mo alloy

    SciTech Connect

    Zickler, Gerald A. Eidenberger, Elisabeth; Leitner, Harald; Stergar, Erich; Clemens, Helmut; Staron, Peter; Lippmann, Thomas; Schreyer, Andreas

    2008-12-15

    Fe-Co-Mo alloys show extraordinary mechanical properties which make them potential candidates for various high-performance applications. In the present study, for the first time, the precipitation behavior in a Fe-25 at.%Co-9 at.%Mo alloy was studied by small-angle X-ray scattering using high-energy synchrotron radiation. The specimens were isothermally aged in an in-situ furnace. The small-angle X-ray scattering patterns showed scaling behavior and were evaluated by employing a model function from the literature. This approach provides information about the characteristic length scale and the volume fraction of the precipitates in the alloy.

  5. Professors' Perceptions of Distance Education in Virtual Environments: The Case of the Education Faculty of University of Al-Yarmouk (Jordan)

    ERIC Educational Resources Information Center

    Oassim-Al-shboul, Oassim Mahmoud; Sabiote, Clemente Rodriguez; Álvarez-Rodríguez, José

    2015-01-01

    The goal of this study is to determine the perceptions that the teaching staff of the Faculty of Education at University of Al-Yarmouk (Jordan) have of the implementation of distance learning in virtual environments, more specifically, the professors' opinion of the potential and limitations of this educational strategy. To fulfil this goal, we…

  6. Direct Observation of Lattice Aluminum Environments in Li Ion Cathodes LiNi1-y-zCoyAlzO2 and Al-Doped LiNixMnyCozO2 via (27)Al MAS NMR Spectroscopy.

    PubMed

    Dogan, Fulya; Vaughey, John T; Iddir, Hakim; Key, Baris

    2016-07-01

    Direct observations of local lattice aluminum environments have been a major challenge for aluminum-bearing Li ion battery materials, such as LiNi1-y-zCoyAlzO2 (NCA) and aluminum-doped LiNixMnyCozO2 (NMC). (27)Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy is the only structural probe currently available that can qualitatively and quantitatively characterize lattice and nonlattice (i.e., surface, coatings, segregation, secondary phase etc.) aluminum coordination and provide information that helps discern its effect in the lattice. In the present study, we use NMR to gain new insights into transition metal (TM)-O-Al coordination and evolution of lattice aluminum sites upon cycling. With the aid of first-principles DFT calculations, we show direct evidence of lattice Al sites, nonpreferential Ni/Co-O-Al ordering in NCA, and the lack of bulk lattice aluminum in aluminum-"doped" NMC. Aluminum coordination of the paramagnetic (lattice) and diamagnetic (nonlattice) nature is investigated for Al-doped NMC and NCA. For the latter, the evolution of the lattice site(s) upon cycling is also studied. A clear reordering of lattice aluminum environments due to nickel migration is observed in NCA upon extended cycling. PMID:27299505

  7. Seasonal Variations of Water Vapor in the Lower Stratosphere Inferred from ATMOS/ATLAS-3 Measurements of H2O and CH4

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Michelsen, H. A.; Gunson, M. R.; Abrams, M. C.; Newchurch, M. J.; Salawitch, R. J.; Chang, A. Y.; Goldman, A.; Irion, F. W.; Manney, G. L.; Moyer, E. J.; Nagaraju, R.; Rinsland, C. P.; Stiller, G. P.; Zander, R.

    1996-01-01

    Stratospheric measurements of H2O and CH4 by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer on the ATLAS-3 shuttle flight in November 1994 have been examined to investigate the altitude and geographic variability of H2O and the quantity H = (H2O + 2CH4) in the tropics and at mid-latitudes (8 to 49 deg N) in the northern hemisphere. The measurements indicate an average value of 7.24 plus or minus 0.44 ppmv for H between altitudes of about 18 to 35 km, corresponding to an annual average water vapor mixing ratio of 3.85 plus or minus 0.29 ppmv entering the stratosphere. The H2O vertical distribution in the tropics exhibits a wave-like structure in the 16- to 25-km altitude range, suggestive of seasonal variations in the water vapor transported from the troposphere to the stratosphere. The hygropause appears to be nearly coincident with the tropopause at the time of observations. This is consistent with the phase of the seasonal cycle of H2O in the lower stratosphere, since the ATMOS observations were made in November when the H2O content of air injected into the stratosphere from the troposphere is decreasing from its seasonal peak in July - August.

  8. On the Assessment and Uncertainty of Atmospheric Trace Gas Burden Measurements with High Resolution Infrared Solar Occultation Spectra from Space by the ATMOS Experiment

    NASA Technical Reports Server (NTRS)

    Abrams, M. C.; Chang, A. Y.; Gunson, M. R.; Abbas, M. M.; Goldman, A.; Irion, F. W.; Michelsen, H. A.; Newchurch, M. J.; Rinsland, C. P.; Stiller, G. P.; Zander, R.

    1996-01-01

    The Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument is a high resolution Fourier transform spectrometer that measures atmospheric composition from low Earth orbit with infrared solar occultation sounding in the limb geometry. Following an initial flight in 1985, ATMOS participated in the Atmospheric Laboratory for Applications and Science (ATLAS) 1, 2, and 3 Space Shuttle missions in 1992, 1993, and 1994 yielding a total of 440 occultation measurements over a nine year period. The suite of more than thirty atmospheric trace gases profiled includes CO2, O3, N2O, CH4, H2O, NO, NO2, HNO3, HCl, HF, ClONO2, CCl3F, CCl2F2, CHF2Cl, and N2O5. The analysis method has been revised throughout the mission years culminating in the 'version 2' data set. The spectroscopic error analysis is described in the context of supporting the precision estimates reported with the profiles; in addition, systematic uncertainties assessed from the quality of the spectroscopic database are described and tabulated for comparisons with other experiments.

  9. Seasonal Variations of Water Vapor in the Lower Stratosphere Inferred from ATMOS/ATLAS-3 Measurements of H2O and CH4

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Michelsen, H. A.; Gunson, M. R.; Abrams, M. C.; Newchurch, M. J.; Salawitch, R. J.; Chang, A. Y.; Goldman, A.; Irion, F. W.; Manney, G. L.; Moyer, E. J.; Nagaraju, R.; Rinsland, C. P.; Stiller, G. P.; Zander, R.

    1996-01-01

    Stratospheric measurements of H2O and CH4 by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer on the ATLAS-3 shuttle flight in November 1994 have been examined to investigate the altitude and geographic variability of H2O and the quantity H = (H2O + 2CH4) in the tropics and at mid-latitudes (8 to 49 deg N) in the northern hemisphere. The measurements indicate an average value of 7.24 +/- 0.44 ppmv for H between altitudes of about 18 to 35 km, corresponding to an annual average water vapor mixing ratio of 3.85 +/- 0.29 ppmv entering the stratosphere. The H2O vertical distribution in the tropics exhibits a wave-like structure in the 16- to 25-km altitude range, suggestive of seasonal variations in the water vapor transported from the troposphere to the stratosphere. The hygropause appears to be nearly coincident with the tropopause at the time of observations. This is consistent with the phase of the seasonal cycle of H2O in the lower stratosphere, since the ATMOS observations were made in November when the H2O content of air injected into the stratosphere from the troposphere is decreasing from its seasonal peak in July-August.

  10. ATMOS Measurements of H2O + 2CH4 and Total Reactive Nitrogen in the November 1994 Antarctic Stratosphere: Dehydration and Denitrification in the Vortex

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Gunson, M. R.; Salawitch, R. J.; Newchurch, M. J.; Zander, R.; Abbas, M. M.; Abrams, M. C.; Manney, G. L.; Michelsen, H. A.; Chang, A. Y.; Goldman, A.

    1996-01-01

    Simultaneous stratospheric volume mixing ratios (VMR's) measured inside and outside the Antarctic vortex by the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument in November 1994 reveal previously unobserved features in the distributions of total reactive nitrogen (NO(y)) and total hydrogen (H2O + 2CH4). Maximum removal of NO(y) due to sedimentation of polar stratospheric clouds (PSC's) inside the vortex occurred at a potential temperature (Theta) of 500-525 K (approximately 20 km), where values were 5 times smaller than measurements outside. Maximum loss of H2O + 2CH4 due to PSC's occurred in the vortex at 425-450 K, approximately 3 km lower than the peak NO(y) loss. At that level, H2O + 2CH4 VMR's inside the vortex were approximately 70% of corresponding values outside. The Antarctic and April 1993 Arctic measurements by ATMOS show no significant differences in H2O + 2CH4 VMR's outside the vortices in the two hemispheres. Elevated NO(y) VMRs were measured inside the vortex near 700 K. Recent model calculations indicate that this feature results from downward transport of elevated NO(y) produced in the thermosphere and mesosphere.

  11. Thermomechanical fatigue behavior of SiC/Ti-24Al-11Nb in air and argon environments

    NASA Technical Reports Server (NTRS)

    Bartolotta, Paul A.; Verrilli, Michael J.

    1992-01-01

    A series of tension-tension, load-controlled thermomechanical fatigue (TMF) tests were conducted on a titanium aluminide composite in both laboratory air and a flowing argon environment. Results from these tests show that the environment plays an increasingly important role as applied stress levels are decreased. Differences in damage mechanisms between the two environments were observed which corresponds to observed variations in TMF lives.

  12. Properties of a reaction-bonded β-SiAlON ceramic doped with an FeMo alloy for application to molten aluminum environments

    NASA Astrophysics Data System (ADS)

    Li, Yan-jun; Yu, Hai-liang; Jin, Hai-yun; Shi, Zhong-qi; Qiao, Guan-jun; Jin, Zhi-hao

    2015-05-01

    An FeMo-alloy-doped β-SiAlON (FeMo/β-SiAlON) composite was fabricated via a reaction-bonding method using raw materials of Si, Al2O3, AlN, FeMo, and Sm2O3. The effects of FeMo on the microstructure and mechanical properties of the composite were investigated. Some properties of the composite, including its bending strength at 700°C and after oxidization at 700°C for 24 h in air, thermal shock resistance and corrosion resistance to molten aluminum, were also evaluated. The results show that the density, toughness, bending strength, and thermal shock resistance of the composite are obviously improved with the addition of an FeMo alloy. In addition, other properties of the composite such as its high-temperature strength and oxidized strength are also improved by the addition of FeMo alloy, and its corrosion resistance to molten aluminum is maintained. These findings indicate that the developed FeMo/β-SiAlON composite exhibits strong potential for application to molten aluminum environments.

  13. Reply to discussion of "Tropospheric ozone variability over the Iberian Peninsula Atmospheric Environment" by Kulkarni et al. (2011)

    NASA Astrophysics Data System (ADS)

    Kulkarni, Pavan S.; Bortoli, D.; Salgado, R.; Antón, M.; Costa, M. J.; Silva, A. M.

    2011-05-01

    In the discussion paper on our article ( Kulkarni et al., 2011), de Laat has criticized TOR methodology and TOR data and thus questioned the validity of the findings. He has also pointed out the fact that the authors may have used the OMI/MLS data. In this reply to the discussion, the clarifications and references given herewith endeavour to undoubtedly answer the questions posed by de Laat on TOR methodology and on TOR data and thus proving that the findings of Kulkarni et al. (2011) are scientifically justified and therefore entirely valid. Furthermore, reasons were presented to justify the non use of the OMI/MLS data.

  14. Local environment and dynamics of PO4 tetrahedra in Na -Al-PO3 glasses and melts

    NASA Astrophysics Data System (ADS)

    Mamedov, S.; Stachel, D.; Soltwisch, M.; Quitmann, D.

    2005-09-01

    Glasses and melts in the system (NaPO3)(1-x)(Al(PO3)3)x were studied with the aim of obtaining information about the structure on the next larger scale beyond the PO4 group. Magic angle spinning NMR was applied to the pure NaPO3 glass and Raman scattering to systems with x =0.00, 0.03, 0.06, 0.15, and 0.60 in the temperature range T =300-1100K. Comparison of the P31 chemical shift between glass and crystalline forms revealed that polymerization of the metaphosphate into tricyclophosphatelike (PO3)33- rings is the dominant structure, ca. 80%, formed by the twofold vertex-joined PO4 groups in the glass. In the Raman study we focused on the prominent polarized band at ca. 1170cm-1 which is due to the symmetric breathing mode of the tetrahedral PO4 group. This band was decomposed into a few Gaussian lines. These component lines could be identified using the NMR results: two narrow components are due to PO4 groups in the tricyclophosphatelike rings, which have either a Na or an Al counterion and a third broad component is due to chain-polymerized (PO3-)n. The variations of the component lines (peak positions, widths, and intensities) with respect to x and T are presented. We derive the shifts of the symmetric breathing mode frequency which are caused by Na or Al counterions, by ring closure, by x >0, etc. The relative intensities of the narrow and broad components in the 1170-cm-1 band of the Raman spectra are discussed. The amount of ring-to-chain transformation on addition of Al3+, and as functions of T and x, is derived. Indications for ordering on a next larger scale, derivable from Raman, NMR, and thermodynamics, are compared.

  15. Performance of NiCrAlY Coatings Deposited by Oxyfuel Thermal Spraying in High Temperature Chlorine Environment

    NASA Astrophysics Data System (ADS)

    Habib, K. A.; Damra, M. S.; Carpio, J. J.; Cervera, I.; Saura, J. J.

    2014-10-01

    A microcrystalline Ni-22Cr-10Al-1Y (wt.%) coating was deposited on AISI 304 stainless steel by the oxyfuel thermal spray technique. The deposited coating was subjected to heat treatment to improve the microstructure characteristics and its corresponding high-temperature properties. The isothermal high-temperature corrosion behavior at 650 and 700 °C in synthetic air and in the presence of 1% Cl2 was investigated using thermogravimetric analysis, x-ray diffraction, and scanning electron microscopy with energy-dispersive x-ray spectroscopy. The results indicated that the deposited NiCrAlY coating possessed acceptable oxidation-corrosion resistance at 650 °C owing to the formation of extensive amounts of the protective oxide of Cr2O3; NiO and a lesser amount of a Cr1.12 Ni2,88 metallic phase are also formed. At 700 °C, the coating lost its protective characteristic because of the excessive consumption of thermodynamically stable phases by oxidation-chlorination process. In this case, the steel base and the coating were attacked by chlorine during the exposure time; the mass gain of the NiCrAlY coating was slightly higher and provided only a limited protection up to 11 h; thereafter, breakdown of the layer of oxides occurred and this is attributed to the formation of non-protective oxides mainly β-Fe2O3 and Fe21.33O32 and the depletion of chromium.

  16. Strength and corrosion behavior of a SiC particulate reinforced Al{sub 2}O{sub 3} composite in hot coal combustion environments

    SciTech Connect

    Breder, K.; Parten, R.J.; Canon, J.M. |

    1996-05-01

    As part of an effort to evaluate the use of advanced ceramics in a new generation of coal-fired power plants, a SiC particulate reinforced Al{sub 2}O{sub 3} has been exposed to corrosive coal slag in a laboratory furnace and two pilot scale caombustors. Results show increased corrosive attack with temperature and that only slight changes in temperature may significantly alter the degree of strength degradation due to corrosive attack. The present results are part of a larger experimental matrix evaluating the behavior of ceramics in the coal combustion environment.

  17. Corrigendum to "Re-examination of C1-C5 alkyl nitrates in Hong Kong using an observation-based model" [Atmos. Environ. 120 28-37

    NASA Astrophysics Data System (ADS)

    Lyu, X. P.; Ling, Z. H.; Guo, H.; Saunders, S. M.; Lam, S. H. M.; Wang, N.; Wang, Y.; Liu, M.; Wang, T.

    2016-03-01

    The authors regret the original version of this article unfortunately contained a mistake. A funding project number was wrong in the "Acknowledgements" on page 36. The correct "Acknowledgements" is as follows:

  18. Effect of Environment on the Scale Formed on ODS FeCrAl at 1050 C and 1100 C

    SciTech Connect

    Unocic, Kinga A; Essuman, Emmanuel K; Dryepondt, Sebastien N; Pint, Bruce A

    2012-01-01

    The surface scale formed on specimens of a commercial oxide dispersion strengthened (ODS) FeCrAl alloy (PM2000{trademark}) exposed for 1 and 500 h at 1050 C in dry O{sub 2}, Air + 10%H{sub 2}O and Ar + 10%H{sub 2}O consisted of a two-layer {alpha}-Al{sub 2}O{sub 3} structure with a columnar grain inner layer and a finer grain outer layer. The alumina scales formed in Air + 10%H{sub 2}O and Ar + 10%H{sub 2}O were slightly more than half of the thickness of the scale formed in dry O{sub 2}. The same two-layer structure was also observed after exposure for 500 h at 1100 C in dry O{sub 2} and 50%CO{sub 2} + 50%H{sub 2}O. The alumina scales formed in both atmospheres were similar in thickness. Oxides rich in Y and Ti at the gas - scale interface grew in size and number with time in each case. Using analytical transmission electron microscopy, alumina grain boundary segregation of both Y and Ti was evident near the gas interface but only Y segregation was detected near the metal interface. This difference was attributed to Ti depletion in the adjacent metal and the rapid outward flux of the smaller Ti ion through the scale.

  19. Constitutive Model for the Time-Dependent Mechanical Behavior of 430 Stainless Steel and FeCrAlY Foams in Sulfur-Bearing Environments

    SciTech Connect

    Hemrick, James Gordon; Lara-Curzio, Edgar

    2013-01-01

    The mechanical behavior of 430 stainless steel and pre-oxidized FeCrAlY open-cell foam materials of various densities was evaluated in compression at temperatures between 450 C and 600 C in an environment containing hydrogen sulfide and water vapor. Both materials showed negligible corrosion due to the gaseous atmosphere for up to 168 hours. The monotonic stress-strain response of these materials was found to be dependent on both the strain rate and their density, and the 430 stainless steel foam materials exhibited less stress relaxation than FeCrAlY for similar experimental conditions. Using the results from multiple hardening-relaxation and monotonic tests, an empirical constitutive equation was derived to predict the stress-strain behavior of FeCrAlY foams as a function of temperature and strain rate. These results are discussed in the context of using these materials in a black liquor gasifier to accommodate the chemical expansion of the refractory liner resulting from its reaction with the soda in the black liquor.

  20. Constitutive Model for the Time-Dependent Mechanical Behavior of 430 Stainless Steel and FeCrAlY Foams in Sulfur-Bearing Environments

    NASA Astrophysics Data System (ADS)

    Hemrick, James G.; Lara-Curzio, Edgar

    2013-03-01

    The mechanical behavior of 430 stainless steel and pre-oxidized FeCrAlY open-cell foam materials of various densities was evaluated in compression at temperatures between 450°C and 600°C in an environment containing hydrogen sulfide and water vapor. Both materials showed negligible corrosion due to the gaseous atmosphere for up to 168 h. The monotonic stress-strain response of these materials was found to be dependent on both the strain rate and their density, and the 430 stainless steel foam materials exhibited less stress relaxation than the FeCrAlY for similar experimental conditions. Using the results from multiple hardening-relaxation and monotonic tests, an empirical constitutive equation was derived to predict the stress-strain behavior of FeCrAlY foams as a function of temperature, and strain rate. These results are discussed in the context of using these materials in a black liquor gasifier to accommodate the chemical expansion of the refractory liner resulting from its reaction with the soda in the black liquor.

  1. Degradation of Ti-6Al-4V alloy under cyclic loading in a simulated body environment with cell culturing.

    PubMed

    Doi, Kotaro; Miyabe, Sayaka; Tsuchiya, Hiroaki; Fujimoto, Shinji

    2016-03-01

    The present study reports the corrosion fatigue of the Ti-6Al-4V alloy using cyclic deformation test in a simulated body fluid under cell culturing for the first time. Cyclic deformation tests were carried out using three types of specimens to reveal the effects of proteins and cells on the corrosion fatigue of the alloy. For the 1-day-immersed and 1-week-immersed specimens, tensile specimens were soaked in a simulated body fluid for 1 day and 1 week, respectively, before cyclic deformation test, whereas for the cell-cultured specimen, MC3T3-E1 osteoblast-like cells were seeded and then cultured on tensile specimens for 1 week. The incubation period for crack initiation was longer for the cell-cultured and 1-week-immersed specimens compared to that for the 1-day-immersed specimen. On the other hand, crack propagation period for the cell-cultured and 1-week-immersed specimens was shorter than that for the 1-day-immersed specimen. These results indicate that proteins and cells adhered on the alloy surface inhibit metal dissolution at newly created surface emerged by cyclic deformation to suppress crack initiation, whereas they accelerate crack propagation because dissolution at crack tip is accelerated in the occluded space formed under proteins and cells. PMID:26651063

  2. Continuous and discontinuous precipitation in Fe-1 at.%Cr-1 at.%Mo alloy upon nitriding; crystal structure and composition of ternary nitrides

    NASA Astrophysics Data System (ADS)

    Steiner, Tobias; Ramudu Meka, Sai; Rheingans, Bastian; Bischoff, Ewald; Waldenmaier, Thomas; Yeli, Guma; Martin, Tomas L.; Bagot, Paul A. J.; Moody, Michael P.; Mittemeijer, Eric J.

    2016-05-01

    The internal nitriding response of a ternary Fe-1 at.%Cr-1 at.%Mo alloy, which serves as a model alloy for many CrMo-based steels, was investigated. The nitrides developing upon nitriding were characterised by X-ray diffraction, scanning electron microscopy, electron probe microanalysis, transmission electron microscopy and atom probe tomography. The developed nitrides were shown to be (metastable) ternary mixed nitrides, which exhibit complex morphological, compositional and structural transformations as a function of nitriding time. Analogous to nitrided binary Fe-Cr and Fe-Mo alloys, in ternary Fe-Cr-Mo alloys initially continuous precipitation of fine, coherent, cubic, NaCl-type nitride platelets, here with the composition (Cr½,Mo½)N¾, occurs, with the broad faces of the platelets parallel to the {1 0 0}α-Fe lattice planes. These nitrides undergo a discontinuous precipitation reaction upon prolonged nitriding leading to the development of lamellae of a novel, hexagonal CrMoN2 nitride along {1 1 0}α-Fe lattice planes, and of spherical cubic, NaCl-type (Cr,Mo)Nx nitride particles within the ferrite lamellae. The observed structural and compositional changes of the ternary nitrides have been attributed to the thermodynamic and kinetic constraints for the internal precipitation of (misfitting) nitrides in the ferrite matrix.

  3. High resolution infrared spectroscopy from space: A preliminary report on the results of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment on Spacelab 3

    NASA Technical Reports Server (NTRS)

    Farmer, Crofton B.; Raper, Odell F.

    1987-01-01

    The ATMOS (Atmospheric Trace Molecule Spectroscopy) experiment has the broad purpose of investigating the physical structure, chemistry, and dynamics of the upper atmosphere through the study of the distributions of the neutral minor and trace constituents and their seasonal and long-term variations. The technique used is high-resolution infrared absorption spectroscopy using the Sun as the radiation source, observing the changes in the transmission of the atmosphere as the line-of-sight from the Sun to the spacecraft penetrates the atmosphere close to the Earth's limb at sunrise and sunset. During these periods, interferograms are generated at the rate of one each second which yield, when transformed, high resolution spectra covering the 2.2 to 16 micron region of the infrared. Twenty such occultations were recorded during the Spacelab 3 flight, which have produced concentration profiles for a large number of minor and trace upper atmospheric species in both the Northern and Southern Hemispheres. Several of these species have not previously been observed in spectroscopic data. The data reduction and analysis procedures used following the flight are discussed; a number of examples of the spectra obtained are shown, and a bar graph of the species detected thus far in the analysis is given which shows the altitude ranges for which concentration profiles were retrieved.

  4. Measurements of CH4, N2O, CO, H2O and O3 in the middle atmosphere by the ATMOS experiment on Spacelab 3

    NASA Technical Reports Server (NTRS)

    Gunson, M. R.; Farmer, C. B.; Norton, R. H.; Zander, R.; Rinsland, C. P.; Shaw, J. H.; Gao, Bo-Cai

    1989-01-01

    The volume mixing ratios of five minor gases (CH4, N2O, CO, H2O, and O3) were retrieved through the middle atmosphere from the analysis of 0.01/cm resolution infrared solar occultation spectra recorded near 28 N and 48 S latitudes with the ATMOS (Atmospheric Trace Molecule Spectroscopy) instrument, flown on board Spacelab 3. The results, which constitute the first simultaneous observations of continuous profiles through the middle atmosphere for these gases, are in general agreement with reported measurements from ground, balloon and satellite-based instruments for the same seasons. In detail, the vertical profiles of these gases show the effects of the upper and middle atmospheric transport patterns dominant during the season of these observations. The profiles inferred at different longitudes around 28 N suggest a near-uniform zonal distribution of these gases. Although based on fewer observations, the sunrise occultation measurements point to a larger variability in the vertical distribution of these gases at 48 S.

  5. Environmental fatigue of an Al-Li-Cu alloy. I - Intrinsic crack propagation kinetics in hydrogenous environments

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Gangloff, Richard P.

    1991-01-01

    Deleterious environmental effects on steady-state, intrinsic fatigue crack propagation (FCP) rates (da/dN) in peak aged Al-Li-Cu alloy 2090 are established by electrical potential monitoring of short cracks with programmed constant delta K and K(sub max) loading. The da/dN are equally unaffected by vacuum, purified helium, and oxygen but are accelerated in order of decreasing effectiveness of aqueous 1 percent NaCl with anodic polarization, pure water vapor, moist air, and NaCl with cathodic polarization. While da/dN depends on delta K(sup 4.0) for the inert gases, water vapor and chloride induced multiple power-laws, and a transition growth rate 'plateau'. Environmental effects are strongest at low delta K. Crack tip damage is ascribed to hydrogen embrittlement because of the following: (1) accelerated da/dN due to part-per-million levels of H2O without condensation; (2) impeded molecular flow model predictions of the measured water vapor pressure dependence of da/dN as affected by mean crack opening; (3) the lack of an effect of film-forming O2; (4) the likelihood for crack tip hydrogen production in NaCl; and (5) the environmental and delta K-process zone volume dependencies of the microscopic cracking modes. For NaCl, growth rates decrease with decreasing loading frequency, with the addition of passivating Li2CO3, and upon cathodic polarization. These variables increase crack surface film stability to reduce hydrogen entry efficiency. The hydrogen environmental FCP resistance of 2090 is similar to other 2000 series alloys and is better than 7075.

  6. Environmental fatigue of an Al-Li-Cu alloy. Part 1: Intrinsic crack propagation kinetics in hydrogenous environments

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Gangloff, Richard P.

    1991-01-01

    Deleterious environmental effects on steady-state, intrinsic fatigue crack propagation (FCP) rates (da/dN) in peak aged Al-Li-Cu alloy 2090 are established by electrical potential monitoring of short cracks with programmed constant delta K and K(sub max) loading. The da/dN are equally unaffected by vacuum, purified helium, and oxygen but are accelerated in order of decreasing effectiveness by aqueous 1 percent NaCl with anodic polarization, pure water vapor, moist air, and NaCl with cathodic polarization. While da/dN depends on delta K(sup 4.0) for the inert gases, water vapor and chloride induced multiple power-laws, and a transition growth rate 'plateau'. Environmental effects are strongest at low delta K. Crack tip damage is ascribed to hydrogen embrittlement because of the following: (1) accelerated da/dN due to part-per-million levels of H2O without condensation; (2) impeded molecular flow model predictions of the measured water vapor pressure dependence of da/dN as affected by mean crack opening; (3) the lack of an effect of film-forming O2; (4) the likelihood for crack tip hydrogen production in NaCl, and (5) the environmental and delta K-process zone volume dependencies of the microscopic cracking modes. For NaCl, growth rates decrease with decreasing loading frequency, with the addition of passivating Li2CO3, and upon cathodic polarization. These variables increase crack surface film stability to reduce hydrogen entry efficiency. The hydrogen environmental FCP resistance of 2090 is similar to other 2000 series alloys and is better than 7075.

  7. Tribocorrosive behaviour of commonly used temporomandibular implants in a synovial fluid-like environment: Ti-6Al-4V and CoCrMo

    NASA Astrophysics Data System (ADS)

    Royhman, D.; Yuan, J. C.; Shokuhfar, T.; Takoudis, C.; Sukotjo, C.; Mathew, M. T.

    2013-10-01

    The temporomandibular joint implant metal alloys, Ti6Al4V and CoCrMo, (n = 3/group) were tested under free-potential and potentiostatic conditions using a custom-made tribocorrosion apparatus. Sliding duration (1800 cycles), frequency (1.0 Hz) and load (16 N) mimicked the daily mastication process. Synovial-like fluid (bovine calf serum, pH = 7.6 at 37 °C) was used to simulate the in vivo environment. Changes in friction coefficient were monitored throughout the sliding process. Changes in surface topography, total weight loss and roughness values were calculated using scanning electron microscopy and white-light interferometry. Finally, statistical analyses were performed using paired t-tests to determine significance between regions within each metal type and also independent sample t-tests to determine statistical significance between metal alloy types. Ti6Al4V demonstrated a greater decrease of potential than CoCrMo, a higher weight loss from wear (Kw = 257.8 versus 2.62 µg p < 0.0001), a higher weight loss from corrosion (Kc = 17.44 versus 0.14 µg p < 0.0001) and a higher weight loss from the combined effects of wear and corrosion (Kwc = 275.28 versus 2.76 µg p < 0.0001). White-light interferometry measurements demonstrated a greater difference in surface roughness inside the wear region in Ti6Al4V than CoCrMo after the sliding (Ra = 323.80 versus 70.74 nm p < 0.0001). In conclusion, CoCrMo alloy shows superior anti-corrosive and biomechanical properties.

  8. Stratospheric Observations of CH3D and HDO from ATMOS Infrared Solar Spectra: Enrichments of Deuterium in Methane and Implications for HD

    NASA Technical Reports Server (NTRS)

    Irion, F. W.; Moyer, E. J.; Gunson, M. R.; Rinsland, C. P.; Yung, Y. L.; Michelsen, H. A.; Salawitch, R. J.; Chang, A. Y.; Newchurch, M. J.; Abbas, M. M.; Abrams, M. C.; Zander, R.

    1996-01-01

    Stratospheric mixing ratios of CH3D from 100 mb to 17mb (approximately equals 15 to 28 km)and HDO from 100 mb to 10 mb (approximately equals 15 to 32 km) have been inferred from high resolution solar occultation infrared spectra from the Atmospheric Trace MOlecule Spectroscopy (ATMOS) Fourier-transform interferometer. The spectra, taken on board the Space Shuttle during the Spacelab 3 and ATLAS-1, -2, and -3 missions, extend in latitude from 70 deg S to 65 deg N. We find CH3D entering the stratosphere at an average mixing ratio of (9.9 +/- 0.8) x 10(exp -10) with a D/H ratio in methane (7.1 +/- 7.4)% less than that in Standard Mean Ocean Water (SMOW) (1 sigma combined precision and systematic error). In the mid to lower stratosphere, the average lifetime of CH3D is found to be (1.19 +/- 0.02) times that of CH4, resulting in an increasing D/H ratio in methane as air 'ages' and the methane mixing ratio decreases. We find an average of (1.0 +/- 0.1) molecules of stratospheric HDO are produced for each CH3D destroyed (1 sigma combined precision and systematic error), indicating that the rate of HDO production is approximately equal to the rate of CH3D destruction. Assuming negligible amounts of deuterium in species other than HDO, CH3D and HD, this limits the possible change in the stratospheric HD mixing ratio below about 10 mb to be +/- 0.1 molecules HD created per molecule CH3D destroyed.

  9. An in situ Al K-edge XAS investigation of the local environment of H+- and Cu+-exchanged USY and ZSM-5 zeolites.

    PubMed

    Drake, Ian J; Zhang, Yihua; Gilles, Mary K; Teris Liu, C N; Nachimuthu, Ponnusamy; Perera, Rupert C C; Wakita, Hisanobu; Bell, Alexis T

    2006-06-22

    Aluminum coordination in the framework of USY and ZSM-5 zeolites containing charge-compensating cations (NH4+, H+, or Cu+) was investigated by Al K-edge EXAFS and XANES. This work was performed using a newly developed in-situ cell designed especially for acquiring soft X-ray absorption data. Both tetrahedrally and octahedrally coordinated Al were observed for hydrated H-USY and H-ZSM-5, in good agreement with 27Al NMR analyses. Upon dehydration, water desorbed from the zeolite, and octahedrally coordinated Al was converted progressively to tetrahedrally coordinated Al. These observations confirmed the hypothesis that the interaction of water with Brønsted acid protons can lead to octahedral coordination of Al without loss of Al from the zeolite lattice. When H+ is replaced with NH4+ or Cu+, charge compensating species that absorb less water, less octahedrally coordinated Al was observed. Analysis of Al K-edge EXAFS data indicates that the Al-O bond distance for tetrahedrally coordinated Al in dehydrated USY and ZSM-5 is 1.67 angstroms. Simulation of k3chi(k) for Cu+ exchanged ZSM-5 leads to an estimated distance between Cu+ and framework Al atoms of 2.79 angstroms. PMID:16800461

  10. Theoretical investigation on local structure and transport properties of NaFsbnd AlF3 molten salts under electric field environment

    NASA Astrophysics Data System (ADS)

    Lv, Xiaojun; Xu, Zhenming; Li, Jie; Chen, Jiangan; Liu, Qingsheng

    2016-08-01

    The effect of electric field and molecular ratio CR (NaF/AlF3) on basic structure and transport properties of NaFsbnd AlF3 molten salts were investigated by molecular dynamics simulations with the Buckingham potential model. The [AlF6]3- groups are the dominant specie in NaFsbnd AlF3 molten salts at CR ≥ 2.6, and followed by the [AlF5]2- groups, while CR ≤ 2.4, [AlF5]2- groups are the protagonists up to 40%. In NaFsbnd AlF3 system, with the increase of CR, the proportion of Fb decreases slightly and the percentage of Ff increases dramatically. The Alsbnd F bonds have ionic characters as well as partial covalently characters due to the hybridization of F-2p and Al-3s, 3p orbitals. The order of ion diffusion ability follows as Na+ > F- > Al3+. Adding more NaF can break some F bridges of structure networks and decrease the polymerization degree of NaFsbnd AlF3 molten salts, the viscosity reduces and ionic conductivity increases as a consequence. The calculated results of ionic conductivity are in agreement with the experimental results. Electric field has no significant impact on the local structure characters, while transport properties are not. The change of CR (NaF/AlF3) can significantly affect these characters of both the structure and transport.

  11. Response to "using of 'pseudo-second-order model' in adsorption", comment letter on "phenol removal from wastewater by adsorption on zeolitic composite" [Bizerea Spiridon et al., Environ Sci Pollut Res (2013) 20:6367-6381].

    PubMed

    Bizerea Spiridon, Otilia; Pitulice, Laura

    2014-01-01

    This letter is a response to the issues put forth by Dr. Y.S. Ho with regard to the article "Phenol removal from wastewater by adsorption on zeolitic composite" as reported by Bizerea Spiridon et al. (Environ Sci Pollut Res 20:6367-6381, 2013). The response proposes to clarify the error slipped in the typewritten linearized equation of the pseudo-second-kinetic model and the reason for using secondary reference regarding this model. PMID:24638835

  12. Al-tobermorite in Pyroclastic Rock-Seawater Environments: 1963-1967 Surtsey Tephra and 2000-year-old Roman Baianus Sinus Harbor Concrete

    NASA Astrophysics Data System (ADS)

    Jackson, M. D.; Moore, J. G.; Wenk, H.; Monteiro, P. J.

    2012-12-01

    Interaction of basaltic tephra from the 1963-1967 Surtsey eruptions in Iceland with 70-150 °C seawater produced authigenic zeolites and Al-tobermorite, a layered calcium-aluminum-silicate-hydrate mineral that holds promise as a cementitious binder for environmentally-friendly concretes and concrete encapsulations of hazardous wastes, but has never been recognized in conventional portland cement concretes. A Roman concrete breakwater, or pilae, constructed of lime and Campi Flegrei pyroclastic rock in the 14-26°C seawater of Pozzuoli Bay (Baianus Sinus) in first century BCE, however, developed Al-tobermorite in relict lime clasts, Neapolitan Yellow Tuff pumice fragments, and voids, forming about 5-10 volume% of the pozzolanic mortar. A thermal model of the 10m2 by 6m tall pilae indicates that exothermic hydration of portlandite and poorly-crystalline calcium-aluminum-silicate-hydrate (C-A-S-H) cementitious binder produced maximum adiabatic temperatures <85 °C, 28-90 days after installation. Relative to Surtsey Al-tobermorite, Baianus Sinus Al-tobermorite in relict lime clasts is enriched in aluminum and calcium, with Al/(Si+Al)=0.16-0.17 and Ca/(Si+Al)=0.83. This is likely the result of saturation with respect to portlandite at pH>12.7, and high Al3+mobility in a system infused with silicon, aluminum, sodium and potassium from the alkali-rich Flegrean ash, with sulfate and chloride from seawater acting as possible mineralizers. Synchrotron-radiation soft X-ray microscopy and NMR studies indicate that Baianus Sinus Al-tobermorite has a double-silicate-chain structure with aluminum substitution for silicon in tetrahedral chain and branching sites, and a large 11.44(3) Å interlayer spacing. The bulk modulus measured from high pressure synchroton X-ray diffraction experiments, 54.7±5.5 GPa, is ~20 GPa greater than modern C-A-S-H. Na2O and K2O at 0.3-1.2 weight% partially balance Al3+ substitution for Si4+ in both the Surtsey and Baianus Sinus crystals. Sulphate and

  13. Reply to comment by Ben-Zvi, A., D. Rosenfeld and A. Givati on the paper: Levin, Z., N. Halfon and P. Alpert, “Reassessment of rain experiments and operations in Israel including synoptic considerations,” Atmos. Res. 97, 513-525. DOI: 10.1016/j.atmosres.2010.06.011

    NASA Astrophysics Data System (ADS)

    Levin, Zev; Halfon, Noam; Alpert, Pinhas

    2011-03-01

    Levin et al. (2010; hereafter LHA) (Levin, Z., Halfon, N., Alpert, P., 2010. Reassessment of rain experiments and operations in Israel including synoptic considerations. Atmos. Res. 97, 513-525. DOI:10.1016/j.atmosres.2010.06.011.), reanalyzed the results of the operational seeding in northern Israel between 1975 and 2007 and the preceding Israel 2 cloud seeding experiment (1969-1975) and concluded that there is no net increase in precipitation over the target areas. Our analysis revealed that a synoptic bias during Israel 2 is one of the reasons for the apparent positive effect of seeding in the northern target area and the negative effect in the southern area both of which disappeared in the following experiment in the south (Israel 3; 1975-1995) and the operational seeding in the north. Ben-Zvi et al. (2010;hereafter BRG) criticized our paper primarily on the ground that we did not consider the positive results of Israel 1 experiment (1960-1967). It should be noted that in Israel 1 different seeding lines were used from those in both Israel 2 and the operational period. In addition, its raw data is not accessible anymore for reanalysis. Furthermore, Israel 2 had been designed as a confirmatory cross-over experiment to Israel 1 and failed to reproduce its promising results with double ratio (DR) of ~ 1.00, namely, zero rainfall enhancements. The same DR values were also found in Israel 3 and in the operational seeding. Therefore, because of the differences in the two experiments, the lack of access to the raw data and the disappointing results of the confirmatory experiment, we decided to concentrate our analysis on the more recent seeding activities. The attempt by BRG to explain the reduction of the DR to ~ 1.00 in the operational seeding period by the suppression due to pollution have been disproved by Alpert et al. (2008, 2009) and also fail to explain the sharp decline of the target/control ratio right at the beginning of the operational seeding period when

  14. Sacrificial anode stability and polarization potential variation in a ternary Al-xZn-xMg alloy in a seawater-marine environment

    NASA Astrophysics Data System (ADS)

    Muazu, Abubakar; Aliyu, Yaro Shehu; Abdulwahab, Malik; Idowu Popoola, Abimbola Patricia

    2016-04-01

    In this paper, the effects of zinc (Zn) and magnesium (Mg) addition on the performance of an aluminum-based sacrificial anode in seawater were investigated using a potential measurement method. Anodic efficiency, protection efficiency, and polarized potential were the parameters used. The percentages of Zn and Mg in the anodes were varied from 2% to 8% Zn and 1% to 4% Mg. The alloys produced were tested as sacrificial anodes for the protection of mild steel in seawater at room temperature. Current efficiency as high as 88.36% was obtained in alloys containing 6% Zn and 1% Mg. The polarized potentials obtained for the coupled (steel/Al-based alloys) are as given in the Pourbaix diagrams, with steel lying within the immunity region/cathodic region and the sacrificial anodes within the anodic region. The protection offered by the sacrificial anodes to the steel after the 7th and 8th week was measured and protection efficiency values as high as 99.66% and 99.47% were achieved for the Al-6%Zn-1%Mg cast anode. The microstructures of the cast anodes comprise of intermetallic structures of hexagonal Mg3Zn2 and body-centered cubic Al2Mg3Zn3. These are probably responsible for the breakdown of the passive alumina film, thus enhancing the anode efficiency.

  15. Sacrificial anode stability and polarization potential variation in a ternary Al-xZn-xMg alloy in a seawater-marine environment

    NASA Astrophysics Data System (ADS)

    Muazu, Abubakar; Aliyu, Yaro Shehu; Abdulwahab, Malik; Idowu Popoola, Abimbola Patricia

    2016-06-01

    In this paper, the effects of zinc (Zn) and magnesium (Mg) addition on the performance of an aluminum-based sacrificial anode in seawater were investigated using a potential measurement method. Anodic efficiency, protection efficiency, and polarized potential were the parameters used. The percentages of Zn and Mg in the anodes were varied from 2% to 8% Zn and 1% to 4% Mg. The alloys produced were tested as sacrificial anodes for the protection of mild steel in seawater at room temperature. Current efficiency as high as 88.36% was obtained in alloys containing 6% Zn and 1% Mg. The polarized potentials obtained for the coupled (steel/Al-based alloys) are as given in the Pourbaix diagrams, with steel lying within the immunity region/cathodic region and the sacrificial anodes within the anodic region. The protection offered by the sacrificial anodes to the steel after the 7th and 8th week was measured and protection efficiency values as high as 99.66% and 99.47% were achieved for the Al-6%Zn-1%Mg cast anode. The microstructures of the cast anodes comprise of intermetallic structures of hexagonal Mg3Zn2 and body-centered cubic Al2Mg3Zn3. These are probably responsible for the breakdown of the passive alumina film, thus enhancing the anode efficiency.

  16. The spectacular evolution of Supernova 1996al over 15 yr: a low-energy explosion of a stripped massive star in a highly structured environment

    NASA Astrophysics Data System (ADS)

    Benetti, S.; Chugai, N. N.; Utrobin, V. P.; Cappellaro, E.; Patat, F.; Pastorello, A.; Turatto, M.; Cupani, G.; Neuhäuser, R.; Caldwell, N.; Pignata, G.; Tomasella, L.

    2016-03-01

    Spectrophotometry of SN 1996al carried out throughout 15 yr is presented. The early photometry suggests that SN 1996al is a linear Type II supernova, with an absolute peak of MV ˜ -18.2 mag. Early spectra present broad asymmetric Balmer emissions, with superimposed narrow lines with P-Cygni profile, and He I features with asymmetric broad emission components. The analysis of the line profiles shows that the H and He broad components form in the same region of the ejecta. By day +142, the Hα profile dramatically changes: the narrow P-Cygni profile disappears, and the Hα is fitted by three emission components that will be detected over the remaining 15 yr of the supernova (SN) monitoring campaign. Instead, the He I emissions become progressively narrower and symmetric. A sudden increase in flux of all He I lines is observed between 300 and 600 d. Models show that the SN luminosity is sustained by the interaction of low-mass (˜1.15 M⊙) ejecta, expelled in a low kinetic energy (˜1.6 × 1050 erg) explosion, with highly asymmetric circumstellar medium. The detection of Hα emission in pre-explosion archive images suggests that the progenitor was most likely a massive star (˜25 M⊙ ZAMS) that had lost a large fraction of its hydrogen envelope before explosion, and was hence embedded in a H-rich cocoon. The low-mass ejecta and modest kinetic energy of the explosion are explained with massive fallback of material into the compact remnant, a 7-8-M⊙ black hole.

  17. Staying connected: neighbourhood correlates of social participation among older adults living in an urban environment in Montréal, Quebec.

    PubMed

    Richard, Lucie; Gauvin, Lise; Gosselin, Céline; Laforest, Sophie

    2009-03-01

    Alongside community involvement, promoting social participation has been identified as a key strategy of fostering empowerment, one of the central tenets of the health promotion movement. Engagement in social and productive activities appears to be particularly beneficial to older adults, as it has been found to be associated with positive outcomes on a variety of health indicators. It is therefore critical to identify factors that might lead to greater social participation within these age groups. The objective of this study was to investigate the relationship between perceptions of neighbourhood user-friendliness and social participation while controlling for personal characteristics in a sample of seniors living in an urban environment. A convenience sample of older adults (n = 282) was recruited through community organizations located in high- average- and low-income Montreal neighbourhoods. Data were collected via an interviewer-administered questionnaire assessing social participation and various variables at the neighbourhood level (e.g. housing and social environment, walking environment and transportation, and services and amenities) and at the individual-level (e.g. health status and socio-demographic characteristics). Five variables emerged as independent predictors of social participation. Positive predictors retained in the final regression model included frequent walking episodes (almost every day), higher Vitality and General Health SF-12v2 scores, and perceived accessibility to key resources for older adults. Also included was a negative predictor: age (R2 of the final model = 0.28). Implications of the findings for research and action pertaining to ecological, health promotion interventions for older adults are identified. PMID:19098293

  18. Corrosion behavior of coated 2 1/4 Cr-1Mo and mild steel substrates in a simulated waste heat recovery system environment of a coal gasifier. [FeCrAl or CoCrAl alloys and pack-diffusion aluminizing or chromizing

    SciTech Connect

    Baxter, D.J.

    1985-07-01

    Cossosion tests have been conducted on coated 2 1/4Cr-1Mo and A106 mild steel in a gaseous environment typical of that expected in a downstream waste-heat recovery system of a coal gasifier. The environment contained controlled oxygen and sulfur levels, and the tests were run in a rig designed to expose specimens under simulated heat-exchanger conditions. Uncoated steel substrates exhibited breakaway corrosion behavior. Furnace-fused coatings of FeCrAl or CoCrAl alloys contained numerous defects, such as voids and cracks, and subsequently underwent substantial degradation during exposure. Coatings containing the stable oxide-forming elements Al and Cr were also applied by pack diffusion processes. Sequential chromizing of the A106 mild steel could not be achieved due to massive Cr carbide formation in the initial chromizing stage. Sequential chromizing/aluminizing of the 2 1/4Cr-1Mo steel was successful, but the coating contained numerous defects, which permitted considerable attack of the coated substrate. Simultaneous aluminizing/chromizing produced mixed results, depending upon the particular process used in applying the coating. Coatings exhibited behavior ranging from protective to complete breakdown. A solid FeCrAlY alloy exhibited protective oxidation behavior. With respect to joining or repair methods for coated steels, four different weld metals were used to simulate joining or repair operations of prior aluminized steel substrates. The Ni-base Inconel 625 weld showed good corrosion resistance with Inconel 72 sustaining minor internal attack. The Co-base L605 and Fe-base 309 SS weld metals exhibited breakaway corrosion characterized by the formation of thick scales and deep internal attack. 19 refs., 21 figs., 3 tabs.

  19. Ground-Based Testing of TiB2 and Al2O3/TiB2 Response to Space Environment

    NASA Technical Reports Server (NTRS)

    Jefferies, Sharon A.; Logan, Kathryn V.

    2007-01-01

    Two materials, titanium diboride and an alumina/titanium diboride composite, exhibit characteristics favorable for use in multiple space applications. These characteristics include low mass (4.52 gm/cc), high strain rate impact resistance, high temperature use (3000oC M.P.), thermal and electrical conductivity, thermal shock resistance, and high visible-range reflectivity. Additionally, the presence of boron in these materials gives them the potential to shield against neutron radiation as well as charged radiation. These materials are flying on MISSE 6 to assess material changes resulting from exposure to the space environment. This study provides a preliminary, ground-based examination of these materials' interactions with individual components of the space environment, in particular atomic oxygen (AO) and neutron radiation, in order to better predict and understand post-flight results. Individual specimens are exposed to ground state AO and surface oxidation is measured. Equivalent exposures of up to 13 months show no rapid oxidation, however evidence indicates some surface oxidation occurring. Other samples are placed near a polyethylene moderated, one Ci Am/Be neutron source to determine their shielding capability. Comparisons between exposed and shielded indium foil, which is activated by transmitted neutrons, measure each material's ability to shield neutrons. Preliminary results indicate a significant shielding benefit provided by both materials.

  20. ALS - resources

    MedlinePlus

    Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association -- mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) Registry -- ...

  1. ALS Association

    MedlinePlus

    ... ALS. Find Out How Our Mission Leading the fight to treat and cure ALS through global research ... you participate, advocate, and donate, you advance the fight to find the cure and lead us toward ...

  2. Everyday Life with ALS: A Practical Guide

    MedlinePlus

    ... course of ALS. ALS also will require some adaptations to your environment, both for safety and to ... the way, Chapter 6 will include information on adaptations for computer access. Though the chapter is called “ ...

  3. Scratch and wear behaviour of plasma sprayed nano ceramics bilayer Al2O3-13 wt%TiO2/hydroxyapatite coated on medical grade titanium substrates in SBF environment

    NASA Astrophysics Data System (ADS)

    Palanivelu, R.; Ruban Kumar, A.

    2014-10-01

    Among the various coating techniques, plasma spray coating is an efficient technique to protect the metal surface from the various surface problems like wear and corrosion. The aim of this present work is to design and produce a bilayer coating on the non- toxic commercially pure titanium (denoted as CP-Ti) implant substrate in order to improve the biocompatibility and surface properties. To achieve that, Al2O3-13 wt%TiO2 (AT13) and hydroxyapatite (HAP) were coated on CP-Ti implant substrate using plasma spray coating technique. Further, the coated substrates were subjected to various characterization techniques. The crystallite size of coated HAP and its morphological studies were carried out using X-ray diffractometer (XRD) and scanning electron microscopy (SEM) respectively. The wear test on the bilayer (AT13/HAP) coated CP-Ti implant surface was conducted using ball-on-disc tester under SBF environment at 37 °C, in order to determine the wear rate and the coefficient of friction. The adhesion strength of the bilayer coated surface was evaluated by micro scratch tester under the ramp load conditions with load range of 14-20 N. The above said studies were repeated on the single layer coated HAP and AT13 implant surfaces. The results reveal that the bilayer (AT13/HAP) coated CP-Ti surface has the improved wear rate, coefficient of friction in compared to single layer coated HAP and AT13 surfaces.

  4. X-ray computed microtomography of sea ice - comment on "A review of air-ice chemical and physical interactions (AICI): liquids, quasi-liquids, and solids in snow" by Bartels-Rausch et al. (2014)

    NASA Astrophysics Data System (ADS)

    Obbard, R. W.

    2015-07-01

    This comment addresses a statement made in "A review of air-ice chemical and physical interactions (AICI): liquids, quasi-liquids, and solids in snow" by Bartels-Rausch et al. (Atmos. Chem. Phys., 14, 1587-1633, doi:10.5194/acp-14-1587-2014, 2014). Here we rebut the assertion that X-ray computed microtomography of sea ice fails to reveal liquid brine inclusions by discussing the phases present at the analysis temperature.

  5. Al Composites

    NASA Astrophysics Data System (ADS)

    Chandanayaka, Tharaka; Azarmi, Fardad

    2014-05-01

    In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% Ni3Al particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different Ni3Al powders with nominal particle size of -45 to +5 and +45 to 100 μm were used as reinforcement in this study. Cold sprayed Ni-Ni3Al samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles.

  6. AL Amyloidosis

    PubMed Central

    2012-01-01

    Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig) light chains (LC) (most commonly of lambda isotype) usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and/or immunofluorescence. Due to the

  7. Controlled environment specimen transfer.

    PubMed

    Damsgaard, Christian D; Zandbergen, Henny; W Hansen, Thomas; Chorkendorff, Ib; B Wagner, Jakob

    2014-08-01

    Specimen transfer under controlled environment conditions, such as temperature, pressure, and gas composition, is necessary to conduct successive complementary in situ characterization of materials sensitive to ambient conditions. The in situ transfer concept is introduced by linking an environmental transmission electron microscope to an in situ X-ray diffractometer through a dedicated transmission electron microscope specimen transfer holder, capable of sealing the specimen in a gaseous environment at elevated temperatures. Two catalyst material systems have been investigated; Cu/ZnO/Al2O3 catalyst for methanol synthesis and a Co/Al2O3 catalyst for Fischer-Tropsch synthesis. Both systems are sensitive to ambient atmosphere as they will oxidize after relatively short air exposure. The Cu/ZnO/Al2O3 catalyst, was reduced in the in situ X-ray diffractometer set-up, and subsequently, successfully transferred in a reactive environment to the environmental transmission electron microscope where further analysis on the local scale were conducted. The Co/Al2O3 catalyst was reduced in the environmental microscope and successfully kept reduced outside the microscope in a reactive environment. The in situ transfer holder facilitates complimentary in situ experiments of the same specimen without changing the specimen state during transfer. PMID:24824787

  8. Rolling Motions During Solar Prominence Eruptions in Asymmetric Magnetic Environments

    NASA Astrophysics Data System (ADS)

    McKillop, Sean; Miralles, Mari Paz; Murphy, Nicholas Arnold; McCauley, Patrick

    2014-06-01

    Panasenco et al. [1] report observations of several CMEs that display a rolling motion about the axis of the erupting prominence. Murphy et al. [2] present simulations of line-tied asymmetric magnetic reconnection that make a falsifiable prediction regarding the handedness of rolling motions of flux ropes during solar eruptions. We will present initial results of our work to investigate this prediction. To determine the strength and any asymmetric properties of the magnetic field in the regions of interest in the photosphere, we use magnetograms from HMI. We use AIA observations to determine if there is any rolling motion and, if so, what handedness the rolling motions have. We then compare the photospheric magnetic information with the handedness information to determine if there is any relationship between the two. Finally, we will discuss prospects for diagnosing rolling motions of erupting prominence using off-limb IRIS observations.[1] O. Panasenco, S. Martin, A. D. Joshi, & N. Srivastava, J. Atmos. Sol.-Terr. Phys., 73, 1129 (2011)[2] N. A. Murphy, M. P. Miralles, C. L. Pope, J. C. Raymond, H. D. Winter, K. K. Reeves, D. B. Seaton, A. A. van Ballegooijen, & J. Lin, ApJ, 751, 56 (2012)

  9. A high-resolution atlas of the infrared spectrum of the sun and the earth atmosphere from space. A compilation of ATMOS spectra of the region from 650 to 4800 cm-1 (2.3 to 16 μm). Vol. I. The sun.

    NASA Astrophysics Data System (ADS)

    Farmer, C. B.; Norton, R. H.

    1989-08-01

    During the period April 29 through May 2, 1985, the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment was operated as part of the Spacelab-3 payload of the Shuttle Challenger. The instrument, a modified Michelson interferometer covering the frequency range from 600 to 5000 cm-1 (2 to 16 μm) at a spectral resolution of 0.01 cm-1, recorded infrared spectra of the sun and of the earth's atmosphere at times close to entry into and exit from occultation by the earth's limb as seen from the Shuttle orbit of 360 km. Spectra were obtained that are free from absorptions due to constituents of the atmosphere (i.e., they are "pure solar" spectra).

  10. Corrosion behavior of coated 2 1/4 Cr-1 Mo and carbon steels in a simulated high p/sub S/sub 2// waste heat recovery system environment of a coal gasifier. [Al and/or Cr coatings applied by pack-diffusion process

    SciTech Connect

    Baxter, D.J.

    1986-03-01

    Corrosion tests have been conducted on coated 2-1/4Cr-1Mo and A106 carbon steels in a gaseous environment typical of that expected in a downstream waste-heat recovery system of a coal gasifier. The environment contained controlled oxygen and sulfur partial pressures, and the tests were run in a rig designed to expose specimens under simulated heat-exchanger conditions. Uncoated steel substrates exhibited breakaway corrosion behavior. Incoloy 800 also exhibited breakaway corrosion behavior. Coatings containing the stable oxide-forming elements Al and/or Cr were applied by pack-diffusion processes by several commercial vendors. Coatings containing Al contained numerous internal oxide particles and cracks while chromizing occasionally resulted in coatings containing voids. Results indicate that a minimum Cr concentration of approximately 20 to 22 wt % is required to suppress rapid corrosive degradation in the most aggressive environment used in the investigation. A minimum Al concentration could not be as closely defined, but would appear to lie in the range of 14 to 20 wt %. A minimum total concentration of combined additions of Al and Cr could not be defined. The presence of cracks in the aluminized materials promotes internal oxidation. Two Ni-base weld metals were used to simulate joining or repair operations of prior aluminized steel substrates. Both Inconel 625 and Inconel 72 exhibited breakaway corrosion behavior, the former at an unacceptable rate and the latter at a rate on the borderline of acceptability. The corrosion behavior of all coated and coated/welded materials is described and the results used to formulate a provisional specification for the procurement of coatings for eventual commercial application. 11 refs., 15 figs., 5 tabs.

  11. Suicide: Incidence or Prevalence? Comments on Hernández-Alvarado et al. Increase in Suicide Rates by Hanging in the Population of Tabasco, Mexico between 2003 and 2012. Int. J. Environ. Res. Public Health 2016, 13, 552.

    PubMed

    Fernández-Niño, Julián Alfredo

    2016-01-01

    I recently reviewed the paper published in this journal by Hernández-Alvarado et al., titled "Increase in Suicide Rates by Hanging in the Population of Tabasco, Mexico between 2003 and 2012" [1], and I noticed that the epidemiological concept "prevalence" is not correctly used.[...]. PMID:27376318

  12. Corrigendum to Aerosol impacts on California winter clouds and precipitation during CalWater 2011: local pollution versus long-range transported dust published in Atmos. Chem. Phys., 14, 81–101, 2014

    SciTech Connect

    Fan, Jiwen; Leung, Lai-Yung R.; DeMott, Paul J.; Comstock, Jennifer M.; Singh, Balwinder; Rosenfeld, Daniel; Tomlinson, Jason M.; White, A.; Prather, Kimberly; Minnis, Patrick; Ayers, J. K.; Min, Qilong

    2014-05-01

    In the paper “Aerosol impacts on California winter clouds and precipitation during CalWater 2011: local pollution versus long-range transported dust” by J. Fan et al., wrong versions of Fig. 8 and Fig. 12 were published. Please find the correct figures below.

  13. Magnetism of Al-substituted magnetite reduced from Al-hematite

    NASA Astrophysics Data System (ADS)

    Jiang, Zhaoxia; Liu, Qingsong; Zhao, Xiang; Roberts, Andrew P.; Heslop, David; Barrón, Vidal; Torrent, José

    2016-06-01

    Aluminum-substituted magnetite (Al-magnetite) reduced from Al-substituted hematite or goethite (Al-hematite or Al-goethite) is an environmentally important constituent of magnetically enhanced soils. In order to characterize the magnetic properties of Al-magnetite, two series of Al-magnetite samples were synthesized through reduction of Al-hematite by a mixed gas (80% CO2 and 20% CO) at 395°C for 72 h in a quartz tube furnace. Al-magnetite samples inherited the morphology of their parent Al-hematite samples, but only those transformed from Al-hematite synthesized at low temperature possessed surficial micropores, which originated from the release of structural water during heating. Surface micropores could thus serve as a practical fingerprint of fire or other high-temperature mineralogical alteration processes in natural environments, e.g., shear friction in seismic zones. In addition, Al substitution greatly affects the magnetic properties of Al-magnetite. For example, coercivity (Bc) increases with increasing Al content and then decreases slightly, while the saturation magnetization (Ms), Curie temperature (Tc), and Verwey transition temperature (Tv) all decrease with increasing Al content due to crystal defect formation and dilution of magnetic ions caused by Al incorporation. Moreover, different trends in the correlation between Tc and Bc can be used to discriminate titanomagnetite from Al-magnetite, which is likely to be important in environmental and paleomagnetic studies, particularly in soil.

  14. Corrigendum to "Aerosol indirect effects from shipping emissions: sensitivity studies with the global aerosol-climate model ECHAM-HAM" published in Atmos. Chem. Phys., 12, 5985-6007, 2012

    NASA Astrophysics Data System (ADS)

    Peters, K.; Stier, P.; Quaas, J.; Graßl, H.

    2013-07-01

    An error in the calculation of the emitted number of primary sulfate particles for a given mass of emitted elementary sulfur has recently been identified in HAM, i.e. the aerosol module utilised in the ECHAM-HAM aerosol climate model. Correcting for this error substantially alters the estimates of top-of-atmosphere radiative forcing due to aerosol indirect effects from global shipping emissions (year 2000) as presented in Peters et al. (2012). Here, we shortly present these new results.

  15. Erratum to "Solar Sources and Geospace Consequences of Interplanetary Magnetic Clouds Observed During Solar Cycle 23-Paper 1" [J. Atmos. Sol.-Terr. Phys. 70(2-4) (2008) 245-253

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.; Akiyama, S.; Yashiro, S.; Michalek, G.; Lepping, R. P.

    2009-01-01

    One of the figures (Fig. 4) in "Solar sources and geospace consequences of interplanetary magnetic Clouds observed during solar cycle 23 -- Paper 1" by Gopalswamy et al. (2008, JASTP, Vol. 70, Issues 2-4, February 2008, pp. 245-253) is incorrect because of a software error in t he routine that was used to make the plot. The source positions of various magnetic cloud (MC) types are therefore not plotted correctly.

  16. Petrogenesis and PGE distribution in the Al- and Cr-rich chromitites of the Qalander ophiolite, northeastern Iraq: Implications for the tectonic environment of the Iraqi Zagros Suture Zone

    NASA Astrophysics Data System (ADS)

    Ismail, Sabah A.; Kettanah, Yawooz A.; Chalabi, Sawsan N.; Ahmed, Ahmed H.; Arai, Shoji

    2014-08-01

    The Qalander ophiolite is a small, poorly preserved and incomplete mélange-type complex situated within the Eocene-Oligocene Walash-Naopurdan Group in the Iraqi Zagros Suture Zone (IZSZ). It is one of six fragmented ophiolite complexes emplaced in the IZSZ during the Cretaceous and Tertiary. Within the Qalander ophiolite, serpentinized dunite and harzburgite hosts small lens-shaped podiform high-Al (North Qalander) and high-Cr (North Shitna) chromitite bodies. The average range of Cr-, Mg-, and Fe3-numbers for North Qalander chromitites is 39-53, 75-77, and 3-5, respectively; meanwhile those for North Shitna chromitites are 78-80, 65-73, and 6-8, respectively. The ranges of Al2O3 wt.% and FeO/MgO for the North Qalander and North Shitna chromitites are 15-15.5 and 0.8-1.0, and 9.0-10.5 and 0.4-1.0, respectively. In addition to pyroxene and olivine, inclusions of laurite, millerite and galena were detected within the chromitites of Qalander ophiolite. The matrix minerals between chromite grains are serpentinized olivine and pyroxene, chlorite, and calcite; grains of magnetite, pyrite and ilmenite are also common accessories. The concentrations of platinum-group elements (PGE) in both varieties are typical for the ophiolitic chromitites, but they show two distinct patterns of PGE enrichment. The high-Cr chromitites have relatively uniform mantle-normalized PGE distribution patterns with a steep slope, positive Ru and negative Pt anomalies, and they show enrichment of PGE and depletion in Pt relative to the average upper mantle. The high-Al chromitites show relatively gently sloping patterns with slight positive Ru and negative Pt anomalies, high iridium-group PGE (IPGE) abundances relative to the high platinum-group PGE (PPGE), and are distinctly enriched in Pt and Pd relative to the upper mantle and the average abundances in the high-Cr chromitites. The differences in the PGE content, geochemistry, rare earth element (REE), mineral chemistry and petrographical

  17. Probing dusty circumstellar environments with polarimetric aperture-masking interferometry

    NASA Astrophysics Data System (ADS)

    Norris, Barnaby R. M.; Tuthill, Peter G.; Ireland, Michael J.; Lacour, Sylvestre; Zijlstra, Albert A.; Lykou, Foteini; Evans, Thomas M.; Stewart, Paul; Bedding, Timothy R.; Guyon, Olivier; Martinache, Frantz

    2012-07-01

    Aperture-masking interferometry allows diffraction-limited images to be recovered despite the turbulent atmo­ sphere. Here, this approach has been combined with polarimetry to form a novel technique allowing the dusty environments of mass-losing stars (so-called AGB stars) and proto-planetary and debris disks to be imaged, the characterisation of which is key to understanding the recycling of matter and the formation of new planetary systems. Polarimetric aperture-masking interferometry produces images by exploiting the fact that starlight scattered by circumstellar dust becomes strongly polarised. Essentially, aperture-masking allows access to the small spatial scales (rv1Omas) necessary while polarimetry allows light from the dust and star to be differentiated. Furthermore, measurements at multiple wavelengths allow dust grain sizes to be calculated using Mie scattering theory. Excellent results have already been obtained at near-IR wavelengths using the NACO instrument at the VLT. The next step is to leverage the higher spatial resolution and polarisation signal found in the visible, rather than near-IR. To this end, a new instrument allowing precision polarimetric aperture masking interferometry at 600-800nm is being developed for an 8m class telescope, details of which will also be presented.

  18. A high-resolution atlas of the infrared spectrum of the sun and the earth atmosphere from space. A compilation of ATMOS spectra of the region from 650 to 4800 cm-1 (2.3 to 16 microns). Volume 2: Stratosphere and mesosphere, 650 to 3350 cm-1

    NASA Technical Reports Server (NTRS)

    Farmer, Crofton B.; Norton, Robert H.

    1989-01-01

    During the period April 29 to May 2, 1985, the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment was operated for the first time, as part of the Spacelab-3 payload of the shuttle Challenger. The principal purpose of this experiment was to study the distributions of the atmosphere's minor and trace molecular constituents. The instrument, a modified Michelson interferometer covering the frequency range from 600 to 5000/cm-1 at a spectral resolution of 0.01/cm-1, recorded infrared absorption spectra of the sun and of the earth's atmosphere at times close to entry into and exit from occultation by the earth's limb. Spectra were obtained that are free from absorptions due to constituents of the atmosphere (i.e., they are pure solar spectra), as well as spectra of the atmosphere itself, covering line-of-sight tangent altitudes that span the range from the lower thermosphere to the bottom of the troposphere. This atlas presents a compilation of these spectra arranged in a hardcopy format suitable for quick-look reference purposes. Volume 2 covers the stratosphere and mesosphere (i.e., tangent altitudes from 20 to 80 km) for frequencies from 650 to 3350/cm-1.

  19. A high-resolution atlas of the infrared spectrum of the sun and the earth atmosphere from space. A compilation of ATMOS spectra of the region from 650 to 4800 cm-1 (2.3 to 16 microns). Volume 2: Stratosphere and mesosphere, 650 to 3350 cm-1

    NASA Astrophysics Data System (ADS)

    Farmer, Crofton B.; Norton, Robert H.

    During the period April 29 to May 2, 1985, the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment was operated for the first time, as part of the Spacelab-3 payload of the shuttle Challenger. The principal purpose of this experiment was to study the distributions of the atmosphere's minor and trace molecular constituents. The instrument, a modified Michelson interferometer covering the frequency range from 600 to 5000/cm-1 at a spectral resolution of 0.01/cm-1, recorded infrared absorption spectra of the sun and of the earth's atmosphere at times close to entry into and exit from occultation by the earth's limb. Spectra were obtained that are free from absorptions due to constituents of the atmosphere (i.e., they are pure solar spectra), as well as spectra of the atmosphere itself, covering line-of-sight tangent altitudes that span the range from the lower thermosphere to the bottom of the troposphere. This atlas presents a compilation of these spectra arranged in a hardcopy format suitable for quick-look reference purposes. Volume 2 covers the stratosphere and mesosphere (i.e., tangent altitudes from 20 to 80 km) for frequencies from 650 to 3350/cm-1.

  20. Iowa's Environment.

    ERIC Educational Resources Information Center

    Ruth, Amy, Ed.

    1994-01-01

    This theme issue explores the changes in Iowa's environment. When Native Americans lived in Iowa hundreds of years ago, the land was rich in tall grasslands, fertile soil, wildlife, wetlands, and unpolluted waters. When European-American pioneers settled Iowa in 1833, they changed the environment in order to survive. The first article in this…

  1. Aquatic Environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic microbiology can be defined as the study of microorganisms and microbial communities in water environments. Aquatic environments occupy more than 70% of the earth’s surface including oceans, estuaries, rivers, lakes, wetlands, streams, springs, and aquifers. Water is essential for life and m...

  2. Glass corrosion in natural environment

    NASA Technical Reports Server (NTRS)

    Thorpe, Arthur N.

    1989-01-01

    A series of studies of the effects of solutes which appear in natural aqueous environments, specifically Mg and Al, under controlled conditions, permit characterization of the retardation of silicate glass leaching in water containing such solutes. In the case of Mg the interaction with the glass appears to consist of exchange with alkali ions present in the glass to a depth of several microns. The effect of Al can be observed at much lower levels, indicating that the mechanism in the case of Al involves irreversible formation of aluminosilicate species at the glass surface.

  3. Low cycle fatigue of FeAl(42 at. % Al) at room temperature

    SciTech Connect

    Hanes, D.B.; Gibala, R.

    1997-12-31

    The monotonic mechanical behavior in tension and compression of FeAl has been well documented. However, very little work has been done on the cyclic deformation behavior of this material. In this work, the behavior of FeAl (42 at. % Al) under low cycle fatigue was studied, including the effects of test environments and surface coatings. It was found that the fatigue life of this alloy is limited by environmental embrittlement. This embrittlement process can be equally well prevented by deformation in an oxygen environment or by coating the alloy with a protective film. The type of film applied appears to have little effect. Similar results were seen in monotonic testing.

  4. Temporal variability in Chemical and Stable isotopic characteristics of ambient bulk aerosols over a coastal environment of India

    NASA Astrophysics Data System (ADS)

    Agnihotri, R.; Karapurkar, S. G.; Sarma, V. V.; Praveen, P.; Kumar, M. D.

    2012-12-01

    India, while local marine sources and mineral dust appear to dominate chemical composition of aerosols during pre-monsoon period. References: Agnihotri, R., Mandal, T. K., Karapurkar, S., Naja, M., Gadi, R., Ahammed, Y. N., Kumar, A., Saud, T., and Saxena, M. (2011) Stable carbon and nitrogen isotopic composition of bulk aerosols over India and Northern Indian Ocean, Atmos. Environ., 45, 2828-2835, 2011 Pavuluri, C. M., K. Kawamura, T. Swaminathan, and E. Tachibana (2011), Stable carbon isotopic compositions of total carbon, dicarboxylic acids and glyoxylic acid in the tropical Indian aerosols: Implications for sources and photochemical processing of organic aerosols, J. Geophys. Res., 116, D18307, doi:10.1029/2011JD015617 Turekian, V. C., S. A. Macko, and W. C. Keene (2003), Concentrations, isotopic compositions, and sources of size-resolved, particulate organic carbon and oxalate in near-surface marine air at Bermuda during spring, J. Geophys. Res., 108, 4157, doi:10.1029/2002JD002053

  5. Sources of SOA gaseous precursors in contrasted urban environments: a focus on mono-aromatic compounds and intermediate volatility compounds

    NASA Astrophysics Data System (ADS)

    Salameh, Therese; Borbon, Agnès; Ait-Helal, Warda; Afif, Charbel; Sauvage, Stéphane; Locoge, Nadine; Bonneau, Stéphane; Sanchez, Olivier

    2016-04-01

    , SP95 E10, and SP98) and was used to constraint evaporative emissions in order to predict the headspace vapour composition (Harley and Coulter-Burke, 2000). Modelled and observed compositions are in good agreement (differences up to 20%). Therefore, the implemented model is a relevant tool to test the sensitivity of BTEX and other VOCs ambient composition to evaporative emissions of fuels with regards to their composition. Such analysis will be extended to other target cities and similarities/differences will be presented regarding regional characteristics. This work was supported by the Ile de France region, Life and PHOTOPAQ grant, PICS-CNRS, ENVIMED and ChArMEx. We would like to thank Laurence Dépelchin and Thierry Léonardis for technical support and AIRPARIF for providing the data. Borbon, A., et al. (2013) Emission ratios of anthropogenic VOC in northern mid-latitude megacities: observations vs. emission inventories in Los Angeles and Paris, J. Geophys. Res. 118, 2041 - 2057. Harley, R. and Coulter-Burke, S. (2000) Relating Liquid Fuel and Headspace Vapor Composition for California Reformulated Gasoline Samples Containing Ethanol, Environ. Sci. Technol. 34, 4088-4094. Ait-Helal, W.; Borbon, A.; Sauvage, S.; et al., Atmos. Chem. Phys. vol. 14 , No. 19 , p. 10439-10464

  6. Characterization of Al30 in commercial poly-aluminum chlorohydrate by solid-state (27)Al NMR spectroscopy.

    PubMed

    Phillips, Brian L; Vaughn, John S; Smart, Scott; Pan, Long

    2016-08-15

    Investigation of commercially produced hydrolysis salts of aluminum by solid-state (27)Al NMR spectroscopy and size-exclusion chromatography (SEC) reveals well-defined and distinct Al environments that can be related to physicochemical properties. (27)Al MAS and MQ-MAS NMR spectroscopic data show that the local structure of the solids is dominated by moieties that closely resemble the Al30 polyoxocation (Al30O8(OH)56(H2O)26(18+)), accounting for 72-85% of the total Al. These Al30-like clusters elute as several size fractions by SEC. Comparison of the SEC and NMR results indicates that the Al30-like clusters includes intact isolated clusters, moieties of larger polymers or aggregates, and possibly fragments resembling δ-Al13 Keggin clusters. The coagulation efficacy of the solids appears to correlate best with the abundance of intact Al30-like clusters and of smaller species available to promote condensation reactions. PMID:27232539

  7. Microstructure of laser clad Ni- Cr- Al- Hf alloy on a γ' strengthened ni- base superalloy

    NASA Astrophysics Data System (ADS)

    Singh, Jogender; Mazumder, J.

    1988-08-01

    Alloys and coatings for alloys for improved high temperature service life under aggressive atmo-spheres are of great contemporary interest. There is a general consensus that the addition of rare earths such as Hf will provide many beneficial effects for such alloys. The laser cladding technique was used to produce Ni-Cr-AI-Hf alloys with extended solid solution of Hf. A 10 kW CO2 laser with mixed powder feed was used for laser cladding. Optical, scanning electron (SEM) and scanning transmission electron (STEM) microscopy were employed to characterize the microstructure of alloys produced during laser cladding processes. Microstructural studies revealed grain refinement, considerable in-crease in solubility of Hf in the matrix, Hf-rich precipitates, and new metastable phases. The size and morphology of γ' (Ni3Al) phase were discussed in relation to its microchemistry and the laser processing conditions. This paper will report the microstructural development in this laser clad Ni-Cr-AI-Hf alloy.

  8. Synthetic environments

    NASA Astrophysics Data System (ADS)

    Lukes, George E.; Cain, Joel M.

    1996-02-01

    The Advanced Distributed Simulation (ADS) Synthetic Environments Program seeks to create robust virtual worlds from operational terrain and environmental data sources of sufficient fidelity and currency to interact with the real world. While some applications can be met by direct exploitation of standard digital terrain data, more demanding applications -- particularly those support operations 'close to the ground' -- are well-served by emerging capabilities for 'value-adding' by the user working with controlled imagery. For users to rigorously refine and exploit controlled imagery within functionally different workstations they must have a shared framework to allow interoperability within and between these environments in terms of passing image and object coordinates and other information using a variety of validated sensor models. The Synthetic Environments Program is now being expanded to address rapid construction of virtual worlds with research initiatives in digital mapping, softcopy workstations, and cartographic image understanding. The Synthetic Environments Program is also participating in a joint initiative for a sensor model applications programer's interface (API) to ensure that a common controlled imagery exploitation framework is available to all researchers, developers and users. This presentation provides an introduction to ADS and the associated requirements for synthetic environments to support synthetic theaters of war. It provides a technical rationale for exploring applications of image understanding technology to automated cartography in support of ADS and related programs benefitting from automated analysis of mapping, earth resources and reconnaissance imagery. And it provides an overview and status of the joint initiative for a sensor model API.

  9. New Particle Formation Events During 2013 in Hada Al Sham, Saudi-Arabia

    NASA Astrophysics Data System (ADS)

    Neitola, K.; Hyvärinen, A.; Lihavainen, H.; Alghamdi, M.; Hussein, T.; Khodeir, M.; Shehata, A.; Laaksonen, A. J.; Kulmala, M. T.

    2014-12-01

    clear growth, S is clear shrinkage, G + S is both growth and shrinkage and unclear is not clear in either way.ReferencesM. Dal Maso, et al. (2005). Bor. Env. Res., 10, 323-336.M. Kulmala, et al. (2006). Atmos. Chem. Phys., 6, 787-793. M. Kulmala, et al. (2013). Science, 336, 943-946.

  10. Preservation Environments

    NASA Technical Reports Server (NTRS)

    Moore, Reagan W.

    2004-01-01

    The long-term preservation of digital entities requires mechanisms to manage the authenticity of massive data collections that are written to archival storage systems. Preservation environments impose authenticity constraints and manage the evolution of the storage system technology by building infrastructure independent solutions. This seeming paradox, the need for large archives, while avoiding dependence upon vendor specific solutions, is resolved through use of data grid technology. Data grids provide the storage repository abstractions that make it possible to migrate collections between vendor specific products, while ensuring the authenticity of the archived data. Data grids provide the software infrastructure that interfaces vendor-specific storage archives to preservation environments.

  11. Thermal Environments.

    ERIC Educational Resources Information Center

    Rutgers, Norman

    The role that a good thermal environment plays in the educational process is discussed. Design implications arise from an analysis of the heating and ventilating principles as apply to vocational-technical facilities. The importance of integrating thermal components in the total design is emphasized. (JS)

  12. Outdoor Environments

    ERIC Educational Resources Information Center

    Tomascoff, Rocky

    2009-01-01

    In this article, the author describes an art project in which students create their own outdoor environments using a tri-wall frame--a triple-layered cardboard, which is very lightweight and strong. Then the students compose a few sentences describing the scene or place.

  13. Library Environment.

    ERIC Educational Resources Information Center

    Computers in Libraries, 1993

    1993-01-01

    This special section includes two articles that review products and services for the automated library environment. Highlights include ergonomic products; products for visually, hearing-, and speech-impaired users; analog film recorders; computer filters; document imaging systems; electric filing systems; and printers. A list of vendors is…

  14. Architecture & Environment

    ERIC Educational Resources Information Center

    Erickson, Mary; Delahunt, Michael

    2010-01-01

    Most art teachers would agree that architecture is an important form of visual art, but they do not always include it in their curriculums. In this article, the authors share core ideas from "Architecture and Environment," a teaching resource that they developed out of a long-term interest in teaching architecture and their fascination with the…

  15. Alexandria (Al Iskandariya), Egypt

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of Alexandria was taken by astronauts on board the International Space Station in December 2000 using an Electronic Still Camera. A wider-angle view (STS088-739-90) taken from the Space Shuttle in December 1998 is available for context. Alexandria (Al Iskandariya) occupies a T-shaped peninsula and strip of land separating the Mediterranean from Lake Mariout. Originally the town was built upon a mole (stone breakwater) called Heptastadium, which joined the island of Pharos (see referenced website, below) to the mainland. Since then sedimentary deposits have widened the mole. Since 1905, when the 370,000 Alexandrians lived in an area of about 4 sq km between the two harbors, the city (population 4 million; see referenced website, below) has grown beyond its medieval walls and now occupies an area of about 300 sq km. The Mahmudiya Canal, connecting Alexandria with the Nile, runs to the south of the city and, by a series of locks, enters the harbor of the principal port of Egypt (note ships). The reddish and ochre polygons west of Lake Mariout are salt-evaporation, chemical-storage, and water-treatment ponds within the coastal lagoon. Reference Youssef Halim and Fatma Abou Shouk, 2000, Human impacts on Alexandria's marine environment: UNESCO, Coastal Regions and Small Islands Unit (CSI), Coastal Management Sourcebooks 2 (accessed December 20, 2000) Additional photographs taken by astronauts can be viewed at NASA-JSC's Gateway to Astronaut Photography of Earth. Image ISS001-ESC-5025 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  16. ALS - The cost cutter

    NASA Astrophysics Data System (ADS)

    Colucci, Frank

    1987-10-01

    The Advanced Launch System (ALS) development program will avail itself of existing technologies in the short term in order to produce an interim 'core' vehicle that may be operational by 1993; the full, booster-incorporating system objective will then be achieved in 1998. This programmatic 'decoupling' of booster and core vehicle development efforts will separate their funding peaks. The ALS program will cut costs by colocating manufacturing and launch facilities, using Al-Li alloys in booster primary structures, and aggressively applying 'paperless' CIM. The ALS launch vehicle configuration will be primarily determined by both payload requirements and flight frequency.

  17. Al-Anon/Alateen

    MedlinePlus

    Find an Al-Anon meeting Español | Français 2018 Int'l Convention Home About Group Meetings What If I'm not ready ... a meeting? What can I expect at an Al-Anon meeting? What was my first meeting like? ...

  18. Preface for Atmos. Env. Special issue on IBBI

    NASA Astrophysics Data System (ADS)

    Kaiser, Johannes W.; Keywood, Melita

    2015-11-01

    The first vegetation fires, or biomass burning, occurred shortly after the emergence of land vegetation around 400 million years ago. Biomass burning is now an integral part of many natural and human-influenced ecosystems with fires being widespread on all continents except Antarctica. They are ignited both naturally (lightning, volcanoes) and by human activities. Their subsequent spread is influenced by various factors including climate, meteorology, and the state of the vegetation as well as human activities including agricultural and suppression practises. Smoke from biomass burning constitutes a major source of trace gases and aerosols that effect atmospheric chemistry, radiative processes and cloud formation, influencing climate, human health and security. Advances in the space-based observation of open vegetation fires have lead to great innovation in quantifying fire emissions over the last 15 years as new sensors and retrieval techniques open new opportunities to derive more accurate information on fire occurrence, behaviour, severity and impacts. In addition a number of satellite-based observation capabilities of the atmospheric composition of smoke plumes have been implemented while fire and atmospheric modelling capabilities have greatly improved and cover scales from chemical reactions to global long-range transport. Operational forecasting systems based on the observation and models now provide real time guidance to emergency, environmental and health services related to fire spread and air quality. Furthermore, climate models include more detailed vegetation models and their interactions with fire regimes. Nevertheless, large uncertainties in the quantification of fire properties and emissions remain.

  19. Encapsulated environment.

    PubMed

    McLellan, Tom M; Daanen, Hein A M; Cheung, Stephen S

    2013-07-01

    In many occupational settings, clothing must be worn to protect individuals from hazards in their work environment. However, personal protective clothing (PPC) restricts heat exchange with the environment due to high thermal resistance and low water vapor permeability. As a consequence, individuals who wear PPC often work in uncompensable heat stress conditions where body heat storage continues to rise and the risk of heat injury is greatly enhanced. Tolerance time while wearing PPC is influenced by three factors: (i) initial core temperature (Tc), affected by heat acclimation, precooling, hydration, aerobic fitness, circadian rhythm, and menstrual cycle (ii) Tc tolerated at exhaustion, influenced by state of encapsulation, hydration, and aerobic fitness; and (iii) the rate of increase in Tc from beginning to end of the heat-stress exposure, which is dependent on the clothing characteristics, thermal environment, work rate, and individual factors like body composition and economy of movement. Methods to reduce heat strain in PPC include increasing clothing permeability for air, adjusting pacing strategy, including work/rest schedules, physical training, and cooling interventions, although the additional weight and bulk of some personal cooling systems offset their intended advantage. Individuals with low body fatness who perform regular aerobic exercise have tolerance times in PPC that exceed those of their sedentary counterparts by as much as 100% due to lower resting Tc, the higher Tc tolerated at exhaustion and a slower increase in Tc during exercise. However, questions remain about the importance of activity levels, exercise intensity, cold water ingestion, and plasma volume expansion for thermotolerance. PMID:23897690

  20. In situ microscopy of rapidly heated nano-Al and nano-Al/WO3 thermites

    NASA Astrophysics Data System (ADS)

    Sullivan, Kyle T.; Chiou, Wen-An; Fiore, Richard; Zachariah, Michael R.

    2010-09-01

    The initiation and reaction mechanism of nano-Al and nano-Al thermites in rapid heating environments is investigated in this work. A semiconductor-based grid/stage was used, capable of in situ heating of a sample from room temperature to 1473 K, and at a rate of 106 K/s, inside an electron microscope. Nano-Al was rapidly heated in a transmission electron microscope, and before and after images indicate that the aluminum migrates through the shell, consistent with a diffusion-based mechanism. A nano-Al/WO3 composite was then heated in a scanning electron microscope. The results indicate that a reactive sintering mechanism is occurring for the nano-Al/WO3 thermite, as the products are found to be in surface contact and significantly deformed after the heating pulse.

  1. 26Al+p elastic and inelastic scattering reactions and galactic abundances of 26Al

    NASA Astrophysics Data System (ADS)

    Pittman, S. T.; Bardayan, D. W.; Chae, K. Y.; Chipps, K. A.; Jones, K. L.; Kozub, R. L.; Matei, C.; Matos, M.; Moazen, B. H.; Nesaraja, C. D.; O'Malley, P. D.; Pain, S. D.; Parker, P. D.; Peters, W. A.; Shriner, J. F., Jr.; Smith, M. S.

    2012-06-01

    Galactic 26Al is the first radioactive nucleus to be positively identified by γ-ray astronomy with detection of the 1.809 MeV γ ray associated with its decay. This nucleus is destroyed in astrophysical environments in the 26Al(p,γ)27Si and inelastic 26Al+p scattering reactions where properties of 27Si levels determine reaction rates. To investigate these properties, elastic and inelastic 26Al+p scattering reactions were measured between Ec.m. = 0.5-1.5 MeV at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL). A candidate for a new resonance in the 26Al(p,γ)27Si reaction was identified. Upper limits were also set on the strengths of postulated resonances and on the cross section of the inelastic reaction, but there is little effect on current reaction rate calculations.

  2. Mexican environments

    SciTech Connect

    Babcock, L.; Nieder, P.

    1995-06-01

    This paper addresses the broad Mexican demographic/economic environment as it influences/interacts with the Mexican physical environment. Mexico is relatively resource-rich, but a high population yields a low per capita income, one sixth that of the United States an Canada, still above levels of most other American countries. The Mexican population has become highly urbanized, and population will continue to increase well into the next century. Mexico City will continue to dominate the Mexican urban hierarchy into the future, and the heavy concentration of people has resulted in a heavy concentration of environmental problems in the Mexico City region. A multi-billion-dollar program has been implemented with a goal of limiting air emissions in 2010 to the levels experienced in 1990. Numerous Mexican environmental problems exist beyond Mexico City, in border areas, and throughout Mexico, but qualified professionals and other resources needed for assessments and management are lacking. The authors conclude that continued economic/environmental cooperation among Canada, the United States, and Mexico will help Mexico to acquire resources needed to improve its infrastructure, environmental education, and environmental education, and environmental management, but the authors question whether Mexico, even with reduced population growth, will be able to attain levels of affluence currently enjoyed in the United State and Canada. They raise, but leave unanswered, the larger question of the level of environmentally sound development which is achievable, appropriate, and sustainable for Mexico and for the North American continent as a whole.

  3. Fetal environment

    PubMed Central

    Kinare, Arun

    2008-01-01

    The intrauterine environment has a strong influence on pregnancy outcome. The placenta and the umbilical cord together form the main supply line of the fetus. Amniotic fluid also serves important functions. These three main components decide whether there will be an uneventful pregnancy and the successful birth of a healthy baby. An insult to the intrauterine environment has an impact on the programming of the fetus, which can become evident in later life, mainly in the form of cardiovascular diseases, diabetes, and certain learning disabilities. The past two decades have witnessed major contributions from researchers in this field, who have included ultrasonologists, epidemiologists, neonatologists, and pediatricians. Besides being responsible for these delayed postnatal effects, abnormalities of the placenta, umbilical cord, and amniotic fluid also have associations with structural and chromosomal disorders. Population and race also influence pregnancy outcomes to some extent in certain situations. USG is the most sensitive imaging tool currently available for evaluation of these factors and can offer considerable information in this area. This article aims at reviewing the USG-related developments in this area and the anatomy, physiology, and various pathologies of the placenta, umbilical cord, and the amniotic fluid. PMID:19774194

  4. [Environmental factors in ALS].

    PubMed

    Juntas-Morales, Raul; Pageot, Nicolas; Corcia, Philippe; Camu, William

    2014-05-01

    ALS is likely to be a disorder of multifactorial origin. Among all the factors that may increase the risk of ALS, environmental ones are being studied for many years, but in the recent years, several advances have pointed to a new interest in their potential involvement in the disease process, especially for the cyanotoxin BMAA. Food containing BMAA has been found on Guam, a well-known focus of ALS/parkinsonism/dementia and high levels of BMAA have been identified into the brain of these patients. The BMAA cyanotoxin is potentially ubiquitous and have also been found into the food of patients who died from ALS both in Europe and USA. BMAA can be wrongly integrated into the protein structure during mRNA traduction, competing with serine. This may induce abnormal protein folding and a subsequent cell death. Heavy metals, such as lead or mercury may be directly toxic for neuronal cells. Several works have suggested an increased risk of ALS in individuals chronically exposed to these metals. Exposure to pesticides has been suggested to be linked to an increased risk of developing ALS. The mechanism of their toxicity is likely to be mediated by paraoxonases. These proteins are in charge of detoxifying the organism from toxins, and particularly organophosphates. To date, there are insufficient scientific data to suggest that exposure to electromagnetic fields may increase the risk of having ALS. We are particularly missing longitudinal cohorts to demonstrate that risk. PMID:24703731

  5. Environment matters

    SciTech Connect

    2005-07-01

    This year's annual review is devoted to the theme of environmental health. It contains: an overview by the Director of the World Bank's Environment Department, J. Warren Evans; viewpoints on health risks of environmental pollution, integrating health concerns into carbon planning, sanitation in the world's poorest countries and impacts of indoor air pollution on health; and reviews on the World Bank's efforts to adapt safeguards to demanding priorities and on the Banks' 2005 environmental portfolio. Feature articles include a review of the Bank's Clean Air Initiative (now active in Africa, South and East Asia and Latin America). Reviews of work in the Bank's six regions focus on efforts to address the linkages among poverty, environmental pollution and human health.

  6. All About ALS

    MedlinePlus

    ... External link, please review our exit disclaimer . Subscribe All About ALS Understanding a Devastating Disorder In the ... a coffee pot, or button a shirt. Eventually, all muscles under voluntary control are affected, and people ...

  7. Amyotrophic Lateral Sclerosis (ALS)

    MedlinePlus

    ... Pictures of ALS Mutant Proteins Support Two Major Theories About How the Disease is Caused May 2003 ... All NINDS-prepared information is in the public domain and may be freely copied. Credit to the ...

  8. Genetic Testing for ALS

    MedlinePlus

    ... Involved Donate Familial Amyotrophic Lateral Sclerosis (FALS) and Genetic Testing By Deborah Hartzfeld, MS, CGC, Certified Genetic ... guarantee a person will develop symptoms of ALS. Genetic Counseling If there is more than one person ...

  9. ALS synchrotron radiation shielding

    SciTech Connect

    Donahue, R.J.

    1995-10-01

    This note discusses the assumptions and results of synchrotron radiation shielding estimates for ALS bend magnet and wiggler beamlines. Estimates of gas bremsstrahlung production are not included and are dealt with elsewhere.

  10. What Is ALS?

    MedlinePlus

    ... scarring or hardening ("sclerosis") in the region. Motor neurons reach from the brain to the spinal cord ... the body. The progressive degeneration of the motor neurons in ALS eventually leads to their demise. When ...

  11. Modern carbonate environments

    SciTech Connect

    Bhattacharyya, A.; Friedman, G.M.

    1983-01-01

    This book offers help in evaluating potential sites for oil and gas accumulations. Pointing the way to discovery of hydrocarbons in carbonate reservoirs, this volume discusses modern carbonate depositional environments in different geomorphic settings. It compiles papers by scientists whose observations have revolutionized current thinking on facies relationships in ancient carbonate rock. Contents include: Selected carbonate regions --The Algal Sediments on Androa Island in the Bahamas, Sedimentary Facies, Interaction of Genetic Processes in Holocene Reefs off North Eleuthera Island in the Bahamas, Recent Anhydrite, Holocene Shallow-Water Carbonate and Evaporite Sediments of Khor al Bazam; Carbonate production--On the Origin of Aragonite in the Dead Sea, Carbonate Production by Coral Reefs; Cold-water carbonates--Contributions on the Geology of the Northwestern Peninsula of Iceland, Evaluation of Cold-Water Carbonates as a Possible Paleoclimatic Indicator.

  12. MCrAlY bond coat with enhanced Yttrium layer

    DOEpatents

    Jablonski, Paul D; Hawk, Jeffrey A

    2015-04-21

    One or more embodiments relates to an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y--Al.sub.2O.sub.3 layer. The MCrAlY layer is comprised of a .gamma.-M solid solution, a .beta.-MAl intermetallic phase, and Y-type intermetallics. The Y--Al.sub.2O.sub.3 layer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the Al.sub.2O.sub.3 lattice. Both the MCrAlY layer and the Y--Al.sub.2O.sub.3 layer have a substantial absence of Y--Al oxides, providing advantage in the maintainability of the Yttrium reservoir within the MCrAlY bulk. The MCrAlY bond coat may be fabricated through application of a Y.sub.2O.sub.3 paste to an MCrAlY material, followed by heating in a non-oxidizing environment.

  13. FeAl and NbAl3 Intermetallic-HVOF Coatings: Structure and Properties

    NASA Astrophysics Data System (ADS)

    Guilemany, J. M.; Cinca, N.; Dosta, S.; Cano, I. G.

    2009-12-01

    Transition metal aluminides in their coating form are currently being explored in terms of resistance to oxidation and mechanical behavior. This interest in transition metal aluminides is mainly due to the fact that their high Al content makes them attractive for high-temperature applications. This is also a reason to study their resistance to wear; they may be suitable for use in applications that produce a lot of wear in aggressive environments, thus replacing established coating materials. In this study, the microstructure, microhardness, and wear and oxidation performance of FeAl and NbAl3 coatings produced by high-velocity oxy-fuel spraying are evaluated with two main aims: (i) to compare these two coating systems—a commonly studied aluminide (FeAl) and, NbAl3, an aluminide whose deposition by thermal spraying has not been attempted to date—and (ii) to analyze the relationship between their microstructure, composition and properties, and so clarify their wear and oxidation mechanisms. In the present study, the higher hardness of niobium aluminide coatings did not correlate with a higher wear resistance and, finally, although pesting phenomena (disintegration in oxidizing environments) were already known of in bulk niobium aluminides, here their behavior in the coating form is examined. It was shown that such accelerated oxidation was inevitable with respect to the better resistance of FeAl, but further improvements are foreseen by addition of alloying elements in that alloy.

  14. Investigation of locally favored structures in Al-La-Ni metallic glasses using ^27Al NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sandor, Magdalena; Xi, Xuekui; Wu, Yue

    2008-10-01

    Al-TM-RE (TM= transition metal, RE = rare earth) bulk metallic glasses (BMGs) with high Al content have gained much research interest due to their high potential as structural and functional materials. The first recent fabrication of La85-xAlxNi15 (15 <= x <= 70) BMGs have inspired an NMR systematic study of their locally favored structures (LFSs). These BMGs are reported to show characteristics of high thermal stability, fragility, and considerable mechanical strength. ^27Al NMR spectroscopy and nutation experiments are performed to unveil the sensitive structural dependence on line width and quadrupolar frequency with Al composition. It is observed that maximum glass forming ability (GFA) for this system prefers a decrease of symmetry at Al sites. Minimal GFA corresponding to instances of high symmetry occur in Al-rich and Al-poor regimes. These results, in addition to previous work, suggest that Ni and La atoms have unique local chemical and topological environments at different Al compositions. The monotonic decrease of relatively small ^27Al Knight shifts with increasing Al concentration demonstrates the evolution of local electronic structure at Al sites. This study is valuable in correlating the unique role that TM and RE elements play in local compositional and geometrical order of high glass-forming Al-based BMGs.

  15. Rapidly solidified NiAl and FeAl

    NASA Technical Reports Server (NTRS)

    Gaydosh, D. J.; Crimp, M. A.

    1984-01-01

    Melt spinning was used to produce rapidly solidified ribbons of the B2 intermetallics NiAl and FeAl. Both Fe-40Al and Fe-45Al possessed some bend ductility in the as spun condition. The bend ductility of Fe-40Al, Fe-45Al, and equiatomic NiAl increased with subsequent heat treatment. Heat treatment at approximately 0.85 T (sub m) resulted in significant grain growth in equiatomic FeAl and in all the NiAl compositions. Low bend ductility in both FeAl and NiAl generally coincided with intergranular failure, while increased bend ductility was characterized by increasing amounts of transgranular cleavage fracture.

  16. Superconducting Resonators with Parasitic Electromagnetic Environments

    NASA Astrophysics Data System (ADS)

    Hornibrook, John; Mitchell, Emma; Reilly, David

    2012-02-01

    Microwave losses in niobium superconducting resonators are investigated at milli-Kelvin temperatures and with low drive power. In addition to the well-known suppression of Q-factor that arises from coupling between the resonator and two-level defects in the dielectric substrate [1-4], we report strong dependence of the loaded Q-factor and resonance line-shape on the electromagnetic environment. Methods to suppress parasitic coupling between the resonator and its environment are demonstrated.[4pt] [1] Day, P.K. et al., Nature 425, 817-821 (2003).[0pt] [2] Wallraff, A. et. al., Nature 451, 162-167 (2004).[0pt] [3] Macha, P. et. al., Appl. Phys. Lett., 96, 062503 (2010).[0pt] [4] O'Connell, A.D. et. al., Appl. Phys. Lett., 92, 112903 (2008).

  17. Modulus measurements in ordered Co-Al, Fe-Al, and Ni-Al alloys

    NASA Technical Reports Server (NTRS)

    Harmouche, M. R.; Wolfenden, A.

    1985-01-01

    The composition and/or temperature dependence of the dynamic Young's modulus for the ordered B2 Co-Al, Fe-Al, and Ni-Al aluminides has been investigated using the piezoelectric ultrasonic composite oscillator technique (PUCOT). The modulus has been measured in the composition interval 48.49 to 52.58 at. pct Co, 50.87 to 60.2 at. pct Fe, and 49.22 to 55.95 at. pct Ni for Co-Al, Fe-Al, and Ni-Al, respectively. The measured values for Co-Al are in the temperature interval 300 to 1300 K, while those for the other systems are for ambient temperature only. The data points show that Co-Al is stiffer than Fe-Al, which is stiffer than Ni-Al. The data points for Fe-Al and Ni-Al are slightly higher than those reported in the literature.

  18. An interactive environment for the analysis of large Earth observation and model data sets

    NASA Technical Reports Server (NTRS)

    Bowman, Kenneth P.; Walsh, John E.; Wilhelmson, Robert B.

    1994-01-01

    Envision is an interactive environment that provides researchers in the earth sciences convenient ways to manage, browse, and visualize large observed or model data sets. Its main features are support for the netCDF and HDF file formats, an easy to use X/Motif user interface, a client-server configuration, and portability to many UNIX workstations. The Envision package also provides new ways to view and change metadata in a set of data files. It permits a scientist to conveniently and efficiently manage large data sets consisting of many data files. It also provides links to popular visualization tools so that data can be quickly browsed. Envision is a public domain package, freely available to the scientific community. Envision software (binaries and source code) and documentation can be obtained from either of these servers: ftp://vista.atmos.uiuc.edu/pub/envision/ and ftp://csrp.tamu.edu/pub/envision/. Detailed descriptions of Envision capabilities and operations can be found in the User's Guide and Reference Manuals distributed with Envision software.

  19. Al Shanker Remembers.

    ERIC Educational Resources Information Center

    American Educator, 2000

    2000-01-01

    In a 1996 interview shortly before his death, Al Shanker, longtime president of the American Federation of Teachers, discussed such topics as: his own educational experiences; how he learned about political fighting in the Boy Scouts; the appeal of socialism; multinational corporations and the nation state; teaching tough students; and John Dewey…

  20. ALS renewal moves forward

    NASA Astrophysics Data System (ADS)

    Falcone, R. W.; Feinberg, B.; Hussain, Z.; Kirz, J.; Krebs, G. F.; Padmore, H. A.; Robin, D. S.; Robinson, A. L.

    2007-11-01

    As the result of an extensive long-term planning process involving all its stakeholders—management, staff, and users—the ALS has seen its future and is aggressively moving ahead to implement its vision for keeping the facility at the cutting edge for the next 2-3 decades. The evolving strategic plan now in place aims to renew the ALS so it can address a new generation of fundamental questions about size dependent and dimensional-confinement phenomena at the nanoscale; correlation and complexity in physical, biological, and environmental systems; and temporal evolution, assembly, dynamics and ultrafast phenomena. The renewal spans three areas: (1) increased staffing at beamlines to support the growing user community and safety professionals to keep an increasingly complex facility hazard free; (2) implementing advances in accelerator, insertion device, beamline, and detector technology that will make it possible for ALS users to address emerging grand scientific and technological challenges with incisive world-class tools; and (3) construction of a user support building and guest housing that will increase the safety and user friendliness of the ALS by providing users office, meeting, experiment staging, and laboratory space for their work and on-site accommodations at reasonable rates.

  1. Fosetyl-al

    Integrated Risk Information System (IRIS)

    Fosetyl - al ; CASRN 39148 - 24 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  2. Changing polar environments: Interdisciplinary challenges

    NASA Astrophysics Data System (ADS)

    Shepson, Paul B.; Ariya, Parisa A.; Deal, Clara J.; Donaldson, D. James; Douglas, Thomas A.; Loose, Brice; Maksym, Ted; Matrai, Patricia A.; Russell, Lynn M.; Saenz, Benjamin; Stefels, Jacqueline; Steiner, Nadja

    2012-03-01

    In the past few decades, there has been enormous growth in scientific studies of physical, chemical, and biological interactions among reservoirs in polar regions. This has come, in part, as a result of a few significant discoveries: There is dramatic halogen chemistry that occurs on and above the sea ice in the springtime that destroys lower tropospheric ozone and mercury [Simpson et al., 2007; Steffen et al., 2008], the sunlit snowpack is very photochemically active [Grannas et al., 2007], biology as a source of organic compounds plays a pivotal role in these processes, and these processes are occurring in the context of rapidly changing polar regions under climate feedbacks that are as of yet not fully understood [Serreze and Barry, 2011]. Stimulated by the opportunities of the International Polar Year (IPY, 2007-2009), a number of large-scale field studies in both polar environments have been undertaken, aimed at the study of the complex biotic and abiotic processes occurring in all phases (see Figure 1). Sea ice plays a critical role in polar environments: It is a highly reflective surface that interacts with radiation; it provides a habitat for mammals and micro-organisms alike, thus playing a key role in polar trophic processes and elemental cycles; and it creates a saline environment for chemical processes that facilitate release of halogenated gases that contribute to the atmosphere's ability to photochemically cleanse itself in an otherwise low-radiation environment. Ocean-air and sea ice-air interfaces also produce aerosol particles that provide cloud condensation nuclei.

  3. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting...

  4. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting...

  5. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting...

  6. Lunar radiation environment

    NASA Astrophysics Data System (ADS)

    Schwadron, Nathan; Spence, Harlan; Wilson, Jody

    One of the goals of the CRaTER investigation is to characterize the radiation environment near the Moon in order to enable exploration. The state-of-the-art understanding developed thus far during the LRO mission is documented in a special issue of the Spaceweather Journal entitled “Space Weather: Building the observational foundation to deduce biological effects of space radiation” (Schwadron et al., 2013a). This recently published CRaTER work probes deeper into the physics of the radiation environment at the Moon. It motivates and provides the scientific basis for new investigations in the next phase of the LRO mission. The effects of Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs) range from chemical modification of the regolith, the generation of a radiation albedo that is increasingly illuminating chemical properties of the regolith, causing charging of the regolith and hazards to human explorers and robotic missions. Low-lunar orbit provides a platform for measuring SEP anisotropy over timescales of 2 hours both parallel and perpendicular to the ecliptic plane, and so far we have observed more than 18 SEP events with time-variable anisotropies during the LRO mission. Albedo proton maps of the Moon from CRaTER indicate that the flux of lunar albedo protons is correlated with elemental abundances at the lunar surface. The yield of albedo protons from the maria is 1% higher than the yield from the highlands, and there are localized peaks with even higher contrast (that may be co-located with peaks in trace elemental abundances as measured by the Lunar Prospector Gamma Ray Spectrometer). The Moon’s radiation environment both charges and affects the chemistry in the Moon’s polar regions, particularly in PSRs. This makes these regions a prime target for new CRaTER observations, since CRaTER measures GCRs and SEPs that penetrate the regolith down to 10s of cm. Thus, we review emerging discoveries from LRO/CRaTER’s remarkable exploration of

  7. ALS Project Management Manual

    SciTech Connect

    Krupnick, Jim; Harkins, Joe

    2000-05-01

    This manual has been prepared to help establish a consistent baseline of management practices across all ALS projects. It describes the initial process of planning a project, with a specific focus on the production of a formal project plan. We feel that the primary weakness in ALS project management efforts to date stems from a failure to appreciate the importance of ''up-front'' project planning. In this document, we present a guide (with examples) to preparing the documents necessary to properly plan, monitor, and control a project's activities. While following the manual will certainly not guarantee good project management, failure to address the issues we raise will dramatically reduce the chance of success. Here we define success as meeting the technical goals on schedule and within the prescribed budget.

  8. ALS insertion devices

    SciTech Connect

    Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W.V.; Humphries, D.; Kincaid, B.; Lancaster, H.; Plate, D.

    1990-11-01

    The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system. 18 refs., 9 figs., 5 tabs.

  9. Ausbildung als zentrale Aufgabe

    NASA Astrophysics Data System (ADS)

    Krämer, Walter; Schmerbach, Sibylle

    Anders als Lesen und Schreiben zählen Grundkenntnisse in Statistik heute noch nicht zu den Voraussetzungen einer sinnvollen Teilhabe am Sozialgeschehen. Und auch in der akademischen Statistik-Ausbildung gibt es noch einiges zu tun. Das vorliegende Kapitel zeichnet die Geschichte dieser akademischen Ausbildung an deutschen Universitäten nach dem zweiten Weltkrieg nach, stellt aktuelle Defizite vor und weist auf mögliche Verbesserungen hin.

  10. Opportunity's 'Rub al Khali' Panorama

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Opportunity's 'Rub al Khali' Panorama (QTVR)

    This panoramic image, dubbed 'Rub al Khali,' was acquired by NASA's Mars Exploration Rover Opportunity on the plains of Meridiani during the period from the rover's 456th to 464th sols on Mars (May 6 to May 14, 2005). Opportunity was about 2 kilometers (1.2 miles) south of 'Endurance Crater' at a place known informally as 'Purgatory Dune.'

    The rover was stuck in the dune's deep fine sand for more than a month. 'Rub al Khali' (Arabic translation: 'the empty quarter') was chosen as the name for this panorama because it is the name of a similarly barren, desolate part of the Saudi Arabian desert on Earth.

    The view spans 360 degrees. It consists of images obtained in 97 individual pointings of the panoramic camera. The camera took images with five camera filters at each pointing. This 22,780-by-6,000-pixel mosaic is an approximately true-color rendering generated using the images acquired through filters admitting light wavelengths of 750, 530, and 480 nanometers.

    Lighting varied during the nine sols it took to acquire this panorama, resulting in some small image seams within the mosaic. These seams have been smoothed in sky parts of the mosaic to better simulate the vista that a person would see if able to view it all at the same time on Mars.

    Opportunity's tracks leading back to the north (center of the panorama) are a reminder of the rover's long trek from Endurance Crater. The deep ruts dug by Opportunity's wheels as it became stuck in the sand appear in the foreground. The crest and trough of the last ripple the rover crossed before getting stuck is visible in the center. These wind-formed sand features are only about 10 to 15 centimeters (4 to 6 inches) tall. The crest of the actual ripple where the rover got stuck can be seen just to the right of center. The tracks and a few other places on and near ripple crests can

  11. Optical gain characteristics in Al-rich AlGaN/AlN quantum wells

    SciTech Connect

    Oto, Takao; Banal, Ryan G.; Funato, Mitsuru; Kawakami, Yoichi

    2014-05-05

    The optical gain characteristics of Al-rich AlGaN/AlN quantum wells (QWs) were assessed by the variable stripe length method at room temperature. An Al{sub 0.79}Ga{sub 0.21}N/AlN QW with a well width of 5 nm had a large optical gain of 140 cm{sup −1}. Increasing the excitation length induced a redshift due to the gain consumption and the consequent saturation of the amplified spontaneous emission. Moreover, a change in the dominant gain polarization with Al composition, which was attributed to switching of the valence band ordering of strained AlGaN/AlN QWs at Al compositions of ∼0.8, was experimentally demonstrated.

  12. Local formation of a Heusler structure in CoFe-Al alloys

    NASA Astrophysics Data System (ADS)

    Wurmehl, S.; Jacobs, P. J.; Kohlhepp, J. T.; Swagten, H. J. M.; Koopmans, B.; Maat, S.; Carey, M. J.; Childress, J. R.

    2011-01-01

    We systematically study the changes in the local atomic environments of Co in CoFe-Al alloys as a function of Al content by means of nuclear magnetic resonance. We find that a Co2FeAl Heusler type structure is formed on a local scale. The observed formation of a highly spin-polarized Heusler compound may explain the improved magnetotransport properties in CoFe-Al based current-perpendicular-to-the-plane spin-valves.

  13. Observations of Al, Fe and Ca(+) in Mercury's Exosphere

    NASA Technical Reports Server (NTRS)

    Bida, Thomas A.; Killen, Rosemary M.

    2011-01-01

    We report 5-(sigma) tangent column detections of Al and Fe, and strict 3-(sigma) tangent column upper limits for Ca(+) in Mercury's exosphere obtained using the HIRES spectrometer on the Keck I telescope. These are the first direct detections of Al and Fe in Mercury's exosphere. Our Ca(-) observation is consistent with that reported by The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft.

  14. Human Environment Conference: The Rush for Influence

    ERIC Educational Resources Information Center

    Bazell, Robert J.

    1971-01-01

    Describes the maneuvering to offer advice" to the planners of the United Nations Conference on the Human Environment by nongovernment organizations, including the International Congress of Scientific Unions, the International Union for the Conservation of Nature, and the Scientists' Institute for Public Information. (AL)

  15. AL Amyloidosis and Agent Orange

    MedlinePlus

    ... for survivors' benefits . Research on AL amyloidosis and herbicides The Health and Medicine Division (formally known as ... to the compounds of interest found in the herbicide Agent Orange and AL amyloidosis." VA made a ...

  16. Al(+)-ligand binding energies

    NASA Technical Reports Server (NTRS)

    Sodupe, M.; Bauschlicher, Charles W., Jr.

    1991-01-01

    Ab initio calculations are used to optimize the structure and determine the binding energies of Al(+) to a series of ligands. For Al(+)-CN, the bonding was found to have a large covalent component. For the remaining ligands, the bonding is shown to be electrostatic in origin. The results obtained for Al(+) are compared with those previously reported for Mg(+).

  17. Al Jazirah, Sudan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

    The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  18. Slow Orbit Feedback at the ALS Using Matlab

    SciTech Connect

    Portmann, G.

    1999-03-25

    The third generation Advanced Light Source (ALS) produces extremely bright and finely focused photon beams using undulatory, wigglers, and bend magnets. In order to position the photon beams accurately, a slow global orbit feedback system has been developed. The dominant causes of orbit motion at the ALS are temperature variation and insertion device motion. This type of motion can be removed using slow global orbit feedback with a data rate of a few Hertz. The remaining orbit motion in the ALS is only 1-3 micron rms. Slow orbit feedback does not require high computational throughput. At the ALS, the global orbit feedback algorithm, based on the singular valued decomposition method, is coded in MATLAB and runs on a control room workstation. Using the MATLAB environment to develop, test, and run the storage ring control algorithms has proven to be a fast and efficient way to operate the ALS.

  19. Forging of FeAl intermetallic compounds

    SciTech Connect

    Flores, O.; Juarez, J.; Campillo, B.; Martinez, L.; Schneibel, J.H.

    1994-09-01

    Much activity has been concentrated on the development of intermetallic compounds with the aim of improving tensile ductility, fracture toughness and high notch sensitivity in order to develop an attractive combination of properties for high and low temperature applications. This paper reports experience in processing and forging of FeAl intermetallic of B2 type. During the experiments two different temperatures were employed, and the specimens were forged after annealing in air, 10{sup {minus}2} torr vacuum and argon. From the results it was learned that annealing FeAl in argon atmosphere prior to forging resulted in better deformation behavior than for the other two environments. For the higher forging temperature used in the experiments (700C), the as-cast microstructure becomes partially recrystallized.

  20. A Learning Framework for the Small Business Environment

    ERIC Educational Resources Information Center

    Kelliher, Felicity; Henderson, Joan Bernadette

    2006-01-01

    Purpose: The aim of this article is to offer insight into the factors affecting individual and organisational learning in a small business; specifically the identification of the learning relationships that are unique to the small business environment. Design/methodology/approach: The authors apply Crossan et al.'s (1997, 1999) Organisational…

  1. Studies of 27Al NMR in EuAl4

    NASA Astrophysics Data System (ADS)

    Niki, H.; Nakamura, S.; Higa, N.; Kuroshima, H.; Toji, T.; Yogi, M.; Nakamura, A.; Hedo, M.; Nakama, T.; Ōnuki, Y.; Harima, H.

    2015-03-01

    EuAl4 orders antiferromagnetically at TN ≈ 16 K with an effective magnetic moment of 8.02 μB. In the paramagnetic phase, the magnetic susceptibility of EuAl4 follows the Curie-Weiss law with a positive Curie-Weiss temperature θP = +14 K. The antiferromagnetic state is changed into the field induced ferromagnetic state at a critical field Hc of approximately 2 T. In order to microscopically investigate the magnetic and electronic properties in EuAl4, the NMR measurements of EuAl4 have been carried out at temperatures between 2 and 300 K, applying an external magnetic field of approximately 6.5 T. The 27Al NMR spectra corresponding to Al(I) and Al(II) sites are obtained. From the 27Al NMR spectra, the isotropic part Kiso and anisotropic part Kaniso of Knight shift, and nuclear quadrupole frequncy νQ are obtained. The Kiso and Kaniso shift to negative side with decreasing temperature due to the RKKY interaction. These temperature dependences follow the Curie-Weiss law with θP = +14 K, which is consistent with that of the magnetic susceptibility. From the K - χ plot, the values of the hyperfine fields Hhf_iso and Hhf_aniso are -3.231 and -0.162 kOe/μB for Al(I) site, and -1.823 and -0.264 kOe/μB for Al(II) site, respectively. The values of νQ of 27Al nucleus for Al(I) and Al(II) sites are approximately 0.865 and 0.409 MHz, respectively. The nuclear relaxation time T1 of 27Al NMR for both sites is almost constant in the paramagnetic phase, while the value of 1/T1 is abruptly decreased in the ordered ferromagnetic state.

  2. Al-21Ti-23Cr high-temperature protective coating on TiAl intermetallic compounds by RF magnetron sputtering

    SciTech Connect

    Park, J.Y.; Lee, H.N.; Wee, D.M.; Park, S.W.; Oh, M.H.

    1997-12-31

    Ti-48Al specimens were coated with Al-21Ti-23Cr film at 200 W, 0.8 Pa and 573 K by RF magnetron sputtering. The oxidation behavior of the coated specimens was investigated through isothermal and cyclic oxidation tests, and the tensile deformation properties of the coated specimens were also investigated before and after oxidation. The isothermal and cyclic oxidation curves showed that the Al-21Ti-23Cr film was very effective in decreasing the oxidation rate of Ti-48Al. This excellent oxidation resistance is attributable to the formation of a protective Al{sub 2}O{sub 3} layer on the surface of the Al-21Ti-23Cr film. It was found from the results of the tensile test that the protective Al{sub 2}O{sub 3} layer on the surface of the Al-21Ti-23Cr film enabled the Ti-48Al to maintain its tensile properties in an oxidizing environment.

  3. ALS 2883: Analysis of spectroscopic features

    NASA Astrophysics Data System (ADS)

    Silva, A. R.; Levenhagen, R. S.; Künzel, R.; Leister, N. V.

    2014-10-01

    ALS 2883 (RA 13^{h} 02^{m} 47^{s}, DEC -63^{o} 50' 08'', M_{v} 10.1) is the first known radio pulsar with an emission B-type companion system, discovered in 1992. The Be companion of ALS 2883 has all line profiles in the visible range in emission. This emission is a common hallmark among many Be stars, and this effect is thought to be due to the presence of a circumstellar environment. Also, the star is orbiting a X-ray source as has been detected by the XMM-Newton Science Operation Center. In this study, we present the observations of ALS 2883 made at the OPD/LNA 1.60 m telescope with the Coudé spectrograph in the range 4000 to 5000 Å and S/N simeq 200, performed in April 2011. First-order estimations of T_{eff} and log g parameters have been performed through Johnson's UBV and JHK photometric calibrations. Projected rotation velocity V sin i has been estimated through the mean of the first zeroes of the Fourier transforms of neutral helium rotation profiles adopting linear, quadratic and square-root limb-darkening laws. The physical conditions of the circumstellar envelope were estimated through the solution of the radiative transport equation assuming local thermodynamic equilibrium within a disk-shaped circumstellar environment with a Keplerian velocity field. The radiative transport equation is solved assuming the Roche model as a boundary condition in the circumstellar environment. Iterating the computations with a downhill-simplex algorithm, this analysis leads to a best solution for an envelope with T simeq 9500 K, gas density ρ simeq 2 × 10^{-15} g.cm^{-3}, internal radius r_{i} simeq 8 R_{odot} and external radius r_e simeq 30 R_{odot}, rotating with V_{rot} simeq 140 km.s^{-1} and expanding with V_{exp} simeq 90 km.s^{-1}.

  4. In situ microscopy of rapidly heated nano-Al and nano-Al/WO{sub 3} thermites

    SciTech Connect

    Sullivan, Kyle T.; Zachariah, Michael R.; Chiou, Wen-An; Fiore, Richard

    2010-09-27

    The initiation and reaction mechanism of nano-Al and nano-Al thermites in rapid heating environments is investigated in this work. A semiconductor-based grid/stage was used, capable of in situ heating of a sample from room temperature to 1473 K, and at a rate of 10{sup 6} K/s, inside an electron microscope. Nano-Al was rapidly heated in a transmission electron microscope, and before and after images indicate that the aluminum migrates through the shell, consistent with a diffusion-based mechanism. A nano-Al/WO{sub 3} composite was then heated in a scanning electron microscope. The results indicate that a reactive sintering mechanism is occurring for the nano-Al/WO{sub 3} thermite, as the products are found to be in surface contact and significantly deformed after the heating pulse.

  5. Interfacial characterization of Al-Al thermocompression bonds

    NASA Astrophysics Data System (ADS)

    Malik, N.; Carvalho, P. A.; Poppe, E.; Finstad, T. G.

    2016-05-01

    Interfaces formed by Al-Al thermocompression bonding were studied by the transmission electron microscopy. Si wafer pairs having patterned bonding frames were bonded using Al films deposited on Si or SiO2 as intermediate bonding media. A bond force of 36 or 60 kN at bonding temperatures ranging from 400-550 °C was applied for a duration of 60 min. Differences in the bonded interfaces of 200 μm wide sealing frames were investigated. It was observed that the interface had voids for bonding with 36 kN at 400 °C for Al deposited both on Si and on SiO2. However, the dicing yield was 33% for Al on Si and 98% for Al on SiO2, attesting for the higher quality of the latter bonds. Both a bond force of 60 kN applied at 400 °C and a bond force of 36 kN applied at 550 °C resulted in completely bonded frames with dicing yields of, respectively, 100% and 96%. A high density of long dislocations in the Al grains was observed for the 60 kN case, while the higher temperature resulted in grain boundary rotation away from the original Al-Al interface towards more stable configurations. Possible bonding mechanisms and reasons for the large difference in bonding quality of the Al films deposited on Si or SiO2 are discussed.

  6. Studies of 27Al NMR in SrAl4

    NASA Astrophysics Data System (ADS)

    Niki, Haruo; Higa, Nonoka; Kuroshima, Hiroko; Toji, Tatsuki; Morishima, Mach; Minei, Motofumi; Yogi, Mamoru; Nakamura, Ai; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika; Harima, Hisatomo

    A charge density wave (CDW) transition at TCDW = 243 K and a structural phase (SP) transition at approximately 100 K occur in SrAl4 with the BaAl4-type body center tetragonal structure, which is the divalent and non-4f electron reference compound of EuAl4. To understand the behaviors of the CDW and SP transitions, the 27Al NMR measurements using a single crystal and a powder sample of SrAl4 have been carried out. The line width below TCDW is modulated by an electrical quadruple interaction between 27Al nucleus and CDW charge modulation. The incommensurate CDW state below TCDW changes into a different structure below TSP. The temperature dependences of Knight shifts of 27Al(I) and 27Al(II) show the different behaviors. The temperature variation of 27Al(I) Knight shift shows anomalies at the CDW and SP transition temperatures, revealing the shift to negative side below TCDW, which is attributable to the core polarization of the d-electrons. However, 27Al(II) Knight shift keeps almost constant except for the small shift due to the SP transition. The 1/T1T of 27Al(I) indicates the obvious changes due to the CDW and SP transitions, while that of 27Al(II) takes a constant value. The density of state at the Fermi level at Al(I) site below 60 K would be about 0.9 times less than that above TCDW.

  7. ALS Performance Summary - Update

    SciTech Connect

    Waters, A M; Brown, W D; Martz, Jr., H E

    2004-09-30

    High Energy Density Physics (HEDP) experiments play an important role in corroborating the improved physics codes that underlie LLNL's Stockpile Stewardship mission. Conducting these experiments, whether on the National Ignition Facility (NIF) or another national facility such as Omega, will require not only improvement in the diagnostics for measuring the experiment, but also detailed knowledge of the as-built target components and assemblies themselves. To assist in this effort, a defined set of well-known reference standards designed to represent a range of HEDP targets have been built and are being used to quantify the performance of different characterization techniques [Hibbard, et al. 2004]. Without the critical step of using reference standards for qualifying characterization tools there can be no verification of either commercial or internally-developed characterization techniques and thus an uncertainty in the input to the physics code models would exist.

  8. Tribological Properties of Ti(Al,O)/Al2O3 Composite Coating by Thermal Spraying

    NASA Astrophysics Data System (ADS)

    Salman, Asma; Gabbitas, Brian; Cao, Peng; Zhang, Deliang

    The use of thermal spray coatings provides protection to the surfaces operating in severe environments. The main goal of the current work is to investigate the possibility of using a high velocity air fuel (HVAF) thermally sprayed wear resistant Ti(Al,O)/Al2O3 coating on tool steel (H13) which is used for making dies for aluminium high pressure die casting and dummy blocks aluminium extrusion. A feedstock of Ti(Al,O)/Al2O3 composite powder was produced from a mixture of Al and TiO2 powders by high energy mechanical milling, followed by a thermal reaction process. The feedstock was then thermally sprayed using a high velocity air-fuel (HVAF) technique onto H13 steel substrates to produce a composite coating. The present study describes and compares the tribological properties such as friction and sliding wear rate of the coating both at room and high temperature (700°C). The wear resistance of the coating was investigated by a tribometer using a spherical ended alumina pin as a counter body under dry and lubricating conditions. The results showed that composite coating has lower wear rate at high temperature than at room temperature without using lubricant. The composite coating was characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD). This paper reports the experimental observations and discusses the wear resistance performance of the coatings at room and high temperatures.

  9. Doppelthydrophile Blockcopolymere als Mineralisationstemplate

    NASA Astrophysics Data System (ADS)

    Kasparova, Pavla

    2002-07-01

    Die vorliegende Arbeit beschäftigt sich mit der Synthese und den Eigenschaften von doppelthydrophilen Blockcopolymeren und ihrer Anwendung in einem biomimetischen Mineralisationsprozeß von Calciumcarbonat und Bariumsulfat. Doppelthydrophile Blockcopolymere bestehen aus einem hydrophilen Block, der nicht mit Mineralien wechselwirkt und einem zweiten Polyelektrolyt-Block, der stark mit Mineraloberflächen wechselwirkt. Diese Blockcopolymere wurden durch ringöffnende Polymerisation von N-carboxyanhydriden (NCA's) und a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 als Initiator hergestellt. Die hergestellten Blockcopolymere wurden als effektive Wachstumsmodifikatoren für die Kristallisation von Calciumcarbonat und Bariumsulfat Mineralien eingesetzt. Die so erhaltenen Mineralpartikel (Kugeln, Hantel, eiförmige Partikel) wurden durch Lichtmikroskopie in Lösung, SEM und TEM charakterisiert. Röntgenweitwinkelstreuung (WAXS) wurde verwendet, um die Modifikation von Calciumcarbonat zu ermitteln und die Größe der Calciumcarbonat- und Bariumsulfat-Nanopartikel zu ermitteln. This work describes the synthesis and characterization of double hydrophilic block copolymers and their use in a biomimetic mineralization process of Calcium Carbonate and Barium Sulfate. Double hydrophilic block copolymers consist of a hydrophilic block that does not interact with minerals and another hydrophilic polyelectrolyte block that strongly interacts with mineral surfaces. These polymers were synthesised via ring opening polymerisation of N-carboxyanhydride (NCA), and the first hydrophilic block a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 was used as an initiator. The prepared block copolymers were used as effective crystal growth modifiers to control the crystallization of Calcium Carbonate and Barium Sulfate minerals. The resulting mineral particles (spheres, dumbbells, egg-like particles) were characterised by light microscopy in solution, by SEM, and by TEM. X-Ray scattering

  10. Processing of Soot in an Urban Environment: Case Study from the Mexico City Metropolitan Area

    SciTech Connect

    Johnson, Kirsten S.; Zuberi, Bilal M.; Molina, Luisa; Molina, Mario J.; Iedema, Martin J.; Cowin, James P.; Gaspar, Daniel J.; Wang, Chong M.; Laskin, Alexander

    2005-11-14

    Chemical composition, size, and mixing state of atmospheric particles are critical in determining their e ffects on the environment. There is growing evidence that soot aerosols play a particularly important role in both climate and human health, but still relatively little is known of their physical and chemical nature. In addition, the atmo- 5 spheric residence times and removal mechanisms for soot are neither well understood nor adequately represented in regional and global climate models. To investigate the effect of locality and residence time on properties of soot and mixing state in a polluted urban environment, particles of diameter 0.2–2.0 µm were collected in the Mexico City Metropolitan Area (MCMA) during the MCMA-2003 field campaign from various sites 10 within the city. Individual particle analysis by di fferent electron microscopy methods coupled with energy dispersed X-ray spectroscopy, and secondary ionization mass spectrometry show that freshly-emitted soot particles become rapidly processed in the MCMA. Whereas fresh particulate emissions from mixed-tra ffic are almost entirely carbonaceous, consisting of soot aggregates with liquid coatings suggestive of unburned 15 lubricating oil and water, ambient soot particles which have been processed for less than a few hours are heavily internally mixed, primarily with ammonium sulfate. Single particle analysis suggests that this mixing occurs through several mechanisms that require further investigation. In light of previously published results, the internally-mixed nature of processed soot particles is expected to a ffect heterogeneous chemistry on 20 the soot surface, including interaction with water during wet-removal.

  11. Relation between surface slip topography and stress corrosion cracking in Ti-8 wt % Al

    NASA Technical Reports Server (NTRS)

    Boyd, J. D.; Hoagland, R. G.

    1974-01-01

    The deformation behavior of Ti-8 wt % Al has been investigated in an inert environment (air), and an aggressive environment (salt water). Details of surface slip geometry were examined by high resolution surface replicas at various stages of deformation in both environments. Specimens aged to contain a fine dispersion of Ti3Al precipitates failed by subcritical crack growth in salt water, whereas specimens in the single phase condition showed no effects of environment on the yield or fracture characteristics. The Ti3Al precipitates produce little change in strength level or slip character compared to the single phase alloy, and there is no evidence of any effects of environment on the character of surface slip. Rather, the presence of trenches along slip bands on the surface of aged specimens suggest that the specific effect of the Ti3Al precipitates is to render the surface slip steps chemically active relative to the surrounding matrix by slip induced dissolution of the particles.

  12. Response to Julian et al. (2015) "Comment on and Reinterpretation of Gabriel et al. (2014) `Fish Mercury and Surface Water Sulfate Relationships in the Everglades Protection Area'"

    NASA Astrophysics Data System (ADS)

    Gabriel, Mark C.; Axelrad, Don; Orem, William; Osborne, Todd Z.

    2015-06-01

    The purpose of this forum is to respond to a rebuttal submitted by Julian et al., Environ Manag 55:1-5, 2015 where they outlined their overall disagreement with the data preparation, methods, and interpretation of results presented in Gabriel et al. (Environ Manag 53:583-593, 2014). Here, we provide background information on the research premise presented in Gabriel et al. (Environ Manag 53:583-593, 2014) and provide a defense for this work using five themes. In spite of what Julian et al. perceive as limitations in the sampling methods and analytical tools used for this work, the relationships found between fish total mercury and surface water sulfate concentrations in Gabriel et al. (Environ Manag 53:583-593, 2014) are comparable to relationships between pore water methylmercury (MeHg) and pore water sulfate found in past studies indicating that sulfate is important to MeHg production and bioaccumulation in the Everglades. Julian et al. state "…there is no way to justify any ecosystem-wide sulfur strategy as a management approach to reduce mercury risk in the (Everglades) as suggested by Gabriel et al. (Environ Manag 53:583-593, 2014), Corrales et al. (Sci Tot Environ 409:2156-2162, 2011) and Orem et al. (Rev Environ Sci Technol 41 (S1):249-288, 2011)." We disagree, and having stated why sulfate input reduction to the Everglades may be the most effective means of reducing mercury in Everglades fish, it is important that research on sulfur and mercury biogeochemistry continues. If further studies support the relationship between sulfate loading reduction and MeHg reduction, sulfur mass balance studies should commence to (1) better quantify agricultural and connate seawater sulfate inputs and (2) define opportunities to reduce sulfate inputs to the Everglades ecosystem.

  13. Response to Julian et al. (2015) "comment on and reinterpretation of Gabriel et al. (2014) 'fish mercury and surface water sulfate relationships in the everglades protection area'".

    PubMed

    Gabriel, Mark C; Axelrad, Don; Orem, William; Osborne, Todd Z

    2015-06-01

    The purpose of this forum is to respond to a rebuttal submitted by Julian et al., Environ Manag 55:1-5, 2015 where they outlined their overall disagreement with the data preparation, methods, and interpretation of results presented in Gabriel et al. (Environ Manag 53:583-593, 2014). Here, we provide background information on the research premise presented in Gabriel et al. (Environ Manag 53:583-593, 2014) and provide a defense for this work using five themes. In spite of what Julian et al. perceive as limitations in the sampling methods and analytical tools used for this work, the relationships found between fish total mercury and surface water sulfate concentrations in Gabriel et al. (Environ Manag 53:583-593, 2014) are comparable to relationships between pore water methylmercury (MeHg) and pore water sulfate found in past studies indicating that sulfate is important to MeHg production and bioaccumulation in the Everglades. Julian et al. state "…there is no way to justify any ecosystem-wide sulfur strategy as a management approach to reduce mercury risk in the (Everglades) as suggested by Gabriel et al. (Environ Manag 53:583-593, 2014), Corrales et al. (Sci Tot Environ 409:2156-2162, 2011) and Orem et al. (Rev Environ Sci Technol 41 (S1):249-288, 2011)." We disagree, and having stated why sulfate input reduction to the Everglades may be the most effective means of reducing mercury in Everglades fish, it is important that research on sulfur and mercury biogeochemistry continues. If further studies support the relationship between sulfate loading reduction and MeHg reduction, sulfur mass balance studies should commence to (1) better quantify agricultural and connate seawater sulfate inputs and (2) define opportunities to reduce sulfate inputs to the Everglades ecosystem. PMID:25860595

  14. Siderophore production in high iron environments

    NASA Astrophysics Data System (ADS)

    Bennett, S. A.; Hoffman, C. L.; Moffett, J. W.; Edwards, K. J.

    2010-12-01

    Up until recently, the geochemical cycling of Fe in deep sea hydrothermal plumes has assumed to be inorganically dominated, resulting in quantitative precipitation of all hydrothermally sourced Fe to the seafloor. Recent detection of organic Fe binding ligands within both the dissolved and particulate phase (Bennett et al., 2008; Toner et al., 2009), suggests that hydrothermally sourced Fe may be important on a global scale (Tagliabue et al., 2010). The source of these organic ligands is currently unknown; hypotheses include the possible entrainment of organic carbon from the biologically rich diffuse flow areas, or in-situ production from microbial processes. However, the microbial production of organic ligands is only expected when Fe is a limited micronutrient, which is not the case in the hydrothermal environment. The importance of Fe cycling microorganisms within hydrothermal systems was previously overlooked due to the poor energetics with regards to Fe oxidation and reduction. But their recent detection within the hydrothermal system, both around low temperature Fe rich mineral deposits and within hydrothermal plumes (Edwards et al., 2004; Sylvan et al., In prep) suggests that they may have an important role in the hydrothermal Fe cycle, potentially resulting in an interplay between Fe and organic carbon. Within the laboratory, we have carried out experiments to investigate an Fe oxidizing bacteria in a variety of high Fe environments. We have detected both the production of siderophores and an increase in reduced Fe when the Fe oxidizing bacteria is exposed to both Fe(III) and Fe(II) rich minerals. The role of these microbes in the mineral dissolution of Fe sulfides along the seafloor and within the hydrothermal plume, may have important implications on the speciation of Fe and the role of siderophores in the marine environment. Bennett, S.A. et al. 2008. EPSL, 270: 157-167. Edwards, K.J. et al. 2004. Geomicrobiology Journal, 21: 393-404. Sylvan, J.B. et al

  15. Interfacial reactions and oxidation behavior of Al 2O 3 and Al 2O 3/Al coatings on an orthorhombic Ti 2AlNb alloy

    NASA Astrophysics Data System (ADS)

    Li, H. Q.; Wang, Q. M.; Gong, J.; Sun, C.

    2011-02-01

    The uniform and dense Al2O3 and Al2O3/Al coatings were deposited on an orthorhombic Ti2AlNb alloy by filtered arc ion plating. The interfacial reactions of the Al2O3/Ti2AlNb and Al2O3/Al/Ti2AlNb specimens after vacuum annealing at 750 °C were studied. In the Al2O3/Ti2AlNb specimens, the Al2O3 coating decomposed significantly due to reaction between the Al2O3 coating and the O-Ti2AlNb substrate. In the Al2O3/Al/Ti2AlNb specimens, a γ-TiAl layer and an Nb-rich zone came into being by interdiffusion between the Al layer and the O-Ti2AlNb substrate. The γ-TiAl layer is chemically compatible with Al2O3, with no decomposition of Al2O3 being detected. No internal oxidation or oxygen and nitrogen dissolution zone was observed in the O-Ti2AlNb alloy. The Al2O3/Al/Ti2AlNb specimens exhibited excellent oxidation resistance at 750 °C.

  16. Intermetallic compound formation at Cu-Al wire bond interface

    SciTech Connect

    Bae, In-Tae; Young Jung, Dae; Chen, William T.; Du Yong

    2012-12-15

    Intermetallic compound (IMC) formation and evolution at Cu-Al wire bond interface were studied using focused ion beam /scanning electron microscopy, transmission electron microscopy (TEM)/energy dispersive x-ray spectroscopy (EDS), nano beam electron diffraction (NBED) and structure factor (SF) calculation. It was found that discrete IMC patches were formed at the Cu/Al interface in as-packaged state and they grew toward Al pad after high temperature storage (HTS) environment at 150 Degree-Sign C. TEM/EDS and NBED results combined with SF calculation revealed the evidence of metastable {theta} Prime -CuAl{sub 2} IMC phase (tetragonal, space group: I4m2, a = 0.404 nm, c= 0.580 nm) formed at Cu/Al interfaces in both of the as-packaged and the post-HTS samples. Two feasible mechanisms for the formation of the metastable {theta} Prime -CuAl{sub 2} phase are discussed based on (1) non-equilibrium cooling of wire bond that is attributed to highly short bonding process time and (2) the epitaxial relationships between Cu and {theta} Prime -CuAl{sub 2}, which can minimize lattice mismatch for {theta} Prime -CuAl{sub 2} to grow on Cu.

  17. Design Characteristics of Virtual Learning Environments: State of Research

    ERIC Educational Resources Information Center

    Mueller, Daniel; Strohmeier, Stefan

    2011-01-01

    Virtual learning environments constitute current information systems' category for electronically supported training and development in (higher) education(al) and vocational training settings. Frequently expected advantages of using virtual learning environments refer, for instance, to the efficiency, individuality, ubiquity, timeliness and…

  18. Rub' al Khali, Arabia

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Rub' al Khali is one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula. It includes parts of Oman, United Arab Emirates, and Yemen. The desert covers 650,000 square kilometers, more than the area of France. Largely unexplored until recently, the desert is 1000 km long and 500 km wide. The first documented journeys made by Westerners were those of Bertram Thomas in 1931 and St. John Philby in 1932. With daytime temperatures reaching 55 degrees Celsius, and dunes taller than 330 meters, the desert may be one of the most forbidding places on Earth.

    The image was acquired December 2, 2005, covers an area of 54.8 x 61.9 km, and is located near 20.7 degrees north latitude, 53.6 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  19. Complete genome sequence of Aeromonas hydrophila AL06-06

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aeromonas hydrophila occurs in freshwater environments and infects fish and mammals. In this work, we report the complete genome sequence of Aeromonas hydrophila AL06-06, which was isolated from diseased goldfish and is being used for comparative genomic studies with A. hydrophila strains causing ba...

  20. Hydrogen environment effects on beryllium and titanium aluminides

    NASA Technical Reports Server (NTRS)

    Fritzemeier, L. G.; Jacinto, M. A.

    1990-01-01

    The NASP program has intensively studied the hydrogen-environment embrittlement (HEE) susceptibility of Be, alpha(2)-Ti3Al, and gamma-TiAl. Tensile tests are being conducted on candidate aerospace structure and propulsion candidate materials from each of the three groups, at temperatures in the -130 to +204 C range, in both 0.1 MPa and 13.8 MPa He and H2 environments, using SEM and TEM to discern the details of environmental effects. It has been established that while alpha(2) Ti3Al is HEE-susceptible even in the room-temperature and 13.8 MPa environment, neither Be nor gamma-TiAl are susceptible, even at the highest temperature tested.

  1. Coatings in space environment. [for satellite thermal control

    NASA Technical Reports Server (NTRS)

    Triolo, J. J.; Heaney, J. B.; Hass, G.

    1978-01-01

    The behavior in space environment of evaporated Al uncoated and coated with reactively deposited silicon oxide (SiOx), electron beam evaporated SiO2 and Al2O3, and Al and Ag coated with double layers of Al2O3 + SiOx is compared with metallized Teflon and Kapton, anodized Al (Alzak), and white paints. Flight data from three calorimetric experiments and one reflectometer flown in different orbital environments are compared with laboratory test data. The results demonstrate that evaporated thin films are extremely versatile and stable coatings for space applications. Through the use of control samples studied in different laboratory tests and monitored for up to 12,000 hours of solar exposure in different orbits, a classification of orbital severity and an estimate of laboratory simulation accuracy is obtained.

  2. Decoherence control in different environments

    SciTech Connect

    Paavola, J.; Maniscalco, S.

    2010-07-15

    We investigate two techniques for controlling decoherence, focusing on the crucial role played by the environmental spectrum. We show how environments with different spectra lead to very different dynamical behaviors. Our study clearly proves that such differences must be taken into account when designing decoherence control schemes. The two techniques we consider are reservoir engineering and quantum Zeno control. We focus on a quantum harmonic oscillator initially prepared in a nonclassical state and derive analytically its non-Markovian dynamics in the presence of different bosonic thermal environments. On the one hand, we show how, by modifying the spectrum of the environment, it is possible to prolong or reduce the life of a Schroedinger cat state. On the other hand, we study the effect of nonselective energy measurements on the degradation of quantumness of initial Fock states. In this latter case, we see that the crossover between quantum Zeno and anti-Zeno effects, discussed by Maniscalco et al. [Phys. Rev. Lett. 97, 130402 (2006)], is highly sensitive to the details of the spectrum. In particular, for certain types of spectra, even very small variations of the system frequency may cause a measurement-induced acceleration of decoherence rather than its inhibition.

  3. Environment surveys. [monitoring and protection of environment

    NASA Technical Reports Server (NTRS)

    Greenwood, L. R.

    1974-01-01

    Environment applications are concerned with the quality, protection, and improvement of water, land, and air resources and, in particular, with the pollution of these resources caused by man and his works, as well as changes to the resources due to natural phenomena (for example, drought and floods). The broad NASA objectives related to the environment are directed toward the development and demonstration of the capability to monitor remotely and assess environmental conditions related to water quality, land and vegetation quality, wildlife resources, and general environment. The contributions of ERTS-1 to these subdiscipline areas are broadly summarized.

  4. Undulators at the ALS

    SciTech Connect

    Hoyer, E.; Akre, J.; Chin, J.

    1994-07-01

    At Lawrence Berkeley Laboratory`s (LBL) Advanced Light Source (ALS), three 4.6 m long undulators have been completed, tested and installed. A fourth is under construction. The completed undulators include two 5.0 cm period length, 89 period devices (U5.0s) which achieve a 0.85 T effective field at a 14 mm minimum gap and a 8.0 cm period length, 55 period device (U8.0) that reaches a 1.2 T effective field at a 14 mm minimum gap. The undulator under construction is a 10.0 cm period length, 43 period device (U10.0) that is designed to achieve 0.98 T at a 23 mm gap. Undulator magnetic gap variation (rms) is within 25 microns over the periodic structure length. Reproducibility of the adjustable magnetic gap has been measured to be within +/{minus} 5 microns. Gap adjusting range is from 14 mm to 210 mm, which can be scanned in one minute. The 5.1 m long vacuum chambers are flat in the vertical direction to within 0.74 mm and straight in the horizontal direction to within 0.08 mm over the 4.6 m magnetic structure sections. Vacuum chamber base pressures after UHV beam conditioning are. in the mid 10{sup {minus}11} Torr range and storage ring operating pressures with full current are in the low 10{sup {minus}10} Torr range. Measurements show that the uncorrelated magnetic field errors are 0.23%, and 0.20% for the two U5.Os and the U8.0 respectively and that the field integrals are small over the 1 cm by 6 cm beam aperture. Device description, fabrication, and measurements are presented.

  5. Cation disorder determined by MAS {sup 27}Al NMR in high dose neutron irradiated spinel

    SciTech Connect

    Cooper, E.A.; Sickafus, K.E.; Hughes, C.D.; Earl, W.L.; Hollenberg, G.W.; Garner, F.A.; Bradt, R.C.

    1995-12-31

    Spinel (MgAl{sub 2}O{sub 4}) single crystals which had been neutron irradiated to high doses (53-250 dpa) were examined using {sup 27}Al magic angle spinning (MAS) nuclear magnetic resonance (NMR). The sensitivity of this procedure to a specific cation (Al) residing in different crystallographic environments allowed one to determine the distribution of the Al between the two cation sites in the spinel structure. The samples were irradiated at two different temperatures (400 and 750{degrees}C) and various doses. These results indicate that the Al was nearly fully disordered over the two lattice sites after irradiation.

  6. EDITORIAL: Siberia Integrated Regional Study: multidisciplinary investigations of the dynamic relationship between the Siberian environment and global climate change

    NASA Astrophysics Data System (ADS)

    Gordov, E. P.; Vaganov, E. A.

    2010-03-01

    ] Groisman P Y et al 2009 The Northern Eurasia Earth Science Partnership: an example of science applied to societal needs Bull. Am. Meteorol. Soc. 90 671-88 [6] Shiklomanov and Lammers R L 2009 Record Russian river discharge in 2007 and the limits of analysis Environ. Res. Lett. 4 045015 [7] Tchebakova N M, Parfenova E and Soja A J 2009 The effects of climate, permafrost and fire on vegetation change in Siberia in a changing climate Environ. Res. Lett. 4 045013 [8] Soja A et al 2007 Climate-induced boreal forest change: predictions versus current observations Global Planet. Change 56 274-96 [9] Groisman P Y and Bartalev S V 2007 Northern Eurasia Earth Science Partnership Initiative (NEESPI): science plan overview Global Planet. Change 56 215-34 [10] Gordov E P and Begni G 2005 Siberia integrated regional study development Comput. Technol. 10 149-55 [11] Gordov E P, Begni G, Heiman M, Kabanov M V, Lykossov V N, Shvidenko A Z and Vaganov E A 2006 Siberia integrated regional study as a basis for international scientific cooperation Comput. Technol. 11 16-28 [12] Baklanov A and Gordov E P 2006 Man-induced environmental risks: monitoring, management and remediation of man-made changes in Siberia Comput. Technol. 11 162-71 [13] Gordov E P 2004 Computational and information technologies for environmental sciences Comput. Technol. 9 3-10 Gordov E P 2004 Modern tendencies in regional environmental studies Geogr. Nat. Resources. (special issue) 11-18 Akhlyostin A Yu and Fazliev A Z 2003 Software for presentation of scientific information in the framework of a WEB portal Proc. SPIE 5396 111-8 Gordov E P, De Rudder A, Lykosov V N, Fazliev A Z and Fedra K 2004 Web-portal ATMOS as basis for integrated investigations of Siberia environment Comput. Technol. 9 3-13 Gordov E P, Lykosov V N and Fazliev A Z 2006 Web portal on environmental sciences 'ATMOS' Adv. Geosci. 8 33-8 Okladnikov I G and Titov A G 2006 Web-system for processing and visualization of meteorological data Environmental

  7. Science Laboratory Environment and Academic Performance

    NASA Astrophysics Data System (ADS)

    Aladejana, Francisca; Aderibigbe, Oluyemisi

    2007-12-01

    The study determined how students assess the various components of their science laboratory environment. It also identified how the laboratory environment affects students' learning outcomes. The modified ex-post facto design was used. A sample of 328 randomly selected students was taken from a population of all Senior Secondary School chemistry students in a state in Nigeria. The research instrument, Science Laboratory Environment Inventory (SLEI) designed and validated by Fraser et al. (Sci Educ 77:1-24, 1993) was administered on the selected students. Data analysis was done using descriptive statistics and Product Moment Correlation. Findings revealed that students could assess the five components (Student cohesiveness, Open-endedness, Integration, Rule clarity, and Material Environment) of the laboratory environment. Student cohesiveness has the highest assessment while material environment has the least. The results also showed that the five components of the science laboratory environment are positively correlated with students' academic performance. The findings are discussed with a view to improving the quality of the laboratory environment, subsequent academic performance in science and ultimately the enrolment and retaining of learners in science.

  8. Thermal Modeling of Al-Al and Al-Steel Friction Stir Spot Welding

    NASA Astrophysics Data System (ADS)

    Jedrasiak, P.; Shercliff, H. R.; Reilly, A.; McShane, G. J.; Chen, Y. C.; Wang, L.; Robson, J.; Prangnell, P.

    2016-07-01

    This paper presents a finite element thermal model for similar and dissimilar alloy friction stir spot welding (FSSW). The model is calibrated and validated using instrumented lap joints in Al-Al and Al-Fe automotive sheet alloys. The model successfully predicts the thermal histories for a range of process conditions. The resulting temperature histories are used to predict the growth of intermetallic phases at the interface in Al-Fe welds. Temperature predictions were used to study the evolution of hardness of a precipitation-hardened aluminum alloy during post-weld aging after FSSW.

  9. Fractographic observations of Ti-6Al-4V alloy fatigued in vacuum.

    NASA Technical Reports Server (NTRS)

    Ritter, D. L.; Wei, R. P.

    1971-01-01

    These observations were made as part of a study of the influence of temperature and chemical environment on fatigue-crack growth. The results obtained, along with additional fractographic results in other environments, suggest that the mechanism for fatigue-crack growth in the Ti-6Al-4V alloy is basically similar (striations are observed) for a wide range of environments. In addition to ?vacuum,' these environments include distilled water, ?dry' and ?wet' air, ?dry' hydrogen, and ?dry' and ?wet' argon.

  10. Modeling neuronal vulnerability in ALS.

    PubMed

    Roselli, Francesco; Caroni, Pico

    2014-08-20

    Using computational models of motor neuron ion fluxes, firing properties, and energy requirements, Le Masson et al. (2014) reveal how local imbalances in energy homeostasis may self-amplify and contribute to neurodegeneration in ALS. PMID:25144872

  11. Philosophieren als Unterrichtsprinzip im Mathematikunterricht

    NASA Astrophysics Data System (ADS)

    Meerwaldt, Diana

    Philosophieren und Mathematik scheinen zunächst gegensätzliche Bereiche zu sein, die sich kaum vereinbaren lassen. Dies trifft für eine Auffassung zu, die Philosophieren als "Gerede" disqualifiziert und Mathematik als eine reine "Formelwissenschaft" begreift. Beide Auffassungen werden den Gegenständen nicht gerecht.

  12. Stabilizing the Policy Environment

    ERIC Educational Resources Information Center

    Johnston, A. P.

    1977-01-01

    Organizations seek stability in the policy environment, initially through direct control mechanism, but depending on risk propensity and uncertainty of the environment, through other means as well. A repertoire of seven such means are described and discussed. (Author/IRT)

  13. Environments for Development

    ERIC Educational Resources Information Center

    Grabinski, C. Joanne

    2005-01-01

    This chapter considers Robert Kegan's concept of holding environments, as well as six steps necessary for creation of new or adaptation of existing learning environments that facilitate adult development across the life course.

  14. Characteristics of CeCoIn5/Al/AlOx/Nb and CeCoIn5/Al/AlOx/Al Tunnel Junctions

    SciTech Connect

    Petrovic, C.; Nevirkovets, I.P.; Chernyashevskyy, O.; Hu, R.; Ketterson, J.B.; Sarma, B.K.

    2009-03-03

    We report characteristics of CeCoIn{sub 5}/Al/AlO{sub x}/Nb and CeCoIn{sub 5}/Al/AlO{sub x}/Al tunnel junctions fabricated on the (0 0 1) surface of CeCoIn{sub 5} crystal platelets. The main result of this work is the observation of a low Josephson current (as compared with that expected from the Ambegaokar-Baratoff formula), which is consistent with idea that the order parameter in the heavy-fermion superconductor CeCoIn{sub 5} has unconventional pairing symmetry.

  15. Fun with the Environment.

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC.

    This self-contained activity booklet is designed to teach young elementary students about their environment. Information about the environment and people's interaction with it are presented in cartoon and coloring book form. Drawings and simple vocabulary explain how the environment is polluted and natural resources wasted, as well as ways that…

  16. Computing environment logbook

    DOEpatents

    Osbourn, Gordon C; Bouchard, Ann M

    2012-09-18

    A computing environment logbook logs events occurring within a computing environment. The events are displayed as a history of past events within the logbook of the computing environment. The logbook provides search functionality to search through the history of past events to find one or more selected past events, and further, enables an undo of the one or more selected past events.

  17. Schoolheads and the Environment.

    ERIC Educational Resources Information Center

    Wolff, Bretta Weiss; Werner, Pat

    1999-01-01

    Examines what the prepared environment means to the Heads of Montessori schools. Maintains that the physical environment must be safe, healthful, aesthetically pleasing, and communicative to all the school's constituents. Suggests that the psychological environment is determined by underlying beliefs guiding expectations and actions of…

  18. Environments, Teacher's Guide.

    ERIC Educational Resources Information Center

    California Univ., Berkeley. Science Curriculum Improvement Study.

    The Science Curriculum Improvement Study has developed this teacher's guide to Environments, the fourth part of a six unit life science curriculum sequence. The six basic units, emphasizing organism-environment interactions, are organisms, life cycles, populations, environments, communities, and ecosystems, and make use of scientific and…

  19. Chemical shielding properties for BN, BP, AlN, and AlP nanocones: DFT studies

    NASA Astrophysics Data System (ADS)

    Mirzaei, Mahmoud; Yousefi, Mohammad; Meskinfam, Masoumeh

    2012-06-01

    The properties of boron nitride (BN), boron phosphide (BP), aluminum nitride (AlN), and aluminum phosphide (AlP) nanocones were investigated by density functional theory (DFT) calculations. The investigated structures were optimized and chemical shielding (CS) properties including isotropic and anisotropic CS parameters were calculated for the atoms of the optimized structures. The magnitudes of CS parameters were observed to be mainly dependent on the bond lengths of considered atoms. The results indicated that the atoms could be divided into atomic layers due to the similarities of their CS properties for the atoms of each layer. The trend means that the atoms of each layer detect almost similar electronic environments. Moreover, the atoms at the apex and mouth of nanocones exhibit different properties with respect to the other atomic layers.

  20. Thermal magnetic behaviour of Al-substituted haematite mixed with clay minerals and its geological significance

    NASA Astrophysics Data System (ADS)

    Jiang, Zhaoxia; Liu, Qingsong; Zhao, Xiangyu; Jin, Chunsheng; Liu, Caicai; Li, Shihu

    2015-01-01

    Clay minerals and Al-substituted haematite (Al-hm) usually coexist in soils and sediments. However, effects of clay minerals on Al-hm during thermal magnetic measurements in argon environment have not been well studied. In order to quantify such effects, a series of Al-hm samples were synthesized, and were then mixed with clay minerals (illite, chlorite, kaolinite and Ca-montmorillonite). The temperature dependence of magnetic susceptibility curves in an argon environment showed that Al-substituted magnetite was produced during the thermal treatment via the reduction of Al-hm by the clay mineral, which leads to a significant magnetic enhancement of the thermal products. In addition, the reductive capacity varies among different types of clay minerals, that is, illite > chlorite > kaolinite > Ca-montmorillonite. Furthermore, the iron content in the clay minerals and Al content of Al-hm are two predominant factors controlling the reduced haematite content. The iron is released from the clay minerals and provides the reducing agent, while Al decreases the crystallinity of haematite and thus facilitates the chemical reaction. Therefore, the thermal magnetic measurements can be used to quantify the Al content of Al-hm in natural samples. Our study provides significant information for palaeomagnetism and environmental magnetism studies, such as thermal magnetic analysis and palaeomagnetic intensity reconstruction using ancient pottery and kilns.

  1. How does an Al-hyperaccumulator plant respond to a natural field gradient of soil phytoavailable Al?

    PubMed

    Serrano, H C; Pinto, M J; Martins-Loução, M A; Branquinho, C

    2011-09-01

    The physiological ability of plants to cope with Al-toxicity has attracted considerable attention. In this study we used an endemic Al-hyperaccumulator plant, Plantago almogravensis, which is the only known representative of the Plantaginaceae with this trait growing under a field gradient of Al, to understand the root and shoot patterns of Al accumulation and tolerance in its natural environment. We analysed phytoavailable elements in the soil and their accumulation in the plant. For the first time under field conditions, the accumulation pattern of an Al-hyperaccumulator showed a saturation curve with a maximum accumulation capacity being reached (ca. 3.0 mg g(-1)). The Al toxicity was not associated with the expected reduction in the Ca and Mg uptake by the plant. Iron was accumulated in a more linear pattern. The magnitude and the proportion of the elements found in the apoplastic fraction of the root, compared to the soil and plant internal fractions, suggested that the control of uptake occurs at the rhizospheric level. Unlike the majority of the Al-hyperaccumulator plants that are found in tropical humid areas, this plant is described from a sub-arid Mediterranean climate, subject to drought conditions which give it a unique status that deserves to be studied further. PMID:21774964

  2. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified...

  3. 40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified...

  4. Stimulated emission in AlGaN/AlGaN quantum wells with different Al content

    NASA Astrophysics Data System (ADS)

    Mickevičius, J.; Jurkevičius, J.; Kazlauskas, K.; Žukauskas, A.; Tamulaitis, G.; Shur, M. S.; Shatalov, M.; Yang, J.; Gaska, R.

    2012-02-01

    Stimulated emission (SE) is studied in AlGaN/AlGaN multiple quantum wells (MQWs) with different Al content grown on sapphire substrate. The spectra of spontaneous and stimulated emission and their transformations with increasing temperature as well as stimulated emission thresholds were measured in the temperature range from 8 to 300 K. Phonon-assisted band broadening in low-Al-content MQWs and double-scaled potential profile in high-Al-content MQWs were observed in the samples and linked with carrier localization conditions. The temperature dependence of the stimulated emission threshold was similar in the samples where the stimulated transitions occur between extended states and in the samples where the transitions occur in localized states. The stimulated emission threshold depends predominantly on the density of nonradiative recombination centers.

  5. Spacecraft Environment Interactions

    NASA Technical Reports Server (NTRS)

    Garrett, Henry B.; Jun, Insoo

    2011-01-01

    As electronic components have grown smaller in size and power and have increased in complexity, their enhanced sensitivity to the space radiation environment and its effects has become a major source of concern for the spacecraft engineer. As a result, the description of the sources of space radiation, the determination of how that radiation propagates through material, and, ultimately, how radiation affects specific circuit components are primary considerations in the design of modern spacecraft. The objective of this paper will be to address the first 2 aspects of the radiation problem. This will be accomplished by first reviewing the natural and man-made space radiation environments. These environments include both the particulate and, where applicable, the electromagnetic (i.e., photon) environment. As the "ambient" environment is typically only relevant to the outer surface of a space vehicle, it will be necessary to treat the propagation of the external environment through the complex surrounding structures to the point inside the spacecraft where knowledge of the internal radiation environment is required. While it will not be possible to treat in detail all aspects of the problem of the radiation environment within a spacecraft, by dividing the problem into these parts-external environment, propagation, and internal environment-a basis for understanding the practical process of protecting a spacecraft from radiation will be established. The consequences of this environment will be discussed by the other presenters at this seminar.

  6. Medical application of 26Al

    NASA Astrophysics Data System (ADS)

    Steinhausen, C.; Gerisch, P.; Heisinger, B.; Hohl, Ch.; Kislinger, G.; Korschinek, G.; Niedermayer, M.; Nolte, E.; Dumitru, M.; Alvarez-Brückmann, M.; Schneider, M.; Ittel, T. H.

    1996-06-01

    Accelerator mass spectrometry (AMS) measurements with 26Al as tracer were performed in order to study the aluminium metabolism and anomalies in the human body and in rats. In particular, the differences between healthy volunteers and patients with renal failure were investigated. The obtained data points of 26Al in blood and urine were described by an open compartment model with three peripheral compartments. It was found that the minimum of peripheral compartments needed to describe 26Al concentrations in blood and urine over a time period of three years is at least three.

  7. Effect of silicate on the formation and stability of Ni-Al LDH at the γ-Al2O3 surface.

    PubMed

    Tan, Xiaoli; Fang, Ming; Ren, Xuemei; Mei, Huiyang; Shao, Dadong; Wang, Xiangke

    2014-11-18

    The formation of mixed metal precipitates has been identified as a significant mechanism for the immobilization and elimination of heavy metal ions. Silicate is present in natural systems ubiquitously, which may interfere with metal uptake on the mineral surface and thereby influences the solubility of the precipitate. Herein, kinetic sorption and dissolution experiments combined with extended X-ray absorption fine structure spectroscopy (EXAFS) were performed to elucidate the effect of silicate on the formation of Ni precipitates at the γ-Al2O3 surfaces. The uptake of Ni on γ-Al2O3 decreased with increasing amounts of silicate coated onto the γ-Al2O3 surface. Results of EXAFS analyses suggested the formation of Ni-Al layered double hydroxide (LDH) phases. The surface coating of silicate on γ-Al2O3 reduced Al release and finally resulted in a high Ni:Al ratio due to a lower extent of Al substitution into the precipitates. The presence of silicate prevented the growth of the precipitates and led to the formation of less stable Ni-Al LDH. The influence of silicate on the precipitate formation provided the evidence for the growth relationship between the precipitate and mineral substrate in the real environment. Increased rates of proton-promoted dissolution of Ni surface precipitates were mainly attributed to higher Ni:Al ratios in Ni-Al LDH precipitates formed in the presence of silicate. PMID:25339547

  8. Tribological properties of thermally sprayed TiAl-Al2O3 composite coating

    NASA Astrophysics Data System (ADS)

    Salman, A.; Gabbitas, B.; Li, J.; Zhang, D.

    2009-08-01

    The use of thermal spray coatings provides protection to the surfaces operating in severe environments. The main goal of the current work is to investigate the possibility of using a high velocity oxy fuel (HVOF) thermally sprayed wear resistant TiAl/Al2O3 coating on tool steel (H13) which is used for making dies for aluminium high pressure die casting. A feedstock of TiAl/Al2O3 composite powder was produced from a mixture of Al and TiO2 powders by high energy mechanical milling, followed by a thermal reaction process. The feedstock was then thermally sprayed using a high velocity oxy-fuel (HVOF) technique onto H13 steel substrates to produce a composite coating. The present study describes and compares the tribological properties such as friction and sliding wear rate of the coating both at room and high temperature (700°C). The results showed that the composite coating has lower wear rate at high temperature (700°C) than the uncoated H13 sample. At Room temperature without using lubricant there is no much significant difference between the wear rate of the coated and uncoated samples. The experimental results showed that the composite coating has great potential for high temperature application due to its lower wear rate at high temperature in comparison with the uncoated sample at the same temperature. The composite coating was characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD). This paper reports the experimental observations and discusses the wear resistance performance of the coatings at room and high temperatures.

  9. Assessment of the Heavy Metals in Al Asfar Lake, Al-Hassa, Saudi Arabia.

    PubMed

    Hussein, Adel H A; El Mahmoudi, Ahmed S; Al Naeem, Ahmed A

    2016-02-01

    Al Asfar Lake is a shallow wetland and habitat for wildlife and birds in a desert environment. The water of this lake is originated from the drainage water collected by earthen drainage network and discharged into the lake. The purpose of this study was to assess physico- chemical characteristics and some of heavy metals in Al Asfar lake water. The studied parameters are iron, manganese, copper, zinc, cadmium, chromium, lead, pH, electrical conductivity, and nitrate. Forty-five surface water samples were collected in March 2013. The results revealed that the pH ranged from 7.33 to 8.67, electrical conductivity ranged from 8.28 to 11.34 dS/m, and NO(3)(-) ranged from 0.84 to 2.29 mg/L. In addition, heavy metals concentrations in water were found in the following order: Fe > Mn > Cu > Zn > Cd > Cr = Pb. The mean concentrations of heavy metals in surface water of Al Asfar lake ranged from 0.027 to 0.159 ppm, 0.007 to 0.142 ppm, 0.005 to 0.017 ppm, 0.005 to 0.066 ppm, 0.001 to 0.033 ppm, 0 ppm, and 0 ppm for iron, manganese, copper, zinc, cadmium, chromium, and lead, respectively. Moreover, pH, NO(3)(-), Fe, Mn, and Zn concentrations in the surface water of Al Asfar Lake were found to be within the international permissible limits. On the other hand, Cu and Cd concentrations exceeded the international permissible limits. The high level of some parameters of the measured heavy metals could be attributed to the contamination of Al Asfar Lake with discharge water enriched with chemical fertilizers in addition to domestic and industrial effluents. PMID:26803101

  10. The role of Al-goethites on arsenate mobility.

    PubMed

    Silva, Juscimar; Mello, Jaime W V; Gasparon, Massimo; Abrahão, Walter A P; Ciminelli, Virgínia S T; Jong, Tony

    2010-11-01

    The geochemical fates of Fe and As are so closely correlated that methods of As removal from contaminated water are in general based on the high affinity of this metalloid for Fe (hydr)oxides. Dissimilatory Fe reducing bacteria, however, play a fundamental role in catalysing the redox transformations that ultimately control the mobility of As in anoxic environments. The potential of Al-goethites in adsorbing As(V) compared with hematite, goethite, ferrihydrite, and gibbsite, and the stability of As retained by the Fe compounds under anoxic conditions were investigated in this study. The (hydr)oxides were synthesised, and adsorption isotherms and As(V) adsorption maxima at different pH were measured. Arsenic loaded samples were anaerobically incubated in the presence of Shewanella putrefaciens, and periodically sampled to evaluate the contents of soluble As and Fe. The As(V) adsorption maxima decreased in the following order: Fh > AlGt(13) > AlGt(20) > AlGt(23) > Gb > Hm > Gt. In terms of surface area, Gb, Gt, and Hm showed higher As(V) loading capacity than Fh, suggesting available reactive sites not fully occupied by arsenate on Fh. The same hypothesis can be considered for Al-goethites, as they showed even lower arsenate loading capacity per surface area. The presence of structural Al in the goethites enhanced considerably the As uptake capacity and stability under reducing conditions. Therefore, the Al-goethites showed good potential as adsorbents to remove As from water. S. putrefaciens cells were able to utilise both noncrystalline and crystalline Fe (hydr)oxides as electron acceptors, releasing As into solution. Al-goethites showed a decrease in Fe and As mobilisation as structural Al increased. PMID:20638700

  11. In memory of Al Cameron

    NASA Astrophysics Data System (ADS)

    Cowan, John; Truran, James W.

    Al Cameron, who died recently (October 3, 2005) at 80, was one of the giants in astrophysics. His insights were profound and his interests were wide-ranging. Originally trained as a nuclear physicist, he made major contributions in a number of fields, including nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, and the origin of the Solar System and the Moon. In 1957, Cameron and, independently, Burbidge, Burbidge, Fowler and Hoyle, wrote seminal papers on nuclear astrophysics. Most of our current ideas concerning ele- ment formation in stars have followed from those two pioneering and historical works. Al also made many contributions in the field of Solar System physics. Particularly noteworthy in this regard was Cameron's work on the formation of the Moon. Al was also a good friend and mentor of young people. Al Cameron will be missed by many in the community both for his scientific contributions and for his friendship.

  12. Reply to Gopalswamy et al.

    NASA Technical Reports Server (NTRS)

    Cane, H. V.; Richardson, I. G.

    2003-01-01

    The comment of Gopalswamy et al. (thereafter GMY) relates to a letter discussing coronal mass ejections (CMEs), interplanetary ejecta and geomagnetic storms. GMY contend that Cane et al. incorrectly identified ejecta (interplanetary CMEs) and hypothesize that this is because Cane et al. fail to understand how to separate ejecta from "shock sheaths" when interpreting solar wind and energetic particle data sets. They (GMY) are wrong be cause the relevant section of the paper was concerned with the propagation time to 1 AU of any potentially geoeffective structures caused by CMEs, i.e. upstream compression regions with or without shocks, or ejecta. In other words, the travel times used by Cane et al. were purposefully and deliberately distinct from ejecta travel times (except for those slow ejecta, approx. 30% of their events, which generated no upstream features), and no error in identification was involved. The confusion of GMY stems from the description did not characterize the observations sufficiently clearly.

  13. Comparing the Thermodynamic Behaviour of Al(1)+ZrO2(s) to Al(1)+Al2O3(s)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2004-01-01

    In an effort to better determine the thermodynamic properties of Al(g) and Al2O(g). the vapor in equilibrium with Al(l)+ZrO2(s) was compared to the vapor in equilibrium with Al(l)+Al2O3(s) over temperature range 1197-to-1509K. The comparison was made directly by Knudsen effusion-cell mass spectrometry with an instrument configured for a multiple effusion-cell vapor source (multi-cell KEMS). Second law enthalpies of vaporization of Al(g) and Al2O(g) together with activity measurements show that Al(l)+ZrO2(s) is thermodynamically equivalent to Al(l)+Al2O3(s), indicating Al(l) remained pure and Al2O3(s) was present in the ZrO2-cell. Subsequent observation of the Al(l)/ZrO2 and vapor/ZrO2 interfaces revealed a thin Al2O3-layer had formed, separating the ZrO2-cell from Al(l) and Al(g)+Al2O(g), effectively transforming it into an Al2O3 effusion-cell. This behavior agrees with recent observations made for Beta-NiAl(Pt) alloys measured in ZrO2 effusion-cell.

  14. Corrosion Behavior of Al-Al3Ni and Al-Al2Cu Functionally Graded Materials Fabricated by a Centrifugal Method

    NASA Astrophysics Data System (ADS)

    Noda, Kazuhiko; Miyahara, Keita; Watanabe, Yoshimi

    2008-02-01

    Intermetallic compounds, such as Al3Ni and Al2Cu, are effective for enhancing the mechanical properties of an alloy. Al-Al3Ni and Al-Al2Cu functionally graded materials (FGMs) might be attractive materials for advanced materials. Al-Al3Ni and Al-Al2Cu FGMs were fabricated by a centrifugal method; the centrifugal method is an extremely effective method for fabricating FGMs. Al-Al3Ni and Al-Al2Cu FGMs that had a graded distribution of intermetallic compounds could be produced by this in-situ centrifugal method. Particle size, particle shape and the distribution of intermetallic compounds were controlled by varying the content of the alloy element (Ni, Cu) in the master alloy, the cooling rate in casting and the gravity number. The casting mechanism is explained in terms of the microstructures of the Al-Al3Ni and Al-Al2Cu FGMs fabricated by this method. The corrosion behavior of the FGMs was investigated by electrochemical analysis. Polarization curves of the FGMs in a borate solution were measured by a potentiodynamic method. The presence of Al2Cu exerted a larger effect on the corrosion behavior of the FGMs than Al3Ni. Analysis of the polarization curve parameters was effective for evaluating the corrosion resistance of the FGMs.

  15. Hydrogen environment embrittlement.

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1972-01-01

    Hydrogen embrittlement is classified into three types: internal reversible hydrogen embrittlement, hydrogen reaction embrittlement, and hydrogen environment embrittlement. Characteristics of and materials embrittled by these types of hydrogen embrittlement are discussed. Hydrogen environment embrittlement is reviewed in detail. Factors involved in standardizing test methods for detecting the occurrence of and evaluating the severity of hydrogen environment embrittlement are considered. The effects of test technique, hydrogen pressure, purity, strain rate, stress concentration factor, and test temperature are discussed.

  16. Environment resistant windows for space greenhouses

    NASA Astrophysics Data System (ADS)

    Gan, B. K.; Kondyurin, A.; Bilek, M.; Latella, B. A.

    One of the ways of providing a self-sustainable environment in space is to provide food and life support systems through bio-regenerative power i e a greenhouse It is an essential structure because it provides oxygen and food in a controlled environment The windows and frames of a greenhouse are generally made from glass or polymer panels which allow sunlight to enter Polymers are useful because they are lightweight transparent corrosion resistant and inexpensive However windows which are made from polymeric materials or polymer-based composites suffer from accelerated erosion due to the presence of atomic oxygen in space environment A metal oxide deposited on the surface of the polymer will aid in the resistance of these polymers to chemical attack as well as improving surface hardness and wear resistance characteristics In this study we modified the surfaces of polycarbonate PC by deposition and implantation of thin and transparent aluminium oxide Al 2 O 3 coatings The Al 2 O 3 plasma was produced using a cathodic arc deposition system with a combination of plasma immersion ion implantation PIII The coatings were then tested for resistance to atomic oxygen environment These were carried out by monitoring the mass loss of the deposited samples exposed to an rf oxygen plasma The morphology and optical properties of the coatings before and after exposure to oxygen plasma were then examined using electron microscopy profilometry and ellipsometry Mechanical properties and adhesion characteristics of the coatings

  17. Hydrogen environment embrittlement

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1972-01-01

    Hydrogen embrittlement is classified into three types: internal reversible hydrogen embrittlement, hydrogen reaction embrittlement, and hydrogen environment embrittlement. Characteristics of and materials embrittled by these types of hydrogen embrittlement are discussed. Hydrogen environment embrittlement is reviewed in detail. Factors involved in standardizing test methods for detecting the occurrence of and evaluating the severity of hydrogen environment embrittlement are considered. The effect of test technique, hydrogen pressure, purity, strain rate, stress concentration factor, and test temperature are discussed. Additional research is required to determine whether hydrogen environment embrittlement and internal reversible hydrogen embrittlement are similar or distinct types of embrittlement.

  18. General aviation environment

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The background, development, and relationship, among economic factors, airworthiness, costs, and environment protection are examined. Government regulations for airports, air agencies, aircraft, and airmen are reviewed.

  19. Mining the Home Environment

    PubMed Central

    Cook, Diane J.; Krishnan, Narayanan

    2014-01-01

    Individuals spend a majority of their time in their home or workplace and for many, these places are our sanctuaries. As society and technology advance there is a growing interest in improving the intelligence of the environments in which we live and work. By filling home environments with sensors and collecting data during daily routines, researchers can gain insights on human daily behavior and the impact of behavior on the residents and their environments. In this article we provide an overview of the data mining opportunities and challenges that smart environments provide for researchers and offer some suggestions for future work in this area. PMID:25506128

  20. Microbiology & Toxicology: Space Environment

    NASA Video Gallery

    One key aspect in maintaining crew health and performance during spaceflight missions is the provision of a habitable environment with acceptably low concentrations of microbiological and toxicolog...

  1. CarbAl Heat Transfer Material

    NASA Technical Reports Server (NTRS)

    Fink, Richard

    2015-01-01

    The increasing use of power electronics, such as high-current semiconductor devices and modules, within space vehicles is driving the need to develop specialty thermal management materials in both the packaging of these discrete devices and the packaging of modules consisting of these device arrays. Developed by Applied Nanotech, Inc. (ANI), CarbAl heat transfer material is uniquely characterized by its low density, high thermal diffusivity, and high thermal conductivity. Its coefficient of thermal expansion (CTE) is similar to most power electronic materials, making it an effective base plate substrate for state-of-the-art silicon carbide (SiC) super junction transistors. The material currently is being used to optimize hybrid vehicle inverter packaging. Adapting CarbAl-based substrates to space applications was a major focus of the SBIR project work. In Phase I, ANI completed modeling and experimentation to validate its deployment in a space environment. Key parameters related to cryogenic temperature scaling of CTE, thermal conductivity, and mechanical strength. In Phase II, the company concentrated on improving heat sinks and thermally conductive circuit boards for power electronic applications.

  2. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    NASA Astrophysics Data System (ADS)

    Yadav, S. K.; Wang, J.; Liu, X.-Y.

    2016-06-01

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. The formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamically driven process.

  3. High Density Sliding at Ta/Al and Al/Al Interfaces

    SciTech Connect

    Hammerberg, J. E.; Germann, T. C.; Ravelo, R.

    2006-07-28

    We present 3D-nonequilibrium molecular dynamics results for the velocity dependence of the frictional force at smooth sliding interfaces for Ta and Al single crystals. For Ta/Al we consider Al(100)/Ta(100) and Al(111)/Ta(110) interfaces sliding along [001] and [11(bar sign)0]fcc /[001]bcc respectively. These are compared with Al(111)/Al(100) interfaces at the same loads, corresponding to a pressure of 15 GPa. Both interfacial pairs show similar behavior in the velocity dependence of the frictional force: a low velocity regime with an increasing frictional force followed by a strain induced transformation regime at velocities above approximately 1/10 the transverse sound speed, followed by a fluidized interface at high velocities. For both interfacial pairs, the high velocity dependence of the frictional force exhibits power law behavior, Ft {proportional_to} v-{beta} with {beta}=3/4. We discuss the structural changes that influence dissipation in each of these regimes.

  4. Accessing (Ba1-xSrx)Al2Si2O8:Eu Phosphors for Solid State White Lighting via Microwave-assisted Preparation: Tuning Emission Color by Coordination Environment

    SciTech Connect

    Brgoch, Jakoah; Klob, Simon D.; Denault, Kristin A.; Seshadri, Ram

    2014-07-15

    The preparation of Eu2+-substituted barium aluminum silicates is achieved using a rapid microwave-assisted preparation. The phase evolution of two BaAl2Si2O8:Eu2+ polymorphs, the higher temperature hexagonal phase (hexacelsian), and the lower temperature monoclinic phase (celsian), is explored by varying the ramp time and soak time. This preparation method significantly reduces the reaction time needed to form these phases compared to conventional solid state routes. The luminescent properties of the two phases are identified under UV excitation with the hexagonal phase emitting in the UV region (λem = 372 nm) and the monoclinic phase emitting in the blue region (λem = 438 nm). The differences in optical properties of the two polymorphs are correlated to the coordination number and arrangement of the alkali earth site. The optical properties of the monoclinic phase can be further tuned through the substitution of Sr2+, forming the solid solution (Ba1–xSrx)Al2Si2O8:Eu2+. Changes in the crystal structure due to Sr2+ substitution produce a surprising blue-shift in the emission spectrum, which is explained by a greater dispersion of bond lengths in the (Ba/Sr)–O polyhedra. The entire monoclinic solid solution exhibits excellent quantum yields of nearly 90 %, owing to the structural rigidity provided by the highly connected tetrahedral network.

  5. THERMAL ENVIRONMENT AND LEARNING.

    ERIC Educational Resources Information Center

    LANE, W.R.

    RESEARCH ON THERMAL ENVIRONMENT IN SCHOOLS IS SUMMARIZED AND THE STATUS OF "THERMAL ENVIRONMENT AND LEARNING" RESEARCH COMPLETED AND/OR UNDERWAY IN THE IOWA CENTER FOR RESEARCH IN SCHOOL ADMINISTRATION IS REPORTED. RESULTS ARE--(1) CHILDREN DID LEARN BETTER UNDER MODEL THERMAL CONDITIONS, (2) TEACHERS MUST BECOME MORE AWARE OF THERMAL CONDITIONS,…

  6. Open Access Learning Environments

    ERIC Educational Resources Information Center

    Mentor, Kenneth

    2007-01-01

    Educational institutions are increasingly adopting "closed" learning environments that hide learning materials in password-protected areas. While this may be a logical solution to a range of problems, much is lost in this mode of course delivery. Although there are logical reasons for moving toward closed environments, we may be erring…

  7. Energy-Environment Opinionnaire.

    ERIC Educational Resources Information Center

    Wert, Jonathan M.

    This questionnaire is designed to assess the opinions of students and teachers of educational institutions and citizens about energy and the environment. It is composed of 85 energy and environment oriented statements about which the examinee gives an opinion. Choices provided on the answer sheet given are strongly agree, mildly agree, not sure or…

  8. Healthful School Environment.

    ERIC Educational Resources Information Center

    Wilson, Charles C., Ed.; Wilson, Elizabeth Avery, Ed.

    A broad range of topics deals with the development, maintenance, and full utilization of a healthful school environment, encompassing such areas as--(1) school organizations which affect the student environment, (2) accident prevention, (3) the criteria for healthful food services, (4) physical education and the necessary athletic facilities, (5)…

  9. An Engaging Learning Environment

    ERIC Educational Resources Information Center

    Krueger, Tom

    2010-01-01

    The author believes that a stimulating learning environment can offer benefits to the general classroom conduct of young people through the different charts displayed in his classroom. Students see the teacher taking pride in their shared working environment and wall or table graffiti. He mentions that he does not only care for his students'…

  10. Forest Environment Learning Experiences.

    ERIC Educational Resources Information Center

    Szuhy, Donna L. T.; Shepard, Clint L.

    Environmental education, as a teaching methodology, is appropriate for all subject areas and environments. Two teaching approaches are presented with the 13 activities in this booklet serving as examples of their application to the forest environment and different disciplines. The first approach is based upon the understanding that learners retain…

  11. Space and Atmospheric Environments

    NASA Technical Reports Server (NTRS)

    Barth, Janet L.; Day, John H. (Technical Monitor)

    2002-01-01

    This viewgraph presentation provides information on space environments and the protection of materials and structures from their harsh conditions. Space environments are complex, and the complexity of spacecraft systems is increasing. Design accommodation must be realistic. Environmental problems can be limited at low cost relative to spacecraft cost.

  12. Outdoor Environments. Beginnings Workshop.

    ERIC Educational Resources Information Center

    Child Care Information Exchange, 2003

    2003-01-01

    Presents seven articles on outdoor play environments: "Are We Losing Ground?" (Greenman); "Designing and Creating Natural Play Environments for Young Children" (Keeler); "Adventure Playgrounds and Outdoor Safety Issues" (McGinnis); "Trust, the Earth and Children: Birth to Three" (Young); "Outdoor Magic for Family Child Care Providers" (Osborn); "A…

  13. Population and Environment

    EPA Science Inventory

    The concept of 'protection' is possible only before something is lost, however, development of the built environment to meet human needs also compromises the environmental systems that sustain human life. Because maintaining an environment that is able to sustain human life re...

  14. Understanding Our Environment: Planet.

    ERIC Educational Resources Information Center

    Callister, Jeffrey C.; And Others

    Part of the Understanding Our Environment project that is designed to engage students in investigating specific environmental problems through concrete activities and direct experience, this unit places Earth in the context of its environment-the Universe-then focuses on Earth as seen from satellites. Students analyze patterns formed by the…

  15. Creative Display & Environment.

    ERIC Educational Resources Information Center

    Jackson, Margaret

    This book builds a case for the importance of the learning environment as functional, inviting, and enabling for children. Chapter 1, "A pressing need: why display and environment for learning matter," introduces the book, discusses a strategy for staff development, suggests points to consider when surveying the school, and talks about involving…

  16. Managing School Environments.

    ERIC Educational Resources Information Center

    Berry, Michael A.

    Asserting that successfully managing a school environment is a necessary and essential educational investment, this paper details common problems with school environments and how to address them. These include environmental awareness training, moisture and water management, effective ventilation, mold removal, and cleaning and restoration…

  17. Building Informatics Environment

    2008-06-02

    The Building Informatics Environment is a modeling environment based on the Modelica language. The environment allows users to create a computer model of a building and its energy systems with various time scales and physical resolutions. The environment can be used for rapid development of, e.g., demand controls algorithms, new HVAC system solutions and new operational strategies (controls, fault detection and diagnostics). Models for building energy and control systems are made available in the environment.more » The models can be used as provided, or they can be changed and/or linked with each other in order to model the effects that a particular user is interested in.« less

  18. Population and Environment

    PubMed Central

    de Sherbinin, Alex; Carr, David; Cassels, Susan; Jiang, Leiwen

    2009-01-01

    The interactions between human population dynamics and the environment have often been viewed mechanistically. This review elucidates the complexities and contextual specificities of population-environment relationships in a number of domains. It explores the ways in which demographers and other social scientists have sought to understand the relationships among a full range of population dynamics (e.g., population size, growth, density, age and sex composition, migration, urbanization, vital rates) and environmental changes. The chapter briefly reviews a number of the theories for understanding population and the environment and then proceeds to provide a state-of-the-art review of studies that have examined population dynamics and their relationship to five environmental issue areas. The review concludes by relating population-environment research to emerging work on human-environment systems. PMID:20011237

  19. Genesis Radiation Environment

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Altstatt, Richard L.; Skipworth, William C.

    2007-01-01

    The Genesis spacecraft launched on 8 August 2001 sampled solar wind environments at L1 from 2001 to 2004. After the Science Capsule door was opened, numerous foils and samples were exposed to the various solar wind environments during periods including slow solar wind from the streamer belts, fast solar wind flows from coronal holes, and coronal mass ejections. The Survey and Examination of Eroded Returned Surfaces (SEERS) program led by NASA's Space Environments and Effects program had initiated access for the space materials community to the remaining Science Capsule hardware after the science samples had been removed for evaluation of materials exposure to the space environment. This presentation will describe the process used to generate a reference radiation Genesis Radiation Environment developed for the SEERS program for use by the materials science community in their analyses of the Genesis hardware.

  20. Plasmonic Fano resonances in compositional heterogenous Al- Au nanorod dimers

    NASA Astrophysics Data System (ADS)

    Wu, Botao; Xue, Yingxian; Ma, Qiang; Ding, Chengjie; Rong, Youying; Liu, Yan; Chen, Lingxiao; Wu, E.; Zeng, Heping

    2016-01-01

    We have investigated theoretically the plasmon resonance coupling in compositional heterogenous Al-Au nanorod dimers organized in a close proximity by end-to-end. It has been proved that the destructive interference between the bright dipole mode from Al nanorod and the dark quadrupole mode from Au nanorod nearby results in the appearance of apparent Fano resonance in the extinction spectra. The Fano resonance response on the structural dimension modifications in the proposed nanorod dimers have been estimated and determined. The Al-Au heterogeneous nanorod dimer shows a high sensitivity to the surrounding environment with a local surface plasmon resonance figure of merit of 7.6, which enables its promising applications in plasmonic sensing and detection.

  1. NMR characteristics in noncentrosymmetric Mo3Al2C

    NASA Astrophysics Data System (ADS)

    Kuo, C. N.; Liu, H. F.; Lue, C. S.

    2012-02-01

    We present an extensive study of the noncentrosymmetric superconductor Mo3Al2C using 27Al nuclear magnetic resonance (NMR) spectroscopy. The NMR line shapes, Knight shifts, as well as spin-lattice relaxation rates in both superconducting and normal states have been identified. In the superconducting phase, the results of the Knight shift and relaxation rate signify the existence of finite density of states, attributed to the strong antisymmetric spin-orbital coupling effect enhanced by intrinsic defects. In the normal state, peculiar changes such as the broadening of the NMR linewidth and the distinct drop of the Knight shift were discerned across a characteristic temperature of T*≃196 K. Moreover, the magnitude of 1/T1T decreases markedly and develops pseudogaplike behavior below T*. We associated these anomalous features with distortions near the Al sites toward a lower symmetric structural environment, leading to the modification of electronic structures around Fermi surfaces.

  2. Photosynthetic microorganisms in cold environments

    NASA Astrophysics Data System (ADS)

    Kviderova, Jana; Hajek, Josef; Elster, Josef; Bartak, Milos; Vaczi, Peter; Nedbalova, Linda

    The polar regions are considered as a model of extraterrestrial ecosystems. Depending on the average temperature, temperature variation and water availability, these conditions could be used as a model of Mars or Europa (e.g. (Elster and Benson, 2004). Two cases are presented: 1) Stable temperature and water availability The environment of cryosestic communities, i.e. organisms living in snow, is characterized by very stable temperature; the diurnal variations do not exceed 1 -2 ° C (Kváderová, 2010) and a are not usually exposed to freeze/thaw. Water is not usually limiting since the water content could reach up to 54 % (Nedbalová et al., 2008). The windblown sediments are important a source of nutrient and could provide protection against the excess of radiation. The nutrient concentrations in the snow are low are depleted rapidly when massive algal blooms forms. Such environment could be found near Mars polar caps or in Europa ice cover. The snow algae are the most important primary producers in snow. Their adaptation strategy is dependent on the developmental stages; the motile stages avoid the harsh conditions (e.g. high light) and sessile stages acclimatize to actual conditions. The main genera Chlamydomonas and Chloromonas (both Chlorophyta) are psychrophilic. Their growth optimum temperature is lower than 15 ° C and their growth is inhibited at temperatures above 20 ° C. 2) Unstable temperature and water availability The deglaciated surfaces, inhabited by lichen communities, are typical by variation in temper-ature and moisture. The temperature could range several tens ° C within a short time and the water availability is usually very limited. Due to temperature variation, the lichens are subjected to many freeze/thaw cycles. Such environments could be found in Martian deserts. The lichens are symbotic organisms composed of a mycobiont (heterotrophic fungi) and photo-bionts (algae and/or cyanobacteria). Majority of lichens are dehydrated in the field

  3. High temperature, oxidation resistant noble metal-Al alloy thermocouple

    NASA Technical Reports Server (NTRS)

    Smialek, James L. (Inventor); Gedwill, Michael G. (Inventor)

    1994-01-01

    A thermocouple is disclosed. The thermocouple is comprised of an electropositive leg formed of a noble metal-Al alloy and an electronegative leg electrically joined to form a thermocouple junction. The thermocouple provides for accurate and reproducible measurement of high temperatures (600 - 1300 C) in inert, oxidizing or reducing environments, gases, or vacuum. Furthermore, the thermocouple circumvents the need for expensive, strategic precious metals such as rhodium as a constituent component. Selective oxidation of rhodium is also thereby precluded.

  4. Superconductivity in Al/Al2O3 interface

    NASA Astrophysics Data System (ADS)

    Palnichenko, A. V.; Vyaselev, O. M.; Mazilkin, A. A.; Khasanov, S. S.

    2016-06-01

    Metastable superconductivity at Tc ≈ 65 K has been observed in Al foil subjected to special oxidation process, according to the ac magnetic susceptibility and electrical resistance measurements. Comparison of the ac susceptibility and the dc magnetization measurements infers that the superconductivity arises within the interfacial granular layer formed during the oxidation process between metallic aluminum and its oxide.

  5. AlN/Fe/AlN nanostructures for magnetooptic magnetometry

    SciTech Connect

    Lišková-Jakubisová, E. Višňovský, Š.; Široký, P.; Hrabovský, D.; Pištora, J.

    2014-05-07

    AlN/Fe/AlN/Cu nanostructures with ultrathin Fe grown by sputtering on Si substrates are evaluated as probes for magnetooptical (MO) mapping of weak currents. They are considered for a laser wavelength of λ = 410 nm (3.02 eV) and operate at oblique light incidence angles, φ{sup (0)}, to enable detection of both in-plane and out-of-plane magnetization. Their performance is evaluated in terms of MO reflected wave electric field amplitudes. The maximal MO amplitudes in AlN/Fe/AlN/Cu are achieved by a proper choice of layer thicknesses. The nanostructures were characterized by MO polar Kerr effect at φ{sup (0)} ≈ 5° and longitudinal Kerr effect spectra (φ{sup (0)} = 45°) at photon energies between 1 and 5 eV. The nominal profiles were refined using a model-based analysis of the spectra. Closed form analytical expressions are provided, which are useful in the search for maximal MO amplitudes.

  6. Oxidation of Fe-Cr-Al and Fe-Cr-Al-Y Single Crystals

    NASA Astrophysics Data System (ADS)

    Grabke, H. J.; Siegers, M.; Tolpygo, V. K.

    1995-03-01

    Single crystal samples of the alloy Fe-20%Cr-5%Al with and without Y-doping were used to study the "reactive element" (RE) effect, which causes improved oxidation behaviour and formation of a protective Al2O3 layer on this alloy. The oxidation was followed by AES at 10-7 mbar O2 up to about 1000 °C. Most observations were peculiar for this low pO2 environment, but yttrium clearly favors the formation of Al-oxide and stabilizes it also under these conditions, probably by favoring its nucleation. The oxides formed are surface compounds of about monolayer thickness, not clearly related to bulk oxides. Furthermore, the morphologies of oxide scales were investigated by SEM, after oxidation at 1000°C for 100 h at 133 mbar O2. On Fe-Cr-Al the scale is strongly convoluted and tends to spalling, whereas the presence of Y leads to flat scales which are well adherent. This difference is explained by a change in growth mechanism. The tendency for separation of oxide and metal was highest for the samples with low energy metal surface, i.e. (100) and (110), the scale was better adherent on the (111) oriented surface and on the polycrystalline specimen, since in the latter cases the overall energy for scale/metal separation is higher. All observations, from the low and from the high pO2 experiments, are discussed in relation to the approximately ten mechanisms proposed in the literature for explanation of the RE effects.

  7. ALS - A unique design approach

    NASA Astrophysics Data System (ADS)

    Chamberlain, Roger A.

    1990-09-01

    An advanced launch system (ALS), which is intended to be flexible and to deliver a wide range of payloads at a reduced cost, is discussed. The ALS concept also features total quality management, modular subsystems, standardized interfaces, standardized missions, and off-line payload encapsulation. The technological improvements include manufacturing of dry structures, use of composite materials, adaptive guidance and control systems, and laser-initiated radar systems. The operational improvements range from paperless management, to rocket engine leak detection devices and automated ground operations.

  8. Standards Laboratory environments

    SciTech Connect

    Braudaway, D.W.

    1990-09-01

    Standards Laboratory environments need to be carefully selected to meet the specific mission of each laboratory. The mission of the laboratory depends on the specific work supported, the measurement disciplines required and the level of uncertainty required in the measurements. This document reproduces the contents of the Sandia National Laboratories Primary Standards Laboratory Memorandum Number 3B (PSLM-3B) which was issued on May 16, 1988, under the auspices of the Department of Energy, Albuquerque Operations Office, to guide the laboratories of the Nuclear Weapons Complex in selecting suitable environments. Because of both general interest and specific interest in Standards Laboratory environments this document is being issued in a more available form. The purpose of this document is to provide guidance in selection of laboratory environments suitable for standards maintenance and calibration operations. It is not intended to mandate a specific environment for a specific calibration but to direct selection of the environment and to offer suggestions on how to extend precision in an existing and/or achievable (practical) environment. Although this documents pertains specifically to standards laboratories, it can be applied to any laboratory requiring environmental control.

  9. Navigation in virtual environments

    NASA Astrophysics Data System (ADS)

    Arthur, Erik; Hancock, Peter A.; Telke, Susan

    1996-06-01

    Virtual environments show great promise in the area of training. ALthough such synthetic environments project homeomorphic physical representations of real- world layouts, it is not known how individuals develop models to match such environments. To evaluate this process, the present experiment examined the accuracy of triadic representations of objects having learned them previously under different conditions. The layout consisted of four different colored spheres arranged on a flat plane. These objects could be viewed in either a free navigation virtual environment condition (NAV) or a single body position virtual environment condition. The first condition allowed active exploration of the environment while the latter condition allowed the participant only a passive opportunity to observe form a single viewpoint. These viewing conditions were a between-subject variable with ten participants randomly assigned to each condition. Performance was assessed by the response latency to judge the accuracy of a layout of three objects over different rotations. Results showed linear increases in response latency as the rotation angle increased from the initial perspective in SBP condition. The NAV condition did not show a similar effect of rotation angle. These results suggest that the spatial knowledge acquisition from virtual environments through navigation is similar to actual navigation.

  10. Corrosion protection and galvanic corrosion prevention for 7075 Al and Ti-6Al-6V-2Sn alloys. Final report

    SciTech Connect

    Clay, F.A.

    1980-07-01

    Sulfuric-acid-anodized and electroless-nickel-plated 7075 aluminum alloy panels successfully passed 96 hours of salt spray testing when galvanically coupled to duplex-annealed Ti-6Al-6V-2Sn alloy panels. Adherent paint deposits were produced on the titanium alloy and electroless nickel surfaces using a wash primer, an epoxy primer, and a urethane paint coating. A painted part survived 35 cycles of alternating salt spray and hot and freezing environments without blistering. A low chloride cutting fluid was selected for production machining of Ti-6Al-6V-2Sn, based on chemical analysis and stress-corrosion tests. A cleaning process was developed to remove both titanium and aluminum cutting fluids. Modified wedge-opening-loading specimens were used to verify that no stress-corrosion cracking problems occurred with the duplex-annealed Ti-6Al-6V-2Sn alloy because of residual titanium or aluminum cutting fluids.

  11. Software development environment, appendix F

    NASA Technical Reports Server (NTRS)

    Riddle, W. E.

    1980-01-01

    The current status in the area of software development environments is assessed. The purposes of environments, the types of environments, the constituents of an environment, the issue of environment integration, and the problems which must be solved in preparing an environment are discussed. Some general maxims to guide near-term future work are proposed.

  12. Development and High Temperature Property Evaluation of Ni-Co-Cr-Al Composite Electroforms

    NASA Astrophysics Data System (ADS)

    Srivastava, Meenu; Siju; Balaraju, J. N.; Ravisankar, B.

    2015-05-01

    Ni-Co-Cr-Al composite electroforms were developed with cobalt content of 10 and 40 wt.%. Cr and Al nano-particles were suspended in sulphamate electrolyte and co-deposited in the Ni-Co matrices. The surface morphology was investigated using field emission scanning electron microscope and the composition analyzed by energy-dispersive x-ray analysis. The oxidation resistance of the electroforms was studied from 600 to 1000 °C. The weight gain of Ni-10 wt.%Co-Cr-Al was less (better oxidation resistance) compared to Ni-Cr-Al and Ni-40 wt.%Co-Cr-Al. The x-ray diffraction studies revealed that the oxidation product formed on the surface of Ni-Cr-Al and Ni-10 wt.%Co-Cr-Al consisted of NiO and Al2O3, while Ni-40 wt.%Co-Cr-Al comprised oxides such as NiCo2O4, CrO3, CoO, NiO, and Al2O3. The hot corrosion behavior was investigated in 75%Na2SO4 + 25%NaCl environment at 800 °C. It was found that the hot corrosion resistance of the composite coating improved with increase in cobalt content. The probable composition suitable for high-temperature applications was found to be Ni-10 wt.%Co-Cr-Al.

  13. Genetic Interactions with Prenatal Social Environment: Effects on Academic and Behavioral Outcomes. NBER Working Paper No. 16026

    ERIC Educational Resources Information Center

    Conley, Dalton; Rauscher, Emily

    2010-01-01

    Caspi et al. (2002, 2003), Guo et al. (2008a), and Pescosolido et al. (2008) all claim to have demonstrated allele-by-environment interactions, but in all cases environmental influences are potentially endogenous to the unmeasured genetic characteristics of the subjects and their families. Thus, gene-gene interactions cannot be ruled out as an…

  14. Dynamic Modeling of ALS Systems

    NASA Technical Reports Server (NTRS)

    Jones, Harry

    2002-01-01

    The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

  15. Environments for Plants

    ERIC Educational Resources Information Center

    Mier, Robert; Poling, Donald

    1970-01-01

    Reviews some recent research on the effects of environment on plant growth. Also offers some how-to-do-it information on building low-cost, easy-to-construct greenhouses and growth chambers for school use. Bibliography. (LC)

  16. Extreme environments and exobiology

    NASA Technical Reports Server (NTRS)

    Friedmann, E. I.

    1993-01-01

    Ecological research on extreme environments can be applied to exobiological problems such as the question of life on Mars. If life forms (fossil or extant) are found on Mars, their study will help to solve fundamental questions about the nature of life on Earth. Extreme environments that are beyond the range of adaptability of their inhabitants are defined as "absolute extreme". Such environments can serve as terrestrial models for the last stages of life in the history of Mars, when the surface cooled down and atmosphere and water disappeared. The cryptoendolithic microbial community in porous rocks of the Ross Desert in Antarctica and the microbial mats at the bottom of frozen Antarctic lakes are such examples. The microbial communities of Siberian permafrost show that, in frozen but stable communities, long-term survival is possible. In the context of terraforming Mars, selected microorganisms isolated from absolute extreme environments are considered for use in creation of a biological carbon cycle.

  17. Visualization Design Environment

    SciTech Connect

    Pomplun, A.R.; Templet, G.J.; Jortner, J.N.; Friesen, J.A.; Schwegel, J.; Hughes, K.R.

    1999-02-01

    Improvements in the performance and capabilities of computer software and hardware system, combined with advances in Internet technologies, have spurred innovative developments in the area of modeling, simulation and visualization. These developments combine to make it possible to create an environment where engineers can design, prototype, analyze, and visualize components in virtual space, saving the time and expenses incurred during numerous design and prototyping iterations. The Visualization Design Centers located at Sandia National Laboratories are facilities built specifically to promote the ''design by team'' concept. This report focuses on designing, developing and deploying this environment by detailing the design of the facility, software infrastructure and hardware systems that comprise this new visualization design environment and describes case studies that document successful application of this environment.

  18. Man and His Environment

    ERIC Educational Resources Information Center

    Coale, Ansley J.

    1970-01-01

    Discusses economic factors as the essential causes of world environment deterioration. Presents case for critical and prompt action in prevention of natural resource exhaustion and pollution, particularly by means of replacement level, population control, and consequent economic organization. (JM)

  19. Environment and World Tourism.

    ERIC Educational Resources Information Center

    Larre, Dominique

    1979-01-01

    Tourism can create significant impacts on both the social and natural environment; however, many nations have avoided the negative impacts. Consideration of the effects of tourism should be part of national policy toward the tourist industry. (RE)

  20. Hypoxia in the changing marine environment

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Cowie, G.; Naqvi, S. W. A.

    2013-03-01

    The predicted future of the global marine environment, as a combined result of forcing due to climate change (e.g. warming and acidification) and other anthropogenic perturbation (e.g. eutrophication), presents a challenge to the sustainability of ecosystems from tropics to high latitudes. Among the various associated phenomena of ecosystem deterioration, hypoxia can cause serious problems in coastal areas as well as oxygen minimum zones in the open ocean (Diaz and Rosenberg 2008 Science 321 926-9, Stramma et al 2008 Science 320 655-8). The negative impacts of hypoxia include changes in populations of marine organisms, such as large-scale mortality and behavioral responses, as well as variations of species distributions, biodiversity, physiological stress, and other sub-lethal effects (e.g. growth and reproduction). Social and economic activities that are related to services provided by the marine ecosystems, such as tourism and fisheries, can be negatively affected by the aesthetic outcomes as well as perceived or real impacts on seafood quality (STAP 2011 (Washington, DC: Global Environment Facility) p 88). Moreover, low oxygen concentration in marine waters can have considerable feedbacks to other compartments of the Earth system, like the emission of greenhouse gases to the atmosphere, and can affect the global biogeochemical cycles of nutrients and trace elements. It is of critical importance to prediction and adaptation strategies that the key processes of hypoxia in marine environments be precisely determined and understood (cf Zhang et al 2010 Biogeosciences 7 1-24).

  1. Obesogenic Environments in Youth

    PubMed Central

    Boone-Heinonen, Janne; Gordon-Larsen, Penny

    2012-01-01

    To effectively prevent and reduce childhood obesity through healthy community design, it is essential to understand which neighborhood environment features influence weight gain in various age groups. However, most neighborhood environment research is cross-sectional, focuses on adults, and is often carried out in small, nongeneralizable geographic areas. Thus, there is a great need for longitudinal neighborhood environment research in diverse populations across the lifecycle. This paper describes: (1) insights and challenges of longitudinal neighborhood environment research and (2) advancements and remaining gaps in measurement and study design that examine individuals and neighborhoods within the context of the broader community. Literature-based research and findings from the “Obesity and Neighborhood Environment Database” (ONEdata), a unique longitudinal GIS that is spatially and temporally linked to data in the National Longitudinal Study of Adolescent Health (N=20,745), provide examples of current limitations in this area of research. Findings suggest a need for longitudinal methodologic advancements to better control for dynamic sources of bias, investigate and capture appropriate temporal frameworks, and address complex residential location processes within families. Development of improved neighborhood environment measures that capture relevant geographic areas within complex communities and investigation of differences across urbanicity and sociodemographic composition are needed. Further longitudinal research is needed to identify, refine, and evaluate national and local policies to most effectively reduce childhood obesity. PMID:22516502

  2. Measuring Physical Activity Environments

    PubMed Central

    Sallis, James F.

    2010-01-01

    Physical activity is usually done in specific types of places, referred to as physical activity environments. These often include parks, trails, fitness centers, schools, and streets. In recent years, scientific interest has increased notably in measuring physical activity environments. The present paper provides an historical overview of the contributions of the health, planning, and leisure studies fields to the development of contemporary measures. The emphasis is on attributes of the built environment that can be affected by policies to contribute to the promotion of physical activity. Researchers from health fields assessed a wide variety of built environment variables expected to be related to recreational physical activity. Settings of interest were schools, workplaces, and recreation facilities, and most early measures used direct observation methods with demonstrated inter-observer reliability. Investigators from the city planning field evaluated aspects of community design expected to be related to people’s ability to walk from homes to destinations. GIS was used to assess walkability defined by the 3Ds of residential density, land-use diversity, and pedestrian-oriented designs. Evaluating measures for reliability or validity was rarely done in the planning-related fields. Researchers in the leisure studies and recreation fields studied mainly people’s use of leisure time rather than physical characteristics of parks and other recreation facilities. Although few measures of physical activity environments were developed, measures of aesthetic qualities are available. Each of these fields made unique contributions to the contemporary methods used to assess physical activity environments. PMID:19285214

  3. Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    2009-01-01

    In this paper, the effect of nanoparticles Al2O3 and Al3-X compounds (X = Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their low cost, chemical stability and low diffusions rates in aluminum at high temperatures. The strengthening mechanism at high temperature for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. For Al2O3 nanoparticles, the test samples were prepared from special Al2O3 preforms, which were produced using ceramic injection molding process and then pressure infiltrated by molten aluminum. In another method, Al2O3 nanoparticles can also be homogeneously mixed with fine aluminum powder and consolidated into test samples through hot pressing and sintering. With the Al3-X nanoparticles, the test samples are produced as precipitates from in-situ reactions with molten aluminum using conventional permanent mold or die casting techniques. It is found that cast aluminum alloy using nanoparticles Al3-X is the most cost effective method to produce high strength aluminum alloys for high temperature applications in comparison to nanoparticles Al2O3. Furthermore, significant mechanical properties retention in high temperature environment could be achieved with Al3-X nanoparticles, resulting in tensile strength of nearly 3 times higher than most 300- series conventional cast aluminum alloys tested at 600 F.

  4. Large rectification magnetoresistance in nonmagnetic Al/Ge/Al heterojunctions

    NASA Astrophysics Data System (ADS)

    Zhang, Kun; Li, Huan-Huan; Grünberg, Peter; Li, Qiang; Ye, Sheng-Tao; Tian, Yu-Feng; Yan, Shi-Shen; Lin, Zhao-Jun; Kang, Shi-Shou; Chen, Yan-Xue; Liu, Guo-Lei; Mei, Liang-Mo

    2015-09-01

    Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can generate a significant direct-current voltage, and this rectification voltage strongly varies with the external magnetic field. We find that the rectification magnetoresistance in Al/Ge Schottky heterojunctions is as large as 250% at room temperature, which is greatly enhanced as compared with the conventional magnetoresistance of 70%. The findings of rectification magnetoresistance open the way to the new nonmagnetic Ge-based spintronics devices of large rectification magnetoresistance at ambient temperature under the alternating-current due to the simultaneous implementation of the rectification and magnetoresistance in the same devices.

  5. Study on biodegradation of the second phase Mg17Al12 in Mg-Al-Zn alloys: in vitro experiment and thermodynamic calculation.

    PubMed

    Liu, Chen; Yang, Huazhe; Wan, Peng; Wang, Kehong; Tan, Lili; Yang, Ke

    2014-02-01

    The in vitro biodegradation behavior of Mg17Al12 as a second phase in Mg-Al-Zn alloys was investigated via electrochemical measurement and immersion test. The Hank's solutions with neutral and acidic pH values were adopted as electrolytes to simulate the in vivo environment during normal and inflammatory response process. Furthermore, the local orbital density functional theory approach was employed to study the thermodynamical stability of Mg17Al12 phase. All the results proved the occurrence of pitting corrosion process with crackings for Mg17Al12 phase in Hank's solution, but with a much lower degradation rate compared with both AZ31 alloy and pure magnesium. Furthermore, a preliminary explanation on the biodegradation behaviors of Mg17Al12 phase was proposed. PMID:24411344

  6. Traps and defects in pre- and post-proton irradiated AlGaN-GaN high electron mobility transistors and AlGaN Schottky diodes

    NASA Astrophysics Data System (ADS)

    Sin, Yongkun; Foran, Brendan; Presser, Nathan; LaLumondiere, Stephen; Lotshaw, William; Moss, Steven C.

    2013-03-01

    High electron mobility transistors (HEMTs) based on AlGaN-GaN hetero-structures are promising for both commercial and military applications that require high voltage, high power, and high efficiency operation. Study of reliability and radiation effects of AlGaN-GaN HEMTs is necessary before solid state power amplifiers based on GaN HEMT technology are successfully deployed in satellite communication systems. Several AlGaN HEMT manufacturers have recently reported encouraging reliability data, but long-term reliability of these devices in the space environment still remains a major concern because a large number of traps and defects are present both in the bulk as well as at the surface leading to undesirable characteristics. This study is to investigate the effects of the AlGaN-GaN HEMTs and AlGaN Schottky diodes irradiated with protons.

  7. Tribocorrosion behavior of veneering biomedical PEEK to Ti6Al4V structures.

    PubMed

    Sampaio, Miguel; Buciumeanu, Mihaela; Henriques, Bruno; Silva, Filipe S; Souza, Júlio C M; Gomes, José R

    2016-02-01

    In dentistry, prosthetic structures must be able to support masticatory loads combined with a high biocompatibility and wear resistance in the presence of a corrosive environment. In order to improve the simultaneous wear and corrosion response of highly biocompatible prosthetic structures, a veneering poly-ether-ether-ketone (PEEK) to Ti6Al4V substrate was assessed by tribocorrosion analyses under conditions mimicking the oral environment. Samples were synthesized by hot pressing the PEEK veneer onto Ti6Al4V cylinders. The tribocorrosion tests on Ti6Al4V or PEEK/Ti6Al4V samples were performed on a reciprocating ball-on-plate tribometer at 30N normal load, 1Hz and stroke length of 3mm. The tests were carried out in artificial saliva at 37°C. Open circuit potential (OCP) was measured before, during and after reciprocating sliding tests. The worn surfaces were characterized by scanning electron microscopy. The results revealed a lower wear rate on PEEK combined with a lower coefficient of friction (COF), when compared to Ti6Al4V. In fact, PEEK protected Ti6Al4V substrate against the corrosive environment and wear avoiding the release of metallic ions to the surrounding environment. PMID:26454136

  8. AlSb/InAs/AlSb quantum wells

    NASA Technical Reports Server (NTRS)

    Kroemer, Herbert

    1990-01-01

    Researchers studied the InAs/AlSb system recently, obtaining 12nm wide quantum wells with room temperature mobilities up to 28,000 cm(exp 2)/V center dot S and low-temperature mobilities up to 325,000 cm(exp 2)/V center dot S, both at high electron sheet concentrations in the 10(exp 12)/cm(exp 2) range (corresponding to volume concentrations in the 10(exp 18)/cm(exp 2) range). These wells were not intentionally doped; the combination of high carrier concentrations and high mobilities suggest that the electrons are due to not-intentional modulation doping by an unknown donor in the AlSb barriers, presumably a stoichiometric defect, like an antisite donor. Inasmuch as not intentionally doped bulk AlSb is semi-insulating, the donor must be a deep one, being ionized only by draining into the even deeper InAs quantum well. The excellent transport properties are confirmed by other observations, like excellent quantum Hall effect data, and the successful use of the quantum wells as superconductive weak links between Nb electrodes, with unprecendentedly high critical current densities. The system is promising for future field effect transistors (FETs), but many processing problems must first be solved. Although the researchers have achieved FETs, the results so far have not been competitive with GaAs FETs.

  9. Mars Transportation Environment Definition Document

    NASA Technical Reports Server (NTRS)

    Alexander, M. (Editor)

    2001-01-01

    This document provides a compilation of environments knowledge about the planet Mars. Information is divided into three catagories: (1) interplanetary space environments (environments required by the technical community to travel to and from Mars); (2) atmospheric environments (environments needed to aerocapture, aerobrake, or use aeroassist for precision trajectories down to the surface); and (3) surface environments (environments needed to have robots or explorers survive and work on the surface).

  10. Multilayered TiAlN films on Ti6Al4V alloy for biomedical applications by closed field unbalanced magnetron sputter ion plating process.

    PubMed

    Yi, Peiyun; Peng, Linfa; Huang, Jiaqiang

    2016-02-01

    Ti6Al4V alloy has been widely used as a suitable material for surgical implants such as artificial hip joints. In this study, a series of multilayered gradient TiAlN coatings were deposited on Ti6Al4V substrate using closed field unbalanced magnetron sputter ion plating (CFUBMSIP) process. Taguchi design of experiment approach was used to reveal the influence of depositing parameters to the film composition and performance of TiAlN coatings. The phase structure and chemical composition of the TiAlN films were characterized by X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). Mechanical properties, including hardness, Young's modulus, friction coefficient, wear rate and adhesion strength were systematically evaluated. Potentiodynamic tests were conducted to evaluate the corrosion resistance of the coated samples in Ringer's solution at 37°C to simulate human body environment. Comprehensive performance of TiAlN films was evaluated by assigning different weight according to the application environment. S8, deposited by Ti target current of 8A, Al target current of 6A, bias voltage of -60V and nitrogen content with OEM (optical emission monitor) value of 45%, was found to achieve best performance in orthogonal experiments. Depositing parameters of S8 might be practically applied for commercialization of surgical implants. PMID:26652421

  11. Reduction in the Number of Mg Acceptors with Al Concentration in Al x Ga1- x N

    NASA Astrophysics Data System (ADS)

    Sunay, U. R.; Zvanut, M. E.; Allerman, A. A.

    2015-11-01

    High hole concentrations in Al x Ga1- x N become increasingly difficult to obtain as the Al mole fraction increases. The problem is believed to be related to compensation, extended defects, and the band gap of the alloy. Whereas electrical measurements are commonly used to measure hole density, in this work we used electron paramagnetic resonance (EPR) spectroscopy to investigate a defect related to the neutral Mg acceptor. The amount and symmetry of neutral Mg in MOCVD-grown Al x Ga1- x N with x = 0 to 0.28 was monitored for films with different dislocation densities and surface conditions. EPR measurements indicated that the amount of neutral Mg decreased by 60% in 900°C-annealed Al x Ga1- x N films for x = 0.18 and 0.28 as compared with x = 0.00 and 0.08. A decrease in the angular dependence of the EPR signal accompanied the increased x, suggesting a change in the local environment of the Mg. Neither dislocation density nor annealing conditions contribute to the reduced amount of neutral Mg in samples with the higher Al concentration. Rather, compensation is the simplest explanation of the observations, because a donor could both reduce the number of neutral acceptors and cause the variation in the angular dependence.

  12. Urban Environment Initiative

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The Urban Environment Initiative (UEI), has been established as part of a Cooperative Agreement with the National Aeronautics and Space Administration (NASA). The UEI is part of NASA's overall High Performance Computing and Communications (HPCC) and the Information Infrastructure Technology Applications (IITA) programs. The goal of the UEI is to provide public access to Earth Science information and promote its use with a focus on the environment of urban areas. This goal will be accomplished through collaborative efforts of the UEI team with both community-based and local/regional governmental organizations. The UEI team is comprised of four organizations representing private industry, NASA, and universities: Prime Technologies Service Corporation, NASA's Minority University Space Interdisciplinary Network (MU-SPIN) California State University, at Los Angeles, and Central State University (Wilberforce, OH). "Urban Environment" refers to the web of environmental, economic, and social factors that combine to create the urban world in which we live. Examples of these factors are population distribution, neighborhood demographic profiles, economic resources, business activities, location and concentration of environmental hazards and various pollutants, proximity and level of urban services, which form the basis of the urban environment and ultimately affect our lives and experiences. The use of Geographic Information Systems (GIS) and remote sensing allows data to be visualized in the forms of maps and spatial images. The use of these tools allow analysis of information about urban environments. Also included are descriptions of the four query types which will assist in understanding the maps.

  13. Quantum robots plus environments.

    SciTech Connect

    Benioff, P.

    1998-07-23

    A quantum robot is a mobile quantum system, including an on board quantum computer and needed ancillary systems, that interacts with an environment of quantum systems. Quantum robots carry out tasks whose goals include making specified changes in the state of the environment or carrying out measurements on the environment. The environments considered so far, oracles, data bases, and quantum registers, are seen to be special cases of environments considered here. It is also seen that a quantum robot should include a quantum computer and cannot be simply a multistate head. A model of quantum robots and their interactions is discussed in which each task, as a sequence of alternating computation and action phases,is described by a unitary single time step operator T {approx} T{sub a} + T{sub c} (discrete space and time are assumed). The overall system dynamics is described as a sum over paths of completed computation (T{sub c}) and action (T{sub a}) phases. A simple example of a task, measuring the distance between the quantum robot and a particle on a 1D lattice with quantum phase path dispersion present, is analyzed. A decision diagram for the task is presented and analyzed.

  14. Microgravity Environment Description Handbook

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard; McPherson, Kevin; Hrovat, Kenneth; Moskowitz, Milton; Rogers, Melissa J. B.; Reckart, Timothy

    1997-01-01

    The Microgravity Measurement and Analysis Project (MMAP) at the NASA Lewis Research Center (LeRC) manages the Space Acceleration Measurement System (SAMS) and the Orbital Acceleration Research Experiment (OARE) instruments to measure the microgravity environment on orbiting space laboratories. These laboratories include the Spacelab payloads on the shuttle, the SPACEHAB module on the shuttle, the middeck area of the shuttle, and Russia's Mir space station. Experiments are performed in these laboratories to investigate scientific principles in the near-absence of gravity. The microgravity environment desired for most experiments would have zero acceleration across all frequency bands or a true weightless condition. This is not possible due to the nature of spaceflight where there are numerous factors which introduce accelerations to the environment. This handbook presents an overview of the major microgravity environment disturbances of these laboratories. These disturbances are characterized by their source (where known), their magnitude, frequency and duration, and their effect on the microgravity environment. Each disturbance is characterized on a single page for ease in understanding the effect of a particular disturbance. The handbook also contains a brief description of each laboratory.

  15. Challenges for Life Support Systems in Space Environments, Including Food Production

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.

    2012-01-01

    Environmental Control and Life Support Systems (ECLSS) refer to the technologies needed to sustain human life in space environments. Histor ically these technologies have focused on providing a breathable atmo sphere, clean water, food, managing wastes, and the associated monitoring capabilities. Depending on the space agency or program, ELCSS has sometimes expanded to include other aspects of managing space enviro nments, such as thermal control, radiation protection, fire detection I suppression, and habitat design. Other times, testing and providing these latter technologies have been associated with the vehicle engi neering. The choice of ECLSS technologies is typically driven by the mission profile and their associated costs and reliabilities. These co sts are largely defined by the mass, volume, power, and crew time req uirements. For missions close to Earth, e.g., low-Earth orbit flights, stowage and resupply of food, some 0 2, and some water are often the most cost effective option. But as missions venture further into spa ce, e.g., transit missions to Mars or asteroids, or surface missions to Moon or Mars, the supply line economics change and the need to clos e the loop on life support consumables increases. These are often ref erred to as closed loop or regenerative life support systems. Regardless of the technologies, the systems must be capable of operating in a space environment, which could include micro to fractional g setting s, high radiation levels, and tightly closed atmospheres, including perhaps reduced cabin pressures. Food production using photosynthetic o rganisms such as plants by nature also provides atmospheric regenerat ion (e.g., CO2 removal and reduction, and 0 2 production), yet to date such "bioregenerative" technologies have not been used due largely t o the high power requirements for lighting. A likely first step in te sting bioregenerative capabilities will involve production of small a mounts of fresh foods to supplement to crew

  16. The effect of Si in Al-alloy on electromigration performance in Al filled vias

    NASA Astrophysics Data System (ADS)

    Kageyama, Makiko; Hashimoto, Keiichi; Onoda, Hiroshi

    1998-01-01

    Electromigration performance of vias filled with Al-Si-Cu alloys on Ti glue layers was investigated in comparison with W-stud vias. In Al-Si-Cu filled vias, voids were formed at only a few locations in the test structure, while voids were formed at every via in W-stud via chains. It is supposed that Al moves through the Al-Si-Cu via during electromigration in spite of the existence of a glue layer at the via bottom. This phenomenon was observed only in the vias filled with Al-Si-Cu alloy. Al movement was prohibited in Al-Cu filled vias. In Al-Si-Cu filled vias, an Al-Ti-Si alloy was formed at the via bottom while Al3Ti was formed at Al-Cu filled vias. Al is speculated to move through this Al-Ti-Si alloy during electromigration.

  17. Feasibility of creating a National ALS Registry using administrative data in the United States

    PubMed Central

    KAYE, WENDY E.; SANCHEZ, MARCHELLE; WU, JENNIFER

    2015-01-01

    Uncertainty about the incidence and prevalence of amyotrophic lateral sclerosis (ALS), as well as the role of the environment in the etiology of ALS, supports the need for a surveillance system/registry for this disease. Our aim was to evaluate the feasibility of using existing administrative data to identify cases of ALS. The Agency for Toxic Substances and Disease Registry (ATSDR) funded four pilot projects at tertiary care facilities for ALS, HMOs, and state based organizations. Data from Medicare, Medicaid, the Veterans Health Administration, and Veterans Benefits Administration were matched to data available from site-specific administrative and clinical databases for a five-year time-period (1 January 2001–31 December 2005). Review of information in the medical records by a neurologist was considered the gold standard for determining an ALS case. We developed an algorithm using variables from the administrative data that identified true cases of ALS (verified by a neurologist). Individuals could be categorized into ALS, possible ALS, and not ALS. The best algorithm had sensitivity of 87% and specificity of 85%. We concluded that administrative data can be used to develop a surveillance system/ registry for ALS. These methods can be explored for creating surveillance systems for other neurodegenerative diseases. PMID:24597459

  18. Microelectronics for harsh environments

    SciTech Connect

    McGarrity, J.M.; McLean, F.B. )

    1993-01-01

    Microelectronics is included on everybody's critical technology list for the future, and rightfully so. Each year, the role of microelectronics expands beyond its main market of consumer electronics and computers into areas such as home appliances, automobiles, aircraft, etc. The role of microelectronics in military equipment is similarly expanding. Some of these applications present highly stressing environments for the electronics, including high -temperatures and high radiation fields. Electronics that are robust - hardened to these environments - would offer great advantage in their capability to sense, control, and operate engines, machines, Power plants, and nuclear reactors with new levels of safety and reliability. Electronics under development to withstand these harsh environments include the following four semiconductor material technologies: silicon, GaAs, silicon carbide (SiC), and diamond.

  19. The hovercraft environment.

    PubMed

    Lovesey, E J

    1970-06-01

    In just over a decade the hovercraft has progressed from first prototype to a successful commercial form of transport which also has the ability to penetrate many environments hitherto virtually inaccessible to manned vehicles. Comparison with rival short range vehicles such as the helicopter and hydrofoil show that the hovercraft has become one of the most versatile forms of transport available. This versatility and ability to operate in unusual or extreme environments has been accompanied by the problems of control and of protection of the occupants of the hovercraft from the hazards associated with these environments. Several of these problems are discussed, together with their possible solutions. This article is based on a paper given to the Nederlands Vereniging Voor Ergonomie/Ergonomics Research Society joint conference at Noordwijk in Holland, 11-13 June, 1969. PMID:15676324

  20. The Space Radiation Environment

    NASA Technical Reports Server (NTRS)

    Bourdarie, Sebastien; Xapsos, Michael A.

    2008-01-01

    The effects of the space radiation environment on spacecraft systems and instruments are significant design considerations for space missions. Astronaut exposure is a serious concern for manned missions. In order to meet these challenges and have reliable, cost-effective designs, the radiation environment must be understood and accurately modeled. The nature of the environment varies greatly between low earth orbits, higher earth orbits and interplanetary space. There are both short-term and long-term variations with the phase of the solar cycle. In this paper we concentrate mainly on charged particle radiations. Descriptions of the radiation belts and particles of solar and cosmic origin are reviewed. An overview of the traditional models is presented accompanied by their application areas and limitations. This is followed by discussion of some recent model developments.

  1. ISS Microgravity Environment

    NASA Technical Reports Server (NTRS)

    Laible, Michael R.

    2011-01-01

    The Microgravity performance assessment of the International Space Station (ISS) is comprised of a quasi-steady, structural dynamic and a vibro-acoustic analysis of the ISS assembly-complete vehicle configuration. The Boeing Houston (BHOU) Loads and Dynamics Team is responsible to verify compliance with the ISS System Specification (SSP 41000) and USOS Segment (SSP 41162) microgravity requirements. To verify the ISS environment, a series of accelerometers are on-board to monitor the current environment. This paper summarizes the results of the analysis that was performed for the Verification Analysis Cycle (VAC)-Assembly Complete (AC) and compares it to on-orbit acceleration values currently being reported. The analysis will include the predicted maximum and average environment on-board ISS during multiple activity scenarios

  2. Automating the multiprocessing environment

    NASA Technical Reports Server (NTRS)

    Arpasi, Dale J.

    1989-01-01

    An approach to automate the programming and operation of tree-structured networks of multiprocessor systems is discussed. A conceptual, knowledge-based operating environment is presented, and requirements for two major technology elements are identified as follows: (1) An intelligent information translator is proposed for implementating information transfer between dissimilar hardware and software, thereby enabling independent and modular development of future systems and promoting a language-independence of codes and information; (2) A resident system activity manager, which recognizes the systems capabilities and monitors the status of all systems within the environment, is proposed for integrating dissimilar systems into effective parallel processing resources to optimally meet user needs. Finally, key computational capabilities which must be provided before the environment can be realized are identified.

  3. Quantum robots and environments

    SciTech Connect

    Benioff, P.

    1998-08-01

    Quantum robots and their interactions with environments of quantum systems are described, and their study justified. A quantum robot is a mobile quantum system that includes an on-board quantum computer and needed ancillary systems. Quantum robots carry out tasks whose goals include specified changes in the state of the environment, or carrying out measurements on the environment. Each task is a sequence of alternating computation and action phases. Computation phase activites include determination of the action to be carried out in the next phase, and recording of information on neighborhood environmental system states. Action phase activities include motion of the quantum robot and changes in the neighborhood environment system states. Models of quantum robots and their interactions with environments are described using discrete space and time. A unitary step operator T that gives the single time step dynamics is associated with each task. T=T{sub a}+T{sub c} is a sum of action phase and computation phase step operators. Conditions that T{sub a} and T{sub c} should satisfy are given along with a description of the evolution as a sum over paths of completed phase input and output states. A simple example of a task{emdash}carrying out a measurement on a very simple environment{emdash}is analyzed in detail. A decision tree for the task is presented and discussed in terms of the sums over phase paths. It is seen that no definite times or durations are associated with the phase steps in the tree, and that the tree describes the successive phase steps in each path in the sum over phase paths. {copyright} {ital 1998} {ital The American Physical Society}

  4. Emerging mechanisms of molecular pathology in ALS

    PubMed Central

    Peters, Owen M.; Ghasemi, Mehdi; Brown, Robert H.

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a devastating degenerative disease characterized by progressive loss of motor neurons in the motor cortex, brainstem, and spinal cord. Although defined as a motor disorder, ALS can arise concurrently with frontotemporal lobal dementia (FTLD). ALS begins focally but disseminates to cause paralysis and death. About 10% of ALS cases are caused by gene mutations, and more than 40 ALS-associated genes have been identified. While important questions about the biology of this disease remain unanswered, investigations of ALS genes have delineated pathogenic roles for (a) perturbations in protein stability and degradation, (b) altered homeostasis of critical RNA- and DNA-binding proteins, (c) impaired cytoskeleton function, and (d) non-neuronal cells as modifiers of the ALS phenotype. The rapidity of progress in ALS genetics and the subsequent acquisition of insights into the molecular biology of these genes provide grounds for optimism that meaningful therapies for ALS are attainable. PMID:25932674

  5. 3D Boltzmann Simulation of the Io's Plasma Environment: Comparison with Observational Data

    NASA Astrophysics Data System (ADS)

    Combi, M. R.; Lipatov, A. S.

    2003-12-01

    The global dynamics of the ionized and neutral components in the environment of Io plays an important role in the interaction of Jupiter's corotating magnetospheric plasma with Io [Combi et al., 2002; 1998; Kabin et al., 2001]. The stationary simulation of this problem was done in the MHD [Combi et al., 1998; Linker et al, 1998; Kabin et al., 2001] and the electrodynamic [Saur et al., 1999; 2003] approaches. In this report, we study the comparative role of ionization processes and charge exchange in formation of the plasma environment near Io by means of kinetic simulation. The atmosphere of Io is considered as an immobile obstacle in simulation. The comparison of results of such simulations with the Galileo spacecraft data is also discussed in this report. ~ M R Combi et al., J. Geophys. Res., 103, 9071, 1998. M R Combi, T I Gombosi, K Kabin, Atmospheres in the Solar System: Comparative\\ Aeronomy. Geophys. Monograph Series, 130, 151, 2002. K Kabin et al., Planetary and Space Sci., 49, 337, 2001. J A Linker et al., J. Geophys. Res., 103(E9), 19867, 1998. J Saur et al., J. Geophys. Res., 104, 25105, 1999. J Saur et al., ICARUS, 163, 456, 2003.

  6. Open system environment procurement

    NASA Technical Reports Server (NTRS)

    Fisher, Gary

    1994-01-01

    Relationships between the request for procurement (RFP) process and open system environment (OSE) standards are described. A guide was prepared to help Federal agency personnel overcome problems in writing an adequate statement of work and developing realistic evaluation criteria when transitioning to an OSE. The guide contains appropriate decision points and transition strategies for developing applications that are affordable, scalable and interoperable across a broad range of computing environments. While useful, the guide does not eliminate the requirement that agencies posses in-depth expertise in software development, communications, and database technology in order to evaluate open systems.

  7. NASA's Meteoroid Environment Office

    NASA Technical Reports Server (NTRS)

    Suggs, Robert M.; Cooke, William; McNamara, Heather

    2004-01-01

    The Meteoroid Environment Office (MEO) has recently been formed within the Engineering Directorate at NASA's Marshall Space Flight Center. With agency-wide responsibility for defining the meteoroid environments for spacecraft engineering operations purposes, the MEO will distribute a state-of-the-art sporadic meteoroid model as well as meteor shower forecasts for spacecraft operators. To improve these models and forecasts, the MEO will manage an observation and research program. Office responsibilities, products, and plans will be discussed in this paper. The MEO is sponsored by the Office of Safety and Mission Assurance at NASA Headquarters.

  8. Jupiter Environment Tool

    NASA Technical Reports Server (NTRS)

    Sturm, Erick J.; Monahue, Kenneth M.; Biehl, James P.; Kokorowski, Michael; Ngalande, Cedrick,; Boedeker, Jordan

    2012-01-01

    The Jupiter Environment Tool (JET) is a custom UI plug-in for STK that provides an interface to Jupiter environment models for visualization and analysis. Users can visualize the different magnetic field models of Jupiter through various rendering methods, which are fully integrated within STK s 3D Window. This allows users to take snapshots and make animations of their scenarios with magnetic field visualizations. Analytical data can be accessed in the form of custom vectors. Given these custom vectors, users have access to magnetic field data in custom reports, graphs, access constraints, coverage analysis, and anywhere else vectors are used within STK.

  9. Hazardous Environment Robotics

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Jet Propulsion Laboratory (JPL) developed video overlay calibration and demonstration techniques for ground-based telerobotics. Through a technology sharing agreement with JPL, Deneb Robotics added this as an option to its robotics software, TELEGRIP. The software is used for remotely operating robots in nuclear and hazardous environments in industries including automotive and medical. The option allows the operator to utilize video to calibrate 3-D computer models with the actual environment, and thus plan and optimize robot trajectories before the program is automatically generated.

  10. Environment scattering in GADRAS.

    SciTech Connect

    Thoreson, Gregory G.; Mitchell, Dean James; Theisen, Lisa Anne; Harding, Lee T.

    2013-09-01

    Radiation transport calculations were performed to compute the angular tallies for scattered gamma-rays as a function of distance, height, and environment. Green's Functions were then used to encapsulate the results a reusable transformation function. The calculations represent the transport of photons throughout scattering surfaces that surround sources and detectors, such as the ground and walls. Utilization of these calculations in GADRAS (Gamma Detector Response and Analysis Software) enables accurate computation of environmental scattering for a variety of environments and source configurations. This capability, which agrees well with numerous experimental benchmark measurements, is now deployed with GADRAS Version 18.2 as the basis for the computation of scattered radiation.

  11. Mood as Embodied Action: A Phenomenological Study of Interaction between Self and the Environment

    ERIC Educational Resources Information Center

    Manley, Dolores R.

    2009-01-01

    This phenomenological study explored the interaction between the affective phenomenon of mood (Davidson, et al., 2003) and embodied action (Varela, et al., 1993) experienced during interaction between self and the environment. Exploring the complementarity of mood and embodied action for organizations, teams, or individuals provided insightful…

  12. Local Structures around Si, Al and Na in Hydrated Silicate Glasses

    SciTech Connect

    Farges, Francois; Wispelaere, Sidoine de; Rossano, Stephanie; Munos, Manuel; Wilke, Max; Flank, Anne-Marie; Lagarde, Pierre

    2007-02-02

    XANES spectra were collected at the Si-, Al-, and Na K-edge in hydrous silicate glasses to understand the effect of water on the local structure around these cations. Around network forming Si and Al, no drastic changes are observed. Around Na, the dissolution of water creates more ordered environments in Al-bearing glasses and less ordered environment in Al-free glasses. Ab-initio XANES calculations were undertaken to understand the structural origins for these features. Based on these results, a bond valence model was refined that considers not only the present XANES experiments and models but also NMR information. The double percolation model refined explains, among others, the explosive properties of water-bearing hydrous melts, at the origin of a number of cataclysmic eruptions in subduction zones.

  13. Ab initio modeling of zincblende AlN layer in Al-AlN-TiN multilayers

    DOE PAGESBeta

    Yadav, S. K.; Wang, J.; Liu, X. -Y.

    2016-06-14

    An unusual growth mechanism of metastable zincblende AlN thin film by diffusion of nitrogen atoms into Al lattice is established. Using first-principles density functional theory, we studied the possibility of thermodynamic stability of AlN as a zincblende phase due to epitaxial strains and interface effect, which fails to explain the formation of zincblende AlN. We then compared the formation energetics of rocksalt and zincblende AlN in fcc Al through direct diffusion of nitrogen atoms to Al octahedral and tetrahedral interstitials. Furthermore, the formation of a zincblende AlN thin film is determined to be a kinetically driven process, not a thermodynamicallymore » driven process.« less

  14. The relationship between nighttime formation of gaseous HONO and nocturnal stability in an urban environment

    NASA Astrophysics Data System (ADS)

    McLaren, Robert; Wojtal, Patryk; Taylor, Peter

    2014-05-01

    nocturnal mixing suggest that the steady-state may result from an equilibrium between a surface reservoir source of HONO, reminiscent of those observed in the polluted marine boundary layer at night (Wojtal et al., Atmos. Chem. Phys., 11, 3243-3261, 2011).

  15. Synthesis of AlN/Al Polycrystals along with Al Nanoparticles Using Thermal Plasma Route

    SciTech Connect

    Kanhe, Nilesh S.; Nawale, A. B.; Kulkarni, N. V.; Bhoraskar, S. V.; Mathe, V. L.; Das, A. K.

    2011-07-15

    This paper for the first time reports the (200) oriented growth of hexagonal Aluminum nitride crystals during synthesis of aluminum nanoparticles in dc transferred arc thermal plasma reactor by gas phase condensation in nitrogen plasma. The structural and morphological study of as synthesized AlN crystal and aluminium nanoparticles was done by using the x-ray diffraction method, scanning electron microscopy and transmission electron microscopy.

  16. The Greenfoot Programming Environment

    ERIC Educational Resources Information Center

    Kolling, Michael

    2010-01-01

    Greenfoot is an educational integrated development environment aimed at learning and teaching programming. It is aimed at a target audience of students from about 14 years old upwards, and is also suitable for college- and university-level education. Greenfoot combines graphical, interactive output with programming in Java, a standard, text-based…

  17. "Everyman" and his Environment.

    ERIC Educational Resources Information Center

    Kinney, John E.

    Although we have accumulated much factual data on environmental conditions, interrelationships, and consequences of actions, our decisions are based on political expediency, pressure, mob action, and emotion. Believing that decisions regarding the environment and pollution control are not technical but socioeconomic, crusaders have refused…

  18. Birds, Examining Your Environment.

    ERIC Educational Resources Information Center

    MacBean, John C.; And Others

    Designed to provide new and different ways of observing birds rather than simply identifying them, this book attempts to develop skills for how to look at birds. Activities in each of the four sections, "Live Birds,""Birds' Eggs,""Birds' Nests," and "Dead Birds," are specifically planned to get one involved with birds in their natural environment.…

  19. Creating Adaptive Learning Environments

    ERIC Educational Resources Information Center

    Kopp, Stephen J.; Stanford, Linda Seestedt; Rohlfing, Kenneth; Kendall, Jonathan P.

    2004-01-01

    Educational expectations mandated by contemporary health care practice have expanded dramatically during the last decade. The Herbert H. and Grace A. Dow College of Health Professions at Central Michigan University has responded to this challenge through the creation of powerful pedagogical environments in its newly constructed health …

  20. Environment: Readings for Teachers.

    ERIC Educational Resources Information Center

    Ivany, J. W. George, Ed.

    Twenty-six articles or extracts from scholarly literature and one article written for this collection are contained in this anthology intended for teachers. The articles present the viewpoints of writers in a number of scientific and sociological fields concerning human interactions with their environment. Articles are arranged in the following…

  1. Economics and the Environment.

    ERIC Educational Resources Information Center

    Anderson, Curt L.

    This packet of lessons focuses on the complementary relationship between economic well-being and the natural resources of the environment. Students gain insight into a variety of environmental issues and learn to use economic analysis to understand these issues and seek solutions. The book contains 20 lessons divided into seven units. The units…

  2. Creating Respectful Classroom Environments

    ERIC Educational Resources Information Center

    Miller, Regina; Pedro, Joan

    2006-01-01

    Respect is a critical variable in education. It is critical to each individual child in the classroom environment as well as to the teaching and learning that takes place in the classroom. Children learn by example. Where do they get their examples? This article explores the parameters of teaching and encouraging respect in classrooms for young…

  3. Chandra Radiation Environment Modeling

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Blackwell, W. C.

    2003-01-01

    CRMFLX (Chandra Radiation Model of ion FluX) is a radiation environment risk mitigation tool for use as a decision aid in planning the operations times for Chandra's Advanced CCD Imaging Spectrometer (ACIS) detector. The accurate prediction of the proton flux environment with energies of 100 - 200 keV is needed in order to protect the ACIS detector against proton degradation. Unfortunately, protons of this energy are abundant in the region of space Chandra must operate, and on-board particle detectors do not measure proton flux levels of the required energy range. This presentation will describe the plasma environment data analysis and modeling basis of the CRMFLX engineering environment model developed to predict the proton flux in the solar wind, magnetosheath, and magnetosphere phenomenological regions of geospace. The recently released CRMFLX Version 2 implementation includes an algorithm that propagates flux from an observation location to other regions of the magnetosphere based on convective ExB and VB-curvature particle drift motions. This technique has the advantage of more completely filling out the database and makes maximum use of limited data obtained during high Kp periods or in areas of the magnetosphere with poor satellite flux measurement coverage.

  4. Multiprocessor programming environment

    SciTech Connect

    Smith, M.B.; Fornaro, R.

    1988-12-01

    Programming tools and techniques have been well developed for traditional uniprocessor computer systems. The focus of this research project is on the development of a programming environment for a high speed real time heterogeneous multiprocessor system, with special emphasis on languages and compilers. The new tools and techniques will allow a smooth transition for programmers with experience only on single processor systems.

  5. Communication Analysis of Environment.

    ERIC Educational Resources Information Center

    Malik, M. F.; Thwaites, H. M.

    This textbook was developed for use in a Concordia University (Quebec) course entitled "Communication Analysis of Environment." Designed as a practical application of information theory and cybernetics in the field of communication studies, the course is intended to be a self-instructional process, whereby each student chooses one information…

  6. Environment and the Humanities.

    ERIC Educational Resources Information Center

    Allen, Rodney F., Ed.; And Others

    As a conference report, the booklet is primarily devoted to abstracts of papers presented at a Conference on Environment and Humanities held in Tallahassee, Florida, April 25-27, 1976. Dr. Huston Smith of Syracuse University, the main speaker, addressed the issue of "Humanities and Environmental Awareness." Other topics discussed included: (1)…

  7. Understanding Our Environment: Water.

    ERIC Educational Resources Information Center

    Lieblich, Suzanne, Ed.

    Part of the Understanding Our Environment project that is designed to engage students in investigating specific environmental problems through concrete activities and direct experience, this unit uses an in-depth study of a local stream or river to raise questions about the nature, sources, and uses of water. Students begin by identifying the…

  8. Risk Analysis Virtual ENvironment

    2014-02-10

    RAVEN has 3 major functionalities: 1. Provides a Graphical User Interface for the pre- and post-processing of the RELAP-7 input and output. 2. Provides the capability to model nuclear power plants control logic for the RELAP-7 code and dynamic control of the accident scenario evolution. This capability is based on a software structure that realizes a direct connection between the RELAP-7 solver engine (MOOSE) and a python environment where the variables describing the plant statusmore » are accessible in a scripting environment. RAVEN support the generation of the probabilistic scenario control by supplying a wide range of probability and cumulative distribution functions and their inverse functions. 3. Provides a general environment to perform probability risk analysis for RELAP-7, RELAP-5 and any generic MOOSE based applications. The probabilistic analysis is performed by sampling the input space of the coupled code parameters and it is enhanced by using modern artificial intelligence algorithms that accelerate the identification of the areas of major risk (in the input parameter space). This environment also provides a graphical visualization capability to analyze the outcomes. Among other approaches, the classical Monte Carlo and Latin Hypercube sampling algorithms are available. For the acceleration of the convergence of the sampling methodologies, Support Vector Machines, Bayesian regression, and collocation stochastic polynomials chaos are implemented. The same methodologies here described could be used to solve optimization and uncertainties propagation problems using the RAVEN framework.« less

  9. Common HEP UNIX Environment

    NASA Astrophysics Data System (ADS)

    Taddei, Arnaud

    After it had been decided to design a common user environment for UNIX platforms among HEP laboratories, a joint project between DESY and CERN had been started. The project consists in 2 phases: 1. Provide a common user environment at shell level, 2. Provide a common user environment at graphical level (X11). Phase 1 is in production at DESY and at CERN as well as at PISA and RAL. It has been developed around the scripts originally designed at DESY Zeuthen improved and extended with a 2 months project at CERN with a contribution from DESY Hamburg. It consists of a set of files which are customizing the environment for the 6 main shells (sh, csh, ksh, bash, tcsh, zsh) on the main platforms (AIX, HP-UX, IRIX, SunOS, Solaris 2, OSF/1, ULTRIX, etc.) and it is divided at several "sociological" levels: HEP, site, machine, cluster, group of users and user with some levels which are optional. The second phase is under design and a first proposal has been published. A first version of the phase 2 exists already for AIX and Solaris, and it should be available for all other platforms, by the time of the conference. This is a major collective work between several HEP laboratories involved in the HEPiX-scripts and HEPiX-X11 working-groups.

  10. The Learning Environment.

    ERIC Educational Resources Information Center

    Shaver and Co., Salina, KS.

    The learning environment is discussed in terms of environmental components or factors that should be considered by the architect. The design factors to be considered and elaborated on are as follows--(1) program, (2) function, (3)light, (4) color, (5) acoustics, (6) temperature, (7) humidity, (8) spatial conformation, (9) structure, (10) site…

  11. Cleaning Up the Environment

    ERIC Educational Resources Information Center

    Pruett, Don; Pruett, Lindsay

    2005-01-01

    Environmental community service projects provide many opportunities for students to help the environment and connect with their communities. In Washington State, students are allowed to obtain a high school varsity letter in community service if they complete over 150 community service hours in a calendar year. To help students toward this goal,…

  12. Understanding Our Environment: People.

    ERIC Educational Resources Information Center

    Tweed, Ann

    Part of the Understanding Our Environment project that is designed to engage students in investigating specific environmental problems through concrete activities and direct experience, students work individually and in groups to plan a future community in order to gain an understanding of how greatly increased human populations impact resources,…

  13. Interactive Multimodal Learning Environments

    ERIC Educational Resources Information Center

    Moreno, Roxana; Mayer, Richard

    2007-01-01

    What are interactive multimodal learning environments and how should they be designed to promote students' learning? In this paper, we offer a cognitive-affective theory of learning with media from which instructional design principles are derived. Then, we review a set of experimental studies in which we found empirical support for five design…

  14. Understanding Our Environment: Life.

    ERIC Educational Resources Information Center

    Arndt, Laura M. Sanders

    This unit is part of the Understanding Our Environment project that is designed to engage students in investigating specific environmental problems through concrete activities and direct experience. Students begin by researching the migratory songbirds that live in their community. They determine the bird's roles in the ecosystems and their…

  15. Picturing the Natural Environment

    ERIC Educational Resources Information Center

    Johnson, Phyllis Scott

    2011-01-01

    Around Scout Island Education Center, a site used by schools in Fresno County to explore the area's natural environment, a total of 200 cylinder-shaped concrete stools display tiles representing small mammals, flying insects, birds, wildflowers, and more. Twenty sets have been created by elementary, middle, and high-school art students as part of…

  16. Environment, energy, and society

    SciTech Connect

    Humphrey, C.R.; Buttel, F.R.

    1986-01-01

    This book delineates the major ways in which human society and the environment affect each other. To study the structure of societies, it employs three conceptual models, or sociological paradigms, conservative, liberal, and radical. The book explains the courses in environmental sociology, international development, natural resources, agriculture, and urban or regional planning.

  17. SRB thermal environments

    NASA Technical Reports Server (NTRS)

    Crain, W. K.; Knox, E. C.; Frost, C. L.; Engel, C. D.

    1989-01-01

    The objective was to utilize and expand the Solid Rocket Booster (SRB) orbital flight test data base for better predictions of future flight environments. There were five tasks associated with this effort: analyze the internal aft skirt wind tunnel data and incorporate it into a data base for generating design and preflight reeentry thermal environments; generate reentry design thermal environments for the SRB steel case with the nozzle extension off; generate reentry design thermal environments for the SRB Filament Wound Case with the nozzle extension off; develop an engineering tool to analyze the 3-D flowfield around the SRB aft skirt during reentry for the purpose of obtaining the frequency and severity of the belching gas intrusion internal to the aft skirt; and perform SRM transient joint flow analysis for subscale and full scale motor firing as well as determine the effects of debonds of the insulation on the fill time and heating within the field joint insulation. In addition, this work was extended to provide support for the 51L Shuttle SRB failure analysis.

  18. The Learning Environment.

    ERIC Educational Resources Information Center

    American Electric Power System, New York, NY.

    The basic factors in personal comfort, the nature of the processes of teaching and learning, and the effects of environment on these functions are discussed. The role of climate conditioning and space conditioning as interpreted by sensory factors during the learning process gives guidelines for design solutions. Technical supplements on climate…

  19. The Prepared Environment.

    ERIC Educational Resources Information Center

    Ewert-Krocker, Laurie

    2001-01-01

    Uses Havighurst's 11 developmental tasks for normal adolescence as a basis for a discussion of the prepared environment for the adolescent; tasks include adjusting to a new physical self and intellectual abilities, establishing adult vocational goals, and establishing emotional and psychological independence from parents. Considers the needs and…

  20. Understanding Our Environment: Air.

    ERIC Educational Resources Information Center

    DiSpezio, Michael

    Part of the Understanding Our Environment project that is designed to engage students in investigating specific environmental problems through concrete activities and direct experience, this unit uses the contemporary dilemma of acid rain as a vehicle for teaching weather and the characteristics of air and atmosphere. The project involves a…

  1. Investigating Your Environment.

    ERIC Educational Resources Information Center

    Forest Service (USDA), Washington, DC.

    The goal of this interdisciplinary curriculum is to enable students to make informed and responsible decisions about natural resources management by promoting an understanding of natural, social, and economic environments and the student's role in affecting all three. The included investigations utilize processes and techniques that help people…

  2. Energy and the Environment

    ERIC Educational Resources Information Center

    Crawley, G. M.; Haynes, S. K.

    1975-01-01

    Provides the description and evaluation of a college-level undergraduate course dealing with energy and the environment. The intent of the course is to survey the social, political, economic, and moral considerations of the topic. The use of guest speakers is strongly advocated. (Author/CP)

  3. Oral environment and cancer.

    PubMed

    Kudo, Yasusei; Tada, Hidesuke; Fujiwara, Natsumi; Tada, Yoshiko; Tsunematsu, Takaaki; Miyake, Yoichiro; Ishimaru, Naozumi

    2016-01-01

    Cancer is now the leading cause of death in Japan. A rapid increase in cancer mortality is expected as Japan is facing a super-aged society. Many causes of cancer are known to be closely linked to life style factors, such as smoking, drinking, and diet. The oral environment is known to be involved in the pathogenesis and development of various diseases such as bronchitis, pneumonia, diabetes, heart disease, and dementia. Because the oral cavity acts as the bodily entrance for air and food, it is constantly exposed to foreign substances, including bacteria and viruses. A large number of bacteria are endemic to the oral cavity, and indigenous oral flora act to prevent the settlement of foreign bacteria. The oral environment is influenced by local factors, including dental plaque, tartar, teeth alignment, occlusion, an incompatible prosthesis, and bad lifestyle habits, and systemic factors, including smoking, consumption of alcohol, irregular lifestyle and eating habits, obesity, stress, hormones, and heredity. It has recently been revealed that the oral environment is associated with cancer. In particular, commensal bacteria in the oral cavity are involved in the development of cancer. Moreover, Candida, human papilloma virus and Epstein-Barr virus as well as commensal bacteria have been reported to be associated with the pathogenesis of cancer. In this review, we introduce recent findings of the correlation between the oral environment and cancer. PMID:27482300

  4. Libraries and the Environment.

    ERIC Educational Resources Information Center

    LaRue, James; And Others

    1991-01-01

    Three articles address issues that relate to libraries and the environment. Highlights include recycling projects; buying recycled paper products and other ecology-minded purchasing ideas; energy-efficient libraries; indoor pollution problems; a list of environmental information sources; designing library buildings; and activities that libraries…

  5. Monitoring the Environment

    ERIC Educational Resources Information Center

    Heins, Conrad F.; And Others

    1975-01-01

    New ways of obtaining environmental data are being developed to meet the demand for comprehensive, accurate, and timely information on the environment. This article examines four developments that are transforming the entire field of environmental measurement: spectroscopy; satellite transmission of environmental data; remote sensing; and…

  6. Understanding Our Environment: Land.

    ERIC Educational Resources Information Center

    Callister, Jeffrey C.; Crampton, Janet Wert

    Part of the Understanding Our Environment project that is designed to engage students in investigating specific environmental problems through concrete activities and direct experience, this unit introduces students to the idea of natural resources and focuses on resources found on land: minerals such as hematite and gypsum; rocks such as granite…

  7. Environment as Subjective Reality.

    ERIC Educational Resources Information Center

    Greenfield, Thomas B.

    The usual ways of thinking about organiztions represent them as physical or biological entities that respond to their environments as whole, integrated systems existing apart from individuals. Such images omit human will, imagination and moral choice. If we think about organizations in human terms, we must think about the capacity of individuals…

  8. NASA Integrated Services Environment

    NASA Technical Reports Server (NTRS)

    Ing, Sharon

    2005-01-01

    This slide presentation will begin with a discussion on NASA's current distributed environment for directories, identity management and account management. We will follow with information concerning the drivers, design, reviews and implementation of the NISE Project. The final component of the presentation discusses processes used, status and conclusions.

  9. Learning Environment: A Bibliography

    ERIC Educational Resources Information Center

    Kose, Sacit; Bag, Huseyin; Gezer, Kutret

    2007-01-01

    In this study, the Learning Environment Research-Bibliography includes studies on Educational subject. We have analyzed many journals, books, and theses published in international. The references listed here primarily focus on the empirical research related to the learning environmental research as an educational goal; along with a few learning…

  10. Virtual interface environment

    NASA Technical Reports Server (NTRS)

    Fisher, Scott S.

    1988-01-01

    A head-mounted, wide-angle, stereoscopic display system controlled by operator position, voice and gesture is under development for use as a multipurpose interface environment. Initial applications of the system are in telerobotics, data-management and human factors research. System configuration and research directions are described.

  11. Developing a Motivating Environment.

    ERIC Educational Resources Information Center

    Gordon, George Kenneth

    1982-01-01

    The author presents some generalizations about nursing home employees and recommendations for cultivating and maintaining a motivating environment for staff. Recommendations concern nursing home administration, employee recruitment and selection, stability of work groups, supervisory training, employee recognition, and public relations. (CT)

  12. Risk Analysis Virtual ENvironment

    SciTech Connect

    2014-02-10

    RAVEN has 3 major functionalities: 1. Provides a Graphical User Interface for the pre- and post-processing of the RELAP-7 input and output. 2. Provides the capability to model nuclear power plants control logic for the RELAP-7 code and dynamic control of the accident scenario evolution. This capability is based on a software structure that realizes a direct connection between the RELAP-7 solver engine (MOOSE) and a python environment where the variables describing the plant status are accessible in a scripting environment. RAVEN support the generation of the probabilistic scenario control by supplying a wide range of probability and cumulative distribution functions and their inverse functions. 3. Provides a general environment to perform probability risk analysis for RELAP-7, RELAP-5 and any generic MOOSE based applications. The probabilistic analysis is performed by sampling the input space of the coupled code parameters and it is enhanced by using modern artificial intelligence algorithms that accelerate the identification of the areas of major risk (in the input parameter space). This environment also provides a graphical visualization capability to analyze the outcomes. Among other approaches, the classical Monte Carlo and Latin Hypercube sampling algorithms are available. For the acceleration of the convergence of the sampling methodologies, Support Vector Machines, Bayesian regression, and collocation stochastic polynomials chaos are implemented. The same methodologies here described could be used to solve optimization and uncertainties propagation problems using the RAVEN framework.

  13. Toronto's Postwar Urban Environment.

    ERIC Educational Resources Information Center

    Hitchcock, John

    1984-01-01

    Discusses Toronto's postwar development as measured by: population growth patterns; households; families; age structure; dwelling type; and labor force participation. Growth rings based on municipal boundaries are used as the basis for all analyses. Policy issues related to physical/social environment and women's role related to urban growth are…

  14. Electrochemical Corrosion Characteristics of Arc-Ion-Plated AlTiN Coating for Marine Application.

    PubMed

    Lee, Jung-Hyung; Kim, MyoungJun; Kim, Seong-Jong

    2016-02-01

    In this study, aluminum titanium nitride (AlTiN) coating was deposited by arc ion plating onto mirror finish STS 304 plate. The surface and cross-section of the coating was characterized by SEM and EDX analysis. Several electrochemical corrosion experiments were performed including rest potential measurement, potentiodynamic polarization experiment and Tafel analysis. The result of the experiments indicated that the AlTiN coating presented lower corrosion current density than the substrate material (STS 304) under uniform corrosion environment. It was also observed that AlTiN coating may have a risk of being attacked by localized corrosion attack such as pitting when pores or micro/nano particles in the coating are exposed to chloride ion containing corrosion environment, especially marine environment. PMID:27433658

  15. Synthesis of Al-Al2O3 and Al-Aln Nanoparticle Composites Via Electric Explosion of Wires

    NASA Astrophysics Data System (ADS)

    Lerner, M. I.; Lozhkomoev, A. S.; Pervikov, A. V.; Bakina, O. V.

    2016-07-01

    Composite Al-Al2O3 and Al-AlN nanoparticles were synthesized via electric explosion of aluminum wires in an argon-oxygen gas mixture and in nitrogen. The parameters of electric explosion and gas medium affect the size and relative content of nitride and aluminum oxide in the nanoparticles. Processes of forming chemical compounds during aluminum oxidation at the contact surface between explosive products and gas and of nitrogen diffusions into the nanoparticles of the condensed phase are considered.

  16. Investigation of Wear Anisotropy in a Severely Deformed Al-Al3Ti Composite

    NASA Astrophysics Data System (ADS)

    El-Hadad, Shimaa; Sato, Hisashi; Watanabe, Yoshimi

    2012-09-01

    In the current investigation, Al-Al3Ti composite was processed by equal channel angular pressing (ECAP). ECAP was carried out using routes A and BC up to eight passes of deformation. It was observed that increasing the number of ECAP passes causes fragmentation of Al3Ti platelet particles and decreases their sizes compared to their original sizes in the undeformed Al-Al3Ti specimens. Moreover, the microstructure of route A-ECAPed Al-Al3Ti composite samples showed a strong alignment of the fragmented Al3Ti particles parallel to the pressing axis. On the other hand, ECAPed Al-Al3Ti alloy specimens by route BC have a relatively homogeneous distribution of Al3Ti particles. Because of the platelet Al3Ti particle fragmentation by ECAP, all the ECAPed specimens showed small anisotropy in their wear property in spite of this observed anisotropic microstructure induced by route A-ECAP.

  17. Investigation of Wear Anisotropy in a Severely Deformed Al-Al3Ti Composite

    NASA Astrophysics Data System (ADS)

    El-Hadad, Shimaa; Sato, Hisashi; Watanabe, Yoshimi

    2012-05-01

    In the current investigation, Al-Al3Ti composite was processed by equal channel angular pressing (ECAP). ECAP was carried out using routes A and BC up to eight passes of deformation. It was observed that increasing the number of ECAP passes causes fragmentation of Al3Ti platelet particles and decreases their sizes compared to their original sizes in the undeformed Al-Al3Ti specimens. Moreover, the microstructure of route A-ECAPed Al-Al3Ti composite samples showed a strong alignment of the fragmented Al3Ti particles parallel to the pressing axis. On the other hand, ECAPed Al-Al3Ti alloy specimens by route BC have a relatively homogeneous distribution of Al3Ti particles. Because of the platelet Al3Ti particle fragmentation by ECAP, all the ECAPed specimens showed small anisotropy in their wear property in spite of this observed anisotropic microstructure induced by route A-ECAP.

  18. NiAl-base composite containing high volume fraction of AlN for advanced engines

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan (Inventor); Whittenbeger, John D. (Inventor); Lowell, Carl F. (Inventor)

    1994-01-01

    A particulate reinforced NiAl-AlN composite alloy has a NiAl matrix and greater than about 13 volume percent fine particles of AlN within the matrix. The particles preferably have a diameter from about 15 nanometers to about 50 nanometers. The particulate reinforced NiAl-AlN composite alloy may be prepared by cryomilling prealloyed NiAl in liquid nitrogen using grinding media having a diameter of from about 2 to 6 mm at an impeller speed of from about 450 RPM to about 800 RPM. The cryomilling may be done for a duration of from about 4 hours to about 20 hours to obtain a cryomilled powder. The cryomilled powder may be consolidated to form the particulate reinforced NiAl-AlN composite alloy. The particulate reinforced alloy can further include a toughening alloy. The toughening alloy may include NiCrAlY, FeCrAlY, and FeAl.

  19. Environment Dependence of Interstellar Extinction Curves

    NASA Astrophysics Data System (ADS)

    Jenniskens, P.; Greenberg, J. M.

    1993-07-01

    The IUE interstellar extinction curves published by Aiello et al. (1988) are decomposed into a bump, linear rise and FUV non-linear rise, in the parameterization scheme of Fitzpatrick & Massa (1990). The parameters of the 115 extinction curves are given. The lines of sight are characterized from the IRAS Skyflux and Point Source Catalogue data. Mean extinction curves for each of the environments are given. The following environment specific behaviour has been found. We confirm that the linear rise is systematically less in dense media, corresponding to an accretion of their carriers on big grains in such environments. The bump is not weakened in dense media, but is sensitive to the presence of strong UV radiation fields. In HII regions we note abnormal behaviour of the bump width and a correlation of bump position and bump width. This argues against a removal of the bump carrier in HII regions by sticking to big grains. No environment specific behaviour for the FUV non-linear rise was noted except for a weak dependence on E(B-V)/d, notably in HII regions.

  20. Electronics for Extreme Environments

    NASA Astrophysics Data System (ADS)

    Patel, J. U.; Cressler, J.; Li, Y.; Niu, G.

    2001-01-01

    Most of the NASA missions involve extreme environments comprising radiation and low or high temperatures. Current practice of providing friendly ambient operating environment to electronics costs considerable power and mass (for shielding). Immediate missions such as the Europa orbiter and lander and Mars landers require the electronics to perform reliably in extreme conditions during the most critical part of the mission. Some other missions planned in the future also involve substantial surface activity in terms of measurements, sample collection, penetration through ice and crust and the analysis of samples. Thus it is extremely critical to develop electronics that could reliably operate under extreme space environments. Silicon On Insulator (SOI) technology is an extremely attractive candidate for NASA's future low power and high speed electronic systems because it offers increased transconductance, decreased sub-threshold slope, reduced short channel effects, elimination of kink effect, enhanced low field mobility, and immunity from radiation induced latch-up. A common belief that semiconductor devices function better at low temperatures is generally true for bulk devices but it does not hold true for deep sub-micron SOI CMOS devices with microscopic device features of 0.25 micrometers and smaller. Various temperature sensitive device parameters and device characteristics have recently been reported in the literature. Behavior of state of the art technology devices under such conditions needs to be evaluated in order to determine possible modifications in the device design for better performance and survivability under extreme environments. Here, we present a unique approach of developing electronics for extreme environments to benefit future NASA missions as described above. This will also benefit other long transit/life time missions such as the solar sail and planetary outposts in which electronics is out open in the unshielded space at the ambient space

  1. Clinical Perspective of Oxidative Stress in Sporadic ALS

    PubMed Central

    D’Amico, Emanuele; Factor-Litvak, Pam; Santella, Regina M.; Mitsumoto, Hiroshi

    2013-01-01

    Sporadic amyotrophic lateral sclerosis (sALS) is one of the most devastating neurological diseases; most patients die within 3 to 4 years after symptom onset. Oxidative stress is a disturbance in the pro-oxidative/anti-oxidative balance favoring the pro-oxidative state. Autopsy and laboratory studies in ALS indicate that oxidative stress plays a major role in motor neuron degeneration and astrocyte dysfunction. Oxidative stress biomarkers in cerebrospinal fluid, plasma, and urine, are elevated, suggesting that abnormal oxidative stress is generated outside of the central nervous system. Our review indicates that agricultural chemicals, heavy metals, military service, professional sports, excessive physical exertion, chronic head trauma, and certain foods might be modestly associated with ALS risk, with a stronger association between risk and smoking. At the cellular level, these factors are all involved in generating oxidative stress. Experimental studies indicate that a combination of insults that induce modest oxidative stress can exert additive deleterious effects on motor neurons, suggesting multiple exposures in real-world environments are important. As the disease progresses, nutritional deficiency, cachexia, psychological stress, and impending respiratory failure may further increase oxidative stress. Moreover, accumulating evidence suggests that ALS is possibly a systemic disease. Laboratory, pathologic, and epidemiologic evidence clearly support the hypothesis that oxidative stress is central in the pathogenic process, particularly in genetically susceptive individuals. If we are to improve ALS treatment, well-designed biochemical and genetic epidemiological studies, combined with a multidisciplinary research approach, are needed and will provide knowledge crucial to our understanding of ALS etiology, pathophysiology, and prognosis. PMID:23797033

  2. 77 FR 73732 - In the Matter of Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-11

    ... Matter of Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al-Jihad, aka The... al-Rafidayn, aka The Organization of al-Jihad's Base of Operations in Iraq, aka al-Qaida of Jihad in Iraq, aka al-Qaida in Iraq, aka al-Qaida in Mesopotamia, aka al-Qaida in the Land of the Two...

  3. Development of ODS-Fe{sub 3}Al alloys

    SciTech Connect

    Wright, I.G.; Pint, B.A.; Tortorelli, P.F.; McKamey, C.G.

    1997-12-01

    The overall goal of this program is to develop an oxide dispersion-strengthened (ODS) version of Fe{sub 3}Al that has sufficient creep strength and resistance to oxidation at temperatures in the range 1000 to 1200 C to be suitable for application as heat exchanger tubing in advanced power generation cycles. The main areas being addressed are: (a) alloy processing to achieve the desired alloy grain size and shape, and (b) optimization of the oxidation behavior to provide increased service life compared to semi-commercial ODS-FeCrAl alloys intended for the same applications. The recent studies have focused on mechanically-alloyed powder from a commercial alloy vendor. These starting alloy powders were very clean in terms of oxygen content compared to ORNL-produced powders, but contained similar levels of carbon picked up during the milling process. The specific environment used in milling the powder appears to exert a considerable influence on the post-consolidation recrystallization behavior of the alloy. A milling environment which produced powder particles having a high surface carbon content resulted in a consolidated alloy which readily recrystallized, whereas powder with a low surface carbon level after milling resulted in no recrystallization even at 1380 C. A feature of these alloys was the appearance of voids or porosity after the recrystallization anneal, as had been found with ORNL-produced alloys. Adjustment of the recrystallization parameters did not reveal any range of conditions where recrystallization could be accomplished without the formation of voids. Initial creep tests of specimens of the recrystallized alloys indicated a significant increase in creep strength compared to cast or wrought Fe{sub 3}Al, but the specimens failed prematurely by a mechanism that involved brittle fracture of one of the two grains in the test cross section, followed by ductile fracture of the remaining grain. The reasons for this behavior are not yet understood. The

  4. The Al-Al3Ni Eutectic Reaction: Crystallography and Mechanism of Formation

    NASA Astrophysics Data System (ADS)

    Fan, Yangyang; Makhlouf, Makhlouf M.

    2015-09-01

    The characteristics of the Al-Al3Ni eutectic structure are examined with emphasis on its morphology and crystallography. Based on these examinations, the mechanism of formation of this technologically important eutectic is postulated. It is found that a thin shell of α-Al forms coherently around each Al3Ni fiber. The excellent thermal stability of the Al-Al3Ni eutectic may be attributed to the presence of this coherent layer.

  5. Reply to Pachai et al.

    PubMed

    Harrison, William J; Bex, Peter J

    2016-05-01

    Peripheral vision is fundamentally limited by the spacing between objects. When asked to report a target's identity, observers make erroneous reports that sometimes match the identity of a nearby distractor and sometimes match a combination of target and distractor features. The classification of these errors has previously been used to support competing 'substitution' [1] or 'averaging' [2] models of the phenomenon known as 'visual crowding'. We recently proposed a single model in which both classes of error occur because observers make their reports by sampling from a biologically-plausible population of weighted responses within a region of space around the target [3]. It is critical to note that there is no probabilistic substitution or averaging process in our model; instead, we argue that neither substitution nor averaging occur, but that these are misclassifications of the distribution of reports that emerge when a population response distribution is sampled. This is a fundamentally different way of thinking about crowding, and on this basis we claim to have provided a mechanism unifying categorically distinct perceptual errors. Our goal was not to model all crowding phenomena, such as the release from crowding when target and flanks differ in color or depth [4]. Pachai et al.[5] have suggested that our model is not unifying because it inaccurately predicts perceptual performance for a particular stimulus. Although we agree that our model does not predict their data, this specific demonstration overlooks the critical aspect of the model: perceptual reports are drawn from a weighted population code. We show that Pachai et al.'s [5] own data actually provide evidence for the population code we have described [3], and we suggest a biologically-plausible analysis of their stimuli that provides a computational basis for their 'grouping' account of crowding. PMID:27166690

  6. Effects of the Al content on pore structures of porous TieAl alloys

    SciTech Connect

    Jaing, Y; He, Y H; Xu, N P; Zou, J; Huang, B; Lui, C T

    2008-01-01

    Porous TieAl alloys with different nominal compositions were fabricated through a reactive synthesis of Ti and Al elemental powders. It has been found that the pore parameters vary with the Al contents, indicating that the nature of the pores can be manipulated through changing the Al contents. In addition, detailed structural characterizations showed that the fabricated porous TieAl alloys can have three crystalline phases (i.e., a2-Ti3Al, g-TiAl, and TiAl3) when using different compositions. The fundamental reasons behind these phenomena have been explored.

  7. Benefits for Military Veterans with ALS

    MedlinePlus

    ... Chapters Certified Centers and Clinics Support Groups About ALS About Us Our Research In Your Community Advocate ... Veterans Resources for Military Veterans, Families & Survivors The ALS Association is working everyday to support people with ...

  8. Microalloying ultrafine grained Al alloys with enhanced ductility.

    PubMed

    Jiang, L; Li, J K; Cheng, P M; Liu, G; Wang, R H; Chen, B A; Zhang, J Y; Sun, J; Yang, M X; Yang, G

    2014-01-01

    Bulk ultrafine grained (UFG)/nanocrystal metals possess exceptional strength but normally poor ductility and thermal stability, which hinder their practical applications especially in high-temperature environments. Through microalloying strategy that enables the control of grains and precipitations in nanostructured regime, here we design and successfully produce a highly microstructure-stable UFG Al-Cu-Sc alloy with ~275% increment in ductility and simultaneously ~50% enhancement in yield strength compared with its Sc-free counterpart. Although the precipitations in UFG alloys are usually preferentially occurred at grain boundaries even at room temperature, minor Sc addition into the UFG Al-Cu alloys is found to effectively stabilize the as-processed microstructure, strongly suppress the θ-Al2Cu phase precipitation at grain boundary, and remarkably promote the θ'-Al2Cu nanoparticles dispersed in the grain interior in artificial aging. A similar microalloying strategy is expected to be equally effective for other UFG heat-treatable alloys. PMID:24398915

  9. Microalloying Ultrafine Grained Al Alloys with Enhanced Ductility

    PubMed Central

    Jiang, L.; Li, J. K.; Cheng, P. M.; Liu, G.; Wang, R. H.; Chen, B. A.; Zhang, J. Y.; Sun, J.; Yang, M. X.; Yang, G.

    2014-01-01

    Bulk ultrafine grained (UFG)/nanocrystal metals possess exceptional strength but normally poor ductility and thermal stability, which hinder their practical applications especially in high-temperature environments. Through microalloying strategy that enables the control of grains and precipitations in nanostructured regime, here we design and successfully produce a highly microstructure-stable UFG Al-Cu-Sc alloy with ~275% increment in ductility and simultaneously ~50% enhancement in yield strength compared with its Sc-free counterpart. Although the precipitations in UFG alloys are usually preferentially occurred at grain boundaries even at room temperature, minor Sc addition into the UFG Al-Cu alloys is found to effectively stabilize the as-processed microstructure, strongly suppress the θ-Al2Cu phase precipitation at grain boundary, and remarkably promote the θ′-Al2Cu nanoparticles dispersed in the grain interior in artificial aging. A similar microalloying strategy is expected to be equally effective for other UFG heat-treatable alloys. PMID:24398915

  10. Aluminium distribution in ZSM-5 revisited: The role of Al-Al interactions

    SciTech Connect

    Ruiz-Salvador, A. Rabdel; Grau-Crespo, Ricardo; Gray, Aileen E.; Lewis, Dewi W.

    2013-02-15

    We present a theoretical study of the distribution of Al atoms in zeolite ZSM-5 with Si/Al=47, where we focus on the role of Al-Al interactions rather than on the energetics of Al/Si substitutions at individual sites. Using interatomic potential methods, we evaluate the energies of the full set of symmetrically independent configurations of Al siting in a Si{sub 94}Al{sub 2}O{sub 192} cell. The equilibrium Al distribution is determined by the interplay of two factors: the energetics of the Al/Si substitution at an individual site, which tends to populate particular T sites (e.g., the T14 site), and the Al-Al interaction, which at this Si/Al maximises Al-Al distances in general agreement with Dempsey's rule. However, it is found that the interaction energy changes approximately as the inverse of the square of the distance between the two Al atoms, rather than the inverse of the distance expected if this were merely charge repulsion. Moreover, we find that the anisotropic nature of the framework density plays an important role in determining the magnitude of the interactions, which are not simply dependent on Al-Al distances. - Graphical abstract: Role of Al-Al interactions in high silica ZSM-5 is shown to be anisotropic in nature and not dependent solely on Coulombic interactions. Highlights: Black-Right-Pointing-Pointer Si-Al distribution in ZSM-5 is revisited, stressing the role of the Al-Al interaction. Black-Right-Pointing-Pointer Coulomb interactions are not the key factors controlling the Al siting. Black-Right-Pointing-Pointer Anisotropy of the framework is identified as a source of departure from Dempsey's rule.

  11. Photoelectrical, photophysical and photocatalytic properties of Al based MOFs: MIL-53(Al) and MIL-53-NH2(Al)

    NASA Astrophysics Data System (ADS)

    An, Yang; Li, Huiliang; Liu, Yuanyuan; Huang, Baibiao; Sun, Qilong; Dai, Ying; Qin, Xiaoyan; Zhang, Xiaoyang

    2016-01-01

    Two Al based MOFs (MIL-53(Al) and MIL-53-NH2 (Al)) were synthesized, and their photoelectrical, photophysical and photocatalytic properties towards oxygen evolution from water were investigated. Different from the ligand to metal charge transfer process previously reported, we proposes a new photocatalytic mechanism based on electron tunneling according to the results of theoretical calculation, steady state and time resolved fluorescence spectra. The organic linkers absorb photons, giving rise to electrons and holes. Then, the photogenerated electrons tunnel through the AlO6-octahedra, which not only inhibit the recombination of photogenerated charge carriers, but also is a key factor to the photocatalytic activity of Al based MOFs.

  12. Structural Investigation of AlN/SiOx Nanocomposite Hard Coatings Fabricated by Differential Pumping Cosputtering.

    PubMed

    Kawasaki, Masahiro; Nose, Masateru; Onishi, Ichiro; Shiojiri, Makoto

    2016-06-01

    AlN/SiO x nanocomposite coatings fabricated by differential pumping cosputtering (DPCS) were investigated by analytical electron microscopy. The DPCS system consists of two halves of a Chamber, A and B, for radio frequency (RF) magnetron sputtering deposition of different materials, and a substrate holder that rotates through the chambers. Al and SiO2 were sputtered in gas environments with a flow mixture of N2 and Ar gases at RF power of 200 W in the Al Chamber A and a flow of Ar gas at RF powers of 49 W in the SiO2 Chamber B. The substrates of (001) Si wafers heated at 250°C were rotated for 1,080 min at 3 rpm and alternately deposited by AlN and SiO2. AlN columnar crystals grew at a rate of ~0.3 nm/revolution preferentially along the hexagonal [0001] axis. Amorphous silicon oxide (a-SiO x ), deposited at a rate of ~0.2 nm/revolution, was coagulated preferentially along the boundaries between the AlN columns and also the interfaces between the subgrains within the AlN columns. The a-SiO x played an important role in the increase in mechanical hardness of the AlN/SiO x composite coating by disturbing deformation of AlN crystal lattices. PMID:27070831

  13. Investigation of the physicochemical aspects from natural kaolin to Al-MCM-41 mesoporous materials.

    PubMed

    Du, Chunfang; Yang, Huaming

    2012-03-01

    Aluminum-containing hexagonally ordered mesoporous silica Al-MCM-41 was synthesized by hydrothermal treatment of leached products produced by pre-grinding and subsequent acid leaching of natural kaolin, without addition of silica or aluminum regents. The resulting Al-MCM-41 had a high surface area of 1041 m(2)/g, a pore volume of 0.97 mL/g, and an average pore diameter of 3.7 nm with narrow pore size distribution centered at 2.7 nm. During the synthesis process of Al-MCM-41 from natural kaolin, the evolutions of chemical environments for Si and Al atoms should be emphasized. Wide angle X-ray diffraction (WAXRD), high-resolution transmission electron micrographs (HRTEMs), solid-state magic-angle-spinning nuclear magnetic resonance (MAS NMR), Fourier transform infrared spectroscopy (FT-IR) were used to trace the variations of chemical structures. Pretreatment of grinding and subsequent acid leaching acted as an important role in the whole synthesis process. NMR spectroscopy showed that Q(3) structure (Si(SiO)(3)(OH)), condensed Q(4) framework structure (Si(SiO)(4)), also the octahedral and tetrahedral Al existed in the leached sample and Al-MCM-41, with higher chemical contents of Q(4) structure and the octahedral Al in final product Al-MCM-41 than those in the leached sample. A possible mechanism for the formation of Al-MCM-41 from natural kaolin was suggested. PMID:22226501

  14. Thermal environment effects on strength and impact properties of boron-aluminum composites

    NASA Technical Reports Server (NTRS)

    Grimes, H. H.; Lad, R. A.; Maisel, J. E.

    1978-01-01

    A systematic study was conducted regarding the degradation of fracture strength and impact energy in commercial B-Al composites in both static and cyclic thermal environments. The composites used in the study contained approximately 50 vol % boron fibers, unidirectionally aligned in either a 6061 Al or 1100 Al matrix. The tensile strengths of the composites after 3000 thermal cycles as a function of upper cycle temperature are presented in graphs. The temperature at which the strengths of 6061 Al matrix, B-Al composites were significantly degraded after 3000 cycles was noticeably higher than that for the 1100 Al matrix composites. Static heating at 420 C resulted in no significant strength degradation for the 6061 Al matrix composites. In the case of 1100 matrix composites, some degradation was observed at 420 C but markedly less than in the composites cycled to 420 C.

  15. Solid-state 27Al and 29Si NMR characterization of hydrates formed in calcium aluminate silica fume mixtures

    NASA Astrophysics Data System (ADS)

    Pena, P.; Rivas Mercury, J. M.; de Aza, A. H.; Turrillas, X.; Sobrados, I.; Sanz, J.

    2008-08-01

    Partially deuterated Ca 3Al 2(SiO 4) y(OH) 12-4y-Al(OH) 3 mixtures, prepared by hydration of Ca 3Al 2O 6 (C 3A), Ca 12Al 14O 33 (C 12A 7) and CaAl 2O 4 (CA) phases in the presence of silica fume, have been characterized by 29Si and 27Al magic-angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopies. NMR spectroscopy was used to characterize anhydrous and fully hydrated samples. In hydrated compounds, Ca 3Al 2(OH) 12 and Al(OH) 3 phases were detected. From the quantitative analysis of 27Al NMR signals, the Al(OH) 3/Ca 3Al 2(OH) 12 ratio was deduced. The incorporation of Si into the katoite structure, Ca 3Al 2(SiO 4) 3-x(OH) 4x, was followed by 27Al and 29Si NMR spectroscopies. Si/OH ratios were determined from the quantitative analysis of 27Al MAS-NMR components associated with Al(OH) 6 and Al(OSi)(OH) 5 environments. The 29Si NMR spectroscopy was also used to quantify the unreacted silica and amorphous calcium aluminosilicate hydrates formed, C-S-H and C-A-S-H for short. From 29Si NMR spectra, the amount of Si incorporated into different phases was estimated. Si and Al concentrations, deduced by NMR, transmission electron microscopy, energy dispersive spectrometry, and Rietveld analysis of both X-ray and neutron data, indicate that only a part of available Si is incorporated in katoite structures.

  16. Can alumina particles be formed from Al hydroxide in the circumstellar media? A first-principles chemical study.

    PubMed

    Álvarez-Barcia, Sonia; Flores, Jesús R

    2016-02-17

    AlOH has been detected in the circumstellar envelope of an oxygen-rich supergiant star (VY CMa) and is an abundant Al-containing system. Water molecules have also been detected, even in a vibrationally excited state. The coalescence of AlOH units and other processes involving AlOH could be the source of alumina-type particles. The results indicate that the formation of (AlOH)2 dimers is barrier-free but (HAlO)2 systems are far more stable. The (AlOH)2 → (HAlO)2 transformation is hindered by substantial energy barriers but is probably moderately fast at very high temperatures. Water catalysis by relay (or Grotthuss-like) mechanisms substantially reduces those barriers to the point that, in the (AlOH)2·(H2O)2 system, the critical transition states lie clearly below 2AlOH + 2H2O. A surface or nucleation environment may favor the (AlOH)2 → (HAlO)2 conversion as to be kinetically competitive with water elimination ((AlOH)2·(H2O)n → (AlOH)2 + nH2O) in the hydrated systems. The hydrated (HAlO)2 structures can easily produce very stable hydrogenated Al2O3 and Al2O4 frames, which, to the same extent, can eliminate molecular hydrogen by exothermic processes. The remaining hydrogen atoms are exterior to the frames and perhaps could be removed by reaction with atomic hydrogen. The possible role of the coalescence of the undetected HAl(OH)2 and Al(OH)2 or AlO2H molecules is discussed. Al(OH)2 can easily be formed by reaction of AlO with a water molecule in exothermic barrier-free processes. PMID:26846699

  17. The Synergistic Engineering Environment

    NASA Technical Reports Server (NTRS)

    Cruz, Jonathan

    2006-01-01

    The Synergistic Engineering Environment (SEE) is a system of software dedicated to aiding the understanding of space mission operations. The SEE can integrate disparate sets of data with analytical capabilities, geometric models of spacecraft, and a visualization environment, all contributing to the creation of an interactive simulation of spacecraft. Initially designed to satisfy needs pertaining to the International Space Station, the SEE has been broadened in scope to include spacecraft ranging from those in low orbit around the Earth to those on deep-space missions. The SEE includes analytical capabilities in rigid-body dynamics, kinematics, orbital mechanics, and payload operations. These capabilities enable a user to perform real-time interactive engineering analyses focusing on diverse aspects of operations, including flight attitudes and maneuvers, docking of visiting spacecraft, robotic operations, impingement of spacecraft-engine exhaust plumes, obscuration of instrumentation fields of view, communications, and alternative assembly configurations. .

  18. Securing collaborative environments

    SciTech Connect

    Agarwal, Deborah; Jackson, Keith; Thompson, Mary

    2002-05-16

    The diverse set of organizations and software components involved in a typical collaboratory make providing a seamless security solution difficult. In addition, the users need support for a broad range of frequency and locations for access to the collaboratory. A collaboratory security solution needs to be robust enough to ensure that valid participants are not denied access because of its failure. There are many tools that can be applied to the task of securing collaborative environments and these include public key infrastructure, secure sockets layer, Kerberos, virtual and real private networks, grid security infrastructure, and username/password. A combination of these mechanisms can provide effective secure collaboration capabilities. In this paper, we discuss the requirements of typical collaboratories and some proposals for applying various security mechanisms to collaborative environments.

  19. The seamless computing environment

    SciTech Connect

    Sheehan, T.J.; Papadopoulos, P.M.; Alexander, R.

    1997-06-01

    Oak Ridge National Laboratory (ORNL), Sandia National Laboratories (SNL), and Pittsburgh Supercomputing Center (PSC) are in the midst of a project through which their supercomputers are linked via high speed networks. The goal of this project is to solve national security and scientific problems too large to run on a single machine. This project, as well as the desire to maximize the use of high performance computing systems, has provided the impetus to develop and implement software tools and infrastructure to automate the tasks associated with running codes on one or more heterogeneous machines from a geographically distributed pool. The ultimate goal of this effort is the Seamless Computing Environment (SCE). SCE is a production environment to which a user submits a job and receives results without having to worry about scheduling resources or even which resources the system uses. The compilation, data migration, scheduling, and execution will take place with minimal user intervention.

  20. Prions in the environment

    PubMed Central

    Saunders, Samuel E

    2008-01-01

    Scrapie and CWD are horizontally transmissible, and the environment likely serves as a stable reservoir of infectious prions, facilitating a sustained incidence of CWD in free-ranging cervid populations and complicating efforts to eliminate disease in captive herds. Prions will enter the environment through mortalities and/or shedding from live hosts. Unfortunately, a sensitive detection method to identify prion contamination in environmental samples has not yet been developed. An environmentally-relevant prion model must be used in experimental studies. Changes in PrPSc structure upon environmental exposure may be as significant as changes in PrPSc quantity, since the structure can directly affect infectivity and disease pathology. Prions strongly bind to soil and remain infectious. Conformational changes upon adsorption, competitive sorption and potential for desorption and transport all warrant further investigation. Mitigation of contaminated carcasses or soil might be accomplished with enzyme treatments or composting in lieu of incineration. PMID:19242120

  1. Nonstoichiometry of Al-Zr intermetallic phases

    SciTech Connect

    Radmilovic, V.; Thomas, G.

    1994-06-01

    Nonstoichiometry of metastable cubic {beta}{prime} and equilibrium tetragonal {beta} Al-Zr intermetallic phases of the nominal composition Al{sub 3}Zr in Al-rich alloys has been extensively studied. It is proposed that the ``dark contrast`` of {beta}{prime} core in {beta}{prime}/{sigma}{prime} complex precipitates, in Al-Li-Zr based alloys, is caused by incorporation of Al and Li atoms into the {beta}{prime} phase on Zr sublattice sites, forming nonstoichiometric Al-Zr intermetallic phases, rather than by Li partitioning only. {beta}{prime} particles contain very small amounts of Zr, approximately 5 at.%, much less than the stoichiometric 25 at.% in the Al{sub 3}Zr metastable phase. These particles are, according to simulation of high resolution images, of the Al{sub 3}(Al{sub 0.4}Li{sub 0.4}Zr{sub 0.2}) type. Nonstoichiometric particles of average composition Al{sub 4}Zr and Al{sub 6}Zr are observed also in the binary Al-Zr alloy, even after annealing for several hours at 600{degree}C.

  2. Simulation of atomic diffusion in the Fcc NiAl system: A kinetic Monte Carlo study

    SciTech Connect

    Alfonso, Dominic R.; Tafen, De Nyago

    2015-04-28

    The atomic diffusion in fcc NiAl binary alloys was studied by kinetic Monte Carlo simulation. The environment dependent hopping barriers were computed using a pair interaction model whose parameters were fitted to relevant data derived from electronic structure calculations. Long time diffusivities were calculated and the effect of composition change on the tracer diffusion coefficients was analyzed. These results indicate that this variation has noticeable impact on the atomic diffusivities. A reduction in the mobility of both Ni and Al is demonstrated with increasing Al content. As a result, examination of the pair interaction between atoms was carried out for the purpose of understanding the predicted trends.

  3. Pulling of 3 mm diameter AlSb rods by micro-pulling down method

    SciTech Connect

    Bourret-Courchesne Ph.D., Edith; Perrodin, Didier

    2009-05-14

    We designed and supplied special crucibles for AlSb material. Thermal insulation and limitation of Sb losses were our first work. The protection of the growth environment was also one of our priority to avoid any pollution of the Fibercryst {mu}PD facility. When this work was achieved, the next step was the calibration of the heating power for these new crucibles. Then, it was the definition of single crystal growth conditions that oriented our research. Following our proposal, many growths attempts were performed. We started from Al & Sb pure powder or from LBNL AlSb crystal as expected. We used different crucibles and different seeds.

  4. Environment control system

    DOEpatents

    Sammarone, Dino G.

    1978-01-01

    A system for controlling the environment of an enclosed area in nuclear reactor installations. The system permits the changing of the environment from nitrogen to air, or from air to nitrogen, without the release of any radioactivity or process gas to the outside atmosphere. In changing from a nitrogen to an air environment, oxygen is inserted into the enclosed area at the same rate which the nitrogen-oxygen gas mixture is removed from the enclosed area. The nitrogen-oxygen gas mixture removed from the enclosed area is mixed with hydrogen, the hydrogen recombining with the oxygen present in the gas to form water. The water is then removed from the system and, if it contains any radioactive products, can be utilized to form concrete, which can then be transferred to a licensed burial site. The process gas is purified further by stripping it of carbon dioxide and then distilling it to remove any xenon, krypton, and other fission or non-condensable gases. The pure nitrogen is stored as either a cryogenic liquid or a gas. In changing from an air to nitrogen environment, the gas is removed from the enclosed area, mixed with hydrogen to remove the oxygen present, dried, passed through adsorption beds to remove any fission gases, and reinserted into the enclosed area. Additionally, the nitrogen stored during the nitrogen to air change, is inserted into the enclosed area, the nitrogen from both sources being inserted into the enclosed area at the same rate as the removal of the gas from the containment area. As designed, the amount of nitrogen stored during the nitrogen to air change substantially equals that required to replace oxygen removed during an air to nitrogen change.

  5. Virtual System Environments

    SciTech Connect

    Vallee, Geoffroy R; Naughton, III, Thomas J; Ong, Hong Hoe; Tikotekar, Anand A; Engelmann, Christian; Bland, Wesley B; Aderholdt, Ferrol; Scott, Stephen L

    2008-01-01

    Distributed and parallel systems are typically managed with "static" settings: the operating system (OS) and the runtime environment (RTE) are specified at a given time and cannot be changed to fit an application's needs. This means that every time application developers want to use their application on a new execution platform, the application has to be ported to this new environment, which may be expensive in terms of application modifications and developer time. However, the science resides in the applications and not in the OS or the RTE. Therefore, it should be beneficial to adapt the OS and the RTE to the application instead of adapting the applications to the OS and the RTE. This document presents the concept of Virtual System Environments (VSE), which enables application developers to specify and create a virtual environment that properly fits their application's needs. For that four challenges have to be addressed: (i) definition of the VSE itself by the application developers, (ii) deployment of the VSE, (iii) system administration for the platform, and (iv) protection of the platform from the running VSE. We therefore present an integrated tool for the definition and deployment of VSEs on top of traditional and virtual (i.e., using system-level virtualization) execution platforms. This tool provides the capability to choose the degree of delegation for system administration tasks and the degree of protection from the application (e.g., using virtual machines). To summarize, the VSE concept enables the customization of the OS/RTE used for the execution of application by users without compromising local system administration rules and execution platform protection constraints.

  6. Electrophoresis. [in microgravity environment

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1977-01-01

    Ground-based techniques for electrophoresis take account of the need either to circumvent the effects of gravity to prevent convection, or to use gravity for fluid stabilization through artificial density gradients. The microgravity environments of orbiting spacecraft provides a new alternative for electrophoresis by avoiding the need for either of these two approaches. The paper presents some theoretical considerations concerning electrophoresis, examines certain experimental techniques (zone and high density gel electrophoresis, isoelectric focusing and isotachophoresis), and examines the electrophoresis of living cells.

  7. Extreme Environments: Why NASA?

    NASA Astrophysics Data System (ADS)

    Meyer, M. A.

    2002-12-01

    Life on our planet is the only known example in the universe and so we are relegated to this planet for the study of life. However, life may be a natural consequence of planet formation, and so the study of the origin, evolution, distribution and future of life may be greatly informed by planetary exploration. Astrobiology has adopted several approaches to study life on Earth, for deducing our origins, for determining the likelihood of life elsewhere, and for enabling the search for evidence of past or present life. The first approach has been the Exobiology Program, centered around understanding the origins of life and which supports individual investigator research. Second has been the construction of consortia-type research in which researchers from different disciplines focus on a larger problem. This structure began with NASA Specialized Centers of Research and Training and has grown to include the Astrobiology Institute - a collection of competitively selected groups of researchers attacking problems in Astrobiology as individual teams and as a consolidated Institute. With the formation of an intellectual basis for exploring for life elsewhere, Astrobiology has initiated the competitive research and development program in instrument development (Astrobiology Science and Technology for Instrument Development [ASTID] Program) that would enable future mission instruments for the exploration of planetary bodies in the search for prebiotic chemistry, habitable environments (past or present), biomarkers, and possibly life itself. However, the act of exploring requires robust instrumentation, mobile robotic platforms, efficient operations, and a high level of autonomy. To this end, Astrobiology has started a new research activity that promotes scientifically-driven robotic exploration of extreme environments on Earth that are analogous to suspected habitable environments on other planetary bodies. The program is called Astrobiology Science and Technology for

  8. The physical environment influences neuropsychiatric symptoms and other outcomes in assisted living residents

    PubMed Central

    Bicket, Mark C.; Samus, Quincy M.; McNabney, Mathew; Onyike, Chiadi U.; Mayer, Lawrence S.; Brandt, Jason; Rabins, Peter; Lyketsos, Constantine; Rosenblatt, Adam

    2011-01-01

    Objective Although the number of elderly residents living in assisted living (AL) facilities is rising, few studies have examined the AL physical environment and its impact on resident well-being. We sought to quantify the relationship of AL physical environment with resident outcomes including neuropsychiatric symptoms (NPS), quality of life (QOL), and fall risk, and to compare the effects for demented and non-demented residents. Methods Prospective cohort study of a stratified random sample of 326 AL residents living in 21 AL facilities. Measures included the Therapeutic Environmental Screening Scale for Nursing Homes and Residential Care (TESS-NH/RC) to rate facilities and in-person assessment of residents for diagnosis (and assessment of treatment) of dementia, ratings on standardized clinical, cognitive, and QOL measures. Regression models compared environmental measures with outcomes. TESS-NH/RC is modified into a scale for rating the AL physical environment AL-EQS. Results The AL Environmental Quality Score (AL-EQS) was strongly negatively associated with Neuropsychiatric Inventory (NPI) total score (p <0.001), positively associated with Alzheimer Disease Related Quality of Life (ADRQL) score (p = 0.010), and negatively correlated with fall risk (p = 0.042). Factor analysis revealed an excellent two-factor solution, Dignity and Sensory. Both were strongly associated with NPI and associated with ADRQL. Conclusion The physical environment of AL facilities likely affects NPS and QOL in AL residents, and the effect may be stronger for residents without dementia than for residents with dementia. Environmental manipulations that increase resident privacy, as well as implementing call buttons and telephones, may improve resident well-being. PMID:20077498

  9. Cyclic oxidation resistance of a reaction milled NiAl-AlN composite

    NASA Technical Reports Server (NTRS)

    Lowell, Carl E.; Barrett, Charles A.; Whittenberger, J. D.

    1990-01-01

    Based upon recent mechanical property tests a NiAl-AlN composite produced by cryomilling has very attractive high temperature strength. This paper focuses on the oxidation resistance of the NiAl-AlN composite at 1473 and 1573 K as compared to that of Ni-47Al-0.15Zr, one of the most oxidation resistant intermetallics. The results of cyclic oxidation tests show that the NiAl-AlN composite has excellent properties although not quite as good as those of Ni-47Al-0.15Zr. The onset of failure of the NiAl-AlN was unique in that it was not accompanied by a change in scale composition from alumina to less protective oxides. Failure in the composite appears to be related to the entrapment of AlN particles within the alumina scale.

  10. 3D Boltzmann Simulation of the Io's Plasma Environment with Adaptive Mesh and Particle Refinement

    NASA Astrophysics Data System (ADS)

    Lipatov, A. S.; Combi, M. R.

    2002-12-01

    The global dynamics of the ionized and neutral components in the environment of Io plays an important role in the interaction of Jupiter's corotating magnetospheric plasma with Io [Combi et al., 2002; 1998; Kabin et al., 2001]. The stationary simulation of this problem was done in the MHD [Combi et al., 1998; Linker et al, 1998; Kabin et al., 2001] and the electrodynamic [Saur et al., 1999] approaches. In this report, we develop a method of kinetic ion-neutral simulation, which is based on a multiscale adaptive mesh, particle and algorithm refinement. This method employs the fluid description for electrons whereas for ions the drift-kinetic and particle approaches are used. This method takes into account charge-exchange and photoionization processes. The first results of such simulation of the dynamics of ions in the Io's environment are discussed in this report. ~ M R Combi et al., J. Geophys. Res., 103, 9071, 1998. M R Combi, T I Gombosi, K Kabin, Atmospheres in the Solar System: Comparative\\ Aeronomy. Geophys. Monograph Series, 130, 151, 2002. K Kabin et al., Planetary and Space Sci., 49, 337, 2001. J A Linker et al., J. Geophys. Res., 103(E9), 19867, 1998. J Saur et al., J. Geophys. Res., 104, 25105, 1999.

  11. CCTV for radiation environments

    SciTech Connect

    Shaufl, R.A.

    1985-01-01

    The use of closed circuit television (CCTV) within radiation environments requires the system designer to have a thorough knowledge of the application environment and the electronic and optical components expected to survive within the environment. Of all the many ambient conditions to which CCTV components are exposed, from an air-conditioned office complex to 1,000 feet under the ocean, none is as demanding as the radiation encountered in the nuclear industrial field. Unhardened CCTV equipment can fail or degrade to the point of being useless when exposed to ionizing radiation doses of as little as 10/sup 3/ rads (Si) or to a neutron fluence of as little as 10/sup 11/ neutrons per square centimeter. (Rads (Si) stands for roentgens absorbed dose in silicon, while a fluence is defined as the time integral of neutron flux.) The applications for CCTV systems may require that each component within the system withstand a total ionizing radiation dose of 10/sup 8/ rads or greater.

  12. Volcanoes and the Environment

    NASA Astrophysics Data System (ADS)

    Marti, Edited By Joan; Ernst, Gerald G. J.

    2005-10-01

    Volcanoes and the Environment is a comprehensive and accessible text incorporating contributions from some of the world's authorities in volcanology. This book is an indispensable guide for those interested in how volcanism affects our planet's environment. It spans a wide variety of topics from geology to climatology and ecology; it also considers the economic and social impacts of volcanic activity on humans. Topics covered include how volcanoes shape the environment, their effect on the geological cycle, atmosphere and climate, impacts on health of living on active volcanoes, volcanism and early life, effects of eruptions on plant and animal life, large eruptions and mass extinctions, and the impact of volcanic disasters on the economy. This book is intended for students and researchers interested in environmental change from the fields of earth and environmental science, geography, ecology and social science. It will also interest policy makers and professionals working on natural hazards. An all-inclusive text that goes beyond the geological working of volcanoes to consider their environmental and sociological impacts Each chapter is written by one of the world's leading authorities on the subject Accessible to students and researchers from a wide variety of backgrounds

  13. Obesity and Economic Environments

    PubMed Central

    Sturm, Roland; An, Ruopeng

    2014-01-01

    This review summarizes our understanding of economic factors during the obesity epidemic and dispels some widely held, but incorrect, beliefs: Rising obesity rates coincided with increases in leisure time (rather than increased work hours), increased fruit and vegetable availability (rather than a decline of healthier foods), and increased exercise uptake. As a share of disposable income, Americans now have the cheapest food available in history, which fueled the obesity epidemic. Weight gain was surprisingly similar across sociodemographic groups or geographic areas, rather than specific to some groups (at every point in time, however, there are clear disparities). It suggests that if we want to understand the role of the environment in the obesity epidemic, we need to understand changes over time affecting all groups, not differences between subgroups at a given time. Although economic and technological changes in the environment drove the obesity epidemic, the evidence for effective economic policies to prevent obesity remains limited. Taxes on foods with low nutritional value could nudge behavior towards healthier diets, as could subsidies/discounts for healthier foods. However, even a large price change for healthy foods could only close a part of the gap between dietary guidelines and actual food consumption. Political support has been lacking for even moderate price interventions in the US and this may continue until the role of environment factors is accepted more widely. As opinion leaders, clinicians play an important role to shape the understanding of the causes of obesity. PMID:24853237

  14. Fitness in fluctuating environments

    NASA Astrophysics Data System (ADS)

    Tanase Nicola, Sorin; Nemenman, Ilya

    2011-03-01

    Often environments change faster than the time needed to evolve optimal phenotypes through cycles of mutation and selection. We focus on this case, but assume that environmental oscillations are slower than an individual's lifetime. This is relevant, for example, for bacterial populations confronted with daily environmental changes. We analyze a resource-limited competition between a mutant phenotype and the ancestor. Environmental dynamics is represented by periodically varying, off-phase parameters of the corresponding Lotka-Volterra model. For the very slow dynamics (but still faster than the fixation time scale) the strength and the sign of selection are functions of the birth/death rates averaged over all of the environmental states and independent of the period of the fluctuations. For faster fluctuations, selection depends on the particular sequence of the successive environmental states. In particular, a time reversal of the environmental dynamics can change the sign of the selection. We conclude that the fittest phenotype in a changing environment can be very different from both the optimal phenotype in the average environment, and the phenotype with the largest average fitness.

  15. First-principles investigations of Ni3Al(111) and NiAl(110) surfaces at metal dusting conditions

    SciTech Connect

    Saadi, Souheil

    2011-03-01

    We investigate the structure and surface composition of the {gamma}{prime}-Ni{sub 3}Al(111) and {beta}-NiAl(110) alloy surfaces at conditions relevant for metal dusting corrosion related to catalytic steam reforming of natural gas. In regular service as protective coatings, nickel-aluminum alloys are protected by an oxide scale, but in case of oxide scale spallation, the alloy surface may be directly exposed to the reactive gas environment and vulnerable to metal dusting. By means of density functional theory and thermochemical calculations for both the Ni{sub 3}Al and NiAl surfaces, the conditions under which CO and OH adsorption is to be expected and under which it is inhibited, are mapped out. Because CO and OH are regarded as precursors for nucleating graphite or oxide on the surfaces, phase diagrams for the surfaces provide a simple description of their stability. Specifically, this study shows how the CO and OH coverages depend on the steam to carbon ratio (S/C) in the gas and thereby provide a ranking of the carbon limits on the different surface phases.

  16. Measurement of 25Al+p resonant elastic scattering for studying the 25Al(p,γ)26Si

    NASA Astrophysics Data System (ADS)

    Kwon, Y. K.; Lee, C. S.; Jung, H. S.; Moon, J. Y.; Lee, J. H.; Yun, C. C.; Kubono, S.; Yamaguchi, H.; Hashimoto, T.; Kahl, D.; Hayakawa, S.; Choi, Seonho; Kim, M. J.; Kim, Y. H.; Kim, Y. K.; Park, J. S.; Kim, E. J.; Moon, C.-B.; Teranishi, T.; Wakabayashi, Y.; Iwasa, N.; Yamada, T.; Togano, Y.; Kato, S.; Cherubini, S.; Rapisarda, G. G.

    2012-11-01

    Proton resonant states in 26Si have been studied by the resonant elastic scattering of 25Al+p with a 25Al radioactive ion beam at 2.863 MeV/nucleon bombarding a thick H2 gas target with the inverse kinematics method at the low-energy RI beam facility CRIB (CNS Radioactive Ion Beam separator), University of Tokyo. The properties of these resonance states are important to better determine the production rates of 25Al(p,γ)26Si reaction, which is one of the astrophysically important nuclear reactions to understand the production of the ground state of 26Al, the emitter of its characteristic 1.809-MeV gamma-ray, under the explosive stellar environments such as novae and X-ray bursts. In this work, several resonances above the proton threshold level have been observed with a high statistics and background free through a covered the range of excitation energies from Ex ~ 6.8 to 8.2 MeV.

  17. Cenomanian-Turonian biostratigraphy of the Jardas Al Abid area, Al Jabal Al Akhdar, northeast Libya

    NASA Astrophysics Data System (ADS)

    El Qot, Gamal M.; Abdulsamad, Esam O.

    2016-09-01

    The Upper Cenomanian-Turonian succession exposed at Jardas al'Abid area consists mainly of carbonates with siliciclastic intercalations. This succession is subdivided lithostratigraphically into: Qasr al'Abid (Late Cenomanian) and Al Baniyah (Late Cenomanian-Coniacian) formations. This sequence is relatively rich in macrofossil assemblages especially bivalves, gastropods, and echinoids with rare ammonites. Based on the first occurrence (FO) and last occurrence (LO) of some index species of these macrofossil groups, an integrated biostratigraphic framework has been constructed. The studied Cenomanian-Turonian sequence is subdivided biostratigraphically into three ammonite biozones; Pseudaspidoceras pseudonodosoides Total Range Zone, Choffaticeras segne Total Range Zone, and Coilopoceras requienianum Total Range Zone. Based on the rest of macrofossil assemblages other than the ammonites, eight biozones were recognized; Mecaster batnensis Total Range Zone, Ceratostreon flabellatum-Neithea dutrugei Acme Zone, Costagyra olisiponensis Acme Zone, Pycnodonte (Phygraea) vesicularis vesiculosa Acme Zone, Mytiloides labiatus Total Range Zone = Mecaster turonensis Acme Zone, Rachiosoma rectilineatum-Curvostrea rouvillei-Tylostoma (T.) globosum Assemblage Zone, Radiolites sp.-Apricardia? matheroni Total Range Zone, and Nerinea requieniana Total Range Zone. Most of the proposed biozones are recorded for the first time from Libya. The integration among these biozones as well as local and inter-regional correlation of the biozones have been discussed. The stage boundaries of the studied stratigraphic intervals are discussed, where the Cenomanian/Turonian boundary is delineated at the last occurrence (LO) of Pseudaspidoceras pseudonodosoides (Choffat), while the Turonian/Coniacian boundary is delineated arbitrary being agree with the LO of the Turonian fauna.

  18. Effects of Interstitial Boron and Alloy Stoichiometry on Environmental Effects in FeAl

    SciTech Connect

    Cohron, J.W.; George, E.P.; Zee, R.H.

    1998-04-22

    Room-temperature tensile tests were conducted on B-doped (300 wppm) and B-free polycrystalline FeAl alloys containing 37, 40, 45, and 48 at. % aluminum in pure hydrogen gas at pressures in the range of 10 sup minus 8 to 10 sup 3 Pa. The ductilities of both B-free and B-doped FeAl decreased with increasing Al content. However, at a given Al level, the ductility of B-doped FeAl was higher than that of its B-free counterpart. Fracture mode was independent of environment and dependent mainly on stoichiometry. Ductility was found to be very sensitive to environment, particularly in the lower Al alloys. Alloys that exhibited >10% ductility in UHV showed a decrease in elongation to fracture with increasing hydrogen pressure. Tests conducted in dry hydrogen gas result in greater ductilities than those conducted in air, indicating that water vapor is more detrimental than H sub 2 to the ductility of FeAl alloys.

  19. Characterization of Atmospheric Corrosion of 2A12 Aluminum Alloy in Tropical Marine Environment

    NASA Astrophysics Data System (ADS)

    Li, T.; Li, X. G.; Dong, C. F.; Cheng, Y. F.

    2010-06-01

    In this work, corrosion product formed on 2A12 aluminum (Al) alloy after 3 months of natural exposure in South China Sea atmosphere was characterized by various surface analysis techniques, including scanning electron microscopy, energy-dispersive x-ray analysis, x-ray photoelectron spectroscopy, and x-ray diffraction. The atmospheric corrosion mechanism of Al alloy in marine environment was derived. Results demonstrated that Al alloy specimen experiences serious general corrosion and pitting corrosion. Al and O are enriched in the product film, and Ca and Cl are also found in the film and corrosion pits in Al alloy substrate. The main component compounds existing in the film include Al2O3, Al(OH)3, and AlOOH while AlCl3 and CaCO3 are also identified. Al alloy encounters corrosion under tropical marine atmosphere. Although somewhat protective, the formed surface film on Al alloy specimen is attacked by chloride ions, resulting in significant pitting corrosion of Al alloy.

  20. Systems Engineering Techniques for ALS Decision Making

    NASA Technical Reports Server (NTRS)

    Rodriquez, Luis F.; Drysdale, Alan E.; Jones, Harry; Levri, Julie A.

    2004-01-01

    The Advanced Life Support (ALS) Metric is the predominant tool for predicting the cost of ALS systems. Metric goals for the ALS Program are daunting, requiring a threefold increase in the ALS Metric by 2010. Confounding the problem, the rate new ALS technologies reach the maturity required for consideration in the ALS Metric and the rate at which new configurations are developed is slow, limiting the search space and potentially giving the perspective of a ALS technology, the ALS Metric may remain elusive. This paper is a sequel to a paper published in the proceedings of the 2003 ICES conference entitled, "Managing to the metric: an approach to optimizing life support costs." The conclusions of that paper state that the largest contributors to the ALS Metric should be targeted by ALS researchers and management for maximum metric reductions. Certainly, these areas potentially offer large potential benefits to future ALS missions; however, the ALS Metric is not the only decision-making tool available to the community. To facilitate decision-making within the ALS community a combination of metrics should be utilized, such as the Equivalent System Mass (ESM)-based ALS metric, but also those available through techniques such as life cycle costing and faithful consideration of the sensitivity of the assumed models and data. Often a lack of data is cited as the reason why these techniques are not considered for utilization. An existing database development effort within the ALS community, known as OPIS, may provide the opportunity to collect the necessary information to enable the proposed systems analyses. A review of these additional analysis techniques is provided, focusing on the data necessary to enable these. The discussion is concluded by proposing how the data may be utilized by analysts in the future.

  1. Evolution of microstructure and mechanical properties in laser induced reaction coating of Al{sub 2}O{sub 3} on SiC/Al{sub 2}O{sub 3} composite

    SciTech Connect

    Dahotre, N.B.; Xiao, C.; Boss, W.; McCay, M.H.; McCay, T.D.

    1996-12-31

    Protection of a SiC(p)/Al2O3 composite (SiC particulate-reinforced Al{sub 2}O{sub 3}-matrix) at high temperature from deleterious reactions occurring within and with the surrounding environment is required for high temperature applications. Development of a continuous Al2O3 coating on SiC(p)/Al2O3 ceramic composite for such protection is achieved using the laser assisted in-situ reaction technique. The as-deposited alumina coating was analyzed using optical microscopy and XRD. The coated samples were also evaluated for mechanical properties using 3-point bend tests.

  2. The Complete Genome Sequence of Bacillus thuringiensis Al Hakam▿

    PubMed Central

    Challacombe, Jean F.; Altherr, Michael R.; Xie, Gary; Bhotika, Smriti S.; Brown, Nancy; Bruce, David; Campbell, Connie S.; Campbell, Mary L.; Chen, Jin; Chertkov, Olga; Cleland, Cathy; Dimitrijevic, Mira; Doggett, Norman A.; Fawcett, John J.; Glavina, Tijana; Goodwin, Lynne A.; Green, Lance D.; Han, Cliff S.; Hill, Karen K.; Hitchcock, Penny; Jackson, Paul J.; Keim, Paul; Kewalramani, Avinash Ramesh; Longmire, Jon; Lucas, Susan; Malfatti, Stephanie; Martinez, Diego; McMurry, Kim; Meincke, Linda J.; Misra, Monica; Moseman, Bernice L.; Mundt, Mark; Munk, A. Christine; Okinaka, Richard T.; Parson-Quintana, B.; Reilly, Lee Philip; Richardson, Paul; Robinson, Donna L.; Saunders, Elizabeth; Tapia, Roxanne; Tesmer, Judith G.; Thayer, Nina; Thompson, Linda S.; Tice, Hope; Ticknor, Lawrence O.; Wills, Patti L.; Gilna, Paul; Brettin, Thomas S.

    2007-01-01

    Bacillus thuringiensis is an insect pathogen that is widely used as a biopesticide (E. Schnepf, N. Crickmore, J. Van Rie, D. Lereclus, J. Baum, J. Feitelson, D. R. Zeigler, and D. H. Dean, Microbiol. Mol. Biol. Rev. 62:775-806, 1998). Here we report the finished, annotated genome sequence of B. thuringiensis Al Hakam, which was collected in Iraq by the United Nations Special Commission (L. Radnedge, P. Agron, K. Hill, P. Jackson, L. Ticknor, P. Keim, and G. Andersen, Appl. Environ. Microbiol. 69:2755-2764, 2003). PMID:17337577

  3. Immunomodulatory drugs in AL amyloidosis.

    PubMed

    Jelinek, T; Kufova, Z; Hajek, R

    2016-03-01

    Immunoglobulin light chain amyloidosis (AL amyloidosis) is indeed a rare plasma cell disorder, yet the most common of the systemic amyloidoses. The choice of adequate treatment modality is complicated and depends dominantly on the risk stratification of these fragile patients. Immunomodulatory drugs (IMiDs) are currently used in newly diagnosed patients as well as in salvage therapy in relapsed/refractory patients. IMiDs have a pleiotropic effect on malignant cells and the exact mechanism of their action has been described recently. Thalidomide is the most ancient representative, effective but toxic. Lenalidomide seems to be more effective, nevertheless the toxicity remains high, especially in patients with renal insufficiency. Pomalidomide is the newest IMiD used in this indication with a good balance between efficacy and tolerable toxicity and represents the most promising compound. This review is focused on the evaluation of all three representatives of IMiDs and their roles in the treatment of this malignant disorder. PMID:26806146

  4. Instandhaltungsmanagement als Gestaltungsfeld Ganzheitlicher Produktionssysteme

    NASA Astrophysics Data System (ADS)

    Dombrowski, Uwe; Schulze, Sven; Otano, Isabel Crespo

    Sich kontinuierlich verändernde Rahmenbedingungen, wie beispielsweise eine steigende Variantenvielfalt, verkürzte Produktlebenszyklen sowie Kundenforderungen nach höherer Qualität, kürzeren Lieferzeiten und geringeren Kosten, fordern von produzierenden Unternehmen eine stetige Anpassung der Prozesse, der Organisation und der Strukturen. Seit den 90er Jahren versuchen immer mehr deutsche Unternehmen diesen veränderten Anforderungen mit der Einführung eines Ganzheitlichen Produktionssystems (GPS) zu begegnen. Ganzheitliche Produktionssysteme sind dabei in ihren Grundlagen an das Toyota Produktionssystem angelehnt, vereinigen aber auch weitere Methoden zu einem unternehmensspezifischen Regelwerk. Im Rahmen des langfristigen Trends zu unternehmensindividuellen Produktionssystemen wird sowohl in der Industrie als auch in der Forschung intensiv über das Toyota Produktionssystem, Lean Production, Lean Management und Ganzheitliche Produktionssysteme diskutiert, werden Konzepte zu Implementierung und Betrieb erstellt und die Wirtschaftlichkeit untersucht.

  5. Reactive Plasma Spraying of Fine Al2O3/AlN Feedstock Powder

    NASA Astrophysics Data System (ADS)

    Shahien, Mohammed; Yamada, Motohiro; Yasui, Toshiaki; Fukumoto, Masahiro

    2013-12-01

    Reactive plasma spraying (RPS) is a promising technology for in situ formation of aluminum nitride (AlN) coatings. Recently, AlN-based coatings were fabricated by RPS of alumina (Al2O3) powder in N2/H2 thermal plasma. This study investigated the feasibility of RPS of a fine Al2O3/AlN mixture and the influence of the plasma gases (N2, H2) on the nitriding conversion, and coating microstructure and properties. Thick AlN/Al2O3 coatings with high nitride content were successfully fabricated. The coatings consist of h-AlN, c-AlN, Al5O6N, γ-Al2O3, and a small amount of α-Al2O3. Use of fine particles enhanced the nitriding conversion and the melting tendency by increasing the surface area. Furthermore, the AlN additive improved the AlN content in the coatings. Increasing the N2 gas flow rate improved the nitride content and complete crystal growth to the h-AlN phase, and enhanced the coating thickness. On the other hand, though the H2 gas is required for plasma nitriding of the Al2O3 particles, increasing its flow rate decreased the nitride content and the coating thickness. Remarkable influence of the plasma gases on the coating composition, microstructure, and properties was observed during RPS of the fine particles.

  6. Al/Al-N/AlN compositional gradient film synthesized by ion-beam assisted deposition method

    SciTech Connect

    Amamoto, Yoshiki; Uchiyama, Shingo; Watanabe, Yoshihisa; Nakamura, Yoshikazu

    1997-12-01

    Al/Al-N-AlN compositional gradient thin film was deposited on a Si(100) substrate at room temperature by ion-beam assisted deposition method, with a diminishing ion beam current from 1.4 to 0 mA at increments of 0.3 mA in order to gradually decrease the nitrogen to aluminum ratio at the substrate. The gradual Al and AlN variation in composition was shown by the change of the Al/N atomic ratio analyzed by the energy dispersive X-ray spectroscopy (EDX) and the X-ray photoelectron spectroscopy (XPS) in the cross section of the film. The formation of crystalline Al metal and AlN ceramic layer on the Si substrate was revealed by X-ray diffraction (XRD). The cross sectional image taken by high resolution transmission electron microscope (HRTEM) showed a nano-sized crystalline Al-N ceramic material and the flat interface between the Si substrate and the AlN film.

  7. Accumulation of Al in Root Mucilage of an Al-Resistant and an Al-Sensitive Cultivar of Wheat.

    PubMed Central

    Archambault, D. J.; Zhang, G.; Taylor, G. J.

    1996-01-01

    To estimate rates of Al accumulation within the symplasm, all apoplastic pools of Al need to be eliminated or accounted for. We have developed a revised kinetic protocol that allows us to estimate the contribution of mucilage-bound Al to total, nonexchangeable Al, and to eliminate the mucilage as an apoplastic pool of Al. By comparing the Al content of excised root tips (2 cm) of wheat (Triticum aestivum L.) with and without the removal of the mucilage (using a 10-min wash in 1 M NH4Cl), we found that Al bound to the mucilage accounted for approximately 25 to 35% of Al remaining after desorption in citric acid. The kinetics of Al uptake into mucilage were biphasic, with a rapid phase occurring in the first 30 min of uptake, followed by a linear phase occurring in the remainder of the experimental period (180 min). By adopting a step for removal of mucilage into our existing kinetic protocol, we have been able to isolate a linear phase of uptake with only a slight deviation from linearity in the first 5 min. Although we cannot unambiguously identify this phase of uptake as uptake into the symplasm, we believe this new protocol provides us with the most accurate quantitative estimate of symplastic Al yet available. PMID:12226458

  8. The LOFAR radio environment

    NASA Astrophysics Data System (ADS)

    Offringa, A. R.; de Bruyn, A. G.; Zaroubi, S.; van Diepen, G.; Martinez-Ruby, O.; Labropoulos, P.; Brentjens, M. A.; Ciardi, B.; Daiboo, S.; Harker, G.; Jelić, V.; Kazemi, S.; Koopmans, L. V. E.; Mellema, G.; Pandey, V. N.; Pizzo, R. F.; Schaye, J.; Vedantham, H.; Veligatla, V.; Wijnholds, S. J.; Yatawatta, S.; Zarka, P.; Alexov, A.; Anderson, J.; Asgekar, A.; Avruch, M.; Beck, R.; Bell, M.; Bell, M. R.; Bentum, M.; Bernardi, G.; Best, P.; Birzan, L.; Bonafede, A.; Breitling, F.; Broderick, J. W.; Brüggen, M.; Butcher, H.; Conway, J.; de Vos, M.; Dettmar, R. J.; Eisloeffel, J.; Falcke, H.; Fender, R.; Frieswijk, W.; Gerbers, M.; Griessmeier, J. M.; Gunst, A. W.; Hassall, T. E.; Heald, G.; Hessels, J.; Hoeft, M.; Horneffer, A.; Karastergiou, A.; Kondratiev, V.; Koopman, Y.; Kuniyoshi, M.; Kuper, G.; Maat, P.; Mann, G.; McKean, J.; Meulman, H.; Mevius, M.; Mol, J. D.; Nijboer, R.; Noordam, J.; Norden, M.; Paas, H.; Pandey, M.; Pizzo, R.; Polatidis, A.; Rafferty, D.; Rawlings, S.; Reich, W.; Röttgering, H. J. A.; Schoenmakers, A. P.; Sluman, J.; Smirnov, O.; Sobey, C.; Stappers, B.; Steinmetz, M.; Swinbank, J.; Tagger, M.; Tang, Y.; Tasse, C.; van Ardenne, A.; van Cappellen, W.; van Duin, A. P.; van Haarlem, M.; van Leeuwen, J.; van Weeren, R. J.; Vermeulen, R.; Vocks, C.; Wijers, R. A. M. J.; Wise, M.; Wucknitz, O.

    2013-01-01

    Aims: This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods: We have analysed the radio-frequency interference (RFI) situation in two 24-h surveys with Dutch LOFAR stations, covering 30-78 MHz with low-band antennas and 115-163 MHz with high-band antennas. This is a subset of the full frequency range of LOFAR. The surveys have been observed with a 0.76 kHz/1 s resolution. Results: We measured the RFI occupancy in the low and high frequency sets to be 1.8% and 3.2% respectively. These values are found to be representative values for the LOFAR radio environment. Between day and night, there is no significant difference in the radio environment. We find that lowering the current observational time and frequency resolutions of LOFAR results in a slight loss of flagging accuracy. At LOFAR's nominal resolution of 0.76 kHz and 1 s, the false-positives rate is about 0.5%. This rate increases approximately linearly when decreasing the data frequency resolution. Conclusions: Currently, by using an automated RFI detection strategy, the LOFAR radio environment poses no perceivable problems for sensitive observing. It remains to be seen if this is still true for very deep observations that integrate over tens of nights, but the situation looks promising. Reasons for the low impact of RFI are the high spectral and time resolution of LOFAR; accurate detection methods; strong filters and high receiver linearity; and the proximity of the antennas to the ground. We discuss some strategies that can be used once low-level RFI starts to become apparent. It is important that the frequency range of LOFAR remains free of broadband interference, such as DAB stations and windmills.

  9. Enhanced resistive switching and multilevel behavior in bilayered HfAlO/HfAlO{sub x} structures for non-volatile memory applications

    SciTech Connect

    Faita, F. L.; Silva, J. P. B.; Pereira, M.; Gomes, M. J. M.

    2015-12-14

    In this work, hafnium aluminum oxide (HfAlO) thin films were deposited by ion beam sputtering deposition technique on Si substrate. The presence of oxygen vacancies in the HfAlO{sub x} layer deposited in oxygen deficient environment is evidenced from the photoluminescence spectra. Furthermore, HfAlO(oxygen rich)/HfAlO{sub x}(oxygen poor) bilayer structures exhibit multilevel resistive switching (RS), and the switching ratio becomes more prominent with increasing the HfAlO layer thickness. The bilayer structure with HfAlO/HfAlO{sub x} thickness of 30/40 nm displays the enhanced multilevel resistive switching characteristics, where the high resistance state/intermediate resistance state (IRS) and IRS/low resistance state resistance ratios are ≈10{sup 2} and ≈5 × 10{sup 5}, respectively. The switching mechanisms in the bilayer structures were investigated by the temperature dependence of the three resistance states. This study revealed that the multilevel RS is attributed to the coupling of ionic conduction and the metallic conduction, being the first associated to the formation and rupture of conductive filaments related to oxygen vacancies and the second with the formation of a metallic filament. Moreover, the bilayer structures exhibit good endurance and stability in time.

  10. Rotorcraft Conceptual Design Environment

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Sinsay, Jeffrey D.

    2010-01-01

    Requirements for a rotorcraft conceptual design environment are discussed, from the perspective of a government laboratory. Rotorcraft design work in a government laboratory must support research, by producing technology impact assessments and defining the context for research and development; and must support the acquisition process, including capability assessments and quantitative evaluation of designs, concepts, and alternatives. An information manager that will enable increased fidelity of analysis early in the design effort is described. This manager will be a framework to organize information that describes the aircraft, and enable movement of that information to and from analyses. Finally, a recently developed rotorcraft system analysis tool is described.

  11. Measuring the Natural Environment

    NASA Astrophysics Data System (ADS)

    Strangeways, Ian

    2003-11-01

    This new edition has been brought completely up-to-date and expanded considerably. It has five new chapters covering visibility, clouds, lightning, atmospheric composition, and the upper atmosphere. The chapter on barometric pressure has been rewritten and expanded, while the chapter on oceans and polar regions has been split into two separate and expanded chapters. In addition, the final chapter--Forward Look--has been rewritten. This volume will be important reading for all professionals involved in pure environmental research or in the day-to-day management of the environment. First Edition Hb (2000): 0-521-57310-6

  12. Aggregate and the environment

    USGS Publications Warehouse

    Langer, William H.; Drew, Lawrence J.; Sachs, J.S.

    2004-01-01

    This book is designed to help you understand our aggregate resources-their importance, where they come from, how they are processed for our use, the environmental concerns related to their mining and processing, how those concerns are addressed, and the policies and regulations designed to safeguard workers, neighbors, and the environment from the negative impacts of aggregate mining. We hope this understanding will help prepare you to be involved in decisions that need to be made-individually and as a society-to be good stewards of our aggregate resources and our living planet.

  13. Environment Conscious Ceramics (Ecoceramics)

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay; Levine, Stanley R. (Technical Monitor)

    2000-01-01

    Environment conscious ceramics (Ecoceramics) are a new class of materials, which can be produced with renewable natural resources (wood) or wood wastes (wood sawdust). Silicon carbide-based ecoceramics have been fabricated by reactive infiltration of carbonaceous preforms by molten silicon or silicon-refractory metal alloys. These carbonaceous preforms have been fabricated by pyrolysis of solid wood bodies at 1000 C. The fabrication approach, microstructure, and mechanical properties of SiC-based ecoceramics are presented. Ecoceramics have tailorable properties and behave like ceramic materials manufactured by conventional approaches.

  14. Synergistic interactions and environment

    SciTech Connect

    Myers, N. )

    1989-09-01

    This brief article describes synergistic interactions that would have a destructive impact on the environment: the role of chlorofluorocarbons linking the phenomena of ozone-layer depletion and the greenhouse effect; stresses on tropical forests (over-logging, agricultural settlement, and excess UV-B radiation due to ozone-layer depletion) that increase the susceptibility of the tract to injury from acid rain; increase in vulnerability to UV-B as a result of acid rain. Recognizing possible synergisms in advance may allow scientists to anticipate and even prevent some of the adverse repercussions.

  15. Environment sanitation handbook

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The environmental Sanitation handbook provides guidance in the implementation of the basic provisions of occupational medicine and environmental health programs to environmental sanitation. It presents methods and procedures useful for the control of those sanitation factors which could create discomfort and illness in man or do harm to his environment. The provisions of this handbook are applicable to all organizational elements of the Kennedy Space Center (KSC),NASA, and to its associated contractors located at KSC in accordance with the terms of their respective contracts.

  16. Rotorcraft Conceptual Design Environment

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Sinsay, Jeffrey

    2009-01-01

    Requirements for a rotorcraft conceptual design environment are discussed, from the perspective of a government laboratory. Rotorcraft design work in a government laboratory must support research, by producing technology impact assessments and defining the context for research and development; and must support the acquisition process, including capability assessments and quantitative evaluation of designs, concepts, and alternatives. An information manager that will enable increased fidelity of analysis early in the design effort is described. This manager will be a framework to organize information that describes the aircraft, and enable movement of that information to and from analyses. Finally, a recently developed rotorcraft system analysis tool is described.

  17. Particle Environment Package (PEP)

    NASA Astrophysics Data System (ADS)

    Barabash, S.; Wurz, P.; Brandt, P.; Wieser, M.; Holmström, M.; Futaana, Y.; Stenberg, G.; Nilsson, H.; Eriksson, A.; Tulej, M.; Vorburger, A.; Thomas, N.; Paranicas, C.; Mitchell, D. G.; Ho, G.; Mauk, B. H.; Haggerty, D.; Westlake, J. H.; Fränz, M.; Krupp, N.; Roussos, E.; Kallio, E.; Schmidt, W.; Szego, K.; Szalai, S.; Khurana, Krishan; Jia, Xianzhe; Paty, C.; Wimmer-Schweingruber, R. F.; Heber, B.; Kazushi, Asamura; Grande, M.; Lammer, H.; Zhang, T.; McKenna-Lawlor, S.; Krimigis, S. M.; Sarris, Th.; Grodent, D.

    2013-09-01

    Particle Environment Package (PEP) is a suite of particle sensors proposed for the ESA JUICE mission. PEP includes sensors for the comprehensive measurements of electrons, ions, energetic neutrals, and neutral gas. PEP covers over nine decades of energy <0.001 eV to >1 MeV with full angular coverage. Combining remote global imaging via energetic neutral atoms (ENAs) with in-situ measurements, PEP addresses all scientific objectives of the JUICE mission relevant to particle measurements. PEP will seek answers for four overarching science questions: How does the corotating magnetosphere of Jupiter interact with complex and diverse environment of Ganymede? How does the rapidly rotating magnetosphere of Jupiter interact with seemingly inert Callisto? What are the governing mechanisms and their global impact of release of material into the Jupiter magnetosphere from Europa and Io? How do internal and solar wind drivers cause such energetic, time variable and multi-scale phenomena in the steadily rotating giant magnetosphere of Jupiter? We discuss the suite's sensor basic design, performance, radiation mitigation principles and demonstrate how the suite fully addresses its scientific objectives.

  18. On representing chemical environments

    NASA Astrophysics Data System (ADS)

    Bartók, Albert P.; Kondor, Risi; Csányi, Gábor

    2013-05-01

    We review some recently published methods to represent atomic neighborhood environments, and analyze their relative merits in terms of their faithfulness and suitability for fitting potential energy surfaces. The crucial properties that such representations (sometimes called descriptors) must have are differentiability with respect to moving the atoms and invariance to the basic symmetries of physics: rotation, reflection, translation, and permutation of atoms of the same species. We demonstrate that certain widely used descriptors that initially look quite different are specific cases of a general approach, in which a finite set of basis functions with increasing angular wave numbers are used to expand the atomic neighborhood density function. Using the example system of small clusters, we quantitatively show that this expansion needs to be carried to higher and higher wave numbers as the number of neighbors increases in order to obtain a faithful representation, and that variants of the descriptors converge at very different rates. We also propose an altogether different approach, called Smooth Overlap of Atomic Positions, that sidesteps these difficulties by directly defining the similarity between any two neighborhood environments, and show that it is still closely connected to the invariant descriptors. We test the performance of the various representations by fitting models to the potential energy surface of small silicon clusters and the bulk crystal.

  19. The power of environment.

    PubMed

    Westbury, Becky

    2015-06-01

    In Ten tips for normal birth, the Royal College of Midwives (RCM) (2014) advocates the building of nests; creating an environment that helps women to feel safe and secure during birth, as this can improve women's experiences and likelihood of normal birth. Furthermore, a private, undisturbed and dark environment, where women feel calm and safe can promote the release of oxytocin, the hormone responsible for uterine contractions and thought to promote the release of the pain relieving hormones endorphins (Uvnas Moberg 2003). When this is not achieved, women can experience fear-tension-pain syndrome, impeding labour progress and causing increased levels of pain (Dick-Read 2013). In addition, birth space has the potential to encourage the promotion of normality through providing space to mobilise, and alternative furniture to enable upright birth positions. Midwives should help women to create a birth space in which they feel safe, calm and secure, to promote normality and increase the incidence of normal birth (RCM 2014). PMID:26320333

  20. Obesity and economic environments.

    PubMed

    Sturm, Roland; An, Ruopeng

    2014-01-01

    This review summarizes current understanding of economic factors during the obesity epidemic and dispels some widely held, but incorrect, beliefs. Rising obesity rates coincided with increases in leisure time (rather than increased work hours), increased fruit and vegetable availability (rather than a decline in healthier foods), and increased exercise uptake. As a share of disposable income, Americans now have the cheapest food available in history, which fueled the obesity epidemic. Weight gain was surprisingly similar across sociodemographic groups or geographic areas, rather than specific to some groups (at every point in time; however, there are clear disparities). It suggests that if one wants to understand the role of the environment in the obesity epidemic, one needs to understand changes over time affecting all groups, not differences between subgroups at a given time. Although economic and technological changes in the environment drove the obesity epidemic, the evidence for effective economic policies to prevent obesity remains limited. Taxes on foods with low nutritional value could nudge behavior toward healthier diets, as could subsidies/discounts for healthier foods. However, even a large price change for healthy foods could close only part of the gap between dietary guidelines and actual food consumption. Political support has been lacking for even moderate price interventions in the United States and this may continue until the role of environmental factors is accepted more widely. As opinion leaders, clinicians play an important role in shaping the understanding of the causes of obesity. PMID:24853237

  1. Geochemical Weathering in Glacial and Proglacial Environments

    NASA Astrophysics Data System (ADS)

    Tranter, M.

    2003-12-01

    It seems counterintuitive that chemical erosion in glaciated regions proceeds at rates comparable to those of temperate catchments with comparable specific runoff (Anderson et al., 1997). All the usual factors that are associated with elevated rates of chemical weathering ( Drever, 1988, 1994), such as water, soil, and vegetation, are either entirely absent or absent for much of the year. For example, glaciated regions are largely frozen for significant periods each year, the residence time of liquid water in the catchment is low ( Knight, 1999), there are thin, skeletal soils at best, and vegetation is either absent or limited ( French, 1997). Other chapters in this volume have highlighted how these factors are important in other, more temperate and tropical environments. Even so, chemical erosion rates in glaciated terrain are usually near to or greater than the continental average ( Sharp et al., 1995; Wadham et al., 1997; Hodson et al., 2000). This is because glaciated catchments usually have high specific runoff, there are high concentrations of freshly comminuted rock flour, which is typically silt sized and coated with microparticles, and adsorbed organic matter or surface precipitates that may hinder water-rock interactions are largely absent ( Tranter, 1982). In short, the rapid flow of water over fine-grained, recently crushed, reactive mineral surfaces maximizes both the potential rates of chemical weathering and chemical erosion.A range of both lab- and field-based studies of glacial chemical weathering have been undertaken, mainly on the smaller glaciers of Continental Europe (e.g., Brown et al., 1993a, b), Svalbard (e.g., Hodson et al., 2002), and North America (e.g., Anderson et al., 2000). The field-based studies typically generate hydrographs of glacier runoff, which show a characteristic diurnal cycle during summer in low latitudes ( Figure 1), and more subdued diurnal cycles at high latitudes (Figure 2 and Figure 3). The concentration of ions in

  2. Fabrication of Nb/AlO x/Al/AlO x/Nb junctions for voltage standard applications

    NASA Astrophysics Data System (ADS)

    Maezawa, M.; Urano, C.; Kaneko, N.; Kiryu, S.

    2007-10-01

    We present an overdamped superconductor-insulator-normal-insulator-superconductor (SINIS) junction technology for ac voltage standard applications. Modifying our standard Nb-junction process, we developed a simple process for Nb/AlOx/Al/AlOx/Nb-junction circuits. A Josephson arbitrary waveform synthesizer device which consisted of a 100-SINIS-junction array embedded in a 50 Ω coplanar waveguide was fabricated and successfully tested.

  3. Aluminum-Centered Tetrahedron-Octahedron Transition in Advancing Al-Sb-Te Phase Change Properties

    PubMed Central

    Xia, Mengjiao; Ding, Keyuan; Rao, Feng; Li, Xianbin; Wu, Liangcai; Song, Zhitang

    2015-01-01

    Group IIIA elements, Al, Ga, or In, etc., doped Sb-Te materials have proven good phase change properties, especially the superior data retention ability over popular Ge2Sb2Te5, while their phase transition mechanisms are rarely investigated. In this paper, aiming at the phase transition of Al-Sb-Te materials, we reveal a dominant rule of local structure changes around the Al atoms based on ab initio simulations and nuclear magnetic resonance evidences. By comparing the local chemical environments around Al atoms in respective amorphous and crystalline Al-Sb-Te phases, we believe that Al-centered motifs undergo reversible tetrahedron-octahedron reconfigurations in phase transition process. Such Al-centered local structure rearrangements significantly enhance thermal stability of amorphous phase compared to that of undoped Sb-Te materials, and facilitate a low-energy amorphization due to the weak links among Al-centered and Sb-centered octahedrons. Our studies may provide a useful reference to further understand the underlying physics and optimize performances of all IIIA metal doped Sb-Te phase change materials, prompting the development of NOR/NAND Flash-like phase change memory technology. PMID:25709082

  4. Aluminum-centered tetrahedron-octahedron transition in advancing Al-Sb-Te phase change properties.

    PubMed

    Xia, Mengjiao; Ding, Keyuan; Rao, Feng; Li, Xianbin; Wu, Liangcai; Song, Zhitang

    2015-01-01

    Group IIIA elements, Al, Ga, or In, etc., doped Sb-Te materials have proven good phase change properties, especially the superior data retention ability over popular Ge2Sb2Te5, while their phase transition mechanisms are rarely investigated. In this paper, aiming at the phase transition of Al-Sb-Te materials, we reveal a dominant rule of local structure changes around the Al atoms based on ab initio simulations and nuclear magnetic resonance evidences. By comparing the local chemical environments around Al atoms in respective amorphous and crystalline Al-Sb-Te phases, we believe that Al-centered motifs undergo reversible tetrahedron-octahedron reconfigurations in phase transition process. Such Al-centered local structure rearrangements significantly enhance thermal stability of amorphous phase compared to that of undoped Sb-Te materials, and facilitate a low-energy amorphization due to the weak links among Al-centered and Sb-centered octahedrons. Our studies may provide a useful reference to further understand the underlying physics and optimize performances of all IIIA metal doped Sb-Te phase change materials, prompting the development of NOR/NAND Flash-like phase change memory technology. PMID:25709082

  5. Aluminum-Centered Tetrahedron-Octahedron Transition in Advancing Al-Sb-Te Phase Change Properties

    NASA Astrophysics Data System (ADS)

    Xia, Mengjiao; Ding, Keyuan; Rao, Feng; Li, Xianbin; Wu, Liangcai; Song, Zhitang

    2015-02-01

    Group IIIA elements, Al, Ga, or In, etc., doped Sb-Te materials have proven good phase change properties, especially the superior data retention ability over popular Ge2Sb2Te5, while their phase transition mechanisms are rarely investigated. In this paper, aiming at the phase transition of Al-Sb-Te materials, we reveal a dominant rule of local structure changes around the Al atoms based on ab initio simulations and nuclear magnetic resonance evidences. By comparing the local chemical environments around Al atoms in respective amorphous and crystalline Al-Sb-Te phases, we believe that Al-centered motifs undergo reversible tetrahedron-octahedron reconfigurations in phase transition process. Such Al-centered local structure rearrangements significantly enhance thermal stability of amorphous phase compared to that of undoped Sb-Te materials, and facilitate a low-energy amorphization due to the weak links among Al-centered and Sb-centered octahedrons. Our studies may provide a useful reference to further understand the underlying physics and optimize performances of all IIIA metal doped Sb-Te phase change materials, prompting the development of NOR/NAND Flash-like phase change memory technology.

  6. Inverse modelling of radionuclide release rates using gamma dose rate observations

    NASA Astrophysics Data System (ADS)

    Hamburger, Thomas; Evangeliou, Nikolaos; Stohl, Andreas; von Haustein, Christoph; Thummerer, Severin; Wallner, Christian

    2015-04-01

    inversion method uses a Bayesian formulation considering uncertainties for the a priori source term and the observations (Eckhardt et al., 2008, Stohl et al., 2012). The a priori information on the source term is a first guess. The gamma dose rate observations are used to improve the first guess and to retrieve a reliable source term. The details of this method will be presented at the conference. This work is funded by the Bundesamt für Strahlenschutz BfS, Forschungsvorhaben 3612S60026. References Davoine, X. and Bocquet, M., Atmos. Chem. Phys., 7, 1549-1564, 2007. Devell, L., et al., OCDE/GD(96)12, 1995. Eckhardt, S., et al., Atmos. Chem. Phys., 8, 3881-3897, 2008. Saunier, O., et al., Atmos. Chem. Phys., 13, 11403-11421, 2013. Stohl, A., et al., Atmos. Environ., 32, 4245-4264, 1998. Stohl, A., et al., Atmos. Chem. Phys., 5, 2461-2474, 2005. Stohl, A., et al., Atmos. Chem. Phys., 12, 2313-2343, 2012.

  7. Inverse modelling of radionuclide release rates using gamma dose rate observations

    NASA Astrophysics Data System (ADS)

    Hamburger, Thomas; Stohl, Andreas; von Haustein, Christoph; Thummerer, Severin; Wallner, Christian

    2014-05-01

    relatively sparse grid and the temporal resolution of available data may be low within the order of hours or a day. Gamma dose rates on the other hand are observed routinely on a much denser grid and higher temporal resolution. Gamma dose rate measurements contain no explicit information on the observed spectrum of radionuclides and have to be interpreted carefully. Nevertheless, they provide valuable information for the inverse evaluation of the source term due to their availability (Saunier et al., 2013). We present a new inversion approach combining an atmospheric dispersion model and observations of radionuclide activity concentrations and gamma dose rates to obtain the source term of radionuclides. We use the Lagrangian particle dispersion model FLEXPART (Stohl et al., 1998; Stohl et al., 2005) to model the atmospheric transport of the released radionuclides. The gamma dose rates are calculated from the modelled activity concentrations. The inversion method uses a Bayesian formulation considering uncertainties for the a priori source term and the observations (Eckhardt et al., 2008). The a priori information on the source term is a first guess. The gamma dose rate observations will be used with inverse modelling to improve this first guess and to retrieve a reliable source term. The details of this method will be presented at the conference. This work is funded by the Bundesamt für Strahlenschutz BfS, Forschungsvorhaben 3612S60026. References Davoine, X. and Bocquet, M., Atmos. Chem. Phys., 7, 1549-1564, 2007. Devell, L., et al., OCDE/GD(96)12, 1995. Eckhardt, S., et al., Atmos. Chem. Phys., 8, 3881-3897, 2008. Saunier, O., et al., Atmos. Chem. Phys., 13, 11403-11421, 2013. Stohl, A., et al., Atmos. Environ., 32, 4245-4264, 1998. Stohl, A., et al., Atmos. Chem. Phys., 5, 2461-2474, 2005. Stohl, A., et al., Atmos. Chem. Phys., 12, 2313-2343, 2012.

  8. Effects of Volcanoes on the Natural Environment

    NASA Technical Reports Server (NTRS)

    Mouginis-Mark, Peter J.

    2005-01-01

    The primary focus of this project has been on the development of techniques to study the thermal and gas output of volcanoes, and to explore our options for the collection of vegetation and soil data to enable us to assess the impact of this volcanic activity on the environment. We originally selected several volcanoes that have persistent gas emissions and/or magma production. The investigation took an integrated look at the environmental effects of a volcano. Through their persistent activity, basaltic volcanoes such as Kilauea (Hawaii) and Masaya (Nicaragua) contribute significant amounts of sulfur dioxide and other gases to the lower atmosphere. Although primarily local rather than regional in its impact, the continuous nature of these eruptions means that they can have a major impact on the troposphere for years to decades. Since mid-1986, Kilauea has emitted about 2,000 tonnes of sulfur dioxide per day, while between 1995 and 2000 Masaya has emotted about 1,000 to 1,500 tonnes per day (Duffel1 et al., 2001; Delmelle et al., 2002; Sutton and Elias, 2002). These emissions have a significant effect on the local environment. The volcanic smog ("vog" ) that is produced affects the health of local residents, impacts the local ecology via acid rain deposition and the generation of acidic soils, and is a concern to local air traffic due to reduced visibility. Much of the work that was conducted under this NASA project was focused on the development of field validation techniques of volcano degassing and thermal output that could then be correlated with satellite observations. In this way, we strove to develop methods by which not only our study volcanoes, but also volcanoes in general worldwide (Wright and Flynn, 2004; Wright et al., 2004). Thus volcanoes could be routinely monitored for their effects on the environment. The selected volcanoes were: Kilauea (Hawaii; 19.425 N, 155.292 W); Masaya (Nicaragua; 11.984 N, 86.161 W); and Pods (Costa Rica; 10.2OoN, 84.233 W).

  9. Geomorphic changes in Ras Al-Subiyah area, Kuwait

    NASA Astrophysics Data System (ADS)

    Al Hurban, A.; El-Gamily, H.; El-Sammak, A.

    2008-06-01

    The Ras Al-Subiyah area is considered one of the most promising areas in Kuwait for future development. This development will include a new town called Subiyah and its associated infrastructure. This area is also being considered as the location for connection between Boubyan Island, which is now undergoing major development and the Kuwait mainland. The present study investigates the geomorphology of the Ras Al-Sabiyah area in the northern sector of Kuwait. The study area is generally flat, and it is located west of the Jal Az-Zor escarpment. It is bordered on the east by the Khor Al-Sabiyah tidal channel and on the south by Kuwait Bay. The area receives sediments from several sources; currently the most important are aeolian sediments and the deposition of mud delivered through the Khor Al-Sabiyah from the Iraqi marshes. The study area has been subjected to severe environmental changes due to the Gulf wars and the drainage of Iraqi marshes and the associated artificial changes in fluvial system. Twenty-two surface sediments were collected from the Ras Al-Subiyah area. Samples were collected to include the main geomorphologic characteristic features of the study area. Field observations and remote sensing images from 1990 and 2001 were used to produce an updated geomorphologic map for the Ras Al-Subiyah and a map showing geomorphic changes between 1990 and 2001. Grain size of the surface sediment ranges from gravel to medium sand. In general, grain size statistical analysis indicates that most of the areas are composed of two or more classes of sands transported and deposited from different sources including aeolian, sabkhas, river and the bays. The variability in the grain size statistical parameters may be attributed to the complexity of surface morphology as well as the diversity in the type of depositional environment in the Ras Al-Subiyah area. The total area subjected to change during the 12-year period (1990 2001) is about 32 km2 as calculated using GIS

  10. Growth and stress-induced transformation of zinc blende AlN layers in Al-AlN-TiN multilayers

    SciTech Connect

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; Liu, Xiang -Yang; Misra, Amit

    2015-12-18

    We report that AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN.

  11. Growth and Stress-induced Transformation of Zinc blende AlN Layers in Al-AlN-TiN Multilayers

    PubMed Central

    Li, Nan; Yadav, Satyesh K.; Wang, Jian; Liu, Xiang-Yang; Misra, Amit

    2015-01-01

    AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN. PMID:26681109

  12. Growth and Stress-induced Transformation of Zinc blende AlN Layers in Al-AlN-TiN Multilayers.

    PubMed

    Li, Nan; Yadav, Satyesh K; Wang, Jian; Liu, Xiang-Yang; Misra, Amit

    2015-01-01

    AlN nanolayers in sputter deposited {111}Al/AlN/TiN multilayers exhibit the metastable zinc-blende-structure (z-AlN). Based on density function theory calculations, the growth of the z-AlN is ascribed to the kinetically and energetically favored nitridation of the deposited aluminium layer. In situ nanoindentation of the as-deposited {111}Al/AlN/TiN multilayers in a high-resolution transmission electron microscope revealed the z-AlN to wurzite AlN phase transformation through collective glide of Shockley partial dislocations on every two {111} planes of the z-AlN. PMID:26681109

  13. Phase stability of LiAlO{sub 2} in molten carbonate

    SciTech Connect

    Tomimatsu, N.; Ohzu, H.; Akasaka, Y.; Nakagawa, K.

    1997-12-01

    In current molten carbonate fuel cells (MCFCs), submicron {gamma}-LiAlO{sub 2} powder is used as the electrolyte-retaining material because of its stability at high temperatures. However, it is recognized that {gamma}-LiAlO{sub 2} transforms to mainly {alpha}-LiAlO{sub 2} during MCFC operation. This suggests that {gamma}-LiAlO{sub 2} behavior in molten carbonate is different from that in air. To confirm the stable allotropic phase under actual MCFC conditions, the authors investigated the phase transformation of LiAlO{sub 2} in the presence of molten carbonate. It was found that essentially the {alpha}-phase is stable in a low-temperature and high-p{sub CO{sub 2}} environment, whereas the {gamma}-phase is stable in a high-temperature and low-p{sub CO{sub 2}} environment. In addition, there exists relative particle size dependence of the allotropic transformation when {alpha}- and {gamma}-LiAlO{sub 2} powders coexist. Further, the authors confirmed that the phase composition and structure of a matrix which consists of the {alpha}-LiAlO{sub 2} powder is stable up to 7,550 h at 700 C when the powder particle diameter is 0.3 {micro}m. These results suggest that {alpha}-LiAlO{sub 2} powder with 0.3 {micro}m diam is preferred over conventional {gamma}-LiAlO{sub 2} powder as an electrolyte-retaining material in MCFCs.

  14. Space Environments Testbed

    NASA Technical Reports Server (NTRS)

    Leucht, David K.; Koslosky, Marie J.; Kobe, David L.; Wu, Jya-Chang C.; Vavra, David A.

    2011-01-01

    The Space Environments Testbed (SET) is a flight controller data system for the Common Carrier Assembly. The SET-1 flight software provides the command, telemetry, and experiment control to ground operators for the SET-1 mission. Modes of operation (see dia gram) include: a) Boot Mode that is initiated at application of power to the processor card, and runs memory diagnostics. It may be entered via ground command or autonomously based upon fault detection. b) Maintenance Mode that allows for limited carrier health monitoring, including power telemetry monitoring on a non-interference basis. c) Safe Mode is a predefined, minimum power safehold configuration with power to experiments removed and carrier functionality minimized. It is used to troubleshoot problems that occur during flight. d) Operations Mode is used for normal experiment carrier operations. It may be entered only via ground command from Safe Mode.

  15. Lighting the office environment

    SciTech Connect

    Lamarre, L.

    1995-05-01

    Now that the video display terminal is as common as the telephone in office environments, properly lighting these spaces has become a critical task. Over illumination-the most common problem-can create glare and reflections on computer screens and generate too much contrast between a VDT and the surrounding area. Not only do such effects make work more difficult to complete, but they can also make workers uncomfortable, causing headaches, weariness, and other problems that affect well-being and productivity. An EPRI collaboration with Lightolier has resulted in a new line of luminaires and controls especially designed for use with VDTs. Adding to the attractiveness of these lighting systems are their energy efficiency and a single-source warranty. This paper discusses this energy effective lighting, products, and controls.

  16. Life in Extreme Environments

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn; Bray, James A. (Technical Monitor)

    2002-01-01

    Each recent report of liquid water existing elsewhere in the solar system has reverberated through the international press and excited the imagination of humankind. Why? Because in the last few decades we have come to realize that where there is liquid water on Earth, virtually no matter what the physical conditions, there is life. What we previously thought of as insurmountable physical and chemical barriers to life, we now see as yet another niche harboring 'extremophiles'. This realization, coupled with new data on the survival of microbes in the space environment and modeling of the potential for transfer of life between celestial bodies, suggests that life could be more common than previously thought. Here we critically examine what it means to be an extremophile, the implications of this for evolution, biotechnology, and especially the search for life in the cosmos.

  17. Radiation Environment Inside Spacecraft

    NASA Technical Reports Server (NTRS)

    O'Neill, Patrick

    2015-01-01

    Dr. Patrick O'Neill, NASA Johnson Space Center, will present a detailed description of the radiation environment inside spacecraft. The free space (outside) solar and galactic cosmic ray and trapped Van Allen belt proton spectra are significantly modified as these ions propagate through various thicknesses of spacecraft structure and shielding material. In addition to energy loss, secondary ions are created as the ions interact with the structure materials. Nuclear interaction codes (FLUKA, GEANT4, HZTRAN, MCNPX, CEM03, and PHITS) transport free space spectra through different thicknesses of various materials. These "inside" energy spectra are then converted to Linear Energy Transfer (LET) spectra and dose rate - that's what's needed by electronics systems designers. Model predictions are compared to radiation measurements made by instruments such as the Intra-Vehicular Charged Particle Directional Spectrometer (IV-CPDS) used inside the Space Station, Orion, and Space Shuttle.

  18. Visual Computing Environment Workshop

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles (Compiler)

    1998-01-01

    The Visual Computing Environment (VCE) is a framework for intercomponent and multidisciplinary computational simulations. Many current engineering analysis codes simulate various aspects of aircraft engine operation. For example, existing computational fluid dynamics (CFD) codes can model the airflow through individual engine components such as the inlet, compressor, combustor, turbine, or nozzle. Currently, these codes are run in isolation, making intercomponent and complete system simulations very difficult to perform. In addition, management and utilization of these engineering codes for coupled component simulations is a complex, laborious task, requiring substantial experience and effort. To facilitate multicomponent aircraft engine analysis, the CFD Research Corporation (CFDRC) is developing the VCE system. This system, which is part of NASA's Numerical Propulsion Simulation System (NPSS) program, can couple various engineering disciplines, such as CFD, structural analysis, and thermal analysis.

  19. LDEF environment modeling updates

    NASA Technical Reports Server (NTRS)

    Gordon, Tim; Rantanen, Ray; Whitaker, Ann F.

    1995-01-01

    An updated gas dynamics model for gas interactions around the LDEF is presented that includes improved scattering algorithms. The primary improvement is more accurate predictions of surface fluxes in the wake region. The code used is the Integrated Spacecraft Environments Model (ISEM). Additionally, initial results of a detailed ISEM prediction model of the Solar Array Passive LDEF Experiment (SAMPLE), A0171, is presented. This model includes details of the A0171 geometry and outgassing characteristics of the many surfaces on the experiment. The detailed model includes the multiple scattering that exists between the ambient atmosphere, LDEF outgassing, and atomic oxygen erosion products. Predictions are made for gas densities, surface fluxes and deposition at three different time periods of the LDEF mission.

  20. MIPs in Aqueous Environments.

    PubMed

    Wan, Ying-chun; Ma, Hui-ting; Lu, Bin

    2015-01-01

    When organic solvent-compatible molecularly imprinted polymers (MIPs) are used in aqueous environment, how to reduce nonspecific binding is a major challenge. By modifying the binding solvents and introducing appropriate washing and elution steps, even relatively hydrophobic MIPs can gain optimal rebinding selectivity in aqueous conditions. Furthermore, water-compatible MIPs that can be used to treat aqueous samples directly have been prepared. The use of hydrophilic co-monomers, the controlled surface modification through controlled radical polymerization, and the new interfacial molecular imprinting methods are different strategies to prepare water-compatible MIPs. By combining MIPs with other techniques, both organic solvent-compatible and water-compatible MIPs can display better functional performances in aqueous conditions. Intensive studies on MIPs in aqueous conditions can provide new MIPs with much-improved compatibilities that will lead to more interesting applications in biomedicine and biotechnology. PMID:25796623

  1. Ceres water regime: surface temperature, water sublimation and transient exo(atmo)sphere

    NASA Astrophysics Data System (ADS)

    Formisano, M.; De Sanctis, M. C.; Magni, G.; Federico, C.; Capria, M. T.

    2016-01-01

    Recent observations of water emission around Ceres suggest the presence of an ice layer on or beneath the surface of this asteroid. Several mechanisms have been suggested to explain these plumes, among which cometary-like sublimation seems to be plausible, since there is a correlation between the magnitude of the emission and the change in the heliocentric distance along the orbit. In this work, we applied a comet sublimation model to study the plausible scenarios that match with Herschel observations of the water flux (1026 molecules s-1). Each scenario is characterized by a well-defined set of physical and orbital parameters. Moreover, a study of the dynamic evolution of the H2O plume has been performed, showing that an optically thin transient atmospheric envelope, with a typical timescale of some tens of days, can be maintained by the H2O surface emission. Our simulations could be useful theoretical support for the Dawn NASA mission by giving a better understanding of the physical conditions for water sublimation and ice stability.

  2. Improving coherence with nested environments

    NASA Astrophysics Data System (ADS)

    Moreno, H. J.; Gorin, T.; Seligman, T. H.

    2015-09-01

    We have in mind a register of qubits for an quantum information system, and consider its decoherence in an idealized but typical situation. Spontaneous decay and other couplings to the far environment, considered as the world outside the quantum apparatus, will be neglected, while couplings to quantum states within the apparatus, i.e., to a near environment, are assumed to dominate. Thus the central system couples to the near environment, which in turn couples to a far environment. Considering that the dynamics in the near environment is not sufficiently well known or controllable, we shall use random matrix methods to obtain analytic results. We consider a simplified situation where the central system suffers weak dephasing from the near environment, which in turn is coupled randomly to the far environment. We find the anti-intuitive result that increasing the coupling between the near and far environment actually protects the central qubit.

  3. Environment and the skin.

    PubMed

    Suskind, R R

    1977-10-01

    The skin is an important interface between man and his environment; it is an important portal of entry for hazardous agents and a vulnerable target tissue as well. It is a uniquely accessible model system for detecting hazards and for studying mechanisms of a wide variety of biologic funcitons. Environmental causes of skin reactions comprise a vast array of physical, chemical and biological agents. To appreciate the role of the skin as an interface with man's environment, it is necessary to understand the multiple adaptive mechanisms, and the defenses of the skin against the environmental stresses. The skin is endowed with a versatile group of defenses against penetration, fluid loss from the body, thermal stress, solar radiation, physical trauma and microbial agents. Patterns of adverse response range in quality and intensity from uncomplicated itching to metastatic neoplasia. Environmental problems comprise a large segment of disabling skin disease. Although critical epidemiologic data is limited, cutaneous illnesses comprise a significant segment of occupational disease. This represents a significant loss in productivity and a major cause of disability. The most serious research needs include the development of surveillance systems for identifying skin hazards and determining frequency of environmental skin disease; the development of new models for studying cutaneous penetration; the elucidation of the mechanisms of nonallergic inflammatory reactions (primary irritation) and of the accommodation phenomenon; the development of more sensitive models for predicting adverse responses to marginal irritants; the utilization of modern skills of immunobiology and immunochemistry to elucidate mechanisms of allergic responses; the launching of epidemiologic studies to determine the long term effects of PCBs and associated compounds such as dioxins; and the expansion of research in the mechanisms of skin cancer in relation to susceptibility, genetic and metabolic

  4. Environment and the skin

    PubMed Central

    Suskind, Raymond R.

    1977-01-01

    The skin is an important interface between man and his environment; it is an important portal of entry for hazardous agents and a vulnerable target tissue as well. It is a uniquely accessible model system for detecting hazards and for studying mechanisms of a wide variety of biologic funcitons. Environmental causes of skin reactions comprise a vast array of physical, chemical and biological agents. To appreciate the role of the skin as an interface with man's environment, it is necessary to understand the multiple adaptive mechanisms, and the defenses of the skin against the environmental stresses. The skin is endowed with a versatile group of defenses against penetration, fluid loss from the body, thermal stress, solar radiation, physical trauma and microbial agents. Patterns of adverse response range in quality and intensity from uncomplicated itching to metastatic neoplasia. Environmental problems comprise a large segment of disabling skin disease. Although critical epidemiologic data is limited, cutaneous illnesses comprise a significant segment of occupational disease. This represents a significant loss in productivity and a major cause of disability. The most serious research needs include the development of surveillance systems for identifying skin hazards and determining frequency of environmental skin disease; the development of new models for studying cutaneous penetration; the elucidation of the mechanisms of nonallergic inflammatory reactions (primary irritation) and of the accommodation phenomenon; the development of more sensitive models for predicting adverse responses to marginal irritants; the utilization of modern skills of immunobiology and immunochemistry to elucidate mechanisms of allergic responses; the launching of epidemiologic studies to determine the long term effects of PCBs and associated compounds such as dioxins; and the expansion of research in the mechanisms of skin cancer in relation to susceptibility, genetic and metabolic

  5. Enterprise data environment

    SciTech Connect

    Ricketts, B.

    1994-12-31

    This paper will report the progress of M3i`s evaluation of the communication challenges facing their client base and offer evidence that the puzzle is about to be solved. This paper will introduce the Enterprise Data Environment. In order to create a basis for Enterprise Data Environment (EDE), the fundamental data bases created and maintained by an average electrical utility must be discussed. The AM/FM industry began almost 30 years ago while the first {open_quotes}fast-pencil{close_quotes} system dates back to the 1960`s. The industry, which has undergone a series of transitions and name changes over the years, had its beginning as Computer Aided Drafting (CAD). As the name suggests, the technology drew lines and circles and was a tool for a draftsperson. One extension to CAD was Computer Assisted Mapping (CAD/CAM). This extension to CAD led to the creation of maps and was the technology renamed Automated Mapping (AM). One of the reasons for the name change was CAM also stood for Computer Aided Manufacturing. When data bases became more robust and popular (in the 1970`s), the natural extension to CAM (Computer Assisted Mapping) was to add a data base of the structures and facilities represented on the maps. Since data bases are managed, the technology was logically called Facilities Management (FM). Hence, Automated Mapping/Facilities Management or AM/FM. It is also called Geographic Information Systems or GIS. The main problem with AM/FM is that the data bases are created, maintained and updated by draftspersons from the AM perspective. Traditionally, these data bases have been as much as six months out-of-date. Because a utility relies on up-to-date data, it might be wondered how any work was achieved with AM/FM.

  6. GLobal Integrated Design Environment

    NASA Technical Reports Server (NTRS)

    Kunkel, Matthew; McGuire, Melissa; Smith, David A.; Gefert, Leon P.

    2011-01-01

    The GLobal Integrated Design Environment (GLIDE) is a collaborative engineering application built to resolve the design session issues of real-time passing of data between multiple discipline experts in a collaborative environment. Utilizing Web protocols and multiple programming languages, GLIDE allows engineers to use the applications to which they are accustomed in this case, Excel to send and receive datasets via the Internet to a database-driven Web server. Traditionally, a collaborative design session consists of one or more engineers representing each discipline meeting together in a single location. The discipline leads exchange parameters and iterate through their respective processes to converge on an acceptable dataset. In cases in which the engineers are unable to meet, their parameters are passed via e-mail, telephone, facsimile, or even postal mail. The result of this slow process of data exchange would elongate a design session to weeks or even months. While the iterative process remains in place, software can now exchange parameters securely and efficiently, while at the same time allowing for much more information about a design session to be made available. GLIDE is written in a compilation of several programming languages, including REALbasic, PHP, and Microsoft Visual Basic. GLIDE client installers are available to download for both Microsoft Windows and Macintosh systems. The GLIDE client software is compatible with Microsoft Excel 2000 or later on Windows systems, and with Microsoft Excel X or later on Macintosh systems. GLIDE follows the Client-Server paradigm, transferring encrypted and compressed data via standard Web protocols. Currently, the engineers use Excel as a front end to the GLIDE Client, as many of their custom tools run in Excel.

  7. [Environment: the other disaster].

    PubMed

    Acevi

    The arid conditions started in the Sahel of Africa around 1960, but no attention was paid partly because of the low population size (1/2 of the 1990 figure), low level of urbanization, and inadequate social development. Development projects have contributed to the acceleration of the degradation of natural resources and to increasing pollution. At that time the alarming rate of desertification could not be proven by satellite photography, nor was enough known about the progression of global climate changes. A committee to combat Sahelian desertification was established only in 1970. The forces of desertification are controlled by the rainfall regularly deposited by the intertropical front which has receded 1000-1500 km in the last 10,000 years. In the last 20 years precipitation has decreased by 20% in Niamey, Niger. Contributory factors are the increase of temperature, the reduction of cloud masses, carbon gas emissions from human activities, deforestation for agriculture, construction, industrialization, and pollution from toxic chemicals. Development programs have resulted in the diversion of water volumes draining the Sahelian Nile and Niger valleys. Increased population and misguided government policies have increased socioeconomic pressures on the environment. The 1st plans to fight desertification were developed during 1984-1987. Effecting change, however, means a change of mentality. The objectives are food self-sufficiency by rehabilitation and utilization of the productive potential of water, soil, and human know-how; the preservation of the environment; a credible birth control policy; and promotion of small-scale integrated projects of 500-1500 and 10-2500 hectares depending on regions. The most threatened zones receive 250-400 mm of rain whose fate in the next 50 years is crucial. PMID:12285742

  8. Environment and alternative development

    SciTech Connect

    Kothari, R.

    1980-01-01

    This global review stresses the present-day human predicament, marked by the inequity of simultaneous material abundance and overdevelopment in some regions or sections and underdevelopment, increasing poverty, and deprivation in some others. It seeks to examine the dynamics of a global structure that forces a continual flow of resources away from non-industrialized into industrialized countries, and from a steady and sustainable to an accelerating use and rapacious use of resources in the service of a wasteful life-style that is now spreading to the developing countries. The science and technology that sets this process in motion and sustains it leads to the domination of man by machine, blights the life chances of future generations, and posits development and environment in an adversary relationship. The paper examines the philosophical, historical, cultural and ethnic underpinnings of modern science and technology and points to the urgent need for rediscovering the other traditions that take an integrated and holistic view of life as a whole, in which science and technology and development and environment all merge in a symbiotic relationship. This entails the search for an alternative concept of both development and technology as well as of life-styles, so as to ensure diversity in consonance with local resource endowments (human, material and technical), foster self-reliance and autonomy, and promote equity and participation, not only in economic and political processes, but also in giving meaning and content to human dignity at various levels. At the end, the paper spells out the policy implications of such an approach.

  9. CAPS Simulation Environment Development

    NASA Technical Reports Server (NTRS)

    Murphy, Douglas G.; Hoffman, James A.

    2005-01-01

    The final design for an effective Comet/Asteroid Protection System (CAPS) will likely come after a number of competing designs have been simulated and evaluated. Because of the large number of design parameters involved in a system capable of detecting an object, accurately determining its orbit, and diverting the impact threat, a comprehensive simulation environment will be an extremely valuable tool for the CAPS designers. A successful simulation/design tool will aid the user in identifying the critical parameters in the system and eventually allow for automatic optimization of the design once the relationships of the key parameters are understood. A CAPS configuration will consist of space-based detectors whose purpose is to scan the celestial sphere in search of objects likely to make a close approach to Earth and to determine with the greatest possible accuracy the orbits of those objects. Other components of a CAPS configuration may include systems for modifying the orbits of approaching objects, either for the purpose of preventing a collision or for positioning the object into an orbit where it can be studied or used as a mineral resource. The Synergistic Engineering Environment (SEE) is a space-systems design, evaluation, and visualization software tool being leveraged to simulate these aspects of the CAPS study. The long-term goal of the SEE is to provide capabilities to allow the user to build and compare various CAPS designs by running end-to-end simulations that encompass the scanning phase, the orbit determination phase, and the orbit modification phase of a given scenario. Herein, a brief description of the expected simulation phases is provided, the current status and available features of the SEE software system is reported, and examples are shown of how the system is used to build and evaluate a CAPS detection design. Conclusions and the roadmap for future development of the SEE are also presented.

  10. Reply to Vance et al.

    SciTech Connect

    Woon-Chee Yee; Elliott, J.L; Kwon, J.M.; Goodfellow, P.

    1996-07-01

    In our report of a family with a motor and sensory polyneuropathy that was linked to chromosome 3q, we classified this neuropathy as a form of hereditary motor and sensory neuropathy II (HMSN II, also known as {open_quotes}CMT2{close_quotes}). Doubts have been raised by Vance et al. as to whether this neuropathy should be classified as hereditary sensory autonomic neuropathy I (HSAN I) instead of HMSN II. While it is reasonable to raise such doubts, we believe that the neuropathy is best designated as HMSN II for the reasons described below. The group of disorders described as HSAN are characterized by primary or predominant involvement of sensory and autonomic neurons that fail to develop or that undergo atrophy and degeneration. These disorders were extensively reviewed by Dyck and Ohta, who initially described them as the hereditary sensory neuropathies (HSN). It was Dyck who subsequently suggested that these disorders be designated HSAN rather than HSN, because of the presence of autonomic involvement. 8 refs.

  11. Effects of Al Contents on Carburization Behavior and Corrosion Resistance of TiAl Alloys

    NASA Astrophysics Data System (ADS)

    Liao, Cui Jiao; He, Yue Hui; Ming, Xing Zu

    2015-10-01

    TiAl alloys with Al contents of 30.7, 37, 46.5, and 54.2 at.% were carburized. Corrosion resistance of the untreated and the carburized TiAl alloys was comparatively analyzed. The phase and microstructure of the carburized TiAl alloys were studied by x-ray diffraction and scanning electron microscopy, respectively. Electrochemical corrosion behavior of the untreated and the carburized TiAl alloys was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy. Experimental results indicate that different Al contents bring about distinct microstructure of the carburized layers. The lower Al content leads to the formation of the thicker binary carbides and the thinner Ti2AlC phase. Additionally, the lower Al content leads to higher corrosion resistance in the untreated and the carburized states.

  12. Orientation relationship of eutectoid FeAl and FeAl2

    PubMed Central

    Scherf, A.; Kauffmann, A.; Kauffmann-Weiss, S.; Scherer, T.; Li, X.; Stein, F.; Heilmaier, M.

    2016-01-01

    Fe–Al alloys in the aluminium range of 55–65 at.% exhibit a lamellar microstructure of B2-ordered FeAl and triclinic FeAl2, which is caused by a eutectoid decomposition of the high-temperature Fe5Al8 phase, the so-called ∊ phase. The orientation relationship of FeAl and FeAl2 has previously been studied by Bastin et al. [J. Cryst. Growth (1978 ▸), 43, 745] and Hirata et al. [Philos. Mag. Lett. (2008 ▸), 88, 491]. Since both results are based on different crystallographic data regarding FeAl2, the data are re-evaluated with respect to a recent re-determination of the FeAl2 phase provided by Chumak et al. [Acta Cryst. (2010 ▸), C66, i87]. It is found that both orientation relationships match subsequent to a rotation operation of 180° about a 〈112〉 crystallographic axis of FeAl or by applying the inversion symmetry of the FeAl2 crystal structure as suggested by the Chumak data set. Experimental evidence for the validity of the previously determined orientation relationships was found in as-cast fully lamellar material (random texture) as well as directionally solidified material (∼〈110〉FeAl || solidification direction) by means of orientation imaging microscopy and global texture measurements. In addition, a preferential interface between FeAl and FeAl2 was identified by means of trace analyses using cross sectioning with a focused ion beam. On the basis of these habit planes the orientation relationship between the two phases can be described by (01)FeAl || (114) and [111]FeAl || [10]. There is no evidence for twinning within FeAl lamellae or alternating orientations of FeAl lamellae. Based on the determined orientation and interface data, an atomistic model of the structure relationship of Fe5Al8, FeAl and FeAl2 in the vicinity of the eutectoid decomposition is derived. This model is analysed with respect to the strain which has to be accommodated at the interface of FeAl and FeAl2. PMID:27047304

  13. 75 FR 16518 - Florida Power Corporation, et al.; Crystal River Unit 3 Nuclear Generating Plant; Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-01

    ... FR 13926- 13993), effective May 26, 2009, with a full implementation date of March 31, 2010, requires... have a significant effect on the quality of the human environment (75 FR 13320, dated March 19, 2010... COMMISSION Florida Power Corporation, et al.; Crystal River Unit 3 Nuclear Generating Plant; Exemption...

  14. 75 FR 70953 - Florida Power Corporation, et al.; Crystal River Unit 3 Nuclear Generating Plant; Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-19

    ... site security plans. The amendments to 10 CFR 73.55 published on March 27, 2009 (74 FR 13926... on the quality of the human environment (75 FR 69710 dated November 15, 2010). This exemption is... COMMISSION Florida Power Corporation, et al.; Crystal River Unit 3 Nuclear Generating Plant; Exemption...

  15. Commentary: Beyond Stressful Life Events and Depression?--Reflections on Bogdan et al. (2014)

    ERIC Educational Resources Information Center

    Belsky, Jay

    2014-01-01

    In light of continuing disagreement, even at the meta-analytic level, as to whether the gene- × -environment (G×E) interaction involving 5-HTTLPR and stressful life events (SLEs) predicts depression, Bogdan and associates (this issue, Bogdan et al., 2014) sought to extend research on what has become a highly controversial general (GxE) and…

  16. Tensile Behavior of Al2o3/feal + B and Al2o3/fecraly Composites

    NASA Technical Reports Server (NTRS)

    Draper, S. L.; Eldridge, J. I.; Aiken, B. J. M.

    1995-01-01

    The feasibility of Al2O3/FeAl + B and Al2O3/FeCrAlY composites for high-temperature applications was assessed. The major emphasis was on tensile behavior of both the monolithics and composites from 298 to 1100 K. However, the study also included determining the chemical compatibility of the composites, measuring the interfacial shear strengths, and investigating the effect of processing on the strength of the single-crystal Al2O3 fibers. The interfacial shear strengths were low for Al203/FeAl + B and moderate to high for Al203/FeCrAlY. The difference in interfacial bond strengths between the two systems affected the tensile behavior of the composites. The strength of the Al203 fiber was significantly degraded after composite processing for both composite systems and resulted in poor composite tensile properties. The ultimate tensile strength (UTS) values of the composites could generally be predicted with either rule of mixtures (ROM) calculations or existing models when using the strength of the etched-out fiber. The Al2O3/FeAl + B composite system was determined to be unfeasible due to poor interfacial shear strengths and a large mismatch in coefficient of thermal expansion (CTE). Development of the Al2O3/FeCrAlY system would require an effective diffusion barrier to minimize the fiber strength degradation during processing and elevated temperature service.

  17. A New Phase in ALS Research.

    PubMed

    Chong, P Andrew; Forman-Kay, Julie D

    2016-09-01

    In this issue of Structure, Conicella et al. (2016) present evidence that the low complexity C-terminal region of TDP-43 undergoes liquid-liquid phase separation. ALS-associated mutations alter this phase separation process, providing a possible mechanism for the pathology caused by these TDP-43 mutations. The work is strongly supportive of toxic loss of RNA processing function in ALS. PMID:27602988

  18. Memory deficits and retrieval processes in ALS.

    PubMed

    Mantovan, M C; Baggio, L; Dalla Barba, G; Smith, P; Pegoraro, E; Soraru', G; Bonometto, P; Angelini, C

    2003-05-01

    Subtle neuropsychological deficits have been described in patients affected by amyotrophic lateral sclerosis (ALS) without dementia. Overall, selective impairment in memory function has been reported, but the source of memory impairment in ALS has yet to be defined. We performed neuropsychological screening in 20 ALS patients. Semantic encoding and post-encoding cue effects on the retrieval of word lists were investigated in the ALS patients and normal controls. Severity of memory impairment was correlated to cerebral blood perfusion detected by single photon emission computed tomography (SPECT). ALS patients showed moderate impairments in frontal and memory tests. Short-term memory was normal, while serial position retrieval of word lists with normal recency effect but poor primacy effect showed long-term memory deficit. ALS patients performed better in cued encoding than in cued post-encoding recall condition. In the cued post-encoding condition, the primacy effect in word list recall improved significantly in controls, but not in ALS patients, as compared with both the free recall and cued encoding conditions. SPECT hypoperfusion was observed in frontal and temporal areas in ALS patients. ALS patients showed a long-term memory deficit which did not improve in cued post-encoding condition as it does for controls. We hypothesize abnormal retrieval processes related to frontal lobe dysfunction which entails difficulties in generating stable long-memory traces at encoding. PMID:12752394

  19. Interfacial Phenomena in Al/Al, Al/Cu, and Cu/Cu Joints Soldered Using an Al-Zn Alloy with Ag or Cu Additions

    NASA Astrophysics Data System (ADS)

    Pstruś, Janusz; Gancarz, Tomasz

    2014-05-01

    The studies of soldered joints were carried out in systems: Al/solder/Al, Al/solder/Cu, Cu/solder/Cu, where the solder was (Al-Zn)EUT, (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Ag and (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Cu addition. Brazing was performed at 500 °C for 3 min. The EDS analysis indicated that the composition of the layers starting from the Cu pad was CuZn, Cu5Zn8, and CuZn4, respectively. Wetting tests were performed at 500 °C for 3, 8, 15, and 30 min, respectively. Thickness of the layers and their kinetics of growth were measured based on the SEM micrographs. The formation of interlayers was not observed from the side of Al pads. On the contrary, dissolution of the Al substrate and migration of Al-rich particles into the bulk of the solder were observed.

  20. Al-doped ZnO nanocrystals

    NASA Astrophysics Data System (ADS)

    Kadam, Pratibha; Agashe, Chitra; Mahamuni, Shailaja

    2008-11-01

    Al3+-doped ZnO nanocrystals were differently obtained by wet chemical and an electrochemical route. An increase in forbidden gap due to change in crystal size and also due to Al3+ doping in ZnO is critically analyzed. The Moss-Burstein type shift in Al3+-doped ZnO nanocrystals provides an evidence of successful Al3+ doping in ZnO nanocrystals. The possibility of varying the carrier concentration in ZnO nanocrystals is the indirect implication of the present investigations.

  1. Genetics of Familial and Sporadic ALS

    ClinicalTrials.gov

    2016-03-21

    Amyotrophic Lateral Sclerosis (ALS); Familial Amyotrophic Lateral Sclerosis; Amyotrophic Lateral Sclerosis With Frontotemporal Dementia; Lou Gehrig's Disease; Motor Neuron Disease; Primary Lateral Sclerosis

  2. Children and the Outdoor Environment

    ERIC Educational Resources Information Center

    Niklasson, Laila; Sandberg, Anette

    2010-01-01

    In this article we will discuss the outdoor environment for younger children with the help of two different concepts. The first concept, affordance, is well known in the discussion about outdoor environments. What the affordance in the outdoor environment is perceived as can differ between actors. How the affordance is used can be another source…

  3. Mineral Resources and the Environment.

    ERIC Educational Resources Information Center

    National Academy of Sciences, Washington, DC.

    This report presents the findings and recommendations of panels created by the Committee on Mineral Resources and the Environment (COMRATE) to study four topic areas of mineral resources and the environment. The topic areas studied by the panels were: technology, supply, the environment, and demand. Section I, the report of the technology panel,…

  4. Virtual Environments in Biology Teaching

    ERIC Educational Resources Information Center

    Mikropoulos, Tassos A.; Katsikis, Apostolos; Nikolou, Eugenia; Tsakalis, Panayiotis

    2003-01-01

    This article reports on the design, development and evaluation of an educational virtual environment for biology teaching. In particular it proposes a highly interactive three-dimensional synthetic environment involving certain learning tasks for the support of teaching plant cell biology and the process of photosynthesis. The environment has been…

  5. Java-based communication in a High Performance Computing environment

    NASA Astrophysics Data System (ADS)

    Fries, A.; de Mora, J. Portell I.; Sirvent, R.

    2011-02-01

    Java is one of the most widely used computer programming languages, however its use in High Performance Computing (HPC) is relatively low. A typical HPC environment consists of a number of multi-core computing nodes, while a typical application running in such an environment will normally contain CPU intensive code that can be executed in parallel. Such an application may require inter-node as well as intra-node communication. Message Passing Interface (MPI) is a language independent specification of an API to allow such communication. MPJExpress (Baker et al. 2006) and F-MPJ (Taboada et al. 2009) are Java-based implementations of MPI, designed with the efficient performance of data transfers as a main objective. In this paper we discuss the scalability of one approach of distributing data to compute nodes in HPC and we propose the design of an alternative data transfer system, building upon MPI.

  6. Theoretical studies of a new double graded band-gap Al sub x Ga sub 1-x As-Al sub y Ga sub 1-y As

    NASA Technical Reports Server (NTRS)

    Hutchby, J. A.

    1977-01-01

    A new double graded band-gap (DGBG) Al sub x Ga sub l-x As-Al sub z Ga sub l-z As solar cell has potential for providing high efficiency performance throughout the entire life of a solar cell in a space environment. A preliminary theoretical analysis indicates that short circuit current available from an optimized DGBG cell is slightly larger than that of a previously reported single graded band-gap cell. However, the DGBG cell potentially offers a substantial improvement in radiation resistance of the base region.

  7. Stress corrosion cracking of Ti-8Al-1 Mo-1V in molten salts

    NASA Technical Reports Server (NTRS)

    Smyrl, W. H.; Blackburn, M. J.

    1975-01-01

    The stress corrosion cracking (SCC) behavior of Ti-8Al-1 Mo-1V has been studied in several molten salt environments. Extensive data are reported for the alloy in highly pure LiCl-KCl. The influence of the metallurgical heat treatment and texture, and the mechanical microstructure show similarities with aqueous solutions at lower temperature. The fracture path and cracking modes are also similar to that found in other environments. The influence of H2O and H(-) in molten LiCl-KCl lead to the conclusion that hydrogen does not play a major role in crack extension in this environment.

  8. Effect of adsorbed and substituted Al on Fe(II)-induced mineralization pathways of ferrihydrite

    NASA Astrophysics Data System (ADS)

    Hansel, C. M.; Learman, D. R.; Lentini, C. J.; Ekstrom, E. B.

    2011-08-01

    The poorly crystalline Fe(III) hydroxide ferrihydrite is considered one of the most important sinks for (in)organic contaminants and nutrients within soils, sediments, and waters. The ripening of ferrihydrite to more stable and hence less reactive phases such as goethite is catalyzed by surface reaction with aqueous Fe(II). While ferrihydrite within most natural environments contains high concentrations of adsorbed or co-precipitated cations (particularly Al), little is known regarding the impact of these cations on Fe(II)-induced transformation of ferrihydrite to secondary phases. Accordingly, we explored the extent, rates, and pathways of Fe(II)-induced secondary mineralization of Al-ferrihydrites by reacting aqueous Fe(II) (0.2 and 2.0 mM) with 2-line ferrihydrite containing a range of Al levels substituted within (6-24 mol% Al) or adsorbed on the surface (0.1-27% Γmax). Here, we show that regardless of the Fe(II) concentration, Al substituted within or adsorbed on ferrihydrite results in diminished secondary mineralization and preservation of ferrihydrite. In contrast to pure ferrihydrite, the concentration of Fe(II) may not in fact influence the mineralization products of Al-compromised ferrihydrites. Furthermore, the secondary mineral profiles upon Fe(II) reaction with ferrihydrite are not only a function of Al concentration but also the mode of Al incorporation. While Al substitution impedes lepidocrocite formation and magnetite nucleation, Al adsorption completely inhibits goethite formation and appears to have a lesser impact on magnetite nucleation. When normalized to total Al content associated with ferrihydrite, Al adsorption results in greater degree of ferrihydrite preservation relative to Al substitution. These findings provide insight into mechanisms that may be responsible for ferrihydrite preservation and low levels of secondary magnetite typically found in sedimentary environments. Considering the preponderance of cation substitution within and

  9. Processing and Mechanical Properties of Directionally Solidified NiAl/NiAlTa Alloys

    NASA Technical Reports Server (NTRS)

    Johnson, D. R.; Oliver, B. F.; Noebe, R. D.; Whittenberger, J. D.

    1994-01-01

    Promising creep strengths were found for a directionally solidified NiAl-NiAlTa alloy when compared to other NiAl based intermetallics. The directionally solidified alloy had an off-eutectic composition that resulted in microstructures consisting of NiAl dendrites surrounded by aligned eutectic regions. The room temperature toughness of the two phase alloy was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa. Alloying additions that may improve the room temperature toughness by producing multiphase alloys are discussed.

  10. Effects of the Al content on pore structures of porous TieAl alloys

    SciTech Connect

    Jiang, Y; He, Y H; Zou, J; Huang, B; Liu, C

    2008-01-01

    PorousTi Alalloys with different nominal compositions were fabricated through a reactive synthesis of Ti and Al elemental powders. It has been found that the pore parameters vary with the Al contents, indicating that the nature of the pores can be manipulated through changing the Al contents. In addition, detailed structural characterizations showed that the fabricated porousTi Alalloys can have three crystalline phases (i.e., 2-Ti3Al, -TiAl, and TiAl3) when using different compositions. The fundamental reasons behind these phenomena have been explored.

  11. Salinization and Saline Environments

    NASA Astrophysics Data System (ADS)

    Vengosh, A.

    2003-12-01

    One of the most conspicuous phenomena of water-quality degradation, particularly in arid and semi-arid zones, is salinization of water and soil resources. Salinization is a long-term phenomenon, and during the last century many aquifers and river basins have become unsuitable for human consumption owing to high levels of salinity. Future exploitation of thousands of wells in the Middle East and in many other water-scarce regions in the world depends, to a large extent, on the degree and rate of salinization. Moreover, every year a large fraction of agricultural land is salinized and becomes unusable.Salinization is a global environmental phenomenon that affects many different aspects of our life (Williams, 2001a, b): changing the chemical composition of natural water resources (lakes, rivers, and groundwater), degrading the quality of water supply to the domestic and agriculture sectors, contribution to loss of biodiversity, taxonomic replacement by halotolerant species ( Williams, 2001a, b), loss of fertile soil, collapse of agricultural and fishery industries, changing of local climatic conditions, and creating severe health problems (e.g., the Aral Basin). The damage due to salinity in the Colorado River Basin alone, for example, ranges between 500 and 750 million per year and could exceed 1 billion per year if the salinity in the Imperial Dam increases from 700 mg L-1 to 900 mg L-1 (Bureau of Reclamation, 2003, USA). In Australia, accelerating soil salinization has become a massive environmental and economic disaster. Western Australia is "losing an area equal to one football oval an hour" due to spreading salinity ( Murphy, 1999). The annual cost for dryland salinity in Australia is estimated as AU700 million for lost land and AU$130 million for lost production ( Williams et al., 2002). In short, the salinization process has become pervasive.Salinity in water is usually defined by the chloride content (mg L-1) or total dissolved solids content (TDS, mg L-1or g

  12. Ancient aqueous environments at Endeavour crater, Mars

    USGS Publications Warehouse

    Arvidson, R. E.; Squyres, S. W.; Bell, J.F., III; Catalano, J.G.; Clark, B. C.; Crumpler, L.S.; de Souza, P.A., Jr.; Fairén, A.G.; Farrand, W. H.; Fox, V.K.; Gellert, Ralf; Ghosh, A.; Golombeck, M.P.; Grotzinger, J.P.; Guinness, E.A.; Herkenhoff, Kenneth E.; Jolliff, B.L.; Knoll, A.H.; Li, R.; McLennan, S.M.; Ming, D. W.; Mittlefehldt, D. W.; Moore, Johnnie N.; Morris, R.V.; Murchie, S.L.; Parker, T.J.; Paulsen, G.; Rice, J.W.; Ruff, S.W.; Smith, M.D.; Wolff, M.J.

    2014-01-01

    Opportunity has investigated in detail rocks on the rim of the Noachian age Endeavour crater, where orbital spectral reflectance signatures indicate the presence of Fe+3-rich smectites. The signatures are associated with fine-grained, layered rocks containing spherules of diagenetic or impact origin. The layered rocks are overlain by breccias, and both units are cut by calcium sulfate veins precipitated from fluids that circulated after the Endeavour impact. Compositional data for fractures in the layered rocks suggest formation of Al-rich smectites by aqueous leaching. Evidence is thus preserved for water-rock interactions before and after the impact, with aqueous environments of slightly acidic to circum-neutral pH that would have been more favorable for prebiotic chemistry and microorganisms than those recorded by younger sulfate-rich rocks at Meridiani Planum.

  13. Ancient aqueous environments at Endeavour crater, Mars.

    PubMed

    Arvidson, R E; Squyres, S W; Bell, J F; Catalano, J G; Clark, B C; Crumpler, L S; de Souza, P A; Fairén, A G; Farrand, W H; Fox, V K; Gellert, R; Ghosh, A; Golombek, M P; Grotzinger, J P; Guinness, E A; Herkenhoff, K E; Jolliff, B L; Knoll, A H; Li, R; McLennan, S M; Ming, D W; Mittlefehldt, D W; Moore, J M; Morris, R V; Murchie, S L; Parker, T J; Paulsen, G; Rice, J W; Ruff, S W; Smith, M D; Wolff, M J

    2014-01-24

    Opportunity has investigated in detail rocks on the rim of the Noachian age Endeavour crater, where orbital spectral reflectance signatures indicate the presence of Fe(+3)-rich smectites. The signatures are associated with fine-grained, layered rocks containing spherules of diagenetic or impact origin. The layered rocks are overlain by breccias, and both units are cut by calcium sulfate veins precipitated from fluids that circulated after the Endeavour impact. Compositional data for fractures in the layered rocks suggest formation of Al-rich smectites by aqueous leaching. Evidence is thus preserved for water-rock interactions before and after the impact, with aqueous environments of slightly acidic to circum-neutral pH that would have been more favorable for prebiotic chemistry and microorganisms than those recorded by younger sulfate-rich rocks at Meridiani Planum. PMID:24458648

  14. The origin of external oxygen in Jupiter and Saturn's environments

    NASA Astrophysics Data System (ADS)

    Cavalié, T.; Lellouch, E.; Hartogh, P.; Moreno, R.; Billebaud, F.; Bockelée-Morvan, D.; Biver, N.; Cassidy, T.; Courtin, R.; Crovisier, J.; Dobrijevic, M.; Feuchtgruber, H.; González, A.; Greathouse, T.; Jarchow, C.; Kidger, M.; Lara, L. M.; Rengel, M.; Orton, G.; Sagawa, H.; de Val-Borro, M.

    2014-12-01

    This paper reviews the recent findings of the Herschel Solar System Observations Key Program (Hartogh et al. 2009), as well as ground-based supporting observations, regarding the origin of external oxygen in the environments of Jupiter and Saturn. Herschel-HIFI and PACS observations have been used to shown that the Shoemaker-Levy 9 comet is the source of Jupiter's stratospheric water, and that Enceladus (and its geysers) are most probably the source of water for Saturn and Titan.

  15. Response to Signorovitch et al.

    PubMed

    Flot, Jean-François; Debortoli, Nicolas; Hallet, Bernard; Van Doninck, Karine

    2016-08-22

    Signorovitch et al.[1] comment that an Oenothera-like meiosis [2] could produce a pattern similar to what we observed in our study of natural isolates of the bdelloid rotifer Adineta vaga, which we attributed to horizontal gene transfers (HGTs) [3]. Indeed, our HGT hypothesis appears at first sight difficult to conciliate with their observation of a congruent pattern of allele sharing at four large loci possibly located on different chromosomes [4]. However, one might imagine conditions under which massive horizontal gene transfer between bdelloid individuals could produce such a pattern, notably if the individuals involved had previously lost most of their heterozygosity because of their exposure to frequent desiccation (which produces DNA double-strand breaks [5]). In the published A. vaga genome the loss of heterozygosity due to large-scale gene conversion events or break-induced replication covers only about 10% of the genome [6], but this percentage may be much higher in environmental isolates that often experience dessication. Besides, if an Oenothera-like mode of meiosis occurs in bdelloids frequently enough to be detected in a single sampling of 29 individuals (as in [4]), one would expect males and meiosis to be observed at least occasionally, and instances of congruent allele sharing across loci should turn up frequently in genetic surveys. This was not the case in [3]: among the 82 A. vaga individuals sequenced for four nuclear markers, no trio of individuals presented congruent patterns of shared sequences at different loci. For these reasons, and in the absence of any direct evidence for an Oenothera-like meiosis in bdelloids, we still consider inter-bdelloid HGTs a more parsimonious explanation for our results. PMID:27554651

  16. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions

    NASA Astrophysics Data System (ADS)

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-07-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits.

  17. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions

    PubMed Central

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-01-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits. PMID:27403611

  18. Atomic structure and oxygen deficiency of the ultrathin aluminium oxide barrier in Al/AlOx/Al Josephson junctions.

    PubMed

    Zeng, Lunjie; Tran, Dung Trung; Tai, Cheuk-Wai; Svensson, Gunnar; Olsson, Eva

    2016-01-01

    Al/AlOx/Al Josephson junctions are the building blocks of a wide range of superconducting quantum devices that are key elements for quantum computers, extremely sensitive magnetometers and radiation detectors. The properties of the junctions and the superconducting quantum devices are determined by the atomic structure of the tunnel barrier. The nanoscale dimension and disordered nature of the barrier oxide have been challenges for the direct experimental investigation of the atomic structure of the tunnel barrier. Here we show that the miniaturized dimension of the barrier and the interfacial interaction between crystalline Al and amorphous AlOx give rise to oxygen deficiency at the metal/oxide interfaces. In the interior of the barrier, the oxide resembles the atomic structure of bulk aluminium oxide. Atomic defects such as oxygen vacancies at the interfaces can be the origin of the two-level systems and contribute to decoherence and noise in superconducting quantum circuits. PMID:27403611

  19. Visual Environments for CFD Research

    NASA Technical Reports Server (NTRS)

    Watson, Val; George, Michael W. (Technical Monitor)

    1994-01-01

    This viewgraph presentation gives an overview of the visual environments for computational fluid dynamics (CFD) research. It includes details on critical needs from the future computer environment, features needed to attain this environment, prospects for changes in and the impact of the visualization revolution on the human-computer interface, human processing capabilities, limits of personal environment and the extension of that environment with computers. Information is given on the need for more 'visual' thinking (including instances of visual thinking), an evaluation of the alternate approaches for and levels of interactive computer graphics, a visual analysis of computational fluid dynamics, and an analysis of visualization software.

  20. [Environment and rural development].

    PubMed

    Dufumier, M

    1992-01-01

    Management of natural resources and preservation of ecological balance are perceived today as essential elements of rural development. The recently multiplying environmental ministries in developing countries are intended not only to correct the damages resulting from uncontrolled urbanization and industrialization, but to address ecosystemic degradation in the countryside. The aptitude demonstrated by numerous peasant societies for exploiting their environments over the long term while preserving their potential should be recognized and their specific, detailed knowledge incorporated into environmental protection projects. It is a mistake to conclude that peasants do not care about environmental problems; they often lack the resources to take needed action. Active participation of impoverished rural dwellers requires that measures taken do not reduce their incomes or resources in the short term. Rural development projects must assure protection of the environment while taking into account the interests of diverse categories of rural dwellers, such as farmers, herders, or wood cutters. There has been considerable progress in the past 2 decades in understanding the functioning of cultivated and pasture ecosystems and in developing techniques to limit damage to them. A vast effort is now needed to understand the economic, social, and cultural functions of customs and practices of different social groups involved in agricultural development and territorial management in order to prioritize problems and arrive at a consensus of all those affected concerning environmental protection. Social science research is needed into marketing of agricultural products, circulation of cooking fuels, village-town relations, and migration in order to determine the effects of these phenomena on management and conservation of natural resources in rural areas. Experimental research should be directed toward finding practical solutions to problems encountered by rural cultivators