WorldWideScience

Sample records for jwst fine phasing

  1. Phase and Pupil Amplitude Recovery for JWST Space-Optics Control

    Science.gov (United States)

    Dean, B. H.; Zielinski, T. P.; Smith, J. S.; Bolcar, M. R.; Aronstein, D. L.; Fienup, J. R.

    2010-01-01

    This slide presentation reviews the phase and pupil amplitude recovery for the James Webb Space Telescope (JWST) Near Infrared Camera (NIRCam). It includes views of the Integrated Science Instrument Module (ISIM), the NIRCam, examples of Phase Retrieval Data, Ghost Irradiance, Pupil Amplitude Estimation, Amplitude Retrieval, Initial Plate Scale Estimation using the Modulation Transfer Function (MTF), Pupil Amplitude Estimation vs lambda, Pupil Amplitude Estimation vs. number of Images, Pupil Amplitude Estimation vs Rotation (clocking), and Typical Phase Retrieval Results Also included is information about the phase retrieval approach, Non-Linear Optimization (NLO) Optimized Diversity Functions, and Least Square Error vs. Starting Pupil Amplitude.

  2. Phase-Retrieval Uncertainty Estimation and Algorithm Comparison for the JWST-ISIM Test Campaign

    Science.gov (United States)

    Aronstein, David L.; Smith, J. Scott

    2016-01-01

    Phase retrieval, the process of determining the exitpupil wavefront of an optical instrument from image-plane intensity measurements, is the baseline methodology for characterizing the wavefront for the suite of science instruments (SIs) in the Integrated Science Instrument Module (ISIM) for the James Webb Space Telescope (JWST). JWST is a large, infrared space telescope with a 6.5-meter diameter primary mirror. JWST is currently NASA's flagship mission and will be the premier space observatory of the next decade. ISIM contains four optical benches with nine unique instruments, including redundancies. ISIM was characterized at the Goddard Space Flight Center (GSFC) in Greenbelt, MD in a series of cryogenic vacuum tests using a telescope simulator. During these tests, phase-retrieval algorithms were used to characterize the instruments. The objective of this paper is to describe the Monte-Carlo simulations that were used to establish uncertainties (i.e., error bars) for the wavefronts of the various instruments in ISIM. Multiple retrieval algorithms were used in the analysis of ISIM phase-retrieval focus-sweep data, including an iterativetransform algorithm and a nonlinear optimization algorithm. These algorithms emphasize the recovery of numerous optical parameters, including low-order wavefront composition described by Zernike polynomial terms and high-order wavefront described by a point-by-point map, location of instrument best focus, focal ratio, exit-pupil amplitude, the morphology of any extended object, and optical jitter. The secondary objective of this paper is to report on the relative accuracies of these algorithms for the ISIM instrument tests, and a comparison of their computational complexity and their performance on central and graphical processing unit clusters. From a phase-retrieval perspective, the ISIM test campaign includes a variety of source illumination bandwidths, various image-plane sampling criteria above and below the Nyquist- Shannon

  3. Non-redundant Aperture Masking Interferometry (AMI) and segment phasing with JWST-NIRISS

    Science.gov (United States)

    Sivaramakrishnan, Anand; Lafrenière, David; Ford, K. E. Saavik; McKernan, Barry; Cheetham, Anthony; Greenbaum, Alexandra Z.; Tuthill, Peter G.; Lloyd, James P.; Ireland, Michael J.; Doyon, René; Beaulieu, Mathilde; Martel, André; Koekemoer, Anton; Martinache, Frantz; Teuben, Peter

    2012-09-01

    The Aperture Masked Interferometry (AMI) mode on JWST-NIRISS is implemented as a 7-hole, 15% throughput, non-redundant mask (NRM) that operates with 5-8% bandwidth filters at 3.8, 4.3, and 4.8 microns. We present refined estimates of AMI's expected point-source contrast, using realizations of noise matched to JWST pointing requirements, NIRISS detector noise, and Rev-V JWST wavefront error models for the telescope and instrument. We describe our point-source binary data reduction algorithm, which we use as a standardized method to compare different observational strategies. For a 7.5 magnitude star we report a 10-a detection at between 8.7 and 9.2 magnitudes of contrast between 100 mas to 400 mas respectively, using closure phases and squared visibilities in the absence of bad pixels, but with various other noise sources. With 3% of the pixels unusable, the expected contrast drops by about 0.5 magnitudes. AMI should be able to reach targets as bright as M=5. There will be significant overlap between Gemini-GPI and ESO-SPHERE targets and AMI's search space, and a complementarity with NIRCam's coronagraph. We also illustrate synthesis imaging with AMI, demonstrating an imaging dynamic range of 25 at 100 mas scales. We tailor existing radio interferometric methods to retrieve a faint bar across a bright nucleus, and explain the similarities to synthesis imaging at radio wavelengths. Modest contrast observations of dusty accretion flows around AGNs will be feasible for NIRISS AMI. We show our early results of image-plane deconvolution as well. Finally, we report progress on an NRM-inspired approach to mitigate mission-level risk associated with JWST's specialized wavefront sensing hardware. By combining narrow band and medium band Nyquist-sampled images taken with a science camera we can sense JWST primary mirror segment tip-tilt to lOmas, and piston to a few nm. We can sense inter-segment piston errors of up to 5 coherence lengths of the broadest bandpass filter used

  4. In-focus phase retrieval using JWST-NIRISS's non-redundant mask

    Science.gov (United States)

    Greenbaum, Alexandra Z.; Gamper, Noah; Sivaramakrishnan, Anand

    2016-07-01

    The James Webb Space Telescope's Near InfraRed Imager and Slitless Spectrograph (NIRISS) contains a 7-hole non-redundant mask (NRM) in its pupil. NIRISS's Aperture Masking Interferometry (AMI) mode is useful both for science as well as wavefront sensing. In-focus science detector NRM and full pupil images of unresolved stars can be used to measure the wavefront without any dedicated wavefront sensing hardware or any moving mirrors. Using routine science operational sequences, these images can be taken before or after any science visit. NRM fringe phases constrain Gerchberg-Saxton phase retrieval to disambiguate the algorithm's two-fold degeneracy. We summarize how consecutive masked and unmasked exposures provide enough information to reconstruct a wavefront with up to ˜1-2 rms radians of error. We present our latest progress on using this approach on laboratory experiments, and discuss those results in the context of contingency for JWST segment phasing. We discuss extending our method to ground-based AO systems and future space telescopes.

  5. Calibration results using highly aberrated images for aligning the JWST instruments to the telescope

    Science.gov (United States)

    Smith, Koby Z.; Acton, D. Scott; Gallagher, Ben B.; Knight, J. Scott; Dean, Bruce H.; Jurling, Alden S.; Zielinski, Thomas P.

    2016-07-01

    The James Webb Space Telescope (JWST) project is an international collaboration led by NASA's Goddard Space Flight Center (GSFC) in Greenbelt, MD. JWST is NASA's flagship observatory that will operate nearly a million miles away from Earth at the L2 Lagrange point. JWST's optical design is a three-mirror anastigmat with four main optical components; 1) the eighteen Primary Mirror Segment Assemblies (PMSA), 2) a single Secondary Mirror Assembly (SMA), 3) an Aft-Optics Subsystem (AOS) consisting of a Tertiary Mirror and Fine Steering Mirror, and 4) an Integrated Science Instrument Module consisting of the various instruments for JWST. JWST's optical system has been designed to accommodate a significant amount of alignment capability and risk with the PMSAs and SMA having rigid body motion available on-orbit just for alignment purposes. However, the Aft-Optics Subsystem (AOS) and Integrated Science Instrument Module (ISIM) are essentially fixed optical subsystems within JWST, and therefore the cryogenic alignment of the AOS to the ISIM is critical to the optical performance and mission success of JWST. In support of this cryogenic alignment of the AOS to ISIM, an array of fiber optic sources, known as the AOS Source Plate Assembly (ASPA), are placed near the intermediate image location of JWST (between the secondary and tertiary mirrors) during thermal vacuum ground-test operations. The AOS produces images of the ASPA fiber optic sources at the JWST focal surface location, where they are captured by the various science instruments. In this manner, the AOS provides an optical yardstick by which the instruments within ISIM can evaluate their relative positions to and the alignment of the AOS to ISIM can be quantified. However, since the ASPA is located at the intermediate image location of the JWST three-mirror anastigmat design, the images of these fiber optic sources produced by the AOS are highly aberrated with approximately 2-3μm RMS wavefront error consisting

  6. Lenses for JWST

    Science.gov (United States)

    Ebeling, Harald; Richard, Johan; Kneib, Jean-Paul; Repp, Andrew; Atek, Hakim; Egami, Eiichi; Windhorst, Rogier; Edge, Alastair

    2016-08-01

    JWST will dramatically advance our knowledge and understanding of the first generations of galaxies at z>10, their role in the re-ionization of the Universe, and the evolutionary processes that gave rise to the complexity and diversity of galaxies at the current epoch. As demonstrated by HST legacy projects like CLASH and the Hubble Frontier Fields, gravitational amplification by massive galaxy clusters can significantly extend the depth of the required observations. However, for JWST, reducing any diffuse background light will be just as crucial. We here propose Spitzer/IRAC observations of six massive cluster lenses, specifically selected as candidates for observation with JWST. By (a) quantifying the amount of intra-cluster light and (b) enabling us to improve our current lens models, the data resulting from the requested observations will be instrumental for the final selection of cluster targets that maximize the scientific returns of deep JWST observations.

  7. Cryogenic Thermal Distortion Model Validation for the JWST ISIM Structure

    Science.gov (United States)

    Johnston, John; Cofie, Emmanuel

    2011-01-01

    The James Webb Space Telescope (JWST) is a large, infrared-optimized space telescope consisting of an Optical telescope element (OTE), Integrated science instrument module (ISIM), a Spacecraft, and a Sunshield. The Integrated Science Instrument Module (ISIM) consists of the JWST science instruments (NIRCam, MIRI, NIRSpec), a fine guidance sensor (FGS), the ISIM Structure, and thermal and electrical subsystems. JWST's instruments are designed to work primarily in the infrared range of the electromagnetic spectrum, and the instruments and telescope operate at cryogenic temperatures (approximately 35 K for the instruments).

  8. Transiting Exoplanets with JWST

    CERN Document Server

    Seager, S; Valenti, J A

    2008-01-01

    The era of exoplanet characterization is upon us. For a subset of exoplanets -- the transiting planets -- physical properties can be measured, including mass, radius, and atmosphere characteristics. Indeed, measuring the atmospheres of a further subset of transiting planets, the hot Jupiters, is now routine with the Spitzer Space Telescope. The James Webb Space Telescope (JWST) will continue Spitzer's legacy with its large mirror size and precise thermal stability. JWST is poised for the significant achievement of identifying habitable planets around bright M through G stars--rocky planets lacking extensive gas envelopes, with water vapor and signs of chemical disequilibrium in their atmospheres. Favorable transiting planet systems, are, however, anticipated to be rare and their atmosphere observations will require tens to hundreds of hours of JWST time per planet. We review what is known about the physical characteristics of transiting planets, summarize lessons learned from Spitzer high-contrast exoplanet m...

  9. Status of the JWST Science Instrument Payload

    Science.gov (United States)

    Greenhouse, Matt

    2016-01-01

    The James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) system consists of five sensors (4 science): Mid-Infrared Instrument (MIRI), Near Infrared Imager and Slitless Spectrograph (NIRISS), Fine Guidance Sensor (FGS), Near InfraRed Camera (NIRCam), Near InfraRed Spectrograph (NIRSpec); and nine instrument support systems: Optical metering structure system, Electrical Harness System; Harness Radiator System, ISIM Electronics Compartment, ISIM Remote Services Unit, Cryogenic Thermal Control System, Command and Data Handling System, Flight Software System, Operations Scripts System.

  10. JWST Pathfinder Telescope Integration

    Science.gov (United States)

    Matthews, Gary W.; Kennard, Scott H.; Broccolo, Ronald T.; Ellis, James M.; Daly, Elizabeth A.; Hahn, Walter G.; Amon, John N.; Mt. Pleasant, Stephen M.; Texter, Scott; Atkinson, Charles B.; McKay, Andrew; Levi, Joshua; Keski-Kuha, Ritva; Feinberg, Lee

    2015-01-01

    The James Webb Space Telescope (JWST) is a 6.5m, segmented, IR telescope that will explore the first light of the universe after the big bang. In 2014, a major risk reduction effort related to the Alignment, Integration, and Test (AI&T) of the segmented telescope was completed. The Pathfinder telescope includes two Primary Mirror Segment Assemblies (PMSA's) and the Secondary Mirror Assembly (SMA) onto a flight-like composite telescope backplane. This pathfinder allowed the JWST team to assess the alignment process and to better understand the various error sources that need to be accommodated in the flight build. The successful completion of the Pathfinder Telescope provides a final integration roadmap for the flight operations that will start in August 2015.

  11. Laser phase-detector and counter for fine displacement measurement

    Science.gov (United States)

    Row, R. T.; Wang, C. P.

    A simple technique for the measurement of fine displacement has been developed. With use of an HeNe laser, an optical phase-detector, and counter, a displacement accuracy of 300 nm has been demonstrated over a range of 2 cm.

  12. Solar System Observations with JWST

    Science.gov (United States)

    Norwood, James; Hammel, Heidi; Milam, Stefanie; Stansberry, John; Lunine, Jonathan; Chanover, Nancy; Hines, Dean; Sonneborn, George; Tiscareno, Matthew; Brown, Michael; Ferruit, Pierre

    2014-01-01

    The James Webb Space Telescope will enable a wealth of new scientific investigations in the near- and mid- infrared, with sensitivity and spatial-spectral resolution greatly surpassing its predecessors. In this paper, we focus upon Solar System science facilitated by JWST, discussing the most current information available concerning JWST instrument properties and observing techniques relevant to planetary science. We also present numerous example observing scenarios for a wide variety of Solar System targets to illustrate the potential of JWST science to the Solar System community. This paper updates and supersedes the Solar System white paper published by the JWST Project in 2010 (Lunine et al., 2010). It is based both on that paper and on a workshop held at the annual meeting of the Division for Planetary Sciences in Reno, NV in 2012.

  13. Magnetic phases in lunar fines - Metallic Fe or ferric oxides.

    Science.gov (United States)

    Tsay, F.-D.; Manatt, S. L.; Chan, S. I.

    1973-01-01

    The ferromagnetic resonance observed for the Apollo 11 and 12 lunar fines is characterized by an asymmetric lineshape with a narrower appearance on the high field side. This asymmetry together with an anisotropy energy which varies from +640 to +500 G over the temperature range of 80 to 298 K indicate that the ferromagnetic resonance arises from metallic Fe having the body-centered cubic structure and not from hematite, magnetite or other Fe(3+) ions in magnetite-like phases. The g-value, the lineshape asymmetry, and the temperature dependence of the linewidth for the Apollo 14 and 15 fines as reported by other workers are found to be essentially similar to those observed for the Apollo 11 and 12 fines.

  14. Ultra-Fine Grained Dual-Phase Steels

    Directory of Open Access Journals (Sweden)

    Matthias Militzer

    2012-10-01

    Full Text Available This paper provides an overview on obtaining low-carbon ultra-fine grained dual-phase steels through rapid intercritical annealing of cold-rolled sheet as improved materials for automotive applications. A laboratory processing route was designed that involves cold-rolling of a tempered martensite structure followed by a second tempering step to produce a fine grained aggregate of ferrite and carbides as the initial microstructure for rapid intercritical annealing. The intercritical annealing step was performed with heating and cooling rates of at least 100 °C/s and a holding time of 30 s. The intercritical temperature was selected to result in 20- 35% martensite in the final microstructures for C-Mn steels with carbon contents of 0.06, 0.12 and 0.17 wt%, respectively. The proposed processing routes produced an ultra-fine grained ferrite-martensite structure withgrain sizes of approximately 1 ?m for all three steels. The tensile strength of these ultra-fine grained dualphase steels can be increased by up to 200 MPa as compared to coarse-grained dual-phase steels while maintaining uniform elongation values. The rather narrow processing window necessary to obtain these properties was evaluated by determining the effect of intercritical annealing conditions on microstructure evolution. Further, the experimental results were confirmed with phase field simulations of austenite formation indicating that rapid heat treatment cycles are essential to obtain fine grained intercritical austenite that leads to martensite islands with sizes of 1 ?m and below in the final microstructure.

  15. Diffused phase transition in fine-grained bismuth vanadate ceramics

    OpenAIRE

    Shantha, K; Varma, KBR

    1999-01-01

    Nanocrystalline powders of ferroelectric bismuth vanadate, Bi4V2O11 (n-BiV), with crystallite size less than 50 nm, were obtained by mechanical milling of a stoichiometric mixture of bismuth oxide and vanadium pentoxide. The n-BiV powders on sintering yielded high-density, fine-grained ceramics with improved dielectric and polar characteristics. Dielectric studies on samples obtained from milled powders indicated that the ferroelectric-to-paraelectric phase transition temperature is strongly ...

  16. Observing Dark Stars with JWST

    CERN Document Server

    Ilie, Cosmin; Valluri, Monica; Iliev, Ilian T; Shapiro, Paul

    2011-01-01

    We study the capability of the James Webb Space Telescope (JWST) to detect Supermassive Dark Stars (SMDS). If the first stars are powered by dark matter heating in triaxial dark matter haloes, they may grow to be very large and very bright, visible in deep imaging with JWST and even Hubble Space Telescope (HST). We use HST surveys to place bounds on the numbers of SMDSs that may be detected in future JWST imaging surveys. We showed that SMDS in the mass range $10^6-10^7 M_\\odot$ are bright enough to be detected in all the wavelength bands of the NIRCam on JWST . If SMDSs exist at z ~10, 12, and 14, they will be detectable as J-band, H-band, or K-band dropouts, respectively. With a total survey area of 150 arcmin^2 (assuming a multi-year deep parallel survey with JWST), we find that typically the number of $10^6 M_\\odot$ SMDSs found as H or K-band dropouts is ~10^5\\fsmds, where the fraction of early DM haloes hosting DS is likely to be small, \\fsmds10 from SMDSs would be possible with spectroscopy: the SMDS (w...

  17. Performance of the primary mirror center-of-curvature optical metrology system during cryogenic testing of the JWST Pathfinder telescope

    Science.gov (United States)

    Hadaway, James B.; Wells, Conrad; Olczak, Gene; Waldman, Mark; Whitman, Tony; Cosentino, Joseph; Connolly, Mark; Chaney, David; Telfer, Randal

    2016-07-01

    The James Webb Space Telescope (JWST) primary mirror (PM) is 6.6 m in diameter and consists of 18 hexagonal segments, each 1.5 m point-to-point. Each segment has a six degree-of-freedom hexapod actuation system and a radius of-curvature (RoC) actuation system. The full telescope will be tested at its cryogenic operating temperature at Johnson Space Center. This testing will include center-of-curvature measurements of the PM, using the Center-of-Curvature Optical Assembly (COCOA) and the Absolute Distance Meter Assembly (ADMA). The COCOA includes an interferometer, a reflective null, an interferometer-null calibration system, coarse and fine alignment systems, and two displacement measuring interferometer systems. A multiple-wavelength interferometer (MWIF) is used for alignment and phasing of the PM segments. The ADMA is used to measure, and set, the spacing between the PM and the focus of the COCOA null (i.e. the PM center-of-curvature) for determination of the ROC. The performance of these metrology systems was assessed during two cryogenic tests at JSC. This testing was performed using the JWST Pathfinder telescope, consisting mostly of engineering development and spare hardware. The Pathfinder PM consists of two spare segments. These tests provided the opportunity to assess how well the center-of-curvature optical metrology hardware, along with the software and procedures, performed using real JWST telescope hardware. This paper will describe the test setup, the testing performed, and the resulting metrology system performance. The knowledge gained and the lessons learned during this testing will be of great benefit to the accurate and efficient cryogenic testing of the JWST flight telescope.

  18. NEOs in the mid-infrared: from Spitzer to JWST

    Science.gov (United States)

    Mueller, Michael; Thomas, Cristina A.

    2016-10-01

    Near-Earth Objects (NEOs) account for a surprisingly large fraction of the Spitzer observing time devoted to Solar System science. As a community, we should think of ways to repeat that success with JWST. JWST is planning an open Early Release Science Program, with the expected deadline for letters of intent in early 2017. We can't wait for next year's DPS to develop ideas. The time is now!In order to stir up the discussion, we will present ideas for NEO observing programs that are well adapted to JWST's capabilities and limitations, based on our recent PASP paper (Thomas et al., 2016). Obvious measurement objectives would include* size and albedo from thermal continuum (MIRI photometry)* thermal inertia for objects with well-known shape and spin state (MIRI)* taxonomy through reflection spectroscopy and emission spectroscopy in the NIR and MIR; NIR colors for faint objects.In all cases, JWST's sensitivity will allow us to go deeper than currently possible by at least an order of magnitude. Meter-sized NEOs similar to 2009 BD or 2011 MD are easy targets for MIRI spectrophotometry!The following limitations must be kept in mind, however: JWST's large size makes it slow to move. Most problematic for NEOs is probably the resulting 'speed limit': non-sidereal tracking is supported up to a rate of 30 mas/s, NEOs can easily move faster than that (ways to relax this constraint are under discussion). The average slew to a new target is budgeted to take 30 min, effectively ruling out programs many-target programs like ExploreNEOs or NEOSurvey (see D. Trilling's paper). Additionally, JWST will only observe close to quadrature, translating to large solar phase angles for NEO observations; this is familiar from other space-based IR facilities.

  19. Fine water spray for fire extinguishing. Phase 2: Turbine hood

    Science.gov (United States)

    Aune, P.; Wighus, R.; Drangsholt, G.; Stensaas, J. P.

    1994-12-01

    SINTEF has carried out tests of a Fine Water Spray fire suppression system intended to be used as a replacement for Halon systems in turbine hoods on offshore platforms operated by British Petroleum Norway. The tests were carried out in a 70 cu m full scale model representing a turbine hood of the Ula platform in the North Sea. A mock-up of a gas turbine was installed in the model. The scope of work in Phase 2 was to verify the efficiency of fire suppression in realistic fire scenarios using a Fine Water Spray system, and to find an optimum procedure for water application in a fire situation. Two reports have been made from the experiments in Phase 2, one Main Report, STF25 A94036, and the present Technical Report, STF25 A94037. The discussion and conclusions are given in the Main Report while this Technical Report gives a more thorough presentation of the experimental setup and methods used for calibration and calculation of measured values. In addition, a complete set of curves for each experiment is included.

  20. James Webb Space Telescope (JWST) and Star Formation

    Science.gov (United States)

    Greene, Thomas P.

    2010-01-01

    The 6.5-m aperture James Webb Space Telescope (JWST) will be a powerful tool for studying and advancing numerous areas of astrophysics. Its Fine Guidance Sensor, Near-Infrared Camera, Near-Infrared Spectrograph, and Mid-Infrared Instrument will be capable of making very sensitive, high angular resolution imaging and spectroscopic observations spanning 0.7 - 28 ?m wavelength. These capabilities are very well suited for probing the conditions of star formation in the distant and local Universe. Indeed, JWST has been designed to detect first light objects as well as to study the fine details of jets, disks, chemistry, envelopes, and the central cores of nearby protostars. We will be able to use its cameras, coronagraphs, and spectrographs (including multi-object and integral field capabilities) to study many aspects of star forming regions throughout the galaxy, the Local Group, and more distant regions. I will describe the basic JWST scientific capabilities and illustrate a few ways how they can be applied to star formation issues and conditions with a focus on Galactic regions.

  1. The ``One Archive'' for JWST

    Science.gov (United States)

    Greene, G.; Kyprianou, M.; Levay, K.; Sienkewicz, M.; Donaldson, T.; Dower, T.; Swam, M.; Bushouse, H.; Greenfield, P.; Kidwell, R.; Wolfe, D.; Gardner, L.; Nieto-Santisteban, M.; Swade, D.; McLean, B.; Abney, F.; Alexov, A.; Binegar, S.; Aloisi, A.; Slowinski, S.; Gousoulin, J.

    2015-09-01

    The next generation for the Space Telescope Science Institute data management system is gearing up to provide a suite of archive system services supporting the operation of the James Webb Space Telescope. We are now completing the initial stage of integration and testing for the preliminary ground system builds of the JWST Science Operations Center which includes multiple components of the Data Management Subsystem (DMS). The vision for astronomical science and research with the JWST archive introduces both solutions to formal mission requirements and innovation derived from our existing mission systems along with the collective shared experience of our global user community. We are building upon the success of the Hubble Space Telescope archive systems, standards developed by the International Virtual Observatory Alliance, and collaborations with our archive data center partners. In proceeding forward, the “one archive” architectural model presented here is designed to balance the objectives for this new and exciting mission. The STScI JWST archive will deliver high quality calibrated science data products, support multi-mission data discovery and analysis, and provide an infrastructure which supports bridges to highly valued community tools and services.

  2. Preparing the Public for JWST

    Science.gov (United States)

    Green, Joel D.; Smith, Denise A.; Lawton, Brandon L.; Jirdeh, Hussein; Meinke, Bonnie K.

    2016-01-01

    The James Webb Space Telescope is the successor to the Hubble Space Telescope. STScI and the Office of Public Outreach are committed to bringing awareness of the technology, the excitement, and the future science potential of this great observatory to the public, to educators and students, and to the scientific community, prior to its 2018 launch. The challenges in ensuring the high profile of JWST (understanding the infrared, the vast distance to the telescope's final position, and the unfamiliar science territory) requires us to lay the proper background. We currently engage the full range of the public and scientific communities using a variety of high impact, memorable initiatives, in combination with modern technologies to extend reach, linking the science goals of Webb to the ongoing discoveries being made by Hubble. We have injected Webb-specific content into ongoing E/PO programs: for example, simulated scientifically inspired but aesthetic JWST scenes, illustrating the differences between JWST and previous missions; partnering with high impact science communicators such as MinutePhysics to produce timely and concise content; educational materials in vast networks of schools through products like the Star Witness News.

  3. Progress by the JWST Science Working Group

    Science.gov (United States)

    Gardner, Jonathan P.

    2007-01-01

    The JWST Science Working Group recently published a comprehensive, top-level review of JWST science in the journal Space Science Reviews (Gardner et al. 2006, SSR, 123, 485). That review paper gives details of the 4 JWST science themes, and describes the design of the observatory and ground system. Since publication, the SWG, working with members of the astronomical community, has continued to develop the science case for JWST, giving more details in a series of white papers. The white paper topics include first light, galaxy surveys, AGN, supernovae, stellar populations, and exoplanets. The white papers are in various stages of completion. In this poster, I will review recent progress.

  4. AGN studies with JWST/MIRI

    NARCIS (Netherlands)

    Caputi, K.

    2015-01-01

    The forthcoming James Webb Space Telescope (JWST) will revolutionize galaxy evolution studies from the epoch of reionisation to the present day. In particular, a new era will be open for mid-IR astronomy, as the JWST Mid-Infrared Instrument (MIRI) will improve by an order of magnitude the sensitivit

  5. Preparing for JWST wavefront sensing and control operations

    Science.gov (United States)

    Perrin, Marshall D.; Acton, D. Scott; Lajoie, Charles-Philippe; Knight, J. Scott; Lallo, Matthew D.; Allen, Marsha; Baggett, Wayne; Barker, Elizabeth; Comeau, Thomas; Coppock, Eric; Dean, Bruce H.; Hartig, George; Hayden, William L.; Jordan, Margaret; Jurling, Alden; Kulp, Trey; Long, Joseph; McElwain, Michael W.; Meza, Luis; Nelan, Edmund P.; Soummer, Remi; Stansberry, John; Stark, Christopher; Telfer, Randal; Welsh, Andria L.; Zielinski, Thomas P.; Zimmerman, Neil T.

    2016-07-01

    The James Webb Space Telescopes segmented primary and deployable secondary mirrors will be actively con- trolled to achieve optical alignment through a complex series of steps that will extend across several months during the observatory's commissioning. This process will require an intricate interplay between individual wavefront sensing and control tasks, instrument-level checkout and commissioning, and observatory-level calibrations, which involves many subsystems across both the observatory and the ground system. Furthermore, commissioning will often exercise observatory capabilities under atypical circumstances, such as fine guiding with unstacked or defocused images, or planning targeted observations in the presence of substantial time-variable offsets to the telescope line of sight. Coordination for this process across the JWST partnership has been conducted through the Wavefront Sensing and Control Operations Working Group. We describe at a high level the activities of this group and the resulting detailed commissioning operations plans, supporting software tools development, and ongoing preparations activities at the Science and Operations Center. For each major step in JWST's wavefront sensing and control, we also explain the changes and additions that were needed to turn an initial operations concept into a flight-ready plan with proven tools. These efforts are leading to a robust and well-tested process and preparing the team for an efficient and successful commissioning of JWSTs active telescope.

  6. The James Webb Space Telescope (JWST), The First Light Machine

    Science.gov (United States)

    Stahl, H. Philip

    2013-01-01

    Scheduled to begin its 10 year mission after 2018, the James Webb Space Telescope (JWST) will search for the first luminous objects of the Universe to help answer fundamental questions about how the Universe came to look like it does today. At 6.5 meters in diameter, JWST will be the world s largest space telescope. This talk reviews science objectives for JWST and how they drive the JWST architecture, e.g. aperture, wavelength range and operating temperature. Additionally, the talk provides an overview of the JWST primary mirror technology development and fabrication status.

  7. JWST tunable filter imager: etalon prototype test results

    Science.gov (United States)

    Touahri, D.; Cameron, P.; Evans, C.; Greenberg, E.; Rowlands, N.; Scott, A.; Doyon, R.; Beaulieu, M.; Djazovski, O.

    2008-07-01

    We present the prototyping results and laboratory characterization of a narrow band Fabry-Perot etalon flight model which is one of the wavelength selecting elements of the Tunable Filter Imager. The latter is a part of the Fine Guidance Sensor which represents the Canadian contribution to NASA's James Webb Space Telescope. The unique design of this etalon provides the JWST observatory with the ability to image at 30 Kelvin, a 2.2'x2.2' portion of its field of view in a narrow spectral bandwidth of R~100 at any wavelength ranging between 1.6 and 4.9 μm (with a gap in coverage between 2.5 and 3.2 μm). Extensive testing has resulted in better understanding of the thermal properties of the piezoelectric transducers used as an actuation system for the etalon gap tuning. Good throughput, spectral resolution and contrast have been demonstrated for the full wavelength range.

  8. Key Exoplanets in the Era of JWST

    Science.gov (United States)

    Batalha, Natasha; Mandell, Avi; Lewis, Nikole K.; Pontoppidan, Klaus

    2017-01-01

    In 2018, exoplanet science will enter a new era with the launch of the James Webb Space Telescope (JWST). With JWST's observing power, several studies have sought to characterize how the instruments will perform and what atmospheric spectral features could theoretically be detected using transmission spectroscopy. With just two years left until launch, it is imperative that the exoplanet community begins to digest and integrate these studies into their observing plans and strategies. In order to encourage this and to allow all members of the community access to JWST simulations, we present here an open source tool for creating observation simulations of all observatory-supported time-series spectroscopy modes. We describe our tool, PandExo and use it to calculate the expected signal-to-noise ratio (SNR) for every confirmed planetary system with Jhours are needed to attain a SNR of 5 on key molecular absorption bands of H2O, CH4, and CO. We end by determining the number of planets (hot Jupiters, warm Neptunes, super-Earths, etc.) that are currently attainable with JWST.

  9. The fine-grained phase-space structure of cold dark matter haloes

    NARCIS (Netherlands)

    Vogelsberger, Mark; White, Simon D. M.; Helmi, Amina; Springel, Volker

    2008-01-01

    We present a new and completely general technique for calculating the fine-grained phase-pace structure of dark matter (DM) throughout the Galactic halo. Our goal is to understand this structure on the scales relevant for direct and indirect detection experiments. Our method is based on evaluating t

  10. Stress-Induced Precipitation of Fine γ-Phase and Thermodynamics Analysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The microstructures of a single crystal Ni-base superalloy with[001] orientation were observed by means of TEM. Results showed that the fine γ' particles were precipitated in the γ matrix channels during the tensile deformation of the alloy. Thermodynamics analysis indicated that the solubility of elements M(Al,Ta) within the γ matrix may be changed when the alloy was deformed by the external applied stress. The tensile stress reduced the solubility of elements Al and Ta so as to occur the over-saturation and agglomeration of them, which promoted the precipitation of fine γ'-phase in the γ matrix.

  11. Emerging Technologies and Outreach with JWST

    Science.gov (United States)

    Green, Joel D.; Smith, Denise A.; Meinke, Bonnie K.; Lawton, Brandon L.; Kenney, Jessica; Jirdeh, Hussein

    2017-06-01

    The James Webb Space Telescope (JWST), NASA’s next great observatory launching in October 2018, required a dozen new technologies to develop. How will we maintain the prestige and cultural impact of Hubble as the torch passes to Webb? Emerging technologies such as augmented and virtual reality bring the viewer into the data and the concept in previously unimaginable immersive detail. Adoption of mobile devices has expanded access to information for wide swaths of the public. Software like Worldwide Telescope to hardware like the Occulus Rift are providing new avenues for learning. If we develop materials properly tailored to this medium, we can reach more diverse audiences than ever before. STScI is pioneering some tools related to JWST for showcasing at AAS, and in local events, which I highlight here.

  12. WebbPSF for JWST and WFIRST

    Science.gov (United States)

    Long, Joseph D.; Perrin, Marshall D.; Zimmerman, Neil T.; Brooks, Keira

    2017-01-01

    Modeling a telescope's point spread function accurately is key to predicting its performance and extracting information from observations. WebbPSF is a flexible Python-based PSF simulation tool for JWST and WFIRST, developed at STScI. The WebbPSF-WFIRST module implements a model for the proposed Wide Field Instrument, as well as a proof-of-concept model for the Coronagraph Instrument. Since its announcement and public release at the Winter 2016 AAS, WebbPSF-WFIRST has been enhanced with the Cycle 6 design updates to the wide field instrument model. Additionally, the JupyterHub-based WFIRST Tools Server effort at STScI has provided access to these tools for dozens of users without the overhead of installing the software locally. For JWST, the optical models have been updated based on the latest test data and metrology for the instruments and the telescope flight hardware, including as-built mirror surface figures, variation between different field points, and updated optical budgets for in flight performance. WebbPSF has been checked against instrument test data from previous campaigns, and analysis of the PSF images taken during the JWST CV3 cryo-vac test campaign is currently underway.

  13. Exoplanets and debris disk imaging with JWST

    Science.gov (United States)

    Pueyo, Laurent; Soummer, Remi; Perrin, Marshall D.

    2017-06-01

    Dramatic progress in exoplanetary systems imaging has occurred since the first generation of space coronagraphs on HST (NICMOS, STIS, ACS). While HST remains at forefront of both exoplanetary and circumstellar disk science, ground-based instruments have improved by three orders of magnitudes over the past decade. JWST will extend the current state of the art with a larger set of superior coronagraphs and greater sensitivity across more than a factor of 10 in wavelength, making it extraordinarily capable for detailed imaging characterization of planets and disks. We will address specific questions about nearby exoplanetary systems, while also optimizing observing strategies across the breadth of JWST’s high-contrast imaging modes, as follows: (a) Deep, multi-wavelength observations of selected nearby stars hosting known debris disks & planets. We will use the NIRCam and MIRI coronagraphs across the full range of JWST wavelengths, and perhaps MIRI MRS spatially resolved spectroscopy. Each comprehensive dataset will support a variety of investigations addressing both disk characterization and exoplanet detection & characterization. (b) Characterization of Planetary Systems around Cool M Stars. We will observe young and dusty M dwarfs, to complement observations of the closer but older M dwarf samples under consideration by other GTO groups. JWST observations will dramatically exceed HST images in their ability to address questions about the properties of dust rings, while the more favorable contrast ratios of planets relative to M dwarf hosts will enable sensitivity to relatively low mass planetary companions.

  14. Observer's Interface for JWST Observation Specifications

    Science.gov (United States)

    Link, Miranda; Douglas, Robert; Moriarty, Christopher; Roman, Anthony

    2016-01-01

    In support of the launch of the James Webb Space Telescope, various teams at STScI (the Space Telescope Science Institute) have collaborated on how to re-structure the view of a an observing program within the Astronomer's Proposal Tool (APT) to accommodate for the differences between HST and JWST. For HST APT programs, the structure is visit-dominant, and there is one generic form for entering observing information that spans all instruments with their required fields and options. This can result in sometimes showing irrelevant fields to the user for a given observing goal. Also, the generation of mosaicked observations in HST requires the user to manually calculate the position of each tile within the mosaic, accounting for positional offsets and the roll of the telescope, which is a time consuming process. Now, for JWST programs in APT, the description of the observations has been segregated by instrument and mode into discrete observing templates. Each template's form allows instrument specific choices and displays of relevant information. APT will manually manage the number of visits needed to perform the observation. This is particularly useful for mosaics and dithering with JWST. For example, users will select how they would like a mosaic to be tiled at the observation level, and the visits are automatically created. In this, visits have been re-structured to be purely informational; all editing is done at the observation level. These options and concepts are illustrated to future users via the corresponding poster.

  15. JWST science instrument pupil alignment measurements

    Science.gov (United States)

    Kubalak, Dave; Sullivan, Joe; Ohl, Ray; Antonille, Scott; Beaton, Alexander; Coulter, Phillip; Hartig, George; Kelly, Doug; Lee, David; Maszkiewicz, Michael; Schweiger, Paul; Telfer, Randal; Te Plate, Maurice; Wells, Martyn

    2016-09-01

    NASA's James Webb Space Telescope (JWST) is a 6.5m diameter, segmented, deployable telescope for cryogenic IR space astronomy ( 40K). The JWST Observatory architecture includes the Optical Telescope Element (OTE) and the Integrated Science Instrument Module (ISIM) element that contains four science instruments (SI), including a guider. OSIM is a full field, cryogenic, optical simulator of the JWST OTE. It is the "Master Tool" for verifying the cryogenic alignment and optical performance of ISIM by providing simulated point source/star images to each of the four Science Instruments in ISIM. Included in OSIM is a Pupil Imaging Module (PIM) - a large format CCD used for measuring pupil alignment. Located at a virtual stop location within OSIM, the PIM records superimposed shadow images of pupil alignment reference (PAR) targets located in the OSIM and SI pupils. The OSIM Pupil Imaging Module was described by Brent Bos, et al, at SPIE in 2011 prior to ISIM testing. We have recently completed the third and final ISIM cryogenic performance verification test before ISIM was integrated with the OTE. In this paper, we describe PIM implementation, performance, and measurement results.

  16. Crystalline behaviors and phase transition during the manufacture of fine denier PA6 fibers

    Institute of Scientific and Technical Information of China (English)

    ZHANG ChengFeng; LIU YuHai; LIU ShaoXuan; LI HuiZhen; HUANG Kun; PAN QingHua; HUA XiaoHui; HAO ChaoWei; MA QingFang; LV ChangYou; LI WeiHong; YANG ZhanLan; ZHAO Ying; WANG DuJin; LAI GuoQiao; JIANG JianXiong; XU YiZhuang; WU JinGuang

    2009-01-01

    Recently we have successfully produced fine denier PA6 fibers by using additives containing lanthanide compounds.Meanwhile,crystallization and phase transition of PA6 fibers during spinning and drawing processes were investigated.During the spinning process,β phase crystal could be obtained In as-spun PA6 fibers which were produced with relatively high melt draw ratio,while γ phase crystal predominated when the melt draw ratio was relatively low.β phase crystal,whose behaviors ere similar with those of γ phase by FT-IR and XRD characterization,could be transformed to α form easily when PA6 fibers are immersed in boiling water.However,γ phase crystal of PA6 remains unchanged in boiling water.Thus,β and γ phase crystals of PA6 can be differentiated by the crystalline behaviors of PA6 fibers after treatment in boiling water.Further experiments demonstrate that the β phase can also be produced during a drawing process where a phase transformation from γ to α occurs.In other words,βphase may act as an intermediate state during the phase transformation.

  17. [Using barium fluoride fine particles as stationary phase for TLC/FTIR analysis].

    Science.gov (United States)

    Liu, Xi; Pan, Qing-hua; Ding, Jie; Zhu, Qing; He, An-qi; Yue, Shi-juan; Li, Xiao-pei; Hu, Li-ping; Xia, Jin-ming; Liu, Cui-ge; Wei, Yong-ju; Yu, Jiang; Yang, Zhan-lan; Zhu, Xi; Xu, Yi-zhuang; Wu, Jin-guang

    2011-07-01

    In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase such as silica gel etc. has strong absorption in FTIR spectrum and thus brings about severe interference in the detection of samples. To solve the problem, the authors propose to use barium fluoride fine particles as stationary phase of TLC plate. The reasons are as follows: Barium fluoride wafer has been extensively used as infrared window in FTIR experiments and it has no absorbance in an IR region between 4 000 and 800 cm'. As a matter of fact, the atomic mass of barium and fluoride is quite large, thus the normal vibration of BaF2 lattice is limited in far-IR region and low frequency part of mid-IR region. Therefore, the interference caused by IR absorption of stationary phase can be resolved if BaF2 is used as stationary phase of TLC plate. Moreover, BaF2 is quite stable and insolvable in water and most organic solvents and it will not be dissolved by mobile phase or react with samples in TLC separation. Additionally, decreasing the particle size of BaF2 is very important in TLC/FTIR analysis technique. The reason is two-fold: First, decreasing the particle size of stationary phase is helpful to improving the efficiency of separation by TLC plate; second, decreasing the size of BaFz particle can improve the quality of FTIR spectra by alleviating the problem of light scattering. By optimizing the synthetic conditions, fine particles of barium fluoride were obtained. SEM results indicate that the size of the BaF2 particles is around 500 nm. FTIR spectrum of the BaF2 particles shows that no absorption of impurity was observed. Moreover, the elevation of baseline caused by light scattering is insignificant. The authors have developed a new technique named "settlement volatilization method" to prepare TLC plate without polymeric adhesive that may bring about significant

  18. Mechanical properties of fine-grained dual phase low-carbon steels based on dynamic transformation

    Institute of Scientific and Technical Information of China (English)

    Haiwei Xu; Wangyue rang; Zuqing Sun

    2008-01-01

    The fine grained dual phase (FG-DP) steel with ferrite grains of 2-4.5 μm and martensite islands smaller than 3 μm was obtained through the mechanism of deformation-enhanced ferrite transformation (DEFT). Mechanical properties of the steel were tested at room temperature. The results indicated that with a similar volume fraction of martensite (about 20vol%), FG-DP steel ex-hibited a superior combination of higher strength and more rapid strain hardening at low strains compared with the coarse-grained dual phase (CG-DP) steel obtained by critical annealing. The combination of higher strength, large elongation, and more rapid strain hardening of FG-DP steel can be attributed to the fine ferrite grain and finely dispersed martensite islands. In addition, the uniformly distributed martensite islands in FG-DP steel have smaller interspaeing compared with that of CG-DP steel. So, at the initial plastic deformation stage, the plastic deformation of ferrite was restrained and more pronounced load was transferred from ferrite to marten-site. The plastic deformation of martensite in FG-DP steel started earlier.

  19. Comparing and Contrasting Detectors: JWST NIR vs HST WFC3

    Science.gov (United States)

    Rauscher, Bernard J.

    2015-01-01

    In many ways, WFC3s IR channel is a good indicator for what to expect with JWST. There are some differences, most of which should be beneficial in JWST- JWSTs lower operating temperature will freeze out charge traps that would affect WFC3. Benefits should include lower dark current, lower persistence, and better reciprocity- JWSTs more recent HgCdTe process has lower defect density. The benefits are as described above- JWST uses better indium barriers. The benefits should include fewer RC type pixels. One area where more study might be beneficial is stability. The detector electronics play a significant role in determining how stable a detector system is(v.s. bias drifts and photometry). JWSTs SIDECARs are completely WFC3s Ball electronics- Studies comparing the bias and photometric stability of WFC3 and JWST might be useful to informing data acquisition and calibration strategies for JWST.

  20. CHARACTERIZING TRANSITING EXOPLANET ATMOSPHERES WITH JWST

    Energy Technology Data Exchange (ETDEWEB)

    Greene, Thomas P. [NASA Ames Research Center, Space Science and Astrobiology Division, M.S. 245-6, Moffett Field, CA 94035 (United States); Line, Michael R.; Montero, Cezar; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Lustig-Yaeger, Jacob [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Luther, Kyle, E-mail: tom.greene@nasa.gov [Department of Physics, University of California, 366 LeConte Hall MC 7300, Berkeley, CA 94720 (United States)

    2016-01-20

    We explore how well spectra from the James Webb Space Telescope (JWST) will likely constrain bulk atmospheric properties of transiting exoplanets. We start by modeling the atmospheres of archetypal hot Jupiter, warm Neptune, warm sub-Neptune, and cool super-Earth planets with atmospheres that are clear, cloudy, or of high mean molecular weight (HMMW). Next we simulate the λ = 1–11 μm transmission and emission spectra of these systems for several JWST instrument modes for single-transit or single-eclipse events. We then perform retrievals to determine how well temperatures and molecular mixing ratios (CH{sub 4}, CO, CO{sub 2}, H{sub 2}O, NH{sub 3}) can be constrained. We find that λ = 1–2.5 μm transmission spectra will often constrain the major molecular constituents of clear solar-composition atmospheres well. Cloudy or HMMW atmospheres will often require full 1–11 μm spectra for good constraints, and emission data may be more useful in cases of sufficiently high F{sub p} and high F{sub p}/F{sub *}. Strong temperature inversions in the solar-composition hot-Jupiter atmosphere should be detectable with 1–2.5+ μm emission spectra, and 1–5+ μm emission spectra will constrain the temperature–pressure profiles of warm planets. Transmission spectra over 1–5+ μm will constrain [Fe/H] values to better than 0.5 dex for the clear atmospheres of the hot and warm planets studied. Carbon-to-oxygen ratios can be constrained to better than a factor of 2 in some systems. We expect that these results will provide useful predictions of the scientific value of single-event JWST spectra until its on-orbit performance is known.

  1. Status of the JWST sunshield and spacecraft

    Science.gov (United States)

    Arenberg, J.; Flynn, J.; Cohen, A.; Lynch, R.; Cooper, J.

    2016-07-01

    This paper reports on the development, manufacture and integration of the James Webb Space Telescope's sunshield and spacecraft. Both of these JWST elements have completed design and development testing. This paper will review basic architecture and roles of these systems. Also to be presented is the current state of manufacture, assembly integration and test. This paper will conclude with a look at the road ahead for each subsystem prior to integration with the integrated telescope and instrument elements at Northrop Grumman's Space Park facility in late 2017.

  2. Characterizing transiting exoplanet atmospheres with JWST

    CERN Document Server

    Greene, Thomas P; Montero, Cezar; Fortney, Jonathan J; Lustig-Yeager, Jacob; Luther, Kyle

    2015-01-01

    We explore how well James Webb Space Telescope (JWST) spectra will likely constrain bulk atmospheric properties of transiting exoplanets. We start by modeling the atmospheres of archetypal hot Jupiter, warm Neptune, warm sub-Neptune, and cool super-Earth planets with clear, cloudy, or high mean molecular weight atmospheres. Next we simulate the $\\lambda = 1 - 11$ $\\mu$m transmission and emission spectra of these systems for several JWST instrument modes for single transit and eclipse events. We then perform retrievals to determine how well temperatures and molecular mixing ratios (CH$_4$, CO, CO$_2$, H$_2$O, NH$_3$) can be constrained. We find that $\\lambda = 1 - 2.5$ $\\mu$m transmission spectra will often constrain the major molecular constituents of clear solar composition atmospheres well. Cloudy or high mean molecular weight atmospheres will often require full $1 - 11$ $\\mu$m spectra for good constraints, and emission data may be more useful in cases of sufficiently high $F_p$ and high $F_p/F_*$. Strong t...

  3. The fine-grained phase-space structure of Cold Dark Matter halos

    CERN Document Server

    Vogelsberger, Mark; Helmi, Amina; Springel, Volker

    2007-01-01

    We present a new and completely general technique for calculating the fine-grained phase-space structure of dark matter throughout the Galactic halo. Our goal is to understand this structure on the scales relevant for direct and indirect detection experiments. Our method is based on evaluating the geodesic deviation equation along the trajectories of individual DM particles. It requires no assumptions about the symmetry or stationarity of the halo formation process. In this paper we study general static potentials which exhibit more complex behaviour than the separable potentials studied previously. For ellipsoidal logarithmic potentials with a core, phase mixing is sensitive to the resonance structure, as indicated by the number of independent orbital frequencies. Regions of chaotic mixing can be identified by the very rapid decrease in the real space density of the associated dark matter streams. We also study the evolution of stream density in ellipsoidal NFW halos with radially varying isopotential shape,...

  4. A Retrieval Architecture for JWST Observations of Directly Imaged Exoplanets

    Science.gov (United States)

    Howe, Alex

    2017-06-01

    I present a new modeling and retrieval code for atmospheres of directly imaged exoplanets designed for use on JWST observations, extending my previous work on transiting planets. I perform example retrievals of temperature-pressure profiles, common molecular abundances, and basic cloud properties on existing lower-resolution spectra and on simulated JWST data using forward model emission spectra for planned NIRISS and NIRCam targets. From these results, I estimate the expected return on prospective JWST observations in information-theoretic terms using the mutual information metric.

  5. Changes in arbuscular mycorrhizal associations and fine root traits in sites under different plant successional phases in southern Brazil.

    Science.gov (United States)

    Zangaro, Waldemar; de Assis, Rafael Leandro; Rostirola, Leila Vergal; de Souza, Priscila Bochi; Gonçalves, Melissa Camargo; Andrade, Galdino; Nogueira, Marco Antonio

    2008-12-01

    Fine root morphological traits and distribution, arbuscular mycorrhizal (AM) fungi, soil fertility, and nutrient concentration in fine root tissue were compared in sites under different successional phases: grass plants, secondary forest, and mature forest in Londrina county, Paraná state, southern Brazil. Soil cores were collected randomly at the 0-10- and 10-20-cm depths in three quadrants (50 m2) in each site. Plants from the different successional stages displayed high differences in fine root distribution, fine root traits, and mycorrhizal root colonization. There were increases in the concentration of nutrients both in soil and fine roots and decrease of bulk soil density along the succession. The fine root biomass and diameter increased with the succession progress. The total fine root length, specific root length, root hair length, and root hair incidence decreased with the succession advance. Similarly, the mycorrhizal root colonization and the density of AM fungi spores in the soil decreased along the succession. Mycorrhizal root colonization and spore density were positively correlated with fine root length, specific root length, root hair length, root hair incidence, and bulk density and negatively correlated with fine root diameter and concentration of some nutrients both in soil and root tissues. Nutrient concentration in root tissue and in soil was positively correlated with fine root diameter and negatively correlated with specific root length, root hair length, and root hair incidence. These results suggest different adaptation strategies of plant roots for soil exploration and mineral acquisition among the different successional stages. Early successional stages displayed plants with fine root morphology and AM fungi colonization to improve the root functional efficiencies for uptake of nutrients and faster soil resource exploration. Late successional stages displayed plants with fine root morphology and mycorrhizal symbiosis for both a lower

  6. Periodicity extraction in the anuran auditory nerve. II: Phase and temporal fine structure.

    Science.gov (United States)

    Simmons, A M; Reese, G; Ferragamo, M

    1993-06-01

    Discharge patterns of single eighth nerve fibers in the bullfrog, Rana catesbeiana, were analyzed in response to signals consisting of multiple harmonics of a common, low-amplitude fundamental frequency. The signals were chosen to reflect the frequency and amplitude spectrum of the bullfrog's species-specific advertisement call. The phase spectrum of the signals was manipulated to produce envelopes that varied in their shapes from impulselike (sharp) to noiselike (flattened). Peripheral responses to these signals were analyzed by computing the autocorrelation functions of the spike trains and their power spectra, as well as by constructing period histograms over the time intervals of the low-frequency harmonics. In response to a phase aligned signal with an impulsive envelope, most fibers, regardless of their characteristic frequencies or place of origin within the inner ear, synchronize to the fundamental frequency of the signal. The temporal patterns of fiber discharge to these stimuli are not typically captured by that stimulus harmonic closet to the fiber characteristic frequency, as would be expected from a spectral coding mechanism for periodicity extraction, but instead directly reflect the periodicity of the stimulus envelope. Changing the phase relations between the individual harmonics constituting the signal produces changes in temporal discharge patterns of some fibers by shifting predominant synchronization away from the fundamental frequency to the low-frequency spectral peak in the complex stimuli. The proportion of fibers whose firing is captured by the fundamental frequency decreases as the waveform envelope becomes less impulselike. Fiber characteristic frequency is not highly correlated with the harmonic number to which synchronization is strongest. The higher-harmonic spectral fine structure of the signals is not reflected in fiber temporal response, regardless of the shape of the stimulus envelope, even for those harmonics within the range of

  7. Characterization of the JWST Pathfinder Mirror Dynamics Using the Center of Curvature Optical Assembly (CoCOA)

    Science.gov (United States)

    Wells, C.; Hadaway, J.; Olczak, G.; Cosentino, J.; Johnston, J.; Whitman, T.; Connolly, M.; Chaney, D.; Knight, J.; Telfer, R.

    2016-01-01

    The JWST (James Webb Space Telescope) Optical Telescope Element (OTE) consists of a 6.6 meter clear aperture, 18-segment primary mirror, all-reflective, three-mirror anastigmat operating at cryogenic temperatures. To verify performance of the primary mirror, a full aperture center of curvature optical null test is performed under cryogenic conditions in Chamber A at NASA Johnson Space Center using an instantaneous phase measuring interferometer. After phasing the mirrors during the JWST Pathfinder testing, the interferometer is utilized to characterize the mirror relative piston and tilt dynamics under different facility configurations. The correlation between the motions seen on detectors at the focal plane and the interferometer validates the use of the interferometer for dynamic investigations. The success of planned test hardware improvements will be characterized by the multi-wavelength interferometer (MWIF) at the Center of Curvature Optical Assembly (CoCOA).

  8. Characterization of the JWST Pathfinder mirror dynamics using the center of curvature optical assembly (CoCOA)

    Science.gov (United States)

    Wells, Conrad; Hadaway, James B.; Olczak, Gene; Cosentino, Joseph; Johnston, John D.; Whitman, Tony; Connolly, Mark; Chaney, David; Knight, J. Scott; Telfer, Randal

    2016-07-01

    The James Webb Space Telescope (JWST) Optical Telescope Element (OTE) consists of a 6.6 m clear aperture, 18 segment primary mirror, all-reflective, three-mirror anastigmat operating at cryogenic temperatures. To verify performance of the primary mirror, a full aperture center of curvature optical null test is performed under cryogenic conditions in Chamber A at the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) using an instantaneous phase measuring interferometer. After phasing the mirrors during the JWST Pathfinder testing, the interferometer is utilized to characterize the mirror relative piston and tilt dynamics under different facility configurations. The correlation between the motions seen on detectors at the focal plane and the interferometer validates the use of the interferometer for dynamic investigations. The success of planned test hardware improvements will be characterized by the multi-wavelength interferometer (MWIF) at the Center of Curvature Optical Assembly (CoCOA).

  9. AN IMAGE-PLANE ALGORITHM FOR JWST'S NON-REDUNDANT APERTURE MASK DATA

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, Alexandra Z. [Johns Hopkins University Department of Physics and Astronomy 3400 North Charles, Baltimore, MD 21218 (United States); Pueyo, Laurent; Sivaramakrishnan, Anand [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Lacour, Sylvestre [LESIA, CNRS/UMR-8109, Observatoire de Paris, UPMC, Université Paris Diderot 5 place Jules Janssen, 92195 Meudon (France)

    2015-01-10

    The high angular resolution technique of non-redundant masking (NRM) or aperture masking interferometry (AMI) has yielded images of faint protoplanetary companions of nearby stars from the ground. AMI on James Webb Space Telescope (JWST)'s Near Infrared Imager and Slitless Spectrograph (NIRISS) has a lower thermal background than ground-based facilities and does not suffer from atmospheric instability. NIRISS AMI images are likely to have 90%-95% Strehl ratio between 2.77 and 4.8 μm. In this paper we quantify factors that limit the raw point source contrast of JWST NRM. We develop an analytic model of the NRM point spread function which includes different optical path delays (pistons) between mask holes and fit the model parameters with image plane data. It enables a straightforward way to exclude bad pixels, is suited to limited fields of view, and can incorporate effects such as intra-pixel sensitivity variations. We simulate various sources of noise to estimate their effect on the standard deviation of closure phase, σ{sub CP} (a proxy for binary point source contrast). If σ{sub CP} < 10{sup –4} radians—a contrast ratio of 10 mag—young accreting gas giant planets (e.g., in the nearby Taurus star-forming region) could be imaged with JWST NIRISS. We show the feasibility of using NIRISS' NRM with the sub-Nyquist sampled F277W, which would enable some exoplanet chemistry characterization. In the presence of small piston errors, the dominant sources of closure phase error (depending on pixel sampling, and filter bandwidth) are flat field errors and unmodeled variations in intra-pixel sensitivity. The in-flight stability of NIRISS will determine how well these errors can be calibrated by observing a point source. Our results help develop efficient observing strategies for space-based NRM.

  10. Advanced cryogenic thermal switches for JWST

    Science.gov (United States)

    Bugby, David; Beres, Matthew; Stouffer, Charles; Rodriguez, Jose

    2005-08-01

    This paper describes two cryogenic thermal switches (CTSWs) under development for instruments on the James Webb Space Telescope (JWST). The first thermal switch was designed to extend the life of the solid H2 dewar for the 6 K Mid Infrared Instrument (MIRI) while the second thermal switch is needed for contamination and over-temperature control of three 35 K instruments on the Integrated Science Instrument Module (ISIM). In both cases, differential thermal expansion (DTE) between two materials having differing CTE values is the process that underpins the thermal switching. The patented DTE-CTSW design utilizes two metallic end-pieces, one cup-shaped and the other disc-shaped (both MIRI end-pieces are Al while ISIM uses an Al/Invar cup and an Al disc), joined by an axially centered Ultem rod, which creates a narrow, flat gap between the cup (rim) and disc. A heater is bonded to the rod center. Upon cooling one or both end-pieces, the rod contracts relative to the end-pieces and the gap closes, turning the CTSW ON. When the rod heater is turned on, the rod expands relative to the end-pieces and the gap opens, turning the CTSW OFF. During testing from 6-35 K, ON conductances of 0.3-12 W/K and OFF resistances greater than 2500 K/W were measured. Of particular importance at 6 K was the Al oxide layer, which was found to significantly decrease DTE-CTSW ON conductance when the mating surfaces were bare Al. When the mating surfaces were gold-plated, the adverse impact of the oxide layer was mitigated. This paper will describe both efforts from design through model correlation.

  11. Focus Groups for Solar System Investigations with the JWST

    Science.gov (United States)

    Hines, Dean C.; Milam, Stefanie N.; Stansberry, John; Hammel, Heidi B.; Sonneborn, George; Lunine, Jonathan; Rivkin, Andrew; Woodward, Charles; Norwood, Jim; Villanueva, Geronimo; Thomas, Cristina; Santos-Sanz, Pablo; Tiscareno, Matthew; Kestay, Laszlo; Nixon, Conor; Parker, Alex

    2014-11-01

    The unprecedented sensitivity and angular resolution of the James Webb Space Telescope (JWST) will make it NASA’s premier space-based facility for infrared astronomy. This 6.5-meter telescope, which is optimized for observations in the near and mid infrared, will be equipped with four state-of-the-art instruments that include imaging, spectroscopy, and coronagraphy. These instruments, along with the telescope’s moving target capabilities, will enable the infrared study of solar system objects with unprecedented detail. A new white paper (Norwood et al., 2014) provides a general overview of JWST observatory and instrument capabilities for Solar System science, and updates and expands upon an earlier study by Lunine et al. (2010). In order to fully realize the potential of JWST for Solar System observations, we have recently organized 10 focus groups to explore various science use cases in more detail on topics including: Asteroids, Comets, Giant Planets, Mars, Near Earth Objects, Occultations, Rings, Satellites, Titan, and Trans-Neptunian Objects. The findings from these groups will help guide the project as it develops and implements planning tools, observing templates, the data pipeline and archives so that they enable a broad range of Solar System Science investigations. The purpose of this presentation is to raise awareness of the JWST Solar System planning, and to invite participation of DPS members with our Focus Groups and other pre-launch activities.References:Lunine, J., Hammel, H., Schaller, E., Sonneborn, G., Orton, G., Rieke, G., and Rieke, M. 2010, JWST Planetary Observations within the Solar System, http://www.stsci.edu/jwst/doc-archive/white-papers.Norwood, J., Hammel, H., Milam, S.,Stansberry, J., Lunine, J., Chanover, N., Hines, D., Sonneborn, G., Tiscareno, M., Brown, M. and Ferruit, P., 2014, ArXiv e-prints, 1403.6845.

  12. The JWST science instrument payload: mission context and status

    Science.gov (United States)

    Greenhouse, Matthew A.

    2016-07-01

    The James Webb Space Telescope (JWST) is the scientific successor to the Hubble Space Telescope. It is a cryogenic infrared space observatory with a 25 m2 aperture (6 m class) telescope that will achieve diffraction limited angular resolution at a wavelength of 2 um. The science instrument payload includes four passively cooled near-infrared instruments providing broad- and narrow-band imagery, coronography, as well as multi-object and integral-field spectroscopy over the 0.6 Construction, integration and verification testing is underway in all areas of the program. The JWST is on schedule for launch during 2018.

  13. Microstructure and properties of liquid-phase sintered tungsten heavy alloys by using ultra-fine tungsten powders

    Institute of Scientific and Technical Information of China (English)

    于洋; 王尔德

    2004-01-01

    The microstructure and properties of liquid-phase sintered 93W-4.9Ni-2.1Fe tungsten heavy alloys using ultra-fine tungsten powders (medium particle size of 700 nm) and original tungsten powders (medium particle size of 3 μm) were investigated respectively. Commercial tungsten powders (original tungsten powders) were mechanically milled in a high-energy attritor mill for 35 h. Ultra-fine tungsten powders and commercial Ni, Fe powders were consolidated into green compacts by using CIP method and liquid-phase sintering at 1 465 ℃ for 30 min in the dissociated ammonia atmosphere. Liquid-phase sintered tungsten heavy alloys using ultra-fine tungsten powders exhibit full densification (above 99% in relative density) and higher strength and elongation compared with conventional liquidphase sintered alloys using original tungsten powders due to lower sintering temperature at 1 465 ℃ and short sintering time. The mechanical properties of sintered tungsten heavy alloy are found to be mainly dependent on the particles size of raw tungsten powders and liquid-phase sintering temperature.

  14. Spitzer/JWST Cross Calibration: IRAC Observations of Potential Calibrators for JWST

    Science.gov (United States)

    Carey, Sean J.; Gordon, Karl D.; Lowrance, Patrick; Ingalls, James G.; Glaccum, William J.; Grillmair, Carl J.; E Krick, Jessica; Laine, Seppo J.; Fazio, Giovanni G.; Hora, Joseph L.; Bohlin, Ralph

    2017-06-01

    We present observations at 3.6 and 4.5 microns using IRAC on the Spitzer Space Telescope of a set of main sequence A stars and white dwarfs that are potential calibrators across the JWST instrument suite. The stars range from brightnesses of 4.4 to 15 mag in K band. The calibration observations use a similar redundancy to the observing strategy for the IRAC primary calibrators (Reach et al. 2005) and the photometry is obtained using identical methods and instrumental photometric corrections as those applied to the IRAC primary calibrators (Carey et al. 2009). The resulting photometry is then compared to the predictions based on spectra from the CALSPEC Calibration Database (http://www.stsci.edu/hst/observatory/crds/calspec.html) and the IRAC bandpasses. These observations are part of an ongoing collaboration between IPAC and STScI investigating absolute calibration in the infrared.

  15. Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program

    Science.gov (United States)

    Stevenson, Kevin B.; Lewis, Nikole K.; Bean, Jacob L.; Beichman, Charles A.; Fraine, Jonathan; Kilpatrick, Brian M.; Krick, J. E.; Lothringer, Joshua D.; Mandell, Avi M.; Valenti, Jeff A.; Agol, Eric; Angerhausen, Daniel; Barstow, Joanna K.; Birkmann, Stephan M.; Burrows, Adam; Charbonneau, David; Cowan, Nicolas B.; Greene, Thomas P.; Line, Michael R.; Wakeford, Hanna R.

    2016-01-01

    The James Webb Space Telescope (JWST) will likely revolutionize transiting exoplanet atmospheric science, due to a combination of its capability for continuous, long duration observations and its larger collecting area, spectral coverage, and spectral resolution compared to existing space-based facilities. However, it is unclear precisely how well JWST will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. In this article, we describe a prefatory JWST Early Release Science (ERS) Cycle 1 program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful transiting exoplanet characterization programs in later cycles. We propose a multi-pronged approach wherein one aspect of the program focuses on observing transits of a single target with all of the recommended observing modes to identify and understand potential systematics, compare transmission spectra at overlapping and neighboring wavelength regions, confirm throughputs, and determine overall performances. In our search for transiting exoplanets that are well suited to achieving these goals, we identify 12 objects (dubbed community targets'') that meet our defined criteria. Currently, the most favorable target is WASP-62b because of its large predicted signal size, relatively bright host star, and location in JWST's continuous viewing zone. Since most of the community targets do not have well-characterized atmospheres, we recommend initiating preparatory observing programs to determine the presence of obscuring clouds/hazes within their atmospheres. Measurable spectroscopic features are needed to establish the optimal resolution and wavelength regions for exoplanet characterization. Other initiatives from our proposed ERS program include testing the instrument brightness limits and performing phase-curve observations. The latter are a unique challenge

  16. Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program

    Science.gov (United States)

    Stevenson, Kevin B.; Lewis, Nikole K.; Bean, Jacob L.; Beichman, Charles; Fraine, Jonathan; Kilpatrick, Brian M.; Krick, J. E.; Lothringer, Joshua D.; Mandell, Avi M.; Valenti, Jeff A.; Agol, Eric; Angerhausen, Daniel; Barstow, Joanna K.; Birkmann, Stephan M.; Burrows, Adam; Charbonneau, David; Cowan, Nicolas B.; Crouzet, Nicolas; Cubillos, Patricio E.; Curry, S. M.; Dalba, Paul A.; de Wit, Julien; Deming, Drake; Désert, Jean-Michel; Doyon, René; Dragomir, Diana; Ehrenreich, David; Fortney, Jonathan J.; García Muñoz, Antonio; Gibson, Neale P.; Gizis, John E.; Greene, Thomas P.; Harrington, Joseph; Heng, Kevin; Kataria, Tiffany; Kempton, Eliza M.-R.; Knutson, Heather; Kreidberg, Laura; Lafrenière, David; Lagage, Pierre-Olivier; Line, Michael R.; Lopez-Morales, Mercedes; Madhusudhan, Nikku; Morley, Caroline V.; Rocchetto, Marco; Schlawin, Everett; Shkolnik, Evgenya L.; Shporer, Avi; Sing, David K.; Todorov, Kamen O.; Tucker, Gregory S.; Wakeford, Hannah R.

    2016-09-01

    The James Webb Space Telescope (JWST) will likely revolutionize transiting exoplanet atmospheric science, due to a combination of its capability for continuous, long duration observations and its larger collecting area, spectral coverage, and spectral resolution compared to existing space-based facilities. However, it is unclear precisely how well JWST will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. In this article, we describe a prefatory JWST Early Release Science (ERS) Cycle 1 program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful transiting exoplanet characterization programs in later cycles. We propose a multi-pronged approach wherein one aspect of the program focuses on observing transits of a single target with all of the recommended observing modes to identify and understand potential systematics, compare transmission spectra at overlapping and neighboring wavelength regions, confirm throughputs, and determine overall performances. In our search for transiting exoplanets that are well suited to achieving these goals, we identify 12 objects (dubbed “community targets”) that meet our defined criteria. Currently, the most favorable target is WASP-62b because of its large predicted signal size, relatively bright host star, and location in JWST's continuous viewing zone. Since most of the community targets do not have well-characterized atmospheres, we recommend initiating preparatory observing programs to determine the presence of obscuring clouds/hazes within their atmospheres. Measurable spectroscopic features are needed to establish the optimal resolution and wavelength regions for exoplanet characterization. Other initiatives from our proposed ERS program include testing the instrument brightness limits and performing phase-curve observations. The latter are a unique challenge

  17. JWST observations of stellar occultations by solar system bodies and rings

    CERN Document Server

    Santos-Sanz, P; Pinilla-Alonso, N; Stansberry, J; Lin, Z-Y; Zhang, Z-W; Vilenius, E; Müller, Th; Ortiz, J L; Braga-Ribas, F; Bosh, A; Duffard, R; Lellouch, E; Tancredi, G; Young, L

    2015-01-01

    In this paper we investigate the opportunities provided by the James Webb Space Telescope (JWST) for significant scientific advances in the study of solar system bodies and rings using stellar occultations. The strengths and weaknesses of the stellar occultation technique are evaluated in light of JWST's unique capabilities. We identify several possible JWST occultation events by minor bodies and rings, and evaluate their potential scientific value. These predictions depend critically on accurate a priori knowledge of the orbit of JWST near the Sun-Earth Lagrange-point 2 (L2). We also explore the possibility of serendipitous stellar occultations by very small minor bodies as a by-product of other JWST observing programs. Finally, to optimize the potential scientific return of stellar occultation observations, we identify several characteristics of JWST's orbit and instrumentation that should be taken into account during JWST's development.

  18. Ultra-fine grained microstructure of metastable beta Ti-15Mo alloy and its effects on the phase transformations

    Science.gov (United States)

    Václavová, K.; Stráský, J.; Zháňal, P.; Veselý, J.; Polyakova, V.; Semenova, I.; Janeček, M.

    2017-05-01

    Processing of metastable titanium alloys by severe plastic deformation provides an opportunity to achieve exceptional grain refinement, to enhance the strength and to affect phase transformations occurring during thermal treatment. The main aim of this study is to investigate the microstructure of ultra-fine grained (UFG) material and effect of microstructural changes on phase transformations in metastable β-Ti alloy Ti-15Mo. Metastable β-Ti alloys are currently the most studied Ti-based materials with prospective use in medicine. Ti-15Mo alloy after solution treatment contains metastable β-phase. Metastable ω-phase and stable α-phase particles are formed upon annealing,. Solution treated Ti-15Mo alloy was deformed by high pressure torsion (HPT) at room temperature. Severely deformed structure after HPT with grain size of ~200 nm was studied by transmission electron microscopy. In-situ electrical resistance measurements showed significant changes in undergoing phase transformations when compared to coarse-grained (CG) material. Scanning electron microscopy revealed heterogeneous precipitation of α-particles at grain boundaries (GB). Due to the high density of GBs in UFG structure, these precipitates are very fine and equiaxed. The study demonstrates that SPD is capable of enhancing mechanical properties due to grain refinement and via affecting precipitation processes in metastable β-Ti alloys.

  19. Planning JWST NIRSpec MSA spectroscopy using NIRCam pre-images

    Science.gov (United States)

    Beck, Tracy L.; Ubeda, Leonardo; Kassin, Susan A.; Gilbert, Karoline; Karakla, Diane M.; Reid, I. N.; Blair, William P.; Keyes, Charles D.; Soderblom, D. R.; Peña-Guerrero, Maria A.

    2016-07-01

    The Near-Infrared Spectrograph (NIRSpec) is the work-horse spectrograph at 1-5microns for the James Webb Space Telescope (JWST). A showcase observing mode of NIRSpec is the multi-object spectroscopy with the Micro-Shutter Arrays (MSAs), which consist of a quarter million tiny configurable shutters that are 0. ''20×0. ''46 in size. The NIRSpec MSA shutters can be opened in adjacent rows to create flexible and positionable spectroscopy slits on prime science targets of interest. Because of the very small shutter width, the NIRSpec MSA spectral data quality will benefit significantly from accurate astrometric knowledge of the positions of planned science sources. Images acquired with the Hubble Space Telescope (HST) have the optimal relative astrometric accuracy for planning NIRSpec observations of 5-10 milli-arcseconds (mas). However, some science fields of interest might have no HST images, galactic fields can have moderate proper motions at the 5mas level or greater, and extragalactic images with HST may have inadequate source information at NIRSpec wavelengths beyond 2 microns. Thus, optimal NIRSpec spectroscopy planning may require pre-imaging observations with the Near-Infrared Camera (NIRCam) on JWST to accurately establish source positions for alignment with the NIRSpec MSAs. We describe operational philosophies and programmatic considerations for acquiring JWST NIRCam pre-image observations for NIRSpec MSA spectroscopic planning within the same JWST observing Cycle.

  20. Titan Science with the James Webb Space Telescope (JWST)

    CERN Document Server

    Nixon, Conor A; Adamkovics, Mate; Bezard, Bruno; Bjoraker, Gordon L; Cornet, Thomas; Hayes, Alexander G; Lellouch, Emmanuel; Lemmon, Mark T; Lopez-Puertas, Manuel; Rodriguez, Sebastien; Sotin, Christophe; Teanby, Nicholas A; Turtle, Elizabeth P; West, Robert A

    2015-01-01

    The James Webb Space Telescope (JWST), scheduled for launch in 2018, is the successor to the Hubble Space Telescope (HST) but with a significantly larger aperture (6.5 m) and advanced instrumentation focusing on infrared science (0.6-28.0 $\\mu$m ). In this paper we examine the potential for scientific investigation of Titan using JWST, primarily with three of the four instruments: NIRSpec, NIRCam and MIRI, noting that science with NIRISS will be complementary. Five core scientific themes are identified: (i) surface (ii) tropospheric clouds (iii) tropospheric gases (iv) stratospheric composition and (v) stratospheric hazes. We discuss each theme in depth, including the scientific purpose, capabilities and limitations of the instrument suite, and suggested observing schemes. We pay particular attention to saturation, which is a problem for all three instruments, but may be alleviated for NIRCam through use of selecting small sub-arrays of the detectors - sufficient to encompass Titan, but with significantly fas...

  1. Synergy with HST and JWST Data Management Systems

    Science.gov (United States)

    Greene, Gretchen; Space Telescope Data Management Team

    2014-01-01

    The data processing and archive systems for the JWST will contain a petabyte of science data and the best news is that users will have fast access to the latest calibrations through a variety of new services. With a synergistic approach currently underway with the STScI science operations between the Hubble Space Telescope and James Webb Space Telescope data management subsystems (DMS), operational verification is right around the corner. Next year the HST archive will provide scientists on-demand fully calibrated data products via the Mikulski Archive for Space Telescopes (MAST), which takes advantage of an upgraded DMS. This enhanced system, developed jointly with the JWST DMS is based on a new CONDOR distributed processing system capable of reprocessing data using a prioritization queue which runs in the background. A Calibration Reference Data System manages the latest optimal configuration for each scientific instrument pipeline. Science users will be able to search and discover the growing MAST archive calibrated datasets from these missions along with the other multiple mission holdings both local to MAST and available through the Virtual Observatory. JWST data systems will build upon the successes and lessons learned from the HST legacy and move us forward into the next generation of multi-wavelength archive research.

  2. Astrophysics in the Next Decade: JWST and Concurrent Facilities

    CERN Document Server

    Thronson, Harley A; Tielens, Alexander; The James Webb Space Telescope and Concurrent Facilities

    2009-01-01

    NASA’s James Webb Space Telescope (JWST), planned for operation in about five years, will have the capability to investigate – and answer – some of the most challenging questions in astronomy. Although motivated and designed to study the very early Universe, the performance of the observatory’s instruments over a very wide wavelength range will allow the world’s scientific community unequaled ability to study cosmic phenomena as diverse as small bodies in the Solar System and the formation of galaxies. As part of preparation to use JWST, a conference was held in Tucson, Arizona in 2007 that brought together astronomers from around the world to discuss the mission, other major facilities that will operate in the coming decade, and major scientific goals for them. This book is a compilation of those presentations by some of the leading researchers from all branches of astronomy. This book also includes a "pre-history" of JWST, describing the lengthy process and some of the key individuals that initiat...

  3. Improving JWST Coronagraphic Performance with Accurate Image Registration

    Science.gov (United States)

    Van Gorkom, Kyle; Pueyo, Laurent; Lajoie, Charles-Philippe; JWST Coronagraphs Working Group

    2016-06-01

    The coronagraphs on the James Webb Space Telescope (JWST) will enable high-contrast observations of faint objects at small separations from bright hosts, such as circumstellar disks, exoplanets, and quasar disks. Despite attenuation by the coronagraphic mask, bright speckles in the host’s point spread function (PSF) remain, effectively washing out the signal from the faint companion. Suppression of these bright speckles is typically accomplished by repeating the observation with a star that lacks a faint companion, creating a reference PSF that can be subtracted from the science image to reveal any faint objects. Before this reference PSF can be subtracted, however, the science and reference images must be aligned precisely, typically to 1/20 of a pixel. Here, we present several such algorithms for performing image registration on JWST coronagraphic images. Using both simulated and pre-flight test data (taken in cryovacuum), we assess (1) the accuracy of each algorithm at recovering misaligned scenes and (2) the impact of image registration on achievable contrast. Proper image registration, combined with post-processing techniques such as KLIP or LOCI, will greatly improve the performance of the JWST coronagraphs.

  4. Simulating Exoplanet Transit and Eclipse Observations with JWST

    Science.gov (United States)

    Greene, Tom

    2011-01-01

    The James Webb Space Telescope (JWST) will be a nearly ideal machine for acquiring the transmission and emission spectra of transiting exoplanets over its large wavelength range 0.7 - 28 microns. The NIRSpec, NIRCam, nTFI, and MIRI instruments will have spectroscopic capabilities that span spectral resolutions from 20 - 3000 and can cover up to 2 - 3 octaves in wavelength simultaneously. This will allow observing multiple molecular features at once, facilitating the separation of atmospheric temperature and abundance effects on spectra. Many transiting planets will also be able to be observed with both transmission and eclipse spectroscopy, providing further insights and constraints on planetary thermal structures and energy transport. Simulated JWST spectra of planets ranging from mini-Neptunes to gas giants will be presented. These simulations include planets ranging from mini-Neptunes to gas giants will be presented. These simulations include current best estimates of actual instrument throughput, resolution, spectral range, systematic noise, and random noise terms. They show that JWST will be able to determine the atmospheric parameters of a wide variety of planets, often when observing only one or a few transit or eclipse event sequences. The thermal emissions of rocky super-Earths will also be quickly detectable via mid-IR eclipse observations if such planets are found around nearby M star hosts beforehand.

  5. Characterizing Transiting Planets with JWST Spectra: Simulations and Retrievals

    Science.gov (United States)

    Greene, Tom; Line, Michael; Fortney, Jonathan

    2015-01-01

    There are now well over a thousand confirmed exoplanets, ranging from hot to cold and large to small worlds. JWST spectra will provide much more detailed information on the molecular constituents, chemical compositions, and thermal properties of the atmospheres of transiting planets than is now known. We explore this by modeling clear, cloudy,and high mean molecular weight atmospheres of typical hot Jupiter, warm Neptune, warm sub-Neptune, and cool super-Earth planets and then simulating their JWST transmission and emission spectra. These simulations were performed for several JWST instrument modes over 1 - 11 microns and incorporate realistic signal and noise components. We then performed state-of the art retrievals to determine how well temperatures and abundances (CO, CO2, H2O, NH3) will be constrained and over what pressures for these different planet types. Using these results, we appraise what instrument modes will be most useful for determining what properties of the different planets, and we assess how well we can constrain their compositions, CO ratios, and temperature profiles.

  6. Origin of the Universe: From the First Stars to Planets with JWST

    Science.gov (United States)

    Clampin, Mark

    2008-01-01

    The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments. JWST's primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, protoplanetary systems, and the formation of evolution of planetary systems. We will review the motivations for JWST's science goals in the context of recent Hubble Space Telescope, and Spitzer Space Telescope observations and review the status of the JWST Observatory.

  7. A low-phase-noise ring oscillator with coarse and fine tuning in a standard CMOS process

    Science.gov (United States)

    Haijun, Gao; Lingling, Sun; Xiaofei, Kuang; Liheng, Lou

    2012-07-01

    A low-phase-noise wideband ring oscillator with coarse and fine tuning techniques implemented in a standard 65 nm CMOS process is presented. Direct frequency modulation in the ring oscillator is analyzed and a switched capacitor array is introduced to produce the lower VCO gain required to suppress this effect. A two-dimensional high-density stacked MOM-capacitor was adopted as the switched capacitor to make the proposed ring VCO compatible with standard CMOS processes. The designed ring VCO exhibits an output frequency from 480 to 1100 MHz, resulting in a tuning range of 78%, and the measured phase noise is -120 dBc/Hz @ 1 MHz at 495 MHz output. The VCO core consumes 3.84 mW under a 1.2 V supply voltage and the corresponding FOM is -169 dBc/Hz.

  8. Graphene-based fine-tunable optical delay line for optical beamforming in phased-array antennas.

    Science.gov (United States)

    Tatoli, Teresa; Conteduca, Donato; Dell'Olio, Francesco; Ciminelli, Caterina; Armenise, Mario N

    2016-06-01

    The design of an integrated graphene-based fine-tunable optical delay line on silicon nitride for optical beamforming in phased-array antennas is reported. A high value of the optical delay time (τg=920  ps) together with a compact footprint (4.15  mm2) and optical loss antennas. The delay line includes two graphene-based Mach-Zehnder interferometer switches and two vertically stacked microring resonators between which a graphene capacitor is placed. The tuning range is obtained by varying the value of the voltage applied to the graphene electrodes, which controls the optical path of the light propagation and therefore the delay time. The graphene provides a faster reconfigurable time and low values of energy dissipation. Such significant advantages, together with a negligible beam-squint effect, allow us to overcome the limitations of conventional RF beamformers. A highly efficient fine-tunable optical delay line for the beamsteering of 20 radiating elements up to ±20° in the azimuth direction of a tile in a phased-array antenna of an X-band synthetic aperture radar has been designed.

  9. Developing an instrument simulator: experience feedback from the JWST/NIRSpec and VLT/MUSE simulators

    Science.gov (United States)

    Jarno, Aurélien; Piqueras, Laure; Bacon, Roland; Ferruit, Pierre; Legros, Emeline; Pécontal-Rousset, Arlette; Gnata, Xavier; Streicher, Ole; Weilbacher, Peter

    2012-09-01

    The Centre de Recherche Astrophysique de Lyon (CRAL) has recently developed two instrument simulators for spectrographic instruments. They are based on Fourier optics, and model the whole chain of acquisition, taking into account both optical aberrations and diffraction effects, by propagating a wavefront through the instrument, according to the Fourier optics concept. One simulates the NIRSpec instrument, a near-infrared multi-object spectrograph for the future James Webb Space Telescope (JWST). The other one models the Multi Unit Spectroscopic Explorer (MUSE) instrument, a second-generation integral-field spectrograph for the Very Large Telescope (VLT). The two simulators have been developed in different contexts (subcontracted versus developed internally), and for very different instruments (space-based versus ground-based), which strengthen the CRAL experience. This paper describes the lessons learned while developing these simulators: development methods, phasing with the project, points to focus on, getting data, interacting with scientists and users, etc.

  10. The Impact of JWST Broadband Filter Choice on Photometric Redshift Estimation

    DEFF Research Database (Denmark)

    Bisigello, L.; Caputi, K. I.; Colina, L.;

    2016-01-01

    The determination of galaxy redshifts in the James Webb Space Telescope's (JWST) blank-field surveys will mostly rely on photometric estimates, based on the data provided by JWST's Near-Infrared Camera (NIRCam) at 0.6–5.0 μm and Mid Infrared Instrument (MIRI) at λ 5.0 μm. In this work we analyze ...

  11. Can JWST Follow Up on Gravitational-Wave Detections?

    Science.gov (United States)

    Kohler, Susanna

    2016-02-01

    Bitten by the gravitational-wave bug? While we await Thursdays press conference, heres some food for thought: if LIGO were able to detect gravitational waves from compact-object mergers, how could we follow up on the detections? A new study investigates whether the upcoming James Webb Space Telescope (JWST) will be able to observe electromagnetic signatures of some compact-object mergers.Hunting for MergersStudying compact-object mergers (mergers of black holes and neutron stars) can help us understand a wealth of subjects, like high-energy physics, how matter behaves at nuclear densities, how stars evolve, and how heavy elements in the universe were created.The Laser Interferometer Gravitational-Wave Observatory (LIGO) is searching for the signature ripples in spacetime identifying these mergers, but gravitational waves are squirrelly: LIGO will only be able to localize wave sources to tens of square degrees. If we want to find out more about any mergers LIGO discovers in gravitational waves, well need a follow-up search for electromagnetic counterparts with other observatories.The Kilonova KeyOne possible electromagnetic counterpart is kilonovae, explosions that can be produced during a merger of a binary neutron star or a neutron starblack hole system. If the neutron star is disrupted during the merger, some of the hot mass is flung outward and shines brightly by radioactive decay.Kilonovae are especially promising as electromagnetic counterparts to gravitational waves for three reasons:They emit isotropically, so the number of observable mergers isnt limited by relativistic beaming.They shine for a week, giving follow-up observatories time to search for them.The source location can beeasily recovered.The only problem? We dont currently have any sensitive survey instruments in the near-infrared band (where kilonova emission peaks) that can provide coverage over tens of square degrees. Luckily, we will soon have just the thing: JWST, launching in 2018!JWSTs

  12. The self-coherent camera as a focal plane fine phasing sensor

    Science.gov (United States)

    Janin-Potiron, P.; Martinez, P.; Baudoz, P.; Carbillet, M.

    2016-08-01

    Context. Direct imaging of Earth-like exoplanets requires very high contrast imaging capability and high angular resolution. Primary mirror segmentation is a key technological solution for large-aperture telescopes because it opens the path toward significantly increasing the angular resolution. The segments are kept aligned by an active optics system that must reduce segment misalignments below tens of nm rms to achieve the high optical quality required for astronomical science programs. Aims: The development of cophasing techniques is mandatory for the next generation of space- and ground-based segmented telescopes, which both share the need for increasing spatial resolution. We propose a new focal plane cophasing sensor that exploits the scientific image of a coronagraphic instrument to retrieve simultaneously piston and tip-tilt misalignments. Methods: The self-coherent camera phasing sensor (SCC-PS) adequately combines the SCC properties to segmented telescope architectures with adapted segment misalignment estimators and image processing. An overview of the system architecture, and a thorough performance and sensitivity analysis, including a closed-loop efficiency, are presented by means of numerical simulations. Results: The SCC-PS estimates simultaneously piston and tip-tilt misalignments and corrects them in closed-loop operation in a few iterations. As opposed to numerous phasing sensor concepts the SCC-PS does not require any a priori on the signal at the segment boundaries or any dedicated optical path. We show that the SCC-PS has a moderate sensitivity to misalignments, virtually none to pupil shear, and is by principle insensitive to segment gaps and edge effects. Primary mirror phasing can be achieved with a relatively bright natural guide star with the SCC-PS. Conclusions: The SCC-PS is a noninvasive concept and an efficient phasing sensor from the image domain. It is an attractive candidate for segment cophasing at the instrument level or

  13. Phase-field simulation of formation of cellular dendrites and fine cellular structures at high growth velocities during directional solidification of Ti56Al44 alloy

    Institute of Scientific and Technical Information of China (English)

    LI Xin-zhong; GUO Jing-jie; SU Yan-qing; WU Shi-ping; FU Heng-zhi

    2005-01-01

    A phase-field model whose free energy of the solidification system derived from the Calphad thermodynamic modeling of phase diagram was used to simulate formation of cellular dendrites and fine cellular structures of Ti56Al44 alloy during directional solidification at high growth velocities. The liquid-solid phase transition of L→β was chosen. The dynamics of breakdown of initially planar interfaces into cellular dendrites and fine cellular structures were shown firstly at two growth velocities. Then the unidirectional free growths of two initial nucleations evolving to fine cellular dendrites were investigated. The tip splitting phenomenon is observed and the negative temperature gradient in the liquid represents its supercooling directional solidification. The simulation results show the realistic evolution of interfaces and microstructures and they agree with experimental one.

  14. Supermassive Dark Stars: Detectable in JWST

    CERN Document Server

    Freese, Katherine; Spolyar, Douglas; Valluri, Monica; Bodenheimer, Peter

    2010-01-01

    The first phase of stellar evolution in the history of the Universe may be Dark Stars, powered by dark matter heating rather than by nuclear fusion. Weakly Interacting Massive Particles, which may be their own antipartners, collect inside the first stars and annihilate to produce a heat source that can power the stars for millions to billions of years. In this paper we show that these objects can grow to be supermassive dark stars (SMDS) with masses $\\gtrsim (10^5-10^7) \\msun$. The growth continues as long as dark matter heating persists, since dark stars are large and cool (surface temperature $\\lesssim 5\\times 10^4$K) and do not emit enough ionizing photons to prevent further accretion of baryons onto the star. The dark matter may be provided by two mechanisms: (1) gravitational attraction of dark matter particles on a variety of orbits not previously considered, and (2) capture of WIMPs due to elastic scattering. Once the dark matter fuel is exhausted, the SMDS becomes a heavy main sequence star; these sta...

  15. The self-coherent camera as a focal plane fine phasing sensor

    CERN Document Server

    Janin-Potiron, Pierre; Baudoz, Pierre; Carbillet, Marcel

    2016-01-01

    Direct imaging of Earth-like exoplanets requires high contrast imaging capability and high angular resolution. Primary mirror segmentation is a key technological solution for large-aperture telescopes because it opens the path toward significantly increasing the angular resolution. The segments are kept aligned by an active optics system that must reduce segment misalignments below tens of nm RMS to achieve the high optical quality required for astronomical science programs. The development of cophasing techniques is mandatory for the next generation of space- and ground-based segmented telescopes, which both share the need for increasing spatial resolution. We propose a new focal plane cophasing sensor that exploits the scientific image of a coronagraphic instrument to retrieve simultaneously piston and tip-tilt misalignments. The self-coherent camera phasing sensor (SCC-PS) adequately combines the SCC properties to segmented telescope architectures with adapted segment misalignment estimators and image proc...

  16. Exoplanets with JWST: degeneracy, systematics and how to avoid them

    Science.gov (United States)

    Barstow, Joanna K.; Irwin, Patrick G. J.; Kendrew, Sarah; Aigrain, Suzanne

    2016-07-01

    The high sensitivity and broad wavelength coverage of the James Webb Space Telescope will transform the field of exoplanet transit spectroscopy. Transit spectra are inferred from minute, wavelength-dependent variations in the depth of a transit or eclipse as the planet passes in front of or is obscured by its star, and the spectra contain information about the composition, structure and cloudiness of exoplanet atmospheres. Atmospheric retrieval is the preferred technique for extracting information from these spectra, but the process can be confused by astrophysical and instrumental systematic noise. We present results of retrieval tests based on synthetic, noisy JWST spectra, for clear and cloudy planets and active and inactive stars. We find that the ability to correct for stellar activity is likely to be a limiting factor for cloudy planets, as the effects of unocculted star spots may mimic the presence of a scattering slope due to clouds. We discuss the pros and cons of the available JWST instrument combinations for transit spectroscopy, and consider the effect of clouds and aerosols on the spectra. Aerosol high in a planet's atmosphere obscures molecular absorption features in transmission, reducing the information content of spectra in wavelength regions where the cloud is optically thick. We discuss the usefulness of particular wavelength regions for identifying the presence of cloud, and suggest strategies for solving the highly-degenerate retrieval problem for these objects.

  17. Unique Spectroscopy and Imaging of Mars with JWST

    CERN Document Server

    Villanueva, Geronimo L; Clancy, Todd R; Encrenaz, Therese; Fouchet, Thierry; Hartogh, Paul; Lellouch, Emmanuel; Lopez-Valverde, Miguel A; Mumma, Michael J; Novak, Robert E; Smith, Michael D; Vandaele, Ann-Carine; Wolff, Michael J; Ferruit, Pierre; Milam, Stefanie N

    2015-01-01

    In this document, we summarize the main capabilities of the James Webb Space Telescope (JWST) for performing observations of Mars. The distinctive vantage point of JWST at the Sun-Earth Lagrange point (L2) will allow sampling the full observable disk, permitting the study of short-term phenomena, diurnal processes (across the East-West axis) and latitudinal processes between the hemispheres (including seasonal effects) with excellent spatial resolutions (0.07 arcsec at 2 {\\mu}m). Spectroscopic observations will be achievable in the 0.7-5 {\\mu}m spectral region with NIRSpec at a maximum resolving power of 2700, and with 8000 in the 1-1.25 {\\mu}m range. Imaging will be attainable with NIRCam at 4.3 {\\mu}m and with two narrow filters near 2 {\\mu}m, while the nightside will be accessible with several filters in the 0.5 to 2 {\\mu}m. Such a powerful suite of instruments will be a major asset for the exploration and characterization of Mars. Some science cases include the mapping of the water D/H ratio, investigatio...

  18. Bringing the Science of JWST to the Public

    Science.gov (United States)

    Green, Joel D.; Smith, Denise A.; Lawton, Brandon L.; Meinke, Bonnie K.; Jirdeh, Hussein

    2017-01-01

    The James Webb Space Telescope is the successor to the Hubble Space Telescope. STScI and the Office of Public Outreach are committed to bringing awareness of the technology, the excitement, and the future science potential of this great observatory to the public and to the scientific community, prior to its 2018 launch. The challenges in ensuring the high profile of JWST (understanding the infrared, the vast distance to the telescope's final position, and the unfamiliar science territory) requires us to lay the proper background, particularly in the area of spectroscopy. We currently engage the full range of the public and scientific communities using a variety of high impact, memorable initiatives, in combination with modern technologies to extend reach, linking the science goals of Webb to the ongoing discoveries being made by Hubble. Webbtelescope.org, the public hub for scientific information related to JWST, is now open. We have injected Webb-specific content into ongoing outreach programs: for example, partnering with high impact science communicators such as MinutePhysics to produce timely and concise content; partnering with musicians and artists to link science and art. Augmented reality apps showcase NASA’s telescopes in a format usable by anyone with a smartphone, and visuals from increasingly affordable 3D VR technologies.

  19. High Contrast Imaging with the JWST NIRCAM Coronagraph

    Science.gov (United States)

    Green, Joseph J.; Beichman, Charles; Basinger, Scott A.; Horner, Scott; Meyer, Michael; Redding, David C.; Rieke, Marcia; Trauger, John T.

    2005-01-01

    Relative to ground-based telescopes, the James Webb Space Telescope (JWST) will have a substantial sensitivity advantage in the 2.2-5pm wavelength range where brown dwarfs and hot Jupiters are thought to have significant brightness enhancements. To facilitate high contrast imaging within this band, the Near-Infrared Camera (NIRCAM) will employ a Lyot coronagraph with an array of band-limited image-plane occulting spots. In this paper, we provide the science motivation for high contrast imaging with NIRCAM, comparing its expected performance to that of the Keck, Gemini and 30 m (TMT) telescopes equipped with Adaptive Optics systems of different capabilities. We then describe our design for the NIRCAM coronagraph that enables imaging over the entire sensitivity range of the instrument while providing significant operational flexibility. We describe the various design tradeoffs that were made in consideration of alignment and aberration sensitivities and present contrast performance in the presence of JWST's expected optical aberrations. Finally we show an example of a that can provide 10-5 companion sensitivity at sub-arcsecond separations.

  20. Observing Planetary Rings with JWST: Science Justification and Observation Requirements

    CERN Document Server

    Tiscareno, Matthew S; Cuzzi, Jeffrey N; de Pater, Imke; Hamilton, Douglas P; Hedman, Matthew M; Nicholson, Philip D; Showalter, Mark R; Tamayo, Daniel; Verbiscer, Anne J

    2014-01-01

    The rings that adorn the four giant planets are of prime importance as accessible natural laboratories for disk processes, as clues to the origin and evolution of planetary systems, and as shapers as well as detectors of their planetary environments. The retinue of small moons accompanying all known ring systems are intimately connected as both sources and products, as well as shepherds and perturbers, of the rings. Leading sources of data on ring systems include spacecraft such as Cassini and Voyager, but also space telescopes such as Hubble and Spitzer as well as ground-based telescopes. The James Webb Space Telescope (JWST) is being prepared for launch in 2018 to begin a planned five-year mission. JWST will have the capability to observe solar system objects as close as Mars. Although most of the hardware is already designed and under construction if not completed, work continues on the development of operations guidelines and software and the completion of calibration tasks. The purpose of this white pape...

  1. Large Space Optics: From Hubble to JWST and Beyond

    Science.gov (United States)

    Stahl, H. Philip

    2008-01-01

    If necessity truly is the mother of invention, then advances in lightweight space mirror technology have been driven by launch vehicle mass and volume constraints. In the late 1970 s, at the start of Hubble development, the state of the art in ground based telescopes was 3 to 4 meter monolithic primary mirrors with masses of 6000 to 10,000 kg - clearly too massive for the planned space shuttle 25,000 kg capability to LEO. Necessity led Hubble to a different solution. Launch vehicle mass constraints (and cost) resulted in the development of a 2.4 meter lightweight eggcrate mirror. At 810 kg (180 kg/m2), this mirror was approximately 7.4% of HST s total 11,110 kg mass. And, the total observatory structure at 4.3 m x 13.2 m fit snuggly inside the space shuttle 4.6 m x 18.3 m payload bay. In the early 1990 s, at the start of JWST development, the state of the art in ground based telescopes was 8 meter class monolithic primary mirrors (16,000 to 23,000 kg) and 10 meter segmented mirrors (14,400 kg). Unfortunately, launch vehicles were still constrained to 4.5 meter payloads and 25,000 kg to LEO or 6,600 kg to L2. Furthermore, science now demanded a space telescope with 6 to 8 meter aperture operating at L2. Mirror technology was identified as a critical capability necessary to enable the next generation of large aperture space telescopes. Specific telescope architectures were explored via three independent design concept studies conducted during the summer of 1996 (1). These studies identified two significant architectural constraints: segmentation and areal density. Because the launch vehicle fairing payload dynamic envelop diameter is approximately 4.5 meters, the only way to launch an 8 meter class mirror is to segment it, fold it and deploy it on orbit - resulting in actuation and control requirements. And, because of launch vehicle mass limits, the primary mirror allocation was only 1000 kg - resulting in a maximum areal density of 20 kg/m2. At the inception of

  2. Effects of fining on phenolic compounds and colour of red wine obtained with addition of increased amounts of grape solid phase in pomace

    Directory of Open Access Journals (Sweden)

    Puškaš Vladimir S.

    2012-01-01

    Full Text Available The purpose of this work is to study the effect of grape pomace enrichment in solid phase (stems and seeds on phenolic compounds and colour stability of obtained red wines, before and after use of different fining agents. Results have shown increase in total phenols and flavan-3-ols content after grape solid phase addition. On the other hand, decrease in anthocyanins content has generally been recorded in all wine samples except in wines obtained with addition of 40 g/l of seeds during maceration. Stems addition caused decrease in colour intensity while addition of seeds has increased this colour parameter. The use of four fining agents (albumin, gelatine, bentonite and PVPP has been investigated and compared, especially in terms of their influence on potential stabilization effect of grape solid phase on wine colour. Fined wines tended to have considerably lower anthocyanin and flavan-3-ol levels, especially in the case of gelatine and PVPP treatment (decrease up to 60 and 70%, respectively. In the case of chromatic parameters, used fining agents caused colour intensity decrease but it is important to emphasize that their values, after fining, are still as high as expected from red wine. This can be explained by the stabilization effect of increased flavan-3-ols content.

  3. A 4K x 4K HgCdTe astronomical camera enabled by the JWST NIR detector development program

    Science.gov (United States)

    Hall, Donald N. B.; Luppino, Gerard; Hodapp, Klaus W.; Garnett, James D.; Loose, Markus; Zandian, Majid

    2004-09-01

    The ambitious science goals of the James Webb Space Telescope (JWST) have driven spectacular advances in λco ~ 5um detector technology over the past five years. This paper reviews both the UH/RSC team"s Phase A development and evaluation of 2Kx2K arrays exceeding the detector requirements for JWST"s near infrared instruments and also the hardware integration of these into a 4Kx4K (16Mpxl) close packed mosaic focal plane array housed in an Ultra Low Background test facility. Both individual first generation 2Kx2K SCA"s and 4Kx4K mosaic focal planes have been extensively characterized in the laboratory and, since September 2003, a NIR camera utilizing the 4Kx4K mosaic focal plane has been in use for nearly 100 nights at the UH 2.2 m telescope on Mauna Kea. Typical test results for the first generation 2Kx2K arrays and their integration into 4Kx4K mosaic focal planes are reported. Demonstration of the design concepts and both array and mosaic focal plane performance in actual hardware, as described here, has provided the foundation for design iterations leading to later generations of 2Kx2K arrays and 4Kx4K mosaic focal planes. Four major technology developments leading to first generation hardware demonstrations of both 2Kx2K SCA"s and a 4Kx4K mosaic FPA are reviewed. These are: 1) improvement in test equipment and procedures to characterize the detectors against JWST requirements and goals, primarily at 37K but with the capability to test from 30K to 100K; 2) optimization of λc ~ 5 um MBE HgCdTe material on a CZT substrate for low dark current (goal of 0.003 e-/sec at 37K) with high quantum efficiency, low cross-talk and greatly reduced image persistence; 3) development of the 2Kx2K HAWAII-2RG multiplexer designed specifically to take full advantage of these detector characteristics for a wide range of astronomical applications (and fully compatible with an ASIC controller developed under the JWST Instrument Technology Development initiative) and 4) development of

  4. Studying the spectral properties of Active Galactic Nuclei in the JWST era

    CERN Document Server

    Nakos, Th; Alonso-Herrero, A; Labiano, A

    2009-01-01

    The James Webb Space Telescope (JWST), due to launch in 2014, shall provide an unprecedented wealth of information in the near and mid-infrared wavelengths, thanks to its high-sensitivity instruments and its 6.5 m primary mirror, the largest ever launched into space. NIRSpec and MIRI, the two spectrographs onboard JWST, will play a key role in the study of the spectral features of Active Galactic Nuclei in the 0.6-28 micron wavelength range. This talk aims at presenting an overview of the possibilities provided by these two instruments, in order to prepare the astronomical community for the JWST era.

  5. Classification mechanism of the chute, a liquid-phase remover of fines in the micrometre range from a batch of porous particles

    NARCIS (Netherlands)

    Jonker, G.H.; Hoffmann, A.C; Beenackers, A.A C M

    1997-01-01

    A simple and effective classification method, the 'chute', has been developed for the liquid-phase removal of fines from a batch of porous (catalyst) particles in the micrometre range. The chute is a continuous sedimentation fractionator, working in the gravitational field. Equations based an the se

  6. Extrasolar Planets Observed with JWST and the ELTs

    Science.gov (United States)

    Deming, L. Drake

    2010-01-01

    The advent of cryogenic space-borne infrared observatories such as the Spitzer Space Telescope has lead to a revolution in the study of planets and planetary systems orbiting sun-like stars. Already Spitzer has characterized the emergent infrared spectra of close-in giant exoplanets using transit and eclipse techniques. The James Webb Space Telescope (JWST) will be able to extend these studies to superEarth exoplanets orbiting in the habitable zones of M-dwarf stars in the near solar neighborhood. The forthcoming ground-based Extremely Large Telescopes (ELTs) will playa key role in these studies, being especially valuable for spectroscopy at higher spectral resolving powers where large photon fluxes are needed. The culmination of this work within the next two decades will be the detection and spectral characterization of the major molecular constituents in the atmosphere of a habitable superEarth orbiting a nearby lower main sequence star.

  7. Augmented Method to Improve Thermal Data for the Figure Drift Thermal Distortion Predictions of the JWST OTIS Cryogenic Vacuum Test

    Science.gov (United States)

    Park, Sang C.; Carnahan, Timothy M.; Cohen, Lester M.; Congedo, Cherie B.; Eisenhower, Michael J.; Ousley, Wes; Weaver, Andrew; Yang, Kan

    2017-01-01

    The JWST Optical Telescope Element (OTE) assembly is the largest optically stable infrared-optimized telescope currently being manufactured and assembled, and is scheduled for launch in 2018. The JWST OTE, including the 18 segment primary mirror, secondary mirror, and the Aft Optics Subsystem (AOS) are designed to be passively cooled and operate near 45K. These optical elements are supported by a complex composite backplane structure. As a part of the structural distortion model validation efforts, a series of tests are planned during the cryogenic vacuum test of the fully integrated flight hardware at NASA JSC Chamber A. The successful ends to the thermal-distortion phases are heavily dependent on the accurate temperature knowledge of the OTE structural members. However, the current temperature sensor allocations during the cryo-vac test may not have sufficient fidelity to provide accurate knowledge of the temperature distributions within the composite structure. A method based on an inverse distance relationship among the sensors and thermal model nodes was developed to improve the thermal data provided for the nanometer scale WaveFront Error (WFE) predictions. The Linear Distance Weighted Interpolation (LDWI) method was developed to augment the thermal model predictions based on the sparse sensor information. This paper will encompass the development of the LDWI method using the test data from the earlier pathfinder cryo-vac tests, and the results of the notional and as tested WFE predictions from the structural finite element model cases to characterize the accuracies of this LDWI method.

  8. Two NIRCam channels are Better than One: How JWST Can Do More Science with NIRCam's Short-Wavelength Dispersed Hartmann Sensor

    CERN Document Server

    Schlawin, Everett; Leisenring, Jarron; Greene, Tom; Walker, Lisa May; Fraine, Jonathan; Kelly, Doug; Misselt, Karl; Line, Michael; Stansberry, John; Lewis, Nikole

    2016-01-01

    The James Webb Space Telescope (JWST) offers unprecedented sensitivity, stability, and wavelength coverage for transiting exoplanet studies, opening up new avenues for measuring atmospheric abundances, structure, and temperature profiles. Taking full advantage of JWST spectroscopy of planets from 0.6um to 28um, however, will require many observations with a combination of the NIRISS, NIRCam, NIRSpec, and MIRI instruments. In this white paper, we discuss a new NIRCam mode (not yet approved or implemented) that can reduce the number of necessary observations to cover the 1.0um to 5.0um wavelength range. Even though NIRCam was designed primarily as an imager, it also includes several grisms for phasing and aligning JWST's 18 hexagonal mirror segments. NIRCam's long-wavelength channel includes grisms that cover 2.4um to 5.0um with a resolving power of R = 1200 - 1550 using two separate configurations. The long-wavelength grisms have already been approved for science operations, including wide field and single obj...

  9. Two NIRCam Channels are Better than One: How JWST Can Do More Science with NIRCam’s Short-wavelength Dispersed Hartmann Sensor

    Science.gov (United States)

    Schlawin, E.; Rieke, M.; Leisenring, J.; Walker, L. M.; Fraine, J.; Kelly, D.; Misselt, K.; Greene, T.; Line, M.; Lewis, N.; Stansberry, J.

    2017-01-01

    The James Webb Space Telescope (JWST) offers unprecedented sensitivity, stability, and wavelength coverage for transiting exoplanet studies, opening up new avenues for measuring atmospheric abundances, structure, and temperature profiles. Taking full advantage of JWST spectroscopy of planets from 0.6 to 28 μm, however, will require many observations with a combination of the NIRISS, NIRCam, NIRSpec, and MIRI instruments. In this white paper, we discuss a new NIRCam mode (not yet approved or implemented) that can reduce the number of necessary observations to cover the 1.0-5.0 μm wavelength range. Even though NIRCam was designed primarily as an imager, it also includes several grisms for phasing and aligning JWST’s 18 hexagonal mirror segments. NIRCam’s long-wavelength channel includes grisms that cover 2.4-5.0 μm with a resolving power of R = 1200-1550 using two separate configurations. The long-wavelength grisms have already been approved for science operations, including wide field and single object (time series) slitless spectroscopy. We propose a new mode that will simultaneously measure spectra for science targets in the 1.0-2.0 μm range using NIRCam’s short-wavelength channel. This mode, if approved, would take advantage of NIRCam’s Dispersed Hartmann Sensor (DHS), which produces 10 spatially separated spectra per source at R ˜ 300. We discuss the added benefit of the DHS in constraining abundances in exoplanet atmospheres as well as its ability to observe the brightest systems. The DHS essentially comes for free (at no time cost) with any NIRCam long-wavelength grism observation, but the detector integration parameters have to be selected to ensure that the long-wavelength grism observations do not saturate and that JWST data volume downlink constraints are not violated. Combining both of NIRCam’s channels will maximize the science potential of JWST, which is a limited life observatory.

  10. Observing Outer Planet Satellites (except Titan) with JWST: Science Justification and Observational Requirements

    CERN Document Server

    Keszthelyi, Laszlo; Stansberry, John; Sivaramakrishnan, Anand; Thatte, Deepashri; Gudipati, Murthy; Tsang, Constantine; Greenbaum, Alexandra; McGruder, Chima

    2015-01-01

    The James Webb Space Telescope (JWST) will allow observations with a unique combination of spectral, spatial, and temporal resolution for the study of outer planet satellites within our Solar System. We highlight the infrared spectroscopy of icy moons and temporal changes on geologically active satellites as two particularly valuable avenues of scientific inquiry. While some care must be taken to avoid saturation issues, JWST has observation modes that should provide excellent infrared data for such studies.

  11. Observing outer planet satellites (except Titan) with JWST: Science justification and observational requirements

    Science.gov (United States)

    Kestay, Laszlo P.; Grundy, Will; Stansberry, John; Sivaramakrishnan, Anand; Thatte, Deepashri; Gudipati, Murthy; Tsang, Constantine; Greenbaum, Alexandra; McGruder, Chima

    2016-01-01

    The James Webb Space Telescope (JWST) will allow observations with a unique combination of spectral, spatial, and temporal resolution for the study of outer planet satellites within our Solar System. We highlight the infrared spectroscopy of icy moons and temporal changes on geologically active satellites as two particularly valuable avenues of scientific inquiry. While some care must be taken to avoid saturation issues, JWST has observation modes that should provide excellent infrared data for such studies.

  12. Laves-phase evolution during aging in fine grained heat-affected zone of a tungsten-strengthened 9% Cr steel weldment

    OpenAIRE

    Wang, Xue; XU, Qiang; Yu, Shu-min; Liu, Hong; Hu, Lei; Ren, Yao-yao

    2015-01-01

    The precipitation and coarsening of Laves-phase in the fine grained heat-affected zone (FGHAZ) of a 9% Cr steel P92 welded joint during thermal aging at 923 K were investigated and compared to the base metal (BM), in order to clarify their effects on the Type IV fracture. Laves-phase precipitated mostly on the prior austenite grain boundaries of the FGHAZ. In comparison with BM, FGHAZ contained more grain boundary areas and can provide more nucleation sites for Laves-phase, resulting in an ac...

  13. Exploring JWST's Capability to Constrain Habitability on Simulated Terrestrial TESS Planets

    Science.gov (United States)

    Tremblay, Luke; Britt, Amber; Batalha, Natasha; Schwieterman, Edward; Arney, Giada; Domagal-Goldman, Shawn; Mandell, Avi; Planetary Systems Laboratory; Virtual Planetary Laboratory

    2017-01-01

    In the following, we have worked to develop a flexible "observability" scale of biologically relevant molecules in the atmospheres of newly discovered exoplanets for the instruments aboard NASA's next flagship mission, the James Webb Space Telescope (JWST). We sought to create such a scale in order to provide the community with a tool with which to optimize target selection for JWST observations based on detections of the upcoming Transiting Exoplanet Satellite Survey (TESS). Current literature has laid the groundwork for defining both biologically relevant molecules as well as what characteristics would make a new world "habitable", but it has so far lacked a cohesive analysis of JWST's capabilities to observe these molecules in exoplanet atmospheres and thereby constrain habitability. In developing our Observability Scale, we utilized a range of hypothetical planets (over planetary radii and stellar insolation) and generated three self-consistent atmospheric models (of dierent molecular compositions) for each of our simulated planets. With these planets and their corresponding atmospheres, we utilized the most accurate JWST instrument simulator, created specically to process transiting exoplanet spectra. Through careful analysis of these simulated outputs, we were able to determine the relevant parameters that effected JWST's ability to constrain each individual molecular bands with statistical accuracy and therefore generate a scale based on those key parameters. As a preliminary test of our Observability Scale, we have also applied it to the list of TESS candidate stars in order to determine JWST's observational capabilities for any soon-to-be-detected planet in those solar systems.

  14. JWST Near-Infrared Detector Degradation: Finding the Problem, Fixing the Problem, and Moving Forward

    Science.gov (United States)

    Rauscher, Bernard J.; Stahle, Carl; Hill, Bob; Greenhouse, Matt; Beletic, James; Babu, Sachidananda; Blake, Peter; Cleveland, Keith; Cofie, Emmanuel; Eegholm, Bente; Engelbracht, Chad; Hall, Don; Hoffman, Alan; Jeffers, Basil; Jhabvala, Christine; Kimble, Randy; Kopp, Robert; Lee, Don; Leidecker, Henning; Lindler, Don; McMurray, Bob; Mott, D. Brent; Ohl, Ray; Polis, Don; Pontius, Jim

    2012-01-01

    The James Webb Space Telescope (JWST) is the successor to the Hubble Space Telescope. JWST will be an infrared optimized telescope, with an approximately 6.5 m diameter primary mirror, that is located at the Sun-Earth L2 Lagrange point. Three of JWST's four science instruments use Teledyne HgCdTe HAWAII-2RG (H2RG) near infrared detector arrays. During 2010, the JWST Project noticed that a few of its 5 micron cutoff H2RG detectors were degrading during room temperature storage, and NASA chartered a "Detector Degradation Failure Review Board" (DD-FRB) to investigate. The DD-FRB determined that the root cause was a design flaw that allowed indium to interdiffuse with the gold contacts and migrate into the HgCdTe detector layer. Fortunately, Teledyne already had an improved design that eliminated this degradation mechanism. During early 2012, the improved H2RG design was qualified for flight and JWST began making additional H2RGs. In this article we present the two public DD-FRB "Executiye Summaries" that: (1) determined the root cause of the detector degradation and (2) defined tests to determine whether the existing detectors are qualified for flight. We supplement these with a brief introduction to H2RG detector arrays, and a discussion of how the JWST Project is using cryogenic storage to retard the degradation rate of the existing flight spare H2RGs.

  15. Deep IRAC Imaging Lensing Galaxy Clusters for JWST 'First Light' Search

    Science.gov (United States)

    Yan, Haojing; Conselice, Christopher; Windhorst, Rogier; Cohen, Seth; Alpaslan, Mehmet; Zitrin, Adi; Broadhurst, Tom; Frye, Brenda; Driver, Simon; Robotham, Aaron; Hopkins, Andrew; Wyithe, Staurt; Jansen, Rolf; Hathi, Nimish; Mechtley, Matthew; Ryan, Russell; Rutkowski, Michael; Finkelstein, Steven; Koekemoer, Anton

    2016-08-01

    JWST has a key goal to search for First Light objects beyond z>10. Our 110-hr JWST GTO program, 'Webb Medium-Deep Fields' (WMDF), will target both blank and lensed fields to probe both the bright and the faint ends of the galaxy luminosity function at z > 10. While a number of well studied lensing clusters exist, not all of them are optimal for the JWST search of First Light objects, either because of their low Ecliptic latitudes (and hence high Zodiacal background) or because of their strong intra-cluster light (ICL) at the critical curve regions corresponding to the redshifts of interest. For this reason, our WMDF candidate lensing targets will include some recently discovered, high-mass (log[M/Msun] ~ 15) galaxy clusters, which we choose either because of their high Ecliptic latitude (beta > 40 deg) or because of their extreme compactness that minimizes the impact of the ICL. As part of our effort to collect ancillary data for these new systems to finalize the target list, we propose IRAC observations for 13 of them that are lacking sufficient data. These 3.6/4.5um data will be critical for our guaranteed JWST program: (1) they will greatly facilitate the modeling of the straylight that JWST will suffer in 1--5 um (the key range to search for z>10--20 objects), a problem that has recently been identified. If left untreated, such straylight components would severely hamper the detection of faint sources in a lensing field. The JWST observations alone would be difficult to separate the ICL from the straylight at the level needed. (2) the new 3.6/4.5um data will best match our deep optical imaging and spectroscopy at HST, Gemini, LBT and MMT. We will derive accurate photometric redshifts for any lensed background galaxies (at znote that these data will be highly valuable for the study of these clusters themselves before the JWST mission.

  16. Bayesian Approach for Reliability Assessment of Sunshield Deployment on JWST

    Science.gov (United States)

    Kaminskiy, Mark P.; Evans, John W.; Gallo, Luis D.

    2013-01-01

    Deployable subsystems are essential to mission success of most spacecraft. These subsystems enable critical functions including power, communications and thermal control. The loss of any of these functions will generally result in loss of the mission. These subsystems and their components often consist of unique designs and applications, for which various standardized data sources are not applicable for estimating reliability and for assessing risks. In this study, a Bayesian approach for reliability estimation of spacecraft deployment was developed for this purpose. This approach was then applied to the James Webb Space Telescope (JWST) Sunshield subsystem, a unique design intended for thermal control of the observatory's telescope and science instruments. In order to collect the prior information on deployable systems, detailed studies of "heritage information", were conducted extending over 45 years of spacecraft launches. The NASA Goddard Space Flight Center (GSFC) Spacecraft Operational Anomaly and Reporting System (SOARS) data were then used to estimate the parameters of the conjugative beta prior distribution for anomaly and failure occurrence, as the most consistent set of available data and that could be matched to launch histories. This allows for an emperical Bayesian prediction for the risk of an anomaly occurrence of the complex Sunshield deployment, with credibility limits, using prior deployment data and test information.

  17. Predicting the High Redshift Galaxy Population for JWST

    Science.gov (United States)

    Flynn, Zoey; Benson, Andrew

    2017-01-01

    The James Webb Space Telescope will be launched in Oct 2018 with the goal of observing galaxies in the redshift range of z = 10 - 15. As redshift increases, the age of the Universe decreases, allowing us to study objects formed only a few hundred million years after the Big Bang. This will provide a valuable opportunity to test and improve current galaxy formation theory by comparing predictions for mass, luminosity, and number density to the observed data. We have made testable predictions with the semi-analytical galaxy formation model Galacticus. The code uses Markov Chain Monte Carlo methods to determine viable sets of model parameters that match current astronomical data. The resulting constrained model was then set to match the specifications of the JWST Ultra Deep Field Imaging Survey. Predictions utilizing up to 100 viable parameter sets were calculated, allowing us to assess the uncertainty in current theoretical expectations. We predict that the planned UDF will be able to observe a significant number of objects past redshift z > 9 but nothing at redshift z > 11. In order to detect these faint objects at redshifts z = 11-15 we need to increase exposure time by at least a factor of 1.66.

  18. Community Targets for JWST's Early Release Science Program: Evaluation of Transiting Exoplanet WASP-63b.

    Science.gov (United States)

    Kilpatrick, Brian; Cubillos, Patricio; Bruno, Giovanni; Lewis, Nikole K.; Stevenson, Kevin B.; Wakeford, Hannah; Blecic, Jasmina; Burrows, Adam Seth; Deming, Drake; Heng, Kevin; Line, Michael R.; Madhusudhan, Nikku; Morley, Caroline; Waldmann, Ingo P.; Transiting Exoplanet Early Release Science Community (Stevenson et al. 2016)

    2017-06-01

    We present observations of the Hubble Space Telescope (HST) ``A Preparatory Program to Identify the Single Best Transiting Exoplanet for JWST Early Release Science" for WASP-63b, one of the community targets proposed for the James Webb Space Telescope (JWST) Early Release Science (ERS) program. A large collaboration of transiting exoplanet scientists identified a set of ``community targets" which meet a certain set of criteria for ecliptic latitude, period, host star brightness, well constrained orbital parameters, and strength of spectroscopic features. WASP-63b was one of the targets identified as a potential candidate for the ERS program. It is presented as an inflated planet with a large signal. It will be accessible to JWST approximately six months after the planned start of Cycle 1/ERS in April 2019 making it an ideal candidate should there be any delays in the JWST timetable. Here, we observe WASP-63b to evaluate its suitability as the best target to test the capabilities of JWST. Ideally, a clear atmosphere will be best suited for bench marking the instruments ability to detect spectroscopic features. We can use the strength of the water absorption feature at 1.4 μm as a way to determine the presence of obscuring clouds/hazes. The results of atmospheric retrieval are presented along with a discussion on the suitability of WASP-63b as the best target to be observed during the ERS Program.

  19. Phase stability and grain growth in an Ag/Bi-2223 composite conductor prepared using fine-grained Bi-2223 as a precursor.

    Energy Technology Data Exchange (ETDEWEB)

    Merchant, N. N.

    1998-09-17

    We have investigated the stability and microstructural transformability of the Bi-2223 phase in a silver-sheathed monofilament composite tape fabricated using fine-grained Bi{sub 1.7}Pb{sub 0.3}Sr{sub 1.9}Ca{sub 2.0}-Cu{sub 3.0}O{sub y} (Bi-2223) as the precursor powder. The fully formed Bi-2223 precursor was prepared using established procedures. The purpose of this study was to explore the prospects for growing textured, large-grain-size Bi-2223 from the fine-grained precursor by process parameter perturbations. These perturbations included thermal ramp up variations, programmed heat treatment temperature and oxygen pressure fluctuations, and parameter manipulations during cool-down. Our results show that the types of heat treatments used in conventional oxide-powder-in-tube (OPIT) processing do not facilitate Bi-2223 grain growth when the precursor powder is preconcerted Bi-2223. We also observed that the Bi-2223 partially. decomposed during conventional thermal ramp-up in 0.075 atm O{sub 2}, but that this decomposition can be inhibited by ramping up in a reduced oxygen pressure. A pathway was found for back-reacting the fine-grained Bi-2223 (to Bi-2212, Bi-2201 and nonsuperconducting secondary phases), then reforming large-grained Bi-2223 in a colony microstructure having some distinct differences from that produced during conventional OPIT processing.

  20. First phase monitoring studies of simulated benthic disturbance delineating movement of fine particles in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.

    . The travel effects of INDEX plume appears to be localized and confined within and around the disturbed zone (DZ) as resettlement of fine particles from the benthic plume was traced up to 2 km south and 12 to 18 km north of the DZ. The evidence does...

  1. From the Big Bang to the Nobel Prize and the JWST

    Science.gov (United States)

    Mather, John C.

    2007-01-01

    I will describe the history of the universe, from the Big Bang to 2013, when the JWST is to be launched to look back towards our beginnings. I will discuss how the COBE results led to the Nobel Prize, how the COBE results have been confirmed and extended, and their implications for future observations. The James Webb Space Telescope will be used to examine every part of our history from the first stars and galaxies to the formation of individual stars and planets and the delivery of life-supporting materials to the Earth. I will describe the plans for the JWST and how observers may use it. With luck, the JWST may produce a Nobel Prize for some discovery we can only guess today.

  2. Cryo-vacuum testing of the JWST Integrated Science Instrument Module (SPIE)

    Science.gov (United States)

    Kimble, Randy A.; Vila, M. Begona; Van Campen, Julie; Birkmann, Stephan M.; Comber, Brian J.; Fatig, Curtis C.; Glasse, Alistair C. H.; Glazer, Stuart D.; Kelly, Douglas M.; Mann, Steven D.; Martel, Andre R.; Novo-Gradac, Kevin J.; Ohl, Raymond G.; Penanen, Konstantin; Rohrbach, Scott O.; Sullivan, Joseph F.; Zak, Dean; Zhou, Julia

    2016-01-01

    In late 2015/early 2016, a major cryo-vacuum test was carried out for the Integrated Science Instrument Module (ISIM) of the James Webb Space Telescope (JWST). This test comprised the final cryo-certification and calibration test of the ISIM, after its ambient environmental test program (vibration, acoustics, EMI/EMC), and before its delivery for integration with the rest of the JWST observatory. Over the 108-day period of the round-the-clock test program, the full complement of ISIM flight instruments, structure, harness radiator, and electronics were put through a comprehensive program of thermal, optical, electrical, and operational tests. The test verified the health and excellent performance of the instruments and ISIM systems, proving the ISIM element's readiness for integration with the telescope. We report here on the context, goals, setup, execution, and key results for this critical JWST milestone.

  3. Emulating JWST Exoplanet Transit Observations in a Testbed laboratory experiment

    Science.gov (United States)

    Touli, D.; Beichman, C. A.; Vasisht, G.; Smith, R.; Krist, J. E.

    2014-12-01

    The transit technique is used for the detection and characterization of exoplanets. The combination of transit and radial velocity (RV) measurements gives information about a planet's radius and mass, respectively, leading to an estimate of the planet's density (Borucki et al. 2011) and therefore to its composition and evolutionary history. Transit spectroscopy can provide information on atmospheric composition and structure (Fortney et al. 2013). Spectroscopic observations of individual planets have revealed atomic and molecular species such as H2O, CO2 and CH4 in atmospheres of planets orbiting bright stars, e.g. Deming et al. (2013). The transit observations require extremely precise photometry. For instance, Jupiter transit results to a 1% brightness decrease of a solar type star while the Earth causes only a 0.0084% decrease (84 ppm). Spectroscopic measurements require still greater precision ppm. The Precision Projector Laboratory (PPL) is a collaboration between the Jet Propulsion Laboratory (JPL) and California Institute of Technology (Caltech) to characterize and validate detectors through emulation of science images. At PPL we have developed a testbed to project simulated spectra and other images onto a HgCdTe array in order to assess precision photometry for transits, weak lensing etc. for Explorer concepts like JWST, WFIRST, EUCLID. In our controlled laboratory experiment, the goal is to demonstrate ability to extract weak transit spectra as expected for NIRCam, NIRIS and NIRSpec. Two lamps of variable intensity, along with spectral line and photometric simulation masks emulate the signals from a star-only, from a planet-only and finally, from a combination of a planet + star. Three masks have been used to simulate spectra in monochromatic light. These masks, which are fabricated at JPL, have a length of 1000 pixels and widths of 2 pixels, 10 pixels and 1 pixel to correspond respectively to the noted above JWST instruments. From many-hour long observing

  4. JWST NIRCam WFSS Ice Feature Spectroscopy in Nearby Molecular Cores

    Science.gov (United States)

    Chu, Laurie; Hodapp, Klaus W.; Rieke, Marcia J.; Meyer, Michael; Greene, Thomas P.; JWST NIRCam Science Team

    2017-06-01

    In molecular clouds above a few magnitudes of total visual extinction, some components of the molecular gas freeze out on the surfaces of dust grains. These ice mantles around dust grains are the site of complex surface chemistry that leads to the formation of simple organic molecules in these mantles. The icy surfaces also facilitate the coaggulation of the dust particles, setting the stage for grain growth and ultimately the formation of planetary bodies.As part of the JWST NIRCam GTO program, we plan to observe a selection of small molecular cores using the wide field grism spectroscopy mode of NIRCam.This poster presents the results of a preliminary study of several candidate molecular cores using UKIRT, Spitzer IRAC, IRTF SpeX, Keck MOSFIRE and Subaru MOIRCS data.After the prelimary studies we have selected three molecular cores in different evolutionary stages for the GTO program: B68, a quiescent molecular core, LDN 694-2, a collapsing pre-stellar core, and B335, a protostellar core. All these cores are seen against a dense background of stars in the inner Galaxy and offer the opportunity for spatially well resolved mapping of the ice feature distribution. We will obtain slitless grism spectroscopy in six filters covering the features of H2O, CO2, CO, CH3OH, and the XCN feature. Simulations using aXeSIM have shown that spectrum overlap will occur in a fraction of the spectra, but will not be a prohibitive problem.Our poster will discuss the details of observations planned out in the APT system.

  5. Astrochemistry with the Mid-InfraRed Instrument on JWST

    Science.gov (United States)

    van Dishoeck, E. F.; Merín, B.; Brandl, B.; Böker, T.; Greene, T.; Meixner, M.; Ressler, M.; Rieke, G.; Waelkens, C.; Wright, G.; Miri Team

    JWST-MIRI will have imaging and medium resolution (λ/Δλ ≍ 2000-3000) integral field spectroscopy with orders of magnitude improvements in sensitivity and/or spatial resolution compared with existing facilities. It will be a prime facility for astrochemical studies of gases and solids in a wide variety of objects in the next decade. 1. Introduction Mid-infrared spectroscopy is becoming a powerful tool in astrochemistry, with studies of molecules and sources that are highly complementary to those at millimeter wavelengths. Molecules without permanent dipole moments such CH4, C2H2 and CO2 can only be observed through their vibration-rotation transitions. Space-based missions open up the possibility to study molecules which are abundant in ouw own atmosphere, in particular H2O. Polycyclic Aromatic Hydrocarbons have their most prominent features at mid-infrared wavelengths, and the pure rotational transitions of the dominant molecule in the universe, H2, also occur in this band. Solid-state material is uniquely probed in the mid-infrared, including characteric bands of ices, silicates, oxides, carbides, carbonates and sulfides. The wealth of mid-infrared spectroscopy has been demonstrated by results from the ISO satellite (see van Dishoeck & Tielens 2001, van Dishoeck 2004 for reviews), by pioneering ground-based studies (Lacy et al. 1989, Evans et al. 1990) and most recently by the Spitzer Space Telescope. Targets include molecular clouds, PDRs, shocks, deeply embedded young stellar objects, UC HII regions, protoplanetary disks, planetary atmospheres, comets, evolved stars and even entire galaxies. In addition to an inventory of gaseous and solid-state material, the lines and line ratios provide powerful diagnostics of temperatures, densities, UV field, elemental abundances, etc. Systematic variations in features from region to region allow the physical and chemical processes to be traced. The MidInfraRed Instrument (MIRI) on board the 6m James Webb Space

  6. Commentary: JWST near-infrared detector degradation— finding the problem, fixing the problem, and moving forward

    Directory of Open Access Journals (Sweden)

    Bernard J. Rauscher

    2012-06-01

    Full Text Available The James Webb Space Telescope (JWST is the successor to the Hubble Space Telescope. JWST will be an infrared-optimized telescope, with an approximately 6.5 m diameter primary mirror, that is located at the Sun-Earth L2 Lagrange point. Three of JWST’s four science instruments use Teledyne HgCdTe HAWAII-2RG (H2RG near infrared detector arrays. During 2010, the JWST Project noticed that a few of its 5 μm cutoff H2RG detectors were degrading during room temperature storage, and NASA chartered a “Detector Degradation Failure Review Board” (DD-FRB to investigate. The DD-FRB determined that the root cause was a design flaw that allowed indium to interdiffuse with the gold contacts and migrate into the HgCdTe detector layer. Fortunately, Teledyne already had an improved design that eliminated this degradation mechanism. During early 2012, the improved H2RG design was qualified for flight and JWST began making additional H2RGs. In this article, we present the two public DD-FRB “Executive Summaries” that: (1 determined the root cause of the detector degradation and (2 defined tests to determine whether the existing detectors are qualified for flight. We supplement these with a brief introduction to H2RG detector arrays, some recent measurements showing that the performance of the improved design meets JWST requirements, and a discussion of how the JWST Project is using cryogenic storage to retard the degradation rate of the existing flight spare H2RGs.

  7. Prospects for Habitable World Detections Using James Webb Space Telescope (JWST)

    Science.gov (United States)

    Deming, Drake

    2010-01-01

    Doppler and transit surveys are finding extrasolar planets of ever smaller mass and radius, and are now sampling the domain of superEarths. Recent results from the Doppler surveys suggest that discovery of a transiting superEarth in the habitable zone of a lower main sequence star may be possible. We evaluate the prospects for an all-sky transit survey targeted to the brightest stars I that would find the most favorable cases for photometric and spectroscopic characterization using the James Webb Space Telescope. We use the proposed Transiting Exoplanet Survey Satellite (TESS) as representative of an all-sky survey. We couple the simulated TESS yield to a sensitivity model for the MIRI and NIRSpec instruments on JWST. Our sensitivity model includes all currently known and anticipated sources of random and systematic error for these instruments. We focus on the TESS planets with radii between Earth and Neptune. Our simulations consider secondary eclipse filter photometry using JWST/MIRI, comparing the 11- and 15- micron bands to measure carbon dioxide absorption in superEarths, as well as JWST!NIRSpec spectroscopy of water absorption from 1.7-3.0 microns, and carbon dioxide absorption at 4.3 microns. We find that JWST will be capable of characterizing dozens of TESS superEarths with temperatures above the habitable range, using both MIRI and NIRspec. We project that TESS will discover about eight nearby habitable transiting superEarths, all orbiting lower main sequence stars. The principal sources of uncertainty in the prospects for JWST characterization of habitable superEarths are superEarth frequency and the nature of superEarth atmospheres. Based on our estimates of these uncertainties, we project that JWST will be able to measure the temperature, and identify molecular absorptions (water, carbon dioxide) in one to four nearby habitable TESS superEarths orbiting lower main sequence stars.

  8. The JWST North Ecliptic Pole Survey Field for Time-domain Studies

    Science.gov (United States)

    Jansen, Rolf A.; Alpaslan, Mehmet; Ashby, Matthew; Ashcraft, Teresa; Cohen, Seth H.; Condon, James J.; Conselice, Christopher; Ferrara, Andrea; Frye, Brenda L.; Grogin, Norman A.; Hammel, Heidi B.; Hathi, Nimish P.; Joshi, Bhavin; Kim, Duho; Koekemoer, Anton M.; Mechtley, Matt; Milam, Stefanie N.; Rodney, Steven A.; Rutkowski, Michael J.; Strolger, Louis-Gregory; Trujillo, Chadwick A.; Willmer, Christopher; Windhorst, Rogier A.; Yan, Haojing

    2017-01-01

    The JWST North Ecliptic Pole (NEP) Survey field is located within JWST's northern Continuous Viewing Zone, will span ˜14‧ in diameter (˜10‧ with NIRISS coverage) and will be roughly circular in shape (initially sampled during Cycle 1 at 4 distinct orientations with JWST/NIRCam's 4.4‧×2.2‧ FoV —the JWST “windmill”) and will have NIRISS slitless grism spectroscopy taken in parallel, overlapping an alternate NIRCam orientation. This is the only region in the sky where JWST can observe a clean extragalactic deep survey field (free of bright foreground stars and with low Galactic foreground extinction AV) at arbitrary cadence or at arbitrary orientation. This will crucially enable a wide range of new and exciting time-domain science, including high redshift transient searches and monitoring (e.g., SNe), variability studies from Active Galactic Nuclei to brown dwarf atmospheres, as well as proper motions of extreme scattered Kuiper Belt and Oort Cloud Objects, and of nearby Galactic brown dwarfs, low-mass stars, and ultracool white dwarfs. We therefore welcome and encourage follow-up through GO programs of the initial GTO observations to realize its potential as a JWST time-domain community field. The JWST NEP Survey field was selected from an analysis of WISE 3.4+4.6 micron, 2MASS JHKs, and SDSS ugriz source counts and of Galactic foreground extinction, and is one of very few such ˜10‧ fields that are devoid of sources brighter than mAB = 16 mag. We have secured deep (mAB ˜ 26 mag) wide-field (˜23‧×25‧) Ugrz images of this field and its surroundings with LBT/LBC. We also expect that deep MMT/MMIRS YJHK images, deep 8-12 GHz VLA radio observations (pending), and possibly HST ACS/WFC and WFC3/UVIS ultraviolet-visible images will be available before JWST launches in Oct 2018.

  9. Habitable worlds with JWST: transit spectroscopy of the TRAPPIST-1 system?

    Science.gov (United States)

    Barstow, J. K.; Irwin, P. G. J.

    2016-09-01

    The recent discovery of three Earth-sized, potentially habitable planets around a nearby cool star, TRAPPIST-1, has provided three key targets for the upcoming James Webb Space Telescope (JWST). Depending on their atmospheric characteristics and precise orbit configurations, it is possible that any of the three planets may be in the liquid water habitable zone, meaning that they may be capable of supporting life. We find that present-day Earth levels of ozone, if present, would be detectable if JWST observes 60 transits for innermost planet 1b and 30 transits for 1c and 1d.

  10. Habitable worlds with JWST: transit spectroscopy of the TRAPPIST-1 system?

    CERN Document Server

    Barstow, Joanna K

    2016-01-01

    The recent discovery of three Earth-sized, potentially habitable planets around a nearby cool star, TRAPPIST-1, has provided three key targets for the upcoming James Webb Space Telescope (JWST). Depending on their atmospheric characteristics and precise orbit configurations, it is possible that any of the three planets may be in the liquid water habitable zone, meaning that they may be capable of supporting life. We find that present-day Earth levels of ozone, if present, would be detectable if JWST observes 60 transits for innermost planet 1b and 30 transits for 1c and 1d.

  11. Synergistic Utilization of Coal Fines and Municipal Solid Waste in Coal-Fired Boilers. Phase I Final Report

    Energy Technology Data Exchange (ETDEWEB)

    V. Zamansky; P. Maly; M. Klosky

    1998-06-12

    A feasibility study was performed on a novel concept: to synergistically utilize a blend of waste coal fines with so-called E-fuel for cofiring and reburning in utility and industrial boilers. The E-fuel is produced from MSW by the patented EnerTech's slurry carbonization process. The slurry carbonization technology economically converts MSW to a uniform, low-ash, low-sulfur, and essentially chlorine-free fuel with energy content of about 14,800 Btu/lb.

  12. Information Content Analysis for Selection of Optimal JWST Observing Modes for Transiting Exoplanet Atmospheres

    Science.gov (United States)

    Batalha, Natasha E.; Line, M. R.

    2017-04-01

    The James Webb Space Telescope (JWST) is nearing its launch date of 2018, and is expected to revolutionize our knowledge of exoplanet atmospheres. In order to specifically identify which observing modes will be most useful for characterizing a diverse range of exoplanetary atmospheres, we use an information content (IC) based approach commonly used in the studies of solar system atmospheres. We develop a system based upon these IC methods to trace the instrumental and atmospheric model phase space in order to identify which observing modes are best suited for particular classes of planets, focusing on transmission spectra. Specifically, the atmospheric parameter space we cover is T = 600-1800 K, C/O = 0.55-1, [M/H] = 1-100 × Solar for an R = 1.39 R J , M = 0.59 M J planet orbiting a WASP-62-like star. We also explore the influence of a simplified opaque gray cloud on the IC. We find that obtaining broader wavelength coverage over multiple modes is preferred over higher precision in a single mode given the same amount of observing time. Regardless of the planet temperature and composition, the best modes for constraining terminator temperatures, C/O ratios, and metallicity are NIRISS SOSS+NIRSpec G395. If the target’s host star is dim enough such that the NIRSpec prism is applicable, then it can be used instead of NIRISS SOSS+NIRSpec G395. Lastly, observations that use more than two modes should be carefully analyzed because sometimes the addition of a third mode results in no gain of information. In these cases, higher precision in the original two modes is favorable.

  13. Development and Acceptance Testing of the Dual Wheel Mechanism for the Tunable Filter Imager Cryogenic Instrument on the JWST

    Science.gov (United States)

    Leckie, Martin; Ahmad, Zakir

    2010-01-01

    The James Webb Space Telescope (JWST) will carry four scientific instruments, one of which is the Tunable Filter Imager (TFI), which is an instrument within the Fine Guidance Sensor. The Dual Wheel (DW) mechanism is being designed, built and tested by COM DEV Ltd. under contract from the Canadian Space Agency. The DW mechanism includes a pupil wheel (PW) holding seven coronagraphic masks and two calibration elements and a filter wheel (FW) holding nine blocking filters. The DW mechanism must operate at both room temperature and at 35K. Successful operation at 35K comprises positioning each optical element with the required repeatability, for several thousand occasions over the five year mission. The paper discusses the results of testing geared motors and bearings at the cryogenic temperature. In particular bearing retainer design and PGM-HT material, the effects of temperature gradients across bearings and the problems associated with cooling mechanisms down to cryogenic temperatures. The results of additional bearing tests are described that were employed to investigate an abnormally high initial torque experienced at cryogenic temperatures. The findings of these tests, was that the bearing retainer and the ball/race system could be adversely affected by the large temperature change from room temperature to cryogenic temperature and also the temperature gradient across the bearing. The DW mechanism is now performing successfully at both room temperature and at cryogenic temperature. The life testing of the mechanism is expected to be completed in the first quarter of 2010.

  14. The Molecular Universe as seen by JWST-MIRI

    Science.gov (United States)

    Lahuis, F.; van Dishoeck, E. F.; Wright, G.; Rieke, G.

    2011-05-01

    The Mid-InfraRed Instrument (MIRI, Wright et al. 2003) on board the James Webb Space Telescope (JWST) will be the next major mid-infrared facility in space. It combines a high sensitivity with medium resolution spectroscopy and subarcsec imaging. This makes it one of the prime facilities for astrochemical studies in the next decade. Mid-infrared spectroscopy is a very powerful astrochemical tool. Molecules without permanent dipoles such as CH_4, C_2H_2 and CO_2 can only be observed through their vibration-rotation transitions while atmospheric species, in particular H_2O, require space-based facilities. PAH and solid-state material have prominent features in the mid-infrared, and the pure rotational transitions of the dominant molecule in the universe, H_2, also occur in this band. The wealth of mid-infrared spectroscopy has been demonstrated by results from the ISO satellite (see van Dishoeck 2004 for a review), pioneering ground-based studies and most recently by the Spitzer Space Telescope. The targeted sources are extremely diverse and include objects in the local and distant universe. Variations in features allow both qualitative and quantitative studies of physical and chemical processes. MIRI consists of an imager (including low resolution (R=λ/Δλ≈100) spectroscopy and coronography) and a medium resolution spectrometer (R=2000-3000) operating in the 5-28μm wavelength range using 1024x1024 pixel Si:As arrays. The spectrometer uses four IFUs with fields ranging from 3.5 to 7 arcsec. MIRIs sensitivity, orders of magnitude higher compared to Spitzer and 8-m class ground-based telescopes, spatial and spectral resolution make it particularly well suited for studying gases and solids in disks around young stars and in the nuclei of (starburst) galaxies. The sensitive low resolution spectrometer will be ideal to characterize exoplanet atmospheres. MIRI is built in partnership by a European Consortium and the US. The MIRI flight model (FM) is now fully

  15. Lessons from Coronagraphic Imaging with HST that may apply to JWST

    Science.gov (United States)

    Grady, C. A.; Hines, Dean C.; Schneider, Glenn; McElwain, Michael W.

    2017-06-01

    One of the major capabilities offered by JWST is coronagraphic imaging from space, covering the near through mid-IR and optimized for study of planet formation and the evolution of planetary systems. Planning for JWST has resulted in expectations for instrument performance, observation strategies and data reduction approaches. HST with 20 years of coronagraphic imaging offers some experience which may be useful to those planning for JWST. 1) Real astronomical sources do not necessarily conform to expectations. Debris disks may be accompanied by more distant material, and some systems may be conspicuous in scattered light when offering only modest IR excesses. Proto-planetary disks are not constantly illuminated, and thus a single epoch observation of the source may not be sufficient to reveal everything about it. 2) The early expectation with NICMOS was that shallow, 2-roll observations would reveal a wealth of debris disks imaged in scattered light, and that only a limited set of PSF observations would be required. Instead, building up a library of spatially resolved disks in scattered light has proven to require alternate observing strategies, is still on-going, and has taken far longer than expected. 3) A wealth of coronagraphic options with an instrument may not be scientifically informative, unless there is a similar time investment in acquisition of calibration data in support of the science observations. 4) Finally, no one anticipated what can be gleaned from coronagraphic imaging. We should expect similar, unexpected, and ultimately revolutionary discoveries with JWST.

  16. Recovering the Properties of High-redshift Galaxies with Different JWST Broadband Filters

    DEFF Research Database (Denmark)

    Bisigello, L.; Caputi, K. I.; Colina, L.

    2017-01-01

    Imaging with the James Webb Space Telescope (JWST) will allow observations of the bulk of distant galaxies at the epoch of reionization. The recovery of their properties, such as age, color excess , specific star formation rate (sSFR), and stellar mass, will mostly rely on spectral energy distrib...

  17. Fine motor movements while drawing during the encoding phase of a serial verbal recall task reduce working memory performance.

    Science.gov (United States)

    Tindle, Richard; Longstaff, Mitchell G

    2016-02-01

    The time-based resource-sharing (TBRS) model of working memory indicates that secondary tasks that capture attention for relatively long periods can result in the interference of working memory processing and maintenance. The current study investigates if discrete and continuous movements have differing effects on a concurrent, verbal serial recall task. In the listening condition, participants were asked to recall spoken words presented in lists of six. In the drawing conditions, participants performed the same task while producing discrete (star) or continuous (circle) movements. As hypothesised, participants recalled more words overall in the listening condition compared to the combined drawing conditions. The prediction that the continuous movement condition would reduce recall compared to listening was also supported. Fine-grained analysis at each serial position revealed significantly more words were recalled at mid serial positions in the listening condition, with worst recall for the continuous condition at position 5 compared to the listening and discrete conditions. Kinematic analysis showed that participants increased the size and speed of the continuous movements resulting in a similar duration and number of strokes for each condition. The duration of brief pauses in the discrete condition was associated with the number of words recalled. The results indicate that fine motor movements reduced working memory performance; however, it was not merely performing a movement but the type of the movement that determined how resources were diverted. In the context of the TBRS, continuous movements could be capturing attention for longer periods relative to discrete movements, reducing verbal serial recall. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Production of Seamless Superconducting Radio Frequency Cavities from Ultra-fine Grained Niobium, Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Roy Crooks, Ph.D., P.E.

    2009-10-31

    The positron and electron linacs of the International Linear Collider (ILC) will require over 14,000, nine-cell, one meter length, superconducting radio frequency (SRF) cavities [ILC Reference Design Report, 2007]. Manufacturing on this scale will benefit from more efficient fabrication methods. The current methods of fabricating SRF cavities involve deep drawing of the halves of each of the elliptical cells and joining them by high-vacuum, electron beam welding, with at least 19 circumferential welds per cavity. The welding is costly and has undesirable effects on the cavity surfaces, including grain-scale surface roughening at the weld seams. Hydroforming of seamless tubes avoids welding, but hydroforming of coarse-grained seamless tubes results in strain-induced surface roughening. Surface roughness limits accelerating fields, because asperities prematurely exceed the critical magnetic field and become normal conducting. This project explored the technical and economic feasibility of an improved processing method for seamless tubes for hydroforming. Severe deformation of bulk material was first used to produce a fine structure, followed by extrusion and flow-forming methods of tube making. Extrusion of the randomly oriented, fine-grained bulk material proceeded under largely steady-state conditions, and resulted in a uniform structure, which was found to be finer and more crystallographically random than standard (high purity) RRR niobium sheet metal. A 165 mm diameter billet of RRR grade niobium was processed into five, 150 mm I.D. tubes, each over 1.8 m in length, to meet the dimensions used by the DESY ILC hydroforming machine. Mechanical properties met specifications. Costs of prototype tube production were approximately twice the price of RRR niobium sheet, and are expected to be comparable with economies of scale. Hydroforming and superconducting testing will be pursued in subsequent collaborations with DESY and Fermilab. SRF Cavities are used to construct

  19. The influence of nano-scale second-phase particles on deformation of fine grained calcite mylonites

    Science.gov (United States)

    Herwegh, Marco; Kunze, Karsten

    2002-09-01

    Grey and white carbonate mylonites were collected along thrust planes of the Helvetic Alps. They are characterised by very small grain sizes and non-random grain shape (SPO) and crystallographic preferred orientation (CPO). Presumably they deformed in the field of grain size sensitive flow by recrystallisation accommodated intracrystalline deformation in combination with granular flow. Both mylonites show a similar mean grain size, but in the grey mylonites the grain size range is larger, the grain shapes are more elongate and the dynamically recrystallised calcite grains are more often twinned. Grey mylonites have an oblique CPO, while the CPO in white mylonites is symmetric with respect to the shear plane. Combustion analysis and TEM investigations revealed that grey mylonites contain a higher amount of highly structured kerogens with particle sizes of a few tens of nanometers, which are finely dispersed at the grain boundaries. During deformation of the rock, nano-scale particles reduced the migration velocity of grain boundaries by Zener drag resulting in slower recrystallisation rates of the calcite aggregate. In the grey mylonites, more strain increments were accommodated by individual grains before they became refreshed by dynamic recrystallisation than in white mylonites, where grain boundary migration was less hindered and recrystallisation cycles were faster. Consequently, grey mylonites represent 'deformation' microfabrics while white mylonites are characterised by 'recrystallisation' microfabrics. Field geologists must utilise this different deformation behavior when applying the obliquity in CPO and SPO of the respective mylonites as reliable shear sense indicators.

  20. Predicting diurnal variability of fine inorganic aerosols and their gas-phase precursors near downtown Mexico City

    Directory of Open Access Journals (Sweden)

    M. Moya

    2007-08-01

    Full Text Available Partitioning of semi-volatile nitrate and ammonium between the gas and particulate phases is studied combining two thermodynamic models that explicitly include crustal elements and simulate both branches (deliquescence, efflorescence of aerosol behavior and measurements taken near downtown Mexico City during a field campaign conducted in February–March, 2005. Overall, no significant differences between model predictions (within 30% of error are observed for particulate ammonium (PM2.5, PM1. In cases of moderate to high RH (40–70%, mostly occurring during the 1st and 2nd daily sampling periods (06:00–10:00 h, 10:00–14:00 h, LST, 4 h PM2.5 nitrate measurements are predicted within 30%. When RH drops below 30%, characteristic of the afternoon sampling periods (14:00-18:00 h, the efflorescence branch is most consistent with observed PM nitrate. Residual error analysis of these low RH cases suggest that aerosol nitrate loading or sulfate-to-nitrate molar ratio control phase behavior, hence the partitioning of semi-volatile PM2.5 nitrate in gas and particulate phases. Finally, inclusion of crustal elements in the modeling framework reduces the error in predicted PM2.5 ammonium by 25%. These findings, if generally applicable, can help improve air quality modeling in nitrate deficient environments.

  1. Observing transiting planets with JWST -- Prime targets and their synthetic spectral observations

    CERN Document Server

    Mollière, Paul; Bouwman, Jeroen; Henning, Thomas; Lagage, Pierre-Olivier; Min, Michiel

    2016-01-01

    The James Webb Space Telescope will enable astronomers to obtain exoplanet spectra of unprecedented precision. Especially the MIRI instrument may shed light on the nature of the cloud particles obscuring planetary transmission spectra in the optical and near-infrared. We provide self-consistent atmospheric models and synthetic JWST observations for prime exoplanet targets in order to identify spectral regions of interest and estimate the number of transits needed to distinguish between model setups. We select targets which span a wide range in planetary temperature and surface gravity, ranging from super-Earths to giant planets, and have a high expected SNR. For all targets we vary the enrichment, C/O ratio, presence of optical absorbers (TiO/VO) and cloud treatment. We calculate atmospheric structures and emission and transmission spectra for all targets and use a radiometric model to obtain simulated observations. We analyze JWST's ability to distinguish between various scenarios. We find that in very cloud...

  2. Exploring Biases of Atmospheric Retrievals in Simulated JWST Transmission Spectra of Hot Jupiters

    CERN Document Server

    Rocchetto, M; Venot, O; Lagage, P -O; Tinetti, G

    2016-01-01

    With a scheduled launch in October 2018, the James Webb Space Telescope (JWST) is expected to revolutionise the field of atmospheric characterization of exoplanets. The broad wavelength coverage and high sensitivity of its instruments will allow us to extract far more information from exoplanet spectra than what has been possible with current observations. In this paper, we investigate whether current retrieval methods will still be valid in the era of JWST, exploring common approximations used when retrieving transmission spectra of hot Jupiters. To assess biases, we use 1D photochemical models to simulate typical hot Jupiter cloud-free atmospheres and generate synthetic observations for a range of carbon-to-oxygen ratios. Then, we retrieve these spectra using TauREx, a Bayesian retrieval tool, using two methodologies: one assuming an isothermal atmosphere, and one assuming a parametrized temperature profile. Both methods assume constant-with-altitude abundances. We found that the isothermal approximation bi...

  3. An Update on Simulating Imaging, Spectroscopic, and Coronagraphic PSFs for JWST (and WFIRST too!)

    Science.gov (United States)

    Perrin, Marshall D.; Long, Joseph D.; Zimmerman, Neil T.; Van Gorkom, Kyle

    2016-06-01

    Simulated point spread functions (PSFs) are an essential tool in preparing for future space telescopes, supporting pre-launch science simulations, observation planning, and analysis software development. The open-source Python package WebbPSF provides simulated PSFs for all of JWST's instruments and observing modes. We present the latest updates to WebbPSF based on both updated models ofthe assembled telescope optics and recent cryo-test data for the science instruments. Outputs from this latest version of WebbPSF will support the JWST Exposure Time Calculator and the first calls for proposals in the year ahead, among many other uses by the community. Furthermore, the same toolkit also now provides support for simulating PSFs for both the WFI and CGI instruments planned for WFIRST.

  4. Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program

    CERN Document Server

    Stevenson, Kevin B; Bean, Jacob L; Beichman, Charles; Fraine, Jonathan; Kilpatrick, Brian M; Krick, J E; Lothringer, Joshua D; Mandell, Avi M; Valenti, Jeff A; Agol, Eric; Angerhausen, Daniel; Barstow, Joanna K; Birkmann, Stephan M; Burrows, Adam; Cowan, Nicolas B; Crouzet, Nicolas; Cubillos, Patricio E; Curry, S M; Dalba, Paul A; de Wit, Julien; Deming, Drake; Desert, Jean-Michel; Doyon, Rene; Dragomir, Diana; Ehrenreich, David; Fortney, Jonathan J; Munoz, Antonio Garcia; Gibson, Neale P; Gizis, John E; Greene, Thomas P; Harrington, Joseph; Heng, Kevin; Kataria, Tiffany; Kempton, Eliza M -R; Knutson, Heather; Kreidberg, Laura; Lafreniere, David; Lagage, Pierre-Olivier; Line, Michael R; Lopez-Morales, Mercedes; Madhusudhan, Nikku; Morley, Caroline V; Rocchetto, Marco; Schlawin, Everett; Shkolnik, Evgenya L; Shporer, Avi; Sing, David K; Todorov, Kamen O; Tucker, Gregory S; Wakeford, Hannah R

    2016-01-01

    The James Webb Space Telescope will revolutionize transiting exoplanet atmospheric science due to its capability for continuous, long-duration observations and its larger collecting area, spectral coverage, and spectral resolution compared to existing space-based facilities. However, it is unclear precisely how well JWST will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. In this article, we describe a prefatory JWST Early Release Science (ERS) program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful future transiting exoplanet characterization programs. We propose a multi-pronged approach wherein one aspect of the program focuses on observing transits of a single target with all of the recommended observing modes to identify and understand potential systematics, compare transmission spectra at overlapping and neighboring wavelength regions...

  5. Observing Resolved Stellar Populations with the JWST Near-Infrared Spectrograph

    Science.gov (United States)

    Gilbert, K. M.; Beck, T. L.; Karakla, D. M.

    2016-10-01

    The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) will provide a multi-object spectroscopy (MOS) mode through the Micro-Shutter Array (MSA). Each MSA quadrant is a grid of contiguous shutters that can be configured to form slits on more than 100 astronomical targets simultaneously. The combination of JWST's sensitivity and superb resolution in the infrared and NIRSpec's full wavelength coverage over 0.6 to 5 μm will open new parameter space for studies of galaxies and resolved stellar populations alike. We describe a NIRSpec MSA observing scenario of spectroscopy of individual stars in an external galaxy, and investigate the technical challenges posed by this scenario. This use case and others, including a deep galaxy survey and observations of Galactic HII regions, are guiding development of the NIRSpec user interfaces including proposal planning and pipeline calibrations.

  6. Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program

    Science.gov (United States)

    Stevenson, Kevin B.; "Enabling Transiting Exoplanet Science with JWST" workshop attendees

    2016-10-01

    The James Webb Space Telescope (JWST) will likely revolutionize transiting exoplanet atmospheric science; however, it is unclear precisely how well it will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. We will describe a prefatory JWST Early Release Science (ERS) Cycle 1 program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful transiting exoplanet characterization programs in later cycles. We will also present a list of "community targets" that are well suited to achieving these goals. Since most of the community targets do not have well-characterized atmospheres, we have initiated a preparatory HST + Spitzer observing program to determine the presence of obscuring clouds/hazes within their atmospheres. Measurable spectroscopic features are needed to establish the optimal resolution and wavelength regions for exoplanet characterization. We will present preliminary results from this preparatory observing program and discuss their implications on the pending JWST ERS proposal deadline in mid-2017.

  7. Follow-up and characterization of the TESS exoplanets with SOPHIE, SPIRou, and JWST

    Science.gov (United States)

    Crouzet, N.; Bonfils, X.; Delfosse, X.; Boisse, I.; Hébrard, G.; Forveille, T.; Donati, J.-F.; Bouchy, F.; Moutou, C.; Doyon, R.; Artigau, E.; Albert, L.; Malo, L.; Lecavelier des Etangs, A.; Santerne, A.; Author2, J.-P.; Author3, C. E.

    2016-12-01

    The NASA TESS mission will deliver hundreds of transiting exoplanet candidates orbiting bright stars. The spectrometers SOPHIE at OHP and SPIRou at CFHT will be ideal to obtain radial velocities of these candidates, confirm their nature, and derive the planets' masses. These measurements will be crucial to deliver the best targets for atmospheric characterization with JWST. Here, we calculate the required observing time with SOPHIE, SPIRou, and JWST for each of the TESS targets in order to prepare follow-up observations. To infer their potential for JWST, we restrict the calculations to the case of transmission spectroscopy with NIRISS. The radial velocity follow-up of the giant planets (R_p > 4 R_E) could be achieved with SOPHIE, with a median observing time of 3.47 hours per target, and a total observing time of 305 hours that includes the 80% most favorable cases. Several small planets (R_p R_E) could also be confirmed, but most of them would require an unrealistic time investment. On the other hand, SPIRou is ideally suited to the follow-up of the small planets, with a median observing time of 2.65 hours per target, and a median observing time of 4.70 hours for the terrestrial planets in the habitable zone (R_p R_E, S programs with SOPHIE and SPIRou before the first planet candidates are delivered by TESS.

  8. The Planning Process for Multi-Object Spectroscopy with the JWST Near-Infrared Spectrograph

    Science.gov (United States)

    Beck, Tracy L.; Karakla, D. M.; Shyrokov, A.; Pontoppidan, K.; Soderblom, D. R.; Valenti, J. A.; Kassin, S. A.; Gilbert, K.; Blair, W. P.; Muzerolle, J.; Tumlinson, J.; Keyes, C. D.; Pavlovsky, C. M.; LeBlanc, T.

    2014-01-01

    The Near-Infrared Spectrograph (NIRSpec) for the James Webb Space Telescope (JWST) will have a powerful multi-object spectroscopy mode using four configurable Micro-Shutter Arrays (MSAs). The contiguous MSA shutters can be opened to form slits on astronomical targets, for simultaneous spectroscopy of up to 100 sources per exposure. The NIRSpec MSA shutters are in a fixed grid pattern, and careful analysis in the observation planning process will be crucial for optimal definition of science exposures. Our goal is to maximize the number of astronomical science sources observed in the fewest number of MSA slit configurations. We are developing algorithms in the NIRSpec MSA Planning Tool (MPT) to improve the quality of planned observations using several common science observing strategies as test use cases. For example, the needs for planning extremely deep exposures on a small number of JWST discovered z > 10 galaxy candidates will differ significantly from the requirements for planning spectral observations on a representative sample of stars from a galactic star cluster catalog. In this poster, we present a high level overview of our plans to develop and optimize the MPT for the JWST NIRSpec multi-object spectroscopy mode.

  9. NIRCam: Development and Testing of the JWST Near-Infrared Camera

    Science.gov (United States)

    Greene, Thomas; Beichman, Charles; Gully-Santiago, Michael; Jaffe, Daniel; Kelly, Douglas; Krist, John; Rieke, Marcia; Smith, Eric H.

    2011-01-01

    The Near Infrared Camera (NIRCam) is one of the four science instruments of the James Webb Space Telescope (JWST). Its high sensitivity, high spatial resolution images over the 0.6 - 5 microns wavelength region will be essential for making significant findings in many science areas as well as for aligning the JWST primary mirror segments and telescope. The NIRCam engineering test unit was recently assembled and has undergone successful cryogenic testing. The NIRCam collimator and camera optics and their mountings are also progressing, with a brass-board system demonstrating relatively low wavefront error across a wide field of view. The flight model?s long-wavelength Si grisms have been fabricated, and its coronagraph masks are now being made. Both the short (0.6 - 2.3 microns) and long (2.4 - 5.0 microns) wavelength flight detectors show good performance and are undergoing final assembly and testing. The flight model subsystems should all be completed later this year through early 2011, and NIRCam will be cryogenically tested in the first half of 2011 before delivery to the JWST integrated science instrument module (ISIM).

  10. Electronic speckle pattern interferometric testing of JWST primary mirror segment assembly

    Science.gov (United States)

    Smith, Koby Z.; Chaney, David M.; Saif, Babak N.

    2011-09-01

    The James Webb Space Telescope (JWST) Primary Mirror Segment Assembly (PMSA) was required to meet NASA Technology Readiness Level (TRL) 06 requirements in the summer of 2006. These TRL06 requirements included verifying all mirror technology systems level readiness in simulated end-to-end operating conditions. In order to support the aggressive development and technology readiness schedule for the JWST Primary Mirror Segment Assembly (PMSA), a novel approach was implemented to verify the nanometer surface figure distortion effects on an in-process non-polished beryllium mirror surface. At the time that the TRL06 requirements needed to be met, a polished mirror segment had not yet been produced that could have utilized the baselined interferometric optical test station. The only JWST mirror segment available was a finished machined segment with an acid-etched optical surface. Therefore an Electronic Speckle Pattern Interferometer (ESPI) was used in coordination with additional metrology techniques to perform interferometric level optical testing on a non-optical surface. An accelerated, rigorous certification program was quickly developed for the ESPI to be used with the unfinished optical surface of the primary mirror segment. The ESPI was quickly implemented into the PMSA test program and optical testing was very successful in quantifying the nanometer level surface figure deformation changes in the PMSA due to assembly, thermal cycling, vibration, and acoustic testing. As a result of the successful testing, the PMSA passed all NASA TRL06 readiness requirements.

  11. Anne Fine

    Directory of Open Access Journals (Sweden)

    Philip Gaydon

    2015-04-01

    Full Text Available An interview with Anne Fine with an introduction and aside on the role of children’s literature in our lives and development, and our adult perceptions of the suitability of childhood reading material.Since graduating from Warwick in 1968 with a BA in Politics and History, Anne Fine has written over fifty books for children and eight for adults, won the Carnegie Medal twice (for Goggle-Eyes in 1989 and Flour Babies in 1992, been a highly commended runner-up three times (for Bill’s New Frock in 1989, The Tulip Touch in 1996, and Up on Cloud Nine in 2002, been shortlisted for the Hans Christian Andersen Award (the highest recognition available to a writer or illustrator of children’s books, 1998, undertaken the positon of Children’s Laureate (2001-2003, and been awarded an OBE for her services to literature (2003. Warwick presented Fine with an Honorary Doctorate in 2005.Philip Gaydon’s interview with Anne Fine was recorded as part of the ‘Voices of the University’ oral history project, co-ordinated by Warwick’s Institute of Advanced Study.

  12. Supermassive Dark Stars: Detectable in JWST and HST

    CERN Document Server

    Freese, K; Valluri, M; Ilie, C; Spolyar, D; Bodenheimer, P

    2010-01-01

    The first stars to form in the history of the universe may have been powered by dark matter annihilation rather than by fusion. This new phase of stellar evolution may have lasted millions to billions of years. These dark stars can grow to be very large, > 10^5 solar masses, and are relatively cool (~10^4 K). They are also very bright, being potentially detectable in the upcoming James Webb Space Telescope or even the Hubble Space Telescope. Once the dark matter runs out, the dark stars have a short fusion phase, before collapsing into black holes (BH). The resulting BH could serve as seeds for the (unexplained) supermassive black holes at high redshift and at the centers of galaxies.

  13. Observing Planetary Nebulae with JWST and Extremely Large Telescopes

    Science.gov (United States)

    Sahai, Raghvendra

    2015-01-01

    Most stars in the Universe that leave the main sequence in a Hubble time will end their lives evolving through the Planetary Nebula (PN) evolutionary phase. The heavy mass loss which occurs during the preceding AGB phase is important across astrophysics, dramatically changing the course of stellar evolution, dominantly contributing to the dust content of the interstellar medium, and influencing its chemical composition. The evolution from the AGB phase to the PN phases remains poorly understood, especially the dramatic transformation that occurs in the morphology of the mass-ejecta as AGB stars and their round circumstellar envelopes evolve into mostly PNe, the majority of which deviate strongly from spherical symmetry. In addition, although the PN [OIII] luminosity function (PNLF) has been used as a standard candle (on par with distance indicators such as Cepheids), we do not understand why it works. It has been argued that the resolution of these issues may be linked to binarity and associated processes such as mass transfer and common envelope evolution.Thus, understanding the formation and evolution of PNe is of wide astrophysical importance. PNe have long been known to emit across a very large span of wavelengths, from the radio to X-rays. Extensive use of space-based observatories at X-ray (Chandra/ XMM-Newton), optical (HST) and far-infrared (Spitzer, Herschel) wavelengths in recent years has produced significant new advances in our knowledge of these objects. Given the expected advent of the James Webb Space Telescope in the near future, and ground-based Extremely Large Telescope(s) somewhat later, this talk will focus on future high-angular-resolution, high-sensitivity observations at near and mid-IR wavelengths with these facilities that can help in addressing the major unsolved problems in the study of PNe.

  14. Observations of Transiting Exoplanets with the James Webb Space Telescope (JWST), Publications of the Astronomical Society of the Pacific (PASP), December 2014

    CERN Document Server

    Beichman, Charles; Knutson, Heather; Smith, Roger; Dressing, Courtney; Latham, David; Deming, Drake; Lunine, Jonathan; Lagage, Pierre-Olivier; Sozzetti, Alessandro; Beichman, Charles; Sing, David; Kempton, Eliza; Ricker, George; Bean, Jacob; Kreidberg, Laura; Bouwman, Jeroen; Crossfield, Ian; Christiansen, Jessie; Ciardi, David; Fortney, Jonathan; Albert, Loïc; Doyon, René; Rieke, Marcia; Rieke, George; Clampin, Mark; Greenhouse, Matt; Goudfrooij, Paul; Hines, Dean; Keyes, Tony; Lee, Janice; McCullough, Peter; Robberto, Massimo; Stansberry, John; Valenti, Jeff; Deroo, Pieter D; Mandell, Avi; Ressler, Michael E; Shporer, Avi; Swain, Mark; Vasisht, Gautam; Carey, Sean; Krick, Jessica; Birkmann, Stephan; Ferruit, Pierre; Giardino, Giovanna; Greene, Tom; Howell, Steve

    2014-01-01

    This article summarizes a workshop held on March, 2014, on the potential of the James Webb Space Telescope (JWST) to revolutionize our knowledge of the physical properties of exoplanets through transit observations. JWST's unique combination of high sensitivity and broad wavelength coverage will enable the accurate measurement of transits with high signal-to-noise. Most importantly, JWST spectroscopy will investigate planetary atmospheres to determine atomic and molecular compositions, to probe vertical and horizontal structure, and to follow dynamical evolution, i.e. exoplanet weather. JWST will sample a diverse population of planets of varying masses and densities in a wide variety of environments characterized by a range of host star masses and metallicities, orbital semi-major axes and eccentricities. A broad program of exoplanet science could use a substantial fraction of the overall JWST mission.

  15. Optical Coating Performance for Heat Reflectors of the JWST-ISIM Electronic Component

    Science.gov (United States)

    Rashford, Robert A.; Perrygo, Charles M.; Garrison, Matthew B.; White, Bryant K.; Threat, Felix T.; Quijada, Manuel A.; Jeans, James W.; Huber, Frank K.; Bousquet, Robert R.; Shaw, Dave

    2011-01-01

    A document discusses a thermal radiator design consisting of lightweight composite materials and low-emittance metal coatings for use on the James Webb Space Telescope (JWST) structure. The structure will have a Thermal Subsystem unit to provide passive cooling to the Integrated Science Instrument Module (ISIM) control electronics. The ISIM, in the JWST observatory, is the platform that provides the mounting surfaces for the instrument control electronics. Dissipating the control electronic generated-heat away from JWST is of paramount importance so that the spacecraft s own heat does not interfere with the infrared-light gathering of distant cosmic sources. The need to have lateral control in the emission direction of the IEC (ISIM Electronics Compartment) radiators led to the development of a directional baffle design that uses multiple curved mirrorlike surfaces. This concept started out from the so-called Winston non-imaging optical concentrators that use opposing parabolic reflector surfaces, where each parabola has its focus at the opposite edge of the exit aperture. For this reason they are often known as compound parabolic concentrators or CPCs. This radiator system with the circular section was chosen for the IEC reflectors because it offers two advantages over other designs. The first is that the area of the reflector strips for a given radiator area is less, which results in a lower mass baffle assembly. Secondly, the fraction of energy emitted by the radiator strips and subsequently reflected by the baffle is less. These fewer reflections reduced the amount of energy that is absorbed and eventually re-emitted, typically in a direction outside the design emission range angle. A baffle frame holds the mirrors in position above a radiator panel on the IEC. Together, these will direct the majority of the heat from the IEC above the sunshield away towards empty space.

  16. Unveiling the First Black Holes With JWST:Multi-wavelength Spectral Predictions

    Science.gov (United States)

    Natarajan, Priyamvada; Pacucci, Fabio; Ferrara, Andrea; Agarwal, Bhaskar; Ricarte, Angelo; Zackrisson, Erik; Cappelluti, Nico

    2017-04-01

    Growing supermassive black holes (∼ {10}9 {M}ȯ ) that power luminous z> 6 quasars from light seeds—the remnants of the first stars—within a Gyr of the Big Bang poses a timing challenge. The formation of massive black hole seeds via direct collapse with initial masses ∼ {10}4{--}{10}5 {M}ȯ alleviates this problem. Viable direct-collapse black hole formation sites, the satellite halos of star-forming galaxies, merge and acquire stars to produce a new, transient class of high-redshift objects, obese black hole galaxies (OBGs). The accretion luminosity outshines that of the stars in OBGs. We predict the multi-wavelength energy output of OBGs and growing Pop III remnants at z = 9 for standard and slim disk accretion, as well as high and low metallicities of the associated stellar population. We derive robust selection criteria for OBGs—a pre-selection to eliminate blue sources, followed by color–color cuts ([{F}090W-{F}220W]> 0;-0.3< [{F}200W-{F}444W]< 0.3) and the ratio of X-ray flux to rest-frame optical flux ({F}X/{F}444W\\gg 1). Our cuts sift out OBGs from other bright, high- and low-redshift contaminants in the infrared. OBGs with predicted {M}{AB}< 25 are unambiguously detectable by the Mid-Infrared Instrument (MIRI), on the upcoming James Webb Space Telescope (JWST). For parameters explored here, growing Pop III remnants with predicted {M}{AB}< 30 will likely be undetectable by JWST. We demonstrate that JWST has the power to discriminate between initial seeding mechanisms.

  17. High contrast imaging with the JWST-NIRSpec Integral Field Unit

    Science.gov (United States)

    Ygouf, Marie; Beichman, Charles A.; Hodapp, Klaus W.; Roellig, Thomas L.; NIRCam GTO

    2017-06-01

    With its integral field unit, the near-infrared spectrograph NIRSpec on JWST will allow to measure high-resolution spectra into the 3-5 μm range with an increased sensitivity over ground-based systems. This capability will considerably extend our knowledge of brown dwarfs and bright exoplanets at large separations from their host star. But because there is not any coronagraph on NIRSpec, the performance in term of contrast at close separation will be extremely limited. In this communication, we explore possibilities to further push this limitation by comparing different observing strategies and associated post-processing techniques.

  18. New and Better Near-Infrared Detectors for JWST Near Infrared Spectrograph

    Science.gov (United States)

    Rauscher, Bernard J.; Mott, D. Brent; Wen, Yiting; Linder, Don; Greenhouse, Matthew A.; Hill, Robert J.

    2014-01-01

    ESA and NASA recently selected two 5 m cutoff Teledyne H2RG sensor chip assemblies (SCA) for flight on the James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec). These HgCdTe SCAs incorporate Teledynes improved barrier layer design that eliminates the degradation that affected earlier JWST H2RGs(Rauscher et al. 2012a). The better indium barrier, together with other design changes, has improved the performance and reliability of JWSTs SCAs. In this article, we describe the measured performance characteristics that most directly affect scientific observations including read noise, total noise, dark current, quantum efficiency (QE), and image persistence. As part of measuring QE, we measured the quantum yield as a function of photon energy,, and found that it exceeds unity for photon energies E (2.65.2) Eg, where Eg is the HgCdTe bandgap energy. This corresponds to. 2 m for NIRSpecs 5 m cutoff HgCdTe. Our measurements agree well with a previous measurement by McCullough et al. (2008) for. 1.3. For 1.3, we find a slower increase in with photon energy than McCullough et al. did. However, and as McCullough et al. note, their two state model of the yield process is not valid for large 1.

  19. Mechanical blind gap measurement tool for alignment of the JWST Optical Telescope Element

    Science.gov (United States)

    Liepmann, Till

    2016-09-01

    This paper describes a novel gap gauge tool that is used to provide an independent check of the James Webb Space Telescope (JWST) Optical Telescope Element (OTE) primary mirror alignment. Making accurate measurements of the mechanical gaps between the OTE mirror segments is needed to verify that the segments were properly aligned relative to each other throughout the integration and test of the 6.6 meter telescope. The gap between the Primary Mirror Segment Assemblies (PMSA) is a sensitive indicator of the relative clocking and decenter. Further, the gap measurements are completely independent of all the other measurements use in the alignment process (e.g. laser trackers and laser radar). The gap measurement is a challenge, however, that required a new approach. Commercial gap measurements tools were investigated; however no suitable solution is available. The challenge of this measurement is due to the required 0.1 mm accuracy, the close spacing of the mirrors segments (approximately 3-9mm), the acute angle between the segment sides (approximately 4 degrees), and the difficult access to the blind gap. Several techniques were considered and tested before selecting the gauge presented here. This paper presents the theory, construction and calibration of the JWST gap gauge that is being used to measure and verify alignment of the OTE primary mirror segments.

  20. The impact of JWST broad-band filter choice on photometric redshift estimation

    CERN Document Server

    Bisigello, L; Colina, L; Fèvre, O Le; Nørgaard-Nielsen, H U; Pérez-González, P G; Pye, J; van der Werf, P; Ilbert, O; Grogin, N; Koekemoer, A

    2016-01-01

    The determination of galaxy redshifts in James Webb Space Telescope (JWST)'s blank-field surveys will mostly rely on photometric estimates, based on the data provided by JWST's Near-Infrared Camera (NIRCam) at 0.6-5.0 {\\mu}m and Mid Infrared Instrument (MIRI) at {\\lambda}>5.0 {\\mu}m. In this work we analyse the impact of choosing different combinations of NIRCam and MIRI broad-band filters (F070W to F770W), as well as having ancillary data at {\\lambda}=10, but the zphot quality significantly degrades at S/N<=5. Adding MIRI photometry with one magnitude brighter depth than the NIRCam depth allows for a redshift recovery of 83-99%, depending on SED type, and its effect is particularly noteworthy for galaxies with nebular emission. The vast majority of NIRCam galaxies with [F150W]=29 AB mag at z=7-10 will be detected with MIRI at [F560W, F770W]<28 mag if these sources are at least mildly evolved or have spectra with emission lines boosting the mid-infrared fluxes.

  1. The James Webb STEM Innovation Project: Bringing JWST to the Education Community

    Science.gov (United States)

    Eisenhamer, Bonnie; Harris, J.; Ryer, H.; Taylor, J.; Bishop, M.

    2012-01-01

    Building awareness of a NASA mission prior to launch and connecting that mission to the education community can be challenging. In order to address this challenge, the Space Telescope Science Institute's Office of Public Outreach has developed the James Webb STEM innovation Project (SIP) - an interdisciplinary project that focuses on the engineering aspects and potential scientific discoveries of JWST, while incorporating elements of project-based learning. Students in participating schools will use skills from multiple subject areas to research an aspect of the JWST's design or potential science and create models, illustrated essays, or technology-based projects to demonstrate their learning. Student projects will be showcased during special events at select venues in the project states - thus allowing parents and community members to also be benefactors of the project. Currently, the SIP is being piloted in New York, California, and Maryland. In addition, we will be implementing the SIP in partnership with NASA Explorer Schools in the states of New Mexico, Michigan, Texas, Tennessee, and Iowa.

  2. An image-plane algorithm for JWST's non-redundant aperture mask data

    CERN Document Server

    Greenbaum, Alexandra Z; Sivaramakrishnan, Anand; Lacour, Sylvestre

    2014-01-01

    The high angular resolution technique of non-redundant masking (NRM) or aperture masking interferometry (AMI) has yielded images of faint protoplanetary companions of nearby stars from the ground. AMI on James Webb Space Telescope (JWST)'s Near Infrared Imager and Slitless Spectrograph (NIRISS) has a lower thermal background than ground-based facilites and does not suffer from atmospheric instability. NIRISS AMI images are likely to have 90 - 95% Strehl ratio between 2.77 and 4.8 micron. In this paper we quantify factors that limit the raw point source contrast of JWST NRM. We develop an analytic model of the NRM point spread function which includes different optical path delays (pistons) between mask holes and fit the model parameters with image plane data. It enables a straightforward way to exclude bad pixels, is suited to limited fields of view, and can incorporate effects such as intra-pixel sensitivity variations. We simulate various sources of noise to estimate their effect on the standard deviation of...

  3. The infrared signatures of very small grains in the Universe seen by JWST

    CERN Document Server

    Pilleri, Paolo; Joblin, Christine

    2015-01-01

    The near- and mid-IR spectrum of many astronomical objects is dominated by emission bands due to UV-excited polycyclic aromatic hydrocarbons (PAH) and evaporating very small grains (eVSG). Previous studies with the ISO, Spitzer and AKARI space telescopes have shown that the spectral variations of these features are directly related to the local physical conditions that induce a photo-chemical evolution of the band carriers. Because of the limited sensitivity and spatial resolution, these studies have focused mainly on galactic star-forming regions. We discuss how the advent of JWST will allow to extend these studies to previously unresolved sources such as near-by galaxies, and how the analysis of the infrared signatures of PAHs and eVSGs can be used to determine their physical conditions and chemical composition.

  4. The Mid-Infrared Instrument for JWST, II: Design and Build

    CERN Document Server

    Wright, G S; Goodson, G B; Rieke, G H; Aitink-Kroes, Gabby; Amiaux, J; Aricha-Yanguas, Ana; Azzolini, Ruyman; Banks, Kimberly; Barrado-Navascues, D; Belenguer-Davila, T; Bloemmart, J A D L; Bouchet, Patrice; Brandl, B R; Colina, L; Detre, Ors; Diaz-Catala, Eva; Eccleston, Paul; Friedman, Scott D; Garcia-Marin, Macarena; Guedel, Manuel; Glasse, Alistair; Glauser, Adrian M; Greene, T P; Groezinger, Uli; Grundy, Tim; Hastings, Peter; Henning, Th; Hofferbert, Ralph; Hunter, Faye; Jessen, N C; Justtanont, K; Karnik, Avinash R; Khorrami, Mori A; Krause, Oliver; Labiano, Alvaro; Lagage, P -O; Langer, Ulrich; Lemke, Dietrich; Lim, Tanya; Lorenzo-Alvarez, Jose; Mazy, Emmanuel; McGowan, Norman; Meixner, M E; Morris, Nigel; Morrison, Jane E; Mueller, Friedrich; Norgaard-Nielson, H -U; Olofsson, Goeran; O'Sullivan, Brian; Pel, J -W; Penanen, Konstantin; Petach, M B; Pye, J P; Ray, T P; Renotte, Etienne; Renouf, Ian; Ressler, M E; Samara-Ratna, Piyal; Scheithauer, Silvia; Schneider, Analyn; Shaughnessy, Bryan; Stevenson, Tim; Sukhatme, Kalyani; Swinyard, Bruce; Sykes, Jon; Thatcher, John; Tikkanen, Tuomo; van Dishoeck, E F; Waelkens, C; Walker, Helen; Wells, Martyn; Zhender, Alex

    2015-01-01

    The Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST) provides measurements over the wavelength range 5 to 28.5 microns. MIRI has, within a single 'package', four key scientific functions: photometric imaging, coronagraphy, single-source low-spectral resolving power (R ~ 100) spectroscopy, and medium-resolving power (R ~ 1500 to 3500) integral field spectroscopy. An associated cooler system maintains MIRI at its operating temperature of < 6.7 K. This paper describes the driving principles behind the design of MIRI, the primary design parameters, and their realization in terms of the 'as-built' instrument. It also describes the test program that led to delivery of the tested and calibrated Flight Model to NASA in 2012, and the confirmation after delivery of the key interface requirements.

  5. Model predictions and observed performance of JWST's cryogenic position metrology system

    Science.gov (United States)

    Lunt, Sharon R.; Rhodes, David; DiAntonio, Andrew; Boland, John; Wells, Conrad; Gigliotti, Trevis; Johanning, Gary

    2016-07-01

    The James Webb Space Telescope (JWST) cryogenic testing requires measurement systems that both obtain a very high degree of accuracy and can function in that environment. Close-range photogrammetry was identified as meeting those criteria. Testing the capability of a close-range photogrammetric system prior to its existence is a challenging problem. Computer simulation was chosen over building a scaled mock-up to allow for increased flexibility in testing various configurations. Extensive validation work was done to ensure that the actual as-built system meets accuracy and repeatability requirements. The simulated image data predicted the uncertainty in measurement to be within specification and this prediction was borne out experimentally. Uncertainty at all levels was verified experimentally to be <0.1 mm.

  6. Reconstructing Emission from Pre-Reionization Sources with Cosmic Infrared Background Fluctuation Measurements by the JWST

    Science.gov (United States)

    Kashlinsky, A.; Mather, J. C.; Helgason, K.; Arendt, R. G.; Bromm, V.; Moseley, S. H.

    2015-01-01

    We present new methodology to use cosmic infrared background (CIB) fluctuations to probe sources at 10 less than or approx. equal to z less than or approx. equal to 30 from a James Webb Space Telescope (JWST) NIRCam configuration that will isolate known galaxies to 28 AB mag at 0.55 m. At present significant mutually consistent source-subtracted CIB fluctuations have been identified in the Spitzer and AKARI data at 25 m, but we demonstrate internal inconsistencies at shorter wavelengths in the recent CIBER data. We evaluate CIB contributions from remaining galaxies and show that the bulk of the high-z sources will be in the confusion noise of the NIRCam beam, requiring CIB studies. The accurate measurement of the angular spectrum of the fluctuations and probing the dependence of its clustering component on the remaining shot noise power would discriminate between the various currently proposed models for their origin and probe the flux distribution of its sources. We show that the contribution to CIB fluctuations from remaining galaxies is large at visible wavelengths for the current instruments precluding probing the putative Lyman-break of the CIB fluctuations. We demonstrate that with the proposed JWST configuration such measurements will enable probing the Lyman-break. We develop a Lyman-break tomography method to use the NIRCam wavelength coverage to identify or constrain, via the adjacent two-band subtraction, the history of emissions over 10 less than or approx. equal to z less than or approx. equal to 30 as the universe comes out of the Dark Ages. We apply the proposed tomography to the current SpitzerIRAC measurements at 3.6 and 4.5 m, to find that it already leads to interestingly low upper limit on emissions at z greater than or approx. equal to 30.

  7. Reconstructing Emission from Pre-reionization Sources with Cosmic Infrared Background Fluctuation Measurements by the JWST

    Science.gov (United States)

    Kashlinsky, A.; Mather, J. C.; Helgason, K.; Arendt, R. G.; Bromm, V.; Moseley, S. H.

    2015-05-01

    We present new methodology to use cosmic infrared background (CIB) fluctuations to probe sources at 10≲ z≲ 30 from a James Webb Space Telescope (JWST)/NIRCam configuration that will isolate known galaxies to 28 AB mag at 0.5-5 μm. At present significant mutually consistent source-subtracted CIB fluctuations have been identified in the Spitzer and AKARI data at ˜2-5 μm, but we demonstrate internal inconsistencies at shorter wavelengths in the recent CIBER data. We evaluate CIB contributions from remaining galaxies and show that the bulk of the high-z sources will be in the confusion noise of the NIRCam beam, requiring CIB studies. The accurate measurement of the angular spectrum of the fluctuations and probing the dependence of its clustering component on the remaining shot noise power would discriminate between the various currently proposed models for their origin and probe the flux distribution of its sources. We show that the contribution to CIB fluctuations from remaining galaxies is large at visible wavelengths for the current instruments precluding probing the putative Lyman-break of the CIB fluctuations. We demonstrate that with the proposed JWST configuration such measurements will enable probing the Lyman-break. We develop a Lyman-break tomography method to use the NIRCam wavelength coverage to identify or constrain, via the adjacent two-band subtraction, the history of emissions over 10≲ z≲ 30 as the universe comes out of the “Dark Ages.” We apply the proposed tomography to the current Spitzer/IRAC measurements at 3.6 and 4.5 μm, to find that it already leads to interestingly low upper limit on emissions at z≳ 30.

  8. Deciphering the Hot Giant Atmospheres Orbiting Nearby Extrasolar Systems with JWST

    Science.gov (United States)

    Afrin Badhan, Mahmuda; Batalha, Natasha; Deming, Drake; Domagal-Goldman, Shawn; HEBRARD, Eric; Kopparapu, Ravi Kumar; Irwin, Patrick Gerard Joseph

    2016-10-01

    Unique and exotic planets give us an opportunity to understand how planetary systems form and evolve over their lifetime, by placing our own planetary system in the context of the vastly different extrasolar systems that are being continually discovered by present space missions. With orbital separations that are less than one-tenth of the Mercury-Sun distance, these close-in planets provide us with valuable insights about the host stellar atmosphere and planetary atmospheres subjected to their enormous stellar insolation. Observed spectroscopic signatures reveal all spectrally active species in a planet, along with information about its thermal structure and dynamics, allowing us to characterize the planet's atmosphere. NASA's upcoming missions will give us the high-resolution spectra necessary to constrain the atmospheric properties with unprecedented accuracy. However, to interpret the observed signals from exoplanetary transit events with any certainty, we need reliable atmospheric retrieval tools that can model the expected observables adequately. In my work thus far, I have built a Markov Chain Monte Carlo (MCMC) convergence scheme, with an analytical radiative equilibrium formulation for the thermal structures, within the NEMESIS atmospheric modeling tool, to allow sufficient (and efficient) exploration of the parameter space. I also augmented the opacity tables to improve the speed and reliability of retrieval models. I then utilized this upgraded version to infer the pressure-temperature (P-T) structures and volume-mixing ratios (VMRs) of major gas species in hot Jupiter dayside atmospheres, from their emission spectra. I have employed a parameterized thermal structure to retrieve plausible P-T profiles, along with altitude-invariant VMRs. Here I show my retrieval results on published datasets of HD189733b, and compare them with both medium and high spectral resolution JWST/NIRSPEC simulations. In preparation for the upcoming JWST mission, my current work

  9. The Galactic Center Seen Through the Precise, Multiplexed Eye of JWST

    Science.gov (United States)

    Lu, Jessica R.

    2013-01-01

    The Galactic center harbors the closest supermassive black hole and contains warm, turbulent molecular clouds, dense stellar populations, and some of the most active star forming regions in the Milky Way. These unique conditions make the Galactic Center a compelling target for understanding how star formation varies with environment, how nuclear star clusters in galaxies evolve, and how supermassive black holes influence their surroundings. Detailed studies of the Galactic center have previously been conducted with ground-based telescopes equipped with adaptive optics in pencil-beam studies. However, Galactic center studies can be dramatically expanded with JWST's combination of large fields-of-view (FOV) and high spatial resolution in the infrared. Of particular relevance for the Galactic Center are NIRCam's suite of narrow-band imaging filters and NIRSpec's IFU spectrograph. The narrow-band imaging should provide precise astrometry, rough spectral types, and emission line maps for ~50,000 stars within a 2' x 2' FOV, while follow up IFU spectroscopy will give precise types and radial velocities for the most interesting subsets of stars. Potential results include: (1) counting the intermediate age red and yellow supergiants that will give information about the recent star formation history; (2) measuring the initial mass function below 1 Msun and studying young stellar objects in known and new young star clusters; (3) using 3D dynamics to model the kinematic evolution of the entire nuclear cluster, find hypervelocity stars, and trace the orbits of gas features and clusters in the region. Galactic Center observations with JWST will give us a more complete picture of the gas, stars, black hole, and their interactions in this dynamic region.

  10. Exploring Biases of Atmospheric Retrievals in Simulated JWST Transmission Spectra of Hot Jupiters

    Science.gov (United States)

    Rocchetto, M.; Waldmann, I. P.; Venot, O.; Lagage, P.-O.; Tinetti, G.

    2016-12-01

    With a scheduled launch in 2018 October, the James Webb Space Telescope (JWST) is expected to revolutionize the field of atmospheric characterization of exoplanets. The broad wavelength coverage and high sensitivity of its instruments will allow us to extract far more information from exoplanet spectra than what has been possible with current observations. In this paper, we investigate whether current retrieval methods will still be valid in the era of JWST, exploring common approximations used when retrieving transmission spectra of hot Jupiters. To assess biases, we use 1D photochemical models to simulate typical hot Jupiter cloud-free atmospheres and generate synthetic observations for a range of carbon-to-oxygen ratios. Then, we retrieve these spectra using TauREx, a Bayesian retrieval tool, using two methodologies: one assuming an isothermal atmosphere, and one assuming a parameterized temperature profile. Both methods assume constant-with-altitude abundances. We found that the isothermal approximation biases the retrieved parameters considerably, overestimating the abundances by about one order of magnitude. The retrieved abundances using the parameterized profile are usually within 1σ of the true state, and we found the retrieved uncertainties to be generally larger compared to the isothermal approximation. Interestingly, we found that by using the parameterized temperature profile we could place tight constraints on the temperature structure. This opens the possibility of characterizing the temperature profile of the terminator region of hot Jupiters. Lastly, we found that assuming a constant-with-altitude mixing ratio profile is a good approximation for most of the atmospheres under study.

  11. SCASim: A Flexible and Reusable Detector Simulator for the MIRI instrument of the JWST

    Science.gov (United States)

    Beard, S.; Morin, J.; Gastaud, R.; Azzollini, R.; Bouchet, P.; Chaintreuil, S.; Lahuis, F.; Littlejohns, O.; Nehme, C.; Pye, J.

    2012-09-01

    The JWST Mid Infrared Instrument (MIRI) operates in the 5-28μm wavelength range and can be configured for imaging, coronographic imaging, long-slit, low-resolution spectroscopy or medium resolution spectroscopy with an integral field unit. SCASim is one of a suite of simulators which operate together to simulate all the different modes of the instrument. These simulators are essential for the efficient operation of MIRI; allowing more accurate planning of MIRI observations on sky or during the pre-launch testing of the instrument. The data generated by the simulators are essential for testing the data pipeline software. The simulators not only need to reproduce the behaviour of the instrument faithfully, they also need to be adaptable so that information learned about the instrument during the pre-launch testing and in-orbit commissioning can be fed back into the simulation. SCASim simulates the behaviour of the MIRI detectors, taking into account cosmetic effects, quantum efficiency, shot noise, dark current, read noise, amplifier layout, cosmic ray hits, etc... The software has benefited from three major design choices. First, the development of a suite of MIRI simulators, rather than single simulator, has allowed MIRI simulators to be developed in parallel by different teams, with each simulator able to concentrate on one particular area. SCASim provides a facility common to all the other simulators and saves duplication of effort. Second, SCASim has a Python-based object-oriented design which makes it easier to adapt as new information about the instrument is learned during testing. Third, all simulator parameters are maintained in external files, rather than being hard coded in the software. These design choices have made SCASim highly reusable. In its present form it can be used to simulate any JWST detector, and it can be adapted for future instruments with similar, photon-counting detectors.

  12. Accretion disks before (?) the main planet formation phase

    NARCIS (Netherlands)

    Dominik, C.

    2009-01-01

    Protoplanetary disks are the sites of planet formation and therefore one of the foremost targets of future facilities in astronomy. In this review, I will discuss the main options for using JWST and concurrent facilities to study the early, gas-rich, massive phases of protoplanetary disks. We discus

  13. Simulated JWST/NIRISS Spectroscopy of Anticipated TESS Planets and Selected Super-Earths Discovered from K2 and Ground-Based Surveys

    Science.gov (United States)

    Louie, Dana; Albert, Loic; Deming, Drake

    2017-01-01

    The 2018 launch of James Webb Space Telescope (JWST), coupled with the 2017 launch of the Transiting Exoplanet Survey Satellite (TESS), heralds a new era in Exoplanet Science, with TESS projected to detect over one thousand transiting sub-Neptune-sized planets (Ricker et al, 2014), and JWST offering unprecedented spectroscopic capabilities. Sullivan et al (2015) used Monte Carlo simulations to predict the properties of the planets that TESS is likely to detect, and published a catalog of 962 simulated TESS planets. Prior to TESS launch, the re-scoped Kepler K2 mission and ground-based surveys such as MEarth continue to seek nearby Earth-like exoplanets orbiting M-dwarf host stars. The exoplanet community will undoubtedly employ JWST for atmospheric characterization follow-up studies of promising exoplanets, but the targeted planets for these studies must be chosen wisely to maximize JWST science return. The goal of this project is to estimate the capabilities of JWST’s Near InfraRed Imager and Slitless Spectrograph (NIRISS)—operating with the GR700XD grism in Single Object Slitless Spectrography (SOSS) mode—during observations of exoplanets transiting their host stars. We compare results obtained for the simulated TESS planets, confirmed K2-discovered super-Earths, and exoplanets discovered using ground-based surveys. By determining the target planet characteristics that result in the most favorable JWST observing conditions, we can optimize the choice of target planets in future JWST follow-on atmospheric characterization studies.

  14. Probing the dusty inhabitants of the Local Group Galaxies: JWST/MIRI colors of infrared stellar populations

    Science.gov (United States)

    Jones, Olivia; Meixner, Margaret

    2016-01-01

    The assembly of galaxies involves the life cycle of mass, metal enrichment and dust that JWST will probe. Detailed studies of nearby galaxies provides guidance for interpreting the more distant forming galaxies. JWST/MIRI will enable stellar population studies akin to work done with HST on the Local Group galaxies but over a new wavelength range. MIRI's imaging capability over nine photometric bands from 5 to 28 microns is particularly suited to survey stars with an infrared excess and to detangle the extinction or thermal emission from various species of dust. These dusty stellar populations include young stellar objects, evolved stars and supernovae that are bright in the infrared. Using the rich Spitzer-IRS spectroscopic dataset and spectral classifications from the Surveying the Agents of Galaxy Evolution (SAGE)-Spectroscopic survey of over a thousand objects in the Magellanic Clouds, we calculate the expected flux -densities and colors in the MIRI broadband filters for these prominent infrared sources. We uses these fluxes to illustrate what JWST will see in stellar population studies for other Local Group galaxies. JWST/MIRI observations of infrared sources in Local Group Galaxies will constrain the life cycle of galaxies through their dust emission. For example, how much of the interstellar dust is supplied by dying stars? Do the number of young stellar objects agree with star formation diagnostic for the galaxy? We discuss the locations of the post- and pre-main-sequence populations in MIRI color-color and color-magnitude space and examine which filters are best for identifying populations of sources. We connect these results to existing galaxies with HST data for instance Andromeda and M33.

  15. Experimental Profiling of a Non-truncated Focused Gaussian Beam and Fine-tuning of the Quadratic Phase in the Fresnel Gaussian Shape Invariant

    Energy Technology Data Exchange (ETDEWEB)

    S., Juan Manuel Franco [Center of Investigation (CIO) (Mexico); Cywiak, Moises [Center of Investigation (CIO) (Mexico); Cywiak, David [National Metrology Center (Mexico); Mourad, Idir [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-06-24

    A homodyne profiler is used for recording the intensity distribution of focused non-truncated Gaussian beams. The spatial distributions are obtained at planes in the vicinity of the back-focal plane of a focusing lens placed at different distances from a He–Ne laser beam with a Gaussian intensity profile. Comparisons of the experimental data with those obtained from the analytical equations for an ideal focusing lens allow us to propose formulae to fine-tune the quadratic term in the Fresnel Gaussian shape invariant at each interface of the propagated field. Furthermore, we give analytical expressions to calculate adequately the propagation of the field through an optical system.

  16. Exploring for Galaxies in the First Billion Years with Hubble and Spitzer - Pathfinding for JWST

    Science.gov (United States)

    Illingworth, Garth D.

    2017-01-01

    Hubble has revolutionized the field of distant galaxies through its deep imaging surveys, starting with the Hubble Deep Field (HDF) in 1995. That first deep survey revealed galaxies at redshift z~1-3 that provided insights into the development of the Hubble sequence. Each new HST instrument has explored new regimes, through the peak of star formation at z~2-3, just 2-3 billion years after the Big Bang, to our first datasets at a billion years at z~6, and then earlier to z~11. HST's survey capabilities were enhanced by 40X with ACS, and then similarly with the WFC3/IR, which opened up the first billion years to an unforeseen degree. I will discuss what we have learned from the remarkable HST and Spitzer imaging surveys (HUDF, GOODS, HUDF09/12 and CANDELS), as well as surveys of clusters like the Hubble Frontier Fields (HFF). Lensing clusters provide extraordinary opportunities for characterizing the faintest earliest galaxies, but also present extraordinary challenges. Together these surveys have resulted in the measurement of the volume density of galaxies in the first billion years down to astonishingly faint levels. The role of faint galaxies in reionizing the universe is still much-discussed, but there is no doubt that such galaxies contribute greatly to the UV ionizing flux, as shown by deep luminosity function studies. Together Hubble and Spitzer have also established the stellar-mass buildup over 97% of cosmic history. Yet some of the greatest surprises have come from the discovery of very luminous galaxies at z~8-11, around 400-650 million years after the Big Bang. Spectroscopic followup by Keck of some of these very rare, bright galaxies has confirmed redshifts from z~7 to z~9, and revealed, surprisingly, strong Lyα emission near the peak of reionization when the HI fraction in the IGM is high. The recent confirmation of a z=11.1 galaxy, just 400 million years after the Big Bang, by a combination of Hubble and Spitzer data, moved Hubble into JWST territory

  17. 基于EDS的煤中微细粒矿物相分布研究%Research on phase distribution of coal fine minerals based on energy disperse spectroscopy

    Institute of Scientific and Technical Information of China (English)

    于冰; 卢兆林; 王帅; 王震威; 于建勇

    2013-01-01

    Fine minerals mostly distribute in the organism of coal in the form of particulate,dissemination and irregular fine granular.The difficulty of mineral phase analysis,mineral formation time and the relation of organic matter are closely related to each other.The premise of selecting and establishing the analysis method is to divide the mineral phase boundaries.This paper presents a method which quantitatively combines low vaccum secondary electron image of scanning electron microscope (SEM),backscattered electron image technology and surface distribution and phase distribution of energy disperse spectroscopy (EDS) to assay the composition of the different micro fine granular minerals,phase distribution and the relationship of coal organic matter.The feasibility of distinguishing the type of clay minerals according to the relative content of major oxides in coal is analyzed.%煤中微细粒矿物大多数以微粒状、浸染状或不规则状细粒分布于有机基体中,矿物的相分析难度与矿物质形成时间以及与有机质的形成关系密切相关,能够准确划分矿物相的相界是选择和建立分析方法的前提.本文提出了一种采用扫描电镜(SEM)低真空二次电子像技术、背散射电子像技术结合能谱仪(EDS)面分布、相分布技术相结合的方法,来定量测定煤中不同微细粒矿物的组成、相分布以及与煤有机质的结构关系;分析了依据EDS获取粘土矿物主要氧化物相对含量数据来判别粘土矿物类型的可行性.

  18. Optical Coating Performance and Thermal Structure Design for Heat Reflectors of JWST Electronic Control Unit

    Science.gov (United States)

    Quijada, Manuel A.; Threat, Felix; Garrison, Matt; Perrygo, Chuck; Bousquet, Robert; Rashford, Robert

    2008-01-01

    The James Webb Space Telescope (JWST) consists of an infrared-optimized Optical Telescope Element (OTE) that is cooled down to 40 degrees Kelvin. A second adjacent component to the OTE is the Integrated Science Instrument Module, or ISIM. This module includes the electronic compartment, which provides the mounting surfaces and ambient thermally controlled environment for the instrument control electronics. Dissipating the 200 watts generated from the ISIM structure away from the OTE is of paramount importance so that the spacecraft's own heat does not interfere with the infrared light detected from distant cosmic sources. This technical challenge is overcome by a thermal subsystem unit that provides passive cooling to the ISIM control electronics. The proposed design of this thermal radiator consists of a lightweight structure made out of composite materials and low-emittance metal coatings. In this paper, we will present characterizations of the coating emittance, bidirectional reflectance, and mechanical structure design that will affect the performance of this passive cooling system.

  19. Slitless spectroscopy with the James Webb Space Telescope Near-Infrared Camera (JWST NIRCam)

    CERN Document Server

    Greene, Thomas P; Egami, Eiichi; Hodapp, Klaus W; Kelly, Douglas M; Leisenring, Jarron; Rieke, Marcia; Robberto, Massimo; Schlawin, Everett; Stansberry, John

    2016-01-01

    The James Webb Space Telescope near-infrared camera (JWST NIRCam) has two 2.'2 $\\times$ 2.'2 fields of view that are capable of either imaging or spectroscopic observations. Either of two $R \\sim 1500$ grisms with orthogonal dispersion directions can be used for slitless spectroscopy over $\\lambda = 2.4 - 5.0$ $\\mu$m in each module, and shorter wavelength observations of the same fields can be obtained simultaneously. We present the latest predicted grism sensitivities, saturation limits, resolving power, and wavelength coverage values based on component measurements, instrument tests, and end-to-end modeling. Short wavelength (0.6 -- 2.3 $\\mu$m) imaging observations of the 2.4 -- 5.0 $\\mu$m spectroscopic field can be performed in one of several different filter bands, either in-focus or defocused via weak lenses internal to NIRCam. Alternatively, the possibility of 1.0 -- 2.0 $\\mu$m spectroscopy (simultaneously with 2.4 -- 5.0 $\\mu$m) using dispersed Hartmann sensors (DHSs) is being explored. The grisms, wea...

  20. A model-based approach to the spatial and spectral calibration of NIRSpec onboard JWST

    CERN Document Server

    Dorner, Bernhard; Ferruit, Pierre; de Oliveira, Catarina Alves; Birkmann, Stephan M; Böker, Torsten; De Marchi, Guido; Gnata, Xavier; Köhler, Jess; Sirianni, Marco; Jakobsen, Peter

    2016-01-01

    Context: The NIRSpec instrument for the James Webb Space Telescope (JWST) can be operated in multiobject (MOS), long-slit, and integral field (IFU) mode with spectral resolutions from 100 to 2700. Its MOS mode uses about a quarter of a million individually addressable minislits for object selection, covering a field of view of $\\sim$9 $\\mathrm{arcmin}^2$. Aims: The pipeline used to extract wavelength-calibrated spectra from NIRSpec detector images relies heavily on a model of NIRSpec optical geometry. We demonstrate how dedicated calibration data from a small subset of NIRSpec modes and apertures can be used to optimize this parametric model to the necessary levels of fidelity. Methods: Following an iterative procedure, the initial fiducial values of the model parameters are manually adjusted and then automatically optimized, so that the model predicted location of the images and spectral lines from the fixed slits, the IFU, and a small subset of the MOS apertures matches their measured location in the main o...

  1. Status of the JWST/MIRI Focal Plane System and Cooler

    Science.gov (United States)

    Ressler, Michael E.; Goodson, G. B.; Khorrami, M. A.; Larson, M. E.; Mahoney, J. C.; Sukhatme, K. G.

    2009-01-01

    The Mid-Infrared Instrument (MIRI) is a multipurpose imager, coronagraph, and spectrometer for the James Webb Space Telescope. It provides wavelength coverage from 5 through 28 microns and is an integral contributor to all four of JWST's primary science themes. MIRI is being developed as a partnership between NASA and ESA, with JPL providing the Focal Plane System (FPS, consisting of the detectors, control electronics, and flight software) and the cooler, and a consortium of European astronomical institutes providing the optical bench and structure. The flight FPS is being prepared for delivery to the European Consortium for its integration into the optical bench, while the cooler is nearing its Critical Design Review. We describe the capabilities of the FPS and cooler, present test results and the predicted sensitivity performance of the FPS, and update the current status of each these systems. The research described in this poster was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  2. Alignment Test Results of the JWST Pathfinder Telescope Mirrors in the Cryogenic Environment

    Science.gov (United States)

    Whitman, Tony L.; Wells, Conrad; Hadaway, James; Knight, J. Scott; Lunt, Sharon

    2016-01-01

    After integration of the Optical Telescope Element (OTE) to the Integrated Science Instrument Module (ISIM) to become the OTIS, the James Webb Space Telescope OTIS is tested at NASAs Johnson Space Center (JSC) in the cryogenic vacuum Chamber A for alignment and optical performance. The alignment of the mirrors comprises a sequence of steps as follows: The mirrors are coarsely aligned using photogrammetry cameras with reflective targets attached to the sides of the mirrors. Then a multi-wavelength interferometer is aligned to the 18-segment primary mirror using cameras at the center of curvature to align reflected light from the segments and using fiducials at the edge of the primary mirror. Once the interferometer is aligned, the 18 primary mirror segments are then adjusted to optimize wavefront error of the aggregate mirror. This process phases the piston and tilt positions of all the mirror segments. An optical fiber placed at the Cassegrain focus of the telescope then emits light towards the secondary mirror to create a collimated beam emitting from the primary mirror. Portions of the collimated beam are retro-reflected from flat mirrors at the top of the chamber to pass through the telescope to the SI detector. The image on the detector is used for fine alignment of the secondary mirror and a check of the primary mirror alignment using many of the same analysis techniques used in the on-orbit alignment. The entire process was practiced and evaluated in 2015 at cryogenic temperature with the Pathfinder telescope.

  3. Alignment test results of the JWST Pathfinder Telescope mirrors in the cryogenic environment

    Science.gov (United States)

    Whitman, Tony L.; Wells, Conrad; Hadaway, James B.; Knight, J. Scott; Lunt, Sharon

    2016-07-01

    After integration of the Optical Telescope Element (OTE) to the Integrated Science Instrument Module (ISIM) to become the OTIS, the James Webb Space Telescope OTIS is tested at NASA's Johnson Space Center (JSC) in the cryogenic vacuum Chamber A for alignment and optical performance. The alignment of the mirrors comprises a sequence of steps as follows: The mirrors are coarsely aligned using photogrammetry cameras with reflective targets attached to the sides of the mirrors. Then a multi-wavelength interferometer is aligned to the 18-segment primary mirror using cameras at the center of curvature to align reflected light from the segments and using fiducials at the edge of the primary mirror. Once the interferometer is aligned, the 18 primary mirror segments are then adjusted to optimize wavefront error of the aggregate mirror. This process phases the piston and tilt positions of all the mirror segments. An optical fiber placed at the Cassegrain focus of the telescope then emits light towards the secondary mirror to create a collimated beam emitting from the primary mirror. Portions of the collimated beam are retro-reflected from flat mirrors at the top of the chamber to pass through the telescope to the Science Instrument (SI) detector. The image on the detector is used for fine alignment of the secondary mirror and a check of the primary mirror alignment using many of the same analysis techniques used in the on-orbit alignment. The entire process was practiced and evaluated in 2015 at cryogenic temperature with the Pathfinder telescope.

  4. A model-based approach to the spatial and spectral calibration of NIRSpec onboard JWST

    Science.gov (United States)

    Dorner, B.; Giardino, G.; Ferruit, P.; Alves de Oliveira, C.; Birkmann, S. M.; Böker, T.; De Marchi, G.; Gnata, X.; Köhler, J.; Sirianni, M.; Jakobsen, P.

    2016-08-01

    Context. The NIRSpec instrument for the James Webb Space Telescope (JWST) can be operated in multiobject spectroscopy (MOS), long-slit, and integral field unit (IFU) mode with spectral resolutions from 100 to 2700. Its MOS mode uses about a quarter of a million individually addressable minislits for object selection, covering a field of view of ~9 arcmin2. Aims: The pipeline used to extract wavelength-calibrated spectra from NIRSpec detector images relies heavily on a model of NIRSpec optical geometry. We demonstrate how dedicated calibration data from a small subset of NIRSpec modes and apertures can be used to optimize this parametric model to the necessary levels of fidelity. Methods: Following an iterative procedure, the initial fiducial values of the model parameters are manually adjusted and then automatically optimized, so that the model predicted location of the images and spectral lines from the fixed slits, the IFU, and a small subset of the MOS apertures matches their measured location in the main optical planes of the instrument. Results: The NIRSpec parametric model is able to reproduce the spatial and spectral position of the input spectra with high fidelity. The intrinsic accuracy (1-sigma, rms) of the model, as measured from the extracted calibration spectra, is better than 1/10 of a pixel along the spatial direction and better than 1/20 of a resolution element in the spectral direction for all of the grating-based spectral modes. This is fully consistent with the corresponding allocation in the spatial and spectral calibration budgets of NIRSpec.

  5. The Impact of JWST Broadband Filter Choice on Photometric Redshift Estimation

    Science.gov (United States)

    Bisigello, L.; Caputi, K. I.; Colina, L.; Le Fèvre, O.; Nørgaard-Nielsen, H. U.; Pérez-González, P. G.; Pye, J.; van der Werf, P.; Ilbert, O.; Grogin, N.; Koekemoer, A.

    2016-12-01

    The determination of galaxy redshifts in the James Webb Space Telescope’s (JWST) blank-field surveys will mostly rely on photometric estimates, based on the data provided by JWST’s Near-Infrared Camera (NIRCam) at 0.6-5.0 μm and Mid Infrared Instrument (MIRI) at λ \\gt 5.0 μ {{m}}. In this work we analyze the impact of choosing different combinations of NIRCam and MIRI broadband filters (F070W to F770W), as well as having ancillary data at λ \\lt 0.6 μ {{m}}, on the derived photometric redshifts (z phot) of a total of 5921 real and simulated galaxies, with known input redshifts z = 0-10. We found that observations at λ \\lt 0.6 μ {{m}} are necessary to control the contamination of high-z samples by low-z interlopers. Adding MIRI (F560W and F770W) photometry to the NIRCam data mitigates the absence of ancillary observations at λ \\lt 0.6 μ {{m}} and improves the redshift estimation. At z = 7-10, accurate z phot can be obtained with the NIRCam broadbands alone when {{S}}/{{N}}≥slant 10, but the z phot quality significantly degrades at {{S}}/{{N}}≤slant 5. Adding MIRI photometry with 1 mag brighter depth than the NIRCam depth allows for a redshift recovery of 83%-99%, depending on spectral energy distribution type, and its effect is particularly noteworthy for galaxies with nebular emission. The vast majority of NIRCam galaxies with [F150W] = 29 AB mag at z = 7-10 will be detected with MIRI at [F560W, F770W] \\lt 28 mag if these sources are at least mildly evolved or have spectra with emission lines boosting the mid-infrared fluxes.

  6. Mossbauer Effect Study of the Hyper fine Structure of the Different Phases of Iron in the Portland Cement Produced in Qatar

    OpenAIRE

    Eissa, N. A. [نبيل عيسى; Sallam, H. A.; Al-Houty, L.; Al-Mauraikhy, M.

    1981-01-01

    Various samples of the raw materials used in the manufacture of Portland cement in Qatar, the clinker produced and the cement itself were studied by using Mossbauer Effect and X-ray diffraction analysis in order to investigate the hyperfine structure of the iron forms present and the distribution of these forms among the different phases of the cement. The results obtained revealed the presence of five forms of iron in the cement clinker (a) Fe3"1" ions in octahedral sites existed in the ferr...

  7. The spectral calibration of JWST/NIRSpec: results from the recent cryo-vacuum campaign (ISIM-CV3)

    Science.gov (United States)

    Giardino, Giovanna; Luetzgendorf, Nora; Ferruit, Pierre; Dorner, Bernhard; Alves de Oliveira, Catarina; Birkmann, Stephan M.; Boeker, Torsten; Rawle, Tim; Sirianni, Marco

    2016-07-01

    The NIRSpec instrument of JWST can be operated in multi-object (MOS), long-slit, and integral field mode with spectral resolutions from 100 to 2700. Its MOS mode uses about a quarter of a million individually addressable mini-slits for object selection, covering a field of view of 9 square-arcminute. We have developed a procedure to optimize a parametric model of the instrument that provides the basis for the extraction of wavelength calibrated spectra from NIRSpec data, from any of the apertures and for all the modes. Here, we summarize the steps undertaken to optimize the instrument model parameters using the data acquired during the latest cryo-vacuum campaign of the JWST Integrated Science Instrument Module, recently carried out at NASA Goddard Space Flight Center. The calibrated parametric model is able to reproduce the spatial and spectral position of the input spectra with an intrinsic accuracy (1-sigma, RMS) ~ 1/10 of a pixel in spatial and spectral direction for all the modes. The overall wavelength calibration accuracy (RMS) of the model as measured on the extracted spectra is better than 1/20 of a resolution element for all of the grating-based spectral modes and at the level of 1/14 of a resolution element for the prism. These results are well within the allocations for the model in the overall spatial and spectral calibration budget of NIRSpec.

  8. James Webb Space Telescope (JWST) Integrated Science Instruments Module (ISIM) Cryo-Vacuum (CV) Test at GSFC

    Science.gov (United States)

    Yew, Calinda M.

    2014-01-01

    JWST ISIM has entered into its system-level testing program at NASA Goddard Space Flight Center (GSFC). In December 2013, ISIM successfully completed the first in a series of three cryo-vacuum tests, which included two flight science instruments. Since then, there have been full-fledged efforts towards the CV2 test scheduled to finish at the end of 2014. The complexity of the mission has generated challenging requirements that demand highly reliable system performance and capabilities from the Space Environment Simulator (SES) vacuum chamber. In order to satisfy the program requirements, GSFC had to develop unique structural and thermal hardware to test ISIM. Most noteworthy is a helium shroud structure and cooling system built in order to achieve operational temperatures below 20K (-253C). This paper: (1) provides an overview of the integrated mechanical and thermal facility systems required to achieve the objectives of JWST ISIM testing, (2) communicates the performance and challenges of the SES during the first ISIM test, and (3) summarizes the action plan to improve the system prior to the next test.

  9. Measuring segmented primary mirror WFE in the presence of vibration and thermal drift on the light-weighted JWST

    Science.gov (United States)

    Whitman, Tony L.; Dziak, Kenneth J.; Wells, Conrad; Olczak, Gene

    2012-09-01

    The light-weighted design of the Optical Telescope Element (OTE) of the James Webb Telescope (JWST) leads to additional sensitivity to vibration from the ground - an important consideration to the measurement uncertainty of the wavefront error (WFE) in the primary mirror. Furthermore, segmentation of the primary mirror leads to rigid-body movements of segment areas in the WFE. The ground vibrations are minimized with modifications to the test facility, and by the architecture of the equipment supporting the load. Additional special test equipment (including strategically placed isolators, tunable mass dampers, and cryogenic magnetic dampers) mitigates the vibration and the response sensitivity before reaching the telescope. A multi-wavelength interferometer is designed and operated to accommodate the predicted residual vibration. Thermal drift also adds to the measurement variation. Test results of test equipment components, measurement theory, and finite element analysis combine to predict the test uncertainty in the future measurement of the primary mirror. The vibration input to the finite element model comes from accelerometer measurements of the facility with the environmental control pumps operating. One of the isolators have been built and tested to validate the dynamic performance. A preliminary model of the load support equipment and the OTE with the Integrated Science Instrument Module (ISIM) is complete. The performance of the add-on dampers have been established in previous applications. And operation of the multi-wavelength interferometer was demonstrated on a scaled hardware version of the JWST in an environment with vibration and thermal drift.

  10. A new HST/Herschel deep field at the North Ecliptic Pole: preparing the way for JWST, SPICA and Euclid

    CERN Document Server

    Serjeant, Stephen; Burgarella, Denis; Clements, Dave; De Zotti, Gianfranco; Goto, Tomo; Hatsukade, Bunyo; Hopwood, Rosalind; Hwang, Narae; Inami, Hanae; Jeong, Woong-Seob; Kim, Seong Jin; Krumpe, Mirko; Lee, Myung Gyoon; Malkan, Matt; Matsuhara, Hideo; Miyaji, Takamitsu; Oyabu, Shinki; Pearson, Chris; Takeuchi, Tsutomu; Vaccari, Mattia; Valtchanov, Ivan; van der Werf, Paul; Wada, Takehiko; White, Glenn

    2012-01-01

    We propose a co-ordinated multi-observatory survey at the North Ecliptic Pole. This field is the natural extragalactic deep field location for most space observatories (e.g. containing the deepest Planck, WISE and eROSITA data), is in the continuous viewing zones for e.g. Herschel, HST, JWST, and is a natural high-visibility field for the L2 halo orbit of SPICA with deep and wide-field legacy surveys already planned. The field is also a likely deep survey location for the forthcoming Euclid mission. It is already a multi-wavelength legacy field in its own right (e.g. AKARI, LOFAR, SCUBA-2): the outstanding and unparalleled continuous mid-IR photometric coverage in this field and nowhere else enables a wide range of galaxy evolution diagnostics unachievable in any other survey field, by spanning the wavelengths of redshifted PAH and silicate features and the peak energy output of AGN hot dust. We argue from the science needs of Euclid and JWST, and from the comparative multiwavelength depths, that the logical ...

  11. The accretion/ejection paradigm in young stellar objects: from HST and Herschel to JWST

    Science.gov (United States)

    Podio, Linda

    2012-07-01

    Stellar jets and molecular outflows are observed in association with young accreting stars and are believed to play a key role in the star formation process. In this talk I will show how current and future space missions are of crucial importance to investigate the origin of stellar jets and their link to the accretion process. Thanks to its high angular (˜0.1") resolution, HST has been the first telescope allowing us to investigate the jet physics at optical/UV wavelengths down to the heart of the launching mechanism. We recently analysed a datacube of the jet emitted by the T Tauri star DG Tau obtaining spatio-kinematical maps of the hot atomic gas in the jet and of its physical conditions (Maurri et al., submitted). These data confirm the predictions of theoretical models including the fact that jets may extract the excess angular momentum from the system. In the last two years Herschel has further improved our comprehension of the ejection process observing the far infrared counterpart of fast and collimated atomic jets. PACS and HIFI observations, acquired within the GASPS (GAS in Protoplanetary Systems) Open Time Key Project (PI: B. Dent), show that T Tauri stars driving optical jets are also associated with a warm gas component emitting not only atomic ([OI], [CII]) but also molecular (high-J CO, H_2O, OH) lines. The comparison with Class 0 outflows highlights a clear evolutionary trend: the emission associated with evolved Class I/II sources is fainter and more compact and the estimated mass loss rates and lines cooling are one to two orders of magnitudes lower (Podio et al., to be submitted). The arrival of JWST will fill-in the gap between HST and Herschel opening a new window in the near and mid-infrared range at unprecedented angular resolution (down to 0.03"). This will allow resolving the emission in both atomic (e.g., [FeII]) and molecular (e.g., H_2) lines and understanding if the molecular gas is entrained by the atomic jet or launched with it

  12. Near-edge x-ray absorption fine-structure study of ion-beam-induced phase transformation in Gd2(Ti1-yZry)2O7

    Science.gov (United States)

    Nachimuthu, P.; Thevuthasan, S.; Shutthanandan, V.; Adams, E. M.; Weber, W. J.; Begg, B. D.; Shuh, D. K.; Lindle, D. W.; Gullikson, E. M.; Perera, R. C. C.

    2005-02-01

    The structural and electronic properties of Gd2(Ti1-yZry)2O7 (y =0-1) pyrochlores following a 2.0-MeV Au2+ ion-beam irradiation (˜5.0×1014Au2+/cm2) have been investigated by Ti2p and O1s near-edge x-ray absorption fine structure (NEXAFS). The irradiation of Gd2(Ti1-yZry)2O7 leads to the phase transformation from the ordered pyrochlore structure (Fd3m) to the defect fluorite structure (Fm3m) regardless of Zr concentration. Irradiated Gd2(Ti1-yZry)2O7 with y ⩽0.5 are amorphous, although significant short-range order is present. Contrasting to this behavior, compositions with y ⩾0.75 retain crystallinity in the defect fluorite structure following irradiation. The local structures of Zr4+ in the irradiated Gd2(Ti1-yZry)2O7 with y ⩾0.75 determined by NEXAFS are the same as in the cubic fluorite-structured yttria-stabilized zirconia (Y -ZrO2), thereby providing conclusive evidence for the phase transformation. The TiO6 octahedra present in Gd2(Ti1-yZry)2O7 are completely modified by ion-beam irradiation to TiOx polyhedra, and the Ti coordination is increased to eight with longer Ti -O bond distances. The similarity between cation sites and the degree of disorder in Gd2Zr2O7 facilitate the rearrangement and relaxation of Gd, Zr, and O ions/defects. This inhibits amorphization during the ion-beam-induced phase transition to the radiation-resistant defect fluorite structure, which is in contrast to the ordered Gd2Ti2O7.

  13. Fine structure of charge exchange lines observed in laboratory plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ida, K.; Nishimura, S. [National Inst. for Fusion Science, Nagoya (Japan); Kondo, K.

    1997-01-01

    The influence of the fine structure of charge exchange lines appears only at the plasma edge or in the recombining phase where the ion temperature is low enough. The observed spectra in Li III and C VI are consistent with the sum of fine-structure components populated by statistical weights (assuming complete l-mixing) not by direct charge exchange cross sections. Some discrepancy was observed in the intensity ratio of fine-structure components between the observation and calculation for C VI in the recombining phase. The fine-structure of charge exchange lines gives an apparent Doppler shift in plasma rotation velocity measurement using charge exchange spectroscopy. (author)

  14. Fine Arts Database (FAD)

    Data.gov (United States)

    General Services Administration — The Fine Arts Database records information on federally owned art in the control of the GSA; this includes the location, current condition and information on artists.

  15. Fine Needle Aspiration

    Science.gov (United States)

    ... FNA), also called fine needle biopsy, is a type of biopsy that can be used to diagnose many types ... in which case another FNA or a different type of biopsy procedure may needed. Because the needle is so ...

  16. Analyses of fine paste ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sabloff, J A [ed.

    1980-01-01

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics. (DLC)

  17. Transport of reservoir fines

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander; Stenby, Erling Halfdan

    Modeling transport of reservoir fines is of great importance for evaluating the damage of production wells and infectivity decline. The conventional methodology accounts for neither the formation heterogeneity around the wells nor the reservoir fines’ heterogeneity. We have developed an integral...... dispersion equation in modeling the transport and the deposition of reservoir fines. It successfully predicts the unsymmetrical concentration profiles and the hyperexponential deposition in experiments....

  18. High-precision cryogenic wheel mechanisms of the JWST/MIRI instrument: performance of the flight models

    Science.gov (United States)

    Krause, O.; Müller, F.; Birkmann, S.; Böhm, A.; Ebert, M.; Grözinger, U.; Henning, Th.; Hofferbert, R.; Huber, A.; Lemke, D.; Rohloff, R.-R.; Scheithauer, S.; Gross, T.; Fischer, T.; Luichtel, G.; Merkle, H.; Übele, M.; Wieland, H.-U.; Amiaux, J.; Jager, R.; Glauser, A.; Parr-Burman, P.; Sykes, J.

    2010-07-01

    The Mid Infrared Instrument (MIRI) aboard JWST is equipped with one filter wheel and two dichroic-grating wheel mechanisms to reconfigure the instrument between observing modes such as broad/narrow-band imaging, coronagraphy and low/medium resolution spectroscopy. Key requirements for the three mechanisms with up to 18 optical elements on the wheel include: (1) reliable operation at T = 7 K, (2) high positional accuracy of 4 arcsec, (3) low power dissipation, (4) high vibration capability, (5) functionality at 7 K ball bearing, a central torque motor for actuation, a ratchet system with monolithic CuBe flexural pivots for precise and powerless positioning and a magnetoresistive position sensor has been implemented. We report here the final performance and lessons-learnt from the successful acceptance test program of the MIRI wheel mechanism flight models. The mechanisms have been meanwhile integrated into the flight model of the MIRI instrument, ready for launch in 2014 by an Ariane 5 rocket.

  19. Which fine-tuning arguments are fine?

    CERN Document Server

    Grinbaum, Alexei

    2009-01-01

    The argument from naturalness is widely employed in contemporary quantum field theory. Essentially a formalized aesthetic criterion, it received a meaning in the debate on the Higgs mechanism, which goes beyond aesthetics. We follow the history of technical definitions of fine tuning at the scale of electroweak symmetry breaking. It is argued that they give rise to a special interpretation of probability, which we call Gedankenfrequency. By extension of its original meaning, the argument from naturalness is used to compare different models beyond the Standard Model. We show that in this case naturalness cannot be defined objectively. Rather, it functions as socio-historical heuristics in particle physics and it contributes to the advent of a probabilistic version of Popper's falsificationism.

  20. Fine 5 lavastab Venemaal

    Index Scriptorium Estoniae

    2013-01-01

    Tantsuteatru Fine 5 koreograafid Tiina Ollesk ja Rene Nõmmik toovad Jekaterinburgis välja lavastuse "... and Red", esitajaks Venemaa nimekas nüüdistantsutrupp Provintsialnõje Tantsõ. Lavastuses kõlab Taavo Remmeli kontrabassiimprovisatsioon "12.12.2006"

  1. A fine art

    Energy Technology Data Exchange (ETDEWEB)

    Schnabel, G.; Raaff, T. [Andritz AG (Austria)

    2006-07-15

    The paper describes a new dewatering system for coal fines which challenges established processes by using screenbowl centrifuge and hyperbaric filter combinations. Company acquisitions over the past three to four years enabled Andritz AG to develop a new system combining two technologies. The article describes the benefits of the combination process and explains the basic operation of these machines. 4 figs.

  2. The Fine Dutch Tradition

    NARCIS (Netherlands)

    Hooimeijer, F.L.

    2012-01-01

    Publication of the exhibition and symposium on water adaptive urban planning and architecture in Bangkok. The Urban Fine Dutch Tradition is a dynamic tradition of making urban designs using the parameters of the natural system – incorperating in an efficient way the hydrological cycle, the soil and

  3. Imeilus Fine 5

    Index Scriptorium Estoniae

    2017-01-01

    Vaba Lava teatrikeskuse laval esineb Fine 5 oma lavastusega "Imeilus". Tiina Ollesk ja Renee Nõmmik, tantsulavastuse autorid on koreograafid, õppejõud, lavastajad ja kogemustega tantsijad. 29. jaanuaril korraldavad Tiina Ollesk ja Renee Nõmmik Tallinna Ülikoolis kaasaegse liikumismõtlemise töötoa, mis on pühendatud lavastusele "Imeilus"

  4. Fine 5 lavastab Venemaal

    Index Scriptorium Estoniae

    2013-01-01

    Tantsuteatru Fine 5 koreograafid Tiina Ollesk ja Rene Nõmmik toovad Jekaterinburgis välja lavastuse "... and Red", esitajaks Venemaa nimekas nüüdistantsutrupp Provintsialnõje Tantsõ. Lavastuses kõlab Taavo Remmeli kontrabassiimprovisatsioon "12.12.2006"

  5. Preservation of Thermal Control Specular Gold Baffle Surface on the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Electronics Compartment (IEC)

    Science.gov (United States)

    MonteedeGarcia, Kristina; Patel, Jignasha; Perry, Radford, III

    2010-01-01

    Extremely tight thermal control property degradation allowances on the vapor-deposited, gold-coated IEC baffle surface, made necessary by the cryogenic JWST Observatory operations, dictate tight contamination requirements on adjacent surfaces. Theoretical degradation in emittance with contaminant thickness was calculated. Maximum allowable source outgassing rates were calculated using worst case view factors from source to baffle surface. Tight requirements pushed the team to change the design of the adjacent surfaces to minimize the outgassing sources

  6. Fine Water Mist Fire Extinguisher for Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This three phase SBIR project from ADA Technologies Inc. (ADA) builds upon the experience of ADA in development of fine water mist (FWM) fire suppression technology....

  7. Towards Precise Constraints on the Chemical Compositions and Thermal Structures of Giant Exoplanets with a JWST GTO Program

    Science.gov (United States)

    Bean, Jacob; Lunine, Jonathan I.

    2017-06-01

    The chemical compositions and thermal structures of close-in planets are two of the major questions raised over the last 15+ years of exoplanet atmospheric characterization. These are fundamental questions in their own right, and answering them also has the potential to improve our understanding of the planets in the Solar System. JWST offers the opportunity to make a major advance on these topics by revealing a more complete and accurate inventory of the chemical species in exoplanet atmospheres and by precisely measuring atmospheric temperatures over a broad range of pressures. I will describe how we plan to use an Interdisciplinary Scientist GTO program to determine the compositions and thermal structures of transiting, hot giant exoplanets using dayside thermal emission measurements obtained at secondary eclipse. Our composition measurements are focused on determining absolute molecular abundances as a tracer of atmospheric metallicity and the abundance ratio of carbon to oxygen. The targets in our program have a range of masses and irradiation, which will enable us to test theories of how atmospheric metallicity varies with planet mass and how thermal structures respond to different levels of stellar forcing.

  8. Very fine Twilights

    Science.gov (United States)

    Boico, Vladimir

    1992-04-01

    The author is describing a very fine twilight on 3 January 1992 at 17 h25 m LT (The Sunset was at 16h48m LT) of red - terracotta color. The author is relating this twilight with the volcanic erruption of Pinatubo on the Philipines islands from June 1991. The author is describing the following phenomena related with Volcanic erruption: twilights, the greenish of the Moon's surface, a change in the color of Day Sky to white, Haloes around the Sun. The author is pointing out, that the phenomena mentioned could prolonge in time 2 or 3 years.

  9. Characterization of DPOAE fine structure

    DEFF Research Database (Denmark)

    Reuter, Karen; Hammershøi, Dorte

    2005-01-01

    , and has recently been demonstrated to exist in low level equal-loudness contours. The character of the DPOAE fine structure depends on several parameters, i.e., level, frequencies, and frequency of the two primaries, but also level and character of the noise floor. The prevalence and character of the fine......The distortion product otoacoustic emission (DPOAE) fine structure is revealed, when measuring DPOAE with a very fine frequency resolution. It is characterized by consistent maxima and minima with notches of up to 20 dB depth. The fine structure is known also from absolute hearing thresholds...... structures are highly individual, and till now no standardized method has been suggested for a consistent categorization. In the present paper a method developed for the categorization of fine structures is presented. The method has been used in two previous studies on the prevalence of fine structures, 1...

  10. Wavefront-Error Performance Characterization for the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Science Instruments

    Science.gov (United States)

    Aronstein, David L.; Smith, J. Scott; Zielinski, Thomas P.; Telfer, Randal; Tournois, Severine C.; Moore, Dustin B.; Fienup, James R.

    2016-01-01

    The science instruments (SIs) comprising the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) were tested in three cryogenic-vacuum test campaigns in the NASA Goddard Space Flight Center (GSFC)'s Space Environment Simulator (SES) test chamber. In this paper, we describe the results of optical wavefront-error performance characterization of the SIs. The wavefront error is determined using image-based wavefront sensing, and the primary data used by this process are focus sweeps, a series of images recorded by the instrument under test in its as-used configuration, in which the focal plane is systematically changed from one image to the next. High-precision determination of the wavefront error also requires several sources of secondary data, including 1) spectrum, apodization, and wavefront-error characterization of the optical ground-support equipment (OGSE) illumination module, called the OTE Simulator (OSIM), 2) F-number and pupil-distortion measurements made using a pseudo-nonredundant mask (PNRM), and 3) pupil geometry predictions as a function of SI and field point, which are complicated because of a tricontagon-shaped outer perimeter and small holes that appear in the exit pupil due to the way that different light sources are injected into the optical path by the OGSE. One set of wavefront-error tests, for the coronagraphic channel of the Near-Infrared Camera (NIRCam) Longwave instruments, was performed using data from transverse translation diversity sweeps instead of focus sweeps, in which a sub-aperture is translated and/or rotated across the exit pupil of the system. Several optical-performance requirements that were verified during this ISIM-level testing are levied on the uncertainties of various wavefront-error-related quantities rather than on the wavefront errors themselves. This paper also describes the methodology, based on Monte Carlo simulations of the wavefront-sensing analysis of focus-sweep data, used to establish

  11. Granulation of fine powder

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ching-Fong

    2016-08-09

    A mixture of fine powder including thorium oxide was converted to granulated powder by forming a first-green-body and heat treating the first-green-body at a high temperature to strengthen the first-green-body followed by granulation by crushing or milling the heat-treated first-green-body. The granulated powder was achieved by screening through a combination of sieves to achieve the desired granule size distribution. The granulated powder relies on the thermal bonding to maintain its shape and structure. The granulated powder contains no organic binder and can be stored in a radioactive or other extreme environment. The granulated powder was pressed and sintered to form a dense compact with a higher density and more uniform pore size distribution.

  12. EMC Testing on the Integrated Science Instrument Module (ISIM) - A Summary of the EMC Test Campaign for the Science Payload of the James Webb Space Telescope (JWST)

    Science.gov (United States)

    McCloskey, John

    2016-01-01

    This paper describes the electromagnetic compatibility (EMC) tests performed on the Integrated Science Instrument Module (ISIM), the science payload of the James Webb Space Telescope (JWST), at NASAs Goddard Space Flight Center (GSFC) in August 2015. By its very nature of being an integrated payload, it could be treated as neither a unit level test nor an integrated spacecraft/observatory test. Non-standard test criteria are described along with non-standard test methods that had to be developed in order to evaluate them. Results are presented to demonstrate that all test criteria were met in less than the time allocated.

  13. Structure and properties of advanced fine grained steels produced using novel thermal treatments

    OpenAIRE

    Vuorinen, Esa

    2012-01-01

    Fine grained advanced steels exhibit favourable mechanical properties for applications requiring high strength, ductility and impact toughness. These properties result from a microstructure containing a fine distribution of several phases including ferrite, austenite, martensite and bainite. The bainite phase is in the form of fine lamellas of ferrite and carbon-enriched austenite which due to proper control of the chemical composition is lacking the nanometre scaled carbides associated with ...

  14. Optical Modeling Activities for NASA's James Webb Space Telescope (JWST). 4; Overview and Introduction of Matlab Based Toolkits used to Interface with Optical Design Software

    Science.gov (United States)

    Howard, Joseph

    2007-01-01

    This is part four of a series on the ongoing optical modeling activities for James Webb Space Telescope (JWST). The first two discussed modeling JWST on-orbit performance using wavefront sensitivities to predict line of sight motion induced blur, and stability during thermal transients. The third investigates the aberrations resulting from alignment and figure compensation of the controllable degrees of freedom (primary and secondary mirrors), which may be encountered during ground alignment and on-orbit commissioning of the observatory. The work here introduces some of the math software tools used to perform the work of the previous three papers of this series. NASA has recently approved these in-house tools for public release as open source, so this presentation also serves as a quick tutorial on their use. The tools are collections of functions written in Matlab, which interface with optical design software (CodeV, OSLO, and Zemax) using either COM or DDE communication protocol. The functions are discussed, and examples are given.

  15. Fine-sized LiNi 0.8Co 0.15Mn 0.05O 2 cathode powders prepared by combined process of gas-phase reaction and solid-state reaction methods

    Science.gov (United States)

    Ju, Seo Hee; Kang, Yun Chan

    The Ni-rich precursor powders with spherical shape and filled morphologies were prepared by spray pyrolysis from the spray solution with citric acid, ethylene glycol and a drying control chemical additive. The precursor powders with controlled morphologies formed the LiNi 0.8Co 0.15Mn 0.05O 2 cathode powders with spherical shape and fine size by solid-state reaction with lithium hydroxide. However, the cathode powders prepared from the spray solution without additives had irregular morphologies and were large in size. The precursor powders with hollow and porous morphologies formed cathode powders with irregular and aggregated morphologies. The composition ratios of the nickel, cobalt and manganese components were maintained in the as-prepared, precursor and cathode powders. The initial discharge capacity of the LiNi 0.8Co 0.15Mn 0.05O 2 cathode powders with spherical shape and fine size tested at a temperature of 55 °C under a constant current density of 0.5 C was 215 mAh g -1. The discharge capacity of the LiNi 0.8Co 0.15Mn 0.05O 2 cathode powders decreased to 81% of the initial value after 30 cycles.

  16. Wavefront-error performance characterization for the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) science instruments

    Science.gov (United States)

    Aronstein, David L.; Smith, J. S.; Zielinski, Thomas P.; Telfer, Randal; Tournois, Severine C.; Moore, Dustin B.; Fienup, James R.

    2016-07-01

    The science instruments (SIs) comprising the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) were tested in three cryogenic-vacuum test campaigns in the NASA Goddard Space Flight Center (GSFC)'s Space Environment Simulator (SES) test chamber. In this paper, we describe the results of optical wavefront-error performance characterization of the SIs. The wavefront error is determined using image-based wavefront sensing, and the primary data used by this process are focus sweeps, a series of images recorded by the instrument under test in its as-used configuration, in which the focal plane is systematically changed from one image to the next. High-precision determination of the wavefront error also requires several sources of secondary data, including 1) spectrum, apodization, and wavefront-error characterization of the optical ground-support equipment (OGSE) illumination module, called the OTE Simulator (OSIM), 2) f/# and pupil-distortion measurements made using a pseudo-nonredundant mask (PNRM), and 3) pupil-geometry predictions for each SI field point tested, which are complicated because of a tricontagon-shaped outer perimeter and small holes that appear in the exit pupil due to the way that different light sources are injected into the optical path by the OGSE. One set of wavefront-error tests, for the coronagraphic channel of the Near-Infrared Camera (NIRCam) Longwave instruments, was performed using data from transverse-translation diversity (TTD) sweeps instead of focus sweeps, in which a subaperture is translated and/or rotated across the exit pupil of the system from one image to the next. Several optical-performance requirements that were verified during this ISIM Element-level testing are levied on the uncertainties of various wavefront-error-related quantities rather than on the wavefront errors themselves. This paper also gives an overview of the methodology, based on Monte Carlo simulations of the wavefront-sensing analysis

  17. Evaluation of hyperbaric filtration for fine coal dewatering. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Parekh, B.K. [Univ. of Kentucky, Lexington, KY (United States); Hogg, R. [Pennsylvania State Univ., University Park, PA (United States); Fonseca, A. [CONSOL Inc. (United States)

    1996-08-15

    The main objectives of the project were to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20% moisture. The program consisted of three phases, namely Phase 1 -- Model Development, Phase 2 -- Laboratory Studies, Phase 3 -- Pilot Plant Testing. The Pennsylvania State University led efforts in Phase 1, the University of Kentucky in Phase 2, and CONSOL Inc. in Phase 3 of the program. All three organizations were involved in all the three phases of the program. The Pennsylvania State University developed a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky conducted experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in Phase 1 and 2 were tested in two of the CONSOL Inc. coal preparation plants using an Andritz Ruthner portable hyperbaric filtration unit.

  18. Dark energy with fine redshift sampling

    Science.gov (United States)

    Linder, Eric V.

    2007-03-01

    The cosmological constant and many other possible origins for acceleration of the cosmic expansion possess variations in the dark energy properties slow on the Hubble time scale. Given that models with more rapid variation, or even phase transitions, are possible though, we examine the fineness in redshift with which cosmological probes can realistically be employed, and what constraints this could impose on dark energy behavior. In particular, we discuss various aspects of baryon acoustic oscillations, and their use to measure the Hubble parameter H(z). We find that currently considered cosmological probes have an innate resolution no finer than Δz≈0.2 0.3.

  19. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    Energy Technology Data Exchange (ETDEWEB)

    K. Osseo-Asare; X. Zeng

    2002-01-01

    The objective of this research project is to develop an aqueous biphase extraction process for the treatment of fine coals. Aqueous biphase extraction is an advanced separation technology that relies on the ability of an aqueous system consisting of a water-soluble polymer and another component, e.g., another polymer, an inorganic salt, or a nonionic surfactant, to separate into two immiscible aqueous phases. The principle behind the partition of solid particles in aqueous biphase systems is the physicochemical interaction between the solid surface and the surrounding liquid solution. In order to remove sulfur and mineral matter from fine coal with aqueous biphasic extraction, it is necessary to know the partitioning behavior of coal, as well as the inorganic mineral components. Therefore, in this research emphasis was placed on the partitioning behavior of fine coal particles as well as model fine inorganic particles in aqueous biphase systems.

  20. Nitramine Drying & Fine Grinding Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Nitramine Drying and Fine Grinding Facility provides TACOM-ARDEC with a state-of-the-art facility capable of drying and grinding high explosives (e.g., RDX and...

  1. Fine 5 kolib Kumu lavale

    Index Scriptorium Estoniae

    2006-01-01

    Kumu kunstimuuseumi auditooriumis toimub 21. veebruaril Fine 5 kaasaegse tantsu etendus "Panus". Esinevad Tiina Ollesk, Irina Pähn, žonglöör Dimitri Kruus, disainer Rain Saukas ja muusik Mattias Siitan

  2. Briquetting anthracite fines for recycle

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, S.; Price, J.J.

    1993-01-01

    A laboratory study of the briquetting of anthracite fines (recovered from a dryer) with pitch is reported, and a proposed plant flowsheet is discussed. The briquettes would be used with the coarser anthracite in electric furnace smelting of ilmenite.

  3. Fine 5 kolib Kumu lavale

    Index Scriptorium Estoniae

    2006-01-01

    Kumu kunstimuuseumi auditooriumis toimub 21. veebruaril Fine 5 kaasaegse tantsu etendus "Panus". Esinevad Tiina Ollesk, Irina Pähn, žonglöör Dimitri Kruus, disainer Rain Saukas ja muusik Mattias Siitan

  4. JWST and Exoplanets

    Science.gov (United States)

    Mather, John C.

    2009-01-01

    The James Webb Space Telescope is on track for a launch in 2013. The author reviews the status and progress on the key hardware. The first primary mirror segments are already at MSFC for cryogenic tests, the mid IR instrument (MIRI) has already had successful tests of the engineering model, and the detectors are showing excellent performance. The author also describes the scientific objectives of the mission, with emphasis on the predicted capabilities for observing planets by the transit technique and through direct imaging. Recent direct observations of planets by HST and by adaptive optics from the ground have shown that, under favorable circumstances, much can be learned.

  5. Communication Optimizations for Fine-Grained UPCApplications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Yu; Iancu, Costin; Yelick, Katherine

    2005-07-08

    Global address space languages like UPC exhibit high performance and portability on a broad class of shared and distributed memory parallel architectures. The most scalable applications use bulk memory copies rather than individual reads and writes to the shared space, but finer-grained sharing can be useful for scenarios such as dynamic load balancing, event signaling, and distributed hash tables. In this paper we present three optimization techniques for global address space programs with fine-grained communication: redundancy elimination, use of split-phase communication, and communication coalescing. Parallel UPC programs are analyzed using static single assignment form and a data flow graph, which are extended to handle the various shared and private pointer types that are available in UPC. The optimizations also take advantage of UPC's relaxed memory consistency model, which reduces the need for cross thread analysis. We demonstrate the effectiveness of the analysis and optimizations using several benchmarks, which were chosen to reflect the kinds of fine-grained, communication-intensive phases that exist in some larger applications. The optimizations show speedups of up to 70 percent on three parallel systems, which represent three different types of cluster network technologies.

  6. UAl2 : Fine structure of the f bands

    NARCIS (Netherlands)

    Groot, R.A. de; Koelling, D.D.; Weger, M.

    1985-01-01

    The electronic structure of the C15, or cubic-Laves-phase material, UAl2 has been calculated using the linearized relativistic augmented-plane-wave method. The anomalous behavior of the electrical resistivity, specific heat, and magnetic susceptibility can be explained by the fine structure of the

  7. Detecting Proxima b’s Atmosphere with JWST Targeting CO2 at 15 μm Using a High-pass Spectral Filtering Technique

    Science.gov (United States)

    Snellen, I. A. G.; Désert, J.-M.; Waters, L. B. F. M.; Robinson, T.; Meadows, V.; van Dishoeck, E. F.; Brandl, B. R.; Henning, T.; Bouwman, J.; Lahuis, F.; Min, M.; Lovis, C.; Dominik, C.; Van Eylen, V.; Sing, D.; Anglada-Escudé, G.; Birkby, J. L.; Brogi, M.

    2017-08-01

    Exoplanet Proxima b will be an important laboratory for the search for extraterrestrial life for the decades ahead. Here, we discuss the prospects of detecting carbon dioxide at 15 μm using a spectral filtering technique with the Medium Resolution Spectrograph (MRS) mode of the Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope (JWST). At superior conjunction, the planet is expected to show a contrast of up to 100 ppm with respect to the star. At a spectral resolving power of R = 1790-2640, about 100 spectral CO2 features are visible within the 13.2-15.8 μm (3B) band, which can be combined to boost the planet atmospheric signal by a factor of 3-4, depending on the atmospheric temperature structure and CO2 abundance. If atmospheric conditions are favorable (assuming an Earth-like atmosphere), with this new application to the cross-correlation technique, carbon dioxide can be detected within a few days of JWST observations. However, this can only be achieved if both the instrumental spectral response and the stellar spectrum can be determined to a relative precision of ≤1 × 10-4 between adjacent spectral channels. Absolute flux calibration is not required, and the method is insensitive to the strong broadband variability of the host star. Precise calibration of the spectral features of the host star may only be attainable by obtaining deep observations of the system during inferior conjunction that serve as a reference. The high-pass filter spectroscopic technique with the MIRI MRS can be tested on warm Jupiters, Neptunes, and super-Earths with significantly higher planet/star contrast ratios than the Proxima system.

  8. The Brightest Galaxies at Cosmic Dawn: Securing the Largest Samples of z=9-11 galaxies for JWST by leveraging the HST archive with Spitzer/IRAC.

    Science.gov (United States)

    Bouwens, Rychard; Trenti, Michele; Calvi, Valentina; Bernard, Stephanie; Labbe, Ivo; Oesch, Pascal; Coe, Dan; Holwerda, Benne; Bradley, Larry; Mason, Charlotte; Schmidt, Kasper; Illingworth, Garth

    2015-10-01

    Hubble's WFC3 has been a game changer for studying early galaxy formation in the first 700 Myr after the Big Bang. Reliable samples of sources up to z~10, which can be discovered only from space, are now constraining the evolution of the galaxy luminosity function into the epoch of reionization. Despite these efforts, the size of the highest redshift galaxy samples (z >9 and especially z > 10) is still very small, particularly at high luminosities (L > L*). To deliver transformational results, much larger numbers of bright z > 9 galaxies are needed both to map out the bright end of the luminosity/mass function and for spectroscopic follow-up (with JWST and otherwise). One especially efficient way of expanding current samples is (1) to leverage the huge amounts of pure-parallel data available with HST to identify large numbers of candidate z ~ 9 - 11 galaxies and (2) to follow up each candidate with shallow Spitzer/IRAC observations to distinguish the bona- fide z ~ 9 - 11 galaxies from z ~ 2 old, dusty galaxies. For this program we are requesting shallow Spitzer/IRAC follow-up of 20 candidate z ~ 9 - 11 galaxies we have identified from 130 WFC3/IR pointings obtained from more than 4 separate HST programs with no existing IRAC coverage. Based on our previous CANDELS/GOODS searches, we expect to confirm 5 to 10 sources as L > L* galaxies at z >= 9. Our results will be used to constrain the bright end of the LF at z >= 9, to provide targets for Keck spectroscopy to constrain the ionization state of the z > 8 universe, and to furnish JWST with bright targets for spectroscopic follow-up studies.

  9. The Fine-Tuning Argument

    CERN Document Server

    Landsman, Klaas

    2015-01-01

    Our laws of nature and our cosmos appear to be delicately fine-tuned for life to emerge, in way that seems hard to attribute to chance. In view of this, some have taken the opportunity to revive the scholastic Argument from Design, whereas others have felt the need to explain this apparent fine-tuning of the clockwork of the Universe by proposing the existence of a `Multiverse'. We analyze this issue from a sober perspective. Having reviewed the literature and having added several observations of our own, we conclude that cosmic fine-tuning supports neither Design nor a Multiverse, since both of these fail at an explanatory level as well as in a more quantitative context of Bayesian confirmation theory (although there might be other reasons to believe in these ideas, to be found in religion and in inflation and/or string theory, respectively). In fact, fine-tuning and Design even seem to be at odds with each other, whereas the inference from fine-tuning to a Multiverse only works if the latter is underwritten...

  10. 34 CFR 668.84 - Fine proceedings.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Fine proceedings. 668.84 Section 668.84 Education... Proceedings § 668.84 Fine proceedings. (a) Scope and consequences. (1) The Secretary may impose a fine of up... any institution that contracts with the servicer. (2) If the Secretary begins a fine...

  11. The care of fine books

    CERN Document Server

    Greenfield, Jane; Basbanes, Nicholas A

    2014-01-01

    The Care of Fine Books is a thorough, readable guide to caring for books of value. From a discussion of the various techniques and materials used in bookbinding to advice on handling and storage, Jane Greenfield has created a succinct yet complete resource for anyone who wants to preserve and protect their fine books. Whether you are a collector, a librarian, or a conservation professional, you will benefit from this expert advice. Learn about appropriate levels of light, temperature, relative humidity, and pollution; how to secure a collection against fire, insect infestation, flood, and theft; and methods for cleaning and repairing books that have already been damaged. Always practical and amply illustrated, this is a must-have reference for anyone who loves fine books.

  12. Fine bubble generator and method

    Energy Technology Data Exchange (ETDEWEB)

    Bhagat, P.M.; Koros, R.M.

    1990-10-09

    This patent describes a method of forming fine gaseous bubbles in a liquid ambient. It comprises: forcing a gas through orifices located in the liquid ambient while simultaneously forcing a liquid through liquid orifices at a velocity sufficient to form jet streams of liquid, the liquid orifices being equal in number to the gas orifices and so oriented that each jet stream of liquid intersects the gas forced through each gas orifice and creates sufficient turbulence where the gas and jet stream of liquid intersect, whereby fine gaseous bubbles are formed.

  13. Compressive behavior of fine sand.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Bradley E. (Air Force Research Laboratory, Eglin, FL); Kabir, Md. E. (Purdue University, West Lafayette, IN); Song, Bo; Chen, Wayne (Purdue University, West Lafayette, IN)

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  14. Observations of substorm fine structure

    Directory of Open Access Journals (Sweden)

    L. L. Lazutin

    Full Text Available Particle and magnetic field measurements on the CRRES satellite were used, together with geosynchronous satellites and ground-based observations, to investigate the fine structure of a magnetospheric substorm on February 9, 1991. Using the variations in the electron fluxes, the substorm activity was divided into several intensifications lasting about 3–15 minutes each. The two main features of the data were: (1 the intensifications showed internal fine structure in the time scale of about 2 minutes or less. We call these shorter periods activations. Energetic electrons and protons at the closest geosynchronous spacecraft (1990 095 were found to have comparable activation structure. (2 The energetic (>69 keV proton injections were delayed with respect to electron injections, and actually coincided in time with the end of the intensifications and partial returns to locally more stretched field line configuration. We propose that the energetic protons could be able to control the dynamics of the system locally be quenching the ongoing intensification and possibly preparing the final large-scale poleward movement of the activity. It was also shown that these protons originated from the same intensification as the preceeding electrons. Therefore, the substorm instability responsible for the intensifications could introduce a negative feedback loop into the system, creating the observed fine structure with the intensification time scales.

    Key words. Magnetospheric Physics (Storms and substorms.

  15. CDC WONDER: Daily Fine Particulate Matter

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Daily Fine Particulate Matter data available on CDC WONDER are geographically aggregated daily measures of fine particulate matter in the outdoor air, spanning...

  16. CDC WONDER: Daily Fine Particulate Matter

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Daily Fine Particulate Matter data available on CDC WONDER are geographically aggregated daily measures of fine particulate matter in the outdoor air, spanning...

  17. Fine Spectra of Symmetric Toeplitz Operators

    Directory of Open Access Journals (Sweden)

    Muhammed Altun

    2012-01-01

    Full Text Available The fine spectra of 2-banded and 3-banded infinite Toeplitz matrices were examined by several authors. The fine spectra of n-banded triangular Toeplitz matrices and tridiagonal symmetric matrices were computed in the following papers: Altun, “On the fine spectra of triangular toeplitz operators” (2011 and Altun, “Fine spectra of tridiagonal symmetric matrices” (2011. Here, we generalize those results to the (2+1-banded symmetric Toeplitz matrix operators for arbitrary positive integer .

  18. Considering Fine Art and Picture Books

    Science.gov (United States)

    Serafini, Frank

    2015-01-01

    There has been a close association between picturebook illustrations and works of fine art since the picturebook was first conceived, and many ways these associations among works of fine art and picturebook illustrations and design play out. To make sense of all the various ways picturebook illustrations are associated with works of fine art,…

  19. 36 CFR 910.35 - Fine arts.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Fine arts. 910.35 Section 910... DEVELOPMENT AREA Standards Uniformly Applicable to the Development Area § 910.35 Fine arts. Fine arts... of art which are appropriate for the development. For information and guidance, a...

  20. James Webb Space Telescope (JWST) Integrated Science Instruments Module (ISIM) Electronics Compartment (IEC) Conformal Shields Composite Bond Structure Qualification Test Method

    Science.gov (United States)

    Yew, Calinda; Stephens, Matt

    2015-01-01

    The JWST IEC conformal shields are mounted onto a composite frame structure that must undergo qualification testing to satisfy mission assurance requirements. The composite frame segments are bonded together at the joints using epoxy, EA 9394. The development of a test method to verify the integrity of the bonded structure at its operating environment introduces challenges in terms of requirements definition and the attainment of success criteria. Even though protoflight thermal requirements were not achieved, the first attempt in exposing the structure to cryogenic operating conditions in a thermal vacuum environment resulted in approximately 1 bonded joints failure during mechanical pull tests performed at 1.25 times the flight loads. Failure analysis concluded that the failure mode was due to adhesive cracks that formed and propagated along stress concentrated fillets as a result of poor bond squeeze-out control during fabrication. Bond repairs were made and the structures successfully re-tested with an improved LN2 immersion test method to achieve protoflight thermal requirements.

  1. Jet-powered supernovae of $\\sim 10^5\\,M_{\\odot}$ population III stars are observable by $Euclid$, $WFIRST$, $WISH$, and $JWST$

    CERN Document Server

    Matsumoto, Tatsuya; Ioka, Kunihito; Nakamura, Takashi

    2015-01-01

    Supermassive black holes observed at high redshift $z\\gtrsim6$ could grow from direct collapse black holes (DCBHs) with mass $\\sim10^5\\,M_{\\odot}$, which result from the collapse of supermassive stars (SMSs). If a relativistic jet is launched from a DCBH, it can break out of the collapsing SMS and produce a gamma-ray burst (GRB). Although most of the GRB jets are off-axis from our line of sight, we show that the energy injected from the jet into a cocoon is huge $\\sim10^{55-56}\\,{\\rm{erg}}$, so that the cocoon fireball is observed as ultra-luminous supernovae of $\\sim10^{45-46}\\rm{\\,erg\\,s^{-1}}$ for $\\sim5000 [(1+z)/16] \\rm{\\,days}$. They are detectable by the future telescopes with near infrared bands, such as, $Euclid$, $WFIRST$, $WISH$, and $JWST$ up to $z\\sim20$ and $\\sim 100$ events per year, providing a direct evidence of the DCBH scenario.

  2. Optical phase curves of exoplanets at small and large phase angles

    Science.gov (United States)

    García Muñoz, Antonio

    2016-10-01

    Phase curves and secondary eclipses provide key information on exoplanet atmospheres. Indeed, recent work on close-in giant planets observed by Kepler has shown that it is possible to constrain various reflecting, dynamical and thermal properties of their atmospheres from the analysis of the planets' phase curves. This presentation discusses new diagnostic possibilities for the characterization of exoplanet atmospheres with optical phase curves. These possibilities benefit from the fact that at optical wavelengths the signal from the planet is either partly or mostly determined by scattering of starlight within its atmosphere, which entails that the structure of the planet's phase curve mimics to some extent the optical properties of the atmospheric medium. In particular, we will show how cloud properties such as the particle size or the atmospheric scale height might be constrained through observations at small (i.e. near transit) and large (i.e. near occultation) phase angles. We will emphasize how the interpretation of optical phase curves differs from the interpretation of phase curves obtained at longer wavelengths. The conclusions are relevant to the study of Kepler planets, but also to the investigation of phase curves to be delivered by upcoming space missions such as CHEOPS, JWST, PLATO and TESS.

  3. The origin of the distortion product otoacoustic emission fine structure

    Science.gov (United States)

    Piskorski, Pawel

    Distortion-product otoacoustic emissions (DPOAEs) are sounds detected in the ear canal which are generated by the nonlinear processes in the inner ear (cochlea) in response to the external stimulation of two or more tones (primaries). Their generation region in the cochlea can be systematically changed by varying the primary frequencies, and they are currently being evaluated for possible clinical use in screening for hearing defects. The phase and amplitude of various orders of DPOAEs of frequencies, f/sb [dp]=f1-n(f2-f1),/ (n=1,2,/...), were measured in human subjects for two- tone stimuli of frequencies f1 and f2 (>f1). A number of experimental paradigms (fixed primary ratio f2/f1, fixed f1, fixed f2, and fixed f/sb [dp]) were used to investigate the nature of peaks and valleys (fine structure) of DPOAEs in their phase and amplitude dependence on the primary frequencies. This fine structure must be taken into account in any potential clinical applications of DPOAEs. The experimental results largely support a model in which the fine structure stems from interference at the base of the cochlea between distortion product (DP) components coming from the primary DPOAE source region (around the f2 tonotopic place) and components coming from the DP tonotopic place (via reflection of an apically moving DP wave). The spectral periodicity of the fine structures for several orders of apical DPOAEs corresponds to a tonotopic displacement of about 0.4 mm along the basilar membrane (BM) (0.4 bark). In agreement with the reaction model, this spectral spacing is also characteristic of synchronous evoked and spontaneous otoacoustic emission spectra as well as the microstructure of the hearing threshold. Approximate analytic expressions for the mechanisms which are responsible for the fine structure are used to interpret the data.

  4. Southern Fine Particulate Monitoring Project

    Energy Technology Data Exchange (ETDEWEB)

    Ashley Williamson

    2003-05-31

    This final project report presents experimental details, results and analysis of continuous onsite ambient fine particulate data at the North Birmingham sampling site during the October, 2001-September, 2002 study period.The host site for these measurement activities is the North Birmingham PM monitoring station by the Jefferson County Health Department in Birmingham, AL.The continuous data include PM{sub 2.5} mass concentrations measured by TEOM, particle sulfate using the R&P 8400S monitor, particle size distributions measured by SMPS and APS monitors, and PM{sub 2.5} light scattering extinction coefficient as measured by nephelometer. During the course of the project, measurement intercomparison data were developed for these instruments and several complementary measurements at the site. The report details the instrument set and operating procedures and describes the resulting data. Report subsections present an overview summary of the data, followed by detailed description of the systematic time behavior of PM{sub 2.5} and other specific particulate size fractions. Specific subsections are included for particle size distribution, light scattering, and particle sulfate data. The final subsection addresses application of the measurements to the practical questions of fine PM generation and transport, source attribution, and PM{sub 2.5} management strategies.

  5. Interactions of fines with base fractions of oil and its implication in smart water flooding

    DEFF Research Database (Denmark)

    Chakravarty, Krishna Hara; Fosbøl, Philip Loldrup; Thomsen, Kaj

    2015-01-01

    Migration of fines, and formation of oil emulsion have been independently observed during smart water flooding both have been suggested to play a vital role in enhanced oil recovery (EOR). But, the exact role of fines and the reason of emulsion formation are not well studied for carbonate reservo...... reservoirs. This study shows that addition of water and crude oil on calcite fines leads to formation of soluble oil emulsions in the water phase. Formation of these emulsions and its implication in EOR has been experimentally analyzed.......Migration of fines, and formation of oil emulsion have been independently observed during smart water flooding both have been suggested to play a vital role in enhanced oil recovery (EOR). But, the exact role of fines and the reason of emulsion formation are not well studied for carbonate...

  6. Fine-tuning challenges for the matter bounce scenario

    CERN Document Server

    Levy, Aaron M

    2016-01-01

    A bouncing universe with a long period of contraction during which the average density is pressureless (the same equation of state as matter) as cosmologically observable scales exit the Hubble horizon has been proposed as an explanation for producing a nearly scale-invariant spectrum of adiabatic scalar perturbations. A well-known problem with this scenario is that, unless suppressed, the energy density associated with anisotropy grows faster than that of the pressureless matter, so the matter-like phase is unstable. Previous models introduce an ekpyrotic phase after the matter-like phase to prevent the anisotropy from generating chaotic mixmaster behavior. In this work, though, we point out that, unless the anisotropy is suppressed first, the matter-like phase will never start and that suppressing the anisotropy requires extraordinary, exponential fine-tuning.

  7. Interactions of fines with base fractions of oil and its implication in smart water flooding

    DEFF Research Database (Denmark)

    Chakravarty, Krishna Hara; Fosbøl, Philip Loldrup; Thomsen, Kaj

    2015-01-01

    Migration of fines, and formation of oil emulsion have been independently observed during smart water flooding both have been suggested to play a vital role in enhanced oil recovery (EOR). But, the exact role of fines and the reason of emulsion formation are not well studied for carbonate...... reservoirs. This study shows that addition of water and crude oil on calcite fines leads to formation of soluble oil emulsions in the water phase. Formation of these emulsions and its implication in EOR has been experimentally analyzed....

  8. Characterization of fine organic particulate matter from Chinese cooking

    Institute of Scientific and Technical Information of China (English)

    HE Ling-yan; HU Min; WANG Li; HUANG Xiao-feng; ZHANG Yuan-hang

    2004-01-01

    PM2.5 samples were collected by a three-stage cascade impactor at two kinds of Chinese restaurants to characterize fine organic particulate matter from Chinese cooking sources. Major individual organic compounds have been quantified by GC/MS, including series of alkanes, n-alkanoic acids, n-alkanals, alkan-2-ones and PAHs.Alkanes and ketones make up a significant fraction of particle-phase organic compounds, ranging from C11 to C26,and C9 to C19, respectively. In addition, other organic compound classes have been identified, such as alkanols,esters, furans, lactones, amides, and nitriles. The mass concentrations of fine particles, alkanes, n-alkanoic acids and PAHs in air emitted from the Uigur style cooking are hundreds times higher than ambient PM2.5 in Beijing.

  9. Characterization of Ultra Fine Solids(BS) in Athabasca Bitumen

    Institute of Scientific and Technical Information of China (English)

    LI Zai-Feng(李再峰); Judy KUNG; TU Yun(涂云); Luba S.KOTLYAR; Keng H.CHUNG

    2004-01-01

    The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm.The result of PAS FTIR and image of TEM showed that the structure of BS particles was smiliar to that of kaolinite clay.On the surface of BS,both toluene insoluble organic matter and structural OH group are detected at the same time.The surface characteristics imparted a bi-wettable nature to the BS.As a result,the BS is able to stabilize fine water emulsion in the bitumen phase.The organic matter associated with BS is a possible factor of the fouling on catalyst and equipment.

  10. Advanced Fine Particulate Characterization Methods

    Energy Technology Data Exchange (ETDEWEB)

    Steven Benson; Lingbu Kong; Alexander Azenkeng; Jason Laumb; Robert Jensen; Edwin Olson; Jill MacKenzie; A.M. Rokanuzzaman

    2007-01-31

    The characterization and control of emissions from combustion sources are of significant importance in improving local and regional air quality. Such emissions include fine particulate matter, organic carbon compounds, and NO{sub x} and SO{sub 2} gases, along with mercury and other toxic metals. This project involved four activities including Further Development of Analytical Techniques for PM{sub 10} and PM{sub 2.5} Characterization and Source Apportionment and Management, Organic Carbonaceous Particulate and Metal Speciation for Source Apportionment Studies, Quantum Modeling, and High-Potassium Carbon Production with Biomass-Coal Blending. The key accomplishments included the development of improved automated methods to characterize the inorganic and organic components particulate matter. The methods involved the use of scanning electron microscopy and x-ray microanalysis for the inorganic fraction and a combination of extractive methods combined with near-edge x-ray absorption fine structure to characterize the organic fraction. These methods have direction application for source apportionment studies of PM because they provide detailed inorganic analysis along with total organic and elemental carbon (OC/EC) quantification. Quantum modeling using density functional theory (DFT) calculations was used to further elucidate a recently developed mechanistic model for mercury speciation in coal combustion systems and interactions on activated carbon. Reaction energies, enthalpies, free energies and binding energies of Hg species to the prototype molecules were derived from the data obtained in these calculations. Bimolecular rate constants for the various elementary steps in the mechanism have been estimated using the hard-sphere collision theory approximation, and the results seem to indicate that extremely fast kinetics could be involved in these surface reactions. Activated carbon was produced from a blend of lignite coal from the Center Mine in North Dakota and

  11. SOUTHERN FINE PARTICULATE MONITORING PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-04-01

    This quarterly report presents results and analysis of continuous onsite ambient fine particulate data at the North Birmingham sampling site during the January-March, 2002 study period. The continuous data include PM{sub 2.5} mass concentrations measured by TEOM, particle sulfate using the R&P 8400S monitor, particle size distributions measured by SMPS and APS monitors, and PM{sub 2.5} light scattering extinction coefficient as measured by nephelometer. Some instrumental issues were noted with the upgrade of the APS model 3320 are described in the report, as well as preliminary performance indications for the upgraded instrument. During the quarter preliminary data analysis and modeling studies were conducted to test the potential of the North Birmingham site data for source attribution analyses. Our initial assessment has continued to be optimistic in this regard due to the location of the site relative to several important classes of local and midrange emission sources. We anticipate that these analyses will provide good separations of the effects of major source classes and spatial source clusters, and will provide useful information relevant to PM{sub 2.5} implementation strategies.

  12. Fine needle aspiration cytology of rectal masses.

    Science.gov (United States)

    Kochhar, R; Rajwanshi, A; Wig, J D; Gupta, N M; Kesiezie, V; Bhasin, D K; Malik, A K; Gupta, S K; Mehta, S K

    1990-01-01

    This paper describes the results of transproctoscopic fine needle aspiration cytology in the diagnosis of rectal lesions. Fifty one consecutive patients referred with a presumptive diagnosis of rectal mass were subjected to proctoscopic examination when fine needle aspiration cytology, brush cytology and biopsy samples were taken. Of the 30 patients of malignancy of rectum in whom all the three sampling techniques were applied, the biopsy was positive in 27 (90%), brush cytology in 25 (83.3%) and fine needle aspiration cytology in 29 (96.6%). A combination of fine needle aspiration cytology with brush cytology gave a positive yield in 96.6% while that fine needle aspiration cytology with brush cytology gave a yield of 100%. Fine needle aspiration cytology was most helpful in infiltrative tumours. All 10 patients with secondaries in the pouch of Douglas or rectovesical pouch, and the single patient with submucosal rectal carcinoma were correctly diagnosed at fine needle aspiration cytology. There were no false positive results with fine needle aspiration cytology and no complications were encountered with the procedure. Images Figure 1 Figure 2 Figure 3 PMID:2323600

  13. 47 CFR 76.943 - Fines.

    Science.gov (United States)

    2010-10-01

    ... TELEVISION SERVICE Cable Rate Regulation § 76.943 Fines. (a) A franchising authority may impose fines or... specifically at the cable operator, provided the franchising authority has such power under state or local laws. (b) If a cable operator willfully fails to comply with the terms of any franchising authority's...

  14. Magnetofluidization of fine magnetite powder.

    Science.gov (United States)

    Valverde, J M; Espin, M J; Quintanilla, M A S; Castellanos, A

    2009-03-01

    The behavior of a fluidized bed of fine magnetite particles as affected by a cross-flow magnetic field is investigated. A distinct feature of this naturally cohesive powder, as compared to noncohesive magnetic grains usually employed in magnetofluidized beds, is that the fluidized bed displays a range of stable fluidization even in the absence of an external magnetic field. Upon application of the magnetic field, the interval of stable fluidization is extended to higher gas velocities and bed expansion is enhanced. We have measured the tensile strength as affected by application of the external magnetic field according to two different operation modes. In the H off-on operation mode, the bed is driven to bubbling in the absence of external magnetic field. Once the gas velocity is decreased below the bubbling onset and the bed has returned to stable fluidization due to natural cohesive forces, the field is applied. In the H on-on mode, the field is maintained during the whole process of bubbling and return to stable fluidization. It is found that the tensile strength of the naturally stabilized bed is not essentially changed by application of the field ( H off-on) since the magnetic field cannot alter the bed structure once the particles are jammed in the stable fluidization state. Magnetic forces within the bulk of the jammed bed are partially canceled as a result of the anisotropic nature of the dipole-dipole interaction between the particles, which gives rise to just a small increment of the tensile strength. On the other hand, when the field is held on during bubbling and transition to stable fluidization ( H on-on mode), the tensile strength is appreciably increased. This suggests the formation of particle chains when the particles are not constrained due to the dipole-dipole attractive interaction which affects the mechanical strength of the stably fluidized bed. Experimental data are analyzed in the light of theoretical models on magnetic surface stresses.

  15. INTERACTIONS BETWEEN CATIONIC POLYELECTROLYTE AND PULP FINES

    Directory of Open Access Journals (Sweden)

    Elina Orblin

    2011-05-01

    Full Text Available Papermaking pulps are a mixture of fibres, fibre fragments, and small cells (parenchyma or ray cells, usually called pulp fines. The interactions between pulp fines and a cationic copolymer of acrylamide and acryloxyethyltrimethyl ammonium chloride were investigated based on solid-liquid isotherms prepared under different turbulence, and subsequent advanced surface characterization using X-ray photoelectron spectroscopy (XPS and time-of-flight secondary ion mass spectrometry (ToF-SIMS. The surface charge and surface area of pulp fine substrates were measured by methylene blue sorption-XPS analysis and nitrogen adsorption combined with mercury porosimetry, respectively. The driving force behind polyelectrolyte adsorption was the amount of the surface anionic charge, whereas surface area appeared to be of less importance. Based on a comparison of solid-liquid and XPS sorption isotherms, different polyelectrolyte conformations were suggested, depending on the types of fines: A flatter conformation and partial cell-wall penetration of polyelectrolytes on kraft fines from freshly prepared pulp, and a more free conformation with extended loops and tails on lignocellulosic fines from recycled pulp. Additionally, ToF-SIMS imaging proved that recycled pulp fines contained residual de-inking chemicals (primarily palmitic acid salts that possibly hinder the electrostatic interactions with polyelectrolytes.

  16. Dark Energy with a Fine-toothed Comb

    CERN Document Server

    Linder, E V

    2006-01-01

    The cosmological constant and many other possible origins for acceleration of the cosmic expansion possess variations in the dark energy properties slow on the Hubble time scale. Given that models with more rapid variation, or even phase transitions, are possible though, we examine the fineness in redshift with which cosmological probes can realistically be employed, and what constraints this could impose on dark energy behavior. In particular, we discuss various aspects of baryon acoustic oscillations, and their use to measure the Hubble parameter H(z). We find that cosmological probes have an innate resolution no finer than Delta z=0.2-0.3.

  17. Fine-Filament MgB2 Superconductor Wire

    Science.gov (United States)

    Cantu, Sherrie

    2015-01-01

    Hyper Tech Research, Inc., has developed fine-filament magnesium diboride (MgB2) superconductor wire for motors and generators used in turboelectric aircraft propulsion systems. In Phase I of the project, Hyper Tech demonstrated that MgB2 multifilament wires (MgB2 rotor coil packs for a superconducting generator. The ultimate goal is to enable low-cost, round, lightweight, low-AC-loss superconductors for motor and generator stator coils operating at 25 K in next-generation turboelectric aircraft propulsion systems.

  18. Microwave-assisted hydrothermal synthesis of lead zirconate fine powders

    Directory of Open Access Journals (Sweden)

    Apinpus Rujiwatra

    2011-01-01

    Full Text Available A rapid synthesis of lead zirconate fine powders by microwave-assisted hydrothermal technique is reported. The influences of type of lead precursor, concentration of potassium hydroxide mineraliser, applied microwave power and irradiation time are described. The synthesised powders were characterised by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopic microanalysis and light scattering technique. The merits of the microwave application in reducing reaction time and improving particle mono-dispersion and size uniformity as well as the drawbacks, viz. low purity of the desired phase and increasing demand of mineraliser, are discussed in relation to conventional heating method.

  19. Abrasion of ultrafine WC-Co by fine abrasive particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Abrasive wear of a series of WC-(5%-14%, mass fiaction)Co hardmetals was investigated employing coarse and fine SiC abrasive under two-body dry abrasion conditions with pin-on-disc and edge-on-disc test arrangements. Unexpectedly, it is found that submicron grades demonstrate substantially higher wear rates comparing with the coarse grades if fine abrasive is utilized in pin-on-disc tests. Such a behavior is attributed to changes in a ratio of abrasive size to size of hard phase as finer abrasive is used.The edge-on-disc test demonstrates that edge wear may be described in two stages with the highest wear rates at the beginning stage.This behavior is associated with a transition of wear mechanisms as edge is wider due to wear. Compared with the ultrafine grades of the same Co content, the coarse grades demonstrate higher wear rates at the beginning, but lower wear rates at the final stage. Wear rates and mechanisms observed at final stage correlate well to the results observed for pin-on-disc tests employing fine abrasive.

  20. Flow and Transport of Fines in Dams and Embankments

    Science.gov (United States)

    Glascoe, L. G.; Ezzedine, S. M.; Kanarska, Y.; Lomov, I.; Antoun, T.; Woodson, S. C.; Hall, R. L.; Smith, J.

    2013-12-01

    Understanding the flow of fines in porous media and fractured media is significant for industrial, environmental, geotechnical and petroleum technologies to name a few. Several models have been proposed to simulate the flow and transport of fines using single or two-phase flow approaches while other models rely on mobile and immobile transport approaches. However, to the authors' best knowledge, all the proposed modeling approaches have not been compared to each other in order to define their limitations and domain of validation. In the present study, several models describing the transport of fines in heterogeneous porous and fractured media will be presented and compared to each other. Furthermore, we will evaluate their performance on the same published experimental sets of published data. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was sponsored by the Department of Homeland Security (DHS), Science and Technology Directorate, Homeland Security Advanced Research Projects Agency (HSARPA).

  1. Fine Art Fair Held in September

    Institute of Scientific and Technical Information of China (English)

    Guo Yan

    2011-01-01

    "Ihe Art Beijing 2011· Fine Art Fair was held at the National Agricultural Exhibition Center in Beijing from September 15 to 18, 2011. Bringing together over 40 galleries and art institutions, this year's Fine Art Beijing offers a strong lineup. It presented an extraordinary exhibition of both classical and modem art from West and East. Compared with previous fairs, the exhibits at the Fine Art Beijing 2011 are richer in form and more diversified in style. Attending the fair,

  2. Phase transformation and diffusion

    CERN Document Server

    Kale, G B; Dey, G K

    2008-01-01

    Given that the basic purpose of all research in materials science and technology is to tailor the properties of materials to suit specific applications, phase transformations are the natural key to the fine-tuning of the structural, mechanical and corrosion properties. A basic understanding of the kinetics and mechanisms of phase transformation is therefore of vital importance. Apart from a few cases involving crystallographic martensitic transformations, all phase transformations are mediated by diffusion. Thus, proper control and understanding of the process of diffusion during nucleation, g

  3. Effect of Fine Steel Slag Powder on the Early Hydration Process of Portland Cement

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Hydration heat evolution, non-evaporative water, setting time and SEM tests were performed to investigate the effect of fine steel slag powder on the hydration process of Portland cement and its mechanism.The results show that the effect of fine steel slag powder on the hydration process of Portland cement is closely related to its chemical composition, mineral phases, fineness, etc.Fine steel slag powder retards the hydration of portland cement at early age.The major reason for this phenomenon is the relative high content of MgO , MnO2, P2 O5in steel slag, and MgO solid solved in C3 S contained in steel slag.

  4. About Phase: Synthetic Aperture Radar and the Phase Retrieval

    Science.gov (United States)

    2014-03-01

    apply certain ideas from phase retrieval to resolve phase errors in SAR . Specifically, we use bistatic techniques to measure relative phases, and then we...imaging a scene of interest (left) using bistatic SAR techniques at three different times. As in Example 5.5, at the first time instant the aircraft are...Synthetic aperture radar ( SAR ) uses relative motion to produce fine resolution images from microwave frequencies and is a useful tool for regular

  5. Ultra fine tantalum powder for advanced capacitors

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Ultra fine tantalum and niobium powders are applicable in many areas of engineering. Of particular significance are high purity powders that are usable in production of high capacitance capacitors and superconductors.

  6. Ultra fine tantalum powder for advanced capacitors

    Institute of Scientific and Technical Information of China (English)

    Nebera; A.; Markusbkin; Yu.; Azarov; V.; Ermolaev; N.

    2005-01-01

    Ultra fine tantalum and niobium powders are applicable in many areas of engineering. Of particular significance are high purity powders that are usable in production of high capacitance capacitors and superconductors.……

  7. DESIGN INFORMATION ON FINE PORE AERATION SYSTEMS

    Science.gov (United States)

    Field studies were conducted over several years at municipal wastewater treatment plants employing line pore diffused aeration systems. These studies were designed to produce reliable information on the performance and operational requirements of fine pore devices under process ...

  8. NEW RSW & Wall Fine Fully Tetrahedral Grid

    Data.gov (United States)

    National Aeronautics and Space Administration — NEW RSW Fine Fully Tetrahedral Grid with Viscous Wind Tunnel wall at the root. This grid is for a node-based unstructured solver. Note that the CGNS file is very...

  9. NEW RSW & Wall Fine Mixed Element Grid

    Data.gov (United States)

    National Aeronautics and Space Administration — RSW Fine Mixed Element Grid with viscous root wind tunnel wall. This grid is for a node-based unstructured solver. Quad Surface Faces= 38016 Tria Surface Faces=...

  10. Immobilization of Rocky Flats Graphite Fines Residue

    Energy Technology Data Exchange (ETDEWEB)

    Rudisill, T.S.

    1999-04-06

    The development of the immobilization process for graphite fines has proceeded through a series of experimental programs. The experimental procedures and results from each series of experiments are discussed in this report.

  11. Fine 5 Eesti tantsuväljal / Iiris Viirpalu

    Index Scriptorium Estoniae

    Viirpalu, Iiris, 1992-

    2017-01-01

    Nüüdistantsuteatril Fine 5 täitub tänavu 25. tegutsemisaasta. Fine 5 käekirjast. Vestlusest Fine 5 tantsuteatri ja -kooli kauaaegsete kunstiliste juhtide Renee Nõmmiku ja Tiina Olleskiga Eesti tantsukunstist

  12. Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid

    Science.gov (United States)

    ... Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid An ultrasound-guided thyroid biopsy uses sound waves ... Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid? During a fine needle aspiration biopsy of the ...

  13. Revisiting fine-tuning in the MSSM

    Science.gov (United States)

    Ross, Graham G.; Schmidt-Hoberg, Kai; Staub, Florian

    2017-03-01

    We evaluate the amount of fine-tuning in constrained versions of the minimal supersymmetric standard model (MSSM), with different boundary conditions at the GUT scale. Specifically we study the fully constrained version as well as the cases of non-universal Higgs and gaugino masses. We allow for the presence of additional non-holomorphic soft-terms which we show further relax the fine-tuning. Of particular importance is the possibility of a Higgsino mass term and we discuss possible origins for such a term in UV complete models. We point out that loop corrections typically lead to a reduction in the fine-tuning by a factor of about two compared to the estimate at tree-level, which has been overlooked in many recent works. Taking these loop corrections into account, we discuss the impact of current limits from SUSY searches and dark matter on the fine-tuning. Contrary to common lore, we find that the MSSM fine-tuning can be as small as 10 while remaining consistent with all experimental constraints. If, in addition, the dark matter abundance is fully explained by the neutralino LSP, the fine-tuning can still be as low as ˜ 20 in the presence of additional non-holomorphic soft-terms. We also discuss future prospects of these models and find that the MSSM will remain natural even in the case of a non-discovery in the foreseeable future.

  14. Pelletization of fine coals. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, K.V.S.

    1995-12-31

    Coal is one of the most abundant energy resources in the US with nearly 800 million tons of it being mined annually. Process and environmental demands for low-ash, low-sulfur coals and economic constraints for high productivity are leading the coal industry to use such modern mining methods as longwall mining and such newer coal processing techniques as froth flotation, oil agglomeration, chemical cleaning and synthetic fuel production. All these processes are faced with one common problem area--fine coals. Dealing effectively with these fine coals during handling, storage, transportation, and/or processing continues to be a challenge facing the industry. Agglomeration by the unit operation of pelletization consists of tumbling moist fines in drums or discs. Past experimental work and limited commercial practice have shown that pelletization can alleviate the problems associated with fine coals. However, it was recognized that there exists a serious need for delineating the fundamental principles of fine coal pelletization. Accordingly, a research program has been carried involving four specific topics: (i) experimental investigation of coal pelletization kinetics, (ii) understanding the surface principles of coal pelletization, (iii) modeling of coal pelletization processes, and (iv) simulation of fine coal pelletization circuits. This report summarizes the major findings and provides relevant details of the research effort.

  15. Accelerated Adaptive MGS Phase Retrieval

    Science.gov (United States)

    Lam, Raymond K.; Ohara, Catherine M.; Green, Joseph J.; Bikkannavar, Siddarayappa A.; Basinger, Scott A.; Redding, David C.; Shi, Fang

    2011-01-01

    The Modified Gerchberg-Saxton (MGS) algorithm is an image-based wavefront-sensing method that can turn any science instrument focal plane into a wavefront sensor. MGS characterizes optical systems by estimating the wavefront errors in the exit pupil using only intensity images of a star or other point source of light. This innovative implementation of MGS significantly accelerates the MGS phase retrieval algorithm by using stream-processing hardware on conventional graphics cards. Stream processing is a relatively new, yet powerful, paradigm to allow parallel processing of certain applications that apply single instructions to multiple data (SIMD). These stream processors are designed specifically to support large-scale parallel computing on a single graphics chip. Computationally intensive algorithms, such as the Fast Fourier Transform (FFT), are particularly well suited for this computing environment. This high-speed version of MGS exploits commercially available hardware to accomplish the same objective in a fraction of the original time. The exploit involves performing matrix calculations in nVidia graphic cards. The graphical processor unit (GPU) is hardware that is specialized for computationally intensive, highly parallel computation. From the software perspective, a parallel programming model is used, called CUDA, to transparently scale multicore parallelism in hardware. This technology gives computationally intensive applications access to the processing power of the nVidia GPUs through a C/C++ programming interface. The AAMGS (Accelerated Adaptive MGS) software takes advantage of these advanced technologies, to accelerate the optical phase error characterization. With a single PC that contains four nVidia GTX-280 graphic cards, the new implementation can process four images simultaneously to produce a JWST (James Webb Space Telescope) wavefront measurement 60 times faster than the previous code.

  16. Modeling of Fine-Particle Formation in Turbulent Flames

    Science.gov (United States)

    Raman, Venkat; Fox, Rodney O.

    2016-01-01

    The generation of nanostructured particles in high-temperature flames is important both for the control of emissions from combustion devices and for the synthesis of high-value chemicals for a variety of applications. The physiochemical processes that lead to the production of fine particles in turbulent flames are highly sensitive to the flow physics and, in particular, the history of thermochemical compositions and turbulent features they encounter. Consequently, it is possible to change the characteristic size, structure, composition, and yield of the fine particles by altering the flow configuration. This review describes the complex multiscale interactions among turbulent fluid flow, gas-phase chemical reactions, and solid-phase particle evolution. The focus is on modeling the generation of soot particles, an unwanted pollutant from automobile and aircraft engines, as well as metal oxides, a class of high-value chemicals sought for specialized applications, including emissions control. Issues arising due to the numerical methods used to approximate the particle number density function, the modeling of turbulence-chemistry interactions, and model validation are also discussed.

  17. Transition metals in coarse, fine, very fine and ultra-fine particles from an interstate highway transect near Detroit

    Science.gov (United States)

    Cahill, Thomas A.; Barnes, David E.; Lawton, Jonathan A.; Miller, Roger; Spada, Nicholas; Willis, Robert D.; Kimbrough, Sue

    2016-11-01

    As one component of a study investigating the impact of vehicle emissions on near-road air quality, human exposures, and potential health effects, particles were measured from September 21 to October 30, 2010 on both sides of a major roadway (Interstate-96) in Detroit. Traffic moved freely on this 12 lane freeway with a mean velocity of 69 mi/hr. with little braking and acceleration. The UC Davis DELTA Group rotating drum (DRUM) impactors were used to collect particles in 8 size ranges at sites nominally 100 m south, 10 m north, 100 m north, and 300 m north of the highway. Ultra-fine particles were continuously collected at the 10 m north and 100 m north sites. Samples were analyzed every 3 h for mass (soft beta ray transmission), 42 elements (synchrotron-induced x-ray fluorescence) and optical attenuation (350-800 nm spectroscopy). A three day period of steady southerly winds along the array allowed direct measurement of freeway emission rates for coarse (10 > Dp > 1.0 μm), PM2.5, very fine (0.26 > Dp > 0.09 μm), and ultra-fine (Dp car and truck emission rates of 1973, this value would have been about 16 μg/m3, corrected down from the 19 μg/m3 PM5.0 using measured roadway dust contributions. This would have included 2.7 μg/m3 of lead, versus the 0.0033 μg/m3 measured. Very fine particles were distributed across the array with a relatively weak falloff versus distance. For the ultra-fine particles, emissions of soot and metals seen in vehicular braking studies correlated with traffic at the 10 m site, but only the soot was statistically significant at the 100 m north site. Otherwise, the 10 m north and 100 m north sites were essentially identical in mean concentration and highly correlated in time for most of the 5 week study. This result supports earlier publications showing the ability of very fine and ultra-fine particles to transport to sites well removed from the freeway sources. The concentrations of very fine and ultra-fine metals from brake wear and

  18. Fine water spray system: Extinguishing tests in medium and full-scale turbine hood

    Science.gov (United States)

    Wighus, R.; Aune, P.; Drangsholt, G.; Stensaas, J. P.

    1994-12-01

    The report is based on the results from two test series, called Phase 1 and Phase 2 of the project 'Halon Replacement by Fine Water Spray Technology - Turbine Hood application'. Detailed results are presented in technical reports from Phase 1 and Phase 2. The tests were carried out in two different scales, one 30 cu m test enclosure formerly used to characterize different water spray nozzles, and a full scale 70 cu m model of a turbine hood. The scope of work in Phase 1 was to identify the extinguishing characteristics of various nozzles developed by BP Sunbury Research Center, UK, and to verify the efficiency of a total fire suppression system developed by Ginge-Kerr Offshore. The fire suppression system uses a twin-fluid nozzles using air and water at pressures about 5 bar. The nozzles produce a water spray with small droplets and high velocity. The scope of work of Phase 2 was to verify the efficiency of the Fine Water Spray nozzles fighting a variety of fire scenarios which may occur in a real turbine hood. A full scale test enclosure containing a mock-up of a turbine heated internally to simulate hot metal surfaces, with insulation mats and piping as in a real turbine hood was constructed in the large test hall of SINTEF NBL. The turbine hood model was built by elements of a Multipurpose Fire Test Rig. Realistic fires with Diesel pool- and spray fires, fires in insulation mats soaked with Diesel oil under different ventilation conditions were ignited in the turbine hood model. Number of Fine Water Spray nozzles, nozzle position and spraying sequences were varied. A base for design of a Fine Water Spray system for a turbine hood is developed, and several unique features of the performance of a Fine Water Spray fire suppression system have been documented.

  19. The effect of the presence of fine YSZ particles on the performance of porous nickel electrodes

    NARCIS (Netherlands)

    Boer, de B.; Gonzalez, M.; Bouwmeester, H.J.M.; Verweij, H.

    2000-01-01

    The electrochemical performance of a porous nickel electrode with its surface modified by deposition with fine yttria-stabilised zirconia (YSZ) powder is compared with that of the ‘bare’ electrode. Image analysis of the electrode microstructure yields values for the triple phase boundary (TPB) lengt

  20. GeneRecon—A coalescent based tool for fine-scale association mapping

    DEFF Research Database (Denmark)

    Mailund, Thomas; Schierup, Mikkel Heide; Pedersen, Christian Nørgaard Storm

    2006-01-01

    GeneRecon is a tool for fine-scale association mapping using a coalescence model. GeneRecon takes as input case-control data from phased or unphased SNP and micro-satellite genotypes. The posterior distribution of disease locus position is obtained by Metropolis Hastings sampling in the state space...

  1. Liposomal amphotericin B dry powder inhaler: effect of fines on in vitro performance.

    Science.gov (United States)

    Shah, S P; Misra, A

    2004-10-01

    The aim of the present investigation was to improve in vitro pulmonary deposition of amphotericin B (AMB) liposomal dry powder inhaler (LDPI) formulations. Liposomes with negative (AMB1) and positive (AMB2) charge were prepared by the reverse phase evaporation (REV) technique, extruded to reduce size, separated from unentrapped drug and lyophilized using an optimized cryoprotectant to achieve maximum drug retention. Lactose carrier (Sorbolac 400) in varying mass ratio with or without addition of fines (500# sieved Pharmatose 325M) in different mixing sequence were used to formulate AMB LDPI formulations. In vitro evaluation was done with twin stage impinger (TSI) for fine particle fraction. The lactose carrier containing 10% fines was found to be optimum blend at 1:6 mass ratio of liposome: lactose. The addition of fines and order of mixing fines were found to influence the fine particle fraction (FPF) significantly. FPF of LDPI formulations using a Rotahaler (Cipla, India) as delivery device at 30, 60 and 90 L/min were found to be 23.1 +/- 1.5 percent and 17.3 +/- 2.2 percent; 25.3 +/- 1.8 percent and 19.6 +/- 1.5 percent and 28.4 +/- 2.1 percent and 22.9 +/- 1.9 percent for AMB1 and AMB2 respectively.

  2. Charge neutrality of fine particle (dusty) plasmas and fine particle cloud under gravity

    Science.gov (United States)

    Totsuji, Hiroo

    2017-03-01

    The enhancement of the charge neutrality due to the existence of fine particles is shown to occur generally under microgravity and in one-dimensional structures under gravity. As an application of the latter, the size and position of fine particle clouds relative to surrounding plasmas are determined under gravity.

  3. INFLUENCE OF ADSORBED AND DISSOLVED CARBOXYMETHYL CELLULOSE ON FIBRE SUSPENSION DISPERSING, DEWATERABILITY, AND FINES RETENTION

    Directory of Open Access Journals (Sweden)

    Henrikki Liimatainen

    2009-02-01

    Full Text Available The effect of adsorbed and soluble carboxymethyl cellulose (CMC on dispersing, dewaterability, and fines retention of pulp fibre suspensions was investigated. CMC was added to a suspension in the presence of electrolytes, causing its adsorption to the fibre surfaces, or to a suspension without electrolytes, so that it stayed in the liquid phase. Both the CMC adsorbed on fibre surfaces and that in the liquid phase were able to disperse the fibre suspension due to the ability of CMC to reduce fibre-to-fibre friction in both phases. Adsorbed CMC promoted the formation of a water-rich microfibrillar gel on the fibre surfaces through the spreading out of microfibrils, leading to a decrease in friction at the fibre-fibre contact points and to the increased dispersion of fibres. CMC in the liquid phase of the suspension was in turn thought to prevent fibre-to-fibre contacts due to the large physical size of the CMC molecules. CMC in both phases had detrimental effects on dewatering of the pulp suspension, but adsorbed CMC caused more plugging of the filter cake, and this was attributed to its ability to disperse fibre fines, in particular. Thus, adsorbed CMC also reduced fines retention considerably more than did CMC in the liquid phase of a suspension.

  4. 76 FR 31307 - Commission of Fine Arts; Notice of Meeting

    Science.gov (United States)

    2011-05-31

    ... From the Federal Register Online via the Government Publishing Office COMMISSION OF FINE ARTS Commission of Fine Arts; Notice of Meeting The next meeting of the U.S. Commission of Fine Arts is scheduled... oral statements should be addressed to Thomas Luebke, Secretary, U.S. Commission of Fine Arts, at...

  5. Towards gloss control in fine art reproduction

    Science.gov (United States)

    Baar, Teun; Brettel, Hans; Ortiz Segovia, Maria V.

    2015-03-01

    The studies regarding fine art reproduction mainly focus on the accuracy of colour and the recreation of surface texture properties. Since reflection properties other than colour are neglected, important details of the artwork are lost. For instance, gloss properties, often characteristic to painters and particular movements in the history of art, are not well reproduced. The inadequate reproduction of the different gloss levels of a piece of fine art leads to a specular reflection mismatch in printed copies with respect to the original works that affects the perceptual quality of the printout. We used different print parameters of a 3D high resolution printing setup to control the gloss level on a printout locally. Our method can be used to control gloss automatically and in crucial applications such as fine art reproduction.

  6. Fine-grained concrete with organomineral additive

    Directory of Open Access Journals (Sweden)

    Solovyov Vitaly

    2016-01-01

    Full Text Available The article deals with the issues concerning the formation of the structure and properties of fine-grained concrete with organomineral additive produced through mechanochemical activation of thermal power plant fly ash together with superplasticizer. The additive is produced in a high-speed activator at the collision particles’ speed of about 80 m/s. The use of the additive in fine-grained concrete in the amounts of 0.5-1% increased the strength by 30-50% and reduced the size and volume of pores. The cement consumption in such concrete is close to the cement consumption in common concrete of equal resistance.

  7. Dewatering of fine coal using hyperbaric centrifugation

    Energy Technology Data Exchange (ETDEWEB)

    Ramazan Asmatulu; Gerald H. Luttrell; Roe-Hoan Yoon [Virginia Polytechnic Institute and State University, Blacksburg, VA (US). Center for Advanced Separation Technologies

    2005-09-01

    Many coal preparation plants are forced to discard their fine coal because of the inability of existing technologies to reduce the moisture content of this product to an acceptable level. In an effort to overcome this problem, a new mechanical dewatering method has been developed that combines centrifugation with pressure filtration. The process, which may be referred to as hyperbaric centrifugation, is capable of producing a drier product than can be achieved using either filtration or centrifugation alone. The test data obtained from batch experiments show that the new method can reduce cake moisture to 10% or below for many fine coal product streams.

  8. Synthesis of LiBOB Fine Powder to Increase Solubility

    Directory of Open Access Journals (Sweden)

    Etty Marti Wigayati

    2017-04-01

    Full Text Available Lithium bis (oxalate borate or LiBOB compound has captured interest of researchers, because it is potentially viable to be used as electrolyte salt in lithium-ion battery system. This compound is easy to synthesize and considered to be more environmentally friendly compared to conventional electrolyte salt because LiBOB does not contain halogen element. This research focused on the synthesis of LiBOB fine powder, which main purpose is improving LiBOB salt solubility in liquid electrolyte solution. This will aid the ion transfer between electrodes which in turn will increase the electrolyte performance. Solid state reaction was employed in this experiment. Synthesis of LiBOB compound was performed by reacting oxalic acid dihydrate, lithium hydroxide monohydrate, and boric acid. The resulting powder was then processed into fine powder using ball milling technique with varying milling time (0, 6, 10, and 13 hour. Microstructure of the sample was then analyzed to obtain information regarding phase formation, functional groups, grain surface morphology, surface area, pore volume, solubility, and ionic conductivity. The analysis shown that LiBOB and LiBOB hydrate phase was formed during the reaction, there was no changed in existing phase during milling process, crystallinity index was shifted to lower value but there was no difference in functional groups. Highest value in surface area was found to be 83.11 m2/g, with pore volume of 1.21311e+02 A at 10 hours milling. Smaller powder size resulted in higher solubility, unfortunately the ionic conductivity was found to be decreased.

  9. CONTACT STRENGTH OF MECHANOACTIVATED FINE CONCRETES FROM GRANULATED BLAST-FURNACE SLAGS

    Directory of Open Access Journals (Sweden)

    V. I. Bolshakov

    2014-10-01

    Full Text Available Purpose. Strengthening of fine concrete contact zone by mechanical processing of all components of the concrete mix in a mixer-activator and aggregate application with rough surface. Methodology. Rotary activator PC-06, developed by Scientific and Research Institute of Construction Technology, was used as a mixer-activator to achieve this purpose. Granulated blast furnace slag, having a more developed rough surface than sand, was used as fine aggregate. This apparatus provides intensive homogeneous mixing of concrete mix components, processing of raw materials (purification of their particles from contaminants, and mechanical destruction of granulated blast furnace slag surface layers and other components of the mix. Findings. During the preparation work, experimental research of new formations composition of fine concretes, using differential thermal and x-ray phase analysis methods, and physical-mechanical properties of fine concretes in accordance with the applicable standards of Ukraine, were carried out. It is established that the phase composition of new formations of fine concretes made from activated and non-activated mixes, is not changed. Their main difference is the size of generated effects and temperature intervals of occurrence of these peaks. Thus, in fine concretes made on the basis of the activated mixes, magnitude of effects is less, indicating a higher hydration degree of its components. Besides, TG curves of concrete specimens show that weight loss of gel calcium hydrosilicate of concrete from a mechanically activated mix is 0.5...0.7 % more than of concrete from a non-activated mix, which indicates a larger number of these formations in concrete from activated mixes. In general, concretes of different composition, made from a mix, processed in the mixer-activator, have higher mechanical strength. Originality. Ideas about the influence of mechanical activation of components of fine concrete mixes with forming humidity in a

  10. Characterization of Martian Soil Fines Fraction in SNC Meteorites

    Science.gov (United States)

    Rao, M. N.; McKay, D. S.

    2003-01-01

    Some impact-melt glasses in shergottite meteorites contain large abundances of martian atmospheric noble gases with high (129)Xe/(132)Xe ratios, accompanied by varying (87)Sr/(86)Sr (initial) ratios. These glasses contain Martian Soil Fines (MSF) probably from young volcanic terrains such as Tharsis or Elysium Mons. The composition of the MSF bearing samples is different from the average bulk composition of the host rock. These samples show the following charecteristics: a) simultaeneous enrichment of the felsic component and depletion of the mafic component relative to the host phase and b) significant secondary sulfur/sulfate excesses over the host material. The degree of enrichment and associated depletion varies from one sample to another. Earlier, we found large enrichments of felsic (Al, Ca, Na and K) component and depletion of mafic (Fe, Mg, Mn and Ti) component in several impact melt glass veins and pods of samples ,77 ,78 , 18, and ,20A in EET79001 accompanied by large sulfur/sulfate excesses. Based on these results, we proposed a model where the comminution of basaltic rocks takes place by meteoroid bombardment on the martian surface, leading to the generation of fine-grained soil near the impact sites. This fine-grained soil material is subsequently mobilized by saltation and deflation processes on Mars surface due to pervasive aeolian activity. This movement results in mechanical fractionation leading to the felsic enrichment and mafic depletion in the martian dust. We report, here, new data on an impact-melt inclusion ,507 (PAPA) from EET79001, Lith B and ,506 (ALPHA) from EET79001, Lith A and compare the results with those obtained on Shergotty impact melt glass (DBS).

  11. Pollution Standards, Costly Monitoring and Fines

    NARCIS (Netherlands)

    Arguedas, C.

    2005-01-01

    We investigate the features of optimal regulatory policies composed of pollution standards and probabilities of inspection, where fines for non-compliance depend not only on the degree of violation but alson on nongravity factors.We show that optimal policies can induce either compliance or noncompl

  12. Testing with fine fragrances in eczema patients

    DEFF Research Database (Denmark)

    Johansen, J D; Frosch, Peter J; Rastogi, Suresh Chandra

    2001-01-01

    The frequencies of contact allergic reactions to 2 fine fragrances were studied by patch testing. Further, a comparison was made of test results before and after evaporation of the solvent. A total of 480 consecutive eczema patients were included, 100 in the Dortmund clinic and 380 in the Gentoft...

  13. The fine structure of the ionosphere

    DEFF Research Database (Denmark)

    D'Angelo, N.; Michelsen, Poul

    1967-01-01

    We consider in this note the excitation of ion-acoustic waves by vertical gradients of density in the ionosphere. The conclusion is reached that the fine structure of the ionosphere is probably affected by the resulting instability, as comparison with observations seems to indicate. Recently, Liu...

  14. Alkaline Hydrolysis Conversion of Nitrocellulose Fines

    Science.gov (United States)

    1997-10-01

    The conversion of 1,125,000 pounds of bone-dry nitrocellulose fines into a liquid fertilizer was documented. Alkaline hydrolysis was the conversion... fertilizer . Fertilizer nutrient value was 1.3% nitrogen (N), 8.0% potassium (K2O) and 0.9% phosphorus (P2O5). Conversion met all applicable federal and state safety and environmental regulations.

  15. Pollution Standards, Costly Monitoring and Fines

    NARCIS (Netherlands)

    Arguedas, C.

    2005-01-01

    We investigate the features of optimal regulatory policies composed of pollution standards and probabilities of inspection, where fines for non-compliance depend not only on the degree of violation but alson on nongravity factors.We show that optimal policies can induce either compliance or

  16. Fine fuel heating by radiant flux

    Science.gov (United States)

    David Frankman; Brent W. Webb; Bret W. Butler; Don J. Latham

    2010-01-01

    Experiments were conducted wherein wood shavings and Ponderosa pine needles in quiescent air were subjected to a steady radiation heat flux from a planar ceramic burner. The internal temperature of these particles was measured using fine diameter (0.076mm diameter) type K thermocouples. A narrow angle radiometer was used to determine the emissive power generated by the...

  17. The fine structure constant and habitable planets

    DEFF Research Database (Denmark)

    Sandora, McCullen

    2016-01-01

    © 2016 IOP Publishing Ltd and Sissa Medialab srl .We use the existence of habitable planets to impose anthropic requirements on the fine structure constant, α. To this effect, we present two considerations that restrict its value to be very near the one observed. The first, that the end product...

  18. Facilities Guidelines for Fine Arts Programs.

    Science.gov (United States)

    Maryland State Dept. of Education, Baltimore.

    This manual of facility guidelines examines the planning process and design features and considerations for public school fine arts programs in Maryland. Planning concepts and trends are highlighted followed by planning guidelines for dance, music, theater, visual arts, general education, and performance spaces. General design considerations…

  19. Approximation properties of fine hyperbolic graphs

    Indian Academy of Sciences (India)

    Benyin Fu

    2016-05-01

    In this paper, we propose a definition of approximation property which is called the metric invariant translation approximation property for a countable discrete metric space. Moreover, we use the techniques of Ozawa’s to prove that a fine hyperbolic graph has the metric invariant translation approximation property.

  20. Fine structures of type III radio bursts observed by LOFAR

    Science.gov (United States)

    Magdalenic, Jasmina; Marque, Christophe; Fallows, Richard; Mann, Gottfried; Vocks, Christian

    2017-04-01

    On August 25, 2014, NOAA AR 2146 produced the M2.0 class flare (peaked at 15:11 UT). The flare was associated with a coronal dimming, a EUV wave, a halo CME and a radio event observed by LOFAR (the LOw-Frequency Array). The radio event consisted of a type II, type III and type IV radio emissions. In this study, we focus on LOFAR observations of the type III bursts, generally considered to be radio signatures of fast electron beams propagating along open or quasi open field lines. The group of type III bursts was, as usually, observed during the impulsive phase of the flare. At first hand, type III bursts show no peculiarity, but the high frequency/time resolution LOFAR observations reveal that only few of these type III bursts have a smooth emission profile. The majority of bursts is strongly fragmented. Some show a structuring similar to type IIIb bursts, but on a smaller frequency scale, and others show a non-organized patchy structure which gives indication on the possibly related turbulence processes. Although fine structures of type III bursts were already reported, the wealth of fine structures, and the fragmentation of the radio emission observed in this August 25 event is unprecedented. We show that these LOFAR observations bring completely new insight and pose a new challenge for the physics of the acceleration of electron beams and associated emission processes.

  1. Supercritical fluid molecular spray thin films and fine powders

    Science.gov (United States)

    Smith, Richard D.

    1988-01-01

    Solid films are deposited, or fine powders formed, by dissolving a solid material into a supercritical fluid solution at an elevated pressure and then rapidly expanding the solution through a short orifice into a region of relatively low pressure. This produces a molecular spray which is directed against a substrate to deposit a solid thin film thereon, or discharged into a collection chamber to collect a fine powder. The solvent is vaporized and pumped away. Solution pressure is varied to determine, together with flow rate, the rate of deposition and to control in part whether a film or powder is produced and the granularity of each. Solution temperature is varied in relation to formation of a two-phase system during expansion to control porosity of the film or powder. A wide variety of film textures and powder shapes are produced of both organic and inorganic compounds. Films are produced with regular textural feature dimensions of 1.0-2.0 .mu.m down to a range of 0.01 to 0.1 .mu.m. Powders are formed in very narrow size distributions, with average sizes in the range of 0.02 to 5 .mu.m.

  2. Fine root production at drained peatland sites

    Energy Technology Data Exchange (ETDEWEB)

    Finer, L. [Finnish Forest Research Inst. (Finland). Joensuu Research Station; Laine, J. [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    The preliminary results of the Finnish project `Carbon balance of peatlands and climate change` show that fine roots play an important role in carbon cycling on peat soils. After drainage the roots of mire species are gradually replaced by the roots of trees and other forest species. Pine fine root biomass reaches a maximum level by the time of crown closure, some 20 years after drainage on pine mire. The aim of this study is to compare the results of the sequential coring method and the ingrowth bag method used for estimating fine root production on three drained peatland sites of different fertility. The results are preliminary and continuation to the work done in the study Pine root production on drained peatlands, which is part of the Finnish project `Carbon cycling on peatlands and climate change`. In this study the fine root biomass was greater on the poor site than on the rich sites. Pine fine root production increased with the decrease in fertility. Root turnover and the production of field layer species were greater on the rich sites than on the poor site. The results suggested that the in growth bag method measured more root activity than the magnitude of production. More than two growing seasons would have been needed to balance the root dynamics in the in growth bags with the surrounding soil. That time would probably have been longer on the poor site than on the rich ones and longer for pine and field layer consisting of dwarf shrubs than for field layer consisting of sedge like species and birch. (11 refs.)

  3. [The analysis for silver iodide fine particles of TLC/FTIR matrix].

    Science.gov (United States)

    Zhu, Qing; Su, Xiao; Wu, Hai-Jun; Zhai, Yan-Jun; Xia, Jin-Ming; Buhebate; Xu, Yi-Zhuang; Wu, Jin-Guang

    2012-07-01

    In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase has strong absorption in FTIR spectrum and thus brings about severe interference in the detection of samples. To solve the problem, the authors propose to use AgI fine particles as stationary phase of TLC plate. The reasons are as follows: Silver iodide fine particles have no absorbance in an IR region between 4 000 and 800 cm(-1), therefore, the interference caused by IR absorption of stationary phase can be removed. Moreover, silver iodide is stable and insolvable in water and organic solvents and thus it will not be destroyed by mobile phase or react with samples during the TLC separation. To improve TLC separation efficiency and quality of FTIR spectra during the TLC/FTIR analysis, the size of AgI particles should be below 500 nm. We used orthogonal design approach to optimize the experimental condition to AgI particles so that the average size of AgI particles is around 100 nm. No absorption of impurity or adsorbed water were observed in FTIR spectrum of the AgI particles the authors used "settlement volatilization method" to prepare TLC plate without using polymeric adhesive that may bring about significant interference in FTIR analysis. Preliminary TLC experiments proved that the TLC plate using AgI fine particles as stationary phase can separate mixtures of rhodamine B and bromophenol blue successfully. Applications of silver iodide fine particles as stationary phase have bright perspective in the development of in-situ TLC/FTIR analysis techniques.

  4. Olivine and Pyroxene Compositions in Fine-Grained Chondritic Materials

    Science.gov (United States)

    Zolensky, Michael E.; Frank, D.

    2011-01-01

    Our analyses of the Wild-2 samples returned by the Stardust Mission have illuminated critical gaps in our understanding of related astromaterials. There is a very large database of olivine and low-calcium pyroxene compositions for coarse-grained components of chondrites, but a sparse database for anhydrous silicate matrix phases. In an accompanying figure, we present comparisons of Wild-2 olivine with the available chondrite matrix olivine major element data. We thus have begun a long-term project measuring minor as well as major element compositions for chondrite matrix and chondritic IDPs, and Wild 2 grains. Finally, we wish to re-investigate the changes to fine-grained olivine and low-Ca pyroxene composition with progressive thermal metamorphism. We have examined the LL3-4 chondrites which because of the Hayabusa Mission have become very interesting.

  5. TEM and HREM study on the fine structure and the interfacial structure of bainite

    Institute of Scientific and Technical Information of China (English)

    李凤照; 敖青; 顾英妮; 姜江; 孙东升; 戴吉岩; 彭红樱

    1996-01-01

    The fine structure of bainite,the morphology and distribution of carbide in steels and the morphology of bainite in Cu-Zn-Al alloys have been investigated with TEM.The interfacial structure ledges and interfacial crystal lattice images of Cu-Zn-Al alloys have also been investigated with HREM.The addition of alloying microelements can fine the structure of bainitic ferrite markedly.The bainitic ferrite is composed of subunits or subchunks.The carbides differ in morphologies and are distributed in between laths,inside the plates and on the boundaries of subunits.There are abundant fine structures in bainitic ferrite.In the primary bainite of Cu-Zn-Al alloy there are interfacial structure ledges,the height of which is about 3 -40 nm,equal to 15-200 atomic layers.The phase transformation mechanism of bainite is discussed.

  6. DEVELOPMENT AND DEMONSTRATION OF INTEGRATED CARBON RECOVERY SYSTEMS FROM FINE COAL PROCESSING WASTE

    Energy Technology Data Exchange (ETDEWEB)

    Y.P. Chugh; D. Patil; A. Patwardhan; R.Q. Honaker; B.K. Parekh; D. Tao; Latif Khan

    2000-07-01

    The project involves the development of an efficient, environmentally friendly system for the economical recovery of carbon from fine-coal refuse ponds. The project will be conducted in two phases. Phase I was involved in the development and evaluation of process equipment and techniques to be used in carbon recovery, product dewatering and reconstitution, and refuse management. Phase II will integrate the various units into a continuously operating circuit that will be demonstrated at a site selected based on the results presented in this study.

  7. Phases and Phase Transitions

    Science.gov (United States)

    Gitterman, Moshe

    2014-09-01

    In discussing phase transitions, the first thing that we have to do is to define a phase. This is a concept from thermodynamics and statistical mechanics, where a phase is defined as a homogeneous system. As a simple example, let us consider instant coffee. This consists of coffee powder dissolved in water, and after stirring it we have a homogeneous mixture, i.e., a single phase. If we add to a cup of coffee a spoonful of sugar and stir it well, we still have a single phase -- sweet coffee. However, if we add ten spoonfuls of sugar, then the contents of the cup will no longer be homogeneous, but rather a mixture of two homogeneous systems or phases, sweet liquid coffee on top and coffee-flavored wet sugar at the bottom...

  8. FLUIDIZATION OF FINE POWDERS IN FLUIDIZED BEDS WITH AN UPWARD OR A DOWNWARD AIR JET

    Institute of Scientific and Technical Information of China (English)

    Ruoyu Hong; Jianmin Ding; Hongzhong Li

    2005-01-01

    The hydrodynamic behavior of fine powders in jet-fluidized beds was studied numerically and experimentally. The starting point of numerical simulation was the generalized Navier-Stokes (N-S) equations for the gas and solids phases. The κ-εturbulence model was used for high-speed gas jets in fluidized beds. Computation shows that a suitable turbulence model is necessary to obtain agreement between the simulation and literature experimental data for a high-speed gas jet. The model was applied to simulating the fluidization of fine powders in fluidized beds with an upward or a downward air jet. An empirical cohesion model was obtained by correlating the cohesive force between fine particles using a cohetester. The cohesion model was embedded into the two-fluid model to simulate the fluidization of fine powders in two-dimensional (2-D) beds. To study the fluidization behavior of fine and cohesive powders with a downward jet,experiments were performed in a 2-D bed. Agreement between the computed time-averaged porosity and measured data was obtained. With an upward jet in the bed center, the measured and computed porosities show a dilute central core, especially at very high jet velocities. Based on our experiments and computations, a downward jet located inside the bed is recommended to achieve better mixing and contacting of gas and solids.

  9. Dewatering studies of fine clean coal

    Energy Technology Data Exchange (ETDEWEB)

    Parekh, B.K.

    1991-01-01

    Physical cleaning of ultra-fine coal using an advanced froth flotation technique provides a low ash product, however, the amount of water associated with clean coal is high. Economic removal of water from the froth will be important for commercial applicability of advanced froth flotation processes. The main objective of the present research program is to study and understand the dewatering characteristics of ultra-fine clean coal and to develop the process parameters to effectively reduce the moisture to less than 20 percent in the clean coal product. The research approach under investigation utilizes synergistic effects of metal ions and surfactant to lower the moisture of clean coal using a conventional vacuum dewatering technique. During the last year's effort, it was reported that a combination of metal ion and surfactant provided a 22 percent moisture filter cake.

  10. Interaction between Escherichia coli and lunar fines

    Science.gov (United States)

    Johansson, K. R.

    1983-01-01

    A sample of mature lunar fines (10084.151) was solubilized to a high degree (about 17 percent) by the chelating agent salicylic acid (0.01. M). The neutralized (pH adjusted to 7.0) leachate was found to inhibit the growth of Escherichia coli (ATCC 259922) in a minimial mineral salts glucose medium; however, the inhibition was somewhat less than that caused by neutralized salicylic acid alone. The presence of lunar fines in the minimal medium was highly stimulatory to growth of E. coli following an early inhibitory response. The bacterium survived less well in the lunar leachate than in distilled water, no doubt because of the salicylate. It was concluded that the sample of lunar soil tested has nutritional value to E. coli and that certain products of fermentation helped to solubilize the lunar soil.

  11. Customizing digital printing for fine art practice

    Science.gov (United States)

    Parraman, Carinna E.; Thirkell, Paul; Hoskins, Steve; Wang, Hong Qiang; Laidler, Paul

    2005-01-01

    The presentation will demonstrate how through alternative methods of digital print production the Centre for Fine Print Research (CFPR) is developing methodologies for digital printing that attempt to move beyond standard reproductive print methods. Profiling is used for input and output hardware, along with bespoke profiling for fine art printmaking papers. Examples of artist's work, and examples from the Perpetual Portfolio are included - an artist in residence scheme for selected artists wanting to work at the Centre and to make a large-format digital print. Colour is an important issue: colour fidelity, colour density on paper, colour that can be achieved through multiple-pass printing. Research is also underway to test colour shortfalls in the current inkjet ink range, and to extend colour through the use of traditional printing inks.

  12. Fractal aggregation and breakup of fine particles

    Directory of Open Access Journals (Sweden)

    Li Bingru

    2016-01-01

    Full Text Available Breakup may exert a controlling influence on particle size distributions and particles either are fractured or are eroded particle-by-particle through shear. The shear-induced breakage of fine particles in turbulent conditions is investigated using Taylor-expansion moment method. Their equations have been derived in continuous form in terms of the number density function with particle volume. It suitable for future implementation in computational fluid dynamics modeling.

  13. Process for treating moisture laden coal fines

    Science.gov (United States)

    Davis, Burl E.; Henry, Raymond M.; Trivett, Gordon S.; Albaugh, Edgar W.

    1993-01-01

    A process is provided for making a free flowing granular product from moisture laden caked coal fines, such as wet cake, by mixing a water immiscible substance, such as oil, with the caked coal, preferably under low shear forces for a period of time sufficient to produce a plurality of free flowing granules. Each granule is preferably comprised of a dry appearing admixture of one or more coal particle, 2-50% by weight water and the water immiscible substance.

  14. Alternate Methods for Disposal of Nitrocellulose Fines

    Science.gov (United States)

    1985-07-22

    edition$ are obsolete. UNLSSFE UNCLASSIFIED SECURITY CLASSIPICATION OP THIS PAGE recycled; and, being ubituitous in nature , are not considered...Matrix xomparison of technologies ................. 22 3.4 Ranking and seleccion of technologies ............. 26 4. CONCLUSIONS AND RECOMMENDATIONS 4.1...ubiquitous in nature , are not considered pollutants anyway. There are several "ready technologies" that appear to be capable of removing NC fines more

  15. On a time varying fine structure constant

    CERN Document Server

    Berman, M S; Berman, Marcelo S.; Trevisan, Luis A.

    2001-01-01

    By employing Dirac LNH, and a further generalization by Berman (GLNH), we estimate how should vary the total number of nucleons, the energy density, Newton Gravitational constant, the cosmological constant, the magnetic permeability and electric permitivity, of the Universe,in order to account for the experimentally observed time variation of the fine structure constant. As a bonus,we find an acceptable value for the deceleration parameter of the present Universe, compatible with the Supernovae observations.

  16. Corrosion of surface defects in fine wires.

    Science.gov (United States)

    Rentler, R M; Greene, N D

    1975-11-01

    Defects were observed on the surfaces of various fine diameter wires commonly used in biomedical applications. These surface irregularities were viewed at high magnifications using a scanning electron microscope which has a much greater depth of field than normal light microscopy. Defects include scratches, pits, and crevices, which are the result of commercial wire drawing practices. Corrosion test results show that imperfections can serve as sites for localized corrosion attack which could lead to premature failures.

  17. Sensitivity analysis of fine sediment models using heterogeneous data

    Science.gov (United States)

    Kamel, A. M. Yousif; Bhattacharya, B.; El Serafy, G. Y.; van Kessel, T.; Solomatine, D. P.

    2012-04-01

    Sediments play an important role in many aquatic systems. Their transportation and deposition has significant implication on morphology, navigability and water quality. Understanding the dynamics of sediment transportation in time and space is therefore important in drawing interventions and making management decisions. This research is related to the fine sediment dynamics in the Dutch coastal zone, which is subject to human interference through constructions, fishing, navigation, sand mining, etc. These activities do affect the natural flow of sediments and sometimes lead to environmental concerns or affect the siltation rates in harbours and fairways. Numerical models are widely used in studying fine sediment processes. Accuracy of numerical models depends upon the estimation of model parameters through calibration. Studying the model uncertainty related to these parameters is important in improving the spatio-temporal prediction of suspended particulate matter (SPM) concentrations, and determining the limits of their accuracy. This research deals with the analysis of a 3D numerical model of North Sea covering the Dutch coast using the Delft3D modelling tool (developed at Deltares, The Netherlands). The methodology in this research was divided into three main phases. The first phase focused on analysing the performance of the numerical model in simulating SPM concentrations near the Dutch coast by comparing the model predictions with SPM concentrations estimated from NASA's MODIS sensors at different time scales. The second phase focused on carrying out a sensitivity analysis of model parameters. Four model parameters were identified for the uncertainty and sensitivity analysis: the sedimentation velocity, the critical shear stress above which re-suspension occurs, the shields shear stress for re-suspension pick-up, and the re-suspension pick-up factor. By adopting different values of these parameters the numerical model was run and a comparison between the

  18. ELECTROSTATICALLY SUPPORTED MIXING OF FINE GRAINED PARTICLES

    Institute of Scientific and Technical Information of China (English)

    K.-E.; Wirth; M.; Linsenbühler

    2005-01-01

    The processing of fine-grained particles with diameters between 1 and 10 microns is difficult due to strong van-der-Waals attraction forces. In order to improve the handling properties, the fine-grained particles, i.e. host-particles,are coated with various nanoparticles, i.e. guest-particles. The mixing of fine-grained powders is influenced by particle-particle interactions. If these forces are distinctively used, both interactive and ordered mixtures can be produced.These particle mixtures consist of composite-particles that have new physical properties. These modified properties d epend strongly on the coating process, the diameter- and mass-relationship of the guest- and the host-particles. The properties of the composite-particles can systematically be adjusted to the requirements of industrial applications. For example, a laboratory bubbling fluidized bed can be used to describe the conveying behavior of the functionalized host-particles. Applications for the functionalized particles are in the pharmaceutical and the powder coating industries,e.g. enhanced dry powder inhalers and thin lacquer films. The present research compares three different mixing/coating processes. The composite-particles are characterized by TEM, SEM and with their fluidization characteristics. The coating process itself is monitored by the electrostatic charge of the particles.

  19. Variation of the fine structure constant

    CERN Document Server

    Lipovka, Anton A

    2016-01-01

    In present paper we evaluate the fine structure constant variation which should take place as the Universe is expanded and its curvature is changed adiabatically. This changing of the fine structure constant is attributed to the energy lost by physical system (consist of baryonic component and electromagnetic field) due to expansion of our Universe. Obtained ratio (d alpha)/alpha = 1. 10{-18} (per second) is only five times smaller than actually reported experimental limit on this value. For this reason this variation can probably be measured within a couple of years. To argue the correctness of our approach we calculate the Planck constant as adiabatic invariant of electromagnetic field, from geometry of our Universe in the framework of the pseudo- Riemannian geometry. Finally we discuss the double clock experiment based on Al+ and Hg+ clocks carried out by T. Rosenband et al. (Science 2008). We show that in this particular case there is an error in method and this way the fine structure constant variation c...

  20. Defending The Fallacy of Fine-Tuning

    CERN Document Server

    Stenger, Victor J

    2012-01-01

    In 2011, I published a popular-level book, The Fallacy of Fine-Tuning: Why the Universe is Not Designed for Us. It investigated a common claim found in contemporary religious literature that the parameters of physics and cosmology are so delicately balanced, so "fine-tuned," that any slight change and life in the universe would have been impossible. I concluded that while the precise form of life we find on Earth would not exist with slight changes in these parameters, some form of life could have evolved over a parameter range that is not infinitesimal, as often claimed. Postdoctoral fellow Luke Barnes has written a lengthy, highly technical review [arXiv:1112.4647] of the scientific literature on the fine-tuning problem. I have no significant disagreement with that literature and no prominent physicist or cosmologist has disputed my basic conclusions. Barnes does not invalidate these conclusions and misunderstands and misrepresents much of what is in the book.

  1. RSW Fully Tet Cell-Centered Fine Mesh

    Data.gov (United States)

    National Aeronautics and Space Administration — This is the RSW dataset for a fine fully tetrahedral grid designed for a cell-centered unstructured solver. UG3 : Grid File Name = rsw_fine_tetcc.b8.ugrid UG3 : Quad...

  2. Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid ... Needle Aspiration Biopsy of the Thyroid? What is Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid? ...

  3. INVESTIGATIONS INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES

    Science.gov (United States)

    Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. Fine pore diffusers were obtained from five municipal wastewa...

  4. Identifying fine sediment sources to alleviate flood risk caused by fine sediments through catchment connectivity analysis

    Science.gov (United States)

    Twohig, Sarah; Pattison, Ian; Sander, Graham

    2017-04-01

    Fine sediment poses a significant threat to UK river systems in terms of vegetation, aquatic habitats and morphology. Deposition of fine sediment onto the river bed reduces channel capacity resulting in decreased volume to contain high flow events. Once the in channel problem has been identified managers are under pressure to sustainably mitigate flood risk. With climate change and land use adaptations increasing future pressures on river catchments it is important to consider the connectivity of fine sediment throughout the river catchment and its influence on channel capacity, particularly in systems experiencing long term aggradation. Fine sediment erosion is a continuing concern in the River Eye, Leicestershire. The predominately rural catchment has a history of flooding within the town of Melton Mowbray. Fine sediment from agricultural fields has been identified as a major contributor of sediment delivery into the channel. Current mitigation measures are not sustainable or successful in preventing the continuum of sediment throughout the catchment. Identifying the potential sources and connections of fine sediment would provide insight into targeted catchment management. 'Sensitive Catchment Integrated Modelling Analysis Platforms' (SCIMAP) is a tool often used by UK catchment managers to identify potential sources and routes of sediment within a catchment. SCIMAP is a risk based model that combines hydrological (rainfall) and geomorphic controls (slope, land cover) to identify the risk of fine sediment being transported from source into the channel. A desktop version of SCIMAP was run for the River Eye at a catchment scale using 5m terrain, rainfall and land cover data. A series of SCIMAP model runs were conducted changing individual parameters to determine the sensitivity of the model. Climate Change prediction data for the catchment was used to identify potential areas of future connectivity and erosion risk for catchment managers. The results have been

  5. Fine particle emissions from residential wood combustion

    Energy Technology Data Exchange (ETDEWEB)

    Tissari, J.

    2008-07-01

    Residential wood combustion (RWC) appliances have the high probability of incomplete combustion, producing e.g. fine particles and hazardous organic compounds. In this thesis, the fine particle number and mass emissions, particle composition and morphology, and gas emissions were investigated from the modern (MMH) and conventional masonry heaters (CMH), sauna stoves (SS) and pellet burner. The investigation was based on laboratory and field experiments applying extensive and unique particle sampling methods. The appliance type, fuel and operational practices were found to affect clearly the fine particle emissions. In good combustion conditions (e.g. in pellet combustion), the fine particle mass (PM{sub 1}) emission factors were low, typically below 0.3 g kg-1, and over 90% of the PM{sub 1} consisted of inorganic compounds (i.e fine ash). From the CMH the typical PM{sub 1} values were 1.6-1.8 g kg-1, and from the SS 2.7-5.0 g kg-1, but were strongly dependent on operational practices. The smouldering combustion in CMH increased PM{sub 1} emission up to 10 g kg-1. The good secondary combustion in the MMH reduced the particle organic matter (POM) and gaseous emissions, but not substantially the elemental carbon (EC, i.e. soot) emission, and the typical PM{sub 1} values were 0.7-0.8 g kg-1. The particle number emissions were high, and did not correspond with the completition of combustion. The particle number distributions were mainly dominated by ultrafine (<100 nm) particles, but varied dependent on combustion conditions. The electronmicroscopy analyses showed that ultrafine particles were composed mainly of K, S and Zn. From the smouldering combustion, particles were composed mainly of carbon compounds and they had a closed sinteredlike structure, due to organic matter on the particles. Controlling the gasification rate via the primary air supply, log and batch size, as well as fuel moisture content, is important for the reduction of emissions in batch combustion

  6. Influence of fine sediment on the fluidity of debris flows

    OpenAIRE

    HOTTA, Norifumi; Kaneko, Takahiro; Iwata, Tomoyuki; Nishimoto, Haruo

    2013-01-01

    Debris flows include a great diversity of grain sizes with inherent features such as inverse grading, particle size segregation, and liquefaction of fine sediment. The liquefaction of fine sediment affects the fluidity of debris flows, although the behavior and influence of fine sediment in debris flows have not been examined sufficiently. This study used flume tests to detect the effect of fine sediment on the fluidity of laboratory debris flows consisting of particles with various diameters...

  7. Development of an Ultra-fine Coal Dewatering Technology and an Integrated Flotation-Dewatering System for Coal Preparation Plants

    Energy Technology Data Exchange (ETDEWEB)

    Wu Zhang; David Yang; Amar Amarnath; Iftikhar Huq; Scott O' Brien; Jim Williams

    2006-12-22

    The project proposal was approved for only the phase I period. The goal for this Phase I project was to develop an industrial model that can perform continuous and efficient dewatering of fine coal slurries of the previous flotation process to fine coal cake of {approx}15% water content from 50-70%. The feasibility of this model should be demonstrated experimentally using a lab scale setup. The Phase I project was originally for one year, from May 2005 to May 2006. With DOE approval, the project was extended to Dec. 2006 without additional cost from DOE to accomplish the work. Water has been used in mining for a number of purposes such as a carrier, washing liquid, dust-catching media, fire-retardation media, temperature-control media, and solvent. When coal is cleaned in wet-processing circuits, waste streams containing water, fine coal, and noncombustible particles (ash-forming minerals) are produced. In many coal preparation plants, the fine waste stream is fed into a series of selection processes where fine coal particles are recovered from the mixture to form diluted coal fine slurries. A dewatering process is then needed to reduce the water content to about 15%-20% so that the product is marketable. However, in the dewatering process currently used in coal preparation plants, coal fines smaller than 45 micrometers are lost, and in many other plants, coal fines up to 100 micrometers are also wasted. These not-recovered coal fines are mixed with water and mineral particles of the similar particle size range and discharged to impoundment. The wasted water from coal preparation plants containing unrecoverable coal fine and mineral particles are called tailings. With time the amount of wastewater accumulates occupying vast land space while it appears as threat to the environment. This project developed a special extruder and demonstrated its application in solid-liquid separation of coal slurry, tailings containing coal fines mostly less than 50 micron. The

  8. Development of fine motor skills in preterm infants

    NARCIS (Netherlands)

    Bos, Arend F.; Van Braeckel, Koenraad N. J. A.; Hitzert, Marrit M.; Tanis, Jozien C.; Roze, Elise

    2013-01-01

    Fine motor skills are related to functioning in daily life and at school. We reviewed the status of knowledge, in preterm children, on the development of fine motor skills, the relation with gross motor skills, and risk factors for impaired fine motor skills. We searched the past 15 years in PubMed,

  9. Crystallization and Microstructure of Li2O-Al2O3-SiO2 Glass-ceramics Produced with Environmentally Acceptable Fining Agents

    Institute of Scientific and Technical Information of China (English)

    GUO; Xingzhong; CAI; Xiaobo; SONG; Jie; YANG; Hui

    2015-01-01

    Lithium aluminosilicate(LAS) glass-ceramics with a few gas bubbles were prepared when SnO2, V2O5 and CeO2 were used as fining agents. The effect of the complex fining agent on the crystallization, phase compositions and microstructure of LAS glass–ceramics was investigated by differential thermal analysis, X-ray diffraction and scanning electron microscopy, respectively. The results show that the introduction of fining agents promotes the crystallization at a lower temperature and has little effect on the compositions of main crystalline phase and microstructure when the crystalline phase remains β-quartz. The special colors of LAS glass-ceramics can be obtained by controlling the crystallization temperature and the amounts of V2O5 and CeO2. The complex fining agent is an environmentally friendly alternative to toxic As2O3 and can be also used as a colorant for colored LAS glass-ceramics.

  10. Optimization of calcium phosphate fine ceramic powders preparation

    Science.gov (United States)

    Sezanova, K.; Tepavitcharova, S.; Rabadjieva, D.; Gergulova, R.; Ilieva, R.

    2013-12-01

    The effect of biomimetic synthesis method, reaction medium and further precursor treatments on the chemical and phase composition, crystal size and morphology of calcium phosphates was examined. Nanosized calcium phosphate precursors were biomimetically precipitated by the method of continuous precipitation in three types of reaction media at pH 8: (i) SBF as an inorganic electrolyte system; (ii) organic (glycerine) modified SBF (volume ratio of 1:1); (iii) polymer (10 g/l xanthan gum or 10 g/l guar gum) modified SBF (volume ratio of 1:1). After maturation (24 h) the samples were lyophilized, calcinated at 300°C for 3 hours, and washed with water, followed by new gelation, lyophilization and step-wise (200, 400, 600, 800, and 1000°C, each for 3 hours) sintering. The reaction medium influenced the chemical composition and particle size but not the morphology of the calcium phosphate powders. In all studied cases bi-phase calcium phosphate fine powders with well-shaped spherical grains, consisting of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) with a Ca/P ratio of 1.3 - 1.6 were obtained. The SBF modifiers decreased the particle size of the product in the sequence guar gum ˜ xanthan gum < glycerin < SBF medium.

  11. Laser Indirect Shock Welding of Fine Wire to Metal Sheet.

    Science.gov (United States)

    Wang, Xiao; Huang, Tao; Luo, Yapeng; Liu, Huixia

    2017-09-12

    The purpose of this paper is to present an advanced method for welding fine wire to metal sheet, namely laser indirect shock welding (LISW). This process uses silica gel as driver sheet to accelerate the metal sheet toward the wire to obtain metallurgical bonding. A series of experiments were implemented to validate the welding ability of Al sheet/Cu wire and Al sheet/Ag wire. It was found that the use of a driver sheet can maintain high surface quality of the metal sheet. With the increase of laser pulse energy, the bonding area of the sheet/wire increased and the welding interfaces were nearly flat. Energy dispersive spectroscopy (EDS) results show that the intermetallic phases were absent and a short element diffusion layer which would limit the formation of the intermetallic phases emerging at the welding interface. A tensile shear test was used to measure the mechanical strength of the welding joints. The influence of laser pulse energy on the tensile failure modes was investigated, and two failure modes, including interfacial failure and failure through the wire, were observed. The nanoindentation test results indicate that as the distance to the welding interface decreased, the microhardness increased due to the plastic deformation becoming more violent.

  12. Sexual recombination in Colletotrichum lindemuthianum occurs on a fine scale.

    Science.gov (United States)

    Souza, E A; Camargo, O A; Pinto, J M A

    2010-09-08

    Glomerella cingulata f. sp phaseoli is the sexual phase of the fungus Colletotrichum lindemuthianum, the causal agent of common bean anthracnose. This fungus is of great concern, because it causes large economic losses in common bean crops. RAPD markers of five populations of G. cingulata f. sp phaseoli from two Brazilian states were analyzed to determine if this population possesses the sexual reproductive potential to generate the genetic variation that is observed in this phytopathogen. We identified 128 polymorphic bands, amplified by 28 random primers. The estimates of genetic similarity in this analysis ranged from 0.43 to 1.00, and the dendrogram generated from analysis of all genotypes displayed five principal groups, coinciding with the five populations. Genetic differentiation was observed between the populations (GST=0.6455); 69% of the overall observed genetic variation was between individual populations and 31% of the variance was within the sub-populations. We identified significant levels of linkage disequilibrium in all populations. However, the values of the disequilibrium ranged from low to moderate, indicating that this pathogen maintains a genetic structure consistent with sexual reproduction. The mean contribution of sexual reproduction was determined by comparison of the amplitudes of genetic similarity of isolates from sexual and asexual phases. These results support the hypothesis that recombination plays an important role in determining the amplitude of variability in this pathogen population and that this determination occurs on a fine scale.

  13. Enhancement of biodegradation of oil adsorbed on fine soils in a bioslurry reactor

    OpenAIRE

    Okuda, Tetsuji; Alcantara-Garduno, Martha E.; Suzuki, Masahiro; Matsui, Chikara; Kose, Tomohiro; Nishijima, Wataru; Okada, Mitsumasa

    2007-01-01

    Techniques for enhancing the biodegradation of oil-contaminated fine soils in a slurry-phase bioreactor were investigated. Using a model system consisting of kaolin particles containing adsorbed n-dodecane as a diesel fuel surrogate, we investigated how increasing the temperature and adding a surfactant and various hydrophobic support media affected the biodegradation rate of n-dodecane. Increasing the temperature from 25 to 35°C decreased the time required for complete degradation of n-dodec...

  14. Frontiers in Sedimentary Geology: Microstructure of Fine-Grained Sediments from Mud to Shale

    Science.gov (United States)

    1990-01-01

    Sediment in Response to Periodic D eposition ............................................... 417 Charles Libicki and Keith W Bedford 46 Elasticity of Fine...Division, Naval Ocean Research and Development Activity, Stennis Space Center, MS 39529-5004, USA CHARLES LIBICKI. Department of Civil Engineering, The...depositional waters" (Curtis, 1985, pp. 91-92). Diagencsi, of mineral phases and cementation operate over a Dunoyer De Segonzac (1970) pointed out that

  15. Improvement in SOFC anode performance by finely-structured Ni/YSZ cermet prepared via heterocoagulation.

    Science.gov (United States)

    Sunagawa, Yoji; Yamamoto, Katsutoshi; Muramatsu, Atsushi

    2006-03-30

    A novel preparation technique for a nanostructured anode for a solid oxide fuel cell is investigated. By mixing nanometer-sized NiO and YSZ powders in a pH-controlled aqueous media, a fine mixture of nanoparticles is successfully obtained through heterocoagulation. The anode prepared from thus prepared mixture has a large triple phase boundary and shows a great improvement in the anode performance by increasing the electric conductivity and effective surface area.

  16. GeneRecon—A coalescent based tool for fine-scale association mapping

    DEFF Research Database (Denmark)

    Mailund, Thomas; Schierup, Mikkel Heide; Pedersen, Christian Nørgaard Storm

    2006-01-01

    GeneRecon is a tool for fine-scale association mapping using a coalescence model. GeneRecon takes as input case-control data from phased or unphased SNP and micro-satellite genotypes. The posterior distribution of disease locus position is obtained by Metropolis Hastings sampling in the state space...... of genealogies. Input format, search strategy, and the sampled statistics can be configured through the Guile Scheme programming language embedded in GeneRecon, making GeneRecon highly configurable....

  17. Fine structure of synapses on dendritic spines

    Directory of Open Access Journals (Sweden)

    Michael eFrotscher

    2014-09-01

    Full Text Available Camillo Golgi’s Reazione Nera led to the discovery of dendritic spines, small appendages originating from dendritic shafts. With the advent of electron microscopy (EM they were identified as sites of synaptic contact. Later it was found that changes in synaptic strength were associated with changes in the shape of dendritic spines. While live-cell imaging was advantageous in monitoring the time course of such changes in spine structure, EM is still the best method for the simultaneous visualization of all cellular components, including actual synaptic contacts, at high resolution. Immunogold labeling for EM reveals the precise localization of molecules in relation to synaptic structures. Previous EM studies of spines and synapses were performed in tissue subjected to aldehyde fixation and dehydration in ethanol, which is associated with protein denaturation and tissue shrinkage. It has remained an issue to what extent fine structural details are preserved when subjecting the tissue to these procedures. In the present review, we report recent studies on the fine structure of spines and synapses using high-pressure freezing (HPF, which avoids protein denaturation by aldehydes and results in an excellent preservation of ultrastructural detail. In these studies, HPF was used to monitor subtle fine-structural changes in spine shape associated with chemically induced long-term potentiation (cLTP at identified hippocampal mossy fiber synapses. Changes in spine shape result from reorganization of the actin cytoskeleton. We report that cLTP was associated with decreased immunogold labeling for phosphorylated cofilin (p-cofilin, an actin-depolymerizing protein. Phosphorylation of cofilin renders it unable to depolymerize F-actin, which stabilizes the actin cytoskeleton. Decreased levels of p-cofilin, in turn, suggest increased actin turnover, possibly underlying the changes in spine shape associated with cLTP. The findings reviewed here establish HPF as

  18. Leeuwpan fine coal dense medium plant

    CSIR Research Space (South Africa)

    Lundt, M

    2010-11-01

    Full Text Available availability to treat the higher grade coal (the bottom layer of coal) from the no. 2 Seam for a local and export metallurgical market. Following the path of evolution, in 2007, Leeuwpan commissioned the first double stage ultra-fines dense medium cyclone... plant in the coal industry, to form part of its overall DMS plant. It replaced the spirals to treat the -1 mm material. Spirals are still the most commonly and accepted method used by the industry, but it seems as if the pioneering cyclone process...

  19. Fine Structure Constant: Theme With Variations

    CERN Document Server

    Bezerra, V B; Muniz, C R; Tahim, M O; Vieira, H S

    2016-01-01

    In this paper, we study the spatial variation of the fine structure constant $\\alpha$ due to the presence of a static and spherically symmetric gravitational source. The procedure consists of calculating the solution including the energy eigenvalues of a massive scalar field around that source, considering the weak-field regimen, which yields the gravitational analog of the atomic Bohr levels. From this result, we obtain several values for the effective $\\alpha$ by considering some scenarios of semi-classical and quantum gravities. Constraints on the parameters of the involved theories are calculated from astrophysical observations of the white dwarf emission spectra. Such constraints are compared with those ones obtained in the literature.

  20. Computer Models Simulate Fine Particle Dispersion

    Science.gov (United States)

    2010-01-01

    Through a NASA Seed Fund partnership with DEM Solutions Inc., of Lebanon, New Hampshire, scientists at Kennedy Space Center refined existing software to study the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces. The software, EDEM, allows users to import particles and obtain accurate representations of their shapes for modeling purposes, such as simulating bulk solids behavior, and was enhanced to be able to more accurately model fine, abrasive, cohesive particles. These new EDEM capabilities can be applied in many industries unrelated to space exploration and have been adopted by several prominent U.S. companies, including John Deere, Pfizer, and Procter & Gamble.

  1. Dewatering studies of fine clean coal

    Energy Technology Data Exchange (ETDEWEB)

    Parekh, B.K.

    1991-01-01

    The main objective of the present research program is to study and understand dewatering characteristics of ultrafine clean coal obtained using the advanced column flotation technique from the Kerr-McGee's Galatia preparation plant fine coal waste stream. It is also the objective of the research program to utilize the basic study results, i.e., surface chemical, particle shape particle size distribution, etc., in developing a cost-effective dewatering method. The ultimate objective is to develop process criteria to obtain a dewatered clean coal product containing less that 20 percent moisture, using the conventional vacuum dewatering equipment. (VC)

  2. Planck scale operators, inflation and fine tuning

    CERN Document Server

    Marunovic, Anja

    2016-01-01

    Ultraviolet completion of the standard model plus gravity at and beyond the Planck scale is a daunting problem to which no generally accepted solution exists. Principal obstacles include (a) lack of data at the Planck scale (b) nonrenormalizability of gravity and (c) unitarity problem. Here we make a simple observation that, if one treats all Planck scale operators of equal canonical dimension democratically, one can tame some of the undesirable features of these models. With a reasonable amount of fine tuning one can satisfy slow roll conditions required in viable inflationary models. That remains true even when the number of such operators becomes very large.

  3. A cyclic universe approach to fine tuning

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, Stephon, E-mail: stephon.alexander@dartmouth.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Department of Physics, Brown University, Providence, RI 02906 (United States); Cormack, Sam, E-mail: samuel.c.cormack.gr@dartmouth.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Gleiser, Marcelo, E-mail: marcelo.gleiser@dartmouth.edu [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

    2016-06-10

    We present a closed bouncing universe model where the value of coupling constants is set by the dynamics of a ghost-like dilatonic scalar field. We show that adding a periodic potential for the scalar field leads to a cyclic Friedmann universe where the values of the couplings vary randomly from one cycle to the next. While the shuffling of values for the couplings happens during the bounce, within each cycle their time-dependence remains safely within present observational bounds for physically-motivated values of the model parameters. Our model presents an alternative to solutions of the fine tuning problem based on string landscape scenarios.

  4. The Fine Structure Constant and Habitable Planets

    CERN Document Server

    Sandora, McCullen

    2016-01-01

    We use the existence of habitable planets to impose anthropic requirements on the fine structure constant, $\\alpha$. To this effect, we present two considerations that restrict its value to be very near the one observed. The first, that the end product of stellar fusion is iron and not one of its neighboring elements, restricts $\\alpha^{-1}$ to be $145\\pm 50$. The second, that radiogenic heat in the Earth's interior remains adequately productive for billions of years, restricts it to be $145\\pm9$. A connection with the grand unified theory window is discussed, effectively providing a route to probe ultra-high energy physics with upcoming advances in planetary science.

  5. The fine structure constant and habitable planets

    Science.gov (United States)

    Sandora, McCullen

    2016-08-01

    We use the existence of habitable planets to impose anthropic requirements on the fine structure constant, α. To this effect, we present two considerations that restrict its value to be very near the one observed. The first, that the end product of stellar fusion is iron and not one of its neighboring elements, restricts α-1 to be 145± 50. The second, that radiogenic heat in the Earth's interior remains adequately productive for billions of years, restricts it to be 145±9. A connection with the grand unified theory window is discussed, effectively providing a route to probe ultra-high energy physics with upcoming advances in planetary science.

  6. The fine structure constant and habitable planets

    DEFF Research Database (Denmark)

    Sandora, McCullen

    2016-01-01

    © 2016 IOP Publishing Ltd and Sissa Medialab srl .We use the existence of habitable planets to impose anthropic requirements on the fine structure constant, α. To this effect, we present two considerations that restrict its value to be very near the one observed. The first, that the end product...... of stellar fusion is iron and not one of its neighboring elements, restricts α-1 to be 145± 50. The second, that radiogenic heat in the Earth's interior remains adequately productive for billions of years, restricts it to be 145±9. A connection with the grand unified theory window is discussed, effectively...

  7. Haptic rendering for simulation of fine manipulation

    CERN Document Server

    Wang, Dangxiao; Zhang, Yuru

    2014-01-01

    This book introduces the latest progress in six degrees of freedom (6-DoF) haptic rendering with the focus on a new approach for simulating force/torque feedback in performing tasks that require dexterous manipulation skills. One of the major challenges in 6-DoF haptic rendering is to resolve the conflict between high speed and high fidelity requirements, especially in simulating a tool interacting with both rigid and deformable objects in a narrow space and with fine features. The book presents a configuration-based optimization approach to tackle this challenge. Addressing a key issue in man

  8. Pre - big bang inflation requires fine tuning

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Michael S. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Weinberg, Erick J. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

    1997-10-01

    The pre-big-bang cosmology inspired by superstring theories has been suggested as an alternative to slow-roll inflation. We analyze, in both the Jordan and Einstein frames, the effect of spatial curvature on this scenario and show that too much curvature --- of either sign --- reduces the duration of the inflationary era to such an extent that the flatness and horizon problems are not solved. Hence, a fine-tuning of initial conditions is required to obtain enough inflation to solve the cosmological problems.

  9. Design and Lessons Learned on the Development of a Cryogenic Pupil Select Mechanism Used in the Testing and Calibration of the Integrated Science Instrument Module (ISIM) on the James Webb Space Telescope (JWST)

    Science.gov (United States)

    Mitchell, Alissa; Capon, Thomas; Guzek, Jeffrey; Hakun, Claef; Haney, Paul; Koca, Corina

    2014-01-01

    Calibration and testing of the instruments on the Integrated Science Instrument Module (ISIM) of the James Webb Space Telescope (JWST) is being performed by the use of a cryogenic, full-field, optical simulator that was constructed for this purpose. The Pupil Select Mechanism (PSM) assembly is one of several mechanisms and optical elements that compose the Optical Telescope Element SIMulator, or OSIM. The PSM allows for several optical elements to be inserted into the optical plane of OSIM, introducing a variety of aberrations, distortions, obscurations, and other calibration states into the pupil plane. The following discussion focuses on the details of the design evolution, analysis, build, and test of this mechanism along with the challenges associated with creating a sub arc-minute positioning mechanism operating in an extreme cryogenic environment. In addition, difficult challenges in the control system design will be discussed including the incorporation of closed-loop feedback control into a system that was designed to operate in an open-loop fashion.

  10. Influence of fine water droplets to temperature and humidity

    Science.gov (United States)

    Hafidzal, M. H. M.; Hamzah, A.; Manaf, M. Z. A.; Saadun, M. N. A.; Zakaria, M. S.; Roslizar, A.; Jumaidin, R.

    2015-05-01

    Excessively dry air can cause dry skin, dry eyes and exacerbation of medical conditions. Therefore, many researches have been done in order to increase humidity in our environment. One of the ways is by using water droplets. Nowadays, it is well known in market stand fan equipped with water mister in order to increase the humidity of certain area. In this study, the same concept is applied to the ceiling fan. This study uses a model that combines a humidifier which functions as cooler, ceiling fan and scaled down model of house. The objective of this study is to analyze the influence of ceiling fan humidifier to the temperature and humidity in a house. The mechanism of this small model uses batteries as the power source, connected to the fan and the humidifier. The small water tank's function is to store and supply water to the humidifier. The humidifier is used to cool the room by changing water phase to fine water droplets. Fine water droplets are created from mechanism of the humidifier, which is by increasing the kinetic energy of water molecule using high frequency vibration that overcome the holding force between water molecules. Thus, the molecule of water will change to state of gas or mist. The fan is used to spread out the mist of water to surrounding of the room in order to enhance the humidity. Thermocouple and humidity meter are used to measure temperature and humidity in some period of times. The result shows that humidity increases and temperature decreases with time. This application of water droplet can be applied in the vehicles and engine in order to decrease the temperature.

  11. Method for producing dustless graphite spheres from waste graphite fines

    Science.gov (United States)

    Pappano, Peter J [Oak Ridge, TN; Rogers, Michael R [Clinton, TN

    2012-05-08

    A method for producing graphite spheres from graphite fines by charging a quantity of spherical media into a rotatable cylindrical overcoater, charging a quantity of graphite fines into the overcoater thereby forming a first mixture of spherical media and graphite fines, rotating the overcoater at a speed such that the first mixture climbs the wall of the overcoater before rolling back down to the bottom thereby forming a second mixture of spherical media, graphite fines, and graphite spheres, removing the second mixture from the overcoater, sieving the second mixture to separate graphite spheres, charging the first mixture back into the overcoater, charging an additional quantity of graphite fines into the overcoater, adjusting processing parameters like overcoater dimensions, graphite fines charge, overcoater rotation speed, overcoater angle of rotation, and overcoater time of rotation, before repeating the steps until graphite fines are converted to graphite spheres.

  12. Molecular Eigensolution Symmetry Analysis and Fine Structure

    Directory of Open Access Journals (Sweden)

    William G. Harter

    2013-01-01

    Full Text Available Spectra of high-symmetry molecules contain fine and superfine level cluster structure related to J-tunneling between hills and valleys on rovibronic energy surfaces (RES. Such graphic visualizations help disentangle multi-level dynamics, selection rules, and state mixing effects including widespread violation of nuclear spin symmetry species. A review of RES analysis compares it to that of potential energy surfaces (PES used in Born-Oppenheimer approximations. Both take advantage of adiabatic coupling in order to visualize Hamiltonian eigensolutions. RES of symmetric and D2 asymmetric top rank-2-tensor Hamiltonians are compared with Oh spherical top rank-4-tensor fine-structure clusters of 6-fold and 8-fold tunneling multiplets. Then extreme 12-fold and 24-fold multiplets are analyzed by RES plots of higher rank tensor Hamiltonians. Such extreme clustering is rare in fundamental bands but prevalent in hot bands, and analysis of its superfine structure requires more efficient labeling and a more powerful group theory. This is introduced using elementary examples involving two groups of order-6 (C6 and D3~C3v, then applied to families of Oh clusters in SF6 spectra and to extreme clusters.

  13. Unitary Evolution and Cosmological Fine-Tuning

    CERN Document Server

    Carroll, Sean M

    2010-01-01

    Inflationary cosmology attempts to provide a natural explanation for the flatness and homogeneity of the observable universe. In the context of reversible (unitary) evolution, this goal is difficult to satisfy, as Liouville's theorem implies that no dynamical process can evolve a large number of initial states into a small number of final states. We use the invariant measure on solutions to Einstein's equation to quantify the problems of cosmological fine-tuning. The most natural interpretation of the measure is the flatness problem does not exist; almost all Robertson-Walker cosmologies are spatially flat. The homogeneity of the early universe, however, does represent a substantial fine-tuning; the horizon problem is real. When perturbations are taken into account, inflation only occurs in a negligibly small fraction of cosmological histories, less than $10^{-6.6\\times 10^7}$. We argue that while inflation does not affect the number of initial conditions that evolve into a late universe like our own, it neve...

  14. Velocity measurement technique for high-speed targets based on digital fine spectral line tracking

    Institute of Scientific and Technical Information of China (English)

    Wen Shuliang; Yuan Qi

    2006-01-01

    Target velocity and acceleration are two of the most important features for identification of warheads and decoys in ballistic missile defense phased array radar systems. Velocity compensation is also the necessary step for one-dimensional range profile imaging. According to the high-velocity characteristics of ballistic objects and the low data rate of phased array radars with multiple target tracking, a fine spectral line digital velocity tracking frame is presented and a new method is developed to extract velocity error and resolve the velocity ambiguity in the measurement loop. Simulation results demonstrate the effectiveness of the proposed technique.

  15. Analysis of Grain Boundary Character in a Fine-Grained Nickel-Based Superalloy 718

    Science.gov (United States)

    Araujo, L. S.; dos Santos, D. S.; Godet, S.; Dille, J.; Pinto, A. L.; de Almeida, L. H.

    2014-11-01

    In the current work, sheets of superalloy 718 were processed via thermomechanical route by hot and cold rolling, followed by annealing below the δ phase solvus temperature and precipitation hardening to optimum strength. Grain boundary character distribution throughout the processing was mapped via EBSD and its evolution discussed. The results show that it is possible to process the alloy to a fine grain size obtaining concomitantly a considerably high proportion of special boundaries Σ3, Σ9, and Σ27. The precipitation of δ phase presented a strong grain refining role, without significantly impairing the twinning mechanism and, consequently, the Σ3, Σ9, and Σ27 boundary formations.

  16. Kinetics of electrodialytic extraction of Pb and soil cations from a slurry of contaminated soil fines

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Ottosen, Lisbeth M.; Ferreira, Célia;

    2006-01-01

    The objective of this work was to investigate the kinetics of Pb removal from soil-fines during electrodialytic remediation in suspension, and study the simultaneous dissolution of common soil cations (Al, Ca, Fe, Mg, Mn, Na and K). This was done to evaluate the possibilities within control......-removal was obtained. During the first phase dissolution of carbonates was the prevailing process, resulting in a corresponding loss of soil-mass. During this phase, the investigated ions accounted for the major current transfer, while, as remediation proceeded hydrogen-ions increasingly dominated the transfer. During...

  17. Mutagenic potential of fine wastes from dimension stone industry.

    Science.gov (United States)

    Aguiar, Luara Louzada; Tonon, Camila Bruschi; Nunes, Erika Takagi; Braga, Adriane Cristina Araújo; Neves, Mirna Aparecida; de Oliveira David, José Augusto

    2016-03-01

    The industrial treatment of dimension stones, such as marbles and granites, includes a stage of plate polishing, in which resins and abrasives are used, producing a fine grained waste with high moisture content. These wastes pass through decantation tanks in order to separate the solid and liquid phases. Until now, there is no knowledge about the mutagenic effects that this effluent can cause to organisms exposed to it. Thus, this study evaluated the mutagenic potential of dimension stone polishing wastes in onion root cells and fish erythrocytes. The onion seeds were germinated in Petri dishes with filter paper moistened in the liquid phase of the effluent. After germination, the onion roots were prepared for analysis of chromosomal aberrations in meristematic cells. The fishes were exposed during 72h to the solid phase of the effluent diluted in pure groundwater. Blood samples were used for counting of micronucleus and nuclear abnormalities. The onion seeds had similar germination and mitotic index in all treatments. However, it was observed in the seeds exposed to the polishing waste, numbers significantly higher of micronucleus, nuclear buds and other chromosomal aberrations when compared with the negative control. The fishes exposed to the waste showed numbers significantly higher of micronucleus when compared with the negative control. The fishes from all treatments showed significant increase in nuclear abnormalities when compared to the negative control. We concluded that the analysed wastes have mutagenic potential at the studied conditions; this effect can be related to the high content of phenolic compounds identified in the samples.

  18. Fining of glass melts: what we know about fining processes today

    NARCIS (Netherlands)

    Beerkens, R.G.C.

    2009-01-01

    The paper addresses the mechanisms of fining (removal of gases from melt) and the effect of batch composition, oxidation state of the melt and furnace atmosphere on bubble removal processes for commercial glass types, such as float glass and container glass compositions. The mechanisms of the

  19. Fining of glass melts: what we know about fining processes today

    NARCIS (Netherlands)

    Beerkens, R.G.C.

    2009-01-01

    The paper addresses the mechanisms of fining (removal of gases from melt) and the effect of batch composition, oxidation state of the melt and furnace atmosphere on bubble removal processes for commercial glass types, such as float glass and container glass compositions. The mechanisms of the differ

  20. Acclimation of fine root respiration to soil warming involves starch deposition in very fine and fine roots: a case study in Fagus sylvatica saplings.

    Science.gov (United States)

    Di Iorio, Antonino; Giacomuzzi, Valentino; Chiatante, Donato

    2016-03-01

    Root activities in terms of respiration and non-structural carbohydrates (NSC) storage and mobilization have been suggested as major physiological roles in fine root lifespan. As more frequent heat waves and drought periods within the next decades are expected, to what extent does thermal acclimation in fine roots represent a mechanism to cope with such upcoming climatic conditions? In this study, the possible changes in very fine (diameter Fagus sylvatica saplings subjected to a simulated long-lasting heat wave event and to co-occurring soil drying. For both very fine and fine roots, soil temperature (ST) resulted inversely correlated with specific root length, respiration rates and SSs concentration, but directly correlated with root mass, root tissue density and starch concentration. In particular, starch concentration increased under 28 °C for successively decreasing under 21 °C ST. These findings showed that thermal acclimation in very fine and fine roots due to 24 days exposure to high ST (∼ 28 °C), induced starch accumulation. Such 'carbon-savings strategy' should bear the maintenance costs associated to the recovery process in case of restored favorable environmental conditions, such as those occurring at the end of a heat wave event. Drought condition seems to affect the fine root vitality much more under moderate than high temperature condition, making the temporary exposure to high ST less threatening to root vitality than expected.

  1. Dispersal of fine sediment in nearshore coastal waters

    Science.gov (United States)

    Warrick, Jonathan A.

    2013-01-01

    Fine sediment (silt and clay) plays an important role in the physical, ecological, and environmental conditions of coastal systems, yet little is known about the dispersal and fate of fine sediment across coastal margin settings outside of river mouths. Here I provide simple physical scaling and detailed monitoring of a beach nourishment project near Imperial Beach, California, with a high portion of fines (40% silt and clay by weight). These results provide insights into the pathways and residence times of fine sediment transport across a wave-dominated coastal margin. Monitoring of the project used physical, optical, acoustic, and remote sensing techniques to track the fine portion of the nourishment sediment. The initial transport of fine sediment from the beach was influenced strongly by longshore currents of the surf zone that were established in response to the approach angles of the waves. The mean residence time of fine sediment in the surf zone—once it was suspended—was approximately 1 hour, and rapid decreases in surf zone fine sediment concentrations along the beach resulted from mixing and offshore transport in turbid rip heads. For example, during a day with oblique wave directions and surf zone longshore currents of approximately 25 cm/s, the offshore losses of fine sediment in rips resulted in a 95% reduction in alongshore surf zone fine sediment flux within 1 km of the nourishment site. However, because of the direct placement of nourishment sediment on the beach, fine suspended-sediment concentrations in the swash zone remained elevated for several days after nourishment, while fine sediment was winnowed from the beach. Once offshore of the surf zone, fine sediment settled downward in the water column and was observed to transport along and across the inner shelf. Vertically sheared currents influenced the directions and rates of fine sediment transport on the shelf. Sedimentation of fine sediment was greatest on the seafloor directly offshore

  2. Fine-Scale Structure of the Moho From Receiver Functions: Effects of a Deforming Crust

    Science.gov (United States)

    Zandt, G.; Gilbert, H.; Ozacar, A.; Owens, T. J.

    2004-12-01

    Andrija Mohorovicic, a Croatian seismologist, is credited with the first estimation in 1906 of crustal thickness using the critically refracted phase Pn. The crust-mantle boundary has become commonly known as the Moho and its depth, structure, formation, and evolution remains an important research topic in seismology, petrology, and tectonics. Other seismic phases sensitive to Moho depth and structure are the converted phases Ps and Sp, and the associated 2p1s and 1p2s reverberation phases that are isolated in receiver function waveforms. With sufficient station coverage, multiple receiver functions can be migrated and stacked into cross-sections of the crust. Crustal cross-sections from tectonically active regions reveal dramatic variations in amplitude and frequency content of Moho phases that we associate with fine-scale structure, and possibly anisotropy at the crust-mantle boundary. The Moho amplitude or "brightness" is a measure of the crust-mantle impedance contrast, thickness and structure within the crust-mantle boundary, and effects of scattering from 3D structure. Processes directly related to these Moho structures include crustal thickening, crustal extension, crustal flow, delamination or convective removal, and eclogitization. Therefore, the fine-scale seismological structure of the Moho is an important constraint in regional tectonic reconstructions. Examples of receiver function crustal images and their tectonic implications from the western US, South American Andes, and the Tibetan plateau will be reviewed.

  3. The influence of motor imagery on the learning of a fine hand motor skill.

    Science.gov (United States)

    Sobierajewicz, Jagna; Przekoracka-Krawczyk, Anna; Jaśkowski, Wojciech; Verwey, Willem B; van der Lubbe, Rob

    2017-01-01

    Motor imagery has been argued to affect the acquisition of motor skills. The present study examined the specificity of motor imagery on the learning of a fine hand motor skill by employing a modified discrete sequence production task: the Go/NoGo DSP task. After an informative cue, a response sequence had either to be executed, imagined, or withheld. To establish learning effects, the experiment was divided into a practice phase and a test phase. In the latter phase, we compared mean response times and accuracy during the execution of unfamiliar sequences, familiar imagined sequences, and familiar executed sequences. The electroencephalogram was measured in the practice phase to compare activity between motor imagery, motor execution, and a control condition in which responses should be withheld. Event-related potentials (ERPs) and event-related lateralizations (ERLs) showed strong similarities above cortical motor areas on trials requiring motor imagery and motor execution, while a major difference was found with trials on which the response sequence should be withheld. Behavioral results from the test phase showed that response times and accuracy improved after physical and mental practice relative to unfamiliar sequences (so-called sequence-specific learning effects), although the effect of motor learning by motor imagery was smaller than the effect of physical practice. These findings confirm that motor imagery also resembles motor execution in the case of a fine hand motor skill.

  4. Productions of ultra-fine powders and their use in high energetic compositions

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Yuri F.; Osmonoliev, Mirswan N.; Sedoi, Valentin S. [Institute of High Current Electronics RAS, 634055 Tomsk (Russian Federation); Arkhipov, Vladimir A.; Bondarchuk, Sergey S.; Vorozhtsov, Alexander B.; Korotkikh, Alexander G.; Kuznetsov, Valery T. [Tomsk State University, Lenin Ave., 36, Tomsk, 634034 (Russian Federation)

    2003-12-01

    Fine and ultra-fine powders are actively studied in pyrotechnics, explosives and propellants. The important questions are how to produce a powder with specified characteristics and how to use the powder produced. This paper presents an approach to the powder production by the exploding wire method. The influence of initial conditions on the properties of powders is discussed. The basic factors are as follows: the level and the uniformity of the energy, dissipated in the exploding wire metal; the density and the chemical activity of the surrounding gas; the initial radius of wire. Electron Microscopes (Transmission and Scanning) and the Surface BET Mehtod have been used for analyses. The production of ultra-fine powders based on such metals as Al, W, Zr, Cu, Fe, Ag, Co, In, Pt has been investigated. Different surrounding passive gases (nitrogen, argon, xenon, and helium) were used for producing powders of pure metals. Samples were studied by chemical methods. X-ray Diffraction and Electron Diffraction methods were used for the determination of the phase compositions. Characterization included also Differential Scanning Calorimetry and Thermogravimetry in air with a heating rate of 100 K/min. In summary, it was shown that the exploding wire method allows to produce ultra-fine powders of various metals. The results obtained can be applied directly to the production of powders with specified characteristics. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  5. Considering distortion product otoacoustic emission fine structure in measurements of the medial olivocochlear reflex.

    Science.gov (United States)

    Abdala, Carolina; Mishra, Srikanta K; Williams, Tracy L

    2009-03-01

    In humans, when the medial olivocochlear (MOC) pathway is activated by noise in the opposite ear, changes in distortion product otoacoustic emission (DPOAE) level, i.e., the MOC reflex, can be recorded in the test ear. Recent evidence suggests that DPOAE frequency influences the direction (suppression/enhancement) of the reflex. In this study, DPOAEs were recorded at fine frequency intervals from 500 to 2500 Hz, with and without contralateral acoustic stimulation (CAS) in a group of 15 adults. The MOC reflex was calculated only at DPOAE frequencies corresponding to peaks in the fine structure. Additionally, inverse fast-Fourier transform was conducted to evaluate MOC effects on individual DPOAE components. Results show the following: (1) When considering peaks only, the mean MOC reflex was -2.05 dB and 97% of observations reflected suppression, (2) CAS reduced distortion characteristic frequency component levels more than overlap component levels, and (3) CAS produced an upward shift in fine structure peak frequency. Results indicate that when the MOC reflex is recorded at DPOAE frequencies corresponding to fine structure maxima (i.e., when DPOAE components are constructive and in phase), suppression is reliably observed and level enhancement, which probably reflects component mixing in the ear canal rather than strength of the MOC reflex, is eliminated.

  6. The fluidity of boulder debris flows is affected by fine sediment in the pore water

    Science.gov (United States)

    Hotta, Norifumi; Kaneko, Takahiro; Iwata, Tomoyuki; Nishimoto, Haruo

    2013-04-01

    Basic equations for debris flows are frequently derived using the simple assumption of monogranular particles. However, actual debris flows include a great diversity of grain sizes, resulting in inherent features such as inverse grading, particle size segregation, and liquefaction of fine sediment. The liquefaction of fine sediment affects the fluidity of debris flows, although the behavior and influence of fine sediment in debris flows have not been examined sufficiently. This study used flume tests to detect the effect of fine sediment on the characteristics of laboratory debris flows consisting of particles with two diameters: one diameter was fixed at a large particle size, while the small diameters were varied with the experimental conditions. From the experiments, the greatest sediment concentration and flow depth were observed in the debris flows mixed with finer sediment, indicating increased flow resistance. Then, the experimental friction coefficient was compared with the theoretical friction coefficient derived by substituting the experimental values into the constitutive equations for debris flow. The theoretical friction coefficient was obtained from two models with different fine-sediment treatments: one assuming that all of the fine sediments were solid particles and the other that the particles consisted of a fluid phase involving pore water liquefaction. A discriminant index was introduced to clarify which contribution from the two models could better explain the experimental results. The comparison of the friction coefficients detected a fully liquefied state for the finest particle mixture with sediment. However, even with the same particle size, the debris flows could be regarded as a liquefied state, a solid state, or a partially liquefied transition state depending on the experimental conditions other than the sediment particle size. These results infer that the liquefaction of fine sediment in debris flows was induced not only by the

  7. Managing Fine Sediment in Regulated Rivers

    Science.gov (United States)

    Schmidt, J. C.

    2015-12-01

    A paradigm useful in managing dams and diversions is that the combined effects of changing flow regime and sediment supply perturb regulated rivers into sediment deficit or sediment surplus. In the U.S. Southwest, large dams constructed on interregional rivers typically create sediment deficit segments >100 km long. Further downstream, sediment surplus may occur if desert tributaries deliver sufficient amounts of fine sediment, such as parts of the Rio Grande, lower Green River, and Colorado River delta. Sediment surplus also occurs on most smaller regional rivers. The protocols for managing rivers perturbed into sediment deficit have been refined for the Colorado River downstream from Glen Canyon Dam but are nonetheless challenged by externally determined water-supply agreements that require annual water deliveries that sometimes occur when there has been little tributary resupply. Virtually all of the naturally supplied sand to the depleted, 100-km long Marble Canyon comes from the Paria River. The sand delivery rate since 2012 was sufficiently large to trigger short-duration controlled floods under the High Flow Experiment (HFE) Protocol. The sand mass balance of Marble Canyon since 2012 when the HFE Protocol was adopted was positive due to the combination of relatively large sand delivery from the Paria River and average total annual flows. Large total annual flows have the potential to export large amounts of sand and create a negative sand mass balance. Despite the challenge of managing a scarce and highly variable sand supply and occasional years of large reservoir releases, the long-term (2006-2015) sand mass balance for the upstream half of Marble Canyon is indeterminant and is positive for the downstream half of Marble Canyon. The apparent success of managing sand in Grand Canyon under deficit conditions suggests that fine sediment management protocols might be developed for other regulated rivers. Implementation would require establishment of networks of

  8. Quantitative phase imaging of arthropods

    Science.gov (United States)

    Sridharan, Shamira; Katz, Aron; Soto-Adames, Felipe; Popescu, Gabriel

    2015-01-01

    Abstract. Classification of arthropods is performed by characterization of fine features such as setae and cuticles. An unstained whole arthropod specimen mounted on a slide can be preserved for many decades, but is difficult to study since current methods require sample manipulation or tedious image processing. Spatial light interference microscopy (SLIM) is a quantitative phase imaging (QPI) technique that is an add-on module to a commercial phase contrast microscope. We use SLIM to image a whole organism springtail Ceratophysella denticulata mounted on a slide. This is the first time, to our knowledge, that an entire organism has been imaged using QPI. We also demonstrate the ability of SLIM to image fine structures in addition to providing quantitative data that cannot be obtained by traditional bright field microscopy. PMID:26334858

  9. Surface nanostructure formation mechanism of 45 steel induced by supersonic fine particles pombarding

    Institute of Scientific and Technical Information of China (English)

    Dema Ba; Shining Ma; Changqing Li; Fanjun Meng

    2008-01-01

    By means of supersonic fine particles bombarding (SFPB), a nanostruetured surface layer up to 15 μm was fabricated on a 45 steel plate with ferrite and pearlite phases. To reveal the grain refinement mechanism of SFPB-treated 45 steel, microstructure features of various sections in the treated surface were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Grain size increases with an increase of depth from the treated surface. Plastic deformation and grain refinement processes are accompanied by an increase in strain. Plastic deformation in the proeuteetoid ferrite phases has precedence over the pearlite phases. Grain refinement in the ferrite phases involves: the onset of dis-location lines (Dls), dislocation tangles (DTs) and dense dislocation walls (DDWs) in the original grains; the formation of fine la-mellar and roughly equiaxed cells separated by DDWs; by dislocation annihilation and rearrangement, the transformation of DDWS into subboundaries and boundaries and the formation of submicron grains or subgrains; the successive subdivision of grains to finer and finer scale, resulting in the formation of highly misoriented nano-grains. By contrast, eutectoid cementite phase accommodated swain in a sequence as follows: onset of elongated, bended and shear deformation under deformation stress of ferrites, short and thin cementites with a width of about 20-50 nm and discontinuous length were formed. Shorter and thinner cementites were developed into ultra-fine pieces under the action of high density dislocation and strains. At the top surface, some cementites were decomposed under severe plastic deformation. Experimental evidences and analysis indicate that surface nanocrystallization of 45 steel results from dislocation activities, high swains and high strain rate are necessary for the formation of nanocrystallites.

  10. Evaluation of hyperbaric filtration for fine coal dewatering. Fourth quarterly technical progress report: June 1, 1993--September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Parekh, B.K. [Univ. of Kentucky, Lexington, KY (United States); Hogg, R. [Pennsylvania State Univ., University Park, PA (United States); Fonseca, A. [CONSOL Inc., Library, PA (United States)

    1993-12-31

    The main objectives of the project are to investigate the fundamental aspects of particle-liquid interaction in fine coal dewatering, to conduct laboratory and pilot plant studies on the applicability of hyperbaric filter systems and to develop process conditions for dewatering of fine clean coal to less than 20 percent moisture. The program consist of three phases, Model Development, Laboratory Studies, and Field Testing. The Pennsylvania State University is leading efforts in Phase 1, the University of Kentucky in Phase 2, and Consol Inc. in Phase 3 of the program. All three organizations are involved in all the three phases of the program. The Pennsylvania State University is developing a theoretical model for hyperbaric filtration systems, whereas the University of Kentucky is conducting experimental studies to investigate fundamental aspects of particle-liquid interaction and application of high pressure filter in fine coal dewatering. The optimum filtration conditions identified in phase 1 and 2 will be tested in a Consol Inc. coal preparation plant using an Andritz Ruthner portable hyperbaric filtration unit.

  11. Fine tuning of cytosolic Ca 2+ oscillations

    Science.gov (United States)

    Dupont, Geneviève; Combettes, Laurent

    2016-01-01

    Ca 2+ oscillations, a widespread mode of cell signaling, were reported in non-excitable cells for the first time more than 25 years ago. Their fundamental mechanism, based on the periodic Ca 2+ exchange between the endoplasmic reticulum and the cytoplasm, has been well characterized. However, how the kinetics of cytosolic Ca 2+ changes are related to the extent of a physiological response remains poorly understood. Here, we review data suggesting that the downstream targets of Ca 2+ are controlled not only by the frequency of Ca 2+ oscillations but also by the detailed characteristics of the oscillations, such as their duration, shape, or baseline level. Involvement of non-endoplasmic reticulum Ca 2+ stores, mainly mitochondria and the extracellular medium, participates in this fine tuning of Ca 2+ oscillations. The main characteristics of the Ca 2+ exchange fluxes with these compartments are also reviewed. PMID:27630768

  12. The composition of fine fragrances is changing

    DEFF Research Database (Denmark)

    Rastogi, Suresh Chandra; Menné, Torkil; Johansen, Jeanne Duus

    2003-01-01

    . The products with the highest concentrations of allergens have been shown to be prestige perfumes intended for women. This investigation explores the possible development in formulation of prestige perfumes, with regard to their content of the chemically defined ingredients of the diagnostic patch test...... material, the fragrance mix (FM). 10 fine fragrances were subjected to chemical analysis: 5 of these had been launched years ago (1921-1990) and 5 were the latest launches by the same companies, introduced 2 months to 4 years before purchase. The analysis revealed that the 5 old perfumes contained a mean...... of 5 of the 7 target allergens of the FM, while the new perfumes contained a mean of 2.8 of the allergens. The mean concentrations of the target allergens were 2.6 times higher in the old perfumes than in the new perfumes, range 2.2-337. It is concluded that the old perfumes, which are still popular...

  13. Magnetic Tension of Sunspot Fine Structures

    CERN Document Server

    Venkatakrishnan, P

    2010-01-01

    The equilibrium structure of sunspots depends critically on its magnetic topology and is dominated by magnetic forces. Tension force is one component of the Lorentz force which balances the gradient of magnetic pressure in force-free configurations. We employ the tension term of the Lorentz force to clarify the structure of sunspot features like penumbral filaments, umbral light bridges and outer penumbral fine structures. We compute vertical component of tension term of Lorentz force over two active regions namely NOAA AR 10933 and NOAA AR 10930 observed on 05 January 2007 and 12 December 2006 respectively. The former is a simple while latter is a complex active region with highly sheared polarity inversion line (PIL). The vector magnetograms used are obtained from Hinode(SOT/SP). We find an inhomogeneous distribution of tension with both positive and negative signs in various features of the sunspots. The existence of positive tension at locations of lower field strength and higher inclination is compatible...

  14. [Fine needle aspiration cytology of mammography screening

    DEFF Research Database (Denmark)

    Engvad, B.; Laenkholm, A.V.; Schwartz, Thue W.

    2009-01-01

    INTRODUCTION: In the year 2000 a quality assurance programme for the preoperative breast diagnostics was introduced in Denmark. The programme was based on the "European guidelines for quality assurance in breast cancer screening and diagnosis" where - among other measures - five cytological...... diagnostic classes were introduced. The aim of this study was to evaluate the quality assurance programme in a screening population to determine whether fine needle aspiration cytology (FNAC) as first choice remains a useful tool in the preoperative diagnostics, or if needle core biopsy should be the first...... of 66% of the 783 FNACs had a malignant cytology diagnosis, which in 99% of the cases turned out to be the correct diagnosis. Four lesions were false positives all of which represented benign proliferative breast diseases. The surgical procedures in these cases were either excisional biopsy...

  15. The fine structure constant and numerical alchemy

    CERN Document Server

    Dattoli, Giuseppe

    2010-01-01

    We comment on past and more recent efforts to derive a formula yielding the fine structure constant in terms of integers and transcendent numbers. We analyse these "exoteric" attitudes and describe the myths regarding {\\alpha}, which seems to have very ancient roots, tracing back to Cabbala and to medieval alchemic conceptions. We discuss the obsession for this constant developed by Pauli and the cultural "environment" in which such an "obsession" grew. We also derive a simple formula for {\\alpha} in terms of two numbers {\\pi} and 137 only. The formula we propose reproduces the experimental values up to the last significant digit, it has not any physical motivation and is the result of an alchemic combination of numbers. We make a comparison with other existing formulae, discuss the relevant limits of validity by comparison with the experimental values and discuss a criterion to recover a physical meaning, if existing, from their mathematical properties.

  16. Fine needle aspiration biopsy of ophthalmic tumors☆

    Science.gov (United States)

    Singh, Arun D.; Biscotti, Charles V.

    2012-01-01

    A majority of intraocular tumors can be diagnosed based on clinical examination and ocular imaging studies, which obviate the need for diagnostic ophthalmic fine needle aspiration biopsy (FNAB). Overall, diagnostic accuracy of ophthalmic FNAB is high but limited cellularity can compromise the diagnostic potential of ophthalmic aspirate samples. The role of ophthalmic FNAB is limited in retinal tumors. Orbital FNAB should be considered in the evaluation of lacrimal gland tumors, orbital metastasis, and lymphoproliferative lesions. Negative cytologic diagnosis of malignancy should not be considered unequivocal proof that an intraocular malignancy does not exist. With improved understanding of genetic prognostic factors of uveal melanoma, ophthalmic FNAB is gaining popularity for prognostic purposes in combination with eye conserving treatment of the primary tumor. In special clinical indications, ancillary studies such as immunohistochemistry and FISH can be performed on ophthalmic FNAB samples. Assistance of an experienced cytopathologist cannot be overemphasized. PMID:23960981

  17. Some characteristics of fine beryllium particle combustion

    Science.gov (United States)

    Davydov, D. A.; Kholopova, O. V.; Kolbasov, B. N.

    2007-08-01

    Beryllium dust will be produced under plasma interaction with beryllium armor of the first wall in ITER. Exothermal reaction of this dust with water steam or air, which can leak into the reactor vacuum chamber in some accidents, gives concern in respect to reactor safety. Results of studies devoted to combustion of fine beryllium particles are reviewed in the paper. A chemically active medium and elevated temperature are prerequisite to the combustion of beryllium particles. Their ignition is hampered by oxide films, which form a diffusion barrier on the particle surface as a result of pre-flame oxidation. The temperature to initiate combustion of particles depends on flame temperature, particle size, composition of combustible mixture, heating rate and other factors. In mixtures enriched with combustible, the flame temperature necessary to ignite individual particles approaches the beryllium boiling temperature.

  18. Phase coexistence in ferroelectric solid solutions: Formation of monoclinic phase with enhanced piezoelectricity

    Directory of Open Access Journals (Sweden)

    Xiaoyan Lu

    2016-10-01

    Full Text Available Phase morphology and corresponding piezoelectricity in ferroelectric solid solutions were studied by using a phenomenological theory with the consideration of phase coexistence. Results have shown that phases with similar energy potentials can coexist, thus induce interfacial stresses which lead to the formation of adaptive monoclinic phases. A new tetragonal-like monoclinic to rhombohedral-like monoclinic phase transition was predicted in a shear stress state. Enhanced piezoelectricity can be achieved by manipulating the stress state close to a critical stress field. Phase coexistence is universal in ferroelectric solid solutions and may provide a way to optimize ultra-fine structures and proper stress states to achieve ultrahigh piezoelectricity.

  19. The influence of fine char particles burnout on bed agglomeration during the fluidized bed combustion of a biomass fuel

    Energy Technology Data Exchange (ETDEWEB)

    Scala, Fabrizio; Chirone, Riccardo [Istituto di Ricerche sulla Combustione, CNR, P.le V. Tecchio, 80-80125 Naples (Italy); Salatino, Piero [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, P.le V. Tecchio, 80-80125 Naples (Italy)

    2003-11-15

    The combustion of biomass char in a bubbling fluidized bed is hereby addressed, with specific reference to the influence that the combustion of fine char particles may exert on ash deposition and bed agglomeration phenomena. Experiments of steady fluidized bed combustion (FBC) of powdered biomass were carried out with the aim of mimicking the postcombustion of attrited char fines generated in the fluidized bed combustion of coarse char. Experimental results showed that the char elutriation rate is much smaller than expected on the basis of the average size of the biomass powder and of the carbon loading in the combustor. Samples of bed material collected after prolonged operation of the combustor were characterized by scanning electron microscopy (SEM)-EDX analysis and revealed the formation of relatively coarse sand-ash-carbon aggregates. The phenomenology is consistent with the establishment of a char phase attached to the bed material as a consequence of adhesion of char fines onto the sand particles. Combustion under sound-assisted fluidization conditions was also tested. As expected, enhancement of fines adhesion on bed material and further reduction of the elutriation rate were observed. Experimental results are interpreted in the light of a simple model which accounts for elutriation of free fines, adhesion of free fines onto bed material and detachment of attached fines by attrition of char-sand aggregates. Combustion of both free and attached char fines is considered. The parameters of the model are assessed on the basis of the measured carbon loadings and elutriation rates. Model computations are directed to estimate the effective size and the peak temperature of char-sand aggregates. The theoretical estimates of the effective aggregate size match fairly well those observed in the experiments.

  20. Subset Feature Learning for Fine-Grained Category Classification

    OpenAIRE

    Ge, Zongyuan; McCool, Christopher; Sanderson, Conrad; Corke, Peter

    2015-01-01

    Fine-grained categorisation has been a challenging problem due to small inter-class variation, large intra-class variation and low number of training images. We propose a learning system which first clusters visually similar classes and then learns deep convolutional neural network features specific to each subset. Experiments on the popular fine-grained Caltech-UCSD bird dataset show that the proposed method outperforms recent fine-grained categorisation methods under the most difficult sett...

  1. A case study on fine weather in Western Antarctic Peninsula

    Institute of Scientific and Technical Information of China (English)

    黄耀荣; 许淙; 尹涛; 张海影

    2001-01-01

    Great Wall Station, the local fine weather was studied. Pressure, temperature and humidity field, and aerological stratification were analyzed synoptically. Two kinds of fine weather with different physical characteristics were found; one was caused by the spreading of subtropical high with high temerature and high humidity, and another was connected with polar highwith low temperature and low humidity. The research provide a synoptic background for the local fine weather forecast.

  2. An Einstein-Cartan Fine Structure Constant Definition

    Directory of Open Access Journals (Sweden)

    Stone R. A. Jr.

    2010-01-01

    Full Text Available The fine structure constant definition given in Stone R.A. Jr. Progress in Physics, 2010, v.1, 11-13 is compared to an Einstein-Cartan fine structure constant definition. It is shown that the Einstein-Cartan definition produces the correct pure theory value, just not the measure value. To produce the measured value, the pure theory Einstein-Cartan fine structure constant requires only the new variables and spin coupling of the fine structure constant definition in [1].

  3. Implications of a Time-Varying Fine Structure Constant

    CERN Document Server

    Alfonso-Faus, A

    2002-01-01

    Much work has been done after the possibility of a fine structure constant being time-varying. It has been taken as an indication of a time-varying speed of light. Here we prove that this is not the case. We prove that the speed of light may or may not vary with time, independently of the fine structure constant being constant or not. Time variations of the speed of light, if present, have to be derived by some other means and not from the fine structure constant. No implications based on the possible variations of the fine structure constant can be imposed on the speed of light.

  4. Cell fine structure and function - Past and present

    Science.gov (United States)

    Fernandez-Moran, H.

    1970-01-01

    Electron microscopic studies of nerve membrane fine structure, discussing cell membrane multienzyme and macromolecular energy and information transduction, protein synthesis and nucleic acids interrelations

  5. Space qualification of an antireflection coating on the surface of a ruled grating prism: increasing the throughput of the single-object slitless spectroscopy mode of NIRISS onboard JWST

    Science.gov (United States)

    Albert, Loïc.; Doyon, René; Kuzmenko, Paul J.; Little, Steve L.; Enzor, Greg S.; Maszkiewicz, Michael

    2014-07-01

    Grating prisms (grism) designed for near-infrared spectroscopy typically make use of high-refractive index materials such as zinc selenide (ZnSe), at the expense of large Fresnel losses ( 18%). Part of the loss can be recovered by using anti-reflection (AR) coatings. The technique is however considered risky when applied on the ruled surface of a grating, especially for a space application at cryogenic temperature. Such a grism, made of ZnSe and machined at Lawrence Livermore National Laboratory (LLNL) is mounted in the Near-Infrared Slitless Spectrograph (NIRISS) onboard the James Webb Space Telescope (JWST). Its Single Object Slitless Spectrograph (SOSS) observing mode uses the ZnSe grism and a cross-dispersing prism to produce R=700 spectra in orders 1 and 2 to cover the 0.6 to 2.5 microns spectral domain. The ZnSe grism is blazed at 1.23 microns, has a density of 54 lines/mm and its triangular grooves have a depth of 700 nm, a base of 18 microns, with facets angled at 1.9 degrees. Here, an AR coating produced by Thin Film Lab (TFL) and deposited on the ruled surface of a ZnSe grism sample was space qualified. Atomic force microscopy (AFM) showed no groove profile change pre/post coating despite the large relative thickness of the AR coating to that of the groove depth ( 35%). Also, the wavefront error map remained almost unchanged at lambda/8 (peak-to-valley at 632 nm) and survived unscathed through a series of three cryogenic cycles to 20 K. Finally, the transmission gain across our operating spectral range was almost as high as that for a unruled surface covered with the same AR coating (10-15%).

  6. Hydrogen Reduction of Hematite Ore Fines to Magnetite Ore Fines at Low Temperatures

    Directory of Open Access Journals (Sweden)

    Wenguang Du

    2017-01-01

    Full Text Available Surplus coke oven gases (COGs and low grade hematite ores are abundant in Shanxi, China. Our group proposes a new process that could simultaneously enrich CH4 from COG and produce separated magnetite from low grade hematite. In this work, low-temperature hydrogen reduction of hematite ore fines was performed in a fixed-bed reactor with a stirring apparatus, and a laboratory Davis magnetic tube was used for the magnetic separation of the resulting magnetite ore fines. The properties of the raw hematite ore, reduced products, and magnetic concentrate were analyzed and characterized by a chemical analysis method, X-ray diffraction, optical microscopy, and scanning electron microscopy. The experimental results indicated that, at temperatures lower than 400°C, the rate of reduction of the hematite ore fines was controlled by the interfacial reaction on the core surface. However, at temperatures higher than 450°C, the reaction was controlled by product layer diffusion. With increasing reduction temperature, the average utilization of hydrogen initially increased and tended to a constant value thereafter. The conversion of Fe2O3 in the hematite ore played an important role in the total iron recovery and grade of the concentrate. The grade of the concentrate decreased, whereas the total iron recovery increased with the increasing Fe2O3 conversion.

  7. Hydrophobic Dewatering of Fine Coal. Topical report, March 1, 1995-March 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, R.; Sohn, S.; Luttrell, J.; Phillips, D.

    1997-12-31

    Many advanced fine coal cleaning technologies have been developed in recent years under the auspices of the U.S. Department of Energy. However, they are not as widely deployed in industry as originally anticipated. An important reason for this problem is that the cleaned coal product is difficult to dewater because of the large surface area associated with fine particles. Typically, mechanical dewatering, such as vacuum filtration and centrifugation, can reduce the moisture to 20-35% level, while thermal drying is costly. To address this important industrial problem, Virginia Tech has developed a novel dewatering process, in which water is displaced from the surface of fine particulate materials by liquid butane. Since the process is driven by the hydrophobic interaction between coal and liquid butane, it was referred to as hydrophobic dewatering (HD). A fine coal sample with 21.4 pm median size was subjected to a series of bench-scale HD tests. It was a mid-vol bituminous coal obtained from the Microcel flotation columns operating at the Middle Fork coal preparation plant, Virginia. All of the test results showed that the HD process can reduce the moisture to substantially less than 10%. The process is sensitive to the amount of liquid butane used in the process relative to the solids concentration in the feed stream. Neither the intensity nor the time of agitation is critical for the process. Also, the process does not require long time for phase separation. Under optimal operating conditions, the moisture of the fine coal can be reduced to 1% by weight of coal.

  8. Filler effect of fine particle sand on the compressive strength of mortar

    Science.gov (United States)

    Jaturapitakkul, Chai; Tangpagasit, Jatuphon; Songmue, Sawang; Kiattikomol, Kraiwood

    2011-04-01

    The river sand, which is a non-pozzolanic material, was ground into 3 different particle sizes. Portland cement type I was replaced by the ground river sands at 10wt%-40wt% of binder to cast mortar. Compressive strengths of mortar were investigated and the filler effect of different fine particles of sand on the compressive strength of mortar was evaluated. The results show that the compressive strength of mortar contributed from the filler effect of smaller particles is higher than that of the coarser ones. The difference in compressive strength of mortar tends to be greater as the difference in ground river sand fineness increases. The results also suggest that ASTM C618 specification is not practically suitable for specifying pozzolan in concrete since the strength activity index of mortar containing ground river sand (high crystalline phase) with 33.8wt% of particles retained on a 45-μm sieve can pass the strength requirement.

  9. Origin of fine structure of the giant dipole resonance in sd-shell nuclei

    CERN Document Server

    Fearick, R W; Matsubara, H; von Neumann-Cosel, P; Richter, A; Roth, R; Tamii, A

    2014-01-01

    A set of high resolution zero-degree inelastic proton scattering data on 24Mg, 28Si, 32S, and 40Ca provides new insight into the long-standing puzzle of the origin of fragmentation of the Giant Dipole Resonance (GDR) in sd-shell nuclei. Understanding is provided by state-of-the-art theoretical Random Phase Approximation (RPA) calculatios for deformed nuclei using for the first time a realistic nucleon-nucleon interaction derived from the Argonne V18 potential with the unitary correlation operator method and supplemented by a phenomenological three-nucleon contact interaction. A wavelet analysis allows to extract significant scales both in the data and calculations characterizing the fine structure of the GDR. The fair agreement supports that the fine structure arises from ground-state deformation driven by alpha clustering.

  10. Correlative multi-scale characterization of a fine grained Nd–Fe–B sintered magnet

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, T.T., E-mail: sasaki.taisuke@nims.go.jp [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Ohkubo, T.; Hono, K. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Une, Y.; Sagawa, M. [Intermetallics Co., Ltd., 1-36 Goryo Ohara, Nishikyo-Ku, Kyoto 615-8245 (Japan)

    2013-09-15

    The Nd-rich phases in pressless processed fine grained Nd–Fe–B sintered magnets have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and three dimensional atom probe tomography (3DAP). The combination of the backscattered electron (BSE) and in-lens secondary electron (IL-SE) images in SEM led to an unambiguous identification of four types of Nd-rich phases, NdO{sub x}, Ia3{sup ¯} type phase, which is isostructural to Nd{sub 2}O{sub 3}, dhcp-Nd and Nd{sub 1}Fe{sub 4}B{sub 4}. In addition, the 3DAP analysis of thin Nd-rich grain boundary layer indicate that the coercivity has a close correlation with the chemistry of the grain boundary phase. - Highlights: ► Multi-scale characterization of Nd–Fe–B sintered magnet by SEM/TEM/3DAP. ► Phase/chemistry identification of Nd-rich phases at grain boundary triple junctions. ► Identification of micron-scale distribution of Nd-rich phases by IL-SE and BSE SEM. ► Correlative SEM/3DAP analysis from a specific thin grain boundary phase.

  11. Quad-plane stereoscopic PIV for fine-scale structure measurements in turbulence

    Science.gov (United States)

    Naka, Y.; Tomita, K.; Shimura, M.; Fukushima, N.; Tanahashi, M.; Miyauchi, T.

    2016-05-01

    The fine-scale structure in turbulence is investigated by quad-plane stereoscopic particle image velocimetry (QPSPIV). The quad-plane consists of two each of different polarizations and wavelengths, and it provides three velocity components at four independent parallel planes. Measurements have been undertaken in the developed region of a turbulent round jet with a spatial resolution sufficient to capture the small-scale structures. The advantage of the QPSPIV is presented in terms of the spectral response in the evaluation of the out-of-plane velocity gradient. The full velocity gradient tensor is computed with a fourth-order finite difference scheme in the out-of-plane direction as well as the in-plane directions. The turbulence quantities, such as the vorticity components, the energy dissipation rate and the second and third invariants of the velocity gradient tensor, are computed according to their faithful definitions. The coherent fine-scale eddies are extracted from the present QPSPIV data. The probability density functions of the diameter and the maximum azimuthal velocity of the extracted eddies exhibit their peak at approximately 8η and 1.5u_k, respectively, where η and u_k are the Kolmogorov length and velocity. These values agree well with the data in the literature. The phase-averaged distributions of turbulence quantities around the coherent fine-scale eddy indicate an apparent elliptic feature around the axis. Furthermore, the state of the strain rate exerting the eddy is quantified from the phase-averaged distributions of eigenvalues of the strain rate tensor and the alignment of the corresponding eigenvectors against the axis. The present study gives a solid experimental support of the coherent fine-scale structures in turbulence, and the technique can be applied to various flow fields and to the higher Reynolds number condition.

  12. Spinodal decomposition in fine grained materials

    OpenAIRE

    Ramanarayan, H.; Abinandanan, TA

    2003-01-01

    We have used a phase field model to study spinodal decomposition in polycrystalline materials in which the grain size is of the same order of magnitude as the characteristic decomposition wavelength (lambda(SD))In the spirit of phase field models, each grain (i) in our model has an order parameter (eta(i)) associated with it; eta(i) has a value of unity inside the ith grain, decreasessmoothly through the grain boundary region to zero outside the grain. For a symmetric alloy of composition, c ...

  13. Measurements of Ultra-fine and Fine Aerosol Particles over Siberia: Large-scale Airborne Campaigns

    Science.gov (United States)

    Arshinov, Mikhail; Paris, Jean-Daniel; Stohl, Andreas; Belan, Boris; Ciais, Philippe; Nédélec, Philippe

    2010-05-01

    In this paper we discuss the results of in-situ measurements of ultra-fine and fine aerosol particles carried out in the troposphere from 500 to 7000 m in the framework of several International and Russian State Projects. Number concentrations of ultra-fine and fine aerosol particles measured during intensive airborne campaigns are presented. Measurements carried over a great part of Siberia were focused on particles with diameters from 3 to 21 nm to study new particle formation in the free/upper troposphere over middle and high latitudes of Asia, which is the most unexplored region of the Northern Hemisphere. Joint International airborne surveys were performed along the following routes: Novosibirsk-Salekhard-Khatanga-Chokurdakh-Pevek-Yakutsk-Mirny-Novosibirsk (YAK-AEROSIB/PLARCAT2008 Project) and Novosibirsk-Mirny-Yakutsk-Lensk-Bratsk-Novosibirsk (YAK-AEROSIB Project). The flights over Lake Baikal was conducted under Russian State contract. Concentrations of ultra-fine and fine particles were measured with automated diffusion battery (ADB, designed by ICKC SB RAS, Novosibirsk, Russia) modified for airborne applications. The airborne ADB coupled with CPC has an additional aspiration unit to compensate ambient pressure and changing flow rate. It enabled to classify nanoparticles in three size ranges: 3-6 nm, 6-21 nm, and 21-200 nm. To identify new particle formation events we used similar specific criteria as Young et al. (2007): (1) N3-6nm >10 cm-3, (2) R1=N3-6/N621 >1 and R2=N321/N21200 >0.5. So when one of the ratios R1 or R2 tends to decrease to the above limits the new particle formation is weakened. It is very important to notice that space scale where new particle formation was observed is rather large. All the events revealed in the FT occurred under clean air conditions (low CO mixing ratios). Measurements carried out in the atmospheric boundary layer over Baikal Lake did not reveal any event of new particle formation. Concentrations of ultra-fine

  14. Carbon burnout project-coal fineness effects

    Energy Technology Data Exchange (ETDEWEB)

    Mike Celechin [Powergen UK plc, Nottingham (United Kingdom)

    2004-02-01

    The aim of this DTI project is to establish good quality plant and rig data to demonstrate the effect of changing coal fineness on carbon burnout in a controlled manner, which can then be used to support computational fluid dynamics (CFD) and engineering models of the process. The modelling elements of the project were completed by Mitsui Babcock Energy Ltd., and validated using the data produced by the other partners. The full scale plant trials were successfully completed at Powergen's Kingsnorth Power Station and a full set of tests were also completed on Powergen's CTF. During these test both carbon-in-ash and NOx levels were seen to increase with increasing fuel particle size. Laboratory analysis of fly ash produced during the plant and rig trials revealed that only small differences in char morphology and reactivity could be detected in samples produced under significantly different operating conditions. Thermo Gravimetric Analysis was also undertaken on a range of PF size fractions collected form mills operating at different conditions. 3 refs., 13 figs., 1 tab.

  15. Plant practices in fine coal column flotation

    Energy Technology Data Exchange (ETDEWEB)

    Davis, V.L. Jr.; Bethell, P.J.; Stanley, F.L. [Pittston Coal Management Co., Lebanon, VA (United States); Luttrell, G.H. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States). Dept. of Mining and Minerals Engineering

    1995-10-01

    Five 3 m (10 ft) diameter Microcel{trademark} flotation columns were installed at Clinchfield Coal Company`s Middle Fork preparation facility in order to reduce product ash and increase recovery and plant capacity. The Middle Fork facility is utilized for the recovery of fine coal from a feed stream that consists primarily of 1.5 mm x 0 material. The columns replaced conventional flotation cells for the treatment of the minus 150 {micro}m fraction while spirals are used to upgrade the plus 150 {micro}m material in the plant feed. The addition of the column flotation circuit resulted in an increase in plant capacity in excess of 20 percent while reducing the flotation product ash content by approximately 7 percentage points. Flotation circuit combustible recovery wa increased by 17 percentage points. This paper discusses circuit design, commissioning, and sparging system design. Circuit instrumentation, level control, reagent system control, performance comparisons with conventional flotation, and general operating procedures are also discussed.

  16. The Fine Structure of the Parathyroid Gland

    Science.gov (United States)

    Trier, Jerry Steven

    1958-01-01

    The fine structure of the parathyroid of the macaque is described, and is correlated with classical parathyroid cytology as seen in the light microscope. The two parenchymal cell types, the chief cells and the oxyphil cells, have been recognized in electron micrographs. The chief cells contain within their cytoplasm mitochondria, endoplasmic reticulum, and Golgi bodies similar to those found in other endocrine tissues as well as frequent PAS-positive granules. The juxtanuclear body of the light microscopists is identified with stacks of parallel lamellar elements of the endoplasmic reticulum of the ergastoplasmic or granular type. Oxyphil cells are characterized by juxtanuclear bodies and by numerous mitochondria found throughout their cytoplasm. Puzzling lamellar whorls are described in the cytoplasm of some oxyphil cells. The endothelium of parathyroid capillaries is extremely thin in some areas and contains numerous fenestrations as well as an extensive system of vesicles. The possible significance of these structures is discussed. The connective tissue elements found in the perivascular spaces of macaque parathyroid are described. PMID:13502423

  17. Space Telescope Fine Guidance Sensor Bearing Anomaly

    Science.gov (United States)

    Loewenthal, S.; Esper, J.; Pan, J.; Decker, J.

    1996-01-01

    Early in 1993, a servo motor within one of three Fine Guidance Sensors (FGS) aboard the Hubble Space Telescope (HST) reached stall torque levels on several occasions. Little time was left to plan replacement during the first servicing mission, scheduled at the end of '93. Accelerated bearing life tests confirmed that a small angle rocking motion, known as Coarse Track (CT), accelerated bearing degradation. Saturation torque levels were reached after approximately 20 million test cycles, similar to the flight bearings. Reduction in CT operation, implemented in flight software, extended FGS life well beyond the first servicing mission. However in recent years, bearing torques have resumed upward trends and together with a second, recent bearing torque anomaly has necessitated a scheduled FGS replacement during the upcoming second servicing mission in '97. The results from two series of life tests to quantify FGS bearing remaining life, discussion of bearing on-orbit performance, and future plans to service the FGS servos are presented in this paper.

  18. The fine art of ‘sourcery’

    CERN Multimedia

    2009-01-01

    The commissioning of the new Linac4 source – first element of the new acceleration chain for the upgrade of the LHC (sLHC) – started at the beginning of July. After years of preparation but after only a few hours of fine-tuning of the numerous parameters involved, the source has delivered its first negative ions. The civil engineering work for the new Linac4 going on near Restaurant 2.While the LHC is preparing for restart, teams of experts involved in the sLHC project are also working on the new facilities that will allow the LHC to run at higher luminosity. The beginning of the new chain of accelerators is Linac4, whose excavation works started October last year. "The particle source that we are commissioning now will be installed at the beginning of the path", explains Maurizio Vretenar, Linac4 project leader. "It is a critical element of the chain as all protons that will circulate in the CERN accelerators will originate from it." The Linac 4 source is differ...

  19. Fine needle aspiration cytology in leprosy

    Directory of Open Access Journals (Sweden)

    Prasad PVS

    2008-01-01

    Full Text Available Background: Laboratory diagnosis of leprosy by slit skin smear and skin biopsy is simple but both techniques have their own limitations. Slit skin smear is negative in paucibacillary cases whereas skin biopsy is an invasive technique. Fine needle aspiration cytology (FNAC from skin lesions in leprosy with subsequent staining with May-Grunwald-Giemsa (MGG stain has been found useful. Aim: To evaluate the possible role of cytology in classifying leprosy patients. Methods: Seventy-five untreated cases of leprosy attending the outpatient department were evaluated. Smears were taken from their skin lesions and stained using the MGG technique. Skin biopsy was also done from the lesions, which was compared with cytology smears. Results: A correlation of clinical features with FNAC was noticed in 87.5% of TT, 92.1% of BT, 81% of BL, and 66% of LL cases. Correlation of clinical with histopathological diagnoses revealed 12.5% specificity in TT leprosy, 55.3% in BT, 52.4% in BL and 50% in LL, and 100% in neuritic and histoid leprosy cases. Both correlations were found to be statistically significant by paired t test analysis. Thus, it was possible to distinguish the tuberculoid types by the presence of epithelioid cells and the lepromatous types by the presence of lymphocytes and foamy macrophages. Conclusion: FNAC may be used to categorize the patients into paucibacillary and multibacillary types, but is not a very sensitive tool to classify the patients across the Ridley-Jopling spectrum.

  20. Fine Sediment Resuspension Dynamics in Moreton Bay

    Institute of Scientific and Technical Information of China (English)

    YOU Zai-jin; YIN Bao-shu

    2007-01-01

    A comprehensive field study has been undertaken to investigate sediment resuspension dynamics in the Moreton Bay, a large semi-enclosed bay situated in South East Queensland, Australia. An instrumented tripod, which housed three current meters, three OBS sensors and one underwater video camera, was used to collect the field data on tides, currents, waves and suspended sediment concentrations at four sites (Sites 1, 2, 4, and 5) in the bay. Site 1 was located at the main entrance, Site 2 at the central bay in deep water, and Sites 4 and 5 at two small bays in shallow water. The bed sediment was fine sand (d50=0.2 mm) at Site 1, and cohesive sediment at the other three sites. Based on the collected field data, it is found that the dominant driving forces for sediment resuspension are a combination of ocean swell and tidal currents at Site 1, tidal currents at Site 2, and wind-waves at Sites 4 and 5. The critical bed shear stress for cohesive sediment resuspension is determined as 0.079 Pa in unidirectional flow at Site 2, and 0.076 Pa in wave-induced oscillatory flow at Site 5.

  1. Percutaneous transhepatic cholangiography using fine needle

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Kyoo Byung; Kim, Yun Hwan; Lee, Nam Joon; Suh, Won Hyuck [College of Medicine, Korea University, Seoul (Korea, Republic of)

    1980-12-15

    In recent years, percutaneous transhepatic cholangiography (PTC) using fine needle has become widely employed as the procedure of choice for direct opacification of the biliary trees because of its high success rate, easy performance and relative low complication rate. Authors present the clinical and PTC findings of experienced cases during last four years, from May 1976 to June 1980, at the Department of Radiology, Korea University Hospital. We tried to study of PTC in 44 cases, 32 males and 12 females, and succeeded in visualization of bile ducts in 41 cases, but the other three cases were failed to visualize the bile ducts. Final confirmative diagnosis was achieved in 29 cases by operation, laparoscopy and other clinical methods. The PTC diagnosis was correct in 24 of 29 cases, and the others were incorrect. The 29 final diagnosis was including 13 cases of biliary stones, 6 cases of biliary cancer, 3 cases of pancreatic cancer, 3 cases of clonorchiasis, one case of CBD ascariasis and 3 cases of others. Incorrect PTC diagnosis was made in five cases. They were one case of nonvisualized intrahepatic stones, one case of hepatoma PTC diagnosed as cholangiocarcinoma, one case of pancreatic cancer diagnosed as cholangiocarcinoma, one case of clonorchiasis diagnosed as biliary stones and one case of normal CBD which was diagnosed as distal CBD cancer. And we experienced one case of bile peritonitis as complication, who was 35 year-old female patient with multiple CBD stones, and aspirated about 500ml of bile stained ascites during operation.

  2. Cosmological Constant, Fine Structure Constant and Beyond

    CERN Document Server

    Wei, Hao; Li, Hong-Yu; Xue, Dong-Ze

    2016-01-01

    In this work, we consider the cosmological constant model $\\Lambda\\propto\\alpha^{-6}$, which is well motivated from three independent approaches. As is well known, the evidence of varying fine structure constant $\\alpha$ was found in 1998. If $\\Lambda\\propto\\alpha^{-6}$ is right, it means that the cosmological constant $\\Lambda$ should be also varying. In this work, we try to develop a suitable framework to model this varying cosmological constant $\\Lambda\\propto\\alpha^{-6}$, in which we view it from an interacting vacuum energy perspective. We propose two types of models to describe the evolutions of $\\Lambda$ and $\\alpha$. Then, we consider the observational constraints on these models, by using the 293 $\\Delta\\alpha/\\alpha$ data from the absorption systems in the spectra of distant quasars, and the data of type Ia supernovae (SNIa), cosmic microwave background (CMB), baryon acoustic oscillation (BAO). We find that the model parameters can be tightly constrained to the narrow ranges of ${\\cal O}(10^{-5})$ t...

  3. Granular mechanics of normally consolidated fine soils

    Science.gov (United States)

    Yanqui, Calixtro

    2017-06-01

    In this paper, duality is demonstrated to be one of the inherent properties of granular packings, by mapping the stress-strain curve into the diagram that relates the pore ratio and the localization of the contact point. In this way, it is demonstrated that critical state is not related to the maximum void ratio, but to a unique value related to two different angles of packing, one limiting the domain of the dense state, and other limiting the domain of the loose state. As a consequence, packings can be dilative or contractive, as mutually exclusive states, except by the critical state point, where equations for both granular packings are equally valid. Further analysis shows that stresses, in a dilative packing, are transmitted by chains of contact forces, and, in a contractive packing, by shear forces. So that, stresses, for the first case, depend on the initial void ratio, and, for the second case, are independent. As it is known, normally consolidated and lightly overconsolidated fine soils are in loose state, and, hence, their strength is constant, because it does not depend on their initial void ratio; except at the critical state, for which, the consolidated-drained angle of friction is related to the plasticity index or the liquid limit. In this fashion, experimental results reported by several authors around the world are confronted with the theory, showing a good agreement.

  4. Fine needle aspiration cytology of dermal cylindroma

    Directory of Open Access Journals (Sweden)

    Parikshaa Gupta

    2014-01-01

    Full Text Available In this paper, we have described fine needle aspiration cytology (FNAC of a rare case of dermal cylindroma. A 40-year-old female presented with a lateral mid-cervical swelling fixed to the skin. FNAC smears showed multiple clusters of small, round to oval cells with hyperchromatic nuclei, inconspicuous nucleoli and scant cytoplasm. In addition, the background showed deposits of basement membrane type material. This was dark magenta colored pinkish globular material. The globules were occasionally surrounded by the basal type of cells. Occasional cells with elongated nuclei were also noted. Cytological diagnosis of skin adnexal tumor possibly cylindroma was offered. Subsequent histopathology of the swelling showed sheets and clusters of cells in a jigsaw puzzle-like fashion. Deposition of abundant basement membrane-like material was noted in between the tumor cells. A diagnosis of cylindorma was offered. FNAC along with the subcutaneous location of the tumor and absence of primary salivary gland tumor may help to diagnose such rare case.

  5. Fine coal measurement needs for improved control

    Energy Technology Data Exchange (ETDEWEB)

    Firth, B.; O' Brien, M. [CSIRO, Brisbane, Qld. (Australia). Division of Energy Technology

    2010-07-01

    The monitoring and management of fine coal circuits in coal preparation plants is limited in current practice. As part of the Australian Coal Association Research Program (ACARP) Intelligent Plant Project (C11069), the relationships between the main operational and control factors for the unit operations and the circuit and the performance indicators have been identified. The unit operations examined included desliming (hydrocyclones and sieve bends), small coal cleaning (spirals and hydraulic separators), flotation, and dewatering (vacuum filters, centrifuges, and thickeners). These relationships were then used to assist in the identification of the important parameters to be measured and the preferred level of accuracy required to be useful. An important issue was the interconnection between the various unit operations and the potential impact of an upstream problem on the subsequent performance of downstream units. Analysis with the relationships showed that the flow rate of respective feed slurries and the solids content were found to be significant variables. This article will discuss this analysis and provide some case studies.

  6. FINE AND COARSE PARTICLES: CONCENTRATION RELATIONSHIPS RELEVANT TO EPIDEMIOLOGICAL STUDIES

    Science.gov (United States)

    Fine particles and coarse particles are defined in terms of the modal structure of particle size distributions typically observed in the atmosphere. Differences among the various modes are discussed. The fractions of fine and coarse particles collected in specific size ranges, ...

  7. Shrinkage and swelling properties of flocculated mature fine tailings

    NARCIS (Netherlands)

    Yao, Y.; Van Tol, A.F.; Van Paassen, L.A.; Vardon, P.J.

    2014-01-01

    In the atmospheric fines drying technique, mature fine tailings (MFT) are treated with polymers and deposited in thin layers on a sloped surface for sub-aerial drying. During the whole drying period, the tailings deposits can experience rewetting during periods of rainy weather or as result of the

  8. Helping Preschoolers Prepare for Writing: Developing Fine Motor Skills

    Science.gov (United States)

    Huffman, J. Michelle; Fortenberry, Callie

    2011-01-01

    Early childhood is the most intensive period for the development of physical skills. Writing progress depends largely on the development of fine motor skills involving small muscle movements of the hand. Young children need to participate in a variety of developmentally appropriate activities intentionally designed to promote fine motor control.…

  9. Subjugated in the Creative Industries The Fine Arts in Singapore

    DEFF Research Database (Denmark)

    Ooi, Can-Seng

    2011-01-01

    to economic value. Fine arts practices will not be as lucrative or popular as their counterparts in the other creative businesses; they will remain poor cousins in the creative industries. Essentially, the fine arts are being subjugated in the creative industries and the Singaporean art world is being changed....

  10. RSW Mixed Element Cell-Centered Fine Mesh

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a RSW mixed-element unstructured fine mesh for cell-centered solvers. UG3 : Grid File Name = rsw_fine_mixedcc.b8.ugrid UG3 : Quad Surface Faces= 28968 UG3 :...

  11. A STUDY OF FINE PRECIPITATES IN ALLOYS BY POSITRON ANNIHILATION

    Institute of Scientific and Technical Information of China (English)

    王景成; 尤富强; 殷俊林; 高国华; 梁玲; 段勇

    2001-01-01

    Measurements were performed using the positron annihilation technique associated with physical metallurgical techniques for several engineering alloys containing fine precipitates. It is shown that positron annihilation is an effective method to detect fine precipitates, providing a sound basis for a further intense research of these.

  12. 7 CFR 400.454 - Disqualification and civil fines.

    Science.gov (United States)

    2010-01-01

    ... disqualification and civil fines will be imposed against: (i) Participants and other persons, except insurance... provision affects the approved insurance provider's responsibilities with respect to the service of existing... 7 Agriculture 6 2010-01-01 2010-01-01 false Disqualification and civil fines. 400.454 Section...

  13. Selective separation of fine particles by a new flotation approach

    NARCIS (Netherlands)

    Mulleneers, H.A.E.; Koopal, L.K.; Bruning, H.; Rulkens, W.H.

    2002-01-01

    Fine particles often create problems in flotation applications. In this article a new laboratory flotation system for the selective separation of small particles was designed and tested. The device contains an active counter current sedimentation that should prevent entrainment of the fine

  14. Deformation of fine-grained synthetic peridotite under wet conditions

    NARCIS (Netherlands)

    McDonnell, R.D.

    1997-01-01

    Fine-grained hydrated peridotite mylonites have been proposed to play an important role in controlling the strength of the continental lithosphere during rifting. For this reason, the deformation behaviour of wet fine-grained forsterite and forsterite-enstatite materials and the underlying deformati

  15. Search for Possible Variation of the Fine Structure Constant

    OpenAIRE

    2003-01-01

    Determination of the fine structure constant alpha and search for its possible variation are considered. We focus on a role of the fine structure constant in modern physics and discuss precision tests of quantum electrodynamics. Different methods of a search for possible variations of fundamental constants are compared and those related to optical measurements are considered in detail.

  16. Whole Brain Learning: The Fine Arts with Students at Risk

    Science.gov (United States)

    Respress, Trinetia; Lutfi, Ghazwan

    2006-01-01

    Schools are searching for more effective strategies that will enable all students to thrive and succeed. Evidence indicates that the fine arts can provide a unique avenue for reaching challenging students with principles of brain-based learning. This article describes HEARTS, an after-school fine arts program which taps and develops the talents of…

  17. Moon Phases

    Science.gov (United States)

    Riddle, Bob

    2010-01-01

    When teaching Moon phases, the focus seems to be on the sequence of Moon phases and, in some grade levels, how Moon phases occur. Either focus can sometimes be a challenge, especially without the use of models and observations of the Moon. In this month's column, the author describes some of the lessons that he uses to teach the phases of the Moon…

  18. Spinodal decomposition in fine grained materials

    Indian Academy of Sciences (India)

    H Ramanarayan; T A Abinandanan

    2003-01-01

    We have used a phase field model to study spinodal decomposition in polycrystalline materials in which the grain size is of the same order of magnitude as the characteristic decomposition wavelength ($\\lambda_{SD}$). In the spirit of phase field models, each grain () in our model has an order parameter ($\\eta_i$) associated with it; $\\eta_i$ has a value of unity inside the th grain, decreases smoothly through the grain boundary region to zero outside the grain. For a symmetric alloy of composition, = 0.5, our results show that microstructural evolution depends largely on the difference in the grain boundary energies, $\\gamma_{gb}$, of A-rich () and B-rich () phases. If $\\gamma^{\\alpha}_{gb}$ is lower, we find that the decomposition process is initiated with an layer being formed at the grain boundary. If the grain size is sufficiently small (about the same as $\\lambda_{SD}$), the interior of the grain is filled with the phase. If the grain size is large (say, about 10 $\\lambda_{SD}$ or greater), the early stage microstructure exhibits an A-rich grain boundary layer followed by a B-rich layer; the grain interior exhibits a spinodally decomposed microstructure, evolving slowly. Further, grain growth is suppressed completely during the decomposition process.

  19. Fines Classification Based on Sensitivity to Pore-Fluid Chemistry

    KAUST Repository

    Jang, Junbong

    2015-12-28

    The 75-μm particle size is used to discriminate between fine and coarse grains. Further analysis of fine grains is typically based on the plasticity chart. Whereas pore-fluid-chemistry-dependent soil response is a salient and distinguishing characteristic of fine grains, pore-fluid chemistry is not addressed in current classification systems. Liquid limits obtained with electrically contrasting pore fluids (deionized water, 2-M NaCl brine, and kerosene) are combined to define the soil "electrical sensitivity." Liquid limit and electrical sensitivity can be effectively used to classify fine grains according to their fluid-soil response into no-, low-, intermediate-, or high-plasticity fine grains of low, intermediate, or high electrical sensitivity. The proposed methodology benefits from the accumulated experience with liquid limit in the field and addresses the needs of a broader range of geotechnical engineering problems. © ASCE.

  20. Phase Closure Image Reconstruction for Future VLTI Instrumentation

    CERN Document Server

    Filho, Mercedes E; Garcia, Paulo; Duvert, Gilles; Duchene, Gaspard; Thiebaut, Eric; Young, John; Absil, Olivier; Berger, Jean-Phillipe; Beckert, Thomas; Hoenig, Sebastian; Schertl, Dieter; Weigelt, Gerd; Testi, Leonardo; Tatuli, Eric; Borkowski, Virginie; de Becker, Michael; Surdej, Jean; Aringer, Bernard; Hron, Joseph; Lebzelter, Thomas; Chiavassa, Andrea; Corradi, Romano; Harries, Tim

    2008-01-01

    Classically, optical and near-infrared interferometry have relied on closure phase techniques to produce images. Such techniques allow us to achieve modest dynamic ranges. In order to test the feasibility of next generation optical interferometers in the context of the VLTI-spectro-imager (VSI), we have embarked on a study of image reconstruction and analysis. Our main aim was to test the influence of the number of telescopes, observing nights and distribution of the visibility points on the quality of the reconstructed images. Our results show that observations using six Auxiliary Telescopes (ATs) during one complete night yield the best results in general and is critical in most science cases; the number of telescopes is the determining factor in the image reconstruction outcome. In terms of imaging capabilities, an optical, six telescope VLTI-type configuration and ~200 meter baseline will achieve 4 mas spatial resolution, which is comparable to ALMA and almost 50 times better than JWST will achieve at 2.2...

  1. Dust-cloud structures behind a shock wave moving over a deposited layer of fine particles

    Institute of Scientific and Technical Information of China (English)

    WANG Boyi; XIONG Yi; CHEN Qian; A.N. OSIPTSOV

    2005-01-01

    The present paper investigates dispersed-phase flow structures of a dust cloud induced by a normal shock wave moving at a constant speed over a flat surface deposited with fine particles. In the shock-fitted coordinates, the general equations of dusty-gas boundary layer flows are formulated within the framework of a multi-fluid model and parametric numerical studies of the carrier- and dispersedphase flow fields are performed. The problem associated with crossing particle trajectories and the formation of local particle accumulation regions are solved by using the full Lagrangian method for the dispersed phase. The basic features of the near-wall two-phase flow under consideration including the role of Saffman force in the particle entrainment and the development of discontinuities or singularities in the particle density profiles are discussed. The effects associated with account of the non-uniformity of particle size and the finiteness of the particle Knudsen numbers are studied in detail.

  2. MOTORIC STIMULATION RELATED TO FINE MOTORIC DEVELOPMENT ON CHILD

    Directory of Open Access Journals (Sweden)

    Mira Triharini

    2017-07-01

    Full Text Available Introduction: Motor developmental stimulation is an activity undertaken to stimulate the children basic skills and so they can grow and develop optimally. Children who obtain a direct stimulus will grow faster than who get less stimulus. Mother’s behavior of stimulation is very important for children, it is considering as the basic needs of children and it must be fulfilled. Providing good stimulation could optimize fine motor development in children. The purpose of this study was to analyze mother’s behavior about motor stimulation with fine motor development in toddler age 4-5 years old. Method: Design have been  used in this study was cross sectional. Population were mothers and their toddler in Group A of Dharma Wanita Persatuan Driyorejo Gresik Preschool. Sample were 51 respondents recruited by using purposive sampling technique according to inclusion and exclusion criteria. The independent variable was mother’s behavior about motor stimulation whereas dependent variable was fine motor development in toddler. The data were collected using questionnaire and conducting observation on fine motor development based on Denver Development Screening Test (DDST. Data then analyzed using Spearman Rho (r test to find relation between mother’s behaviors about stimulation motor on their toddler fine motor development. Result: Results  of this study showed that there were correlations between mother’s knowledge and fine motor development in toddler (p=0.000, between mother’s attitude and fine motor development in toddler (p=0.000, and between mother’s actions and fine motor development in toddler (p=0.000. Analysis: In sort study found that there were relation between fine motor development and mother’s behavior. Discussion: Therefore mother’s behavior needed to be improved. Further research about stimulation motor and fine motor development aspects in toddler is required.

  3. Thermal phase curves of non-transiting terrestrial exoplanets 2. Characterizing airless planets

    CERN Document Server

    Maurin, A S; Hersant, F; Belu, A

    2011-01-01

    Context. The photometric signal we receive from a star hosting a planet is modulated by the variation of the planet signal with its orbital phase. Such phase variations are observed for transiting hot Jupiters with current instrumentation, and have also been measured for one transiting terrestrial planet (Kepler 10 b) and one non-transiting gas giant (Ups A b). Future telescopes (JWST and EChO) will have the capability to measure thermal phase curves of exoplanets including hot rocky planets in transiting and non-transiting configurations, and at different wavelengths. Short-period planets with a mass below 10 R_EARTH are indeed frequent and nearby targets (within 10 pc) are already known and more are to be found. Aims. To test the possibility to use multi-wavelengths infrared phase curves to constrain the radius, the albedo and the orbital inclination of a non-transiting planet with no atmosphere and on a 1:1 spin orbit resonance. Methods. We model the thermal emission of a synchronous rocky planet with no a...

  4. Fine velocity structures collisional dissipation in plasmas

    Science.gov (United States)

    Pezzi, Oreste; Valentini, Francesco; Veltri, Pierluigi

    2016-04-01

    In a weakly collisional plasma, such as the solar wind, collisions are usually considered far too weak to produce any significant effect on the plasma dynamics [1]. However, the estimation of collisionality is often based on the restrictive assumption that the particle velocity distribution function (VDF) shape is close to Maxwellian [2]. On the other hand, in situ spacecraft measurements in the solar wind [3], as well as kinetic numerical experiments [4], indicate that marked non-Maxwellian features develop in the three-dimensional VDFs, (temperature anisotropies, generation of particle beams, ring-like modulations etc.) as a result of the kinetic turbulent cascade of energy towards short spatial scales. Therefore, since collisional effects are proportional to the velocity gradients of the VDF, the collisionless hypothesis may fail locally in velocity space. Here, the existence of several characteristic times during the collisional relaxation of fine velocity structures is investigated by means of Eulerian numerical simulations of a spatially homogeneous force-free weakly collisional plasma. The effect of smoothing out velocity gradients on the evolution of global quantities, such as temperature and entropy, is discussed, suggesting that plasma collisionality can increase locally due to the velocity space deformation of the particle velocity distribution. In particular, by means of Eulerian simulations of collisional relaxation of a spatially homogeneous force-free plasma, in which collisions among particles of the same species are modeled through the complete Landau operator, we show that the system entropy growth occurs over several time scales, inversely proportional to the steepness of the velocity gradients in the VDF. We report clear evidences that fine velocity structures are dissipated by collisions in a time much shorter than global non-Maxwellian features, like, for example, temperature anisotropies. Moreover we indicate that, if small-scale structures

  5. EDITORIAL: Cluster issue on fine particle magnetism

    Science.gov (United States)

    Fiorani, D.

    2008-07-01

    This Cluster issue of Journal of Physics D: Applied Physics arises from the 6th International Conference on Fine Particle Magnetism (ICFPM) held in Rome during 9-12 October 2007 at the headquarters of the National Research Council (NCR). It contains a collection of papers based on both invited and contributed presentations at the meeting. The ICFPM Conferences have previously been held in Rome, Italy (1991), Bangor, UK (1996), Barcelona, Spain (1999), Pittsburgh, USA (2002) and London, UK (2004). The aim of this series of Conferences is to bring together the experts in the field of nanoparticle magnetism at a single forum to discuss recent developments in both theoretical and experimental aspects, and technological applications. The Conference programme included sessions on: new materials, novel synthesis and processing techniques, with special emphasis on self-organized magnetic arrays; theory and modelling; surface and interface properties; transport properties; spin dynamics; magnetization reversal mechanisms; magnetic recording media and permanent magnets; biomedical applications and advanced investigation techniques. I would like to thank the European Physical Society and the Innovative Magnetic and Superconducting Materials and Devices Project of the Materials and Devices Department and the Institute of Structure of Matter (ISM) of CNR for their support. Thanks are also due to the members of the Programme Committee, to the local Organizing Committee, chaired by Elisabetta Agostinelli and to all the Conference participants. I am also indebted to the many scientists who contributed to assuring the high-quality of this Cluster by donating their time to reviewing the manuscripts contained herein. Finally, I'd like to dedicate this issue to the memories of Jean Louis Dormann, a great expert in nanoparticle magnetism, who was one of the promoters and first organizers of this series of Conferences, and of Grazia Ianni, the Conference secretary, who died before her

  6. Catalyst fines behavior among FCC flue gas turbine blade rows -Effect of gaseous phase flow field distribution%烟气轮机叶片间隙中FCC催化剂细粉运动规律——气相流场分布的影响

    Institute of Scientific and Technical Information of China (English)

    杜玉朋; 赵辉; 杨朝合; 胡仁波; 张云

    2012-01-01

    针对近年来炼厂中出现的催化裂化烟气轮机内结垢严重的问题,首先采用数值模拟方法,探讨了烟机内部气相流场的分布.模拟结果表明:在动叶片的压力面上,气相速度分布较低、水气浓度分布较大以及温度分布较高的特点,使得随烟气进入烟机的催化剂颗粒极易在叶片压力面上堆积和熔融.此外,通过采用仪器分析的方法对新鲜剂、平衡剂和垢物进行了微观形貌(SEM)与矿物组成(XRD)等分析,结果表明:烟机叶片上的结垢主要是由催化剂颗粒堆积与颗粒中某些物质生成了低熔点共熔物共同作用的结果.所得结论可为进一步研究催化剂颗粒在烟机内的流动情况和揭示结垢机理等后续工作提供理论基础.%According to the problem of serious scale formation in the FCC flue gas turbines in many refineries, the distribution of gaseous phase flow field in flue gas turbines was studied by using a CFD-based numerical simulation method. The simulation shows that the distribution is characterized by low gas velocity, high humidity, and high temperature on the pressure-side of rotors, which makes the catalyst particles entrained by exhaust gases more readily accumulate and melt there. By means of instrumental analyses to fresh catalyst, equilibrium catalyst and scaling catalyst, including scanning electron microscope ( SEM) for micro-morphology analysis, and X-ray diffraction (XRD) for phase analysis, the catalyst scaling on the surface of blade is proved to be the concurrent consequence of particle accumulation and low-melting eutectic matter formation. The results provide a theoretical basis for further study on the catalyst particles behavior and the scaling mechanism in FCC flue gas turbines.

  7. Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques

    Institute of Scientific and Technical Information of China (English)

    Yumin Zhu; Hua Zhang; Liming Shao; Pinjing He

    2015-01-01

    Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW).In this study,we investigated fine particles of <2 mm,which are small fractions in MSW but constitute a significant component of the total heavy metal content,using bulk detection techniques.A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction.We also discussed the association,speciation and source apportionment of heavy metals.Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of <10 μm within the fine particles.Zn-Cu,Pb-Fe and Fe-Mn-Cr had significant correlations in terms of spatial distribution.The overlapped enrichment,spatial association,and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles.The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products.

  8. Mathematical modeling of atmospheric fine particle-associated primary organic compound concentrations

    Science.gov (United States)

    Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

    1996-08-01

    An atmospheric transport model has been used to explore the relationship between source emissions and ambient air quality for individual particle phase organic compounds present in primary aerosol source emissions. An inventory of fine particulate organic compound emissions was assembled for the Los Angeles area in the year 1982. Sources characterized included noncatalyst- and catalyst-equipped autos, diesel trucks, paved road dust, tire wear, brake lining dust, meat cooking operations, industrial oil-fired boilers, roofing tar pots, natural gas combustion in residential homes, cigarette smoke, fireplaces burning oak and pine wood, and plant leaf abrasion products. These primary fine particle source emissions were supplied to a computer-based model that simulates atmospheric transport, dispersion, and dry deposition based on the time series of hourly wind observations and mixing depths. Monthly average fine particle organic compound concentrations that would prevail if the primary organic aerosol were transported without chemical reaction were computed for more than 100 organic compounds within an 80 km × 80 km modeling area centered over Los Angeles. The monthly average compound concentrations predicted by the transport model were compared to atmospheric measurements made at monitoring sites within the study area during 1982. The predicted seasonal variation and absolute values of the concentrations of the more stable compounds are found to be in reasonable agreement with the ambient observations. While model predictions for the higher molecular weight polycyclic aromatic hydrocarbons (PAH) are in agreement with ambient observations, lower molecular weight PAH show much higher predicted than measured atmospheric concentrations in the particle phase, indicating atmospheric decay by chemical reactions or evaporation from the particle phase. The atmospheric concentrations of dicarboxylic acids and aromatic polycarboxylic acids greatly exceed the contributions that

  9. Fine-grained representation learning in convolutional autoencoders

    Science.gov (United States)

    Luo, Chang; Wang, Jie

    2016-03-01

    Convolutional autoencoders (CAEs) have been widely used as unsupervised feature extractors for high-resolution images. As a key component in CAEs, pooling is a biologically inspired operation to achieve scale and shift invariances, and the pooled representation directly affects the CAEs' performance. Fine-grained pooling, which uses small and dense pooling regions, encodes fine-grained visual cues and enhances local characteristics. However, it tends to be sensitive to spatial rearrangements. In most previous works, pooled features were obtained by empirically modulating parameters in CAEs. We see the CAE as a whole and propose a fine-grained representation learning law to extract better fine-grained features. This representation learning law suggests two directions for improvement. First, we probabilistically evaluate the discrimination-invariance tradeoff with fine-grained granularity in the pooled feature maps, and suggest the proper filter scale in the convolutional layer and appropriate whitening parameters in preprocessing step. Second, pooling approaches are combined with the sparsity degree in pooling regions, and we propose the preferable pooling approach. Experimental results on two independent benchmark datasets demonstrate that our representation learning law could guide CAEs to extract better fine-grained features and performs better in multiclass classification task. This paper also provides guidance for selecting appropriate parameters to obtain better fine-grained representation in other convolutional neural networks.

  10. Reliability of fine needle aspiration biopsy in large thyroid nodules.

    Science.gov (United States)

    Bozbıyık, Osman; Öztürk, Şafak; Ünver, Mutlu; Erol, Varlık; Bayol, Ümit; Aydın, Cengiz

    2017-01-01

    Fine needle aspiration biopsy provides one of the most important data that determines the treatment algorithm of thyroid nodules. Nevertheless, the reliability of fine needle aspiration biopsy is controversial in large nodules. The aim of this study was to evaluate the adequacy of fine needle aspiration biopsy in thyroid nodules that are four cm or greater. We retrospectively examined 219 patients files who underwent thyroidectomy for thyroid nodules that were greater than four centimeter between May 2007 and December 2012. Seventy-four patients with hyperthyroidism, and 18 patients without preoperative fine needle aspiration cytology were excluded from the study. Histopathologic results after thyroidectomy were compared with preoperative cytology results, and sensitivity and specificity rates were calculated. False-negativity, sensitivity and specificity rates of fine needle aspiration biopsy of thyroid nodules were found to be 9.7%, 55.5%, and 85%, respectively. Within any nodule of the 127 patients, 28 (22.0%) had thyroid cancer. However, when only nodules of at least 4 cm were evaluated, thyroid cancer was detected in 22 (17.3%) patients. In this study, fine needle aspiration biopsy of large thyroid nodules was found to have a high false-negativity rate. The limitations of fine-needle aspiration biopsy should be taken into consideration in treatment planning of thyroid nodules larger than four centimeters.

  11. Microstructures and Hardness of 8CrWMoV Steel with Multiple Types of Ultra Fine Carbides

    Institute of Scientific and Technical Information of China (English)

    DAI Yu-mei; ZHANG Zhan-ping; MA Yong-qing; QI Yu-hong; LIU Yan-xia; YU Tao

    2004-01-01

    The structure and hardness of 8CrWMoV steel with multiple types of ultra fine carbides are studied after annealing, quenching and tempering in this paper. The results show that multiple types of carbides M3C, M7C3, M23C6, M6C and MC were observed in the annealed steel. Nucleation and coalescence of new carbides, partial dissolution of original carbides in γ phase region during annealing at 800~840℃, result in ultra-fine carbides. Average size of the carbides is0.33~0.34μm in the steel annealed at 800~840℃. Because M3C and M23C6 dissolve easily in austenite, the high hardness HRC63~65 can be obtained by quenching at 840~860℃. Un-dissolved carbides M6C and MC (VC) can effectively prevent the coarsening of austenitic grain, and conduce to obtain very fine martensite. The retained austenite can be easy to decompose during tempering at low and middle temperature due to the precipitation of multiple types of carbides and the good tempering-resistance of the steel is obtained. The microstructure and property of the steel after heat treatment can be accurately explained by calculating based on phase equilibrium thermodynamic.Key Words: 8CrWMoV steel, ultra-fine carbide, heat treatment, microstructure, hardness

  12. Investigation of fine nanoparticles syngas catalyst (POM) considering their various morphology.

    Science.gov (United States)

    Fakhroueian, Z; Shafiekhani, A; Yousefi, M; Langroudi, N Afroukhteh; Karami, M; Varmazyar, H; Hemmati, M; Satari, S

    2010-02-01

    Ni/SiO2 fine nanoparticles were prepared by coprecipitation method using various nonionic surfactants as templates with Tylose as a binder dispersant. Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) have been used to study the templates influence on the morphology of the produced samples. Although the phase structure remained as a tetrahedron amorphous cristobalite-sin-SiO2 (101,100), rhombohedron and cubic NiO, but samples with different morphology (homogeneous nano spherical, nano rose flower and nano cubic shapes) have been achieved. These fine nanoparticles as syngas catalysts in Partial Oxidation of Methane to Hydrogen and Carbon Monoxide (POM) have been studied. Because of high Hydrogen production, it is a candidate to be a green fuel. A fixed-bed reactor at P = 1 atm, T = 800 degrees C, H2/CO = 1.8, GHSV (CH4) = 6000/hr and BET = 25, 63.5 and 87.1 m2/gr have been used as POM catalyst. From other hand these fine compounds could be converted to metallic nanotube (nanofiber) at above 850 degrees C and also bamboo shape tip mode carbon nanotube by thermal chemical vapor deposition at 800 degrees C. Transmission Electron Microscopy confirmed the metallic nanotube or single nano crystal growth. The Raman spectroscopy of all samples has been studied to confirm the different formation of Ni-Si. Choosing different templates for production of these nanoparticles could create width range of medical and industrial applications.

  13. Aging response of coarse- and fine-grained {beta} titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M. [G.V.Kurdyumov Institute for Metal Physics, National Academy of Sciences, 03142 Kyiv (Ukraine)]. E-mail: ivas@imp.kiev.ua; Markovsky, P.E. [G.V.Kurdyumov Institute for Metal Physics, National Academy of Sciences, 03142 Kyiv (Ukraine); Semiatin, S.L. [Air Force Research Laboratory, AFRL/ML, Wright-Patterson Air Force Base, OH 45433-7817 (United States); Ward, C.H. [Air Force Research Laboratory, AFRL/ML, Wright-Patterson Air Force Base, OH 45433-7817 (United States)

    2005-09-25

    The effect of heating rate to aging temperature and {beta} grain size on the aging behavior of three metastable {beta} titanium alloys, TIMETAL-LCB, VT22 and Ti-15-3-3-3 ('Ti-15-3'), was established using in situ resistivity measurements, X-ray diffraction, optical microscopy, SEM, TEM and STEM characterization. The results revealed the alloys could be divided into two classes based on their aging behavior. TIMETAL-LCB and VT-22 formed fine plate-like {alpha} at slow heating rates to the aging temperature. This behavior was determined to be due to the precipitation of isothermal {omega} at low temperatures, which serves as nucleation sites for {alpha}. The slow heating rate yielded the best balance of strength and ductility, particularly in alloys with a fine ({approx}10 {mu}m) {beta} grain size. At high heating rates, the formation of isothermal {omega} was avoided, leading to coarse, plate-like {alpha} microstructures with less desirable properties. Ti-15-3, on the other hand, exhibited {beta} phase separation during isothermal aging rather than isothermal {omega} formation. Much slower cooling rates were required to form fine {alpha} laths in Ti-15-3 compared to the other two alloys. The importance of specifying heating rate and aging temperature for the industrial heat treatment of {beta} titanium alloys was thus established.

  14. Vibration pore water pressure characteristics of saturated fine sand under partially drained condition

    Institute of Scientific and Technical Information of China (English)

    王炳辉; 陈国兴

    2008-01-01

    Vibration pore water pressure characteristics of saturated fine sand under partially drained condition were investigated through stress-controlled cyclic triaxial tests employed varied fine content of samples and loading frequency. In order to simulate the partially drained condition, one-way drainage for sample was implemented when cyclic loading was applied. The results show that the vibration pore water pressure’s response leads the axial stress and axial strain responses, and is lagged behind or simultaneous with axial strain-rate’s response for all samples in this research. In addition, the satisfactory linear relationship between vibration pore water pressure amplitude and axial strain-rate amplitude is also obtained. It means that the direct cause of vibration pore water pressure generation under partially drained conditions is not the axial stress or axial strain but the axial strain-rate. The lag-phase between pore water pressure and axial strain-rate increases with the increase of the fine content or the loading frequency.

  15. Fine-Structured Plasma Flows in Prominences

    Science.gov (United States)

    Panasenco, O.; Velli, M.; Landi, S.

    2008-12-01

    Plasmas in prominences (filaments against the disk) exhibit a very wide spectrum of different kind of motions. Here we analyze the plasma motions inside prominences observed by Hinode/SOT during 2006-2007 with focus on two spectacular examples from 25 April 2007 in Halpha line and 30 November 2006 in CaH line and then carry out some simulations of the possible dynamics. Most filaments are composed of fine threads of similar dimensions rooted in the chromosphere/photosphere. Recent observations of counter-streaming motions together with oscillations along the threads provide strong evidence that the threads are field aligned. To more correctly interpret the nature of observed downward flows of dense and cool plasma as well as the upward dark flows of less dense plasma, we take into account the geometry of the prominence structures and the viewing angle. The dark upflows exhibit turbulent patterns such as vortex formation and shedding that are consistent with the motions predicted by instabilities of the interchange type. Sometimes an appearance of dark motions is generated by dark voids opened in the prominence sheet after initiation of nearby downflow streams, implying mass drainage in the downflows. Based on 304 A observations, there is more filament mass in prominences than is visible in either the Halpha or CaH lines. The source of the downward moving plasma may be located either higher above the visible upper edge of the prominence or on the far end of the prominence spine. The bright downward motions of the more cool and dense plasma may be partly due to the counter-streaming motion along the magnetic fields lines and also to the presence of Rayleigh-Taylor type or ballooning/interchange instabilities in the upper regions of the prominence. Transverse motions of filament threads caused by magnetic instabilities constantly provide the conditions for reconnection in the low part of the corona and the chromosphere. We suggest that the combination of flows along

  16. Fine sediment dynamics in unsteady open-channel flow studied with acoustic and optical systems

    Science.gov (United States)

    Bagherimiyab, Fereshteh; Lemmin, Ulrich

    2012-09-01

    In order to simulate fine sediment dynamics over an armored bed in a tidal river, unsteady accelerating, then steady open-channel flow over a movable (but not moving) coarse gravel bed (D50=5.5 mm) was studied. A layer of fine sediment (D50=120 μm) was placed on the coarse gravel bed. The thickness of the fine sediment layer on the gravel bed was varied between 4 and 6 mm, but it was found that the thickness of the layer had no effect on the results. Quasi-instantaneous profiles of velocity and sediment concentration were taken simultaneously and co-located. An Acoustic Doppler Velocity Profiler (ADVP) was combined with Particle Tracking Velocimetry (PTV) for suspended sediment particle tracking. Measurements resolved turbulence scales. During the final phase of the accelerating flow range, fine sediment suspension from the bed started in packets and rapidly created a ripple pattern that remained nearly stationary. Thereafter, vortex shedding produced most of the sediment suspension into the water column in the form of events or packets, making suspension intermittent. Simultaneously, sediment particles rolled along the bed following the ripple structure, thus slowly advancing the ripple pattern in the direction of the flow without altering ripple geometry. Fine sediment particles and hydrogen bubbles were used individually or combined as flow tracers in the acoustic measurements. When used individually, hydrogen bubbles provided full depth flow and backscattering information, whereas sediment particles traced only the lower layers of the flow, indicating sediment suspension. When both tracers were combined, hydrogen bubbles could only be distinguished from sediment particles when results at two different acoustic carrier frequencies were compared. The intermittency was observed in the backscattering of the acoustic system. The event structure in fine sediment suspension is seen by the PTV method. PTV velocity vectors varied in speed and orientation, were

  17. Mineralogical characterization of quarry fines from Tracuateua city, state of Para, Brazil; Caracterizacao mineralogica dos finos de pedreira do municipio de Tracuateua-PA

    Energy Technology Data Exchange (ETDEWEB)

    Costa, J.H.B. da; Negrao, R.C.; Angelica, R.S., E-mail: jhcosta@ig.com.br [Instituto Federal de Educacao, Ciencia e Tecnologia do Para (IFPA), Belem, PA (Brazil). Departamento de Recursos Naturais. Coordenacao de Mineracao; Universidade Federal do Para (UFPA), Belem, PA (Brazil). Instituto de Geociencias

    2011-07-01

    The aim of this study was to characterize the mineralogy quarry fines samples for its reuse and thus contributing to mitigate the environmental impact caused by this waste. In order to achieve the results, samples were collected and prepared for assays and identification of the mineralogical phases present in the quarry fines from the samples. X-ray diffraction and optical microscopy techniques were used. The quarry of fines characterization was based on qualitatively identification the minerals present in the samples. It was detected the presence of quartz, muscovite and feldspar (albite and microclinite) by x-ray diffraction technique and microscopic and macroscopic observations. Moreover, the size distribution was determined, and the samples presented a medium to fine size (ranging from 9,5 mm to 0,075 mm) and the grains presented an irregular and angular shapes. (author)

  18. Block-to-Point Fine Registration in Terrestrial Laser Scanning

    Directory of Open Access Journals (Sweden)

    Jin Wang

    2013-12-01

    Full Text Available Fine registration of point clouds plays an important role in data analysis in Terrestrial Laser Scanning (TLS. This work proposes a block-to-point fine registration approach to correct the errors of point clouds from TLS and of geodetic networks observed using total stations. Based on a reference coordinate system, the block-to-point estimation is performed to obtain representative points. Then, fine registration with a six-parameter transformation is performed with the help of an Iterative Closest Point (ICP method. For comparisons, fine registration with a seven-parameter transformation is introduced by applying a Singular Value Decomposition (SVD algorithm. The proposed method not only corrects the registration errors between a geodetic network and the scans, but also considers the errors among the scans. The proposed method was tested on real TLS data of a dam surface, and the results showed that distance discrepancies of estimated representative points between scans were reduced by approximately 60%.

  19. Fine Particle Matter (PM2.5) Design Value

    Data.gov (United States)

    U.S. Environmental Protection Agency — Fine particulate matter or PM2.5 (total mass of particles below 2.5 micron is diameter) is known to cause adverse health effects in humans.See the following websites...

  20. A New Fine Damping Method for Solid ESG Rotor

    Institute of Scientific and Technical Information of China (English)

    LIU Chun-ning; TIAN Wei-feng; JIN Zhi-hua

    2006-01-01

    For the electrostatically suspended gyro(ESG) with solid rotor, because the equatorial photoelectric sensor won't sense the equatorial marking line and output the correct damping control information when the nutation angle is small, the active damping with equatorial marking line will bring considerable error. The passive damping method by applying strong DC magnetic field requires too much time. So an active damping method by longitude marking lines is proposed to fulfill the fine damping for solid ESG rotor. The shape of rotor marking lines and the principle of fine damping are introduced. The simulation results prove that this fine damping method can effectively solve the problem of damping error introduced by active damping with equatorial marking line. The estimating results for damping time indicate that the fine damping time is less than 10 percent of passive damping time.

  1. Study on conglutination model for fine moist material during screening

    Institute of Scientific and Technical Information of China (English)

    陈惜明; 邓凡政; 赵跃民; 朱红; 高庆宇

    2002-01-01

    All coal preparation in which fine coal is handled depends to some extent on the wettability of coal surface by water. The content of external water in fine moist material plays significant role on screening. This article probed into the causations why fine moist materials adhere to the screen deck on common vibrator in the process of screening. Although the wetting that results from interactions between the coal surface and water molecules that are determined by the composition of coal matrix (interrelated with coal rank) and heterogeneous constituents such as oxygen function groups, mineral impurities and pores have something to do with adhering, we found that the effect of wettability is not the key causation to agglomeration, in other words, water bridges among particles are the key causation to the fine moist materials adhesion. This paper also shows how the capillary adhesive forces forms and how to calculate and measure these forces.

  2. Advanced Portable Fine Water Mist Fire Extinguisher for Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fine water mist (FWM) is a promising replacement technology for fire suppression on the next generation of manned spacecraft. It offers advantages in performance,...

  3. Fine 5 segab vett, liiva ja videot / Tiit Tuumalu

    Index Scriptorium Estoniae

    Tuumalu, Tiit, 1971-

    2000-01-01

    Tantsutrupi Five 5 lavastustest (trupp tegutseb 1992. a., on väja kasvanud tantsuteatrist Nordic Star), ka 1992. a. Fine 5 juurde loodud stuudio-koolist, kus on võimalik õppida modern- ja nüüdistantsu

  4. Fine 5 segab vett, liiva ja videot / Tiit Tuumalu

    Index Scriptorium Estoniae

    Tuumalu, Tiit, 1971-

    2000-01-01

    Tantsutrupi Five 5 lavastustest (trupp tegutseb 1992. a., on väja kasvanud tantsuteatrist Nordic Star), ka 1992. a. Fine 5 juurde loodud stuudio-koolist, kus on võimalik õppida modern- ja nüüdistantsu

  5. Fine Structure of Solar Acoustic Oscillations Due to Rotation

    Science.gov (United States)

    Goode, P. R.; Dziembowski, W.

    1984-01-01

    The nature of the fine structure of high order, low degree five minute period solar oscillations following from various postulated forms of spherical rotation is predicted. The first and second order effects of rotation are included.

  6. Fine 5 tantsib Bachi järgi

    Index Scriptorium Estoniae

    2016-01-01

    Tantsuteater Fine 5 toob lavale lavastuse "HTK ehk hästi treenitud klaviir". Teos on loodud J.S. Bachi "Hästitempereeritud klaviiri" (HTK) esimese osa muusikale. Koreograafid Tiina Ollesk ja Renee Nõmmik

  7. Fluidization of fine powders cohesive versus dynamical aggregation

    CERN Document Server

    Valverde Millán, José Manuel

    2012-01-01

    This book illustrates the rich phenomenology exhibited by fine powders when fluidized by a gas flow, describing novel processes to assist fluidization by helping the gas flow to mobilize and break cohesive aggregates, which help to homogenize fluidization.

  8. performance of concrete with partial replacement of fine aggregates ...

    African Journals Online (AJOL)

    user

    Key Words: compressive strength, concrete, crushed waste glass, flexural strength, setting time, water absorption and workability. ... powder as partial replacement of fine aggregates up to ... water in cement paste and reactive silica in the WG.

  9. Fine 5 tantsib Bachi järgi

    Index Scriptorium Estoniae

    2016-01-01

    Tantsuteater Fine 5 toob lavale lavastuse "HTK ehk hästi treenitud klaviir". Teos on loodud J.S. Bachi "Hästitempereeritud klaviiri" (HTK) esimese osa muusikale. Koreograafid Tiina Ollesk ja Renee Nõmmik

  10. Process for preparing fine grain silicon carbide powder

    Science.gov (United States)

    Wei, G.C.

    Method of producing fine-grain silicon carbide powder comprises combining methyltrimethoxysilane with a solution of phenolic resin, acetone and water or sugar and water, gelling the resulting mixture, and then drying and heating the obtained gel.

  11. Spatial variability of fine particles in Parisian streets

    OpenAIRE

    Duché, Sarah; Beltrando, Gérard

    2012-01-01

    International audience; To study the spatial variability of airborne particles and to evaluate the personal and tourist exposure to fine particles in Paris, measurements of fine particles (PM2.5) concentrations have been made in Parisian streets in different mode of transport (bus, bike and walking), using a portable sensor. We use also meteorological parameters sensor (temperature,humidity and wind speed), a camera to view traffic and a GPS to compare with particles levels. PM2.5 levels are ...

  12. A FINE GRANULAR JOINT SOURCE CHANNEL CODING METHOD

    Institute of Scientific and Technical Information of China (English)

    Zhuo Li; Shen Lansun; Zhu Qing

    2003-01-01

    An improved FGS (Fine Granular Scalability) coding method is proposed in this letter, which is based on human visual characteristics. This method adjusts FGS coding frame rate according to the evaluation of video sequences so as to improve the coding efficiency and subject perceived quality of reconstructed images. Finally, a fine granular joint source channel coding is proposed based on the source coding method, which not only utilizes the network resources efficiently, but guarantees the reliable transmission of video information.

  13. Global Talent on Exhibit at Fine Arts Design Festival

    Institute of Scientific and Technical Information of China (English)

    Susan

    2003-01-01

    Rising young designers from around the worid revealed the creative trends in their field at the """"""""New Resource 2002 Design Festival,"""""""" held this fall by the Central Academy of Fine Arts {CAFA) in Beijing, With the theme of """"""""artistic design with new resources in the global economy and multicultural era"""""""", the event attracted over 50 academies and colleges of fine arts both home and abroad,

  14. Tree species richness affecting fine root biomass in European forests

    Science.gov (United States)

    Finér, Leena; Domisch, Timo; Vesterdal, Lars; Dawud, Seid M.; Raulund-Rasmussen, Karsten

    2016-04-01

    Fine roots are an important factor in the forest carbon cycle, contributing significantly to below-ground biomass and soil carbon storage. Therefore it is essential to understand the role of the forest structure, indicated by tree species diversity in controlling below-ground biomass and managing the carbon pools of forest soils. We studied how tree species richness would affect fine root biomass and its distribution in the soil profile and biomass above- and below-ground allocation patterns of different tree species. Our main hypothesis was that increasing tree species richness would lead to below-ground niche differentiation and more efficient soil exploitation by the roots, resulting in a higher fine root biomass in the soil. We sampled fine roots of trees and understorey vegetation in six European forest types in Finland, Poland, Germany, Romania, Italy and Spain, representing boreal, temperate and Mediterranean forests, established within the FunDivEUROPE project for studying the effects of tree species diversity on forest functioning. After determining fine root biomasses, we identified the percentages of different tree species in the fine root samples using the near infrared reflectance spectroscopy (NIRS) method. Opposite to our hypothesis we did not find any general positive relationship between tree species richness and fine root biomass. A weak positive response found in Italy and Spain seemed to be related to dry environmental conditions during Mediterranean summers. At the Polish site where we could sample deeper soil layers (down to 40 cm), we found more tree fine roots in the deeper layers under species-rich forests, as compared to the monocultures, indicating the ability of trees to explore more resources and to increase soil carbon stocks. Tree species richness did not affect biomass allocation patterns between above- and below-ground parts of the trees.

  15. Fluidized reduction of oxides on fine metal powders without sintering

    Science.gov (United States)

    Hayashi, T.

    1985-01-01

    In the process of reducing extremely fine metal particles (av. particle size or = 1000 angstroms) covered with an oxide layer, the metal particles are fluidized by a gas flow contg. H, heated, and reduced. The method uniformly and easily reduces surface oxide layers of the extremely fine metal particles without causing sintering. The metal particles are useful for magnetic recording materials, conductive paste, powder metallurgy materials, chem. reagents, and catalysts.

  16. Vilfredo Pareto e la fine del Sociale

    Directory of Open Access Journals (Sweden)

    Francesco Antonelli

    2017-08-01

    Full Text Available Il mondo contemporaneo è profondamente segnato dal declino delle pratiche e delle teorie sulla Società (Busino 1981: lì dove la modernità industriale è stata caratterizzata dal dominio “organicistico” dell’homo sociologicus, inteso come un attore definito dai suoi ruoli, integrato da strutture impersonali e parte di un sistema conflittuale prevalentemente economico (Dahrendorf 2010; Touraine 2008, la seconda modernità post-industriale e globale mette al centro il primato e l’autonomia dell’individuo. Questa fine della Società come fonte della moralità e dell’individuazione, al vertice della quale vi era lo Stato-nazione, ha dato vita a tre discorsi teorici, sospesi tra l’euristico e il normativo: il primo discorso promuove l’idea di una società degli individui che si autogoverna e si autoregola nel quadro del mercato globale, vista come la principale istituzione in grado di realizzare un equilibrio tra efficienza e soggettivazione; questo mercato non può comunque essere lasciato completamente a se stesso ma abbisogna di strumenti regolativi in grado di salvaguardare quel equilibrio: gli ordoliberalisti e, più in generale, i neoliberisti condividono questa posizione (Comisso 2017; Felice 2008; Foucault 2005; Röpke 2004. Il secondo discorso mette al centro l’idea di un soggetto personale, definito in maniera giusnaturalistica, che si oppone ai processi manipolativi e di dominio del sistema globale di potere. Questa idea di soggetto è anche la pietra angolare di ricostruzione possibile di un nuovo mondo caratterizzato dall’“universalismo delle differenze”: tra gli altri, Alain Touraine (2013; 1988, Martha Nussbaum (2013 e Nadia Urbinati (2011 condividono questo orientamento liberal. Il secondo discorso Infine, il terzo discorso ruota intorno ad un’idea di Sé desiderante e creativo che, attraverso idee come quelle di “moltitudine” (in luogo della categoria moderna di “popolo” e di “comune” (al

  17. A novel method for preparing ultra-fine alumina-borate oxide fibres via an electrospinning technique

    Science.gov (United States)

    Dai, Hongqin; Gong, Jian; Kim, Hakyong; Lee, Doukrae

    2002-10-01

    Alumina-borate/PVA composite fibres were prepared using sol-gel processing and an electrospinning technique. After calcination of the thin fibres, ultra-fine fibres of alumina-borate oxide with a diameter of about 550 nm could be prepared. The fibres were characterized by SEM, XRD and FT-IR. The results showed that the crystalline phase and morphology of alumina-borate fibres were largely influenced by the calcination temperature.

  18. SHAPE ANALYSIS OF FINE AGGREGATES USED FOR CONCRETE

    Directory of Open Access Journals (Sweden)

    Huan He

    2016-12-01

    Full Text Available Fine aggregate is one of the essential components in concrete and significantly influences the material properties. As parts of natures, physical characteristics of fine aggregate are highly relevant to its behaviors in concrete. The most of previous studies are mainly focused on the physical properties of coarse aggregate due to the equipment limitations. In this paper, two typical fine aggregates, i.e. river sand and crushed rock, are selected for shape characterization. The new developed digital image analysis systems are employed as the main approaches for the purpose. Some other technical methods, e.g. sieve test, laser diffraction method are also used for the comparable references. Shape characteristics of fine aggregates with different origins but in similar size ranges are revealed by this study. Compared with coarse aggregate, fine grains of different origins generally have similar shape differences. These differences are more significant in surface texture properties, which can be easily identified by an advanced shape parameter: bluntness. The new image analysis method is then approved to be efficient for the shape characterization of fine aggregate in concrete.

  19. Fine-grid calculations for stellar electron and positron capture rates on Fe isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Nabi, Jameel-Un, E-mail: jameel@giki.edu.pk [Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Faculty of Engineering Sciences (Pakistan); Tawfik, Abdel Nasser, E-mail: a.tawfik@eng.mti.edu.eg [MTI University, Egyptian Center for Theoretical Physics (ECTP) (Egypt)

    2013-03-15

    The acquisition of precise and reliable nuclear data is a prerequisite to success for stellar evolution and nucleosynthesis studies. Core-collapse simulators find it challenging to generate an explosion from the collapse of the core of massive stars. It is believed that a better understanding of the microphysics of core-collapse can lead to successful results. The weak interaction processes are able to trigger the collapse and control the lepton-to-baryon ratio (Y{sub e}) of the corematerial. It is suggested that the temporal variation of Y{sub e} within the core of a massive star has a pivotal role to play in the stellar evolution and a fine-tuning of this parameter at various stages of presupernova evolution is the key to generate an explosion. During the presupernova evolution of massive stars, isotopes of iron, mainly {sup 54-56}Fe, are considered to be key players in controlling Y{sub e} ratio via electron capture on these nuclides. Recently an improved microscopic calculation of weak-interaction-mediated rates for iron isotopes was introduced using the proton-neutron quasiparticle random-phase-approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic state-by-state calculation of stellar capture rates which greatly increases the reliability of calculated rates. The results were suggestive of some fine-tuning of the Y{sub e} ratio during various phases of stellar evolution. Here we present for the first time the fine-grid calculation of the electron and positron capture rates on {sup 54-56}Fe. The sensitivity of the pn-QRPA calculated capture rates to the deformation parameter is also studied in this work. Core-collapse simulators may find this calculation suitable for interpolation purposes and for necessary incorporation in the stellar evolution codes.

  20. Fine structures in Fe3Al alloy layer of a new hot dip aluminized steel

    Indian Academy of Sciences (India)

    Li Yajiang; Wang Juan; Zhang Yonglan; X Holly

    2002-12-01

    The fine structure in the Fe–Al alloy layer of a new hot dip aluminized steel (HDA) was examined by means of X-ray diffractometry (XRD), electron diffraction technique, etc. The test results indicated that the Fe–Al alloy layer of the new aluminized steel mainly composed of Fe3Al, FeAl and -Fe (Al) solid solution. There was no brittle phase containing higher aluminum content, such as FeAl3 (59.18% Al) and Fe2Al7 (62.93% Al). The tiny cracks and embrittlement, formerly caused by these brittle phases in the conventional aluminum-coated steel, were effectively eliminated. There was no microscopic defect (such as tiny cracks, pores or loose layer) in the coating. This is favourable to resist high temperature oxidation and corrosion of the aluminized steel.

  1. Adiponectin fine-tuning of liver regeneration dynamics revealed through cellular network modeling.

    Science.gov (United States)

    Correnti, Jason M; Cook, Daniel; Aksamitiene, Edita; Swarup, Aditi; Ogunnaike, Babatunde; Vadigepalli, Rajanikanth; Hoek, Jan B

    2014-11-10

    Following partial hepatectomy, the liver initiates a regenerative program involving hepatocyte priming and replication driven by coordinated cytokine and growth factor actions. We investigated the mechanisms underlying Adiponectin's (Adn) regulation of liver regeneration through modulation of these mediators. Adn-/- mice showed delayed onset of hepatocyte replication, but accelerated cell cycle progression relative to wild-type mice, suggesting Adn has multiple effects fine-tuning the kinetics of liver regeneration. We developed a computational model describing the molecular and physiological kinetics of liver regeneration in Adn-/- mice. We employed this computational model to evaluate the underlying regulatory mechanisms. Our analysis predicted that Adn is required for an efficient early cytokine response to partial hepatectomy, but is inhibitory to later growth factor actions. Consistent with this prediction, Adn knockout reduced hepatocyte responses to IL-6 during the priming phase, but enhanced growth factor levels through peak hepatocyte replication. By contrast, supraphysiological concentrations of Adn resulting from rosiglitazone treatment suppressed regeneration by reducing growth factor levels during S phase, consistent with computational predictions. Together, these results revealed that Adn fine-tunes the progression of liver regeneration through dynamically modulating molecular mediator networks and cellular interactions within the liver. This article is protected by copyright. All rights reserved.

  2. Adiponectin fine-tuning of liver regeneration dynamics revealed through cellular network modelling.

    Science.gov (United States)

    Correnti, Jason M; Cook, Daniel; Aksamitiene, Edita; Swarup, Aditi; Ogunnaike, Babatunde; Vadigepalli, Rajanikanth; Hoek, Jan B

    2015-01-15

    Following partial hepatectomy, the liver initiates a regenerative programme involving hepatocyte priming and replication driven by the coordinated actions of cytokine and growth factors. We investigated the mechanisms underlying adiponectin's (Adn) regulation of liver regeneration through modulation of these mediators. Adn(-/-) mice showed delayed onset of hepatocyte replication, but accelerated cell cycle progression relative to wild-type mice, suggesting Adn has multiple effects fine-tuning the kinetics of liver regeneration. We developed a computational model describing the molecular and physiological kinetics of liver regeneration in Adn(-/-) mice. We employed this computational model to evaluate the underlying regulatory mechanisms. Our analysis predicted that Adn is required for an efficient early cytokine response to partial hepatectomy, but is inhibitory to later growth factor actions. Consistent with this prediction, Adn knockout reduced hepatocyte responses to interleukin-6 during the priming phase, but enhanced growth factor levels through peak hepatocyte replication. By contrast, supraphysiological concentrations of Adn resulting from rosiglitazone treatment suppressed regeneration by reducing growth factor levels during S phase, consistent with computational predictions. Together, these results revealed that Adn fine-tunes the progression of liver regeneration through dynamically modulating molecular mediator networks and cellular interactions within the liver.

  3. Production of pyroxene ceramics from the fine fraction of incinerator bottom ash.

    Science.gov (United States)

    Bourtsalas, A; Vandeperre, L J; Grimes, S M; Themelis, N; Cheeseman, C R

    2015-11-01

    Incinerator bottom ash (IBA) is normally processed to extract metals and the coarse mineral fraction is used as secondary aggregate. This leaves significant quantities of fine material, typically less than 4mm, that is problematic as reuse options are limited. This work demonstrates that fine IBA can be mixed with glass and transformed by milling, calcining, pressing and sintering into high density ceramics. The addition of glass aids liquid phase sintering, milling increases sintering reactivity and calcining reduces volatile loss during firing. Calcining also changes the crystalline phases present from quartz (SiO2), calcite (CaCO3), gehlenite (Ca2Al2SiO7) and hematite (Fe2O3) to diopside (CaMgSi2O6), clinoenstatite (MgSiO3) and andradite (Ca3Fe2Si3O12). Calcined powders fired at 1080°C have high green density, low shrinkage (ceramics that have negligible water absorption. The transformation of the problematic fraction of IBA into a raw material suitable for the manufacture of ceramic tiles for use in urban paving and other applications is demonstrated. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Electro-Discharge Fine Truing of Metal-Bonded Fine-Grain Diamond Wheel Based on Real-Time Monitoring

    Institute of Scientific and Technical Information of China (English)

    JIN Weidong; REN Chengzu; HUA Jinhai; WANG Taiyong

    2005-01-01

    A data acquisition system based on LabVIEW is designed and implemented, and electro-discharge(ED) fine truing of metal-bonded fine-grain diamond wheel based on real-time monitoring is researched. Real-time monitoring not only makes efficient impulse specification of ED truing easily obtained, but also is good for timely identifying no-load, avoiding short circuit and arc discharge phenomena and then for obtaining normal machining state. ED fine truing of the fine-grain wheel includes two steps: rough truing for high efficiency and fine truing for high precision. Final ED truing precision and efficiency not only depend on electric process specification, but also is concerned with electrode shape, insulated performance of operating fluid and vertical feed quantity value and frequency. Experiments indicate that ED fine truing based on real-time monitoring can improve the truing precision and efficiency. Average machining efficiency of W10 wheel is about 0.95 μm/min; the final run-out by ED truing is less than 2 μm.

  5. NARSTO fine-particle and ozone assessments.

    Science.gov (United States)

    Hales, Jeremy M

    2003-01-01

    NARSTO, a tri-national North American consortium for applied tropospheric pollution research, conducts periodic assessments of air-pollution behavior to provide an information interface between the research community and individuals working in policy analysis and air-quality management. The first of these, entitled An Assessment of Tropospheric Ozone Pollution--A North American Perspective, appeared in late 2000 and has been circulated widely throughout the United States, Canada, Mexico, Europe, and South America. The second (currently) entitled NARSTO Assessment of the Atmospheric Science on Particulate Matter, is presently in its third-draft phase and is available for general review. A fourth draft, incorporating comments from the current review stage, will be submitted in January 2002 to a tri-national review committee composed of the Canadian Royal Society, the US National Academy of Sciences, and the Mexican Red de Desarrollo e Investigación de la Calidad del Aire en Grandes Ciudades. Finalization of the document will follow this review, which will conclude in July 2000. Publication is expected in December 2002. These two assessments contain substantial amounts of policy-relevant information, which is of interest to the research community as well as those working in policy analysis and air-quality management. This presentation provides a brief overview of features and findings of the two documents.

  6. Haggling over the fine-tuning price of LEP

    Science.gov (United States)

    Chankowski, Piotr H.; Ellis, John; Olechowski, Marek; Pokorski, Stefan

    1999-04-01

    We amplify previous discussions of the fine-tuning price to be paid by supersymmetric models in the light of LEP data. The whole range of tan β is discussed, including large values. In the minimal supergravity model with universal gaugino and scalar masses, a small fine-tuning price is possible only for intermediate values of tan β and for a small range of superpartner masses. Moreover, the fine-tuning price in this region is significantly higher if we require β-τ Yukawacoupling unification. We interpret the significant increase after LEP of the fine-tuning price in the minimal supergravity model as a message for theory and not for the experiment. For possible choices of low-energy parameters in the MSSM consistent with present experimental constraints and, optionally, with some other theoretical assumptions such as ifb-τ Yukawa-coupling unification, a measure of the amount of fine tuning becomes an interesting criterion for the naturalness of various theoretical models for mass terms in the MSSM Lagrangian. In particular, we emphasize that the fine-tuning price will depend on the actual solution to the μ problem. We illustrate the relevance of this fact by considering a simple ansatz of linear dependence of μ on M {1}/{2} or A0, showing that big price reductions are obtained in such cases. Significant price reductions are also obtained for large tan β if non-universal soft Higgs mass parameters are allowed. We also study input relations between MSSM parameters suggested in some interpretations of string theory: the price may depend significantly on these inputs, potentially providing guidance for building string models. However, in the available models the fine-tuning price may not be reduced significantly.

  7. Structure-phase states of the nickel surface layers after electroexplosive carburizing

    Institute of Scientific and Technical Information of China (English)

    Budovskikh; E.; A.; Bagautdinov; A.; Y.; Ivanov; Yu.; F.; Martusevich; E.; V.; Gromov; V.; E.

    2005-01-01

    The layer by layer study of the structure-phase states of the nickel surface layer carburizing with use the phenomena of the electrical explosion has conducted by the method TEM of the fine foils.……

  8. Shocks, star formation and the JWST

    Science.gov (United States)

    Gusdorf, A.

    2015-12-01

    The interstellar medium (ISM) is constantly evolving due to unremitting injection of energy in various forms. Energetic radiation transfers energy to the ISM: from the UV photons, emitted by the massive stars, to X- and γ-ray ones. Cosmic rays are another source of energy. Finally, mechanical energy is injected through shocks or turbulence. Shocks are ubiquitous in the interstellar medium of galaxies. They are associated to star formation (through jets and bipolar outflows), life (via stellar winds), and death (in AGB stellar winds or supernovae explosion). The dynamical processes leading to the formation of molecular clouds also generate shocks where flows of interstellar matter collide. Because of their ubiquity, the study of interstellar shocks is also a useful probe to the other mechanisms of energy injection in the ISM. This study must be conducted in order to understand the evolution of the interstellar medium as a whole, and to address various questions: what is the peculiar chemistry associated to shocks, and what is their contribution to the cycle of matter in galaxies ? What is the energetic impact of shocks on their surroundings on various scales, and hence what is the feedback of stars on the galaxies ? What are the scenarios of star formation, whether this star formation leads to the propagation of shocks, or whether it is triggered by shock propagation ? What is the role of shocks in the acceleration of cosmic rays ? Can they shed light on their composition and diffusion processes ? In order to progress on these questions, it is paramount to interpret the most precise observations with the most precise models of shocks. From the observational point of view, the James Webb Space Telescope represents a powerful tool to better address the above questions, as it will allow to observe numerous shock tracers in the infrared range at an unprecedented spatial and spectral resolution.

  9. Shocks, Star Formation, and the JWST

    CERN Document Server

    Gusdorf, Antoine

    2015-01-01

    The interstellar medium (ISM) is constantly evolving due to unremitting injection of energy in various forms. Energetic radiation transfers energy to the ISM: from the UV photons, emitted by the massive stars, to X- and $\\gamma$-ray ones. Cosmic rays are another source of energy. Finally, mechanical energy is injected through shocks or turbulence. Shocks are ubiquitous in the interstellar medium of galaxies. They are associated to star formation (through jets and bipolar outflows), life (via stellar winds), and death (in AGB stellar winds or supernovae explosion). The dynamical processes leading to the formation of molecular clouds also generate shocks where flows of interstellar matter collide. Because of their ubiquity, the study of interstellar shocks is also a useful probe to the other mechanisms of energy injection in the ISM. This study must be conducted in order to understand the evolution of the ISM as a whole, and to address various questions: what is the peculiar chemistry associated to shocks, and ...

  10. Permeability of wood pellets in the presence of fines.

    Science.gov (United States)

    Yazdanpanah, F; Sokhansanj, S; Lau, A K; Lim, C J; Bi, X; Melin, S; Afzal, M

    2010-07-01

    Broken pellets and fines are produced when pellets are handled. The resistance to air flow was measured for clean pellets and for pellets mixed with 1-20% broken pellets (fines). A pellet diameter was 6mm. The lengths ranged from 6 to 12 mm. Clean pellets were defined as particles that remained on a 4mm screen. A typical sieve analysis showed 30% of the mass of particles that passed through the 4mm screen was smaller than 1mm. The airflow rates used in the experiment ranged from 0.004 to 0.357 ms(-1). The corresponding pressure drop ranged from 1.9 to 271 Pam(-1) for clean pellets, from 4.8 to 1100 Pam(-1) for 10% fines content, and from 7.9 to 1800 Pam(-1) for 20% fines content. Coefficients of Hukill and Ives' equation were estimated for clean pellets and a multiplier was defined to calculate pressure drop for pellets mixed with fines.

  11. Permeability of wood pellets in the presence of fines

    Energy Technology Data Exchange (ETDEWEB)

    Yazdanpanah, F. [University of British Columbia, Vancouver; Lau, A.K. [University of British Columbia, Vancouver; Sokhansanj, Shahabaddine [ORNL; Lim, C. Jim [University of British Columbia, Vancouver; Melin, Staffan [University of British Columbia, Vancouver; Bi, X.T. [University of British Columbia, Vancouver; Afzal, M [University of New Brunswick

    2010-03-01

    Broken pellets and fines are produced during mechanical handlings of wood pellets. The resistance to air flow was measured for clean pellets and for pellets mixed with 1 to 20% broken pellets (fines). A pellet diameter was 6 mm. The lengths ranged from from 6 to 12 mm. Clean pellets were defined as particles that remained on a 4 mm screen. A typical sieve analysis showed 30% of the mass of particles passed through the 4 mm screen were smaller than 1 mm. The airflow rates used in the experiment ranged from 0.004 to 0.357 ms-1. The corresponding pressure drop ranged from 1.9 Pa m-1 to 271 Pa m-1 for clean pellets and from 4.8 to 1100 Pa m 1 for pellets mixed with 10% fines. The pressure drop increased for pellets mixed with increasing fines content. Coefficients of Hukill and Ives equation were estimated for clean pellets and a multiplier was defined to calculate pressure drop for pellets mixed with fines.

  12. Stabilization of Black Cotton Soil Using Micro-fine Slag

    Science.gov (United States)

    Shukla, Rajesh Prasad; Parihar, Niraj Singh

    2016-09-01

    This work presents the results of laboratory tests conducted on black cotton soil mixed with micro-fine slag. Different proportions of micro-fine slag, i.e., 3, 6, 9, 12 and 15 % were mixed with the black cotton soil to improve soil characteristics. The improvement in the characteristics of stabilized soil was assessed by evaluating the changes in the physical and strength parameters of the soil, namely, the Atterberg limits, free swell, the California Bearing Ratio (CBR), compaction parameters and Unconfined Compressive Strength (UCS). The mixing of micro-fine slag decreases the liquid limit, plasticity index and Optimum Moisture Contents (OMC) of the soil. Micro-fine slag significantly increases the plastic limit, UCS and CBR of the soil up to 6-7 % mixing, but mixing of more slag led to decrease in the UCS and CBR of the soil. The unsoaked CBR increased by a substantial amount unlike soaked CBR value. The swell potential of the soil is reduced from medium to very low. The optimum amount of micro-fine slag is found to be approximately 6-7 % by the weight of the soil.

  13. Fine-grained sediment dispersal along the California coast

    Science.gov (United States)

    Warrick, Jonathan A.; Storlazzi, Curt D.

    2013-01-01

    Fine-grained sediment (silt and clay) enters coastal waters from rivers, eroding coastal bluffs, resuspension of seabed sediment, and human activities such as dredging and beach nourishment. The amount of sediment in coastal waters is an important factor in ocean ecosystem health, but little information exists on both the natural and human-driven magnitudes of fine-grained sediment delivery to the coastal zone, its residence time there, and its transport out of the system—information upon which to base environmental assessments. To help fill these information gaps, the U.S. Geological Survey has partnered with Federal, State, and local agencies to monitor fine-grained sediment dispersal patterns and fate in the coastal regions of California. Results of these studies suggest that the waves and currents of many of the nearshore coastal settings of California are adequately energetic to transport fine-grained sediment quickly through coastal systems. These findings will help with the management and regulation of fine-grained sediment along the U.S. west coast.

  14. Landscape and fine scale habitat associations of the Loggerhead Shrike

    Science.gov (United States)

    Michaels, H.L.; Cully, J.E.

    1998-01-01

    This study was conducted to determine landscape and fine-scale vegetative variables associated with breeding Loggerhead Shrikes (Lanius ludovicianus) on Fort Riley Military Reservation, Kansas. Because Fort Riley is an Army training site, the influences of training disturbance to the vegetation, and range management practices on bird habitat patterns were also investigated. Breeding birds were surveyed in 1995 and 1996 using point counts. Survey plots were identified, a priori, at the landscape scale as either grassland, savannah, or woodland edge according to cover by woody vegetation. In 1996, fine-scale habitat at survey points and at bird use sites was measured and a principal components analysis used to characterize the fine-scale herbaceous vegetation structure. A military disturbance index was developed to quantify the severity of vehicle disturbance to the vegetation at survey and bird use sites. Shrikes were associated with savannah habitat at the landscape scale. Sites used by Loggerhead Shrikes were characterized at the fine-scale by tall, sparse, structurally heterogeneous herbaceous vegetation with high standing dead plant cover and low litter cover. At the fine-scale, tree and shrub density did not differ between sites used and not used by shrikes. Used sites did not differ from survey sites with respect to military training disturbance, hay harvest, or the number of years since a site was last burned. Our results in this study suggest that the shifting mosaic of vegetation on Fort Riley resulting from training and range management practices maintains adequate habitat for breeding shrikes.

  15. Modeling downstream fining in sand-bed rivers. II: Application

    Science.gov (United States)

    Wright, S.; Parker, G.

    2005-01-01

    In this paper the model presented in the companion paper, Wright and Parker (2005) is applied to a generic river reach typical of a large, sand-bed river flowing into the ocean in order to investigate the mechanisms controlling longitudinal profile development and downstream fining. Three mechanisms which drive downstream fining are studied: a delta prograding into standing water, sea-level rise, and tectonic subsidence. Various rates of sea-level rise (typical of the late Holocene) and tectonic subsidence are modeled in order to quantify their effects on the degree of profile concavity and downstream fining. Also, several other physical mechanisms which may affect fining are studied, including the relative importance of the suspended versus bed load, the effect of the loss of sediment overbank, and the influence of the delta bottom slope. Finally, sensitivity analysis is used to show that the grain-size distribution at the interface between the active layer and substrate has a significant effect on downstream fining. ?? 2005 International Association of Hydraulic Engineering and Research.

  16. Transport of fine sediment over a coarse, immobile riverbed

    Science.gov (United States)

    Grams, Paul E.; Wilcock, Peter R.

    2014-01-01

    Sediment transport in cobble-boulder rivers consists mostly of fine sediment moving over a coarse, immobile bed. Transport rate depends on several interrelated factors: boundary shear stress, the grain size and volume of fine sediment, and the configuration of fine sediment into interstitial deposits and bed forms. Existing models do not incorporate all of these factors. Approaches that partition stress face a daunting challenge because most of the boundary shear is exerted on immobile grains. We present an alternative approach that divides the bed into sand patches and interstitial deposits and is well constrained by two clear end-member cases: full sand cover and absence of sand. Entrainment from sand patches is a function of their aerial coverage. Entrainment from interstices among immobile grains is a function of sand elevation relative to the size of the immobile grains. The bed-sand coverage function is used to predict the ratio of the rate of entrainment from a partially covered bed to the rate of entrainment from a completely sand-covered bed, which is determined using a standard sand transport model. We implement the bed-sand coverage function in a morphodynamic routing model and test it against observations of sand bed elevation and suspended sand concentration for conditions of nonuniform fine sediment transport in a large flume with steady uniform flow over immobile hemispheres. The results suggest that this approach may provide a simple and robust method for predicting the transport and migration of fine sediment through rivers with coarse, immobile beds.

  17. Determination of fine particulate semi-volatile organic material at three eastern U.S. sampling sites.

    Science.gov (United States)

    Warner, K S; Eatough, D J; Stockburger, L

    2001-09-01

    Correct assessment of fine particulate carbonaceous material as a function of particle size is, in part, dependent on the determination of semi-volatile compounds, which can be lost from particles during sampling. This study gives results obtained for the collection of fine particulate carbonaceous material at three eastern U.S. sampling sites [Philadelphia, PA; Shenandoah National Park, VA; and Research Triangle Park (RTP), NC] using diffusion denuder technology. The diffusion denuder samplers allow for the determination of fine particulate organic material with no artifacts, due to the loss of semi-volatile organic particulate compounds, or collection of gas-phase organic compounds by the quartz filter during sampling. The results show that an average of 41, 43, and 59% of fine particulate organic material was lost as volatilized semi-volatile organic material during collection of particles on a filter at Philadelphia, RTP, and Shenandoah, respectively. The particle size distribution of carbonaceous material retained by a filter and lost from a filter during sampling was obtained for the samples collected at Philadelphia and Shenandoah. The carbonaceous material retained by the particles during sampling was found predominantly in particles smaller than 0.4 microm in aerodynamic diameter. In contrast, the semi-volatile organic material lost from the particles during sampling had a mass median diameter of approximately 0.5 microm.

  18. James Webb Space Telescope segment phasing using differential optical transfer functions

    CERN Document Server

    Codona, Johanan L

    2015-01-01

    Differential Optical Transfer Function (dOTF) is an image-based, non-iterative wavefront sensing method that uses two star images with a single small change in the pupil. We describe two possible methods for introducing the required pupil modification to the JWST, one using a small (phasing, which is new functionality. Since the actuator method requires only small displacements, it should provide a fast and safe phasing alternative that reduces mission risk and can be performed frequently for alignment monitoring and maintenance. Since a single actuator modification can be seen by all three cameras, it should be possible to calibrate the non-common-path aberrations between them. Large segment discontinuities can be measured using dOTFs in two filter bands. Using two im...

  19. Fine Root Productivity and Dynamics on a Forested Floodplain in South Carolina

    Science.gov (United States)

    Terrell T. Baker; William Conner; H. B. Graeme Lockaby; John A. Stanturf; Marianne K. Burke

    2001-01-01

    The highly dynamic, fine root component of forested wetland ecosystems fine root dynamics is a challenging endeavor in any system, but the difficulties are particularly evident in forested floodplains where frequent hydrologic fluctuations directly influence fine root dynamics. Fine root (53 mm) biomass, production, and turnover were estimated for three soils...

  20. Recycling of PET bottles as fine aggregate in concrete.

    Science.gov (United States)

    Frigione, Mariaenrica

    2010-06-01

    An attempt to substitute in concrete the 5% by weight of fine aggregate (natural sand) with an equal weight of PET aggregates manufactured from the waste un-washed PET bottles (WPET), is presented. The WPET particles possessed a granulometry similar to that of the substituted sand. Specimens with different cement content and water/cement ratio were manufactured. Rheological characterization on fresh concrete and mechanical tests at the ages of 28 and 365days were performed on the WPET/concretes as well as on reference concretes containing only natural fine aggregate in order to investigate the influence of the substitution of WPET to the fine aggregate in concrete. It was found that the WPET concretes display similar workability characteristics, compressive strength and splitting tensile strength slightly lower that the reference concrete and a moderately higher ductility.

  1. Photoelectric Measurement of the Fineness of Raw Silk

    Institute of Scientific and Technical Information of China (English)

    Wan-chun FEI

    2010-01-01

    In order to precisely measure the diameters for obtaining the fineness of rolling raw silk, the physical features of raw silk are analyzed. By means of Fresnel principle, diffractions caused by different transparent raw silk filaments are analyzed and simulated. Image data of raw silk filament measured by digital CMOS camera are analyzed and processed for obtaining the precise diameters of the filament with the relative error of less than 1%. On the assumption of appropriate elliptic cross-section of the filament, the cross-section area is calculated as the fineness of the filament. Measurement experiments are carried out. Finally, some suggestions are proposed for photoelectric measuring the fineness of raw silk.

  2. Development of High Sensitivity Nuclear Emulsion and Fine Grained Emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Kawahara, H.; Asada, T. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Naka, T. [Institute of Advanced Research, Nagoya University (Japan); Naganawa, N.; Kuwabara, K.; Nakamura, M. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)

    2014-08-15

    Nuclear emulsion is a particle detector having high spacial resolution and angular resolution. It became useful for large statistics experiment thanks to the development of automatic scanning system. In 2010, a facility for emulsion production was introduced and R and D of nuclear emulsion began at Nagoya university. In this paper, we present results of development of the high sensitivity emulsion and fine grained emulsion for dark matter search experiment. Improvement of sensitivity is achieved by raising density of silver halide crystals and doping well-adjusted amount of chemicals. Production of fine grained emulsion was difficult because of unexpected crystal condensation. By mixing polyvinyl alcohol (PVA) to gelatin as a binder, we succeeded in making a stable fine grained emulsion.

  3. Manufacture of Fine-Pored Ceramics by the Gelcasting Method

    Directory of Open Access Journals (Sweden)

    Bronisław Psiuk

    2017-01-01

    Full Text Available The fine-pored materials represent a wide range of applications and searches are being continued to develop methods of their manufacturing. In the article, based on measurements on fine-grained powders of Al2O3, TiO2, and SiO2, it has been demonstrated that gelcasting can be relatively simple method of obtaining of nanoporous materials with high values of both specific surface area and open porosity. The powders were dispersed in silica sol, and the gelling initiator was NH4Cl. The usefulness of experiment design theory for developing of fine-pored materials with high porosity and specific surface area was also shown.

  4. Fine Tuning Mission to reach those influenced by Darwinism

    Directory of Open Access Journals (Sweden)

    Roger Tucker

    2014-01-01

    Full Text Available The scientifically aware section of the South African population is increasing. Many are being exposed to the concept of Darwinian evolution. Exposure has generated a religious sub �people group� who have problems with Christianity because they have been influenced by the naturalistic element in Darwinian philosophy. Christian antagonism towards evolution has often prejudiced them unfavourably towards the gospel. Recent discoveries concerning the fine-tuning of the universe have now presented a window of opportunity for overcoming this. It may enable the church to �fine-tune� its missionary approach to present them with the gospel in a more acceptable manner. It is suggested that Paul�s Areopagus speech provides a model for such cross-cultural evangelism. A section is included at the end, describing some objections that have been raised against the cosmological fine-tuning apologetic.

  5. Effects of cellular fine structure on scattered light pattern.

    Science.gov (United States)

    Liu, Caigen; Capjack, Clarence E

    2006-06-01

    Biological cells are complex in both morphological and biochemical structure. The effects of cellular fine structure on light scattered from cells are studied by employing a three-dimensional code named AETHER which solves the full set of Maxwell equations by using the finite-difference time-domain method. It is shown that changes in cellular fine structure can cause significant changes in the scattered light pattern over particular scattering angles. These changes potentially provide the possibility for distinguishability of cellular intrastructures. The effects that features of different intrastructure have on scattered light are discussed from the viewpoint of diagnosing cellular fine structure. Finally, we discuss scattered light patterns for lymphocyte-like cells and basophil-like cells.

  6. 3D WHOLE-PROMINENCE FINE STRUCTURE MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Gunár, Stanislav; Mackay, Duncan H. [School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews, KY16 9SS (United Kingdom)

    2015-04-20

    We present the first 3D whole-prominence fine structure model. The model combines a 3D magnetic field configuration of an entire prominence obtained from nonlinear force-free field simulations, with a detailed description of the prominence plasma. The plasma is located in magnetic dips in hydrostatic equilibrium and is distributed along multiple fine structures within the 3D magnetic model. Through the use of a novel radiative transfer visualization technique for the Hα line such plasma-loaded magnetic field model produces synthetic images of the modeled prominence comparable with high-resolution observations. This allows us for the first time to use a single technique to consistently study, in both emission on the limb and absorption against the solar disk, the fine structures of prominences/filaments produced by a magnetic field model.

  7. Properties of Industrial Slag as Fine Aggregate in Concrete

    Directory of Open Access Journals (Sweden)

    A. Ananthi

    2015-04-01

    Full Text Available The main objective of this paper is to use the industrial waste such as bottom ash and Weld Slag (WS as the partial replacement for fine aggregates in concrete. This paper presents the chemical analysis and strength properties of industrial solid waste such as bottom ash, weld slag 1 (WS 1 and weld slag 2 (WS 2. Their chemical compositions were identified by X-ray powder diffraction (XRD analysis. The qualitative and quantitative elemental analysis of the bottom ash and weld slag was recognized by energy dispersive X-ray analysis and their morphology were studied by Scanning Electron Microscope (SEM. The compressive strength of concrete with 10% replacement of fine aggregate to the industrial waste shows higher strength than the normal concrete and hence this industrial waste can be used as fine aggregate in concrete.

  8. Helium 23P Fine Structure Measurement in a Discharge Cell

    Science.gov (United States)

    Zelevinsky, T.; Farkas, D.; Gabrielse, G.

    2005-12-01

    A precise measurement of helium 23P fine structure was carried out in a discharge cell using Doppler-free laser spectroscopy. It is the only known experiment to directly measure all three fine structure intervals at a 1 kHz level of accuracy. The 23P1 - 23P2 interval value agrees with other experiments but disagrees with theoretical predictions of two-electron QED. When this disagreement is resolved, the 23P0 - 23P1 interval measurement reported here will allow a determination of the fine structure constant to 14 parts in 109, surpassing the precision of the well known QED-independent quantum Hall effect and Josephson effect determinations. The discharge cell is shown to be advantageous in the study and correction of systematic frequency shifts related to light pressure, and the use of the cell ensures that the possible systematic errors are substantially different from those reported in other experiments.

  9. Theory of the fine structure of auroral kilometric radiation

    Science.gov (United States)

    Grabbe, C. L.

    1982-01-01

    Recent data from ISEE 1 show auroral kilometric radiation (AKR) with finely separated bands in frequency. The observation that the AKR fine structure frequency separation is about equal to the ion cyclotron frequency at the AKR source is strong evidence for the interaction of AKR and electrostatic ion cyclotron (EIC) waves in the source, as proposed by Grabbe et al. (1980) to explain the origin of AKR. It is pointed out that no other wave of frequency close to the band separation is known to exist in the auroral source region. The fine structure observed in the source region AKR is the first evidence for EIC waves in the lower source region (3000 - 5000 km attitude), as required in the theory of Grabbe et al.

  10. Research on rheological properties of micro-fine grouting cement

    Institute of Scientific and Technical Information of China (English)

    管学茂; 王雨利; 杨雷

    2003-01-01

    This article studies the influence of the fineness of cement, fly ash(FA), its composite admixture and the amount and way mixed with superplasticizer on the rheological properties of micro-fine cement(MC). By means of modern instruments and technologies (such as XRD, SEM, laser granulometer and superficial-potential apparatus etc.), the article studies the mineral compositions, the appearance character of grains, particle size distribution and superficial potential of FA and its composite materials. And through that, the reducing mechanism of FA is thoroughly analyzed. The study shows that FA and its composite admixture are excellent components which can effectively improve the rheological properties of micro-fine cement, and that the superplasticizer has a saturation point and the mixing way of it has a great influence on the rheological properties.

  11. Effects of slag fineness on durability of mortars

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In recent years, the usages of by-products and wastes in industry have become more important. The importance of the sustainable development is also of increasing. The utilizations of wastes, as mineral admixture or fine aggregate, reduce the consumption of the natural resources and improve the durability of concrete. In this study, the effect of the fineness on the high temperature and sulphate resistances of concrete mortar specimens, produced with ground granulated blast-furnace slag (GBFS)replacing cement, is investigated. The compressive and flexural strength test results for all series related to durability effects,exposing temperature and solutions, exposure times for these durability effects, slag content and fineness are discussed. Consequently, the optimum slag contents are determined for producing the sulphate and high temperature resistant mortars.

  12. Investigation on Fine Registration for SAR and Optical Image

    Directory of Open Access Journals (Sweden)

    You Hong-jian

    2014-02-01

    Full Text Available The registration of SAR and optical remote sensing image is the basise for fusing of multi-source image and comprehensive analysis. In this paper a new fine registration method for SAR and optical image is proposed. Firstly, three to four corresponding points are selected manually to realize a coarse registration that eliminates the differences in scale and rotation. Many characteristic points in the optical image are detected and the corresponding points in SAR image are extracted using normalized gradient correlations based on the different gradients by operators. An irregular triangle network is constructed using these corresponding points and each triangle region is finely registered. Finally SAR image and optical image are finely registered. Experiment and processed results demonstrate the feasibility of this method.

  13. Pressure flotation of nitrocellulose fines: Hydrodynamics and interfacial chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Grasso, D.; Hu, H.L. [Univ. of Connecticut, Storrs, CT (United States); LaFrance, P. [CH2M Hill, Denver, CO (United States); Kim, B.J. [Army Construction Engineering Lab., Champaign, IL (United States)

    1996-11-01

    The production of nitrocellulose (NC) creates large quantities of waste NC fines in wash water streams. Current processing techniques attempt to remove these fines by cross-flow microfiltration, pressure flotation, settling, centrifugation, and lime precipitation. Pressure flotation, or dissolved air flotation (DAF), is a solid/liquid separation process first developed in the ore processing industry. DAF has since found many applications in the environmental engineering field including: drinking water clarification, sludge thickening, and the clarification of wastewater from a variety of industrial and municipal processes. The work presented herein is part of a larger effort to explore techniques to recover and reuse nitrocellulose (NC) fines resulting from propellant manufacturing processes. Previous papers investigated NC particle stability and interfacial thermodynamics and developed a flotation trajectory model. This paper builds on that work and presents a sensitivity analysis of the flotation trajectory model. The sensitivity analysis explores both operational and parameter estimation uncertainty.

  14. Distortion product otoacoustic emission fine structure of symphony orchestra musicians

    DEFF Research Database (Denmark)

    Reuter, Karen; Hammershøi, Dorte

    2006-01-01

    Otoacoustic emissions (OAE) are sounds produced by the healthy inner ear. They can be measured as low-level signals in the ear canal and are used to monitor the functioning of outer hair cells. Many studies indicate that OAE might be a more sensitive measure to detect early noise-induced haring...... losses than pure-tone audiometry. The distortion product otoacoustic emission (DPOAE) fine structure is obtained when the ear is stiumulated by dual tone stimuli using a high frequency resolution. It is characterized by quasi-periodic variations across frequency, as it can be observed in the hearing...... threshold microstructure also. In this study the DPOAE fine structure is obtained for symphony orchestra musicians both for left and right ears and before and after the orchestra rehearsal. The DPOAE fine structure is analyzed in order to investigate, whether it contains more information about the state...

  15. Distortion product otoacoustic emission fine structure of symphony orchestra musicians

    DEFF Research Database (Denmark)

    Reuter, Karen; Hammershøi, Dorte

    Otoacoustic emissions (OAE) are sounds produced by the healthy inner ear. They can be measured as low-level signals in the ear canal and are used to monitor the functioning of outer hair cells.Several studies indicate that OAE might be a more sensitive measure to detect early noise-induced hearing...... losses than puretone audiometry. The distortion product otoacoustic emission (DPOAE) fine structure is obtained when the ear is stimulated by dual tone stimuli using a high frequency resolution. It is characterized by quasi-periodic variations across frequency, as it can be observed in the hearing...... threshold microstructure also. In this study DPOAE fine structures and hearing thresholds are obtained for symphony orchestra musicians both for left and right ears and before and after the orchestra rehearsal. DPOAE fine structures are analyzed with an automatic classification algorithm, which describes...

  16. An Improved Ductile Fracture Criterion for Fine-blanking Process

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhen; ZHUANG Xin-cun; XIE Xiao-long

    2008-01-01

    In order to accurately simnulate the fine-blanking process,a suitable ductile fracture is significant.So an evaluation strategy based on experimental and corresponding simulation results of tensile,compression,torsion and fine-blanking test is designed to evaluate five typical ductile fracture criteria,which are widely-used in metal forming process.The stress triaxiality and ductile damage of each test specimen are analyzed.The results show that none of these five criteria is sufficient for all tests.Furthermore,an improved fracture criterion based on Rice and Tracey model,taking the influence of both volume change and shape change of voids into account,is proposed.The characterization of this model for fine-blanking process is easily done by the tensile test and the prediction result shows good.

  17. Fine needle aspiration cytology of palpable supraclavicular lymph nodes

    Directory of Open Access Journals (Sweden)

    RC Adhikari

    2011-03-01

    Full Text Available Background: Fine needle aspiration cytology as a first line of investigation has assumed importance in diagnosing a variety of disease process. The aim of this study was to assess the diagnostic value of fine needle aspiration cytology in the evaluation of palpable supraclavicular lymph nodes. Materials and methods: This was a retrospective study of fine needle aspiration cytology of palpable supraclavicular lymph node done between January 1, 2007 and December 31, 2009. Fine needle aspiration cytology was performed on 149 patients (49 cases at Om Hospital & Research Centre and 100 cases at Tribhuvan University Teaching Hospital. Results: The right supraclavicular lymph node was enlarged in 55% cases, while the left supraclavicular lymph node alone was palpable in 40.3% cases and in 7 of 149 (4.7% cases, bilateral supraclavicular lymph nodes were palpable. Cytological diagnoses were categorized as reactive (8.7%, tuberculosis (41.6%, lymphoma (4.8% and metastasis (44.9%. Of a total of 74 cases of malignancy, 90.5% were non-lymphoid and 9.5% were lymphoid (5 Non-Hodgkin lymphoma and 2 Hodgkin lymphoma. Of the 67 cases of metastatic disease, three major types of malignancy found in supraclavicular lymph nodes were Squamous cell carcinoma (28 cases, adenocarcinoma (21 cases and others (small cell carcinoma, papillary thyroid carcinoma etc. Adenocarcinoma tended to metastasize to the left supraclavicular lymph node. Lung was the most common primary site (43.3%, followed by stomach, ovary, breast and larynx. However, in 28.4% cases, no primary site was found. Conclusion: The fine needle aspiration cytology can be used as a first line investigation in the evaluation of supraclavicular lymphadenopathy due to its low cost, simplicity and minimal invasiveness. Keywords: Supraclavicular lymph node; Fine needle aspiration cytology; Metastasis DOI: 10.3126/jpn.v1i1.4441 Journal of Pathology of Nepal (2011 Vol.1, 8-12  

  18. Phase transitions

    CERN Document Server

    Solé, Ricard V

    2011-01-01

    Phase transitions--changes between different states of organization in a complex system--have long helped to explain physics concepts, such as why water freezes into a solid or boils to become a gas. How might phase transitions shed light on important problems in biological and ecological complex systems? Exploring the origins and implications of sudden changes in nature and society, Phase Transitions examines different dynamical behaviors in a broad range of complex systems. Using a compelling set of examples, from gene networks and ant colonies to human language and the degradation o

  19. A hazard to health? Fine particles arouse worldwide interest

    Energy Technology Data Exchange (ETDEWEB)

    Karas, J.; Oesch, P.

    1998-07-01

    The most recent studies show that particles contained in the air that we breathe may have harmful effects on the health of asthmatics, children and old people in particular. Particle material found in ambient air is formed by emissions resulting from traffic, industry and other use of fuels. Nature`s own sources also have a significant effect on particle concentrations. The mechanisms by which fine particles may produce negative health effects are so far unknown. At present it is therefore impossible to assess the effects of emissions of fine particles resulting, for instance, from the use of fossil fuels

  20. Possibilities of raising the rate of fine coal flotation

    Energy Technology Data Exchange (ETDEWEB)

    Rubinstein, J.B.; Molchanov, A.E.; Chanturiya, V.A.; Guzenko, A.I. [Institute of Solid Fossil Fuels Preparation, Moscow (Russian Federation). Department of Flotation Equipment and Technological Processes Optimization

    1995-08-01

    The physical and chemical properties of coal particles change after fine grinding. A series of tests with narrow size fractions shows their floatability and the effect of fines content on the flotation response. Floatability distribution functions obtained using different reagents show that the flocculation-flotation method and flotation columns are highly efficient for upgrading coal. The methods include selective coagulation, selective flocculation, and oil agglomeration. For the flocculation-flotation process using latex (200-300 g/t), the concentrate ash was reduced by 2-3 percent, while tailings ash increased by 6-8 percent compared to conventional flotation. 11 refs., 7 figs., 2 tabs.

  1. Advanced froth flotation techniques for fine coal cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, R.H.; Luttrell, G.H. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States)

    1994-12-31

    Advanced column flotation cells offer many potential advantages for the treatment of fine coal. The most important of these is the ability to achieve high separation efficiencies using only a single stage of processing. Unfortunately, industrial flotation columns often suffer from poor recovery, low throughput and high maintenance requirements as compared to mechanically-agitated conventional cells. These problems can usually be attributed to poorly-designed air sparging systems. This article examines the problems of air sparging in greater detail and offers useful guidelines for designing bubble generators for industrial flotation columns. The application of these principles in the design of a successful advanced fine coal flotation circuit is also presented.

  2. Le strutture ecclesiastiche a Firenze a fine Settecento

    Directory of Open Access Journals (Sweden)

    Pietro Domenico Giovannoni

    2014-04-01

    Full Text Available Il saggio ricostruisce il quadro generale delle strutture ecclesiastiche della città di Firenze alla fine del XVIII secolo: la rete parrocchiale, il ruolo del Capitolo del Duomo e quello della Basilica di San Lorenzo, la presenza di monasteri e conventi di regolari maschili e femminili ed infine le numerose compagnie laicali. Dall’analisi emerge come ancora a fine Settecento le istituzioni ecclesiastiche cittadine fossero fortemente legate alla struttura sociale della città, agli interessi ed alle strategie economiche e di prestigio sociale messe in opera dai diversi ceti, dalla aristocazia ai ceti produttivi degli artigiani.

  3. On the MSSM Higgsino mass and fine tuning

    CERN Document Server

    Ross, Graham G.

    2016-08-10

    It is often argued that low fine tuning in the MSSM necessarily requires a rather light Higgsino. In this note we show that this need not be the case when a more complete set of soft SUSY breaking mass terms are included. In particular an Higgsino mass term, that correlates the $\\mu-$term contribution with the soft SUSY-breaking Higgsino masses, significantly reduces the fine tuning even for Higgsinos in the TeV mass range where its relic abundance means it can make up all the dark matter.

  4. On the MSSM Higgsino mass and fine tuning

    Science.gov (United States)

    Ross, Graham G.; Schmidt-Hoberg, Kai; Staub, Florian

    2016-08-01

    It is often argued that low fine tuning in the MSSM necessarily requires a rather light Higgsino. In this note we show that this need not be the case when a more complete set of soft SUSY breaking mass terms are included. In particular an Higgsino mass term, that correlates the μ-term contribution with the soft SUSY-breaking Higgsino masses, significantly reduces the fine tuning even for Higgsinos in the TeV mass range where its relic abundance means it can make up all the dark matter.

  5. Fine Dust in Augmented Reality: Creating Public Service Announcement

    Directory of Open Access Journals (Sweden)

    Eugene Kim

    2014-11-01

    Full Text Available This study discusses how to create a public service announcement about fine dust using AR technology. „Aurasma,‟ a free mobile app, was used to produce the PSA. The PSA mainly consists of four parts, a trigger image, a short animation, an interactive menu, and other media which provide additional information about fine dust as users press the menu buttons. This study also surveys the user‟s preference on a PSA using AR technology and its educational effectiveness.

  6. Study of Biomass Calcite as Fine Aggregate of Concrete

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; YU Yan

    2012-01-01

    The possibility of using crushed oyster shell to partly replace the fine aggregate of concrete was evaluated. The compressive strength and slump of concrete mixture with different amount of crushed oyster shell were tested and thus the appropriate dosage was determined. Additionally, the compatibility with super plasticizer and the stability in NazSO4 solution were also discussed to prove the feasibility of oyster shell as fine aggregate of concrete. The microstructure of concrete was observed with XRD and SEM techniques. This research provides the basis for the application of waste biomass calcite.

  7. Separation of Fine Particles by Using Colloidal Gas Aphrons

    Institute of Scientific and Technical Information of China (English)

    E.A.Mansur; 王运东; 戴猷元

    2004-01-01

    This paper presents a method of separation of fine particles, of the order of a few microns or less, from aqueous media by flotation using colloidal gas aphrons (CGAs) generated in aqueous solutions. More than 150 experiments were conducted to study the effects of surfactant type, surfactant concentration, CGAs flow rate, and particle concentration on the removal efficiency (fine particles of polystyrene were used as a target compound). The results indicate that CGAs, generated from cationic surfactant of hexdecyltrimethyl ammonicum bromide (HTAB) and anionic surfactant of sodium dodecylbenzne sulfonate (SDBS), are an effective method for the separation off ine particles of polystyrene from wastewater. The flotation yields are higher than 97%.

  8. A FINE GRANULAR JOINT SOURCE CHANNEL CODING METHOD

    Institute of Scientific and Technical Information of China (English)

    ZhuoLi; ShenLanusun

    2003-01-01

    An improved FGS (Fine Granular Scalability) coding method is proposed in this letter,which is based on human visual characteristics.This method adjusts FGS coding frame rate according to the evaluation of video sequences so as to improve the coding efficiency and subject perceived quality of reconstructed images.Finally,a fine granular joint source channel coding is proposed based on the source coding method,which not only utilizes the network resources efficiently,but guarantees the reliable transmission of video information.

  9. On the MSSM Higgsino mass and fine tuning

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Graham G. [Oxford Univ. (United Kingdom). Rudof Peierls Centre for Theoretical Physics; Schmidt-Hoberg, Kai [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Staub, Florian [CERN, Geneva (Switzerland). Theoretical Physics Dept.

    2016-03-15

    It is often argued that low fine tuning in the MSSM necessarily requires a rather light Higgsino. In this note we show that this need not be the case when a more complete set of soft SUSY breaking mass terms are included. In particular an Higgsino mass term, that correlates the μ-term contribution with the soft SUSY-breaking Higgsino masses, significantly reduces the fine tuning even for Higgsinos in the TeV mass range where its relic abundance means it can make up all the dark matter.

  10. On the MSSM Higgsino mass and fine tuning

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Graham G., E-mail: g.ross1@physics.ox.ac.uk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Schmidt-Hoberg, Kai, E-mail: kai.schmidt-hoberg@desy.de [Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607 Hamburg (Germany); Staub, Florian, E-mail: florian.staub@cern.ch [Theoretical Physics Department, CERN, Geneva (Switzerland)

    2016-08-10

    It is often argued that low fine tuning in the MSSM necessarily requires a rather light Higgsino. In this note we show that this need not be the case when a more complete set of soft SUSY breaking mass terms are included. In particular an Higgsino mass term, that correlates the μ-term contribution with the soft SUSY-breaking Higgsino masses, significantly reduces the fine tuning even for Higgsinos in the TeV mass range where its relic abundance means it can make up all the dark matter.

  11. Fine structure of fields in 2D photonic crystal waveguides

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Volkov, V. S.; Bozhevolnyi, S. I.

    2006-01-01

    We resolve fine structure of fields in a single-row missing photonic crystal waveguide by finite-difference time-domain modelling and SNOM measurements. Both linear dispersion and slow-light regimes in proximity of the cutoff are addressed in the analysis.......We resolve fine structure of fields in a single-row missing photonic crystal waveguide by finite-difference time-domain modelling and SNOM measurements. Both linear dispersion and slow-light regimes in proximity of the cutoff are addressed in the analysis....

  12. cuBLASTP: Fine-Grained Parallelization of Protein Sequence Search on CPU+GPU.

    Science.gov (United States)

    Zhang, Jing; Wang, Hao; Feng, Wu-Chun

    2017-01-01

    BLAST, short for Basic Local Alignment Search Tool, is a ubiquitous tool used in the life sciences for pairwise sequence search. However, with the advent of next-generation sequencing (NGS), whether at the outset or downstream from NGS, the exponential growth of sequence databases is outstripping our ability to analyze the data. While recent studies have utilized the graphics processing unit (GPU) to speedup the BLAST algorithm for searching protein sequences (i.e., BLASTP), these studies use coarse-grained parallelism, where one sequence alignment is mapped to only one thread. Such an approach does not efficiently utilize the capabilities of a GPU, particularly due to the irregularity of BLASTP in both execution paths and memory-access patterns. To address the above shortcomings, we present a fine-grained approach to parallelize BLASTP, where each individual phase of sequence search is mapped to many threads on a GPU. This approach, which we refer to as cuBLASTP, reorders data-access patterns and reduces divergent branches of the most time-consuming phases (i.e., hit detection and ungapped extension). In addition, cuBLASTP optimizes the remaining phases (i.e., gapped extension and alignment with trace back) on a multicore CPU and overlaps their execution with the phases running on the GPU.

  13. Inflationary Phase with Time Varying Fundamental Constants

    CERN Document Server

    Berman, M S; Berman, Marcelo S.; Trevisan, Luis A.

    2002-01-01

    Following Barrow, and Barrow and collaborators, we find a cosmological JBD model, with varying speed of light and varying fine structure constant, where the deceleration parameter is -1,causing acceleration of the Universe.Indeed, we have an exponential inflationary phase. Plancks time, energy, length,etc.,might have had different numerical values in the past, than those available in the litterature, due to the varying values for speed of light, and gravitational constant.

  14. Mercury speciation and fine particle size distribution on combustion of Chinese coals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei; Wang, Shuxiao; Hao, Jiming [Tsinghua Univ., Beijing (China). Dept. of Environmental Science and Engineering and State Key Joint Lab. of Environment Simulation and Pollution Control; Daukoru, Michael; Torkamani, Sarah; Biswas, Pratim [Washington Univ., St. Louis, MO (United States). Aerosol and Air Quality Research Lab.

    2013-07-01

    Coal combustion is the dominant anthropogenic mercury emission source of the world. Electrostatic precipitator (ESP) can remove almost all the particulate mercury (Hg{sub p}), and wet flue gas desulfurization (WFGD) can retain a large part of the gaseous oxidized mercury (Hg{sup 2+}). Only a small percentage of gaseous elemental mercury (Hg{sup 0}) can be abated by the air pollution control devices (APCDs). Therefore, the mercury behavior across APCDs largely depends on the mercury speciation in the flue gas exhausting from the coal combustor. To better understand the formation process of three mercury species, i.e. Hg{sup 0}, Hg{sup 2+} and Hg{sub p}, in gaseous phase and fine particles, bench-scale measurements for the flue gas exhausting from combustion of different types of coal in a drop-tube furnace set-up, were carried out. It was observed that with the limitation of reaction kinetics, higher mercury concentration in flue gas will lead to lower Hg{sup 2+} proportion. The concentration of chlorine has the opposite effect, not as significantly as that of mercury though. With the chlorine concentration increasing, the proportion of Hg{sup 2+} increases. Combusting the finer coal powder results in the formation of more Hg{sup 2+}. Mineral composition of coal and coal particle size has a great impact on fine particle formation. Al in coal is in favor of finer particle formation, while Fe in coal can benefit the formation of larger particles. The coexistence of Al and Si can strengthen the particle coagulation process. This process can also be improved by the feeding of more or finer coal powder. The oxy-coal condition can make for both the mercury oxidation process and the metal oxidation in the fine particle formation process.

  15. Dynamics of flare processes and variety of the fine structure of solar radio emission over a wide frequency range of 30 - 7000 MHz

    CERN Document Server

    Chernov, Gennady; Tan, Baolin; Yan, Yihua; Tan, Chengming; Fu, Qijun

    2014-01-01

    Radiobursts exibiting fine structure observed over two years during the rising phase of Cycle 24 by the SBRS are analyzed. In five events zebra structure, various fiber bursts and fast pulsations were observed. Events on 15 and 24 February 2011 are of the greatest interest. The polarization of radio emission in all three cases is related to the ordinary wave mode of radio emission.Almost all events in the microwave range contain superfine structure. It is possible that each type of fine structure is excited by the same mechanism, and the broad variety of events is related to the dynamics of flare processes.

  16. Crystallization and Microstructure of Li2O-Al2O3-SiO2 Glass-ceramics Produced with Environmentally Acceptable Fining Agents

    Institute of Scientific and Technical Information of China (English)

    GUO Xingzhong; CAI Xiaobo; SONG Jie; YANG Hui

    2015-01-01

    Lithium aluminosilicate (LAS) glass-ceramics with a few gas bubbles were prepared when SnO2, V2O5 and CeO2 were used as fining agents. The effect of the complex fining agent on the crystallization, phase compositions and microstructure of LAS glass–ceramics was investigated by differential thermal analysis, X-ray diffraction and scanning electron microscopy, respectively. The results show that the introduction of fining agents promotes the crystallization at a lower temperature and has little effect on the compositions of main crystalline phase and microstructure when the crys-talline phase remainsβ-quartz. The special colors of LAS glass-ceramics can be obtained by controlling the crystalliza-tion temperature and the amounts of V2O5 and CeO2. The complex fining agent is an environmentally friendly alternative to toxic As2O3 and can be also used as a colorant for colored LAS glass-ceramics.

  17. DETECTION OF A FINE-SCALE DISCONTINUITY OF PHOTOSPHERIC MAGNETIC FIELDS ASSOCIATED WITH SOLAR CORONAL LOOP BRIGHTENINGS

    Energy Technology Data Exchange (ETDEWEB)

    Song, Donguk; Chae, Jongchul; Park, Soyoung [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Cho, Kyung-Suk; Lim, Eun-Kyung [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Ahn, Kwangsu; Cao, Wenda [Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City, CA 92314 (United States)

    2015-09-10

    We present the transient brightening of a coronal loop and an associated fine-scale magnetic discontinuity detected in the photosphere. Utilizing the high-resolution data taken with the Fast Imaging Solar Spectrograph and InfraRed Imaging Magnetograph of the New Solar Telescope at Big Bear Solar Observatory, we detect a narrow lane of intense horizontal magnetic field representing a magnetic discontinuity. It was visible as a dark lane partially encircling a pore in the continuum image, and was located near one of the footpoints of a small coronal loop that experienced transient brightenings. The horizontal field strength gradually increased before the loop brightening, and then rapidly decreased in the impulsive phase of the brightening, suggesting the increase of the magnetic non-potentiality at the loop footpoint and the sudden release of magnetic energy via magnetic reconnection. Our results support the nanoflare theory that coronal heating events are caused by magnetic reconnection events at fine-scale magnetic discontinuities.

  18. Improving fine motor activities of people with disabilities by using the response-stimulation strategy with a standard keyboard.

    Science.gov (United States)

    Chang, Man-Ling; Shih, Ching-Hsiang

    2014-08-01

    The principle of this study was to use the finger-pressing position detection program (FPPDP) with a standard keyboard to improve the fine motor activities of disabled people through environmental stimulation. The FPPDP is a software solution which turns a standard keyboard into a finger-pressing position detector. By using this technique, this study tried to find out whether two students with developmental disabilities would be able to effectively perform fine motor activities through the triggering of environmental stimulation. This study was based on an ABAB design and the results showed that both participants demonstrated an obvious increase in terms of their willingness to perform target responses during the intervention phases. The practical and developmental implications of the findings are discussed.

  19. Fine structure of fields in 2D photonic crystal waveguides

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Volkov, V. S.; Bozhevolnyi, S. I.

    2006-01-01

    We resolve fine structure of fields in a single-row missing photonic crystal waveguide by finite-difference time-domain modelling and SNOM measurements. Both linear dispersion and slow-light regimes in proximity of the cutoff are addressed in the analysis....

  20. [Starting with camphor--the progress of Nippon Fine Chemical].

    Science.gov (United States)

    Kimura, Osamu

    2010-01-01

    In 1918, Nippon Fine Chemical Co., Ltd. (NFC) was founded under the name, Nippon Camphor Co., Ltd. for the purpose of unifying the camphor business throughout Japan. The company manufactured purified camphor as a government-monopolized good. Camphor was used as a plasticizer for nitrocellulose, as a moth repellent, as an antimicrobial substance, as a rust inhibitor, and as an active ingredient in medicine. It was also a very important good exported in order to obtain foreign currency. Later on, after World War II and the abolition of the camphor monopoly, the company started manufacturing products related to oils and fats, including higher fatty acids, and expanded its business by developing a new field of chemical industry. In 1971 the company changed its name to Nippon Fine Chemical Co., Ltd., and made a new start as a diversified fine chemicals company. Recently, the fine chemicals division of NFC has concentrated on rather complex molecules, such as active pharmaceutical ingredients, and other chemicals. Since 2000, NFC have started to supply "Presome", precursors of liposome DDS drugs. NFC is strengthening marketing strategies in foreign countries with unique technologies and products.