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Sample records for akari nep-deep field

  1. Clustering of the AKARI NEP Deep Field mid infrared selected galaxies

    NASA Astrophysics Data System (ADS)

    Solarz, Aleksandra; Pollo, Agnieszka; Takeuchi, Tsutomu T.; Małek, Katarzyna

    2016-06-01

    We present a method of selection of 24 μm galaxies from the AKARI North Ecliptic Pole (NEP) Deep Field and measurements of their two-point correlation function. We aim to associate different 24 μm selected galaxy populations with present day galaxies, and to investigate the impact of their environment on the direction of their subsequent evolution. We discuss the use of Support Vector Machines (SVM) algorithms applied to infrared photometric data to perform star-galaxy separation, in which we achieve an accuracy > 80%. We explore the redshift dependance of the correlation function parameters as well as the linear bias evolution (which relates galaxy distribution to the one of the underlying dark matter). We find that the bias parameter increases slowly with redshift, from b = 0.9 at z < 0.5 to b ˜ 1.9 at z ˜ 1.1. Total infrared luminosities (L_{TIR}) found for different samples, suggest that galaxies with higher L_{TIR} do not necessarily reside in higher mass dark matter halos. We find that luminous infrared galaxies (LIRGs) at z˜1 can be ancestors of present day L_{*} early type galaxies.

  2. OT1_sserje01_1: THE HERSCHEL-AKARI NEP DEEP SURVEY: the cosmological history of stellar mass assembly and black hole accretion

    NASA Astrophysics Data System (ADS)

    Serjeant, S.

    2010-07-01

    We propose a far-IR and submm mapping survey of the premier AKARI deep field in the North Ecliptic Pole, in PACS/SPIRE parallel mode. This is the only major deep infrared field not yet covered by Herschel guaranteed or open time key projects. The outstanding and unparalleled continuous mid-IR photometric coverage from AKARI, far better than equivalent Spitzer surveys, enables a wide range of galaxy evolution diagnostics unachievable in any other survey field (including Herschel HerMES/PEP fields), by spanning the wavelengths of redshifted PAH and silicate features and the peak energy output of AGN dust tori. The investment by AKARI in the NEP represents ~10 percent of the entire pointed observations available throughout the lifetime of AKARI. Our proposal remedies the remarkable omission from Herschel's legacy surveys of the premier extragalactic deep field from another IR space telescope. We will simultaneously identify and find photometric redshifts for the Herschel point source population, make stacking analysis detections of the galaxies which dominate the submm extragalactic background light as a function of redshift, determine the bolometric power outputs of the galaxies that dominate the submm background, compare the UV/optical/mid-IR continuum/PAH/far-IR/submm/radio star formation rate estimator in the most comprehensive IR survey data set to date, and track the coupled stellar mass assembly and black hole accretion throughout most of the history of the Universe.

  3. OT2_sserje01_2: THE HERSCHEL-AKARI NEP DEEP SURVEY: the cosmological history of stellar mass assembly and black hole accretion

    NASA Astrophysics Data System (ADS)

    Serjeant, S.

    2011-09-01

    We propose a far-IR and submm mapping survey of the premier AKARI deep field in the North Ecliptic Pole, in PACS/SPIRE parallel mode. This is the only major deep infrared field not yet covered by Herschel guaranteed or open time key projects. The outstanding and unparalleled continuous mid-IR photometric coverage from AKARI, far better than equivalent Spitzer surveys, enables a wide range of galaxy evolution diagnostics unachievable in any other survey field (including Herschel HerMES/PEP fields), by spanning the wavelengths of redshifted PAH and silicate features and the peak energy output of AGN dust tori. The investment by AKARI in the NEP represents ~10 percent of the entire pointed observations available throughout the lifetime of AKARI. Our proposal remedies the remarkable omission from Herschel's legacy surveys of the premier extragalactic deep field from another IR space telescope. We will simultaneously identify and find photometric redshifts for the Herschel point source population, make stacking analysis detections of the galaxies which dominate the submm extragalactic background light as a function of redshift, determine the bolometric power outputs of the galaxies that dominate the submm background, compare the UV/optical/mid-IR continuum/PAH/far-IR/submm/radio star formation rate estimator in the most comprehensive IR survey data set to date, and track the coupled stellar mass assembly and black hole accretion throughout most of the history of the Universe. In OT1 the HOTAC concluded "The science output from the proposed survey will be outstanding [...] The panel was convinced that these observations should be done" but it since became clear that priority 2 time is very unlikely to be executed, so we request reclassification to priority 1.

  4. AKARI OBSERVATION OF THE SUB-DEGREE SCALE FLUCTUATION OF THE NEAR-INFRARED BACKGROUND

    SciTech Connect

    Seo, H. J.; Lee, Hyung Mok; Lee, Myung Gyoon; Matsumoto, T.; Jeong, W.-S.; Pyo, J.

    2015-07-10

    We report spatial fluctuation analysis of the sky brightness in the near-infrared from observations toward the north ecliptic pole (NEP) by the AKARI at 2.4 and 3.2 μm. As a follow-up study of our previous work on the Monitor field of AKARI, we used NEP deep survey data, which covered a circular area of about 0.4 square degrees, in order to extend fluctuation analysis at angular scales up to 1000″. We found residual fluctuation over the estimated shot noise at larger angles than the angular scale of the Monitor field. The excess fluctuation of the NEP deep field smoothly connects with that of the Monitor field at angular scales of a few hundred arcseconds and extends without any significant variation to larger angular scales up to 1000″. By comparing excess fluctuations at two wavelengths, we confirm a blue spectral feature similar to the result of the Monitor field. We find that the result of this study is consistent with Spitzer Space Telescope observations at 3.6 μm. The origin of the excess fluctuation in the near-infrared background remains to be determined, but we could exclude zodiacal light, diffuse Galactic light, and unresolved faint galaxies at low redshift based on the comparison with mid- and far-infrared brightness, ground-based near-infrared images.

  5. Optical/NIR Imaging of AKARI NEP-Wide Survey Field

    NASA Astrophysics Data System (ADS)

    Jeon, Y.; Im, M.; Kang, E.; Lee, I.; Ibrahimov, M.

    2009-12-01

    We describe the characteristics of optical and NIR imaging data of the NEP-Wide field in B, R, I, J and H band filters. The NEP-Wide is an AKARI survey of the North Ecliptic Pole covering 5.8 deg2 area. Our optical/NIR imaging observation supports the AKARI’s IR imaging data by providing a crucial coverage in optical/NIR. The optical data were obtained at Maidanak Observatory in Uzbekistan using the 1.5m telescope and the Seoul National University’s 4k×4k CCD. The NIR data were obtained using FLAMINGOS on KPNO 2.1m telescope. We present the astrometric accuracy, galaxy number counts and completeness. The photometric data will be used for identifying optical counterparts of the IR data provided by AKARI, studying their SEDs and the selection of interesting objects for spectroscopic follow-up studies.

  6. Optical Survey with KMTNet for Dusty Star-Forming Galaxies in the Akari Deep Field South

    NASA Astrophysics Data System (ADS)

    Jeong, Woong-Seob; Ko, Kyeongyeon; Kim, Minjin; Ko, Jongwan; Kim, Sam; Pyo, Jeonghyun; Kim, Seong Jin; Kim, Taehyun; Seo, Hyun Jong; Park, Won-Kee; Park, Sung-Joon; Kim, Min Gyu; Kim, Dong Jin; Cha, Sang-Mok; Lee, Yongseok; Lee, Chung-Uk; Kim, Seung-Lee; Matsuura, Shuji; Pearson, Chris; Matsuhara, Hideo

    2016-10-01

    We present an optical imaging survey of AKARI Deep Field South (ADF-S) using the Korea Microlensing Telescope Network (KMTNet), to find optical counterparts of dusty star-forming galaxies. The ADF-S is a deep far-infrared imaging survey region with AKARI covering around 12 deg^2, where the deep optical imaging data are not yet available. By utilizing the wide-field capability of the KMTNet telescopes (˜4 deg^2), we obtain optical images in B, R and I bands for three regions. The target depth of images in B, R and I bands is ˜24 mag (AB) at 5σ, which enables us to detect most dusty star-forming galaxies discovered by AKARI in the ADF-S. Those optical datasets will be helpful to constrain optical spectral energy distributions as well as to identify rare types of dusty star-forming galaxies such as dust-obscured galaxy, sub-millimeter galaxy at high redshift.}

  7. J- AND H-BAND IMAGING OF AKARI NORTH ECLIPTIC POLE SURVEY FIELD

    SciTech Connect

    Jeon, Yiseul; Im, Myungshin; Kang, Eugene; Lee, Hyung Mok; Matsuhara, Hideo E-mail: mim@astro.snu.ac.kr

    2014-10-01

    We present the J- and H-band source catalog covering the AKARI North Ecliptic Pole field. Filling the gap between the optical data from other follow-up observations and mid-infrared (MIR) data from AKARI, our near-infrared (NIR) data provides contiguous wavelength coverage from optical to MIR. For the J- and H-band imaging, we used the FLoridA Multi-object Imaging Near-ir Grism Observational Spectrometer on the Kitt Peak National Observatory 2.1m telescope covering a 5.1 deg{sup 2} area down to a 5σ depth of ∼21.6 mag and ∼21.3 mag (AB) for the J and H bands with an astrometric accuracy of 0.''14 and 0.''17 for 1σ in R.A. and decl. directions, respectively. We detected 208,020 sources for the J band and 203,832 sources for the H band. This NIR data is being used for studies including the analysis of the physical properties of infrared sources such as stellar mass and photometric redshifts, and will be a valuable data set for various future missions.

  8. Where The Active Galaxies Live: A Panchromatic View Of AGN In The Akari-NEP Field

    NASA Astrophysics Data System (ADS)

    Karouzos, Marios; Im, M.; Takagi, T.; Shim, H.; Ko, J.; Matsuhara, H.; Braun, R.; White, G.; Serjeant, S.

    2012-05-01

    We study the host galaxy properties of radio-detected sources in the AKARI-NEP field, using an ensemble of multi-wavelength datasets that range from the far-UV to the radio. Using both photometry and spectroscopy, we identify both radio-loud and radio-quiet AGN and study their host galaxy properties, including the age of their stellar populations, current star-formation rates, as well as their morphology. Using this information we investigate the role of AGN within the currently accepted framework of a merger-driven evolution of galaxies. This research was supported through the Creative Research Initiative program, No. 2010-0000712, of the National Research Foundation of Korea (NRFK) funded by the Korea government(MEST).

  9. Dust attenuation up to z ≃ 2 in the AKARI North Ecliptic Pole Deep Field

    NASA Astrophysics Data System (ADS)

    Buat, V.; Oi, N.; Heinis, S.; Ciesla, L.; Burgarella, D.; Matsuhara, H.; Malek, K.; Goto, T.; Malkan, M.; Marchetti, L.; Ohyama, Y.; Pearson, C.; Serjeant, S.; Miyaji, T.; Krumpe, M.; Brunner, H.

    2015-05-01

    Aims: We aim to study the evolution of dust attenuation in galaxies selected in the infrared (IR) in the redshift range in which they are known to dominate the star formation activity in the universe. The comparison with other measurements of dust attenuation in samples selected using different criteria will give us a global picture of the attenuation at work in star-forming galaxies and its evolution with redshift. Methods: We selected galaxies in the mid-IR from the deep survey of the North Ecliptic Field performed by the AKARI satellite. Using multiple filters of IRC instrument, we selected more than 4000 galaxies from their rest-frame emission at 8 μm, from z ≃ 0.2 to ~2. We built spectral energy distributions from the rest-frame ultraviolet (UV) to the far-IR by adding ancillary data in the optical-near IR and from GALEX and Herschel surveys. We fit spectral energy distributions with the physically-motivated code CIGALE. We test different templates for active galactic nuclei (AGNs) and recipes for dust attenuation and estimate stellar masses, star formation rates, amount of dust attenuation, and AGN contribution to the total IR luminosity. We discuss the uncertainties affecting these estimates on a subsample of galaxies with spectroscopic redshifts. We also define a subsample of galaxies with an IR luminosity close to the characteristic IR luminosity at each redshift and study the evolution of dust attenuation of this selection representative of the bulk of the IR emission. Results: The AGN contribution to the total IR luminosity is found to be on average approximately 10%, with a slight increase with redshift. The determination of AGN contribution does not depend significantly on the assumed AGN templates except for galaxies detected in X-ray. The choice of attenuation law has a marginal impact on the determination of stellar masses and star formation rates. Dust attenuation in galaxies dominating the IR luminosity function is found to increase from z = 0

  10. [Ultra] luminous infrared galaxies selected at 90 μm in the AKARI deep field: a study of AGN types contributing to their infrared emission

    NASA Astrophysics Data System (ADS)

    Małek, K.; Bankowicz, M.; Pollo, A.; Buat, V.; Takeuchi, T. T.; Burgarella, D.; Goto, T.; Malkan, M.; Matsuhara, H.

    2017-01-01

    Aims: The aim of this work is to characterize physical properties of ultra luminous infrared galaxies (ULIRGs) and luminous infrared galaxies (LIRGs) detected in the far-infrared (FIR) 90 μm band in the AKARI Deep Field-South (ADF-S) survey. In particular, we want to estimate the active galactic nucleus (AGN) contribution to the LIRGs and ULIRGs' infrared emission and which types of AGNs are related to their activity. Methods: We examined 69 galaxies at redshift ≥0.05 detected at 90 μm by the AKARI satellite in the ADF-S, with optical counterparts and spectral coverage from the ultraviolet to the FIR. We used two independent spectral energy distribution fitting codes: one fitting the SED from FIR to FUV (CIGALE) (we use the results from CIGALE as a reference) and gray-body + power spectrum fit for the infrared part of the spectra (CMCIRSED) in order to identify a subsample of ULIRGs and LIRGs, and to estimate their properties. Results: Based on the CIGALE SED fitting, we have found that LIRGs and ULIRGs selected at the 90 μm AKARI band compose 56% of our sample (we found 17 ULIRGs and 22 LIRGs, spanning over the redshift range 0.06

  11. VizieR Online Data Catalog: Optical catalog of AKARI NEP-wide survey (Jeon+, 2010)

    NASA Astrophysics Data System (ADS)

    Jeon, Y.; Im, M.; Ibrahimov, M.; Lee, H. M.; Lee, I.; Lee, M. G.

    2010-09-01

    The AKARI NEP-Wide field is centered at 18:00:00+66:36:00 covering a circular area of 5.8deg2. The images were obtained in Bessell B, R, and I filters from 2007 June 12 to August 5 at the Maidanak Observatory in Uzbekistan, using the Seoul National University 4kx4k Camera (SNUCAM) on the 1.5m Richey-Chretien, AZT-22 telescope. (1 data file).

  12. AKARI-CAS—Online Service for AKARI All-Sky Catalogues

    NASA Astrophysics Data System (ADS)

    Yamauchi, C.; Fujishima, S.; Ikeda, N.; Inada, K.; Katano, M.; Kataza, H.; Makiuti, S.; Matsuzaki, K.; Takita, S.; Yamamoto, Y.; Yamamura, I.; Ishihara, D.; Oyabu, S.

    2011-07-01

    The AKARI All-Sky Catalogues are an important infrared astronomical database for next-generation astronomy that take over the IRAS catalog. We have developed an online service, AKARI Catalogue Archive Server (AKARI-CAS), for astronomers. The service includes useful and attractive search tools and visual tools. One of the new features of AKARI-CAS is cached SIMBAD/NED entries, which can match AKARI catalogs with other catalogs stored in SIMBAD or NED. To allow advanced queries to the databases, direct input of SQL is also supported. In those queries, fast dynamic cross-identification between registered catalogs is a remarkable feature. In addition, multiwavelength quick-look images are displayed in the visualization tools, which will increase the value of the service. In the construction of our service, we considered a wide variety of astronomers’ requirements. As a result of our discussion, we concluded that supporting users’ SQL submissions is the best solution for the requirements. Therefore, we implemented an RDBMS layer so that it covered important facilities, including the whole processing of tables. We found that PostgreSQL is the best open-source RDBMS products for such purpose, and we wrote codes for both simple and advanced searches into the SQL stored functions. To implement such stored functions for fast radial search and cross-identification with minimum cost, we applied a simple technique that is not based on HTM or HEALPix. In contrast, the online application layer became compact and was written in simple procedural PHP codes. In total, our system realizes cost-effective maintenance and enhancements.

  13. AKARI Mid-Infrared All-sky Survey

    NASA Astrophysics Data System (ADS)

    Ishihara, D.; Onaka, T.; Kataza, H.; Fujiwara, H.; Takita, S.; Alfageme, C.; Cohen, M.; Fujishiro, N.; Garcia-Lario, P.; Hasegawa, S.; Ita, Y.; Kim, W.; Nakagawa, T.; Matsuhara, H.; Matsumoto, T.; Murakami, H.; Ohyama, Y.; Oyabu, S.; Pyo, J.; Sakon, I.; Salama, A.; Stephenson, C.; Shibai, H.; Tanabe, T.; Uemizu, K.; Ueno, M.; Usui, F.; Wada, T.; Watarai, H.; Yamauchi, C.; Yamamura, I.

    2009-08-01

    AKARI All-sky Survey observations were carried out in the mid- to far-infrared spectral region with six photometric bands during the cryogenic mission phase of AKARI from May 8, 2006 to August 26, 2007. This paper reports the mid-infrared part of the AKARI all-sky survey. It was carried out with two mid-infrared broad bands centered at 9 and 18 μm. More than 90 percent of entire sky was observed by both bands during this period. The 5σ sensitivities for point sources are about 50 and 120 mJy, respectively. The spatial resolution is better than 10'' at both bands. The AKARI mid-infrared survey achieved a deeper sensitivity and a finer spatial resolution than the previous IRAS survey, the AKARI mid-infrared survey has the sensitivity to detect a debris disk of β Pic at a distance of 100 pc and several new debris disk candidates have already been discovered at 18 μm in a preliminary study, separately discussed by Fujiwara et al. (in this volume). More debris disk candidates are expected to be found in further investigations, which will make a significant impact on the statistical study of debris disks.

  14. Ultraluminous infrared galaxies in the AKARI all-sky survey

    SciTech Connect

    Kilerci Eser, E.; Goto, T.; Doi, Y. E-mail: doi@ea.c.u-tokyo.ac.jp

    2014-12-10

    We present a new catalog of 118 ultraluminous infrared galaxies (ULIRGs) and one hyperluminous infrared galaxy (HLIRG) by cross-matching the AKARI all-sky survey with the Sloan Digital Sky Survey Data Release 10 (SDSS DR10) and the final data release of the Two-Degree Field Galaxy Redshift Survey. Forty of the ULIRGs and one HLIRG are new identifications. We find that ULIRGs are interacting pair galaxies or ongoing or postmergers. This is consistent with the widely accepted view: ULIRGs are major mergers of disk galaxies. We confirm the previously known positive trend between the active galactic nucleus fraction and infrared luminosity. We show that ULIRGs have a large offset from the main sequence up to z ∼ 1; their offset from the z ∼ 2 'main sequence' is relatively smaller. We find a result consistent with the previous studies showing that, compared to local star-forming SDSS galaxies of similar mass, local ULIRGs have lower oxygen abundances. We demonstrate for the first time that ULIRGs follow the fundamental metallicity relation (FMR). The scatter of ULIRGs around the FMR (0.09 dex-0.5 dex) is comparable to the scatter of z ∼ 2-3 galaxies. We provide the largest local (0.050

  15. AKARI NIR spectroscopy of interstellar ices

    NASA Astrophysics Data System (ADS)

    Onaka, Takashi; Mori, Tamami I.; Sakon, Itsuki; Usui, Fumihiko; Wu, Ronin; Shimonishi, Takashi

    2016-10-01

    The Infrared Camera (IRC) onboard AKARI has a near-infrared (2-5μm) spectroscopic capability with high sensitivity that allows us to study the major ice components in various objects. In particular, H2O and CO2 ice absorption features have been detected towards nearby galaxies, including several young stellar objects (YSOs) in the Large Magellanic Cloud (LMC), as well as a number of HII region-PDR complexes for the first time by IRC spectroscopy. While observations in the LMC show a high ratio (~0.34) of the CO2 to H2O ice column densities, the ratios in Galactic HII-region-PDR complexes are in the range of 0.1-0.2, being compatible with those found in Galactic massive YSOs in previous studies. The good correlation supports concurrent formation of the two ice species on the grain surface and the higher ratio in the low-metallicity LMC suggests possible environmental effects in the formation process.

  16. AKARI far-infrared maps of the zodiacal dust bands

    NASA Astrophysics Data System (ADS)

    Ootsubo, Takafumi; Doi, Yasuo; Takita, Satoshi; Nakagawa, Takao; Kawada, Mitsunobu; Kitamura, Yoshimi; Matsuura, Shuji; Usui, Fumihiko; Arimatsu, Ko

    2016-06-01

    Zodiacal emission is thermal emission from interplanetary dust. Its contribution to the sky brightness is non-negligible in the region near the ecliptic plane, even in the far-infrared (far-IR) wavelength regime. We analyze zodiacal emission observed by the AKARI far-IR all-sky survey, which covers 97% of the entire sky at arcminute-scale resolution in four photometric bands, with central wavelengths of 65, 90, 140, and 160 μm. AKARI detected small-scale structures in the zodiacal dust cloud, including the asteroidal dust bands and the circumsolar ring, at far-IR wavelengths. Although the smooth component of the zodiacal emission structure in the far-IR sky can be reproduced well by models based on existing far-IR observations, previous zodiacal emission models have discrepancies in the small-scale structures compared with observations. We investigate the geometry of the small-scale dust-band structures in the AKARI far-IR all-sky maps and construct template maps of the asteroidal dust bands and the circumsolar ring components based on the AKARI far-IR maps. In the maps, ± 1.4°, ± 2.1°, and ± 10° asteroidal dust-band structures are detected in the 65 μm and 90 μm bands. A possible ± 17° band may also have been detected. No evident dust-band structures are identified in either the 140 μm or the 160 μm bands. By subtracting the dust-band templates constructed in this paper, we can achieve a similar level of flux calibration of the AKARI far-IR all-sky maps in the |β| < 40° region to that in the region for |β| > 40°.

  17. Networks of Absolute Calibration Stars for SST, AKARI, and WISE

    NASA Astrophysics Data System (ADS)

    Cohen, M.

    2007-04-01

    I describe the Cohen-Walker-Witteborn (CWW) network of absolute calibration stars built to support ground-based, airborne, and space-based sensors, and how they are used to calibrate instruments on the SPITZER Space Telescope (SST and Japan's AKARI (formerly ASTRO-F), and to support NASA's planned MidEx WISE (the Wide-field Infrared Survey Explorer). All missions using this common calibration share a self-consistent framework embracing photometry and low-resolution spectroscopy. CWW also underpins COBE/DIRBE several instruments used on the Kuiper Airborne Observatory ({KAO}), the joint Japan-USA ``IR Telescope in Space" (IRTS) Near-IR and Mid-IR spectrometers, the European Space Agency's IR Space Observatory (ISO), and the US Department of Defense's Midcourse Space eXperiment (MSX). This calibration now spans the far-UV to mid-infrared range with Sirius (one specific Kurucz synthetic spectrum) as basis, and zero magnitude defined from another Kurucz spectrum intended to represent an ideal Vega (not the actual star with its pole-on orientation and mid-infrared dust excess emission). Precision 4-29 μm radiometric measurements on MSX validate CWW's absolute Kurucz spectrum of Sirius, the primary, and a set of bright K/MIII secondary standards. Sirius is measured to be 1.0% higher than predicted. CWW's definitions of IR zero magnitudes lie within 1.1% absolute of MSX measurements. The US Air Force Research Laboratory's independent analysis of on-orbit {MSX} stellar observations compared with emissive reference spheres show CWW primary and empirical secondary spectra lie well within the ±1.45% absolute uncertainty associated with this 15-year effort. Our associated absolute calibration for the InfraRed Array Camera (IRAC) on the SST lies within ˜2% of the recent extension of the calibration of the Hubble Space Telescope's STIS instrument to NICMOS (Bohlin, these Proceedings), showing the closeness of these two independent approaches to calibration.

  18. Search for Water in Outer Main Belt Based on AKARI Asteroid Catalog

    NASA Astrophysics Data System (ADS)

    Usui, Fumihiko

    2012-06-01

    We propose a program to search water ice on the surface of asteroids in the outer main belt regions, which have high albedo measured with AKARI. The distribution of water in the main belt provides important information to understanding of the formation and evolution of the solar system, because water is a good indicator of temperature in the early solar nebula. The existence of water ice is a hot topic in the solar system studies today. Water ice is recently found in the outer region of the main asteroid belt and some of them are linked to the main belt comets. Brand-new albedo data brought by AKARI opens the possibility of detection of water ice on the C-type asteroids. Here we propose to make the spectroscopic observations with the Subaru telescope in the near-infrared wavelengths to detect water ice on these high-albedo C-type asteroids. Thanks to a large aperture of Subaru telescope and a high altitude of Mauna Kea, it can be only possible to observe a weak signal of the existence of water on the surface of asteroids with a certain S/N. In addition, using the imaging data taken prior to IRCS spectroscopic mode, we intend to seek any comet-like activities by investigating diffuseness of the asteroids, which can be detected by comparing the observed point-spread functions with those of field stars.

  19. Summary of observations of the infrared camera (IRC) onboard AKARI

    NASA Astrophysics Data System (ADS)

    Onaka, T.; Matsuhara, H.; Wada, T.; Ishihara, D.; Ohyama, Y.; Sakon, I.; Shimonishi, T.; Ohsawa, R.; Mori, T. I.; Egusa, F.; Usui, F.; Takita, S.; Murakami, H.; Oyabu, S.; Yamagishi, M.; Mori, T.; Mouri, A.; Kondo, T.; Suzuki, S.; Kaneda, H.; Ita, Y.; Ootsubo, T.

    2012-09-01

    AKARI, the Japanese satellite mission dedicated to infrared astronomy was launched in 2006 February and exhausted its liquid helium in 2007 August. During the cold mission phase, the Infrared Camera (IRC) onboard carried out an all-sky survey at 9 and 18µm with better spatial resolution and higher sensitivity than IRAS. Both bands also have slightly shorter wavelength coverage than IRAS 12 and 25μm bands and thus provide different information on the infrared sky. All-sky image data of the IRC are now in the final processing and will be released to the public within a year. After the exhaustion of the cryogen, the telescope and focal plane instruments of AKARI had still been kept at sufficiently low temperatures owing to the onboard cryocooler. Near-infrared (NIR) imaging and spectroscopic observations with the IRC had continued until 2011 May, when the spacecraft had a serious problem in the power supply system that forced us to terminate the observation. The IRC carried out nearly 20000 pointing observations in total despite of its near-earth orbit. About a half of them were performed after the exhaustion of the cryogen in the spectroscopic modes, which provided high-sensitivity NIR spectra from 2 to 5µm without disturbance of the terrestrial atmosphere. During the warm mission phase, the temperature of the instrument gradually increased and changed the array operation conditions. We present a summary of AKARI/IRC observations, including the all-sky mid-infrared diffuse data as well as the data taken in the warm mission phase.

  20. The infrared all-sky survey mission AKARI

    NASA Astrophysics Data System (ADS)

    Murakami, Hiroshi

    The AKARI, Japanese infrared astronomical satellite, was launched on 2006 February 21 and started the observation in May of the same year. It has performed the all-sky survey at 6 wavelength bands in the midand far-infrared, as well as more than 5,000 pointing observations, during the main mission period lasted until the liquid helium exhaustion on 2007 August 26. The all-sky survey covered more than 90 % of the entire sky with much higher spatial resolution than the IRAS catalogues. First version of AKARI infrared source catalogue will be released in 2009. In the pointing observation, a wide variety of objects, from the solar-system objects to the cosmologically distant galaxies, were observed systematically in near to far infrared. The early results of the pointing observations has been published recently. We are now preparing the post-helium mission where the pointing observations only in the near-infrared wavelength range are be performed with the cooling by the Stirling-cycle coolers. It has been confirmed that the sensitivity of the near-infrared array is kept high, although its operation temperature is higher than that in the liquid-helium cooling. Here we report the overview of the mission, and highlights of the scientific results as well as the observation plan of the post-helium mission planned to start from April 2008.

  1. ASTRO-F/AKARI Observations of the Solar System Bodies

    NASA Astrophysics Data System (ADS)

    Ueno, Munetaka

    There are large and small bodies in our solar system, and are also other objects such as comets and dust particles, but we do not fully understand the linkage among themselves yet. To establish a concrete idea on the inter-planetary dust (IPD) cloud complex under the planetary system must be one of the most important issue, since the mechanism of continuous supply of interplanetary dust particle is still in the haze of the solar system. Big problem on the zodiacal dust cloud is its origin, since the lifetime of the interplanetary dust under the Poynting-Robertson drag is much shorter than the age of the Solar System. ASTRO-F/AKARI capabilities on good sensitivities for extended sources, better calibration accuracy, spatial resolutions and spectroscopy in middle infrared bands will open a new horizon for IPD studies. IRAS dramatically changed the smooth featureless picture of the zodiacal dust cloud by revealing numerous bands of asteroidal debris, several narrow trails of cometary dust, and a clumpy dust ring. However, problems of calibration drifting and half degree resolution hindered us from fully identifying dynamical origins of the IPD cloud complex in general and of the symmetry plane's tilt. COBE/DIRBE also mapped almost entire sky with a 0.7 arc-degree size beam and with better calibration, and confirmed the mean motion resonance (MMR) dust ring, and an isolation of the leading and trailing blobs in the MMR feature. The mission's coverage of the solar elongation angle is limited to very narrow span from 89 to 91 arc-degree but the mission has superbly high sensitivity and fine spatial resolution. A preliminary results of ASTRO- F/AKARI observations, and dedicated program for the study of the solar system bodies will be introduced in this presentation.

  2. AKARI NEAR-INFRARED SPECTROSCOPY OF LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Lee, Jong Chul; Lee, Myung Gyoon; Hwang, Ho Seong

    2012-09-01

    We present the AKARI near-infrared (NIR; 2.5-5 {mu}m) spectroscopic study of 36 (ultra)luminous infrared galaxies ((U)LIRGs) at z = 0.01-0.4. We measure the NIR spectral features including the strengths of 3.3 {mu}m polycyclic aromatic hydrocarbon emission and hydrogen recombination lines (Br{alpha} and Br{beta}), optical depths at 3.1 and 3.4 {mu}m, and NIR continuum slope. These spectral features are used to identify optically elusive, buried active galactic nuclei (AGNs). We find that half of the (U)LIRGs optically classified as non-Seyferts show AGN signatures in their NIR spectra. Using a combined sample of (U)LIRGs with NIR spectra in the literature, we measure the contribution of buried AGNs to the infrared luminosity from the spectral energy distribution fitting to the IRAS photometry. The contribution of these buried AGNs to the infrared luminosity is 5%-10%, smaller than the typical AGN contribution of (U)LIRGs including Seyfert galaxies (10%-40%). We show that NIR continuum slopes correlate well with WISE [3.4]-[4.6] colors, which would be useful for identifying a large number of buried AGNs using the WISE data.

  3. ASASSN-17dm: Discovery of A Probable Supernova in AKARI J1006572-474345

    NASA Astrophysics Data System (ADS)

    Kiyota, S.; Brimacombe, J.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W.-S.; Kochanek, C. S.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Cacella, P.; Koff, R. A.; Post, R. S.; Stone, G.

    2017-03-01

    During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014), using data from the quadruple 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new transient source, most likely a supernova, in the galaxy AKARI J1006572-474345.

  4. Brightness Map of the Zodiacal Emission from the AKARI IRC All-Sky Survey

    NASA Astrophysics Data System (ADS)

    Pyo, Jeonghyun; Ueno, Munetaka; Minn Kwon, Suk; Hong, Seung Soo; Ishihara, Daisuke; Ishiguro, Masateru; Usui, Fumihiko; Ootsubo, Takafumi; Mukai, Tadashi

    The Japanese infrared space mission AKARI successfully scanned the whole sky with its two main instruments, Infrared Camera (IRC) and Far-Infrared Surveyor (FIS). The AKARI All-Sky Survey provides us with an invaluable opportunity to examine the zodiacal emission (ZE) over the entire sky in both leading and trailing directions of the Earth's motion. We describe our efforts to reduce the ZE brightness map from AKARI's survey in the 9 µm waveband. The map is compared with the interplanetary dust (IPD) cloud model of Kelsall et al. (1998). From the comparison, we derived the emissivity modification factors at 9 µm for the smooth cloud, the dust bands, and the resonance ring components. The result requires to increase the contribution of the ring component to the ZE brightness by about 20%. The map of residual brightness after subtracting the model from the observation reveals three dust bands and the leading resonance blob, which are not implemented in the model. We paid special attention to the north and south ecliptic pole brightnesses. The symmetry plane's inclination and longitude of ascending node for the smooth cloud are modified from those in Kelsall et al. (1998) to make the best fit to the observed pole brightness difference. The analysis result indicates possible warping of the symmetry plane. We found that the average of the two pole brightnesses does not become the maximum at the Earth's perihelion, which is a probable evidence of the cloud's off-centering.

  5. MODELING OF THE ZODIACAL EMISSION FOR THE AKARI/IRC MID-INFRARED ALL-SKY DIFFUSE MAPS

    SciTech Connect

    Kondo, Toru; Ishihara, Daisuke; Kaneda, Hidehiro; Nakamichi, Keichiro; Takaba, Sachi; Kobayashi, Hiroshi; Ootsubo, Takafumi; Pyo, Jeonghyun; Onaka, Takashi E-mail: ishihara@u.phys.nagoya-u.ac.jp

    2016-03-15

    The zodiacal emission, which is the thermal infrared (IR) emission from the interplanetary dust (IPD) in our solar system, has been studied for a long time. Nevertheless, accurate modeling of the zodiacal emission has not been successful to reproduce the all-sky spatial distribution of the zodiacal emission, especially in the mid-IR where the zodiacal emission peaks. Therefore, we aim to improve the IPD cloud model based on Kelsall et al., using the AKARI 9 and 18 μm all-sky diffuse maps. By adopting a new fitting method based on the total brightness, we have succeeded in reducing the residual levels after subtraction of the zodiacal emission from the AKARI data and thus in improving the modeling of the zodiacal emission. Comparing the AKARI and the COBE data, we confirm that the changes from the previous model to our new model are mostly due to model improvements, but not temporal variations between the AKARI and the COBE epoch, except for the position of the Earth-trailing blob. Our results suggest that the size of the smooth cloud, a dominant component in the model, is about 10% more compact than previously thought, and that the dust sizes are not large enough to emit blackbody radiation in the mid-IR. Furthermore, we detect a significant isotropically distributed IPD component, owing to an accurate baseline measurement with AKARI.

  6. Modeling of the Zodiacal Emission for the AKARI/IRC Mid-infrared All-sky Diffuse Maps

    NASA Astrophysics Data System (ADS)

    Kondo, Toru; Ishihara, Daisuke; Kaneda, Hidehiro; Nakamichi, Keichiro; Takaba, Sachi; Kobayashi, Hiroshi; Ootsubo, Takafumi; Pyo, Jeonghyun; Onaka, Takashi

    2016-03-01

    The zodiacal emission, which is the thermal infrared (IR) emission from the interplanetary dust (IPD) in our solar system, has been studied for a long time. Nevertheless, accurate modeling of the zodiacal emission has not been successful to reproduce the all-sky spatial distribution of the zodiacal emission, especially in the mid-IR where the zodiacal emission peaks. Therefore, we aim to improve the IPD cloud model based on Kelsall et al., using the AKARI 9 and 18 μm all-sky diffuse maps. By adopting a new fitting method based on the total brightness, we have succeeded in reducing the residual levels after subtraction of the zodiacal emission from the AKARI data and thus in improving the modeling of the zodiacal emission. Comparing the AKARI and the COBE data, we confirm that the changes from the previous model to our new model are mostly due to model improvements, but not temporal variations between the AKARI and the COBE epoch, except for the position of the Earth-trailing blob. Our results suggest that the size of the smooth cloud, a dominant component in the model, is about 10% more compact than previously thought, and that the dust sizes are not large enough to emit blackbody radiation in the mid-IR. Furthermore, we detect a significant isotropically distributed IPD component, owing to an accurate baseline measurement with AKARI.

  7. AKARI and Spinning Dust: A look at microwave dust emission via the Infrared

    NASA Astrophysics Data System (ADS)

    Bell, Aaron Christopher; Onaka, Takashi; Wu, Ronin; Doi, Yasuo

    2015-08-01

    Rapidly spinning dust particles having a permanent electric dipole moment have been shown to be a likely carrier of the anomalous microwave emission (AME), a continuous excess of microwave flux in the 10 to 90 GHz range. Small grains, possibly polycyclic aromatic hydrocarbons (PAHs), are a leading suspect. Due to the overlap frequency overlap with the CMB, the AME is requiring cosmologists to consider the ISM with more care. ISM astronomers are also needing to consider the contribution of cosmological radiation to large-scale dust investigations. We present data from AKARI/Infrared Camera (IRC) due to the effective PAH band coverage of its 9 um survey to investigate PAH emission within 98 AME candidate regions identified by Planck Collaboration et al. (2014). We supplement AKARI data with the four Infrared Astronomical Satellite (IRAS) all-sky maps and complement with the Planck High Frequency Instrument (HFI) bands at 857 and 545GHz to constrain the full dust SED. We sample analyse the SEDs of all 98 regions. We utilize all 7 AKARI photometric bands, as well as the 4 IRAS bands and 2 HFI. We carry out a modified blackbody fitting, and estimate the optical depth of thermal dust at 250 um, and compare this to AME parameters. We also show plots of each band's average intensity for all 98 regions vs. AME parameters. We find a positive trend between the optical depth and AME. In the band-by-band comparison the AKARI 9 um intensity shows a weaker trend with AME. In general, the MIR correlates less strongly with AME than the FIR. The optical depth vs. AME trend improves slightly when looking only at significant AME regions. Scaling the IR intensities by the ISRF strength G0 does not improve the correlations. We cannot offer strong support of a spinning dust model. The results highlight the need for full dust SED modelling, and for a better understanding of the role that magnetic dipole emission from dust grains could play in producing the AME.

  8. On the Radii of Brown Dwarfs Measured with AKARI Near-infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sorahana, S.; Yamamura, I.; Murakami, H.

    2013-04-01

    We derive the radii of 16 brown dwarfs observed by AKARI using their parallaxes and the ratios of observed to model fluxes. We find that the brown dwarf radius ranges between 0.64-1.13 RJ with an average radius of 0.83 RJ . We find a trend in the relation between radii and T eff; the radius is at a minimum at T eff ~ 1600 K, which corresponds to the spectral types of mid- to late-L. The result is interpreted by a combination of radius-mass and radius-age relations that are theoretically expected for brown dwarfs older than 108 yr.

  9. Efficient Selection and Classification of Infrared Excess Emission Stars Based on AKARI and 2MASS Data

    NASA Astrophysics Data System (ADS)

    Li, Jinzeng; Huang, Yafang

    2015-08-01

    The selection of young stellar objects (YSOs) based on excessive emission in the infrared is easily contaminated by post-main-sequence stars and various types of emission line stars with similar properties. We define here stringent criteria for an efficient selection and classification of stellar sources with infrared excess emission based on combined 2MASS and AKARI colors. First of all, bright dwarfs and giants with known spectral types were selected from the Hipparcos Catalogue and cross-identified with the 2MASS and AKARI Point Source Catalogues to produce the main-sequence and the post-main-sequence tracks, which appear as expected as tight tracks with very small dispersion. However, several of the main-sequence stars indicate excess emission in the color space. Further investigations based on the SIMBAD data help to clarify their nature as classical Be stars, which are found to be located in a well isolated region on each of the color-color (C-C) diagrams. Several kinds of contaminants were then removed based on their distribution on the C-C diagrams. A test sample of Herbig Ae/Be stars and classical T Tauri stars were cross-identified with the 2MASS and AKARI catalogs to define the loci of YSOs with different masses on the C-C diagrams. Well classified Class I and Class II sources were taken as a second test sample to discriminate between various types of YSOs at possibly different evolutionary stages. This helped to define the loci of different types of YSOs and a set of criteria for selecting YSOs based on their colors in the near- and mid-infrared. Candidate YSOs toward IC 1396 indicating excess emission in the near-infrared were employed to verify the validity of the new source selection criteria defined based on C-C diagrams compiled with the 2MASS and AKARI data. Optical spectroscopy and spectral energy distributions of the IC 1396 sample yield a clear identification of the YSOs and further confirm the criteria defined for exploring the nature and

  10. Efficient Selection and Classification of Infrared Excess Emission Stars Based on AKARI and 2MASS Data

    NASA Astrophysics Data System (ADS)

    Huang, Ya Fang; Zeng Li, Jin; Rector, Travis A.; Mallamaci, Carlos C.

    2013-05-01

    The selection of young stellar objects (YSOs) based on excess emission in the infrared is easily contaminated by post-main-sequence stars and various types of emission line stars with similar properties. We define in this paper stringent criteria for an efficient selection and classification of stellar sources with infrared excess emission based on combined Two Micron All Sky Survey (2MASS) and AKARI colors. First of all, bright dwarfs and giants with known spectral types were selected from the Hipparcos Catalogue and cross-identified with the 2MASS and AKARI Point Source Catalogues to produce the main-sequence and the post-main-sequence tracks, which appear as expected as tight tracks with very small dispersion. However, several of the main-sequence stars indicate excess emission in the color space. Further investigations based on the SIMBAD data help to clarify their nature as classical Be stars, which are found to be located in a well isolated region on each of the color-color (C-C) diagrams. Several kinds of contaminants were then removed based on their distribution in the C-C diagrams. A test sample of Herbig Ae/Be stars and classical T Tauri stars were cross-identified with the 2MASS and AKARI catalogs to define the loci of YSOs with different masses on the C-C diagrams. Well classified Class I and Class II sources were taken as a second test sample to discriminate between various types of YSOs at possibly different evolutionary stages. This helped to define the loci of different types of YSOs and a set of criteria for selecting YSOs based on their colors in the near- and mid-infrared. Candidate YSOs toward IC 1396 indicating excess emission in the near-infrared were employed to verify the validity of the new source selection criteria defined based on C-C diagrams compiled with the 2MASS and AKARI data. Optical spectroscopy and spectral energy distributions of the IC 1396 sample yield a clear identification of the YSOs and further confirm the criteria defined

  11. AKARI AND BLAST OBSERVATIONS OF THE CASSIOPEIA A SUPERNOVA REMNANT AND SURROUNDING INTERSTELLAR MEDIUM

    SciTech Connect

    Sibthorpe, B.; Ade, P. A. R.; Griffin, M.; Hargrave, P. C.; Mauskopf, P.; Bock, J. J.; Chapin, E. L.; Halpern, M.; Marsden, G.; Devlin, M. J.; Dicker, S.; Klein, J.; Gundersen, J. O.; Hughes, D. H.; Jeong, W.-S.; Kaneda, H.; Koo, B.-C.; Lee, H.-G.; Martin, P. G.; Moon, D.-S.

    2010-08-20

    We use new large area far infrared maps ranging from 65 to 500 {mu}m obtained with the AKARI and the Balloon-borne Large Aperture Submillimeter Telescope missions to characterize the dust emission toward the Cassiopeia A supernova remnant (SNR). Using the AKARI high-resolution data we find a new 'tepid' dust grain population at a temperature of {approx}35 K and with an estimated mass of 0.06 M{sub sun}. This component is confined to the central area of the SNR and may represent newly formed dust in the unshocked supernova ejecta. While the mass of tepid dust that we measure is insufficient by itself to account for the dust observed at high redshift, it does constitute an additional dust population to contribute to those previously reported. We fit our maps at 65, 90, 140, 250, 350, and 500 {mu}m to obtain maps of the column density and temperature of 'cold' dust (near 16 K) distributed throughout the region. The large column density of cold dust associated with clouds seen in molecular emission extends continuously from the surrounding interstellar medium to project on the SNR, where the foreground component of the clouds is also detectable through optical, X-ray, and molecular extinction. At the resolution available here, there is no morphological signature to isolate any cold dust associated only with the SNR from this confusing interstellar emission. Our fit also recovers the previously detected 'hot' dust in the remnant, with characteristic temperature 100 K.

  12. AKARI/IRC 18 μm survey of warm debris disks

    NASA Astrophysics Data System (ADS)

    Fujiwara, H.; Ishihara, D.; Onaka, T.; Takita, S.; Kataza, H.; Yamashita, T.; Fukagawa, M.; Ootsubo, T.; Hirao, T.; Enya, K.; Marshall, J. P.; White, G. J.; Nakagawa, T.; Murakami, H.

    2013-02-01

    Context. Little is known about the properties of the warm (Tdust ≳ 150 K) debris disk material located close to the central star, which has a more direct link to the formation of terrestrial planets than does the low-temperature debris dust that has been detected to date. Aims: To discover new warm debris disk candidates that show large 18 μm excess and estimate the fraction of stars with excess based on the AKARI/IRC Mid-Infrared All-Sky Survey data. Methods: We searched for point sources detected in the AKARI/IRC All-Sky Survey, which show a positional match with A-M dwarf stars in the Tycho-2 Spectral Type Catalogue and exhibit excess emission at 18 μm compared to what is expected from the KS magnitude in the 2MASS catalogue. Results: We find 24 warm debris candidates including 8 new candidates among A-K stars. The apparent debris disk frequency is estimated to be 2.8 ± 0.6%. We also find that A stars and solar-type FGK stars have different characteristics of the inner component of the identified debris disk candidates. While debris disks around A stars are cooler and consistent with steady-state evolutionary model of debris disks, those around FGK stars tend to be warmer and cannot be explained by the steady-state model.

  13. X-ray and infrared diagnostics of nearby active galactic nuclei with MAXI and AKARI

    NASA Astrophysics Data System (ADS)

    Isobe, Naoki; Kawamuro, Taiki; Oyabu, Shinki; Nakagawa, Takao; Baba, Shunsuke; Yano, Kenichi; Ueda, Yoshihiro; Toba, Yoshiki

    2016-12-01

    Nearby active galactic nuclei were diagnosed in the X-ray and mid-to-far infrared wavelengths with Monitor of All-sky X-ray Image (MAXI) and the Japanese infrared observatory AKARI, respectively. One hundred of the X-ray sources listed in the second release of the MAXI all-sky X-ray source catalog are currently identified as non-blazar-type active galactic nuclei. These include 95 Seyfert galaxies and 5 quasars, and they are composed of 73 type-1 and 27 type-2 objects. The AKARI all-sky survey point source catalog was searched for their mid- and far-infrared counterparts at 9, 18, and 90 μm. As a result, 69 Seyfert galaxies in the MAXI catalog (48 type-1 and 21 type-2) were found to be detected with AKARI. The X-ray (3-4 keV and 4-10 keV) and infrared luminosities of these objects were investigated, together with their color information. Adopting the canonical photon index, Γ = 1.9, of the intrinsic X-ray spectrum of the Seyfert galaxies, the X-ray hardness ratio between the 3-4 and 4-10 keV ranges derived with MAXI was roughly converted into the absorption column density. After the X-ray luminosity was corrected for absorption from the estimated column density, the well-known X-ray-to-infrared luminosity correlation was confirmed, at least in the Compton-thin regime. In contrast, NGC 1365, the only Compton-thick object in the MAXI catalog, was found to deviate from the correlation toward a significantly lower X-ray luminosity by nearly an order of magnitude. It was verified that the relation between the X-ray hardness below 10 keV and X-ray-to-infrared color acts as an effective tool to pick up Compton-thick objects. The difference in the infrared colors between the type-1 and type-2 Seyfert galaxies and its physical implication on the classification and unification of active galactic nuclei are briefly discussed.

  14. AKARI INFRARED CAMERA SURVEY OF THE LARGE MAGELLANIC CLOUD. II. THE NEAR-INFRARED SPECTROSCOPIC CATALOG

    SciTech Connect

    Shimonishi, Takashi; Onaka, Takashi; Kato, Daisuke; Sakon, Itsuki; Ita, Yoshifusa; Kawamura, Akiko; Kaneda, Hidehiro

    2013-02-01

    We performed a near-infrared spectroscopic survey toward an area of {approx}10 deg{sup 2} of the Large Magellanic Cloud (LMC) with the infrared satellite AKARI. Observations were carried out as part of the AKARI Large-area Survey of the Large Magellanic Cloud (LSLMC). The slitless multi-object spectroscopic capability of the AKARI/IRC enabled us to obtain low-resolution (R {approx} 20) spectra in 2-5 {mu}m for a large number of point sources in the LMC. As a result of the survey, we extracted about 2000 infrared spectra of point sources. The data are organized as a near-infrared spectroscopic catalog. The catalog includes various infrared objects such as young stellar objects (YSOs), asymptotic giant branch (AGB) stars, supergiants, and so on. It is shown that 97% of the catalog sources have corresponding photometric data in the wavelength range from 1.2 to 11 {mu}m, and 67% of the sources also have photometric data up to 24 {mu}m. The catalog allows us to investigate near-infrared spectral features of sources by comparison with their infrared spectral energy distributions. In addition, it is estimated that about 10% of the catalog sources are observed at more than two different epochs. This enables us to study a spectroscopic variability of sources by using the present catalog. Initial results of source classifications for the LSLMC samples are presented. We classified 659 LSLMC spectra based on their near-infrared spectral features by visual inspection. As a result, it is shown that the present catalog includes 7 YSOs, 160 C-rich AGBs, 8 C-rich AGB candidates, 85 O-rich AGBs, 122 blue and yellow supergiants, 150 red super giants, and 128 unclassified sources. Distributions of the classified sources on the color-color and color-magnitude diagrams are discussed in the text. Continuous wavelength coverage and high spectroscopic sensitivity in 2-5 {mu}m can only be achieved by space observations. This is an unprecedented large-scale spectroscopic survey toward the

  15. AKARI observations of dust processing in merger galaxies: NGC2782 and NGC7727

    NASA Astrophysics Data System (ADS)

    Onaka, Takashi; Nakamura, Tomohiko; Sakon, Itsuki; Ohsawa, Ryou; Mori, Tamami; Wu, Ronin; Kaneda, Hidehiro

    2015-08-01

    Dust grains are the major reservoir of heavy elements and play significant roles in the thermal balance and chemistry in the interstellar medium. Where dust grains are formed and how they evolve in the ISM are one of the key issues for the understanding of the material evolution in the Universe. Although theoretical studies have been made, very little is so far known observationally about the lifecycle of dust grains in the ISM and that associated with Galactic scale events. The lifecycle of very small carbonaceous grains that contain polycyclic aromatic hydrocarbons (PAHs) or PAH-like atomic groups are of particular interest because they emit distinct band emission in the near- to mid-infrared region and they are thought to be most vulnerable to environmental conditions. PAHs may be formed in carbon-rich stars, while recent AKARI observations suggest that they may be formed by fragmentation of large carbonaceous grains in shocks in a supernova remnant or a galactic wind (Onaka et al. 2010, A&A, 514, 15; Seok et al. 2012, ApJ, 744, 160).Here we report results of AKARI observations of two mergers. NGC2782 (Arp 215) and NGC7727 (Arp 222). NGC2782 is a merger of 200Myr old. It shows a very long western tail of HI gas by a tidal interaction and the eastern tail that consists mainly of stellar components without an appreciable amount of gas and is thought to be a relic of the colliding low-mass galaxy whose gas component has been stripped off Smith 1994, AJ, 107, 1695. We found significant emission at the 7 μm band of the IRC onboard AKARI, which must come from PAH 6.2 and 7.7 μm bands, in the eastern tail. Based on dust model fitting, we found a low abundance of ~10nm size dust despite of the presence of PAHs, suggesting that PAHs may be formed from fragmentation of ~10nm carbonaceous dust grains. NGC7727 is a 1.2Gyr old merger and shows a SED similar to the NGC2782 tail in the northern tail of the merger event product, suggesting also the formation of PAHs from

  16. AKARI/AcuA PHYSICAL STUDIES OF THE CYBELE ASTEROID FAMILY

    SciTech Connect

    Kasuga, Toshihiro; Usui, Fumihiko; Hasegawa, Sunao; Kuroda, Daisuke; Ootsubo, Takafumi; Mueller, Thomas G.; Ishiguro, Masateru

    2012-06-15

    We present a study of 107 Cybele asteroids based on the archival database 'Asteroid Catalog Using AKARI (AcuA)' taken by the Infrared Astronomical Satellite. The database provides diameters D > 10 km, geometric albedos, and taxonomic information (75%) of the Cybeles. We find taxonomic diversity (mainly C-, D-, and P-type) in the population of 78 small Cybeles with diameters 10 km 80 km are mostly classified as C- or P-types (90%), with a power-law index of 2.39 {+-} 0.18. The total mass of Cybele asteroids is estimated to be {approx}10{sup -5} M{sub Earth}. We also discuss the origin and formation process of the Cybele asteroid family.

  17. ON THE RADII OF BROWN DWARFS MEASURED WITH AKARI NEAR-INFRARED SPECTROSCOPY

    SciTech Connect

    Sorahana, S.; Yamamura, I.; Murakami, H.

    2013-04-10

    We derive the radii of 16 brown dwarfs observed by AKARI using their parallaxes and the ratios of observed to model fluxes. We find that the brown dwarf radius ranges between 0.64-1.13 R{sub J} with an average radius of 0.83 R{sub J} . We find a trend in the relation between radii and T{sub eff}; the radius is at a minimum at T{sub eff} {approx} 1600 K, which corresponds to the spectral types of mid- to late-L. The result is interpreted by a combination of radius-mass and radius-age relations that are theoretically expected for brown dwarfs older than 10{sup 8} yr.

  18. INTERSTELLAR DUST PROPERTIES OF M51 FROM AKARI MID-INFRARED IMAGES

    SciTech Connect

    Egusa, Fumi; Wada, Takehiko; Arimatsu, Ko; Matsuhara, Hideo; Sakon, Itsuki; Onaka, Takashi

    2013-11-20

    Using mid-infrared (MIR) images of four photometric bands of the Infrared Camera on board the AKARI satellite, S7 (7 μm), S11 (11 μm), L15 (15 μm), and L24 (24 μm), we investigate the interstellar dust properties of the nearby pair of galaxies M51 with respect to their spiral arm structure. The arm and interarm regions are defined based on a spatially filtered stellar component model image and we measure the arm/interarm contrast for each band. The contrast is lowest in the S11 image, which we interpret as meaning that among the four AKARI MIR bands, the S11 image best correlates with the spatial distribution of dust grains including colder components. On the other hand, the L24 image, with the highest contrast, traces warmer dust heated by star forming activity. The surface brightness ratio between the bands, i.e., color, is measured over the disk of the main galaxy, M51a, at 300 pc resolution. We find that the distribution of S7/S11 is smooth and traces the global spiral arm pattern well while L15/S11 and L24/S11 peak at individual H II regions. This result indicates that the ionization state of polycyclic aromatic hydrocarbons (PAHs) is related to the spiral structure. Comparison with observational data and dust models also supports the importance of the variation in the PAH ionization state within the M51a disk. However, the mechanism driving this variation is not yet clear from the currently available datasets. Another suggestion from the comparison with the models is that the PAH fraction in the total dust mass is higher than previously estimated.

  19. Ice Mapping Observations in Galactic Star-Forming Regions: the AKARI Legacy

    NASA Astrophysics Data System (ADS)

    Fraser, Helen Jane; Suutarinnen, Aleksi; Noble, Jennifer

    2015-08-01

    It is becoming increasingly clear that explaining the small-scale distribution of many gas-phase molecules relies on our interpretation of the complex inter-connectivity between gas- and solid-phase interstellar chemistries. Inputs to proto-stellar astrochemical models are required that exploit ice compositions reflecting the historical physical conditions in pre-stellar environments when the ices first formed. Such data are required to translate the near-universe picture of ice-composition to our understanding of the role of extra-galactic ices in star-formation at higher redshifts.Here we present the first attempts at multi-object ice detections, and the subsequent ice column density mapping. The AKARI space telescope was uniquely capable of observing all the ice features between 2 and 5 microns, thereby detecting H2O, CO and CO2 ices concurrently, through their stretching vibrational features. Our group has successfully extracted an unprecedented volume of ice spectra from AKARI, including sources with not more than 2 mJy flux at 3 microns, showing:(a) H2O CO and CO2 ices on 30 lines of sight towards pre-stellar and star-forming cores, which when combined with laboratory experiments indicate how the chemistries of these three ices are interlinked (Noble et al (2013)),(b) ice maps showing the spatial distribution of water ice across 12 pre-stellar cores, in different molecular clouds (Suutarinnen et al (2015)), and the distribution of ice components within these cores on 1000 AU scales (Noble et al (2015)),(c) over 200 new detections of water ice, mostly on lines of sight towards background sources (> 145), indicating that water ice column density has a minimum value as a function of Av, but on a cloud-by-cloud basis typically correlates with Av, and dust emissivity at 250 microns (Suutarinnen et al (2015)),(d) the first detections of HDO ice towards background stars (Fraser et al (2015)).We discuss whether these results support the picture of a generic chemical

  20. AKARI INFRARED CAMERA SURVEY OF THE LARGE MAGELLANIC CLOUD. I. POINT-SOURCE CATALOG

    SciTech Connect

    Kato, Daisuke; Onaka, Takashi; Shimonishi, Takashi; Sakon, Itsuki; Ita, Yoshifusa; Tanabe, Toshihiko; Takahashi, Hidenori; Kaneda, Hidehiro; Kawamura, Akiko; Wada, Takehiko; Usui, Fumihiko; Koo, Bon-Chul; Matsuura, Mikako E-mail: onaka@astron.s.u-tokyo.ac.jp

    2012-12-01

    We present a near- to mid-infrared point-source catalog of five photometric bands at 3.2, 7, 11, 15, and 24 {mu}m for a 10 deg{sup 2} area of the Large Magellanic Cloud (LMC) obtained with the Infrared Camera on board the AKARI satellite. To cover the survey area the observations were carried out at three separate seasons from 2006 May to June, 2006 October to December, and 2007 March to July. The 10{sigma} limiting magnitudes of the present survey are 17.9, 13.8, 12.4, 9.9, and 8.6 mag at 3.2, 7, 11, 15, and 24 {mu}m, respectively. The photometric accuracy is estimated to be about 0.1 mag at 3.2 {mu}m and 0.06-0.07 mag in the other bands. The position accuracy is 0.''3 at 3.2, 7, and 11 {mu}m and 1.''0 at 15 and 24 {mu}m. The sensitivities at 3.2, 7, and 24 {mu}m are roughly comparable to those of the Spitzer SAGE LMC point-source catalog, while the AKARI catalog provides the data at 11 and 15 {mu}m, covering the mid-infrared spectral range contiguously. Two types of catalog are provided: a Catalog and an Archive. The Archive contains all the detected sources, while the Catalog only includes the sources that have a counterpart in the Spitzer SAGE point-source catalog. The Archive contains about 650,000, 140,000, 97,000, 43,000, and 52,000 sources at 3.2, 7, 11, 15, and 24 {mu}m, respectively. Based on the catalog, we discuss the luminosity functions at each band, the color-color diagram, and the color-magnitude diagram using the 3.2, 7, and 11 {mu}m band data. Stars without circumstellar envelopes, dusty C-rich and O-rich stars, young stellar objects, and background galaxies are located at distinct regions in the diagrams, suggesting that the present catalog is useful for the classification of objects toward the LMC.

  1. Bright debris disk candidates detected with the AKARI/FAR-infrared surveyor

    SciTech Connect

    Liu, Qiong; Wang, Tinggui; Jiang, Peng E-mail: twang@ustc.edu.cn

    2014-07-01

    We cross-correlate the Hipparcos main-sequence star catalog with the AKARI/FIS catalog and identify 136 stars (at >90% reliability) with far-infrared detections in at least one band. After rejecting 57 stars classified as young stellar objects, Be stars and other type stars with known dust disks or with potential contaminations, and 4 stars without infrared excess emission, we obtain a sample of 75 candidate stars with debris disks. Stars in our sample cover spectral types from B to K with most being early types. This represents a unique sample of luminous debris disks that derived uniformly from an all-sky survey with a spatial resolution factor of four better than the previous such survey by IRAS. Moreover, by collecting the infrared photometric data from other public archives, almost three-quarters of them have infrared excesses in more than one band, allowing an estimate of the dust temperatures. We fit the blackbody model to the broadband spectral energy distribution of these stars to derive the statistical distribution of the disk parameters. Four B stars with excesses in four or more bands require a double blackbody model, with the high one around 100 or 200 K and the low one around 40-50 K.

  2. WATER MASER SURVEY ON AKARI AND IRAS SOURCES: A SEARCH FOR ''LOW-VELOCITY'' WATER FOUNTAINS

    SciTech Connect

    Yung, Bosco H. K.; Nakashima, Jun-ichi; Kwok, Sun; Imai, Hiroshi; Deguchi, Shuji; Henkel, Christian

    2013-05-20

    We present the results of a 22 GHz H{sub 2}O maser survey toward a new sample of asymptotic giant branch (AGB) and post-AGB star candidates. Most of the objects are selected for the first time based on the AKARI data, which have high flux sensitivity in the mid-infrared ranges. We aim at finding H{sub 2}O maser sources in the transient phase between the AGB and post-AGB stages of evolution, where the envelopes start to develop large deviations from spherical symmetry. The observations were carried out with the Effelsberg 100 m radio telescope. Among 204 observed objects, 63 detections (36 new) were obtained. We found four objects that may be ''water fountain'' sources (IRAS 15193+3132, IRAS 18056-1514, OH 16.3-3.0, and IRAS 18455+0448). They possess an H{sub 2}O maser velocity coverage much smaller than those in other known water fountains. However, the coverage is still larger than that of the 1612 MHz OH maser. It implies that there is an outflow with a higher velocity than the envelope expansion velocity (typically {<=}25 km s{sup -1}), meeting the criterion of the water fountain class. We suggest that these candidates are possibly oxygen-rich late AGB or early post-AGB stars in a stage of evolution immediately after the spherically symmetric AGB mass loss has ceased.

  3. AKARI IRC 2.5-5 μm spectroscopy of infrared galaxies over a wide luminosity range

    SciTech Connect

    Ichikawa, Kohei; Ueda, Yoshihiro; Imanishi, Masatoshi; Nakagawa, Takao; Shirahata, Mai; Kaneda, Hidehiro; Oyabu, Shinki

    2014-10-20

    We present the result of a systematic infrared 2.5-5 μm spectroscopic study of 22 nearby infrared galaxies over a wide infrared luminosity range (10{sup 10} L {sub ☉} < L {sub IR} < 10{sup 13} L {sub ☉}) obtained from the AKARI Infrared Camera (IRC). The unique band of the AKARI IRC spectroscopy enables us to access both the 3.3 μm polycyclic aromatic hydrocarbon (PAH) emission feature from star-forming activity and the continuum of torus-dust emission heated by an active galactic nucleus (AGN). Applying our AGN diagnostics to the AKARI spectra, we discover 14 buried AGNs. The large fraction of buried AGNs suggests that AGN activity behind the dust is almost ubiquitous in ultra-/luminous infrared galaxies (U/LIRGs). We also find that both the fraction and energy contribution of buried AGNs increase with infrared luminosity from 10{sup 10} L {sub ☉} to 10{sup 13} L {sub ☉}, including normal infrared galaxies with L {sub IR} < 10{sup 11} L {sub ☉}. The energy contribution from AGNs in the total infrared luminosity is only ∼7% in LIRGs and ∼20% in ULIRGs, suggesting that the majority of the infrared luminosity originates from starburst activity. Using the PAH emission, we investigate the luminosity relation between star formation and AGNs. We find that these infrared galaxies exhibit higher star formation rates than optically selected Seyfert galaxies with the same AGN luminosities, implying that infrared galaxies could be an early evolutionary phase of AGN.

  4. AKARI observations of ice absorption bands towards edge-on YSOs

    NASA Astrophysics Data System (ADS)

    Aikawa, Y.; Kamuro, D.; Sakon, I.; Itoh, Y.; Noble, J. A.; Pontoppidan, K. M., Fraser, H. J.; Terada, H.; Tamura, M.; Kandori, R.; Kawamura, A.; Ueno, M.

    2011-05-01

    Circumstellar disks and envelopes of low-mass YSOs contain significant amounts of ice. Such icy material will evolve to volatile components of planetary systems, such as comets in our solar system. In order to investigate the composition and evolution of circumstellar ice around low-mass YSOs, we have observed ice absorption bands towards eight YSOs ranging from class 0 to class II, among which seven are associated with edge-on disks. Slit-less spectroscopic observations are performed using the grism mode of Infrared Camera (IRC) on board AKARI, which enables us to obtain full NIR spectra from 2.5 μm to 5 μm, including the CO_2 band and the blue wing of the H_2O band, which are not accessible from the ground. We developed procedures to reduce the spectra of targets with nebulosity. The spectra are fitted with polynomial baselines to derive the absorption spectra. Then we fit the molecular absorption bands with the laboratory spectra from the database, considering the instrumental line profile and the spectral resolution of the dispersion element. Towards the Class 0-I sources, absorption bands of H_2O, CO_2, CO and XCN (OCN^-) are clearly detected. Weak features of 13CO_2, HDO, the C-H band, and gaseous CO are detected as well. OCS ice absorption is tentatively detected towards IRC-L1041-2. The detected features would mostly originate in the cold envelope, while CO gas and OCN^- could originate in the region close to the protostar. Towards class II stars, H_2O ice band is detected. We also detected H_2O ice, CO_2 ice and tentative CO gas features of the foreground component of class II stars.

  5. AKARI NEAR-INFRARED SPECTROSCOPIC SURVEY FOR CO{sub 2} IN 18 COMETS

    SciTech Connect

    Ootsubo, Takafumi; Kawakita, Hideyo; Hamada, Saki; Kobayashi, Hitomi; Yamaguchi, Mitsuru; Usui, Fumihiko; Nakagawa, Takao; Ueno, Munetaka; Ishiguro, Masateru; Sekiguchi, Tomohiko; Watanabe, Jun-ichi; Sakon, Itsuki; Shimonishi, Takashi; Onaka, Takashi

    2012-06-10

    We conducted a spectroscopic survey of cometary volatiles with the Infrared Camera on board the Japanese infrared satellite AKARI in the wavelength range from 2.5 to 5 {mu}m. In our survey, 18 comets, including both the Oort cloud comets and the Jupiter-family comets, were observed in the period from 2008 June to 2010 January, most of which were observed at least twice. The prominent emission bands in the observed spectra are the fundamental vibrational bands of water (H{sub 2}O) at 2.7 {mu}m and carbon dioxide (CO{sub 2}) at 4.3 {mu}m. The fundamental vibrational band of carbon monoxide (CO) around 4.7 {mu}m and the broad emission feature, probably related to carbon-hydrogen-bearing molecules, can also be recognized around the 3.3-3.5-{mu}m region in some of the comets. With respect to H{sub 2}O, gas production rate ratios of CO{sub 2} have been derived in 17 comets, except for the comet 29P/Schwassmann-Wachmann 1. Our data set provides the largest homogeneous database of CO{sub 2}/H{sub 2}O production rate ratios in comets obtained so far. The CO{sub 2}/H{sub 2}O production rate ratios are considered to reflect the composition of cometary ice when a comet is observed at a heliocentric distance within {approx}2.5 AU, since H{sub 2}O ice fully sublimates there. The CO{sub 2}/H{sub 2}O ratio in cometary ice spans from several to {approx}30% among the comets observed at <2.5 AU (13 out of the 17 comets). Alternatively, the ratio of CO/CO{sub 2} in the comets seems to be smaller than unity based on our observations, although we only obtain upper limits for CO in most of the comets.

  6. Revised wavelength and spectral response calibrations for AKARI near-infrared grism spectroscopy: Cryogenic phase

    NASA Astrophysics Data System (ADS)

    Baba, Shunsuke; Nakagawa, Takao; Shirahata, Mai; Isobe, Naoki; Usui, Fumihiko; Ohyama, Youichi; Onaka, Takashi; Yano, Kenichi; Kochi, Chihiro

    2016-04-01

    We perform revised spectral calibrations for the AKARI near-infrared grism to correct quantitatively for the effect of the wavelength-dependent refractive index. The near-infrared grism covering the wavelength range of 2.5-5.0 μm, with a spectral resolving power of 120 at 3.6 μm, is found to be contaminated by second-order light at wavelengths longer than 4.9 μm, which is especially serious for red objects. First, we present the wavelength calibration considering the refractive index of the grism as a function of the wavelength for the first time. We find that the previous solution is positively shifted by up to 0.01 μm compared with the revised wavelengths at 2.5-5.0 μm. In addition, we demonstrate that second-order contamination occurs even with a perfect order-sorting filter owing to the wavelength dependence of the refractive index. Secondly, the spectral responses of the system from the first- and second-order light are simultaneously obtained from two types of standard objects with different colors. The response from the second-order light suggests leakage of the order-sorting filter below 2.5 μm. The relations between the output of the detector and the intensities of the first- and second-order light are formalized by a matrix equation that combines the two orders. The removal of the contaminating second-order light can be achieved by solving the matrix equation. The new calibration extends the available spectral coverage of the grism mode from 4.9 μm up to 5.0 μm. The revision can be used to study spectral features falling in these extended wavelengths, e.g., the carbon monoxide fundamental ro-vibrational absorption within nearby active galactic nuclei.

  7. AKARI observations of ice absorption bands towards edge-on young stellar objects

    NASA Astrophysics Data System (ADS)

    Aikawa, Y.; Kamuro, D.; Sakon, I.; Itoh, Y.; Terada, H.; Noble, J. A.; Pontoppidan, K. M.; Fraser, H. J.; Tamura, M.; Kandori, R.; Kawamura, A.; Ueno, M.

    2012-02-01

    Context. Circumstellar disks and envelopes of low-mass young stellar objects (YSOs) contain significant amounts of ice. Such icy material will evolve to become volatile components of planetary systems, such as comets in our solar system. Aims: To investigate the composition and evolution of circumstellar ice around low-mass young stellar objects (YSOs), we observed ice absorption bands in the near infrared (NIR) towards eight YSOs ranging from class 0 to class II, among which seven are associated with edge-on disks. Methods: We performed slit-less spectroscopic observations using the grism mode of the InfraRed Camera (IRC) on board AKARI, which enables us to obtain full NIR spectra from 2.5 μm to 5 μm, including the CO2 band and the blue wing of the H2O band, which are inaccessible from the ground. We developed procedures to carefully process the spectra of targets with nebulosity. The spectra were fitted with polynomial baselines to derive the absorption spectra. The molecular absorption bands were then fitted with the laboratory database of ice absorption bands, considering the instrumental line profile and the spectral resolution of the grism dispersion element. Results: Towards the class 0-I sources (L1527, IRC-L1041-2, and IRAS 04302), absorption bands of H2O, CO2, CO, and XCN are clearly detected. Column density ratios of CO2 ice and CO ice relative to H2O ice are 21-28% and 13-46%, respectively. If XCN is OCN-, its column density is as high as 2-6% relative to H2O ice. The HDO ice feature at 4.1 μm is tentatively detected towards the class 0-I sources and HV Tau. Non-detections of the CH-stretching mode features around 3.5 μm provide upper limits to the CH3OH abundance of 26% (L1527) and 42% (IRAS 04302) relative to H2O. We tentatively detect OCS ice absorption towards IRC-L1041-2. Towards class 0-I sources, the detected features should mostly originate in the cold envelope, while CO gas and OCN- could originate in the region close to the protostar

  8. Star Formation in Ultraluminous Infrared Galaxies Probed with AKARI Near-infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Yano, Kenichi; Nakagawa, Takao; Isobe, Naoki; Shirahata, Mai

    2016-12-01

    We conducted systematic observations of the H i Brα line (4.05 μm) and the polycyclic aromatic hydrocarbon (PAH) feature (3.3 μm) in 50 nearby (z\\lt 0.3) ultraluminous infrared galaxies (ULIRGs) with AKARI. The Brα line is predicted to be the brightest among the H i lines under conditions of high dust extinction ({A}V\\gt 15 mag). The Brα line traces ionizing photons from OB stars and so is used as an indicator of star formation on the assumption of the initial mass function. We detected the Brα line in 33 ULIRGs. The luminosity of the line ({L}{Brα }) correlates well with that of the 3.3 μm PAH emission ({L}3.3). Thus we utilize {L}3.3 as an indicator of star formation in fainter objects where the Brα line is undetected. The mean {L}{Brα }/{L}{IR} ratio in LINERs/Seyferts is significantly lower than that in H ii galaxies. This difference is reconfirmed with the {L}3.3/{L}{IR} ratio in the larger sample (46 galaxies). Using the ratios, we estimate that the contribution of starburst in LINERs/Seyferts is ∼ 67 % , and active galactic nuclei contribute the remaining ∼ 33 % . However, comparing the number of ionizing photons, {Q}{Brα }, derived from {L}{Brα } with that, Q IR, expected from the star formation rate required to explain {L}{IR}, we find that the mean {Q}{Brα }/{Q}{IR} ratio is only (55.5 ± 7.5)% even in H ii galaxies, which are thought to be energized by pure starburst. This deficit of ionizing photons traced by the Brα line is significant even taking heavy dust extinction into consideration. We propose that dust within H ii regions absorbs a significant fraction of ionizing photons.

  9. Llaki and ñakary: idioms of distress and suffering among the highland Quechua in the Peruvian Andes.

    PubMed

    Pedersen, Duncan; Kienzler, Hanna; Gamarra, Jeffrey

    2010-06-01

    This article examines some of the long-term health outcomes of extreme adversities and the ways in which social inequalities and idioms of distress are historically and socially produced in the Peruvian context. We describe how the highland Quechua of northern Ayacucho construct and experience expressions of distress and suffering such as pinsamientuwan (worrying thoughts, worries), ñakary (suffering) and llaki (sorrow, sadness), in a context of persistent social inequalities, social exclusion and a recent history of political violence. It is concluded that the multiple expressions of distress and suffering are closely related to past and current events, shaped by beliefs, core values and cultural norms and, in this process, transformed, recreated and invested with new meanings and attributions.

  10. BRIGHTNESS AND FLUCTUATION OF THE MID-INFRARED SKY FROM AKARI OBSERVATIONS TOWARD THE NORTH ECLIPTIC POLE

    SciTech Connect

    Pyo, Jeonghyun; Jeong, Woong-Seob; Matsumoto, Toshio; Matsuura, Shuji

    2012-12-01

    We present the smoothness of the mid-infrared sky from observations by the Japanese infrared astronomical satellite AKARI. AKARI monitored the north ecliptic pole (NEP) during its cold phase with nine wave bands covering from 2.4 to 24 {mu}m, out of which six mid-infrared bands were used in this study. We applied power-spectrum analysis to the images in order to search for the fluctuation of the sky brightness. Observed fluctuation is explained by fluctuation of photon noise, shot noise of faint sources, and Galactic cirrus. The fluctuations at a few arcminutes scales at short mid-infrared wavelengths (7, 9, and 11 {mu}m) are largely caused by the diffuse Galactic light of the interstellar dust cirrus. At long mid-infrared wavelengths (15, 18, and 24 {mu}m), photon noise is the dominant source of fluctuation over the scale from arcseconds to a few arcminutes. The residual fluctuation amplitude at 200'' after removing these contributions is at most 1.04 {+-} 0.23 nW m{sup -2} sr{sup -1} or 0.05% of the brightness at 24 {mu}m and at least 0.47 {+-} 0.14 nW m{sup -2} sr{sup -1} or 0.02% at 18 {mu}m. We conclude that the upper limit of the fluctuation in the zodiacal light toward the NEP is 0.03% of the sky brightness, taking 2{sigma} error into account.

  11. AKARI OBSERVATIONS OF BROWN DWARFS. III. CO, CO{sub 2}, AND CH{sub 4} FUNDAMENTAL BANDS AND PHYSICAL PARAMETERS

    SciTech Connect

    Sorahana, S.; Yamamura, I.

    2012-12-01

    We investigate variations in the strengths of three molecular bands, CH{sub 4} at 3.3 {mu}m, CO at 4.6 {mu}m, and CO{sub 2} at 4.2 {mu}m, in 16 brown dwarf spectra obtained by AKARI. Spectral features are examined along the sequence of source classes from L1 to T8. We find that the CH{sub 4} 3.3 {mu}m band is present in the spectra of brown dwarfs later than L5, and the CO 4.6 {mu}m band appears in all spectral types. The CO{sub 2} absorption band at 4.2 {mu}m is detected in late-L and T-type dwarfs. To better understand brown dwarf atmospheres, we analyze the observed spectra using the Unified Cloudy Model. The physical parameters of the AKARI sample, i.e., atmospheric effective temperature T {sub eff}, surface gravity log g, and critical temperature T {sub cr}, are derived. We also model IRTF/SpeX and UKIRT/CGS4 spectra in addition to the AKARI data in order to derive the most probable physical parameters. Correlations between the spectral type and the modeled parameters are examined. We confirm that the spectral-type sequence of late-L dwarfs is not related to T {sub eff}, but instead originates as a result of the effect of dust.

  12. ALBEDO PROPERTIES OF MAIN BELT ASTEROIDS BASED ON THE ALL-SKY SURVEY OF THE INFRARED ASTRONOMICAL SATELLITE AKARI

    SciTech Connect

    Usui, Fumihiko; Hasegawa, Sunao; Matsuhara, Hideo; Kasuga, Toshihiro; Ishiguro, Masateru; Kuroda, Daisuke; Mueller, Thomas G.; Ootsubo, Takafumi

    2013-01-01

    We present an analysis of the albedo properties of main belt asteroids (MBAs) detected by the All-Sky Survey of the infrared astronomical satellite AKARI. The characteristics of 5120 asteroids detected by the survey, including their sizes and albedos, were cataloged in the Asteroid Catalog Using AKARI (AcuA). Size and albedo measurements were based on the standard thermal model, using inputs of infrared fluxes and absolute magnitudes measured at optical wavelengths. MBAs, which account for 4722 of the 5120 AcuA asteroids, have semimajor axes of 2.06-3.27 AU, except for the near-Earth asteroids. AcuA provides a complete data set of all MBAs brighter than the absolute magnitude of H < 10.3, which corresponds to the diameter of d > 20 km. We confirmed that the albedo distribution of the MBAs is strongly bimodal as was already known from the past observations, and that the bimodal distribution occurs not only in the total population, but also within inner, middle, and outer regions of the main belt. The bimodal distribution in each group consists of low-albedo components in C-type asteroids and high-albedo components in S-type asteroids. We found that the small asteroids have much more variety in albedo than the large asteroids. In spite of the albedo transition process like space weathering, the heliocentric distribution of the mean albedo of asteroids in each taxonomic type is nearly flat. The mean albedo of the total, on the other hand, gradually decreases with an increase in semimajor axis. This can be explained by the compositional ratio of taxonomic types; that is, the proportion of dark asteroids such as C- and D-types increases, while that of bright asteroids such as S-type decreases, with increasing heliocentric distance. The heliocentric distributions of X-subclasses: E-, M-, and P-types, which can be divided based on albedo values, are also examined. P-types, which are the major component in X-types, are distributed throughout the main belt regions, and the

  13. AKARI OBSERVATIONS OF BROWN DWARFS. I. CO AND CO{sub 2} BANDS IN THE NEAR-INFRARED SPECTRA

    SciTech Connect

    Yamamura, Issei; Tsuji, Takashi; Tanabe, Toshihiko E-mail: ttsuji@ioa.s.u-tokyo.ac.j

    2010-10-10

    Near-infrared medium-resolution spectra of seven bright brown dwarfs are presented. The spectra were obtained with the Infrared Camera on board the infrared astronomical satellite AKARI, covering 2.5-5.0 {mu}m with a spectral resolution of approximately 120. The spectral types of the objects range from L5 to T8 and enable us to study the spectral evolution of brown dwarfs. The observed spectra are in general consistent with predictions from previous observations and photospheric models; spectra of L-type dwarfs are characterized by continuum opacity from dust clouds in the photosphere, while very strong molecular absorption bands dominate the spectra in T-type dwarfs. We find that the CO fundamental band around 4.6 {mu}m is clearly seen even in the T8 dwarf 2MASS J041519 - 0935, confirming the presence of a non-equilibrium chemical state in the atmosphere. We also identify the CO{sub 2} fundamental stretching-mode band at 4.2 {mu}m for the first time in the spectra of late-L- and T-type brown dwarfs. As a preliminary step towards interpretation of the data obtained by AKARI, we analyze the observed spectra by comparing with those predicted by the unified cloudy model (UCM). Although overall spectral energy distributions can be reasonably fitted with the UCM, observed CO and CO{sub 2} bands in late-L and T dwarfs are unexpectedly stronger than the model predictions assuming local thermodynamical equilibrium. We examine the vertical mixing model and find that this model explains the CO band at least partly in the T dwarfs 2MASS J041519 - 0935 and 2MASS J055919 - 1404. The CO fundamental band also shows excess absorption against the predicted one in the L9 dwarf SDSS J083008+4828. Since CO is already highly abundant in the upper photospheres of late-L dwarfs, the extra CO due to vertical mixing has little effect on the CO band strengths, and the vertical mixing model cannot be applied to this L dwarf. A more serious problem is that the significant enhancement of the

  14. Searching for the Culprit of Anomalous Microwave Emission: An AKARI PAHrange Analysis of Probable Electric Dipole Emitting Regions

    NASA Astrophysics Data System (ADS)

    Bell, A. C.; Onaka, T.; Sakon, I.; Ishihara, D.; Kaneda, H.; Lee, H. G.; Itoh, M.; Ohsawa, R.; Hammonds, M.

    In the march forward of interstellar medium inquiry, many new species of interstellar dust have been modelled and discovered. The modes by which these species interact and evolve are beginning to be understood, but in recent years a peculiar new feature has appeared in microwave surveys. Anomalous microwave emission (AME), appearing between 10 and 90Ghz, has been correlated with thermal dust emission, leading to the popular suggestion that this anomaly is electric dipole emission from spinning dust [2]. The observed frequencies suggest that spinning grains should be on the order of 10nm in size, hinting at poly-cyclic aromatic hydrocarbon molecules. We present data from AKARI/Infrared Camera [1], due to the effective PAH/Unidentified Infrared Band (UIR) coverage of its 9um survey to investigate their role within a few regions showing strong AME in the Planck low frequency data. We include the well studied Perseus and ρOphiuchi clouds . We use the IRAS/IRIS 100µm data to account for the overall dust temperature. We present our results as abundance maps for dust emitting around 9µm, and 100µm. Part of the AME in these regions may actually be attributed to thermal dust emission, or the star forming nature of these targets is masking the vibrational modes of PAHs which should be present there, suggesting further investigation for various galactic environments.

  15. A 2.5-5 μm spectroscopic study of hard X-ray selected AGNs with AKARI

    NASA Astrophysics Data System (ADS)

    Castro, A.; Miyaji, T.; Shirahata, M.; Oyabu, S.; Clark, D.; Ichikawa, K.; Imanishi, M.; Nakagawa, T.; Ueda, Y.

    2014-07-01

    We explore the relationships between the 3.3 μm polycyclic aromatic hydrocarbon (PAH) feature and active galactic nucleus (AGN) properties of a sample of 54 hard X-ray selected bright AGNs, including both Seyfert 1 and Seyfert 2 type objects, using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is selected from the 9-month Swift/BAT survey in the 14-195 keV band and all of them have measured X-ray spectra at E <~ 10 keV. These X-ray spectra provide measurements of the neutral hydrogen column density (N H) towards the AGNs. We use the 3.3 μm PAH luminosity (L 3.3μm) as a proxy for star formation activity and hard X-ray luminosity (L 14-195keV) as an indicator of the AGN activity. We searched for possible difference of star-formation activity between type 1 (un-absorbed) and type 2 (absorbed) AGNs. Our regression analysis of log L 14-195keV versus log L 3.3μm shows a positive correlation and the slope seems steeper for type 1/unobscured AGNs than that of type 2/obscured AGNs. The same trend has been found for the log (L 14-195keV/M BH) versus log (L 3.3μm/MBH) correlation. Our analysis show that the circum-nuclear star-formation is more enhanced in type 2/absorbed AGNs than type 1/un-absorbed AGNs for low X-ray luminosity/low Eddington ratio AGNs.

  16. AKARI infrared camera observations of the 3.3 μm PAH feature in Swift/BAT AGNs

    NASA Astrophysics Data System (ADS)

    Castro, Angel; Miyaji, Takamitsu; Shirahata, Mai; Ichikawa, Kohei; Oyabu, Shinki; Clark, David M.; Imanishi, Masatoshi; Nakagawa, Takao; Ueda, Yoshihiro

    2014-12-01

    We explore the relationships between the 3.3 μm polycyclic aromatic hydrocarbon (PAH) feature and active galactic nucleus (AGN) properties of a sample of 54 hard X-ray selected bright AGNs, including both Seyfert 1 and Seyfert 2 type objects, using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is selected from the nine-month Swift/BAT survey in the 14-195 keV band and all of them have measured X-ray spectra at E ≲ 10 keV. These X-ray spectra provide measurements of the neutral hydrogen column density (NH) towards the AGNs. We use the 3.3 μm PAH luminosity (L3.3μm) as a proxy for star-formation activity and hard X-ray luminosity (L14-195 keV) as an indicator of the AGN activity. We search for possible differences in star-formation activity between type 1 (unabsorbed) and type 2 (absorbed) AGNs. We have made several statistical analyses taking the upper limits of the PAH lines into account utilizing survival analysis methods. The results of our log (L14-195 keV) versus log (L3.3 μm) regression show a positive correlation and the slope for the type 1/unobscured AGNs is steeper than that of type 2/obscured AGNs at a 3 σ level. Our analysis also shows that the circumnuclear star formation is more enhanced in type 2/absorbed AGNs than type 1/unabsorbed AGNs for low X-ray luminosity/low Eddington ratio AGNs, while there is no significant dependence of star-formation activities on the AGN type in the high X-ray luminosities/Eddington ratios.

  17. DETECTION OF THE 3.3 {mu}m AROMATIC FEATURE IN THE SUPERNOVA REMNANT N49 WITH AKARI

    SciTech Connect

    Seok, Ji Yeon; Koo, Bon-Chul; Onaka, Takashi

    2012-01-10

    We present an infrared (IR) study of the supernova remnant (SNR) N49 in the Large Magellanic Cloud with the near-IR (NIR; 2.5-5 {mu}m) spectroscopic observations performed by AKARI. The observations were performed as a coarse spectral mapping to cover most of the bright region in the east, which enables us to compare the distribution of various line emissions and to examine their correlation. We detect the 3.3 {mu}m aromatic feature in the remnant, which is the first time the presence of the 3.3 {mu}m aromatic feature related to an SNR has been reported. In the line maps of the H{sub 2} 1-0 O(3), the 3.3 {mu}m feature, and the Br{alpha}, the distribution of the aromatic feature shows overall correlation with those of other emissions together with regional differences that reflect the local physical conditions. By comparing other archival imaging data at different wavelengths, the association of the aromatic emission with other ionic/molecular emissions is clarified. We examine the archival Spitzer Infrared Spectrograph data of N49 and find signatures of other polycyclic aromatic hydrocarbon (PAH) features at 6.2, 7.7, and 11.3 {mu}m corresponding to the 3.3 {mu}m aromatic feature. Based on the band ratios of the PAHs, we find that the PAHs in N49 are not only dominantly neutral, but they are also small in size. We discuss the origin of the PAH emission in N49 and conclude that the emission is either from the PAHs that have survived the shock or from the PAHs in the preshock gas that was heated by the radiative precursor.

  18. AKARI mid-infrared all-sky survey: development of the new inter-planetary dust (IPD) map and the world-first all-sky PAH map

    NASA Astrophysics Data System (ADS)

    Ishihara, D.; Kaneda, H.; Kondo, T.; Amatsutsu, T.; Nakamichi, K.; Yamagishi, M.; Oyabu, S.; Ootsubo, T.; Onaka, T.

    We are constructing accurately calibrated 9 µm and 18 µm all-sky diffuse maps from the AKARI mid-infrared all-sky survey data. These maps are heavily affected by the foreground emission of the zodiacal light, which has an intensity peak at around these wavelengths. We carefully separate the zodiacal emission component from the maps using Kelsall’s model. Through improvement of the parameters in the zodiacal light emission model, we obtained new insight on the structure and composition of the interplanetary dust in our solar system. The zodiacal light removed AKARI 9 µm map is the world’s first all-sky PAH map, that traces the emission features of Galactic polycyclic aromatic hydrocarbons (PAHs) at wavelengths of 6.2, 7.7, 8.6, and 11.3 µm. On a global scale, PAHs show good spatial correlation with tracers of general ISM such as CO, HI, and far-IR dust emissions. On a local scale, we recognize the variation of physical state and compositions of hydrocarbons reflecting the variation of the local physical environment. This PAH map will be effectively used in diagnoses of various interstellar phenomena.

  19. FAR-INFRARED IMAGING OF POST-ASYMPTOTIC GIANT BRANCH STARS AND (PROTO)-PLANETARY NEBULAE WITH THE AKARI FAR-INFRARED SURVEYOR

    SciTech Connect

    Cox, N. L. J.; Garcia-Hernandez, D. A.; Manchado, A.

    2011-04-15

    By tracing the distribution of cool dust in the extended envelopes of post-asymptotic giant branch stars and (proto)-planetary nebulae ((P)PNe), we aim to recover, or constrain, the mass-loss history experienced by these stars in their recent past. The Far-Infrared Surveyor (FIS) instrument on board the AKARI satellite was used to obtain far-infrared maps for a selected sample of post-AGB stars and (P)PNe. We derived flux densities (aperture photometry) for 13 post-AGB stars and (P)PNe at four far-infrared wavelengths (65, 90, 140, and 160 {mu}m). Radial (azimuthally averaged) profiles are used to investigate the presence of extended emission from cool dust. No (detached) extended emission is detected for any target in our sample at levels significant with respect to background and cirrus emission. Only IRAS 21046+4739 reveals tentative excess emission between 30'' and 130''. Estimates of the total dust and gas mass from the obtained maps indicate that the envelope masses of these stars should be large in order to be detected with the AKARI FIS. Imaging with higher sensitivity and higher spatial resolution is needed to detect and resolve, if present, any cool compact or extended emission associated with these evolved stars.

  20. DIFFERENCE IN THE SPATIAL DISTRIBUTION BETWEEN H{sub 2}O AND CO{sub 2} ICES IN M 82 FOUND WITH AKARI

    SciTech Connect

    Yamagishi, Mitsuyoshi; Kaneda, Hidehiro; Ishihara, Daisuke; Oyabu, Shinki; Onaka, Takashi; Shimonishi, Takashi; Suzuki, Toyoaki; Minh, Young Chol

    2013-08-20

    With AKARI, we obtain the spatially resolved near-infrared (NIR) (2.5-5.0 {mu}m) spectra for the nearby starburst galaxy M 82. These spectra clearly show absorption features due to interstellar ices. Based on the spectra, we created the column density maps of H{sub 2}O and CO{sub 2} ices. As a result, we find that the spatial distribution of H{sub 2}O ice is significantly different from that of CO{sub 2} ice; H{sub 2}O ice is widely distributed, while CO{sub 2} ice is concentrated near the galactic center. Our result reveals for the first time variations in CO{sub 2}/H{sub 2}O ice abundance ratio on a galactic scale, suggesting that an ice-forming interstellar environment changes within a galaxy. We discuss the cause of the spatial variations in the ice abundance ratio, utilizing spectral information on the hydrogen recombination Br{alpha} and Br{beta} lines and the polycyclic aromatic hydrocarbon 3.3 {mu}m emission appearing in the AKARI NIR spectra.

  1. Surface brightness correction for compact extended sources observed by the AKARI Far-Infrared Surveyor in the slow-scan mode

    NASA Astrophysics Data System (ADS)

    Ueta, Toshiya; Tomasino, Rachael L.; Takita, Satoshi; Izumiura, Hideyuki; Shirahata, Mai; Fullard, Andrew; Yamamura, Issei; Matsuura, Shuji

    2017-02-01

    We present a general surface brightness correction method for compact extended sources imaged in the slow-scan pointed observation mode of the Far-Infrared Surveyor (FIS) aboard the AKARI infrared astronomical satellite. Our method recovers correct surface brightness distribution maps by rescaling archived raw FIS maps using the surface-brightness-dependent inverse FIS response function. The flux of a target source is then automatically corrected for as the simple sum of surface brightnesses within the adopted contour encircling the perimeter of the target (i.e., contour photometry). This correction method is contrasted with the previous aperture photometry method for point sources, which directly corrects for the target flux with a flux-dependent scaling law. The new surface brightness correction scheme is applicable to objects of any shape from unresolved point sources to resolved extended objects, as long as the target is not deemed diffuse, i.e., the total extent of the target source does not exceed too much more than a single FIS scan width of 10'. The new correction method takes advantage of the well-defined shape (i.e., the scale invariance) of the point spread function, which enables us to adopt a power-law FIS response function. We analyze the point source photometric calibrator data using the FIS AKARI Slow-scan Tool and constrain the parameters of the adopted power-law FIS response function. We conclude that the photometric accuracy of the new correction method is better than 10% error based on comparisons with the expected fluxes of the photometric calibrators, and that resulting fluxes without the present correction method can lead to up to 230% overestimates or down to 50% underestimates.

  2. AKARI observations of brown dwarfs. IV. Effect of elemental abundances on near-infrared spectra between 1.0 and 5.0 μm

    SciTech Connect

    Sorahana, S.; Yamamura, I.

    2014-09-20

    The detection of the CO{sub 2} absorption band at 4.2 μm in brown dwarf spectra by AKARI has made it possible to discuss CO{sub 2} molecular abundance in brown dwarf atmospheres. In our previous studies, we found an excess in the 4.2 μm CO{sub 2} absorption band of three brown dwarf spectra, and suggested that these deviations were caused by high C and O elemental abundances in their atmospheres. To validate this hypothesis, we have constructed a set of models of brown dwarf atmospheres with various elemental abundance patterns, and we investigate the variations of the molecular composition and the thermal structure, and how they affect the near-infrared spectra between 1.0 and 5.0 μm. The 4.2 μm CO{sub 2} absorption band in some late-L and T dwarfs taken by AKARI is stronger or weaker than predicted by corresponding models with solar abundance. By comparing the CO{sub 2} band in the model spectra to the observed near-infrared spectra, we confirm possible elemental abundance variations among brown dwarfs. We find that the band strength is especially sensitive to O abundance, but C is also needed to reproduce the entire near-infrared spectra. This result indicates that both the C and O abundances should increase and decrease simultaneously for brown dwarfs. We find that a weaker CO{sub 2} absorption band in a spectrum can also be explained by a model with lower 'C and O' abundances.

  3. THE AKARI 2.5-5.0 μm SPECTRAL ATLAS OF TYPE-1 ACTIVE GALACTIC NUCLEI: BLACK HOLE MASS ESTIMATOR, LINE RATIO, AND HOT DUST TEMPERATURE

    SciTech Connect

    Kim, Dohyeong; Im, Myungshin; Kim, Ji Hoon; Jun, Hyunsung David; Lee, Seong-Kook; Woo, Jong-Hak; Lee, Hyung Mok; Lee, Myung Gyoon; Nakagawa, Takao; Matsuhara, Hideo; Wada, Takehiko; Takagi, Toshinobu; Oyabu, Shinki; Ohyama, Youichi E-mail: mim@astro.snu.ac.kr

    2015-01-01

    We present 2.5-5.0 μm spectra of 83 nearby (0.002 < z < 0.48) and bright (K < 14 mag) type-1 active galactic nuclei (AGNs) taken with the Infrared Camera on board AKARI. The 2.5-5.0 μm spectral region contains emission lines such as Brβ (2.63 μm), Brα (4.05 μm), and polycyclic aromatic hydrocarbons (3.3 μm), which can be used for studying the black hole (BH) masses and star formation activity in the host galaxies of AGNs. The spectral region also suffers less dust extinction than in the ultra violet (UV) or optical wavelengths, which may provide an unobscured view of dusty AGNs. Our sample is selected from bright quasar surveys of Palomar-Green and SNUQSO, and AGNs with reverberation-mapped BH masses from Peterson et al. Using 11 AGNs with reliable detection of Brackett lines, we derive the Brackett-line-based BH mass estimators. We also find that the observed Brackett line ratios can be explained with the commonly adopted physical conditions of the broad line region. Moreover, we fit the hot and warm dust components of the dust torus by adding photometric data of SDSS, 2MASS, WISE, and ISO to the AKARI spectra, finding hot and warm dust temperatures of ∼1100 K and ∼220 K, respectively, rather than the commonly cited hot dust temperature of 1500 K.

  4. AKARI Near-infrared Spectroscopy of the Extended Green Object G318.05+0.09: Detection of CO Fundamental Ro-vibrational Emission

    NASA Astrophysics Data System (ADS)

    Onaka, Takashi; Mori, Tamami; Sakon, Itsuki; Ardaseva, Aleksandra

    2016-10-01

    We present the results of near-infrared (2.5-5.4 μm) long-slit spectroscopy of the extended green object (EGO) G318.05+0.09 with AKARI. Two distinct sources are found in the slit. The brighter source has strong red continuum emission with H2O ice, CO2 ice, and CO gas and ice absorption features at 3.0, 4.25 μm, 4.67 μm, respectively, while the other greenish object shows peculiar emission that has double peaks at around 4.5 and 4.7 μm. The former source is located close to the ultra compact H ii region IRAS 14498-5856 and is identified as an embedded massive young stellar object (YSO). The spectrum of the latter source can be interpreted by blueshifted (-3000 ˜ -6000 km s-1) optically thin emission of the fundamental ro-vibrational transitions (v=1{--}0) of CO molecules with temperatures of 12000-3700 K without noticeable H2 and H i emission. We discuss the nature of this source in terms of outflow associated with the young stellar object and supernova ejecta associated with a supernova remnant.

  5. Systematic Variations in CO2/H2O Ice Abundance Ratios in Nearby Galaxies Found with AKARI Near-infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Yamagishi, M.; Kaneda, H.; Ishihara, D.; Oyabu, S.; Onaka, T.; Shimonishi, T.; Suzuki, T.

    2015-07-01

    We report CO2/H2O ice abundance ratios in seven nearby star-forming galaxies based on the AKARI near-infrared (2.5-5.0 μm) spectra. The CO2/H2O ice abundance ratios show clear variations between 0.05 and 0.2 with the averaged value of 0.14 ± 0.01. The previous study on M82 revealed that the CO2/H2O ice abundance ratios strongly correlate with the intensity ratios of the hydrogen recombination Brα line to the polycyclic aromatic hydrocarbon (PAH) 3.3 μm feature. In the present study, however, we find no correlation for the seven galaxies as a whole due to systematic differences in the relation between CO2/H2O ice abundance and Brα/PAH 3.3 μm intensity ratios from galaxy to galaxy. This result suggests that there is another parameter that determines the CO2/H2O ice abundance ratios in a galaxy in addition to the Brα/PAH 3.3 μm ratios. We find that the CO2/H2O ice abundance ratios positively correlate with the specific star formation rates of the galaxies. From these results, we conclude that CO2/H2O ice abundance ratios tend to be high in young star-forming galaxies.

  6. DETECTION OF PARENT H{sub 2}O AND CO{sub 2} MOLECULES IN THE 2.5-5 {mu}m SPECTRUM OF COMET C/2007 N3 (LULIN) OBSERVED WITH AKARI

    SciTech Connect

    Ootsubo, Takafumi; Usui, Fumihiko; Hasegawa, Sunao; Ueno, Munetaka; Wada, Takehiko; Matsuhara, Hideo; Nakagawa, Takao; Murakami, Hiroshi; Kawakita, Hideyo; Ishiguro, Masateru; Furusho, Reiko; Watanabe, Jun-ichi; Sekiguchi, Tomohiko; Ohyama, Youichi; Oyabu, Shinki; Onaka, Takashi

    2010-07-01

    Comet C/2007 N3 (Lulin) was observed with the Japanese infrared satellite AKARI in the near-infrared at a post-perihelion heliocentric distance of 1.7 AU. Observations were performed with the spectroscopic (2.5-5.0 {mu}m) and imaging (2.4, 3.2, and 4.1 {mu}m) modes on 2009 March 30 and 31 UT, respectively. AKARI images of the comet exhibit a sunward crescent-like shape coma and a dust tail extended toward the anti-solar direction. The 4.1 {mu}m image (CO/CO{sub 2} and dust grains) shows a distribution different from the 2.4 and 3.2 {mu}m images (H{sub 2}O and dust grains). The observed spectrum shows distinct bands at 2.66 and 4.26 {mu}m, attributed to H{sub 2}O and CO{sub 2}, respectively. This is the fifth comet in which CO{sub 2} has been directly detected in the near-infrared spectrum. In addition, CO at 4.67 {mu}m and a broad 3.2-3.6 {mu}m emission band from C-H bearing molecules were detected in the AKARI spectrum. The relative abundance ratios CO{sub 2}/H{sub 2}O and CO/H{sub 2}O derived from the molecular production rates are {approx}4%-5% and <2%, respectively. Comet Lulin belongs to the group that has relatively low abundances of CO and CO{sub 2} among all observed comets.

  7. SYSTEMATIC VARIATIONS IN CO{sub 2}/H{sub 2}O ICE ABUNDANCE RATIOS IN NEARBY GALAXIES FOUND WITH AKARI NEAR-INFRARED SPECTROSCOPY

    SciTech Connect

    Yamagishi, M.; Kaneda, H.; Ishihara, D.; Oyabu, S.; Onaka, T.; Shimonishi, T.; Suzuki, T.

    2015-07-01

    We report CO{sub 2}/H{sub 2}O ice abundance ratios in seven nearby star-forming galaxies based on the AKARI near-infrared (2.5–5.0 μm) spectra. The CO{sub 2}/H{sub 2}O ice abundance ratios show clear variations between 0.05 and 0.2 with the averaged value of 0.14 ± 0.01. The previous study on M82 revealed that the CO{sub 2}/H{sub 2}O ice abundance ratios strongly correlate with the intensity ratios of the hydrogen recombination Brα line to the polycyclic aromatic hydrocarbon (PAH) 3.3 μm feature. In the present study, however, we find no correlation for the seven galaxies as a whole due to systematic differences in the relation between CO{sub 2}/H{sub 2}O ice abundance and Brα/PAH 3.3 μm intensity ratios from galaxy to galaxy. This result suggests that there is another parameter that determines the CO{sub 2}/H{sub 2}O ice abundance ratios in a galaxy in addition to the Brα/PAH 3.3 μm ratios. We find that the CO{sub 2}/H{sub 2}O ice abundance ratios positively correlate with the specific star formation rates of the galaxies. From these results, we conclude that CO{sub 2}/H{sub 2}O ice abundance ratios tend to be high in young star-forming galaxies.

  8. THE INFRARED ARRAY CAMERA DARK FIELD: FAR-INFRARED TO X-RAY DATA

    SciTech Connect

    Krick, J. E.; Surace, J. A.; Yan, L.; Lacy, M.; Thompson, D.; Ashby, M. L. N.; Hora, J.; Gorjian, V.; Frayer, D. T.; Egami, E.

    2009-11-01

    We present 20 band photometry from the far-IR to X-ray in the Spitzer Infrared Array Camera (IRAC) dark field. The bias for the near-IR camera on Spitzer is calibrated by observing a {approx}20' diameter 'dark' field near the north ecliptic pole roughly every two-to-three weeks throughout the mission duration of Spitzer. The field is unique for its extreme depth, low background, high quality imaging, time-series information, and accompanying photometry including data taken with Akari, Palomar, MMT, KPNO, Hubble, and Chandra. This serendipitous survey contains the deepest mid-IR data taken to date. This data set is well suited for studies of intermediate-redshift galaxy clusters, high-redshift galaxies, the first generation of stars, and the lowest mass brown dwarfs, among others. This paper provides a summary of the data characteristics and catalog generation from all bands collected to date as well as a discussion of photometric redshifts and initial and expected science results and goals. To illustrate the scientific potential of this unique data set, we also present here IRAC color-color diagrams.

  9. The Spitzer-IRAC/MIPS Extragalactic Survey (SIMES) in the South Ecliptic Pole Field

    NASA Astrophysics Data System (ADS)

    Baronchelli, I.; Scarlata, C.; Rodighiero, G.; Franceschini, A.; Capak, P. L.; Mei, S.; Vaccari, M.; Marchetti, L.; Hibon, P.; Sedgwick, C.; Pearson, C.; Serjeant, S.; Menéndez-Delmestre, K.; Salvato, M.; Malkan, M.; Teplitz, H. I.; Hayes, M.; Colbert, J.; Papovich, C.; Devlin, M.; Kovacs, A.; Scott, K. S.; Surace, J.; Kirkpatrick, J. D.; Atek, H.; Urrutia, T.; Scoville, N. Z.; Takeuchi, T. T.

    2016-03-01

    We present the Spitzer-IRAC/MIPS Extragalactic survey (SIMES) in the South Ecliptic Pole field. The large area covered (7.7 deg2), together with one of the lowest Galactic cirrus emissions in the entire sky and a very extensive coverage by Spitzer, Herschel, Akari, and GALEX, make the SIMES field ideal for extragalactic studies. The elongated geometry of the SIMES area (≈4:1), allowing for significant cosmic variance reduction, further improves the quality of statistical studies in this field. Here we present the reduction and photometric measurements of the Spitzer/IRAC data. The survey reaches depths of 1.93 and 1.75 μJy (1σ) at 3.6 and 4.5 μm, respectively. We discuss the multiwavelength IRAC-based catalog, completed with optical, mid-, and far-IR observations. We detect 341,000 sources with {F}3.6μ {{m}}≥slant 3σ . Of these, 10% have an associated 24 μm counterpart, while 2.7% have an associated SPIRE source. We release the catalog through the NASA/IPAC Infrared Science Archive. Two scientific applications of these IRAC data are presented in this paper. First, we compute integral number counts at 3.6 μm. Second, we use the [3.6]-[4.5] color index to identify galaxy clusters at z > 1.3. We select 27 clusters in the full area, a result consistent with previous studies at similar depth.

  10. The Cosmic Infrared Background Experiment (CIBER): The Wide-field Imagers

    NASA Astrophysics Data System (ADS)

    Bock, J.; Sullivan, I.; Arai, T.; Battle, J.; Cooray, A.; Hristov, V.; Keating, B.; Kim, M. G.; Lam, A. C.; Lee, D. H.; Levenson, L. R.; Mason, P.; Matsumoto, T.; Matsuura, S.; Mitchell-Wynne, K.; Nam, U. W.; Renbarger, T.; Smidt, J.; Suzuki, K.; Tsumura, K.; Wada, T.; Zemcov, M.

    2013-08-01

    We have developed and characterized an imaging instrument to measure the spatial properties of the diffuse near-infrared extragalactic background light (EBL) in a search for fluctuations from z > 6 galaxies during the epoch of reionization. The instrument is part of the Cosmic Infrared Background Experiment (CIBER), designed to observe the EBL above Earth's atmosphere during a suborbital sounding rocket flight. The imaging instrument incorporates a 2° × 2° field of view to measure fluctuations over the predicted peak of the spatial power spectrum at 10 arcmin, and 7'' × 7'' pixels, to remove lower redshift galaxies to a depth sufficient to reduce the low-redshift galaxy clustering foreground below instrumental sensitivity. The imaging instrument employs two cameras with Δλ/λ ~ 0.5 bandpasses centered at 1.1 μm and 1.6 μm to spectrally discriminate reionization extragalactic background fluctuations from local foreground fluctuations. CIBER operates at wavelengths where the electromagnetic spectrum of the reionization extragalactic background is thought to peak, and complements fluctuation measurements by AKARI and Spitzer at longer wavelengths. We have characterized the instrument in the laboratory, including measurements of the sensitivity, flat-field response, stray light performance, and noise properties. Several modifications were made to the instrument following a first flight in 2009 February. The instrument performed to specifications in three subsequent flights, and the scientific data are now being analyzed.

  11. THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): THE WIDE-FIELD IMAGERS

    SciTech Connect

    Bock, J.; Battle, J.; Sullivan, I.; Arai, T.; Matsumoto, T.; Matsuura, S.; Tsumura, K.; Cooray, A.; Mitchell-Wynne, K.; Smidt, J.; Hristov, V.; Lam, A. C.; Levenson, L. R.; Mason, P.; Keating, B.; Renbarger, T.; Kim, M. G.; Lee, D. H.; Nam, U. W.; Suzuki, K.; and others

    2013-08-15

    We have developed and characterized an imaging instrument to measure the spatial properties of the diffuse near-infrared extragalactic background light (EBL) in a search for fluctuations from z > 6 galaxies during the epoch of reionization. The instrument is part of the Cosmic Infrared Background Experiment (CIBER), designed to observe the EBL above Earth's atmosphere during a suborbital sounding rocket flight. The imaging instrument incorporates a 2 Degree-Sign Multiplication-Sign 2 Degree-Sign field of view to measure fluctuations over the predicted peak of the spatial power spectrum at 10 arcmin, and 7'' Multiplication-Sign 7'' pixels, to remove lower redshift galaxies to a depth sufficient to reduce the low-redshift galaxy clustering foreground below instrumental sensitivity. The imaging instrument employs two cameras with {Delta}{lambda}/{lambda} {approx} 0.5 bandpasses centered at 1.1 {mu}m and 1.6 {mu}m to spectrally discriminate reionization extragalactic background fluctuations from local foreground fluctuations. CIBER operates at wavelengths where the electromagnetic spectrum of the reionization extragalactic background is thought to peak, and complements fluctuation measurements by AKARI and Spitzer at longer wavelengths. We have characterized the instrument in the laboratory, including measurements of the sensitivity, flat-field response, stray light performance, and noise properties. Several modifications were made to the instrument following a first flight in 2009 February. The instrument performed to specifications in three subsequent flights, and the scientific data are now being analyzed.

  12. Visual field

    MedlinePlus

    Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... Confrontation visual field exam : This is a quick and basic check of the visual field. The health care provider ...

  13. Field Trip.

    ERIC Educational Resources Information Center

    Sanders, Bill

    1993-01-01

    Reports the results of a field trip to measure the intensity of electromagnetic fields generated by electronic devices in the home, in cars, at work, outside, and in places people visit during the day. Found that a person gets more intense exposure while working at a computer than by living next to an electrical substation. (MDH)

  14. Arun field

    SciTech Connect

    Jordan, C.F. Jr.; Abdullah, M.

    1988-01-01

    The Arun field is a giant gas-condensate field operated by Mobil and Pertamina with over 20,000 acres of closure at the top of the Arun reservoir. A middle-shelf patch reef complex of early to middle Miocene age is the producing facies at the Arun field. About 1,100 ft of porous limestones, encased in shales, create a stratigraphic trap for overpressure hydrocarbons. Three main carbonate lithologies were encountered during the examination of over 4,300 ft of core; (1) a reef facies consisting of vuggy, coral encrusting, red-algal boundstones, (2) a near-reef facies consisting of foraminiferal, mixed-skeletal packstones with gravel-size coral fragments, and (3) an interreef lagoonal facies consisting of benthonic-foram packstones. Twenty-two species of corals have been identified from Arun reef facies; major reef-forming coals, listed in order of decreasing abundance, are Porites cf P. Lutes, Cyphastrea microphthalma, Astreopora myriophthalma, Styloconiella gunetheri, Porites solida, and Acropora ssp. The Arun reef is comprised of limestones (with minor amounts of dolomite). No shale beds occur in the sequence, and all carbonate facies are in communication. A pervasive microporosity, occurring throughout the Arun Limestone, results from meteoric alteration of original carbonate mud to form a microrhombic porosity that accounts for about three-fourths of the field's total porosity.

  15. Beyond Field Education: Leadership of Field Directors

    ERIC Educational Resources Information Center

    Wertheimer, Mindy R.; Sodhi, Mimi

    2014-01-01

    This article presents a conceptual model of the field director's role outside of field education, specifically in the following 3 areas of leadership: (1) curricular, (2) programmatic, and (3) institutional. A survey was conducted to explore the field director's input targeted in these areas beyond prescribed field education tasks. The…

  16. Internal split field generator

    DOEpatents

    Thundat,; George, Thomas [Knoxville, TN; Van Neste, Charles W [Kingston, TN; Vass, Arpad Alexander [Oak Ridge, TN

    2012-01-03

    A generator includes a coil of conductive material. A stationary magnetic field source applies a stationary magnetic field to the coil. An internal magnetic field source is disposed within a cavity of the coil to apply a moving magnetic field to the coil. The stationary magnetic field interacts with the moving magnetic field to generate an electrical energy in the coil.

  17. Polycyclic aromatic hydrocarbon (PAH) luminous galaxies at z ~ 1

    NASA Astrophysics Data System (ADS)

    Takagi, T.; Ohyama, Y.; Goto, T.; Matsuhara, H.; Oyabu, S.; Wada, T.; Pearson, C. P.; Lee, H. M.; Im, M.; Lee, M. G.; Shim, H.; Hanami, H.; Ishigaki, T.; Imai, K.; White, G. J.; Serjeant, S.; Malkan, M.

    2010-05-01

    Aims: The NEP-deep survey, an extragalactic AKARI survey towards the north ecliptic pole (NEP), provides a comprehensive wavelength coverage from 2 to 24 μm using all 9 photometric bands of the infrared camera (IRC). It allows us to photometrically identify galaxies whose mid-IR emission is clearly dominated by PAHs. Methods: We propose a single-colour selection method to identify such galaxies, using two mid-IR flux ratios at 11-to-7 μm and 15-to-9 μm (PAH-to-continuum flux ratio in the rest frame), which are useful for identifying starburst galaxies at z ~ 0.5 and 1, respectively. We perform a fitting of the spectral energy distributions (SEDs) from optical to mid-IR wavelengths, using an evolutionary starburst model with a proper treatment of radiative transfer (SBURT), in order to investigate their nature. Results: The SBURT model reproduces observed optical-to-mid-IR SEDs of more than a half of the PAH-selected galaxies. Based on the 8 μm luminosity, we find ultra luminous infrared galaxies (ULIRGs) among PAH-selected galaxies. Their PAH luminosity is higher than local ULIRGs with a similar luminosity, and the PAH-to-total IR luminosity ratio is consistent with that of less luminous starburst galaxies. They are a unique galaxy population at high redshifts, and we call these PAH-selected ULIRGs “PAH-luminous” galaxies. Although they are not as massive as submillimetre galaxies at z ~ 2, they have the stellar mass of > 3 × 1010 M_⊙ and therefore are moderately massive.

  18. Electrostatic Field Invisibility Cloak

    PubMed Central

    Lan, Chuwen; Yang, Yuping; Geng, Zhaoxin; Li, Bo; Zhou, Ji

    2015-01-01

    The invisibility cloak has been drawing much attention due to its new concept for manipulating many physical fields, from oscillating wave fields (electromagnetic, acoustic and elastic) to static magnetic fields, dc electric fields, and diffusive fields. Here, an electrostatic field invisibility cloak has been theoretically investigated and experimentally demonstrated to perfectly hide two dimensional objects without disturbing their external electrostatic fields. The desired cloaking effect has been achieved via both cancelling technology and transformation optics (TO). This study demonstrates a novel way for manipulating electrostatic fields, which shows promise for a wide range of potential applications. PMID:26552343

  19. External split field generator

    DOEpatents

    Thundat, Thomas George [Knoxville, TN; Van Neste, Charles W [Kingston, TN; Vass, Arpad Alexander [Oak Ridge, TN

    2012-02-21

    A generator includes a coil disposed about a core. A first stationary magnetic field source may be disposed on a first end portion of the core and a second stationary magnetic field source may be disposed on a second end portion of core. The first and second stationary magnetic field sources apply a stationary magnetic field to the coil. An external magnetic field source may be disposed outside the coil to apply a moving magnetic field to the coil. Electrical energy is generated in response to an interaction between the coil, the moving magnetic field, and the stationary magnetic field.

  20. Wake fields and wake field acceleration

    SciTech Connect

    Bane, K.L.F.; Wilson, P.B.; Weiland, T.

    1984-12-01

    In this lecture we introduce the concepts of wake fields and wake potentials, examine some basic properties of these functions, show how they can be calculated, and look briefly at a few important applications. One such application is wake field acceleration. The wake field accelerator is capable of producing the high gradients required for future very high energy e/sup +/e/sup -/ linear colliders. The principles of wake field acceleration, and a brief description of experiments in progress in this area, are presented in the concluding section. 40 references, 27 figures.

  1. Field Campaign Guidelines

    SciTech Connect

    Voyles, J. W.; Chapman, L. A.

    2015-12-01

    This document establishes a common set of guidelines for the Atmospheric Radiation Measurement (ARM) Climate Research Facility for planning, executing, and closing out field campaigns. The steps that guide individual field campaigns are described in the Field Campaign Tracking System and are specifically tailored to meet the scope of each field campaign.

  2. VizieR Online Data Catalog: Properties of asteroids in comet-like orbits (Kim+, 2014)

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Ishiguro, M.; Usui, F.

    2017-03-01

    We used infrared asteroid databases compiled from three infrared all-sky surveyors, the IRAS (Neugebauer et al. 1984ApJ...278L..83N), AKARI (Murakami et al. 2007PASJ...59S.369M), and the Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010AJ....140.1868W). Usui et al. (2014, J/PASJ/63/1117) compared these three infrared asteroid catalogs with valid sizes and albedos and merged them into a single catalog (I-A-W). They archived 138,285 asteroids with sizes and albedos, detected with either IRAS, AKARI, or WISE in I-A-W. A number of asteroids were detected by two or three satellites: 1993 asteroids by all three satellites, 2812 asteroids by AKARI and WISE, and 312 asteroids by IRAS and WISE. In such cases, Usui et al. (2014, J/PASJ/63/1117) selected data from AKARI as the highest priority, WISE as the second, and IRAS as the third priority, although there are no remarkable differences in the sizes and albedos among these catalogs. AKARI data were given highest priority because its data have less uncertainty than WISE in the sizes and albedos for the largest asteroids. We used the I-A-W catalog in the analysis of ACOs. (1 data file).

  3. Dissipative Field Theory

    SciTech Connect

    Kheirandish, F.; Amooshahi, M.

    2008-11-18

    Quantum field theory of a damped vibrating string as the simplest dissipative scalar field theory is investigated by introducing a minimal coupling method. The rate of energy flowing between the system and its environment is obtained.

  4. Planning a Field Trip

    ERIC Educational Resources Information Center

    Forecast for Home Economics, 1975

    1975-01-01

    The showroom of a button manufacturer was the site of a successful field trip for a New York City home economics class. Suggestions for field trip preparation are included as well as directions for making button jewelry. (EA)

  5. Cosmological magnetic fields

    NASA Astrophysics Data System (ADS)

    Kunze, Kerstin E.

    2013-12-01

    Magnetic fields are observed on nearly all scales in the Universe, from stars and galaxies up to galaxy clusters and even beyond. The origin of cosmic magnetic fields is still an open question, however a large class of models puts its origin in the very early Universe. A magnetic dynamo amplifying an initial seed magnetic field could explain the present day strength of the galactic magnetic field. However, it is still an open problem how and when this initial magnetic field was created. Observations of the cosmic microwave background (CMB) provide a window to the early Universe and might therefore be able to tell us whether cosmic magnetic fields are of a primordial cosmological origin and at the same time constrain its parameters. We will give an overview of the observational evidence of large-scale magnetic fields, describe generation mechanisms of primordial magnetic fields and possible imprints in the CMB.

  6. Covariant Noncommutative Field Theory

    SciTech Connect

    Estrada-Jimenez, S.; Garcia-Compean, H.; Obregon, O.; Ramirez, C.

    2008-07-02

    The covariant approach to noncommutative field and gauge theories is revisited. In the process the formalism is applied to field theories invariant under diffeomorphisms. Local differentiable forms are defined in this context. The lagrangian and hamiltonian formalism is consistently introduced.

  7. Electric Field Imaging Project

    NASA Technical Reports Server (NTRS)

    Wilcutt, Terrence; Hughitt, Brian; Burke, Eric; Generazio, Edward

    2016-01-01

    NDE historically has focused technology development in propagating wave phenomena with little attention to the field of electrostatics and emanating electric fields. This work is intended to bring electrostatic imaging to the forefront of new inspection technologies, and new technologies in general. The specific goals are to specify the electric potential and electric field including the electric field spatial components emanating from, to, and throughout volumes containing objects or in free space.

  8. Solar Wind Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Smith, E. J.

    1995-01-01

    The magnetic fields originate as coronal fields that are converted into space by the supersonic, infinitely conducting, solar wind. On average, the sun's rotation causes the field to wind up and form an Archimedes Spiral. However, the field direction changes almost continuously on a variety of scales and the irregular nature of these changes is often interpreted as evidence that the solar wind flow is turbulent.

  9. Introducing Electromagnetic Field Momentum

    ERIC Educational Resources Information Center

    Hu, Ben Yu-Kuang

    2012-01-01

    I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional…

  10. Modern Quantum Field Theory

    NASA Astrophysics Data System (ADS)

    Banks, Tom

    2008-09-01

    1. Introduction; 2. Quantum theory of free scalar fields; 3. Interacting field theory; 4. Particles of spin one, and gauge invariance; 5. Spin 1/2 particles and Fermi statistics; 6. Massive quantum electrodynamics; 7. Symmetries, Ward identities and Nambu Goldstone bosons; 8. Non-abelian gauge theory; 9. Renormalization and effective field theory; 10. Instantons and solitons; 11. Concluding remarks; Appendices; References; Index.

  11. Geological Field Trip Guidebooks

    ERIC Educational Resources Information Center

    Wallace, Harriet E.

    1978-01-01

    Geological field trip guidebooks, developed for use during a field trip or field conference, are considered ephemeral publications by their compilers and publishers. Too few copies are printed and little attention is paid to bibliographic format and information. These difficulties are discussed and recommendations are made to alleviate the…

  12. Politics of aviation fields

    NASA Technical Reports Server (NTRS)

    Vivent, Jacques

    1922-01-01

    In short, the "politics of aviation" lies in a few propositions: the need of having as large a number of fields as possible and of sufficient area; the utilization of the larger part of the existing military fields; the selection of uncultivated or unproductive fields, whenever technical conditions permit; ability to disregard (save in exceptional cases) objections of an agricultural nature.

  13. Magnetic field generator

    DOEpatents

    Krienin, Frank

    1990-01-01

    A magnetic field generating device provides a useful magnetic field within a specific retgion, while keeping nearby surrounding regions virtually field free. By placing an appropriate current density along a flux line of the source, the stray field effects of the generator may be contained. One current carrying structure may support a truncated cosine distribution, and it may be surrounded by a current structure which follows a flux line that would occur in a full coaxial double cosine distribution. Strong magnetic fields may be generated and contained using superconducting cables to approximate required current surfaces.

  14. A geomagnetic field spectrum

    NASA Technical Reports Server (NTRS)

    Langel, R. A.; Estes, R. H.

    1982-01-01

    A spherical harmonic model of the earth's internal magnetic field of degree and order 23 is derived from selected Magsat data, and its power spectrum, computed with terms developed by Mauersberger (1956) and Lowes (1974), is found to exhibit a change of a slope at n = 14 which is interpreted as an indication that the core field dominates at values lower than 13 while the crust field dominates above a value of 15. The representations of the two portions of the spectrum obtained can be used to establish order-of-magnitude inaccuracies due to both crustal fields and the inability to observe core field wavelengths beyond n = 13, at which point they are obscured by the crustal field, in core field models.

  15. Field by field hybrid upwind splitting methods

    NASA Technical Reports Server (NTRS)

    Coquel, Frederic; Liou, Meng-Sing

    1993-01-01

    A new and general approach to upwind splitting is presented. The design principle combines the robustness of flux vector splitting schemes in the capture of nonlinear waves and the accuracy of some flux difference splitting schemes in the resolution of linear waves. The new schemes are derived following a general hybridization technique performed directly at the basic level of the field by field decomposition involved in FDS methods. The scheme does not use a spatial switch to be tuned up according to the local smoothness of the approximate solution.

  16. AKARI/IRC NEAR-INFRARED SPECTRAL ATLAS OF GALACTIC PLANETARY NEBULAE

    SciTech Connect

    Ohsawa, Ryou; Onaka, Takashi; Sakon, Itsuki; Matsuura, Mikako; Kaneda, Hidehiro

    2016-04-15

    Near-infrared (2.5–5.0 μm) low-resolution (λ/Δλ ∼ 100) spectra of 72 Galactic planetary nebulae (PNe) were obtained with the Infrared Camera (IRC) in the post-helium phase. The IRC, equipped with a 1′ × 1′ window for spectroscopy of a point source, was capable of obtaining near-infrared spectra in a slit-less mode without any flux loss due to a slit. The spectra show emission features including hydrogen recombination lines and the 3.3–3.5 μm hydrocarbon features. The intensity and equivalent width of the emission features were measured by spectral fitting. We made a catalog providing unique information on the investigation of the near-infrared emission of PNe. In this paper, details of the observations and characteristics of the catalog are described.

  17. Depletion of intense fields

    NASA Astrophysics Data System (ADS)

    Bulanov, S. S.; Seipt, D.; Heinzl, T.; Marklund, M.

    2017-03-01

    The problem of backreaction of quantum processes on the properties of the background field still remains on the list of outstanding questions of high intensity particle physics. Usually, photon emission by an electron or positron, photon decay into electron-positron pairs in strong electromagnetic fields, or electron-positron pair production by such fields are described in the framework of the external field approximation. It is assumed that the external field has infinite energy and is not affected by these processes. However, the above-mentioned processes have a multi-photon nature, i.e., they occur with the absorption of a significant number of field photons. As a result, the interaction of an intense electromagnetic field with either a highly charged electron bunch or a fast growing population of electrons, positrons, and gamma photons (as in the case of an electromagnetic cascade) may lead to a depletion of the field energy, thus making the external field approximation invalid. Taking the multi-photon Compton process as an example, we estimate the threshold of depletion and find it to become significant at field strengths (a0˜103) and electron bunch charge of about tens of nC.

  18. Mapping nanoscale light fields

    NASA Astrophysics Data System (ADS)

    Rotenberg, N.; Kuipers, L.

    2014-12-01

    The control of light fields on subwavelength scales in nanophotonic structures has become ubiquitous, driven by both curiosity and a multitude of applications in fields ranging from biosensing to quantum optics. Mapping these fields in detail is crucial, as theoretical modelling is far from trivial and highly dependent on nanoscale geometry. Recent developments of nanoscale field mapping, particularly with near-field microscopy, have not only led to a vastly increased resolution, but have also resulted in increased functionality. The phase and amplitude of different vector components of both the electric and magnetic fields are now accessible, as is the ultrafast temporal or spectral evolution of propagating pulses in nanostructures. In this Review we assess the current state-of-the-art of subwavelength light mapping, highlighting the new science and nanostructures that have subsequently become accessible.

  19. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  20. Organic magnetic field sensor

    DOEpatents

    McCamey, Dane; Boehme, Christoph

    2017-01-24

    An organic, spin-dependent magnetic field sensor (10) includes an active stack (12) having an organic material with a spin-dependence. The sensor (10) also includes a back electrical contact (14) electrically coupled to a back of the active stack (12) and a front electrical contact (16) electrically coupled to a front of the active stack (12). A magnetic field generator (18) is oriented so as to provide an oscillating magnetic field which penetrates the active stack (12).

  1. Field emission electron source

    DOEpatents

    Zettl, Alexander Karlwalter; Cohen, Marvin Lou

    2000-01-01

    A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.

  2. Abandoned Texas oil fields

    SciTech Connect

    Not Available

    1980-12-01

    Data for Texas abandoned oil fields were primarily derived from two sources: (1) Texas Railroad Commission (TRRC), and (2) Dwight's ENERGYDATA. For purposes of this report, abandoned oil fields are defined as those fields that had no production during 1977. The TRRC OILMASTER computer tapes were used to identify these abandoned oil fields. The tapes also provided data on formation depth, gravity of oil production, location (both district and county), discovery date, and the cumulative production of the field since its discovery. In all, the computer tapes identified 9211 abandoned fields, most of which had less than 250,000 barrel cumulative production. This report focuses on the 676 abandoned onshore Texas oil fields that had cumulative production of over 250,000 barrels. The Dwight's ENERGYDATA computer tapes provided production histories for approximately two-thirds of the larger fields abandoned in 1966 and thereafter. Fields which ceased production prior to 1966 will show no production history nor abandonment date in this report. The Department of Energy hopes the general availability of these data will catalyze the private sector recovery of this unproduced resource.

  3. Magnetic fields from inflation?

    SciTech Connect

    Demozzi, Vittoria; Mukhanov, Viatcheslav; Rubinstein, Hector E-mail: viatcheslav.mukhanov@physik.uni-muenchen.de

    2009-08-01

    We consider the possibility of generation of the primordial magnetic field on inflation and show that the effect of the back reaction of this field can be very important. Assuming that the back reaction does not spoil inflation we find a rather strong restriction on the amplitude of the primordial field which could be generated on inflation. Namely, this amplitude recalculated to the present epoch cannot exceed 10{sup −32}G in Mpc scales. This field seems to be too small to be amplified to the observable values by a possible dynamo mechanism.

  4. Field emission chemical sensor

    DOEpatents

    Panitz, J.A.

    1983-11-22

    A field emission chemical sensor for specific detection of a chemical entity in a sample includes a closed chamber enclosing two field emission electrode sets, each field emission electrode set comprising (a) an electron emitter electrode from which field emission electrons can be emitted when an effective voltage is connected to the electrode set; and (b) a collector electrode which will capture said electrons emitted from said emitter electrode. One of the electrode sets is passive to the chemical entity and the other is active thereto and has an active emitter electrode which will bind the chemical entity when contacted therewith.

  5. Photospheric magnetic fields

    NASA Technical Reports Server (NTRS)

    Howard, R.

    1972-01-01

    Knowledge on the nature of magnetic fields on the solar surface is reviewed. At least a large part of the magnetic flux in the solar surface is confined to small bundles of lines of force within which the field strength is of the order of 500 gauss. Magnetic fields are closely associated with all types of solar activity. Magnetic flux appears at the surface at the clearly defined birth or regeneration of activity of an active region. As the region ages, the magnetic flux migrates to form large-scale patterns and the polar fields. Some manifestations of the large-scale distribution are discussed.

  6. Mercury's Magnetic Field

    NASA Astrophysics Data System (ADS)

    Johnson, C. L.

    2014-12-01

    Mercury is the only inner solar system body other than Earth to possess an active core dynamo-driven magnetic field and the only planet with a small, highly dynamic magnetosphere. Measurements made by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft have provided a wealth of data on Mercury's magnetic field environment. Mercury's weak magnetic field was discovered 40 years ago by the Mariner 10 spacecraft, but its large-scale geometry, strength and origin could not be definitively established. MESSENGER data have shown that the field is dynamo-generated and can be described as an offset axisymmetric dipole field (hereafter OAD): the magnetic equator lies ~0.2 RM (RM = 2440 km) north of the geographic equator and the dipole moment is 2.8 x1019 Am2 (~0.03% that of Earth's). The weak internal field and the high, but variable, solar wind ram pressure drive vigorous magnetospheric dynamics and result in an average distance from the planet center to the sub-solar magnetopause of only 1.42 RM. Magnetospheric models developed with MESSENGER data have allowed re-analysis of the Mariner 10 observations, establishing that there has been no measureable secular variation in the internal field over 40 years. Together with spatial power spectra for the OAD, this provides critical constraints for viable dynamo models. Time-varying magnetopause fields induce secondary core fields, the magnitudes of which confirm the core radius estimated from MESSENGER gravity and Earth-based radar data. After accounting for large-scale magnetospheric fields, residual signatures are dominated by additional external fields that are organized in the local time frame and that vary with magnetospheric activity. Birkeland currents have been identified, which likely close in the planetary interior at depths below the base of the crust. Near-periapsis magnetic field measurements at altitudes greater than 200 km have tantalizing hints of crustal fields, but crustal

  7. The North Ecliptic Pole Extragalactic Background LIght Fluctuations Survey

    NASA Astrophysics Data System (ADS)

    Bock, James; Zemcov, Michael; Cooray, Asantha; Smidt, Joseph; Serjeant, Stephen; Malkan, Matt; Matsuhara, Hideo; Matsumoto, Toshia; Matsuura, Shuji; Clements, David; Pearson, Chris; Im, Myung Shin

    2013-10-01

    We propose to image 6 deg^2 in the North Ecliptic Pole (NEP) with IRAC to determine the origin of Extragalactic Background Light (EBL) fluctuations. These Spitzer images will be combined with CIBER data at 1.1 and 1.6 um, and Akari data at 2.4, 3.2, and 4.1 um, to probe the spectrum and band-to-band correlations of the fluctuations. The fluctuations have been reported by Spitzer and Akari, and are now positively detected in new and CIBER data, but their origin is controversial. This multi-wavelength analysis will allow us to determine if EBL fluctuations arise from epoch of reionization galaxies or diffuse intra-halo light emission both by measuring their spectral energy distribution (SED) from 1.0 to 4.5 um, and by measuring the cross-correlation between different bands. The analysis uses multiple field combinations in Spitzer, CIBER and Akari data to carry out a robust measurement with multiple data combinations for internal consistency tests. In addition, the proposed survey will be used in conjunction with Akari and Herschel data in the NEP survey that has the most comprehensive multi-band infrared coverage of any degree-scale field on the sky and the best available constraints on dust phases (e.g. PAH, silicate absorption, AGN dust tori, GMCs) in galaxies. We will use this multi-wavelength coverage to cross-identify IRAC counterparts to Herschel and Akari sources and obtain SEDs of dusty, star bursting galaxies at z ~ 1 to 3 from the UV to radio, and obtain accurate PAH luminosities of Akari 7.7 um-rest detected galaxies and AGNs.

  8. Pregnant Field Students' Guilt

    ERIC Educational Resources Information Center

    Baum, Nehami

    2006-01-01

    This study examined guilt feelings among social work students who were pregnant for the first time during field work training. Semi-structured interviews were conducted either in the 9th month (n=5) or 2-12 months after delivery (n=5). Content analysis revealed 6 main triggers, illustrated by excerpts, which stimulated field students' guilt…

  9. Strong Magnetic Field Characterisation

    DTIC Science & Technology

    2012-04-01

    coils were driven by a pulsed-power system to generate the fields. All the sources were characterised through a series of measurements and modelling... generated for the coils. Options for further investigation were provided. UNCLASSIFIED UNCLASSIFIED This...investigation. The desired field strength was based on assessments [1] from preliminary magnetohydrodynamic ( MHD ) modelling and while not achievable by

  10. A Biomes Field Trip.

    ERIC Educational Resources Information Center

    Leonard, William H.; And Others

    1983-01-01

    Describes a field trip designed to give students opportunities to experience relevant data leading to concepts in biogeography. Suggests that teachers (including college instructors) adapt the areas studied and procedures used to their own locations. Includes a suggested field trip handout. (JN)

  11. Electromagnetic Field Penetration Studies

    NASA Technical Reports Server (NTRS)

    Deshpande, M.D.

    2000-01-01

    A numerical method is presented to determine electromagnetic shielding effectiveness of rectangular enclosure with apertures on its wall used for input and output connections, control panels, visual-access windows, ventilation panels, etc. Expressing EM fields in terms of cavity Green's function inside the enclosure and the free space Green's function outside the enclosure, integral equations with aperture tangential electric fields as unknown variables are obtained by enforcing the continuity of tangential electric and magnetic fields across the apertures. Using the Method of Moments, the integral equations are solved for unknown aperture fields. From these aperture fields, the EM field inside a rectangular enclosure due to external electromagnetic sources are determined. Numerical results on electric field shielding of a rectangular cavity with a thin rectangular slot obtained using the present method are compared with the results obtained using simple transmission line technique for code validation. The present technique is applied to determine field penetration inside a Boeing-757 by approximating its passenger cabin as a rectangular cavity filled with a homogeneous medium and its passenger windows by rectangular apertures. Preliminary results for, two windows, one on each side of fuselage were considered. Numerical results for Boeing-757 at frequencies 26 MHz, 171-175 MHz, and 428-432 MHz are presented.

  12. Diamond fiber field emitters

    DOEpatents

    Blanchet-Fincher, Graciela B.; Coates, Don M.; Devlin, David J.; Eaton, David F.; Silzars, Aris K.; Valone, Steven M.

    1996-01-01

    A field emission electron emitter comprising an electrode formed of at least one diamond, diamond-like carbon or glassy carbon composite fiber, said composite fiber having a non-diamond core and a diamond, diamond-like carbon or glassy carbon coating on said non-diamond core, and electronic devices employing such a field emission electron emitter.

  13. Teaching in the Field.

    ERIC Educational Resources Information Center

    Donaldson, Lou; Donaldson, George

    Beginning with a field-trip justification, this guide illuminates the problems and procedural considerations of taking school classes outside of school grounds. Major divisions of treatment are Motivating Field Work, Preparing Yourself (the teacher), Determining Purposes, Preparing for the Mechanics of the Trip, Getting Permission, Planning for…

  14. Forrest or Field?

    ERIC Educational Resources Information Center

    Mangiante, Elaine Silva

    2009-01-01

    An open field--with its wildflowers, grasses, and vole tunnels--became an instant classroom. Students' senses were awakened there, and upon entering a nearby forest, they immediately detected a difference: less light and cooler air. "Why are there no grasses in the forest? Why aren't there ferns in the field?" These and other questions emerged as…

  15. Undulator Field Integral Measurements

    SciTech Connect

    Wolf, Zachary

    2010-12-07

    The LCLS undulator field integrals must be very small so that the beam trajectory slope and offset stay within tolerance. In order to make accurate measurements of the small field integrals, a long coil will be used. This note describes the design of the coil measurement system.

  16. Tips from the Field

    ERIC Educational Resources Information Center

    Connolly, Rachel; Groome, Meghan; Sheppard, Keith; Stroud, Nick

    2006-01-01

    Field trips are opportunities to experience science in settings beyond the classroom. Much educational research has focused on effective ways of designing and planning field trips for optimal impact on the classroom and science curriculum. However, teachers are sometimes at a loss on how to design a trip that will enhance students' analytical…

  17. BOCES Field Trip Guide.

    ERIC Educational Resources Information Center

    Nassau County Board of Cooperative Educational Services, Westbury, NY.

    An effective and comprehensive guide to possible field trips for Nassau County (New York) elementary and secondary students covers places of interest in Nassau and Suffolk counties and in New York City. Recognizing that field trips can have great importance in the learning process, especially if they are directly related to the curriculum, the…

  18. Voices from the Field

    ERIC Educational Resources Information Center

    Keilty, Bonnie

    2013-01-01

    Early intervention takes its form from a variety of fields. It has its obvious roots in the fields that primarily provide early intervention services--special education, allied health, and early childhood education. Early intervention also draws from public health as a coordinated approach to addressing the biological, psychological, and social…

  19. The Coriolis field

    NASA Astrophysics Data System (ADS)

    Costa, L. Filipe; Natário, José

    2016-05-01

    We present a pedagogical discussion of the Coriolis field, emphasizing its not-so-well-understood aspects. We show that this field satisfies the field equations of the so-called Newton-Cartan theory, a generalization of Newtonian gravity that is covariant under changes of arbitrarily rotating and accelerated frames. Examples of solutions of this theory are given, including the Newtonian analogue of the Gödel universe. We discuss how to detect the Coriolis field by its effect on gyroscopes, of which the gyrocompass is an example. Finally, using a similar framework, we discuss the Coriolis field generated by mass currents in general relativity, and its measurement by the gravity probe B and LAGEOS/LARES experiments.

  20. Open field lines instabilities

    SciTech Connect

    Pozzoli, R. |

    1995-09-01

    The results of some recent theoretical papers dealing with flute-like instabilities in the scrape-off layer of a tokamak with limiter configuration, where the magnetic field intersects conducting walls, are briefly recalled. Attention is then paid to the instability driven by the electron temperature gradient across the field in conjunction with the formation of the Debye sheath at the boundary, and to the effects due to the inclination of the end walls with respect to the magnetic field. When a divertor configuration is considered, important modifications are found owing to the strong deformations of the flux tubes passing near the {ital x}-point, which contrast the onset of flute-like perturbations, and to the stochasticity of field lines that can be excited by magnetic field perturbations. {copyright} {ital 1995 American Institute of Physics.}

  1. Field resonance propulsion concept

    NASA Technical Reports Server (NTRS)

    Holt, A. C.

    1979-01-01

    A propulsion concept was developed based on a proposed resonance between coherent, pulsed electromagnetic wave forms, and gravitational wave forms (or space-time metrics). Using this concept a spacecraft propulsion system potentially capable of galactic and intergalactic travel without prohibitive travel times was designed. The propulsion system utilizes recent research associated with magnetic field line merging, hydromagnetic wave effects, free-electron lasers, laser generation of megagauss fields, and special structural and containment metals. The research required to determine potential, field resonance characteristics and to evaluate various aspects of the spacecraft propulsion design is described.

  2. Remnant field detector

    DOEpatents

    Visser, Age T.

    1988-05-03

    A method apparatus for qualitatively detecting remnant magnetic fields in matched pairs of magnet cores. Equal magnitude and oppositely oriented magnetic flux is induced in the magnet cores by oppositely wound primary windings and current source. Identically wound secondary windings generate output voltages in response to the induced flux. The output voltages generated should be of equal magnitude and opposite polarity if there is no remnant field in the cores. The output voltages will be unequal which is detected if either core has a remnant field.

  3. Gauge fields and inflation

    NASA Astrophysics Data System (ADS)

    Maleknejad, A.; Sheikh-Jabbari, M. M.; Soda, J.

    2013-07-01

    The isotropy and homogeneity of the cosmic microwave background (CMB) favors “scalar driven” early Universe inflationary models. However, gauge fields and other non-scalar fields are far more common at all energy scales, in particular at high energies seemingly relevant to inflation models. Hence, in this review we consider the role and consequences, theoretical and observational, that gauge fields can have during the inflationary era. Gauge fields may be turned on in the background during inflation, or may become relevant at the level of cosmic perturbations. There have been two main classes of models with gauge fields in the background, models which show violation of the cosmic no-hair theorem and those which lead to isotropic FLRW cosmology, respecting the cosmic no-hair theorem. Models in which gauge fields are only turned on at the cosmic perturbation level, may source primordial magnetic fields. We also review specific observational features of these models on the CMB and/or the primordial cosmic magnetic fields. Our discussions will be mainly focused on the inflation period, with only a brief discussion on the post inflationary (p)reheating era. Large field models: The initial value of the inflaton field is large, generically super-Planckian, and it rolls slowly down toward the potential minimum at smaller φ values. For instance, chaotic inflation is one of the representative models of this class. The typical potential of large-field models has a monomial form as V(φ)=V0φn. A simple analysis using the dynamical equations reveals that for number of e-folds Ne larger than 60, we require super-Planckian initial field values,5φ0>3M. For these models typically ɛ˜η˜Ne-1. Small field models: Inflaton field is initially small and slowly evolves toward the potential minimum at larger φ values. The small field models are characterized by the following potential V(φ)=V0(1-(), which corresponds to a Taylor expansion about the origin, but more realistic

  4. Remnant field detector

    DOEpatents

    Visser, Age T.

    1988-01-01

    A method apparatus for qualitatively detecting remnant magnetic fields in matched pairs of magnet cores. Equal magnitude and oppositely oriented magnetic flux is induced in the magnet cores by oppositely wound primary windings and current source. Identically wound secondary windings generate output voltages in response to the induced flux. The output voltages generated should be of equal magnitude and opposite polarity if there is no remnant field in the cores. The output voltages will be unequal which is detected if either core has a remnant field.

  5. Cosmology of bifundamental fields

    SciTech Connect

    Vachaspati, Tanmay

    2009-01-15

    If a field theory contains gauged, non-Abelian, bifundamental fields, i.e. fields that are charged under two separate non-Abelian gauge groups, the transition from a deconfined phase to a hadronic phase may be frustrated. Similar frustration may occur in non-Abelian gauge models containing matter only in higher dimensional representations, e.g. models with pure glue, or if ordinary quarks are confined by two flux tubes, as implied in the triangular configuration of baryons within QCD. In a cosmological setting, such models can lead to the formation of a web of confining electric flux tubes that can potentially have observational signatures.

  6. Kepler Field of View

    NASA Video Gallery

    The Kepler mission will be looking continuously at over 100,000 stars in one region of the sky, in the Cygnus and Lyra constellations. The field of view is extremely large for an astronomical teles...

  7. What Are Electromagnetic Fields?

    MedlinePlus

    ... will generate a single big wave; more rapid motion will generate a whole series of small waves. ... are hardly detectable. Magnetic fields arise from the motion of electric charges. The strength of the magnetic ...

  8. Baja California: Field Study

    ERIC Educational Resources Information Center

    Frey, John; Stewart, Jack

    1974-01-01

    Describes how to plan and execute an extended field trip which provides first hand observation of biological and cultural systems. Socialization of the participants was achieved through common planning and goal achievement. (BR)

  9. Field Geology/Processes

    NASA Technical Reports Server (NTRS)

    Allen, Carlton; Jakes, Petr; Jaumann, Ralf; Marshall, John; Moses, Stewart; Ryder, Graham; Saunders, Stephen; Singer, Robert

    1996-01-01

    The field geology/process group examined the basic operations of a terrestrial field geologist and the manner in which these operations could be transferred to a planetary lander. Four basic requirements for robotic field geology were determined: geologic content; surface vision; mobility; and manipulation. Geologic content requires a combination of orbital and descent imaging. Surface vision requirements include range, resolution, stereo, and multispectral imaging. The minimum mobility for useful field geology depends on the scale of orbital imagery. Manipulation requirements include exposing unweathered surfaces, screening samples, and bringing samples in contact with analytical instruments. To support these requirements, several advanced capabilities for future development are recommended. Capabilities include near-infrared reflectance spectroscopy, hyper-spectral imaging, multispectral microscopy, artificial intelligence in support of imaging, x ray diffraction, x ray fluorescence, and rock chipping.

  10. Introduction to Geomagnetic Fields

    NASA Astrophysics Data System (ADS)

    Hinze, William J.

    Coincidentally, as I sat down in late October 2003 to read and review the second edition of Wallace H. Campbell's text, Introduction to Geomagnetic Fields, we received warnings from the news media of a massive solar flare and its possible effect on power supply systems and satellite communications. News programs briefly explained the source of Sun-Earth interactions. If you are interested in learning more about the physics of the connection between sun spots and power supply systems and their impact on orbiting satellites, I urge you to become acquainted with Campbell's book. It presents an interesting and informative explanation of the geomagnetic field and its applications to a wide variety of topics, including oil exploration, climate change, and fraudulent claims of the utility of magnetic fields for alleviating human pain. Geomagnetism, the study of the nature and processes of the Earth's magnetic fields and its application to the investigation of the Earth, its processes, and history, is a mature science with a well-developed theoretical foundation and a vast array of observations. It is discussed in varied detail in Earth physics books and most entry-level geoscience texts. The latter treatments largely are driven by the need to discuss paleomagnetism as an essential tool in studying plate tectonics. A more thorough explanation of geomagnetism is needed by many interested scientists in related fields and by laypersons. This is the objective of Campbell's book. It is particularly germane in view of a broad range of geomagnetic topics that are at the forefront of today's science, including environmental magnetism, so-called ``jerks'' observed in the Earth's magnetic field, the perplexing magnetic field of Mars, improved satellite magnetic field observations, and the increasing availability of high-quality continental magnetic anomaly maps, to name only a few.

  11. Field Information Support Tool

    DTIC Science & Technology

    2010-09-01

    varying degrees of market share around the world. These operating systems include, but are not limited to: Microsoft Windows Mobile, Symbian OS...flexibility of the Android operating system , FIST can enable a much better level of collection at the forward edge of the operating environment...maximum 200 words) The Field Information Support Tool (FIST) is a field-based collection system using commercial-off-the-shelf (COTS) smartphones

  12. Magnetosheath magnetic field variability

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.

    1994-01-01

    A case study using simulations IRM and CCE observations demonstrates that transient magnetospheric events correspond to pressure pulses in the magnetosheath, inward bow shock motion, and magnetopause compression. Statistical surveys indicate that the magnetosheath magnetic field orientation rarely remains constant during periods of magnetopause and bow shock motion (both characterized by periods of 1 to 10 min). There is no tendency for bow shock motion to occur for southward interplanetary magnetic field (IMF) orientations.

  13. Collective field accelerator

    DOEpatents

    Luce, John S.

    1978-01-01

    A collective field accelerator which operates with a vacuum diode and utilizes a grooved cathode and a dielectric anode that operates with a relativistic electron beam with a .nu./.gamma. of .about. 1, and a plurality of dielectric lenses having an axial magnetic field thereabout to focus the collectively accelerated electrons and ions which are ejected from the anode. The anode and lenses operate as unoptimized r-f cavities which modulate and focus the beam.

  14. Magnetic field dosimeter development

    SciTech Connect

    Lemon, D.K.; Skorpik, J.R.; Eick, J.L.

    1980-09-01

    In recent years there has been increased concern over potential health hazards related to exposure of personnel to magnetic fields. If exposure standards are to be established, then a means for measuring magnetic field dose must be available. To meet this need, the Department of Energy has funded development of prototype dosimeters at the Battelle Pacific Northwest Laboratory. This manual reviews the principle of operation of the dosimeter and also contains step-by-step instructions for its operation.

  15. The HST Frontier Fields

    NASA Astrophysics Data System (ADS)

    Lotz, Jennifer; Mountain, M.; Grogin, N. A.; Koekemoer, A. M.; Capak, P. L.; Mack, J.; Coe, D. A.; Barker, E. A.; Adler, D. S.; Avila, R. J.; Anderson, J.; Casertano, S.; Christian, C. A.; Gonzaga, S.; Ferguson, H. C.; Fruchter, A. S.; Jenkner, H.; Jordan, I. J.; Hammer, D.; Hilbert, B.; Lawton, B. L.; Lee, J. C.; Lucas, R. A.; MacKenty, J. W.; Mutchler, M. J.; Ogaz, S.; Reid, I. N.; Royle, P.; Robberto, M.; Sembach, K.; Smith, L. J.; Sokol, J.; Surace, J. A.; Taylor, D.; Tumlinson, J.; Viana, A.; Williams, R. E.; Workman, W.

    2014-01-01

    Using Director's Discretionary observing time, HST is undertaking a revolutionary deep field observing program to peer deeper into the Universe than ever before. The Frontier Fields will combine the power of HST with the natural gravitational telescopes of high-magnification clusters of galaxies to produce the deepest observations of clusters and their lensed galaxies and the second-deepest observations of blank fields ever obtained. Up to six strong-lensing clusters (Abell 2744, MACSJ0416.1-2403, MACSJ0717.5+3745, MACSJ1149.5+2223, AbellS1063, and Abell 370) will be targeted with coordinated parallels of adjacent blank fields with ACS/WFC and WFC3/IR cameras to ~29th ABmag depths in seven bandpasses over the next three years. These observations will reveal distant galaxy populations ~10-100 times fainter than any previously observed, and improve our statistical understanding of galaxies during the epoch of reionization. Here we present Hubble Space Telescope observations of the first set of the Frontier Fields, Abell 2744, and describe the HST Frontier Fields observing strategy and schedule. All data for this observing program is nonproprietary and available immediately upon entry into the Mikulski Archive for Space Telescopes.

  16. Radial Field Piezoelectric Diaphragms

    NASA Technical Reports Server (NTRS)

    Bryant, R. G.; Effinger, R. T., IV; Copeland, B. M., Jr.

    2002-01-01

    A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes "ICE" and Interdigitated Ring Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezoceramic along the Z-axis (perpendicular to the applied electric field). Unlike other piezoelectric bender actuators, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements (several times that of the equivalent Unimorph) while maintaining a constant circumference. One of the more intriguing aspects is that the radial strain field reverses itself along the radius of the RFD while the tangential strain remains relatively constant. The result is a Z-deflection that has a conical profile. This paper covers the fabrication and characterization of the 5 cm. (2 in.) diaphragms as a function of poling field strength, ceramic thickness, electrode type and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs include the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging, and a highly repeatable fabrication process that uses commodity materials.

  17. Magnetic fields at uranus.

    PubMed

    Ness, N F; Acuña, M H; Behannon, K W; Burlaga, L F; Connerney, J E; Lepping, R P; Neubauer, F M

    1986-07-04

    The magnetic field experiment on the Voyager 2 spacecraft revealed a strong planetary magnetic field of Uranus and an associated magnetosphere and fully developed bipolar masnetic tail. The detached bow shock wave in the solar wind supersonic flow was observed upstream at 23.7 Uranus radii (1 R(U) = 25,600 km) and the magnetopause boundary at 18.0 R(U), near the planet-sun line. A miaximum magnetic field of 413 nanotesla was observed at 4.19 R(U ), just before closest approach. Initial analyses reveal that the planetary magnetic field is well represented by that of a dipole offset from the center of the planet by 0.3 R(U). The angle between Uranus' angular momentum vector and the dipole moment vector has the surprisingly large value of 60 degrees. Thus, in an astrophysical context, the field of Uranus may be described as that of an oblique rotator. The dipole moment of 0.23 gauss R(3)(U), combined with the large spatial offset, leads to minimum and maximum magnetic fields on the surface of the planet of approximately 0.1 and 1.1 gauss, respectively. The rotation period of the magnetic field and hence that of the interior of the planet is estimated to be 17.29+/- 0.10 hours; the magnetotail rotates about the planet-sun line with the same period. Thelarge offset and tilt lead to auroral zones far from the planetary rotation axis poles. The rings and the moons are embedded deep within the magnetosphere, and, because of the large dipole tilt, they will have a profound and diurnally varying influence as absorbers of the trapped radiation belt particles.

  18. The Gorgon gas field

    SciTech Connect

    Clegg, L.J.; Sayers, M.J.; Tait, A.M. )

    1990-09-01

    The Gorgon gas field was discovered by West Australian Petroleum Pty Limited (WAPET) in 1980 with the 1 Gorgon well, and appraised by 1 North Gorgon in 1982 and 1 Central Gorgon in 1983. The gas field is situated on the North West Shelf of Western Australia, 65 km northwest of WAPET's Barrow Island oil field, itself 65 km offshore. The Gorgon gas field is at the southwestern end of the Rankin Platform, which contains several giant gas fields. Water depth at the Gorgon gas field is around 250 m. The top of the Triassic Mungaroo Formation reservoir sequence is at approximately 3,500 m subsea. Individual meander-belt sandstones are up to 50 m thick and occur either interbedded with interchannel claystones or stacked to form sand bodies up to 220 m thick. The Triassic sediments form a tilted horst sealed by Cretaceous Barrow Group shales. Gross gas columns and net gas pays in the 1 Gorgon, 1 Central Gorgon, and 1 North Gorgon wells are 409 and 106 m, 441 and 45 m, and 761 and 136 m, respectively. The field is 5 km wide and at least 30 km long. Gas reserves are estimated at 232 {times} 10{sup 9} m{sup 3}, of which around 17% is carbon dioxide and nitrogen. The reservoir sandstones have porosities of 15 to 20% and permeabilities from tens to thousands of millidarcys. Individual zones have flowed gas at rates of up to 1.06 million m{sup 3}/day through a 31.75 mm choke.

  19. Field error lottery

    SciTech Connect

    Elliott, C.J.; McVey, B. ); Quimby, D.C. )

    1990-01-01

    The level of field errors in an FEL is an important determinant of its performance. We have computed 3D performance of a large laser subsystem subjected to field errors of various types. These calculations have been guided by simple models such as SWOOP. The technique of choice is utilization of the FELEX free electron laser code that now possesses extensive engineering capabilities. Modeling includes the ability to establish tolerances of various types: fast and slow scale field bowing, field error level, beam position monitor error level, gap errors, defocusing errors, energy slew, displacement and pointing errors. Many effects of these errors on relative gain and relative power extraction are displayed and are the essential elements of determining an error budget. The random errors also depend on the particular random number seed used in the calculation. The simultaneous display of the performance versus error level of cases with multiple seeds illustrates the variations attributable to stochasticity of this model. All these errors are evaluated numerically for comprehensive engineering of the system. In particular, gap errors are found to place requirements beyond mechanical tolerances of {plus minus}25{mu}m, and amelioration of these may occur by a procedure utilizing direct measurement of the magnetic fields at assembly time. 4 refs., 12 figs.

  20. Swimming in external fields

    NASA Astrophysics Data System (ADS)

    Stark, Holger

    2016-11-01

    Microswimmers move autonomously but are subject to external fields, which influence their swimming path and their collective dynamics. With three concrete examples we illustrate swimming in external fields and explain the methodology to treat it. First, an active Brownian particle shows a conventional sedimentation profile in a gravitational field but with increased sedimentation length and some polar order along the vertical. Bottom-heavy swimmers are able to invert the sedimentation profile. Second, active Brownian particles interacting by hydrodynamic flow fields in a three-dimensional harmonic trap can spontaneously break the isotropic symmetry. They develop polar order, which one can describe by mean-field theory reminiscent to Weiss theory of ferromagnetism, and thereby pump fluid. Third, a single microswimmer shows interesting non-linear dynamics in Poiseuille flow including swinging and tumbling trajectories. For pushers, hydrodynamic interactions with bounding surfaces stabilize either straight swimming against the flow or tumbling close to the channel wall, while pushers always move on a swinging trajectory with a specific amplitude as limit cycle.

  1. Research in rice fields

    USGS Publications Warehouse

    ,

    2000-01-01

    Between 1987 and 1999, 2.4-3 million acres of rice were planted annually nationwide. Rice fields are a major component of the contemporary landscapes in the Gulf Coastal Plain, the Mississippi Alluvial Valley, and Central Valley of California. In 1998, approximately 600,000 acres of rice were planted in Louisiana. In the Louisiana plant commodities report for 1998, total value for rice was over $350 million; sugarcane was the only plant commodity that exceeded this value. Louisiana has over 2,000 rice farmers supporting over 12,000 jobs in the state. Rice fields in the United States receive high use by wildlife, especially shorebirds, wading birds, and waterfowl. Waterbirds use rice fields for food, shelter, and breeding habitat.

  2. Pilot Field Test Study

    NASA Technical Reports Server (NTRS)

    Sherriff, Abigail

    2015-01-01

    The Field Test study is currently in full swing, preceded by the successful completion of the Pilot Field Test study that paved the way for collecting data on the astronauts in the medical tent in Kazakhstan. Abigail Sherriff worked alongside Logan Dobbe on one Field Test aspect to determine foot clearance over obstacles (5cm, 10cm, and 15cm) using APDM Inc. Internal Measurement Units (IMU) worn by the astronauts. They created a program to accurately calculate foot clearance using the accelerometer, magnetometer, and gyroscope data with the IMUs attached to the top of the shoes. To validate the functionality of their program, they completed a successful study on test subjects performing various tasks in an optical motion studio, considered a gold standard in biomechanics research. Future work will include further validation and expanding the program to include other analyses.

  3. Electric and magnetic fields

    NASA Technical Reports Server (NTRS)

    Kaufman, H. R.; Robinson, R. S.; Etters, R. D.

    1982-01-01

    A number of energy momentum anomalies are described that result from the use of Abraham-Lorentz electromagnetic theory. These anomalies have in common the motion of charged bodies or current carrying conductors relative to the observer. The anomalies can be avoided by using the nonflow approach, based on internal energy of the electromagnetic field. The anomalies can also be avoided by using the flow approach, if all contributions to flow work are included. The general objective of this research is a fundamental physical understanding of electric and magnetic fields which, in turn, might promote the development of new concepts in electric space propulsion. The approach taken is to investigate quantum representations of these fields.

  4. Pulsed hybrid field emitter

    SciTech Connect

    Sampayan, Stephen E.

    1998-01-01

    A hybrid emitter exploits the electric field created by a rapidly depoled ferroelectric material. Combining the emission properties of a planar thin film diamond emitter with a ferroelectric alleviates the present technological problems associated with both types of emitters and provides a robust, extremely long life, high current density cathode of the type required by emerging microwave power generation, accelerator technology and display applications. This new hybrid emitter is easy to fabricate and not susceptible to the same failures which plague microstructure field emitter technology. Local electrode geometries and electric field are determined independently from those for optimum transport and brightness preservation. Due to the large amount of surface charge created on the ferroelectric, the emitted electrons have significant energy, thus eliminating the requirement for specialized phosphors in emissive flat-panel displays.

  5. Pulsed hybrid field emitter

    DOEpatents

    Sampayan, S.E.

    1998-03-03

    A hybrid emitter exploits the electric field created by a rapidly depoled ferroelectric material. Combining the emission properties of a planar thin film diamond emitter with a ferroelectric alleviates the present technological problems associated with both types of emitters and provides a robust, extremely long life, high current density cathode of the type required by emerging microwave power generation, accelerator technology and display applications. This new hybrid emitter is easy to fabricate and not susceptible to the same failures which plague microstructure field emitter technology. Local electrode geometries and electric field are determined independently from those for optimum transport and brightness preservation. Due to the large amount of surface charge created on the ferroelectric, the emitted electrons have significant energy, thus eliminating the requirement for specialized phosphors in emissive flat-panel displays. 11 figs.

  6. Orsted Initial Field Model

    NASA Technical Reports Server (NTRS)

    Olsen, N.; Holme, R.; Hulot, G.; Sabaka, T.; Neubert, T.; Toffner-Clausen, L.; Primdahl, F.; Jorgensen, J.; Leger, J.-M.; Barraclough, D.; Smith, David E. (Technical Monitor)

    2000-01-01

    Magnetic measurements taken by the Orsted satellite during geomagnetic quiet conditions around January 1, 2000 have been used to derive a spherical harmonic model of the Earth's magnetic field for epoch 2000.0. The maximum degree and order of the model is 19 for internal, and 2 for external, source fields; however, coefficients above degree 14 may not be robust. Such detailed models exist for only one previous epoch, 1980. Achieved rms misfit is 2 nT for the scalar intensity and 4 nT for the vector components perpendicular to the magnetic field. This model is of higher detail than the IGRF 2000, which for scientific purposes related to the Orsted mission it supersedes.

  7. The ALMA Frontier Fields

    NASA Astrophysics Data System (ADS)

    Bauer, Franz E.; Gonzalez-Lopez, Jorge; Laporte, Nicolas; Muñoz Arancibia, Alejandra; Villard, Eric; Kneissl, Ruediger; Kim, Sam; ALMA Frontier Fields Team

    2017-01-01

    The Frontier Fields Legacy Program targets six strong lensing clusters with deep HST and Spitzer imaging to detect and characterize the faint background galaxy population, particularly the first galaxies at z~6-10. We initiated an ALMA survey to produce “shallow” ~2'x2' maps of the Frontier Field cluster fields at 1.1mm to study intrinsically faint dusty star-forming galaxies (DSFGs) and place constraints on the star formation from a variety of interesting extragalactic source populations. Five of the six clusters have now been completed, yielding relatively uniform maps that pinpoint cool dust emission from powerful DSFGs at z>1. I will present a census of the detected objects thus far, as well as some stacking constraints on the average emission from undetected source populations.

  8. Microbial field pilot study

    SciTech Connect

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Coates, J.D.; Chisholm, J.L.

    1993-05-01

    A multi-well microbially enhanced oil recovery field pilot has been performed in the Southeast Vassar Vertz Sand Unit in Payne County, Oklahoma. The primary emphasis of the experiment was preferential plugging of high permeability zones for the purpose of improving waterflood sweep efficiency. Studies were performed to determine reservoir chemistry, ecology, and indigenous bacteria populations. Growth experiments were used to select a nutrient system compatible with the reservoir that encouraged growth of a group of indigenous nitrate-using bacteria and inhibit growth of sulfate-reducing bacteria. A specific field pilot area behind an active line drive waterflood was selected. Surface facilities were designed and installed. Injection protocols of bulk nutrient materials were prepared to facilitate uniform distribution of nutrients within the pilot area. By the end of December, 1991, 82.5 tons (75.0 tonnes) of nutrients had been injected in the field. A tracer test identified significant heterogeneity in the SEVVSU and made it necessary to monitor additional production wells in the field. The tracer tests and changes in production behavior indicate the additional production wells monitored during the field trial were also affected. Eighty two and one half barrels (13.1 m[sup 3]) of tertiary oil have been recovered. Microbial activity has increased CO[sub 2] content as indicated by increased alkalinity. A temporary rise in sulfide concentration was experienced. These indicate an active microbial community was generated in the field by the nutrient injection. Pilot area interwell pressure interference test results showed that significant permeability reduction occurred. The interwell permeabilities in the pilot area between the injector and the three pilot production wells were made more uniform which indicates a successful preferential plugging enhanced oil recovery project.

  9. Towards graphane field emitters

    PubMed Central

    Ding, Shuyi; Li, Chi; Zhou, Yanhuai; Collins, Clare M.; Kang, Moon H.; Parmee, Richard J.; Zhang, Xiaobing; Milne, William I.; Wang, Baoping

    2015-01-01

    We report on the improved field emission performance of graphene foam (GF) following transient exposure to hydrogen plasma. The enhanced field emission mechanism associated with hydrogenation has been investigated using Fourier transform infrared spectroscopy, plasma spectrophotometry, Raman spectroscopy, and scanning electron microscopy. The observed enhanced electron emissionhas been attributed to an increase in the areal density of lattice defects and the formation of a partially hydrogenated, graphane-like material. The treated GF emitter demonstrated a much reduced macroscopic turn-on field (2.5 V μm–1), with an increased maximum current density from 0.21 mA cm–2 (pristine) to 8.27 mA cm–2 (treated). The treated GFs vertically orientated protrusions, after plasma etching, effectively increased the local electric field resulting in a 2.2-fold reduction in the turn-on electric field. The observed enhancement is further attributed to hydrogenation and the subsequent formation of a partially hydrogenated structured 2D material, which advantageously shifts the emitter work function. Alongside augmentation of the nominal crystallite size of the graphitic superstructure, surface bound species are believed to play a key role in the enhanced emission. The hydrogen plasma treatment was also noted to increase the emission spatial uniformity, with an approximate four times reduction in the per unit area variation in emission current density. Our findings suggest that plasma treatments, and particularly hydrogen and hydrogen-containing precursors, may provide an efficient, simple, and low cost means of realizing enhanced nanocarbon-based field emission devices via the engineered degradation of the nascent lattice, and adjustment of the surface work function. PMID:28066543

  10. Microbial field pilot study

    SciTech Connect

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.

    1991-12-06

    The objective of this project is to perform a microbial enhanced oil recovery field pilot test in the Southeast Vassar Vertz Sand Unit (SEVVSU) in Payne County, Oklahoma. Indigenous, anaerobic, nitrate-reducing bacteria will be stimulated to selectively plug flow paths which have been preferentially swept by a prior waterflood. This will force future flood water to invade bypassed regions of the reservoir and increase sweep efficiency. During this quarter an additional tracer study was performed in the field to determine pre-treatment flow paths and the first nutrients were injected. 2 figs.

  11. Electric field imaging

    NASA Astrophysics Data System (ADS)

    Smith, Joshua Reynolds

    The physical user interface is an increasingly significant factor limiting the effectiveness of our interactions with and through technology. This thesis introduces Electric Field Imaging, a new physical channel and inference framework for machine perception of human action. Though electric field sensing is an important sensory modality for several species of fish, it has not been seriously explored as a channel for machine perception. Technological applications of field sensing, from the Theremin to the capacitive elevator button, have been limited to simple proximity detection tasks. This thesis presents a solution to the inverse problem of inferring geometrical information about the configuration and motion of the human body from electric field measurements. It also presents simple, inexpensive hardware and signal processing techniques for makin the field measurements, and several new applications of electric field sensing. The signal processing contribution includes synchronous undersampling, a narrowband, phase sensitive detection technique that is well matched to the capabilities of contemporary microcontrollers. In hardware, the primary contributions are the School of Fish, a scalable network of microcontroller-based transceive electrodes, and the LazyFish, a small footprint integrated sensing board. Connecting n School of Fish electrodes results in an array capable of making heterodyne measurements of any or all n(n - 1) off-diagonal entries in the capacitance matrix. The LazyFish uses synchronous undersampling to provide up to 8 high signal- to-noise homodyne measurements in a very small package. The inverse electrostatics portion of the thesis presents a fast, general method for extracting geometrical information about the configuration and motion of the human body from field measurements. The method is based on the Sphere Expansion, a novel fast method for generating approximate solutions to the Laplace equation. Finally, the thesis describes a variety

  12. Pulse Field Gel Electrophoresis

    PubMed Central

    Sharma-Kuinkel, Batu K.; Rude, Thomas H.; Fowler, Vance G.

    2015-01-01

    Pulse Field Gel Electrophoresis (PFGE) is a powerful genotyping technique used for the separation of large DNA molecules (entire genomic DNA) after digesting it with unique restriction enzymes and applying to a gel matrix under the electric field that periodically changes direction. PFGE is a variation of agarose gel electrophoresis that permits analysis of bacterial DNA fragments over an order of magnitude larger than that with conventional restriction enzyme analysis. It provides a good representation of the entire bacterial chromosome in a single gel with a highly reproducible restriction profile, providing clearly distinct and well-resolved DNA fragments. PMID:25682374

  13. Field studies courses open

    NASA Astrophysics Data System (ADS)

    Fourteen month-long courses combining applied academics with training in field research methodology are being offered this summer by the School for Field Studies. The courses, held in eight countries during May, June, July, and August, provide unique opportunities for participants to work as a team under primitive conditions.‘Our courses bind together the academic challenge of the research problem, the physical challenge of the site itself, and the interpersonal challenge of the expedition team in a dynamic way so that both cognitive and affective learning are accelerated,’ according to Jim Elder, the school's director.

  14. Pulse Field Gel Electrophoresis.

    PubMed

    Sharma-Kuinkel, Batu K; Rude, Thomas H; Fowler, Vance G

    2016-01-01

    Pulse Field Gel Electrophoresis (PFGE) is a powerful genotyping technique used for the separation of large DNA molecules (entire genomic DNA) after digesting it with unique restriction enzymes and applying to a gel matrix under the electric field that periodically changes direction. PFGE is a variation of agarose gel electrophoresis that permits analysis of bacterial DNA fragments over an order of magnitude larger than that with conventional restriction enzyme analysis. It provides a good representation of the entire bacterial chromosome in a single gel with a highly reproducible restriction profile, providing clearly distinct and well-resolved DNA fragments.

  15. The Capodimonte Deep Field

    NASA Astrophysics Data System (ADS)

    2001-04-01

    A Window towards the Distant Universe Summary The Osservatorio Astronomico Capodimonte Deep Field (OACDF) is a multi-colour imaging survey project that is opening a new window towards the distant universe. It is conducted with the ESO Wide Field Imager (WFI) , a 67-million pixel advanced camera attached to the MPG/ESO 2.2-m telescope at the La Silla Observatory (Chile). As a pilot project at the Osservatorio Astronomico di Capodimonte (OAC) [1], the OACDF aims at providing a large photometric database for deep extragalactic studies, with important by-products for galactic and planetary research. Moreover, it also serves to gather experience in the proper and efficient handling of very large data sets, preparing for the arrival of the VLT Survey Telescope (VST) with the 1 x 1 degree 2 OmegaCam facility. PR Photo 15a/01 : Colour composite of the OACDF2 field . PR Photo 15b/01 : Interacting galaxies in the OACDF2 field. PR Photo 15c/01 : Spiral galaxy and nebulous object in the OACDF2 field. PR Photo 15d/01 : A galaxy cluster in the OACDF2 field. PR Photo 15e/01 : Another galaxy cluster in the OACDF2 field. PR Photo 15f/01 : An elliptical galaxy in the OACDF2 field. The Capodimonte Deep Field ESO PR Photo 15a/01 ESO PR Photo 15a/01 [Preview - JPEG: 400 x 426 pix - 73k] [Normal - JPEG: 800 x 851 pix - 736k] [Hi-Res - JPEG: 3000 x 3190 pix - 7.3M] Caption : This three-colour image of about 1/4 of the Capodimonte Deep Field (OACDF) was obtained with the Wide-Field Imager (WFI) on the MPG/ESO 2.2-m telescope at the la Silla Observatory. It covers "OACDF Subfield no. 2 (OACDF2)" with an area of about 35 x 32 arcmin 2 (about the size of the full moon), and it is one of the "deepest" wide-field images ever obtained. Technical information about this photo is available below. With the comparatively few large telescopes available in the world, it is not possible to study the Universe to its outmost limits in all directions. Instead, astronomers try to obtain the most detailed

  16. Dark-field competition

    NASA Astrophysics Data System (ADS)

    Baumbach, Christoph; mcissbc

    2014-04-01

    In reply to the physicsworld.com news story “Dark field illuminates X-ray imaging” (25 February, http://ow.ly/ulJnl), which concerns new research by Robert Cernik and colleagues (Proc. R. Soc. A 10.1098/rspa.2013.0629).

  17. [Field Learning Activities].

    ERIC Educational Resources Information Center

    Nolde Forest Environmental Education Center, Reading, PA.

    Seventy field activities, pertinent to outdoor, environmental studies, are described in this compilation. Designed for elementary and junior high school students, the activities cover many discipline areas--science, social studies, language arts, health, history, mathematics, and art--and many are multidisciplinary in use. Topics range from soil…

  18. Quantum field tomography

    NASA Astrophysics Data System (ADS)

    Steffens, A.; Riofrío, C. A.; Hübener, R.; Eisert, J.

    2014-12-01

    We introduce the concept of quantum field tomography, the efficient and reliable reconstruction of unknown quantum fields based on data of correlation functions. At the basis of the analysis is the concept of continuous matrix product states (cMPS), a complete set of variational states grasping states in one-dimensional quantum field theory. We innovate a practical method, making use of and developing tools in estimation theory used in the context of compressed sensing such as Prony methods and matrix pencils, allowing us to faithfully reconstruct quantum field states based on low-order correlation functions. In the absence of a phase reference, we highlight how specific higher order correlation functions can still be predicted. We exemplify the functioning of the approach by reconstructing randomized cMPS from their correlation data and study the robustness of the reconstruction for different noise models. Furthermore, we apply the method to data generated by simulations based on cMPS and using the time-dependent variational principle. The presented approach is expected to open up a new window into experimentally studying continuous quantum systems, such as those encountered in experiments with ultra-cold atoms on top of atom chips. By virtue of the analogy with the input-output formalism in quantum optics, it also allows for studying open quantum systems.

  19. Hubble Deep Fields

    NASA Astrophysics Data System (ADS)

    Ferguson, H.; Murdin, P.

    2000-11-01

    The Hubble Deep Fields are two small areas of the sky that were carefully selected for deep observations by the HUBBLE SPACE TELESCOPE (HST). They represent the deepest optical observations to date and reveal galaxies as faint as V=30, 4 billion times fainter than can be seen with the unaided eye....

  20. Tremont Field Site

    EPA Pesticide Factsheets

    Tremont Field Site is a 41.5-acre public park located northeast of the intersection of West 11th Street and Clark Avenue in Cleveland, Ohio. Through two deed transfers in 1948 and 1949, the City acquired the site from the United States Government.

  1. DEMONSTRATION PLAN FIELD MEASUREMENT ...

    EPA Pesticide Factsheets

    The demonstration of innovative field measurement devices for total petroleum hydrocarbons (TPH) in soil is being conducted under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation Program in June 2000 at the Navy Base Ventura County site in Port Hueneme, California. The primary purpose of the demonstration is to evaluate innovative field measurement devices for TPH in soil based on their performance and cost as compared to a conventional, off-site laboratory analytical method. The seven field measurement devices listed below will be demonstrated. CHEMetrics, Inc.'s, RemediAidTm Total Petroleum Hydrocarbon Starter Kit Wilks Enterprise, Inc.'s, Infracal' TOG/TPH Analyzer, Models CVH and HATR-T Horiba Instruments, Incorporated's, OCMA-350 Oil Content Analyzer Dexsil' Corporation's PetroFLAGTm Hydrocarbon Test Kit for Soil Environmental Systems Corporation's Synchronous Scanning Luminoscope siteLAB@ Corporation's Analytical Test Kit UVF-3 I OOA Strategic Diagnostics, Inc.'s, EnSys Petro Test System This demonstration plan describes the procedures that will be used to verify the performance and cost of each field measurement device. The plan incorporates the quality assurance and quality control elements needed to generate data of sufficient quality to document each device's performance and cost. A separate innovative technology verification report (ITVR) will be prepared for each device. The ITVRs will present the demonstratio

  2. Virtual Field Trips.

    ERIC Educational Resources Information Center

    Walter, Virginia A.

    1997-01-01

    Virtual field trips can provide experiences beyond the reach of average K-12 students. Describes multimedia products for school use: Africa Trail, Dinosaur Hunter, Louvre Museum, Magic School Bus Explores the Rainforest, and Up to the Himalayas: Kingdoms in the Clouds and provides book and Internet connections for additional learning, highlighting…

  3. Warp Field Mechanics 101

    NASA Technical Reports Server (NTRS)

    White, Harold

    2011-01-01

    This paper will begin with a short review of the Alcubierre warp drive metric and describes how the phenomenon might work based on the original paper. The canonical form of the metric was developed and published in [6] which provided key insight into the field potential and boost for the field which remedied a critical paradox in the original Alcubierre concept of operations. A modified concept of operations based on the canonical form of the metric that remedies the paradox is presented and discussed. The idea of a warp drive in higher dimensional space-time (manifold) will then be briefly considered by comparing the null-like geodesics of the Alcubierre metric to the Chung-Freese metric to illustrate the mathematical role of hyperspace coordinates. The net effect of using a warp drive technology coupled with conventional propulsion systems on an exploration mission will be discussed using the nomenclature of early mission planning. Finally, an overview of the warp field interferometer test bed being implemented in the Advanced Propulsion Physics Laboratory: Eagleworks (APPL:E) at the Johnson Space Center will be detailed. While warp field mechanics has not had a Chicago Pile moment, the tools necessary to detect a modest instance of the phenomenon are near at hand.

  4. Field-Flow Fractionation.

    ERIC Educational Resources Information Center

    Caldwell, Karin D.

    1988-01-01

    Describes a technique for separating samples that range over 15 orders of magnitude in molecular weight. Discusses theory, apparatus, and sample preparation techniques. Lists several types of field-flow fractionation (FFF) and their uses: sedimentation FFF, thermal FFF, flow FFF, electrical FFF, and steric FFF. (ML)

  5. Fields of Fuel

    ERIC Educational Resources Information Center

    Russ, Rosemary S.; Wangen, Steve; Nye, D. Leith; Shapiro, R. Benjamin; Strinz, Will; Ferris, Michael

    2015-01-01

    To help teachers engage students in discussions about sustainability, the authors designed Fields of Fuel, a multiplayer, web-based simulation game that allows players to explore the environmental and economic trade-offs of a realistic sustainable system. Computer-based simulations of real-world phenomena engage students and have been shown to…

  6. Entanglement with classical fields

    SciTech Connect

    Lee, K.F.; Thomas, J.E.

    2004-05-01

    We experimentally demonstrate a simple classical-field optical heterodyne method which employs postselection to reproduce the polarization correlations of a four-particle entangled state. We give a heuristic argument relating this method to the measurement of multiple quantum fields by correlated homodyne detection. We suggest that using multiple classical fields and postselection, one can reproduce the polarization correlations obtained in quantum experiments which employ multiple single-photon sources and linear optics to prepare multiparticle entangled states. Our experimental scheme produces four spatially separated beams which are separately detected by mixing with four independent optical local oscillators (LO) of variable polarization. Analog multiplication of the four beat signals enables projection onto a four-particle polarization-state basis. Appropriate band pass filtering is used to produce a signal proportional to the projections of the maximally entangled four-field polarization state, H{sub 1})H{sub 2})H{sub 3})H{sub 4})+V{sub 1})V{sub 2})V{sub 3})V{sub 4}), onto the product of the four LO polarizations. Since the data from multiple observers is combined prior to postselection, this method does not constitute a test of nonlocality. However, we reproduce the polarization correlations of the 32 elements in the truth table from the quantum mechanical Greenberger-Horne-Zeilinger experiments on the violation of local realism. We also demonstrate a form of classical entanglement swapping in a four-particle basis.

  7. Managing Field Evacuations.

    ERIC Educational Resources Information Center

    Satz, Jay A.; McEvoy, David; Merrill, Kurt

    In the event of a debilitating injury or illness, outdoor leaders should consider four critical phases in successfully managing backcountry field evaluations. The first phase, managing the immediate scene, involves assuring scene safety, medical care of the patient, instituting the emergency response plan, and providing for the needs of uninjured…

  8. Warp Field Mechanics 101

    NASA Astrophysics Data System (ADS)

    White, H.

    This paper will begin with a short review of the Alcubierre warp drive metric and describes how the phenomenon might work based on the original paper. The canonical form of the metric was developed and published in [6] which provided key insight into the field potential and boost for the field which remedied a critical paradox in the original Alcubierre concept of operations. A modified concept of operations based on the canonical form of the metric that remedies the paradox is presented and discussed. The idea of a warp drive in higher dimensional space-time (manifold) will then be briefly considered by comparing the null-like geodesics of the Alcubierre metric to the Chung-Freese metric to illustrate the mathematical role of hyperspace coordinates. The net effect of using a warp drive "technology" coupled with conventional propulsion systems on an exploration mission will be discussed using the nomenclature of early mission planning. Finally, an overview of the warp field interferometer test bed being implemented in the Advanced Propulsion Physics Laboratory: Eagleworks (APPL:E) at the Johnson Space Center will be detailed. While warp field mechanics has not had a "Chicago Pile" moment, the tools necessary to detect a modest instance of the phenomenon are near at hand.

  9. Holden Crater Dune Field

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

    A common location for dune fields on Mars is in the basin of large craters. This dune field is located in Holden Crater at 25 degrees South atitude.

    Image information: VIS instrument. Latitude -25.5, Longitude 326.8 East (33.2 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  10. Vector fields in cosmology

    NASA Astrophysics Data System (ADS)

    Davydov, E. A.

    2012-06-01

    Vector fields can arise in the cosmological context in different ways, and we discuss both abelian and nonabelian sector. In the abelian sector vector fields of the geometrical origin (from dimensional reduction and Einstein-Eddington modification of gravity) can provide a very non-trivial dynamics, which can be expressed in terms of the effective dilaton-scalar gravity with the specific potential. In the non-abelian sector we investigate the Yang-Mills SU(2) theory which admits isotropic and homogeneous configuration. Provided the non-linear dependence of the lagrangian on the invariant FμνF~μν, one can obtain the inflationary regime with the exponential growth of the scale factor. The effective amplitudes of the `electric' and `magnetic' components behave like slowly varying scalars at this regime, what allows the consideration of some realistic models with non-linear terms in the Yang-Mills lagrangian.

  11. Bigfoot Field Manual

    NASA Astrophysics Data System (ADS)

    Campbell, J. L.; Burrows, S.; Gower, S. T.; Cohen, W. B.

    1999-09-01

    The BigFoot Project is funded by the Earth Science Enterprise to collect and organize data to be used in the EOS Validation Program. The data collected by the BigFoot Project are unique in being ground-based observations coincident with satellite overpasses. In addition to collecting data, the BigFoot project will develop and test new algorithms for scaling point measurements to the same spatial scales as the EOS satellite products. This BigFoot Field Manual Mill be used to achieve completeness and consistency of data collected at four initial BigFoot sites and at future sites that may collect similar validation data. Therefore, validation datasets submitted to the ORNL DAAC that have been compiled in a manner consistent with the field manual will be especially valuable in the validation program.

  12. Wake field acceleration experiments

    SciTech Connect

    Simpson, J.D.

    1988-01-01

    Where and how will wake field acceleration devices find use for other than, possibly, accelerators for high energy physics. I don't know that this can be responsibly answered at this time. What I can do is describe some recent results from an ongoing experimental program at Argonne which support the idea that wake field techniques and devices are potentially important for future accelerators. Perhaps this will spawn expanded interest and even new ideas for the use of this new technology. The Argonne program, and in particular the Advanced Accelerator Test Facility (AATF), has been reported in several fairly recent papers and reports. But because this is a substantially new audience for the subject, I will include a brief review of the program and the facility before describing experiments. 10 refs., 7 figs.

  13. (abstract) Venus Gravity Field

    NASA Technical Reports Server (NTRS)

    Konopliv, A. S.; Sjogren, W. L.

    1995-01-01

    A global gravity field model of Venus to degree and order 75 (5772 spherical harmonic coefficients) has been estimated from Doppler radio tracking of the orbiting spacecraft Pioneer Venus Orbiter (1979-1992) and Magellan (1990-1994). After the successful aerobraking of Magellan, a near circular polar orbit was attained and relatively uniform gravity field resolution (approximately 200 km) was obtained with formal uncertainties of a few milligals. Detailed gravity for several highland features are displayed as gravity contours overlaying colored topography. The positive correlation of typography with gravity is very high being unlike that of the Earth, Moon, and Mars. The amplitudes are Earth-like, but have significantly different gravity-topography ratios for different features. Global gravity, geoid, and isostatic anomaly maps as well as the admittance function are displayed.

  14. Magnetic fields and cancer

    SciTech Connect

    Jones, T.L.

    1993-10-01

    This letter is a response to an article by Savitz and Kaune, EHP 101:76-80. W-L wire code was applied to data from a 1988 Denver study, and an association was reported between high W-L wire code and childhood cancer. This author discusses several studies and provides explanations which weakens the argument that classification error resulted in an appreciable reduction in the association between W-L high wire code and childhood cancer. In conclusion, the fact that new wire code is only weakly correlated with magnetic field measurements (in the same manner as the original W-L wire code) suggests that the newly reported stronger association with childhood cancer is likely due to factors other than magnetic fields. Differential residential mobility and differential residential age are two possible explanations and are suggestive that the reported association may be false.

  15. Graphene field emission devices

    SciTech Connect

    Kumar, S. Raghavan, S.; Duesberg, G. S.; Pratap, R.

    2014-09-08

    Graphene field emission devices are fabricated using a scalable process. The field enhancement factors, determined from the Fowler-Nordheim plots, are within few hundreds and match the theoretical predictions. The devices show high emission current density of ∼10 nA μm{sup −1} at modest voltages of tens of volts. The emission is stable with time and repeatable over long term, whereas the noise in the emission current is comparable to that from individual carbon nanotubes emitting under similar conditions. We demonstrate a power law dependence of emission current on pressure which can be utilized for sensing. The excellent characteristics and relative ease of making the devices promise their great potential for sensing and electronic applications.

  16. Habituating field scientists.

    PubMed

    Alcayna-Stevens, Lys

    2016-12-01

    This article explores the sensory dimensions of scientific field research in the only region in the world where free-ranging bonobos ( Pan paniscus) can be studied in their natural environment; the equatorial rainforest of the Democratic Republic of Congo. If, as sensory anthropologists have argued, the senses are developed, grown and honed in a given cultural and environmental milieu, how is it that field scientists come to dwell among familiarity in a world which is, at first, unfamiliar? This article builds upon previous anthropological and philosophical engagements with habituation that have critically examined primatologists' attempts to become 'neutral objects in the environment' in order to habituate wild apes to their presence. It does so by tracing the somatic modes of attention developed by European and North American researchers as they follow bonobos in these forests. The argument is that as environments, beings and their elements become familiar, they do not become 'neutral', but rather, suffused with meaning.

  17. Field reparametrization in SMEFT

    NASA Astrophysics Data System (ADS)

    Passarino, Giampiero

    2017-01-01

    Debate topic for effective field theory (EFT) is the choice of a "basis" for dim= 6 operators. Clearly all bases are equivalent as long as they are a "basis", containing a minimal set of operators after the use of equations of motion and respecting the SU(3)× SU(2)× U(1) gauge invariance. From a more formal point of view a basis is characterized by its closure with respect to renormalization. Equivalence of bases should always be understood as a statement for the S-matrix and not for the Lagrangian, as dictated by the equivalence theorem. Any phenomenological approach that misses one of these ingredients is still acceptable for a preliminar analysis, as long as it does not pretend to be an EFT. Here we revisit the equivalence theorem and its consequences for EFT when two sets of higher-dimensional operators are connected by a set of non-linear, non-invariant, field reparametrizations.

  18. High field pulsed microwiggler

    SciTech Connect

    Warren, R.W.

    1990-12-31

    This paper describes a microwiggler assembly which produces large magnetic fields for oscillating charged particle beams, particularly electron beams for free electron laser (FEL) application. A tube of electrically conductive material is formed with radial slots axially spaced at the period of the electron beam. The slots have alternate 180{degrees} relationships and are formed to a maximum depth of 0.6 to 0.7 times the tube circumference. An optimum slot depth is selected eliminate magnetic quadrupole fields within the microwiggler as determined from a conventional pulsed wire technique. Suitable slot configurations include single slits, double slits, triple slits, and elliptical slots. An axial electron beam direction is maintained by experimentally placing end slits adjacent entrance and exit portions of the assembly, where the end slit depth is determined by use of the pulsed wire technique outside the tube.

  19. High field pulsed microwiggler

    SciTech Connect

    Warren, R.W.

    1990-01-01

    This paper describes a microwiggler assembly which produces large magnetic fields for oscillating charged particle beams, particularly electron beams for free electron laser (FEL) application. A tube of electrically conductive material is formed with radial slots axially spaced at the period of the electron beam. The slots have alternate 180{degrees} relationships and are formed to a maximum depth of 0.6 to 0.7 times the tube circumference. An optimum slot depth is selected eliminate magnetic quadrupole fields within the microwiggler as determined from a conventional pulsed wire technique. Suitable slot configurations include single slits, double slits, triple slits, and elliptical slots. An axial electron beam direction is maintained by experimentally placing end slits adjacent entrance and exit portions of the assembly, where the end slit depth is determined by use of the pulsed wire technique outside the tube.

  20. The interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Davis, L., Jr.

    1972-01-01

    Large-scale properties of the interplanetary magnetic field as determined by the solar wind velocity structure are examined. The various ways in which magnetic fields affect phenomena in the solar wind are summarized. The dominant role of high and low velocity solar wind streams that persist, with fluctuations and evolution, for weeks or months is emphasized. It is suggested that for most purposes the sector structure is better identified with the stream structure than with the magnetic polarity and that the polarity does not necessarily change from one velocity sector to the next. Several mechanisms that might produce the stream structure are considered. The interaction of the high and low velocity streams is analyzed in a model that is steady state when viewed in a frame that corotates with the sun.

  1. Conformal scalar field wormholes

    NASA Technical Reports Server (NTRS)

    Halliwell, Jonathan J.; Laflamme, Raymond

    1989-01-01

    The Euclidian Einstein equations with a cosmological constant and a conformally coupled scalar field are solved, taking the metric to be of the Robertson-Walker type. In the case Lambda = 0, solutions are found which represent a wormhole connecting two asymptotically flat Euclidian regions. In the case Lambda greater than 0, the solutions represent tunneling from a small Tolman-like universe to a large Robertson-Walker universe.

  2. Proca and electromagnetic fields

    SciTech Connect

    Hillion, P.; Quinnerz, S.

    1986-07-01

    In the framework of the proper orthochronous Lorentz group, the old connection is revived between the electromagnetic field characterized by a self-dual tensor and a traceless second-rank spinor obeying the Proca equation. The relationship between this spinor and the Hertz potential also considered as a self-dual tensor is emphasized. The extension of this formalism to meet the covariance under the full Lorentz group is also discussed.

  3. Mobilestar field test program

    NASA Technical Reports Server (NTRS)

    Rubow, Wayne

    1988-01-01

    Various field tests were performed in order to gain practical experience and a broader understanding of mobile communications. The first phase consisted of CW propagation tests to develop firsthand experience of propagation phenomena. From this information, estimates of the feasibility and accuracy of power control were possible. The next phase tested the idea of power control. Equipment representative of that expected to be used in an actual mobile satellite communication system was assembled and tested under a variety of environments.

  4. Mobile Field Goniospectrometry

    NASA Astrophysics Data System (ADS)

    Peltoniemi, J. I.; Kaasalainen, S.; Näränen, J.

    2004-05-01

    Multiangle remote sensing needs multiangle models and multiangle ground reference data. The ground data can be measured using goniometers. Many targets are in difficult terrains and hard to bring into laboratory, which makes the ground data collection more complicated We have developed several field goniometers to measure the directional and spectral reflection signatures of various targets. The heaviest of the instruments is fully manual and very robust for field work. It can be transported using a light trailer and mounted in an hour. The new very light goniometer measures the BRDF automatically in few minutes. It can be carried by two persons even large distances to difficult places. Both of these instruments use the ASD Field Spec PRO FR spectrometer with a 4m light fibre allowing optics to be mounted up and the heavy parts down. The dimensions --- arm length about 2m --- and optics (1--8 degree view angles) limit the useful spot diameter to about 3, 10 or 30cm, making the system useful for small vegetation and soil. These two wide angle goniometers are complemented by a narrow angle backscattering goniometer utilising beamsplitters to measure up to exact backscattering direction and about 15 degree around. We present BRDF and spectra for undergrowth (lichen, moss, peat, twigs) from a field campaign in August 2003, and various grasses dry and wet. We recognise significant differences in the directional pattern between different species (factors of 2-10) and varying structural properties, making the use of directional signal for remote sensing very attractive. We are working with scattering models of snow and soil, and will continue with vegetation soon.

  5. Phase Field Fracture Mechanics.

    SciTech Connect

    Robertson, Brett Anthony

    2015-11-01

    For this assignment, a newer technique of fracture mechanics using a phase field approach, will be examined and compared with experimental data for a bend test and a tension test. The software being used is Sierra Solid Mechanics, an implicit/explicit finite element code developed at Sandia National Labs in Albuquerque, New Mexico. The bend test experimental data was also obtained at Sandia Labs while the tension test data was found in a report online from Purdue University.

  6. More Track and Field

    NASA Astrophysics Data System (ADS)

    Fatuzzo, Marco; Toepker, Terrence P.

    2004-09-01

    A recent item in Physics Challenges for Teachers and Students presented a problem of a metal rod (mass M) sliding on frictionless, parallel conducting rails (of negligible resistance and separated by a distance L) in the presence of a downwardly directed uniform external magnetic field B. A resistor R bridges the rails, thereby completing the circuit. This problem can also be found in Griffiths' text Introduction to Electrodynamics, 3rd ed. (Problem 7.7).2

  7. Fringe Field Superconducting Switch

    DTIC Science & Technology

    1997-10-31

    superconducting smp ,ine 10, and a ferromagnet ferromagnet 14 preferably has at least two easy axes of magnetization, shown here by the double- headed arrows...magnetic field of control current **p6fCooductor- S4 ’’/ eonteol^cun 7* insulator ■O Jöpptyzcöwem supercuiKhttstog-^2 ^ FIG.^ 4 //■ r.»~r

  8. Microbial Field Pilot Study

    SciTech Connect

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Chisholm, J.L.

    1990-11-01

    This report covers progress made during the first year of the Microbial Field Pilot Study project. Information on reservoir ecology and characterization, facility and treatment design, core experiments, bacterial mobility, and mathematical modeling are addressed. To facilitate an understanding of the ecology of the target reservoir analyses of the fluids which support bacteriological growth and the microbiology of the reservoir were performed. A preliminary design of facilities for the operation of the field pilot test was prepared. In addition, procedures for facilities installation and for injection treatments are described. The Southeast Vassar Vertz Sand Unit (SEVVSU), the site of the proposed field pilot study, is described physically, historically, and geologically. The fields current status is presented and the ongoing reservoir simulation is discussed. Core flood experiments conducted during the last year were used to help define possible mechanisms involved in microbial enhanced oil recovery. Two possible mechanisms, relative permeability effects and changes in the capillary number, are discussed and related to four Berea core experiments' results. The experiments were conducted at reservoir temperature using SEVVSU oil, brine, and bacteria. The movement and activity of bacteria in porous media were investigated by monitoring the growth of bacteria in sandpack cores under no flow conditions. The rate of bacteria advancement through the cores was determined. A mathematical model of the MEOR process has been developed. The model is a three phase, seven species, one dimensional model. Finite difference methods are used for solution. Advection terms in balance equations are represented with a third- order upwind differencing scheme to reduce numerical dispersion and oscillations. The model is applied to a batch fermentation example. 52 refs., 26 figs., 21 tabs.

  9. Magnetic field reconnection

    NASA Astrophysics Data System (ADS)

    Axford, W. I.

    The fundamental principles of particle acceleration by magnetic reconnection in cosmic plasmas are reviewed. The history of reconnection models is traced, and consideration is given to the Kelvin-Helmholtz theorem, the frozen-field theorem, the application of the Kelvin-Helmholtz theorem to a collisionless plasma, solutions to specific reconnection problems, and configurational instability. Diagrams and graphs are provided, and the objections raised by critics of the reconnection theory and/or its astrophysical applications are discussed.

  10. Microbial field pilot study

    SciTech Connect

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Chisholm, J.L.

    1992-03-01

    The objective of this project is to perform a microbial enhanced oil recovery field pilot in the Southeast Vassar Vertz Sand Unit (SEVVSU) in Payne County, Oklahoma. Indigenous, anaerobic, nitrate reducing bacteria will be stimulated to selectively plug flow paths which have been referentially swept by a prior waterflood. This will force future flood water to invade bypassed regions of the reservoir and increase sweep efficiency. This report covers progress made during the second year, January 1, 1990 to December 31, 1990, of the Microbial Field Pilot Study project. Information on reservoir ecology, surface facilities design, operation of the unit, core experiments, modeling of microbial processes, and reservoir characterization and simulation are presented in the report. To better understand the ecology of the target reservoir, additional analyses of the fluids which support bacteriological growth and the microbiology of the reservoir were performed. The results of the produced and injected water analysis show increasing sulfide concentrations with respect to time. In March of 1990 Mesa Limited Partnership sold their interest in the SEVVSU to Sullivan and Company. In April, Sullivan and Company assumed operation of the field. The facilities for the field operation of the pilot were refined and implementation was begun. Core flood experiments conducted during the last year were used to help define possible mechanisms involved in microbial enhanced oil recovery. The experiments were performed at SEVVSU temperature using fluids and inoculum from the unit. The model described in last year's report was further validated using results from a core flood experiment. The model was able to simulate the results of one of the core flood experiments with good quality.

  11. Microbial field pilot study

    SciTech Connect

    Knapp, R.M.; McInerney, M.J.; Menzie, D.E.; Chisholm, J.L.

    1992-03-01

    The objective of this project is to perform a microbial enhanced oil recovery field pilot in the Southeast Vassar Vertz Sand Unit (SEVVSU) in Payne County, Oklahoma. Indigenous, anaerobic, nitrate reducing bacteria will be stimulated to selectively plug flow paths which have been referentially swept by a prior waterflood. This will force future flood water to invade bypassed regions of the reservoir and increase sweep efficiency. This report covers progress made during the second year, January 1, 1990 to December 31, 1990, of the Microbial Field Pilot Study project. Information on reservoir ecology, surface facilities design, operation of the unit, core experiments, modeling of microbial processes, and reservoir characterization and simulation are presented in the report. To better understand the ecology of the target reservoir, additional analyses of the fluids which support bacteriological growth and the microbiology of the reservoir were performed. The results of the produced and injected water analysis show increasing sulfide concentrations with respect to time. In March of 1990 Mesa Limited Partnership sold their interest in the SEVVSU to Sullivan and Company. In April, Sullivan and Company assumed operation of the field. The facilities for the field operation of the pilot were refined and implementation was begun. Core flood experiments conducted during the last year were used to help define possible mechanisms involved in microbial enhanced oil recovery. The experiments were performed at SEVVSU temperature using fluids and inoculum from the unit. The model described in last year`s report was further validated using results from a core flood experiment. The model was able to simulate the results of one of the core flood experiments with good quality.

  12. Photonic Magnetic Field Sensor

    DTIC Science & Technology

    2007-11-02

    reduce feedback in fiber optic links can be the basis for excellent magnetic field sensors. Based on the giant magneto-optical ( GMO ) or Faraday...Squids are those based upon the giant magneto-optical ( GMO ) effect in ferrimagnetic materials or YIG garnets and the giant magneto-resistance (GMR...effect in manganese based compounds. The development of the GMO material was mostly motivated by the need for compact, in-line fiber optical

  13. Crater Floor Dune Field

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

    Our final dune image shows a small dune field inside an unnamed crater south of Nili Fossae.

    Image information: VIS instrument. Latitude 20.6, Longitude 79 East (281 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  14. Nili Patera Dune Field

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

    This VIS image shows a dune field within Nili Patera, the northern caldera of a large volcanic complex in Syrtis Major.

    Image information: VIS instrument. Latitude 9, Longitude 67 East (293 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. Magnetic Field Solver

    NASA Technical Reports Server (NTRS)

    Ilin, Andrew V.

    2006-01-01

    The Magnetic Field Solver computer program calculates the magnetic field generated by a group of collinear, cylindrical axisymmetric electromagnet coils. Given the current flowing in, and the number of turns, axial position, and axial and radial dimensions of each coil, the program calculates matrix coefficients for a finite-difference system of equations that approximates a two-dimensional partial differential equation for the magnetic potential contributed by the coil. The program iteratively solves these finite-difference equations by use of the modified incomplete Cholesky preconditioned-conjugate-gradient method. The total magnetic potential as a function of axial (z) and radial (r) position is then calculated as a sum of the magnetic potentials of the individual coils, using a high-accuracy interpolation scheme. Then the r and z components of the magnetic field as functions of r and z are calculated from the total magnetic potential by use of a high-accuracy finite-difference scheme. Notably, for the finite-difference calculations, the program generates nonuniform two-dimensional computational meshes from nonuniform one-dimensional meshes. Each mesh is generated in such a way as to minimize the numerical error for a benchmark one-dimensional magnetostatic problem.

  16. Heavy fields and gravity

    NASA Astrophysics Data System (ADS)

    Goon, Garrett

    2017-01-01

    We study the effects of heavy fields on 4D spacetimes with flat, de Sitter and anti-de Sitter asymptotics. At low energies, matter generates specific, calculable higher derivative corrections to the GR action which perturbatively alter the Schwarzschild-( A) dS family of solutions. The effects of massive scalars, Dirac spinors and gauge fields are each considered. The six-derivative operators they produce, such as ˜ R 3 terms, generate the leading corrections. The induced changes to horizon radii, Hawking temperatures and entropies are found. Modifications to the energy of large AdS black holes are derived by imposing the first law. An explicit demonstration of the replica trick is provided, as it is used to derive black hole and cosmological horizon entropies. Considering entropy bounds, it's found that scalars and fermions increase the entropy one can store inside a region bounded by a sphere of fixed size, but vectors lead to a decrease, oddly. We also demonstrate, however, that many of the corrections fall below the resolving power of the effective field theory and are therefore untrustworthy. Defining properties of black holes, such as the horizon area and Hawking temperature, prove to be remarkably robust against higher derivative gravitational corrections.

  17. Carter separable electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Lynden-Bell, D.

    2000-02-01

    The purely electromagnetic analogue in flat space of Kerr's metric in general relativity is only rarely considered. Here we carry out in flat space a programme similar to Carter's investigation of metrics in general relativity in which the motion of a charged particle is separable. We concentrate on the separability of the motion (be it classical, relativistic or quantum) of a charged particle in electromagnetic fields that lie in planes through an axis of symmetry. In cylindrical polar coordinates (t,R,φ,z) the four-vector potential takes the form [formmu2] is the unit toroidal vector. The forms of the functions Φ(R,z) and A(R,z) are sought that allow separable motion. This occurs for relativistic motion only when AR,Φ and A2-Φ2 are all of the separable form ζ(λ)-η(μ)]/(λ-μ), where ζ and η are arbitrary functions, and λ and μ are spheroidal coordinates or degenerations thereof. The special forms of A and Φ that allow this are deduced. They include the Kerr metric analogue, with E+iB=-∇{q[(r-ia).(r-ia)]-1/2}. Rather more general electromagnetic fields allow separation when the motion is non-relativistic. The investigation is extended to fields that lie in parallel planes. Connections to Larmor's theorem are remarked upon.

  18. Computational quantum field theory

    NASA Astrophysics Data System (ADS)

    Grobe, Rainer

    2006-05-01

    I will give an overview on recent attempts to solve the time-dependent Dirac equation for the electron-positron field operator. These numerical solutions permit a first temporally and spatially resolved insight into the mechanisms of how an electron-positron pair can be created from vacuum in a very strong force field. This approach has helped to illuminate a wide range of controversial questions. Some of these questions arise for complicated physical situations such as how an electron scatters off a supercritical potential barrier (Klein paradox). This requires the application of quantum field theory to study the combined effect of the pair-production due to the supercriticality of the potential together with the scattering at the barrier involving the Pauli-principle. Other phenomena include Schr"odinger's Zitterbewegung and the localization problem for a relativistic particle. This work has been supported by the NSF and Research Corporation. P. Krekora, K. Cooley, Q. Su and R. Grobe, Phys. Rev. Lett. 95, 070403 (2005). P. Krekora, Q. Su and R. Grobe, Phys. Rev. Lett. 93, 043004 (2004). P. Krekora, Q. Su and R. Grobe, Phys. Rev. Lett. 92, 040406 (2004).

  19. Bright field illumination system

    NASA Technical Reports Server (NTRS)

    Huber, Edward D. (Inventor)

    1998-01-01

    A Bright Field Illumination system for inspecting a range of characteristically different kinds of defects, depressions, and ridges in a selected material surface. The system has an illumination source placed near a first focus of an elliptical reflector. In addition, a camera facing the inspected area is placed near the illumination source and the first focus. The second focus of the elliptical reflector is located at a distance approximately twice the elliptical reflector's distance above the inspected surface. The elliptical reflector directs the light from the source onto the inspected surface. Due to the shape of the elliptical reflector, light that is specularly reflected from the inspected surface is directed into the camera is which located at the position of the reflected second focus of the ellipse. This system creates a brightly lighted background field against which damage sites appear as high contrast dark objects which can be easily detected by a person or an automated inspection system. In addition, the Bright Field Illumination system and method can be used in combination with a vision inspection system providing for multiplexed illumination and data handling of multiple kinds of surface characteristics including abrupt and gradual surface variations and differences between measured characteristics of different kinds and prior instruments.

  20. Field Trips: Tradition in Jeopardy

    ERIC Educational Resources Information Center

    Wheeler, Ginger

    2011-01-01

    The school field trip: something fun, different, exciting, exhausting--a break from the school day grind. But the field trip has ramifications beyond just getting out of school for the day. For students, the field trip is to the classroom what the big game is to athletes. For museums and other attractions, the field trip is a way to cultivate…

  1. Unbalanced field RF electron gun

    DOEpatents

    Hofler, Alicia

    2013-11-12

    A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.

  2. Generalized gravitational entropy of interacting scalar field and Maxwell field

    NASA Astrophysics Data System (ADS)

    Huang, Wung-Hong

    2014-12-01

    The generalized gravitational entropy proposed recently by Lewkowycz and Maldacena is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the area of horizon. The associated modified area law is consistent with the generalized gravitational entropy.

  3. Superhorizon magnetic fields

    NASA Astrophysics Data System (ADS)

    Campanelli, Leonardo

    2016-03-01

    We analyze the evolution of superhorizon-scale magnetic fields from the end of inflation till today. Whatever is the mechanism responsible for their generation during inflation, we find that a given magnetic mode with wave number k evolves, after inflation, according to the values of k ηe , nk , and Ωk , where ηe is the conformal time at the end of inflation, nk is the number density spectrum of inflation-produced photons, and Ωk is the phase difference between the two Bogoliubov coefficients which characterize the state of that mode at the end of inflation. For any realistic inflationary magnetogenesis scenario, we find that nk-1≪|k ηe|≪1 , and three evolutionary scenarios are possible: (i) |Ωk∓π |=O (1 ) , in which case the evolution of the magnetic spectrum Bk(η ) is adiabatic, a2Bk(η )=const , with a being the expansion parameter; (ii) |Ωk∓π |≪|k ηe| , in which case the evolution is superadiabatic, a2Bk(η )∝η ; (iii) |k ηe|≪|Ωk∓π |≪1 or |k ηe|˜|Ωk∓π |≪1 , in which case an early phase of adiabatic evolution is followed, after a time η⋆˜|Ωk∓π |/k , by a superadiabatic evolution. Once a given mode reenters the horizon, it remains frozen into the plasma and then evolves adiabatically till today. As a corollary of our results, we find that inflation-generated magnetic fields evolve adiabatically on all scales and for all times in conformal-invariant free Maxwell theory, while they evolve superadiabatically after inflation on superhorizon scales in the nonconformal-invariant Ratra model, where the inflaton is kinematically coupled to the electromagnetic field. The latter result supports and, somehow, clarifies our recent claim that the Ratra model can account for the presence of cosmic magnetic fields without suffering from both backreaction and strong-coupling problems.

  4. Aerial field guide

    NASA Technical Reports Server (NTRS)

    Nummedal, D.

    1978-01-01

    There are two overflights planned for the field conference; one for the Cheney-Palouse tract of the eastern channeled scabland, the other covering the coulees and basins of the western region. The approximate flight lines are indicated on the accompanying LANDSAT images. The first flight will follow the eastern margin of this large scabland tract, passing a series of loess remnants, gravel bars and excavated rock basins. The western scablands overflight will provide a review of the structurally controlled complex pattern of large-scale erosion and deposition characteristic of the region between the upper Grand Coulee (Banks Lake) and the Pasco Basin.

  5. Predicting photothermal field performance

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. C.; Ross, R. G., Jr.

    1984-01-01

    Photothermal field performance in flat plate solar collectors was predicted. An analytical model which incorporates the measured dependency between transmittance loss and UV and temperature exposure levels was developed. The model uses SOLMET weather data extrapolated to 30 years for various sites and module mounting configurations. It is concluded that the temperature is the key to photothermally induced transmittance loss. The sensitivity of transmittance loss to UV level is nonlinear with minimum in curve near one sun. The ethylene vinyl acetate (EVA) results are consistent with 30 year life allocation.

  6. Digital field ion microscopy

    SciTech Connect

    Sijbrandij, S.J.; Russell, K.F.; Miller, M.K.; Thomson, R.C.

    1998-01-01

    Due to environmental concerns, there is a trend to avoid the use of chemicals needed to develop negatives and to process photographic paper, and to use digital technologies instead. Digital technology also offers the advantages that it is convenient, as it enables quick access to the end result, allows image storage and processing on computer, allows rapid hard copy output, and simplifies electronic publishing. Recently significant improvements have been made to the performance and cost of camera-sensors and printers. In this paper, field ion images recorded with two digital cameras of different resolution are compared to images recorded on standard 35 mm negative film. It should be noted that field ion images exhibit low light intensity and high contrast. Field ion images were recorded from a standard microchannel plate and a phosphor screen and had acceptance angles of {approximately} 60{degree}. Digital recordings were made with a Digital Vision Technologies (DVT) MICAM VHR1000 camera with a resolution of 752 x 582 pixels, and a Kodak DCS 460 digital camera with a resolution of 3,060 x 2,036 pixels. Film based recordings were made with Kodak T-MAX film rated at 400 ASA. The resolving power of T-MAX film, as specified by Kodak, is between 50 and 125 lines per mm, which corresponds to between 1,778 x 1,181 and 4,445 x 2,953 pixels, i.e. similar to that from the DCS 460 camera. The intensities of the images were sufficient to be recorded with standard fl:1.2 lenses with exposure times of less than 2 s. Many digital cameras were excluded from these experiments due to their lack of sensitivity or the inability to record a full frame image due to the fixed working distance defined by the vacuum system. The digital images were output on a Kodak Digital Science 8650 PS dye sublimation color printer (300 dpi). All field ion micrographs presented were obtained from a Ni-Al-Be specimen.

  7. Transverse field focused system

    DOEpatents

    Anderson, Oscar A.

    1986-01-01

    A transverse field focused (TFF) system for transport or acceleration of an intense sheet beam of negative ions in which a serial arrangement of a plurality of pairs of concentric cylindrical-arc electrodes is provided. Acceleration of the sheet beam can be achieved by progressively increasing the mean electrode voltage of successive electrode pairs. Because the beam is curved by the electrodes, the system can be designed to transport the beam through a maze passage which is baffled to prevent line of sight therethrough. Edge containment of the beam can be achieved by shaping the side edges of the electrodes to produce an electric force vector directed inwardly from the electrode edges.

  8. Semiclassical Coulomb field

    SciTech Connect

    Polonyi, J.

    2008-06-15

    The contribution of different modes of the Coulomb field to decoherence and to the dynamical breakdown of the time reversal invariance is calculated in the one-loop approximation for nonrelativistic electron gas. The dominant contribution was found to come from the usual collective modes in the plasma, namely, the zero-sound and the plasmon oscillations. The length scale of the quantum-classical transition is found to be close to the Thomas-Fermi screening length. It is argued that the extension of these modes to the whole Fock space yields optimal pointer states.

  9. Reconnection of Magnetic Fields

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Spacecraft observations of steady and nonsteady reconnection at the magnetopause are reviewed. Computer simulations of three-dimensional reconnection in the geomagnetic tail are discussed. Theoretical aspects of the energization of particles in current sheets and of the microprocesses in the diffusion region are presented. Terrella experiments in which magnetospheric reconnection is simulated at both the magnetopause and in the tail are described. The possible role of reconnection in the evolution of solar magnetic fields and solar flares is discussed. A two-dimensional magnetohydrodynamic computer simulation of turbulent reconnection is examined. Results concerning reconnection in Tokamak devices are also presented.

  10. NFC - Narrow Field Camera

    NASA Astrophysics Data System (ADS)

    Koukal, J.; Srba, J.; Gorková, S.

    2015-01-01

    We have been introducing a low-cost CCTV video system for faint meteor monitoring and here we describe the first results from 5 months of two-station operations. Our system called NFC (Narrow Field Camera) with a meteor limiting magnitude around +6.5mag allows research on trajectories of less massive meteoroids within individual parent meteor showers and the sporadic background. At present 4 stations (2 pairs with coordinated fields of view) of NFC system are operated in the frame of CEMeNt (Central European Meteor Network). The heart of each NFC station is a sensitive CCTV camera Watec 902 H2 and a fast cinematographic lens Meopta Meostigmat 1/50 - 52.5 mm (50 mm focal length and fixed aperture f/1.0). In this paper we present the first results based on 1595 individual meteors, 368 of which were recorded from two stations simultaneously. This data set allows the first empirical verification of theoretical assumptions for NFC system capabilities (stellar and meteor magnitude limit, meteor apparent brightness distribution and accuracy of single station measurements) and the first low mass meteoroid trajectory calculations. Our experimental data clearly showed the capabilities of the proposed system for low mass meteor registration and for calculations based on NFC data to lead to a significant refinement in the orbital elements for low mass meteoroids.

  11. Measurement of radiofrequency fields

    SciTech Connect

    Leonowich, J.A.

    1992-05-01

    We are literally surrounded by radiofrequency (RFR) and microwave radiation, from both natural and man-made sources. The identification and control of man-made sources of RFR has become a high priority of radiation safety professionals in recent years. For the purposes of this paper, we will consider RFR to cover the frequencies from 3 kHz to 300 MHz, and microwaves from 300 MHz to 300 GHz, and will use the term RFR interchangeably to describe both. Electromagnetic radiation and field below 3 kHz is considered Extremely Low Frequency (ELF) and will not be discussed in this paper. Unlike x- and gamma radiation, RFR is non-ionizing. The energy of any RFR photon is insufficient to produce ionizations in matter. The measurement and control of RFR hazards is therefore fundamentally different from ionizing radiation. The purpose of this paper is to acquaint the reader with the fundamental issues involved in measuring and safely using RFR fields. 23 refs.

  12. Photonic Magnetic Field Sensor

    NASA Astrophysics Data System (ADS)

    Wyntjes, Geert

    2002-02-01

    Small, in-line polarization rotators or isolators to reduce feedback in fiber optic links can be the basis for excellent magnetic field sensors. Based on the giant magneto-optical (GMO) or Faraday effect in iron garnets, they with a magnetic field of a few hundred Gauss, (20 mT) for an interaction length for an optical beam of a few millimeters achieve a polarization rotation or phase shift of 45 deg (1/8 cycle). When powered by a small laser diode, with the induced linear phase shift recovered at the shot noise limit, we have demonstrated sensitivities at the 3.3 nT/Hz1/2 level for frequencies from less than 1 Hz to frequencies into the high kHz range. Through further improvements; an increase in interaction length, better materials and by far the greatest factor, the addition of a flux concentrator, sensitivities at the pT/Hz1/2 level appear to be within reach. We will detail such a design and discuss the issues that may limit achieving these goals.

  13. The Heliospheric Magnetic Field

    NASA Astrophysics Data System (ADS)

    Owens, Mathew J.; Forsyth, Robert J.

    2013-12-01

    The heliospheric magnetic field (HMF) is the extension of the coronal magnetic field carried out into the solar system by the solar wind. It is the means by which the Sun interacts with planetary magnetospheres and channels charged particles propagating through the heliosphere. As the HMF remains rooted at the solar photosphere as the Sun rotates, the large-scale HMF traces out an Archimedean spiral. This pattern is distorted by the interaction of fast and slow solar wind streams, as well as the interplanetary manifestations of transient solar eruptions called coronal mass ejections. On the smaller scale, the HMF exhibits an array of waves, discontinuities, and turbulence, which give hints to the solar wind formation process. This review aims to summarise observations and theory of the small- and large-scale structure of the HMF. Solar-cycle and cycle-to-cycle evolution of the HMF is discussed in terms of recent spacecraft observations and pre-spaceage proxies for the HMF in geomagnetic and galactic cosmic ray records.

  14. The Themis heliostat field

    NASA Astrophysics Data System (ADS)

    Collon, A.; Leclerc, A.

    The 201-heliostat field which supplies solar rays to the central receiver as part of the Themis project is detailed. Each heliostat has 54 sq m of surface and is connected with all others in a central control circuit. The energy is directed to a square aperture 4 m on a side. The control logic is written in three levels, with microprocessors located in each heliostat drive to follow commands of a central computer. The reflector field is subsequently divided into zones in order to maximize control efficiency and power deposition on the receiver as the day progresses. A maximum of 9.7 MWth is shone on the power tower at an operational efficiency of 77 percent. A cylindrical shape was chosen for the array, which turns face downward to survive in strong winds. Emergency procedures which would also cause the plant to shut down due to an accident in the primary loop are explored, along with hazards to human eyesight from seeing the reflected flux.

  15. Spectral Flat Fields

    NASA Astrophysics Data System (ADS)

    Kinney, Anne

    1990-12-01

    The diode to diode variations and photocathode non- uniformities of the FOS detectors were determined in SV for spectra obtained through the single apertures. Additional flat field calibrations will be performed in cycle 1 to verify stability and to extend the calibration to include the paired aperture spectra. In this test, we will obtain spectra of G191-B2B, which is known to have a very smooth, relatively featureless spectrum. The star will be observed in every useful detector/disperser combination through single apertures, and with the most useful dispersers at the photocathode locations corresponding to paired aperture spectra. Spatial scanning in the dispersion direction is used to shift the spectra, so that instrumental and features can be distinguished. The most useful polarizer configurations are also calibrated (excluding red side polarimetry and including blue side polarimetry for POL0-B but not for POL0-A). A second star, BD+28D4211, is also observed in the same manner, about 6 months later, to establish photometric and flat-field stability.

  16. The First Chandra Field

    SciTech Connect

    Weisskopf, Martin C.; Aldcroft, Thomas L.; Cameron, Robert A.; Gandhi, Poshak; Foellmi, Cedric; Elsner, Ronald F.; Patel, Sandeep K.; Wu, Kinwah; O'Dell, Stephen L.; /NASA, Marshall

    2005-09-09

    Before the official first-light images, the Chandra X-ray Observatory obtained an X-ray image of the field to which its focal plane was first exposed. We describe this historic observation and report our study of the first Chandra field. Chandra's Advanced CCD Imaging Spectrometer (ACIS) detected 15 X-ray sources, the brightest being dubbed ''Leon X-1'' to honor the Chandra Telescope Scientist, Leon Van Speybroeck. Based upon our analysis of the X-ray data and spectroscopy at the European Southern Observatory (ESO; La Silla, Chile), we find that Leon X-1 is a Type-1 (unobscured) active galactic nucleus (AGN) at a redshift z = 0.3207. Leon X-1 exhibits strong Fe II emission and a broad-line Balmer decrement that is unusually flat for an AGN. Within the context of the Eigenvector-1 correlation space, these properties suggest that Leon X-1 may be a massive ({ge} 10{sup 9} M{sub {circle_dot}}) black hole, accreting at a rate approaching its Eddington limit.

  17. The field worker's fields: ethics, ethnography and medical sociology.

    PubMed

    Anspach, Renée R; Mizrachi, Nissim

    2006-09-01

    Sociologists who do field work in medical settings face an intractable tension between their disciplinary field, which takes a critical perspective toward medicine, and their ethnographic field, which often includes physicians. This paper explores the ethical problems that result from the collision of the two fields. While in the field, ethnographers are forced to choose between sociology and their obligations to host members, as they decide whether to disclose their actual research agendas, whether to ask tough questions or to reveal their concerns, and whether to give advice. The tension persists when field workers leave the field to write, forcing them to choose between competing interpretations and to decide what to reveal or conceal in the interests of confidentiality. Through these moral choices about what to ask, record or present to the reader, ethnographers shape the academic field even as it shapes them.

  18. String theory in electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Ambjørn, Jan; Makeenko, Yuri M.; Semenoff, Gordon W.; Szabo, Richard J.

    2003-02-01

    A review of various aspects of superstrings in background electromagnetic fields is presented. Topics covered include the Born-Infeld action, spectrum of open strings in background gauge fields, the Schwinger mechanism, finite-temperature formalism and Hagedorn behaviour in external fields, Debye screening, D-brane scattering, thermodynamics of D-branes, and noncommutative field and string theories on D-branes. The electric field instabilities are emphasized throughout and contrasted with the case of magnetic fields. A new derivation of the velocity-dependent potential between moving D-branes is presented, as is a new result for the velocity corrections to the one-loop thermal effective potential.

  19. Field-dressed orbitals in strong-field molecular ionization

    NASA Astrophysics Data System (ADS)

    Siemering, Robert; Njoya, Oumarou; Weinacht, Thomas; de Vivie-Riedle, Regina

    2015-10-01

    We demonstrate the importance of considering the shape of field-dressed molecular orbitals in interpreting angle-dependent measures of strong-field ionization from excited states. Our calculations of angle-dependent ionization for three homologous polyatomic molecules with very similar valence orbitals show that one has to take into account the shape of the field-dressed orbitals rather than the field-free orbitals in order to rationalize the experimental measurements.

  20. Beyond mean field theory: statistical field theory for neural networks

    PubMed Central

    Buice, Michael A; Chow, Carson C

    2014-01-01

    Mean field theories have been a stalwart for studying the dynamics of networks of coupled neurons. They are convenient because they are relatively simple and possible to analyze. However, classical mean field theory neglects the effects of fluctuations and correlations due to single neuron effects. Here, we consider various possible approaches for going beyond mean field theory and incorporating correlation effects. Statistical field theory methods, in particular the Doi–Peliti–Janssen formalism, are particularly useful in this regard. PMID:25243014

  1. Electric-field and magnetic-field sensors

    NASA Astrophysics Data System (ADS)

    Wieckowski, T. W.

    1993-05-01

    Analysis of double-loaded loop antennas and their properties has led to the design of new measuring sensors which enable has led to determination of both electric field strength and magnetic field strength. Sensors of the design proposed are applicable to a quasipoint measurement providing independent determination of the electric and magnetic component of the field.

  2. High field superconducting magnets

    NASA Technical Reports Server (NTRS)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  3. Squishy Physics Field Trips

    NASA Astrophysics Data System (ADS)

    Weeks, Eric R.; Cianci, Gianguido; Habdas, Piotr

    2008-03-01

    Our laboratory studies soft condensed matter, which means we investigate squishy materials such as foams, emulsions, and colloidal suspensions. These materials include common things such as peanut butter, toothpaste, mayonnaise, shampoo, and shaving cream. We have conducted several field trips for grade school students, where they come to our laboratory and play with squishy materials. They do both hands-on table-top projects and also look at samples with a microscope. We have also developed some of these activities into labs appropriate for first-year college students. Our first goal for these activities is to show students that science is fun, and the second goal is to get them intrigued by the idea that there are more phases than just solids, liquids, and gases.

  4. Asymmetrical field emitter

    DOEpatents

    Fleming, J.G.; Smith, B.K.

    1995-10-10

    A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

  5. Oil field management system

    DOEpatents

    Fincke, James R.

    2003-09-23

    Oil field management systems and methods for managing operation of one or more wells producing a high void fraction multiphase flow. The system includes a differential pressure flow meter which samples pressure readings at various points of interest throughout the system and uses pressure differentials derived from the pressure readings to determine gas and liquid phase mass flow rates of the high void fraction multiphase flow. One or both of the gas and liquid phase mass flow rates are then compared with predetermined criteria. In the event such mass flow rates satisfy the predetermined criteria, a well control system implements a correlating adjustment action respecting the multiphase flow. In this way, various parameters regarding the high void fraction multiphase flow are used as control inputs to the well control system and thus facilitate management of well operations.

  6. Molecules in Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Berdyugina, Svetlana

    2015-08-01

    Molecules probe cool matter in the Universe and various astrophysical objects. Their ability to sense magnetic fields provides new insights into magnetic properties of these objects. During the past fifteen years we have carried out a theoretical study of molecular magnetic effects such as the Zeeman, Paschen-Back and Hanle effects and their applications for inferring magnetic structures and spatial inhomogeneities on the Sun, cool stars, brown dwarfs, and exoplanets from molecular spectro-polarimetry (e.g., Berdyugina 2011). Here, we present an overview of this study and compare our theoretical predictions with recent laboratory measurements of magnetic properties of some molecules. We present also a new web-based tool to compute molecular magnetic effects and polarized spectra which is supported by the ERC Advanced Grant HotMol.

  7. Star field simulator

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A Star Field Simulator has been developed to serve as a source of radiation for the ASTRO Star Tracker. The star tracker and simulator are components of a motion compensation test facility located at Marshall Space Flight Center in Huntsville, Alabama. Preflight tests and simulations using various levels of guide stars are performed in the test facility to establish performance of the motion compensation system before being used in a flight environment. The ASTRO Star Tracker operates over a wide dynamic range of irradiance corresponding to visual stellar magnitudes of -0.8 to 8. A minimum of three simulated guide stars with variable magnitudes are needed to fully test the Star Tracker performance under simulated mission conditions.

  8. Direct Field Acoustic Testing

    NASA Technical Reports Server (NTRS)

    Larkin, Paul; Goldstein, Bob

    2008-01-01

    This paper presents an update to the methods and procedures used in Direct Field Acoustic Testing (DFAT). The paper will discuss some of the recent techniques and developments that are currently being used and the future publication of a reference standard. Acoustic testing using commercial sound system components is becoming a popular and cost effective way of generating a required acoustic test environment both in and out of a reverberant chamber. This paper will present the DFAT test method, the usual setup and procedure and the development and use of a closed-loop, narrow-band control system. Narrow-band control of the acoustic PSD allows all standard techniques and procedures currently used in random control to be applied to acoustics and some examples are given. The paper will conclude with a summary of the development of a standard practice guideline that is hoped to be available in the first quarter of next year.

  9. Field et al. Redux.

    PubMed Central

    2013-01-01

    On 12 February 1988 (by coincidence Charles Darwin’s birthday), a paper published in Science by Katherine Field, Rudy Raff, and colleagues presented the first credible molecular analysis of metazoan phylogeny based on sequences from the small subunit ribosomal RNA gene (SSU). Here I examine the main conclusions reached in this manuscript. I reconstitute their dataset and, by recompiling software available in 1988, I consider how they might have achieved a more accurate tree. I show how three common methods to avoid systematic error - more data, careful taxon sampling and superior models of evolution - overcome the errors that exist in the original paper. This approach illustrates the basis of some of the major advances of the past 25 years resulting in our current understanding of animal phylogeny. PMID:23398689

  10. Metallic field effect transistors

    NASA Astrophysics Data System (ADS)

    Farooq, Hassan

    This thesis investigates the principle of operation behind metallic-field effect transistors (METFETs) through a systematic study of atomistic simulations performed on metallic bulk, nanowire and transistor structures. In particular, density functional theory (DFT) and non-equilibrium green's function (NEGF) based models were used to study the effect on the bandstructure and density of states of highly scaled metallic nanowires with varying parameters such as crystal orientation, cross-sectional area, and applied external bias. Similarly, the effect of varying similar parameters on the transfer and output characteristics of highly scaled metallic transistors was studied. Furthermore, oxide interfaces with metallic channels were investigated. The simulation results show that a gold METFET in the [100] crystal orientation has an I ON /IOFF ratio of 41, ION of 29.5microA and fT of 6.7THz, outperforming similarly sized MOSFETs as a promising alternative for use in high-frequency circuits.

  11. Asymmetrical field emitter

    DOEpatents

    Fleming, James G.; Smith, Bradley K.

    1995-01-01

    Providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure.

  12. Associative Hierarchical Random Fields.

    PubMed

    Ladický, L'ubor; Russell, Chris; Kohli, Pushmeet; Torr, Philip H S

    2014-06-01

    This paper makes two contributions: the first is the proposal of a new model-The associative hierarchical random field (AHRF), and a novel algorithm for its optimization; the second is the application of this model to the problem of semantic segmentation. Most methods for semantic segmentation are formulated as a labeling problem for variables that might correspond to either pixels or segments such as super-pixels. It is well known that the generation of super pixel segmentations is not unique. This has motivated many researchers to use multiple super pixel segmentations for problems such as semantic segmentation or single view reconstruction. These super-pixels have not yet been combined in a principled manner, this is a difficult problem, as they may overlap, or be nested in such a way that the segmentations form a segmentation tree. Our new hierarchical random field model allows information from all of the multiple segmentations to contribute to a global energy. MAP inference in this model can be performed efficiently using powerful graph cut based move making algorithms. Our framework generalizes much of the previous work based on pixels or segments, and the resulting labelings can be viewed both as a detailed segmentation at the pixel level, or at the other extreme, as a segment selector that pieces together a solution like a jigsaw, selecting the best segments from different segmentations as pieces. We evaluate its performance on some of the most challenging data sets for object class segmentation, and show that this ability to perform inference using multiple overlapping segmentations leads to state-of-the-art results.

  13. Exposure guidelines for magnetic fields

    SciTech Connect

    Miller, G.

    1987-12-01

    The powerful magnetic fields produced by a controlled fusion experiment at Lawrence Livermore National Laboratory (LLNL) necessitated the development of personnel-exposure guidelines for steady magnetic fields. A literature search and conversations with active researchers showed that it is currently possible to develop preliminary exposure guidelines for steady magnetic fields. An overview of the results of past research into the bioeffects of magnetic fields was compiled, along with a discussion of hazards that may be encountered by people with sickle-cell anemia or medical electronic and prosthetic implants. The LLNL steady magnetic-field exposure guidelines along with a review of developments concerning the safety of time-varying fields were also presented in this compilation. Guidelines developed elsewhere for time varying fields were also given. Further research is needed to develop exposure standards for both steady or time-varying fields.

  14. Performing the field necropsy examination.

    PubMed

    Mason, Gary L; Madden, Dennis J

    2007-11-01

    This article is designed to aid the practitioner by maximizing the effectiveness of field postmortem diagnostic investigations. Contents include an outline of the procedure for field necropsy of ruminants, recommended tools and supplies, and guidelines for sample collection and submission.

  15. Direct drive field actuator motors

    DOEpatents

    Grahn, A.R.

    1998-03-10

    A positive-drive field actuator motor is described which includes a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately. 62 figs.

  16. Correlation Based Geomagnetic Field Modeling

    NASA Astrophysics Data System (ADS)

    Holschneider, M.; Mauerberger, S.; Lesur, V.; Baerenzung, J.

    2015-12-01

    We present a new method for determining geomagnetic field models. It is based on the construction of an a priori correlation structure derived from our knowledge about characteristic length scales and sources of the geomagnetic field. The magnetic field measurements are then seen as correlated random variables too and the inversion process amounts to compute the a posteriori correlation structure using Bayes theorem. We show how this technique allows the statistical separation of the various field contributions and the assessment of their uncertainties.

  17. Martian external magnetic field proxies

    NASA Astrophysics Data System (ADS)

    Langlais, Benoit; Civet, Francois

    2015-04-01

    Mars possesses no dynamic magnetic field of internal origin as it is the case for the Earth or for Mercury. Instead Mars is characterized by an intense and localized magnetic field of crustal origin. This field is the result of past magnetization and demagnetization processes, and reflects its evolution. The Interplanetary Magnetic Field (IMF) interacts with Mars' ionized environment to create an external magnetic field. This external field is weak compared to lithospheric one but very dynamic, and may hamper the detailed analysis of the internal magnetic field at some places or times. Because there are currently no magnetic field measurements made at Mars' surface, it is not possible to directly monitor the external field temporal variability as it is done in Earth's ground magnetic observatories. In this study we examine to indirect ways of quantifying this external field. First we use the Advanced Composition Explorer (ACE) mission which measures the solar wind about one hour upstream of the bow-shock resulting from the interaction between the solar wind and the Earth's internal magnetic field. These measurements are extrapolated to Mars' position taking into account the orbital configurations of the Mars-Earth system and the velocity of particles carrying the IMF. Second we directly use Mars Global Surveyor magnetic field measurements to quantify the level of variability of the external field. We subtract from the measurements the internal field which is otherwise modeled, and bin the residuals first on a spatial and then on a temporal mesh. This allows to compute daily or semi daily index. We present a comparison of these two proxies and demonstrate their complementarity. We also illustrate our analysis by comparing our Martian external field proxies to terrestrial index at epochs of known strong activity. These proxies will especially be useful for upcoming magnetic field measurements made around or at the surface of Mars.

  18. Ideal Channel Field Effect Transistors

    DTIC Science & Technology

    2010-03-01

    to bring the electron energy in equilibrium with the local electric field, i.e. the electron energy lags the local electric field. This non...equilibrium effect makes the impact ionization depend mostly on the carrier energy instead of the local electric field. The electron kinetic energy (E - Ec...the peak of the electron energy does not happen at the peak local electric field. Therefore the breakdown voltage was calculated using a non- local

  19. Direct drive field actuator motors

    SciTech Connect

    Grahn, Allen R.

    1998-01-01

    A positive-drive field actuator motor including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately.

  20. On Pfaffian Random Point Fields

    NASA Astrophysics Data System (ADS)

    Kargin, V.

    2014-02-01

    We study Pfaffian random point fields by using the Moore-Dyson quaternion determinants. First, we give sufficient conditions that ensure that a self-dual quaternion kernel defines a valid random point field, and then we prove a CLT for Pfaffian point fields. The proofs are based on a new quaternion extension of the Cauchy-Binet determinantal identity. In addition, we derive the Fredholm determinantal formulas for the Pfaffian point fields which use the quaternion determinant.

  1. Relation between near field and far field acoustic measurements

    NASA Technical Reports Server (NTRS)

    Bies, D. A.; Scharton, T. D.

    1974-01-01

    Several approaches to the problem of determining the far field directivity of an acoustic source located in a reverberant environment, such as a wind tunnel, are investigated analytically and experimentally. The decrease of sound pressure level with distance is illustrated; and the spatial extent of the hydrodynamic and geometric near fields, the far field, and the reverberant field are described. A previously-prosposed analytical technique for predicting the far field directivity of the acoustic source on the basis of near field data is investigated. Experiments are conducted with small acoustic sources and an analysis is performed to determine the variation with distance from the source of the directionality of the sound field. A novel experiment is conducted in which the sound pressure measured at various distances from an acoustic driver located in the NASA Ames 40 x 80 ft wind tunnel is crosscorrelated with the driver excitation voltage.

  2. Force-Field Parameter Fitter

    SciTech Connect

    2015-05-27

    ParFit is a flexible and extendable framework and library of classes for fitting force-field parameters to data from high-level ab-initio calculations on the basis of deterministic and stochastic algorithms. Currently, the code is fitting MM3 and Merck force-field parameters but could easily extend to other force-field types.

  3. Numerical calculations of flow fields

    NASA Technical Reports Server (NTRS)

    Anderson, D.; Vogel, J. M.

    1973-01-01

    Numerical calculations were made of flow fields generated by various aerodynamic configurations. Data cover flow fields generated by a finitely thick lifting three dimensional wing with subsonic tips moving at supersonic speeds, cross flow instability associated with lifting delta wing configurations such as space shuttles, and flow fields produced by a lifting elliptic cone. Finite difference techniques were used to determine elliptic cone flow.

  4. Lattice QCD in Background Fields

    SciTech Connect

    William Detmold, Brian Tiburzi, Andre Walker-Loud

    2009-06-01

    Electromagnetic properties of hadrons can be computed by lattice simulations of QCD in background fields. We demonstrate new techniques for the investigation of charged hadron properties in electric fields. Our current calculations employ large electric fields, motivating us to analyze chiral dynamics in strong QED backgrounds, and subsequently uncover surprising non-perturbative effects present at finite volume.

  5. Computer Based Virtual Field Trips.

    ERIC Educational Resources Information Center

    Clark, Kenneth F.; Hosticka, Alice; Schriver, Martha; Bedell, Jackie

    This paper discusses computer based virtual field trips that use technologies commonly found in public schools in the United States. The discussion focuses on the advantages of both using and creating these field trips for an instructional situation. A virtual field trip to Cumberland Island National Seashore, St. Marys, Georgia is used as a point…

  6. Double Gamers: Academics between Fields

    ERIC Educational Resources Information Center

    Costa, Cristina

    2016-01-01

    The field of academia is frequently associated with traditional norms that aim to regulate scholarly activity, especially research. The social web, as another field, is often viewed as challenging long-established conventions with novel knowledge production practices. Hence, the two fields seem to oppose rather than complement each other. Using a…

  7. Magnetic Field Topology in Jets

    NASA Technical Reports Server (NTRS)

    Gardiner, T. A.; Frank, A.

    2000-01-01

    We present results on the magnetic field topology in a pulsed radiative. jet. For initially helical magnetic fields and periodic velocity variations, we find that the magnetic field alternates along the, length of the jet from toroidally dominated in the knots to possibly poloidally dominated in the intervening regions.

  8. Low field magnetic resonance imaging

    SciTech Connect

    Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

    2010-07-13

    A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

  9. Light fields in the ocean

    NASA Technical Reports Server (NTRS)

    Pelevin, V. N.; Kozlyaninov, M. V.

    1981-01-01

    The problem of light fields in the ocean is in basic ocean optics. Twenty-six separate studies discuss: (1) the field of solar radiation in the ocean; (2) stationary and nonstationary light fields created in the sea by artificial sources; and (3) the use of optical methods to study biological and hydrodynamic characteristics of the sea.

  10. Magnetic-field-dosimetry system

    DOEpatents

    Lemon, D.K.; Skorpik, J.R.; Eick, J.L.

    1981-01-21

    A device is provided for measuring the magnetic field dose and peak field exposure. The device includes three Hall-effect sensors all perpendicular to each other, sensing the three dimensional magnetic field and associated electronics for data storage, calculating, retrieving and display.

  11. VELETA 2002 Field Campaign.

    NASA Astrophysics Data System (ADS)

    Alados-Arboledas, L.; Veleta2002 Team

    2003-04-01

    Depletion of the Earth's ozone layer is considered responsible of an increase in the solar ultraviolet irradiance incoming at surface level (WMO, 1998). For this reason, it is important to know the amount of ultraviolet radiation received by plants and animal organisms to evaluate the potential impact of increased UV radiation on biological systems. During recent years several studies has investigated the differences in UV radiation between places located at different altitude. Depending on the choice of the experimental area altitudinal gradients in erythemal UV have been reported ranging from 0.08 to 0.40 at different regions. Rather high altitudinal gradients were obtained when the studies have been undertaken at sites with important tropospheric pollution or when snow cover was present in the high-level sites. In this sense, it seems of interest to study these altitudinal gradients including comprehensive observations of the environmental conditions relevant to the incoming UV irradiance in order to separate the different contributions to this altitudinal effect. This paper presents the field campaign VELETA2002 (eValuation of the Effects of eLevation and aErosols on the ultravioleT rAdiation), developed during the month of July 2002 in the area of Sierra Nevada (Spain). This field campaign was designed to obtain experimental data on elevation and atmospheric aerosol effects on the solar ultraviolet irradiance. For this purpose a set of radiometers and spectroradiometers has been installed at both slopes of Sierra Nevada Massif, from coastal to inland locations. The field stations include Motril, a coastal location at sea level, Pitres (1200 m a.s.l.) located in the South slope of Sierra Nevada Massif, the Veleta Peak (3398 m a.s.l.), Las Sabinas (2200 m a.s.l.) located on the north slope of the mountain range and Armilla (680 m a.s.l.) located in the valley. The principal feature of the locations is that they provide a strong altitudinal gradient considering

  12. Magnetic fields in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Beck, Rainer

    2015-12-01

    Radio synchrotron emission, its polarization and Faraday rotation of the polarization angle are powerful tools to study the strength and structure of magnetic fields in galaxies. Unpolarized synchrotron emission traces isotropic turbulent fields which are strongest in spiral arms and bars (20-30 \\upmu G) and in central starburst regions (50-100 \\upmu G). Such fields are dynamically important; they affect gas flows and drive gas inflows in central regions. Polarized emission traces ordered fields, which can be regular or anisotropic turbulent, where the latter originates from isotropic turbulent fields by the action of compression or shear. The strongest ordered fields (10-15 \\upmu G) are generally found in interarm regions. In galaxies with strong density waves, ordered fields are also observed at the inner edges of spiral arms. Ordered fields with spiral patterns exist in grand-design, barred and flocculent galaxies and in central regions. Ordered fields in interacting galaxies have asymmetric distributions and are a tracer of past interactions between galaxies or with the intergalactic medium.—Faraday rotation measures of the diffuse polarized radio emission from galaxy disks reveal large-scale spiral patterns that can be described by the superposition of azimuthal modes; these are signatures of regular fields generated by mean-field dynamos. "Magnetic arms" between gaseous spiral arms may also be products of dynamo action, but need a stable spiral pattern to develop. Helically twisted field loops winding around spiral arms were found in two galaxies so far. Large-scale field reversals, like the one found in the Milky Way, could not yet be detected in external galaxies. In radio halos around edge-on galaxies, ordered magnetic fields with X-shaped patterns are observed. The origin and evolution of cosmic magnetic fields, in particular their first occurrence in young galaxies and their dynamical importance during galaxy evolution, will be studied with

  13. Overview - Electric fields. [in magnetosphere

    NASA Technical Reports Server (NTRS)

    Cauffman, D. P.

    1979-01-01

    The electric fields session is designed to review progress in observation, theory, and modeling of magnetospheric electric fields, and to expose important new results. The present report comments on the state and prospects of electric field research, with particular emphasis on relevance to quantitative modeling of the magnetospheric processes. Attention is given to underlying theories and models. Modeling philosophy is discussed relative to explanatory models and representative models. Modeling of magnetospheric electric fields, while in its infancy, is developing rapidly on many fronts employing a variety of approaches. The general topic of magnetospheric electric fields is becoming of prime importance in understanding space plasmas.

  14. Field practice internship final report

    SciTech Connect

    Foster, T.

    1994-05-01

    This field practice internship final report gives an overview of the field practice, which was completed at the Oak Ridge Y-12 Plant, Martin Marietta Energy Systems, Inc., Environmental Management Department, Oak Ridge, Tennessee. The field practice focused on the completion of the Superfund Amendments and Reauthorization Act (SARA) Title III, Emergency Planning and Community Right-to-Know Act Section 312, Tier II Report. The field practice internship was conducted on a full-time basis between December 13, 1993 through February 18, 1994. Sheila Poligone, Emergency Planning and Community Right-to-Know Act (EPCRA) Coordinator served as the field practice preceptor.

  15. Field Model: An Object-Oriented Data Model for Fields

    NASA Technical Reports Server (NTRS)

    Moran, Patrick J.

    2001-01-01

    We present an extensible, object-oriented data model designed for field data entitled Field Model (FM). FM objects can represent a wide variety of fields, including fields of arbitrary dimension and node type. FM can also handle time-series data. FM achieves generality through carefully selected topological primitives and through an implementation that leverages the potential of templated C++. FM supports fields where the nodes values are paired with any cell type. Thus FM can represent data where the field nodes are paired with the vertices ("vertex-centered" data), fields where the nodes are paired with the D-dimensional cells in R(sup D) (often called "cell-centered" data), as well as fields where nodes are paired with edges or other cell types. FM is designed to effectively handle very large data sets; in particular FM employs a demand-driven evaluation strategy that works especially well with large field data. Finally, the interfaces developed for FM have the potential to effectively abstract field data based on adaptive meshes. We present initial results with a triangular adaptive grid in R(sup 2) and discuss how the same design abstractions would work equally well with other adaptive-grid variations, including meshes in R(sup 3).

  16. Electronic field permeameter

    DOEpatents

    Chandler, Mark A.; Goggin, David J.; Horne, Patrick J.; Kocurek, Gary G.; Lake, Larry W.

    1989-01-01

    For making rapid, non-destructive permeability measurements in the field, a portable minipermeameter of the kind having a manually-operated gas injection tip is provided with a microcomputer system which operates a flow controller to precisely regulate gas flow rate to a test sample, and reads a pressure sensor which senses the pressure across the test sample. The microcomputer system automatically turns on the gas supply at the start of each measurement, senses when a steady-state is reached, collects and records pressure and flow rate data, and shuts off the gas supply immediately after the measurement is completed. Preferably temperature is also sensed to correct for changes in gas viscosity. The microcomputer system may also provide automatic zero-point adjustment, sensor calibration, over-range sensing, and may select controllers, sensors, and set-points for obtaining the most precise measurements. Electronic sensors may provide increased accuracy and precision. Preferably one microcomputer is used for sensing instrument control and data collection, and a second microcomputer is used which is dedicated to recording and processing the data, selecting the sensors and set-points for obtaining the most precise measurements, and instructing the user how to set-up and operate the minipermeameter. To provide mass data collection and user-friendly operation, the second microcomputer is preferably a lap-type portable microcomputer having a non-volatile or battery-backed CMOS memory.

  17. Paper field effect transistor

    NASA Astrophysics Data System (ADS)

    Fortunato, E.; Correia, Nuno; Barquinha, Pedro; Costa, Cláudia; Pereira, Luís; Gonçalves, Gonçalo; Martins, Rodrigo

    2009-02-01

    In this paper we report the use of a sheet of cellulose fiber-based paper as the dielectric layer used in oxide based semiconductor thin film field-effect transistors (FETs). In this new approach we are using the cellulose fiber-based paper in an "interstrate" structure since the device is build on both sides of the cellulose sheet. Such hybrid FETs present excellent operating characteristics such as high channel saturation mobility (>30 cm2/Vs), drain-source current on/off modulation ratio of approximately 104, near-zero threshold voltage, enhancement n-type operation and sub-threshold gate voltage swing of 0.8 V/decade. The cellulose fiber-based paper FETs characteristics have been measured in air ambient conditions and present good stability. The obtained results outpace those of amorphous Si TFTs and rival with the same oxide based TFTs produced on either glass or crystalline silicon substrates. The compatibility of these devices with large-scale/large-area deposition techniques and low cost substrates as well as their very low operating bias delineates this as a promising approach to attain high-performance disposable electronics like paper displays, smart labels, smart packaging, RFID and point-of-care systems for self analysis in bio-applications, among others.

  18. Megagauss Fields During Milliseconds

    SciTech Connect

    Campbell, L.J.; Embury, D.; Han, K.; Parkin, D.M.; Baca, A.; Kihara, K.H.; Sims, J.R.; Boebinger, G.S.; Eyssa, Y.; Lesch, B.; Li, L.; Schillig, J.B.; Schneider-Muntau, H.; Walsh, R.

    1998-10-18

    A non-destructive, one megagauss magnet is now being designed in cooperation between Los Alamos and the National High Magnetic Field Laboratory (NHMFL) through joint funding by the US Department of Energy and the US NSF. The design combines two types of pulsed magnet now in use at the NHMFL: a capacitor-driven 'insert' magnet with a total pulse width of order 10 ms and a much larger 'outsert' magnet with a total pulse width of order 2 seconds that is driven by a controlled power source. The insert and outsert produce approximately 1/2 megagauss each. Although the design uses CuAg as the principal conductor further design efforts and materials development are exploring CuNb and stainless steel-clad copper as possible future alternatives. A crucial innovation was to employ wound steel strip (sheet) as a reinforcement in both insert and outsert coils. This gives extra strength due to the higher degree of cold-work possible in strip materials. For this leading edge magnet a key role is played by materials development. A major component, the 7 module 560 MVA controlled dc power supply required for the outsert, has been installed and commissioned.

  19. Airborne field strength monitoring

    NASA Astrophysics Data System (ADS)

    Bredemeyer, J.; Kleine-Ostmann, T.; Schrader, T.; Münter, K.; Ritter, J.

    2007-06-01

    In civil and military aviation, ground based navigation aids (NAVAIDS) are still crucial for flight guidance even though the acceptance of satellite based systems (GNSS) increases. Part of the calibration process for NAVAIDS (ILS, DME, VOR) is to perform a flight inspection according to specified methods as stated in a document (DOC8071, 2000) by the International Civil Aviation Organization (ICAO). One major task is to determine the coverage, or, in other words, the true signal-in-space field strength of a ground transmitter. This has always been a challenge to flight inspection up to now, since, especially in the L-band (DME, 1GHz), the antenna installed performance was known with an uncertainty of 10 dB or even more. In order to meet ICAO's required accuracy of ±3 dB it is necessary to have a precise 3-D antenna factor of the receiving antenna operating on the airborne platform including all losses and impedance mismatching. Introducing precise, effective antenna factors to flight inspection to achieve the required accuracy is new and not published in relevant papers yet. The authors try to establish a new balanced procedure between simulation and validation by airborne and ground measurements. This involves the interpretation of measured scattering parameters gained both on the ground and airborne in comparison with numerical results obtained by the multilevel fast multipole algorithm (MLFMA) accelerated method of moments (MoM) using a complex geometric model of the aircraft. First results will be presented in this paper.

  20. Field Friendly Tuberculosis Biosensor

    NASA Astrophysics Data System (ADS)

    Proper, N.; Scherman, M. S.; Jevsevar, K. L.; Stone, J.; McNeil, M. R.; Krapf, D.

    2009-10-01

    Tuberculosis (TB) is a fading threat in the United States, but in the developing world it is still a major health-care concern. Given the rising number of cases and lack of resources, there is a desperate need for an affordable, portable detection system. We are working towards the development of a field-friendly immunological biosensor that utilizes florescence microscopy to undertake this task. We observe fluorescently labeled antibodies/antigens as they bind to a glass slide treated with polyethylene glycol (PEG) in order to inhibit non-specific adsorption. Antibodies against the antigens of interest are bound to the PEGylated glass slides via biotin-streptavidin interactions. Then, fluorescently labeled antibodies are mixed with different concentrations of TB antigens and this solution is incubated on the treated glass slides for 30 minutes. The slides are thoroughly rinsed with water following the incubation period. The antigens are then detected by fluorescence using a low-cost biosensor. Our system includes a ``supermarket-scanner'' HeNe laser, home-built electronics, off-the-shelf optics and a Si photodiode. Work is underway to incorporate a flow-cell into the system, in a small portable box.

  1. Field Deployable DNA analyzer

    SciTech Connect

    Wheeler, E; Christian, A; Marion, J; Sorensen, K; Arroyo, E; Vrankovich, G; Hara, C; Nguyen, C

    2005-02-09

    This report details the feasibility of a field deployable DNA analyzer. Steps for swabbing cells from surfaces and extracting DNA in an automatable way are presented. Since enzymatic amplification reactions are highly sensitive to environmental contamination, sample preparation is a crucial step to make an autonomous deployable instrument. We perform sample clean up and concentration in a flow through packed bed. For small initial samples, whole genome amplification is performed in the packed bed resulting in enough product for subsequent PCR amplification. In addition to DNA, which can be used to identify a subject, protein is also left behind, the analysis of which can be used to determine exposure to certain substances, such as radionuclides. Our preparative step for DNA analysis left behind the protein complement as a waste stream; we determined to learn if the proteins themselves could be analyzed in a fieldable device. We successfully developed a two-step lateral flow assay for protein analysis and demonstrate a proof of principle assay.

  2. The Styx field trial

    PubMed Central

    Gemmell, M. A.

    1968-01-01

    An assessment was made of the effectiveness of the generally accepted methods recommended for controlling hydatid disease during the course of a field-trial, initiated in 1943 in an isolated region of New Zealand. The results obtained during the first 21 years are described. Basically, the trial was an attempt to compare the effectiveness of a general public health educational programme and an anthelmintic programme using arecoline hydrobromide for treatment of dogs with that of a specific educational programme using this compound as a diagnostic agent. Arecoline hydrobromide was found to be too uncertain in its action to be of practical value as an anthelmintic. The development of diagnostic techniques, described in this paper, made it possible to use the compound for diagnostic purposes and thus for educational purposes, since each dog could be examined for tapeworms in the presence of the owner. Using changes in the annual prevalence rate in sheep of the cysts of E. granulosus and those of T. hydatigena as the principal indicators, the conclusion has been reached that the specific diagnostic approach achieved more success than the general educational and treatment programme. The principal reason for this appears to be that the former approach induced a greater awareness in owners of the need for strict management to prevent dogs gaining access to infective raw offal than that stimulated in the community when the dogs were dosed but not examined. ImagesFIG. 2FIG. 4FIG. 5 PMID:5303843

  3. RESOLVE 2010 Field Test

    NASA Technical Reports Server (NTRS)

    Captain, J.; Quinn, J.; Moss, T.; Weis, K.

    2010-01-01

    This slide presentation reviews the field tests conducted in 2010 of the Regolith Environment Science & Oxygen & Lunar Volatile Extraction (RESOLVE). The Resolve program consist of several mechanism: (1) Excavation and Bulk Regolith Characterization (EBRC) which is designed to act as a drill and crusher, (2) Regolith Volatiles Characterization (RVC) which is a reactor and does gas analysis,(3) Lunar Water Resources Demonstration (LWRD) which is a fluid system, water and hydrogen capture device and (4) the Rover. The scientific goal of this test is to demonstrate evolution of low levels of hydrogen and water as a function of temperature. The Engineering goals of this test are to demonstrate:(1) Integration onto new rover (2) Miniaturization of electronics rack (3) Operation from battery packs (elimination of generator) (4) Remote command/control and (5) Operation while roving. Views of the 2008 and the 2010 mechanisms, a overhead view of the mission path, a view of the terrain, the two drill sites, and a graphic of the Master Events Controller Graphical User Interface (MEC GUI) are shown. There are descriptions of the Gas chromatography (GC), the operational procedure, water and hydrogen doping of tephra. There is also a review of some of the results, and future direction for research and tests.

  4. Vector fields in multidimensional cosmology

    NASA Astrophysics Data System (ADS)

    Meierovich, Boris E.

    2011-09-01

    Vector fields in the expanding Universe are considered within the multidimensional theory of general relativity. Vector fields in general relativity form a three-parametric variety. Our consideration includes the fields with a nonzero covariant divergence. Depending on the relations between the particular parameters and the symmetry of a problem, the vector fields can be longitudinal and/or transverse, ultrarelativistic (i.e. massless) or nonrelativistic (massive), and so on. The longitudinal and transverse vector fields are considered separately in detail in the background of the de Sitter cosmological metric. In most cases the field equations reduce to Bessel equations, and their temporal evolution is analyzed analytically. The energy-momentum tensor of the most simple zero-mass longitudinal vector fields enters the Einstein equations as an additive to the cosmological constant. In this case the de Sitter metric is the exact solution of the Einstein equations. Hence, the most simple zero-mass longitudinal vector field pretends to be an adequate tool for macroscopic description of dark energy as a source of the expansion of the Universe at a constant rate. The zero-mass vector field does not vanish in the process of expansion. On the contrary, massive fields vanish with time. Though their amplitude is falling down, the massive fields make the expansion accelerated.

  5. Logarithmic conformal field theory

    NASA Astrophysics Data System (ADS)

    Gainutdinov, Azat; Ridout, David; Runkel, Ingo

    2013-12-01

    Conformal field theory (CFT) has proven to be one of the richest and deepest subjects of modern theoretical and mathematical physics research, especially as regards statistical mechanics and string theory. It has also stimulated an enormous amount of activity in mathematics, shaping and building bridges between seemingly disparate fields through the study of vertex operator algebras, a (partial) axiomatisation of a chiral CFT. One can add to this that the successes of CFT, particularly when applied to statistical lattice models, have also served as an inspiration for mathematicians to develop entirely new fields: the Schramm-Loewner evolution and Smirnov's discrete complex analysis being notable examples. When the energy operator fails to be diagonalisable on the quantum state space, the CFT is said to be logarithmic. Consequently, a logarithmic CFT is one whose quantum space of states is constructed from a collection of representations which includes reducible but indecomposable ones. This qualifier arises because of the consequence that certain correlation functions will possess logarithmic singularities, something that contrasts with the familiar case of power law singularities. While such logarithmic singularities and reducible representations were noted by Rozansky and Saleur in their study of the U (1|1) Wess-Zumino-Witten model in 1992, the link between the non-diagonalisability of the energy operator and logarithmic singularities in correlators is usually ascribed to Gurarie's 1993 article (his paper also contains the first usage of the term 'logarithmic conformal field theory'). The class of CFTs that were under control at this time was quite small. In particular, an enormous amount of work from the statistical mechanics and string theory communities had produced a fairly detailed understanding of the (so-called) rational CFTs. However, physicists from both camps were well aware that applications from many diverse fields required significantly more

  6. Hyperbolic-symmetry vector fields.

    PubMed

    Gao, Xu-Zhen; Pan, Yue; Cai, Meng-Qiang; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2015-12-14

    We present and construct a new kind of orthogonal coordinate system, hyperbolic coordinate system. We present and design a new kind of local linearly polarized vector fields, which is defined as the hyperbolic-symmetry vector fields because the points with the same polarization form a series of hyperbolae. We experimentally demonstrate the generation of such a kind of hyperbolic-symmetry vector optical fields. In particular, we also study the modified hyperbolic-symmetry vector optical fields with the twofold and fourfold symmetric states of polarization when introducing the mirror symmetry. The tight focusing behaviors of these vector fields are also investigated. In addition, we also fabricate micro-structures on the K9 glass surfaces by several tightly focused (modified) hyperbolic-symmetry vector fields patterns, which demonstrate that the simulated tightly focused fields are in good agreement with the fabricated micro-structures.

  7. Magnetospheric electric fields and currents

    NASA Technical Reports Server (NTRS)

    Mauk, B. H.; Zanetti, L. J.

    1987-01-01

    The progress made in the years 1983-1986 in understanding the character and operation of magnetospheric electric fields and electric currents is discussed, with emphasis placed on the connection with the interior regions. Special attention is given to determinations of global electric-field configurations, measurements of the response of magnetospheric particle populations to the electric-field configurations, and observations of the magnetospheric currents at high altitude and during northward IMF. Global simulations of current distributions are discussed, and the sources of global electric fields and currents are examined. The topics discussed in the area of impulsive and small-scale phenomena include substorm current systems, impulsive electric fields and associated currents, and field-aligned electrodynamics. A key finding of these studies is that the electric fields and currents are interrelated and cannot be viewed as separate entities.

  8. Magnetic field switchable dry adhesives.

    PubMed

    Krahn, Jeffrey; Bovero, Enrico; Menon, Carlo

    2015-02-04

    A magnetic field controllable dry adhesive device is manufactured. The normal adhesion force can be increased or decreased depending on the presence of an applied magnetic field. If the magnetic field is present during the entire normal adhesion test cycle which includes both applying a preloading force and measuring the pulloff pressure, a decrease in adhesion is observed when compared to when there is no applied magnetic field. Similarly, if the magnetic field is present only during the preload portion of the normal adhesion test cycle, a decrease in adhesion is observed because of an increased stiffness of the magnetically controlled dry adhesive device. When the applied magnetic field is present during only the pulloff portion of the normal adhesion test cycle, either an increase or a decrease in normal adhesion is observed depending on the direction of the applied magnetic field.

  9. Whistler Modes with Wave Magnetic Fields Exceeding the Ambient Field

    SciTech Connect

    Stenzel, R.L.; Urrutia, J.M.; Strohmaier, K.D.

    2006-03-10

    Whistler-mode wave packets with fields exceeding the ambient dc magnetic field have been excited in a large, high electron-beta plasma. The waves are induced with a loop antenna with dipole moment either along or opposite to the dc field. In the latter case the excited wave packets have the topology of a spheromak but are propagating in the whistler mode along and opposite to the dc magnetic field. Field-reversed configurations with net zero helicity have also been produced. The electron magnetohydrodynamics fields are force free, have wave energy density exceeding the particle energy density, and propagate stably at subelectron thermal velocities through a nearly uniform stationary ion density background.

  10. Whistler modes with wave magnetic fields exceeding the ambient field.

    PubMed

    Stenzel, R L; Urrutia, J M; Strohmaier, K D

    2006-03-10

    Whistler-mode wave packets with fields exceeding the ambient dc magnetic field have been excited in a large, high electron-beta plasma. The waves are induced with a loop antenna with dipole moment either along or opposite to the dc field. In the latter case the excited wave packets have the topology of a spheromak but are propagating in the whistler mode along and opposite to the dc magnetic field. Field-reversed configurations with net zero helicity have also been produced. The electron magnetohydrodynamics fields are force free, have wave energy density exceeding the particle energy density, and propagate stably at subelectron thermal velocities through a nearly uniform stationary ion density background.

  11. The Swarm Initial Field Model for the 2014 Geomagnetic Field

    NASA Technical Reports Server (NTRS)

    Olsen, Nils; Hulot, Gauthier; Lesur, Vincent; Finlay, Christopher C.; Beggan, Ciaran; Chulliat, Arnaud; Sabaka, Terence J.; Floberghagen, Rune; Friis-Christensen, Eigil; Haagmans, Roger

    2015-01-01

    Data from the first year of ESA's Swarm constellation mission are used to derive the Swarm Initial Field Model (SIFM), a new model of the Earth's magnetic field and its time variation. In addition to the conventional magnetic field observations provided by each of the three Swarm satellites, explicit advantage is taken of the constellation aspect by including east-west magnetic intensity gradient information from the lower satellite pair. Along-track differences in magnetic intensity provide further information concerning the north-south gradient. The SIFM static field shows excellent agreement (up to at least degree 60) with recent field models derived from CHAMP data, providing an initial validation of the quality of the Swarm magnetic measurements. Use of gradient data improves the determination of both the static field and its secular variation, with the mean misfit for east-west intensity differences between the lower satellite pair being only 0.12 nT.

  12. Field-aligned currents and large scale magnetospheric electric fields

    NASA Technical Reports Server (NTRS)

    Dangelo, N.

    1980-01-01

    D'Angelo's model of polar cap electric fields (1977) was used to visualize how high-latitude field-aligned currents are driven by the solar wind generator. The region 1 and region 2 currents of Iijima and Potemra (1976) and the cusp field-aligned currents of Wilhjelm et al. (1978) and McDiarmid et al. (1978) are apparently driven by different generators, although in both cases the solar wind is their ultimate source.

  13. Radiofrequency fields and teratogenesis.

    PubMed

    Heynick, Louis N; Merritt, James H

    2003-01-01

    Experimental studies that sought teratologic effects or developmental abnormalities from exposure to radiofrequency electromagnetic fields (RFEMF) in the range 3 kHz-300 GHz are critically reviewed for their possible consequences on human health. Those studies were conducted on beetles, birds, rodents, and nonhuman primates. Collectively, those experimental studies indicate that teratologic effects can occur only from exposure levels that cause biologically detrimental increases in body temperature. No reliable experimental evidence was found for nonthermal teratologic effects; rodents, mouse fetuses, and perinatal mice are more susceptible to such effects than rats. The primary confirmed effect in rats at high RFEMF levels was initial weight deficits in fetuses and neonates that decreased with infant growth. More generally from findings with pregnant mammals, exposures at RFEMF levels far higher than those permitted under the IEEE human exposure guidelines are necessary to reach or exceed cited experimental thresholds for maternal temperature increases. Some results indicated that the levels necessary to cause such effects in pregnant mammals could exceed those lethal to the dams. In a behavioral study of squirrel monkeys, no effects were observed on usual dam-offspring interactions or EEGs, but unexpected deaths of a number of offspring had occurred. However, this finding was not confirmed in a study solely on infant death using a larger number of subjects for greater statistical validity. Also reviewed were epidemiologic studies of various human populations considered to have been chronically exposed to environmental levels of RFEMF. Early studies on the incidence of congenital anomalies yielded no credible evidence that chronic exposure of pregnant women or of fathers exposed to RFEMF from nearby sources at levels below those guidelines would cause any anomalies in their offspring. The findings of studies on pregnancy outcomes of female physiotherapists

  14. Field Science--the Nature and Utility of Scientific Fields.

    PubMed

    Casadevall, Arturo; Fang, Ferric C

    2015-09-08

    Fields are the fundamental sociological units of science. Despite their importance, relatively little has been written about their emergence, composition, structure, and function in the scientific enterprise. This essay considers the nature of fields and their important role in maintaining information and providing normative standards for scientific work. We suggest that fields arise naturally as a consequence of increasing information and scientific specialization. New fields tend to emerge as research communities grow, which may reflect biologically determined optima for the size of human groups. The benefits of fields include the organization of scientists with similar interests into communities that collectively define the next important problems to pursue. In the discipline of microbiology, fields are often organized on the basis of phylogenetic differences between microorganisms being studied. Although fields are essential to the proper functioning of science, their emergence can restrict access by outsiders and sustain dogmas that hinder progress. We suggest mechanisms to improve the functioning of scientific fields and to promote interdisciplinary interaction between fields.

  15. The field lines of an axisymmetric magnetic field

    NASA Technical Reports Server (NTRS)

    Backus, George E.

    1988-01-01

    The equations of Willis and Young (1987) for the field lines of an arbitrary axisymmetric multipole are generalized to an arbitrary linear combination of multipoles, i.e., to an arbitrary axisymmetric magnetic field B outside a sphere of radius a, S(a), centered on the origin, and containing all the sources of B. For this field, axisymmetric Stokes stream function is expressed in terms of the Gauss coefficients. It is shown that if only one Gauss coefficient is nonzero, the field line equations are identical to those obtained by Willis and Young.

  16. Field Science—the Nature and Utility of Scientific Fields

    PubMed Central

    Fang, Ferric C.

    2015-01-01

    ABSTRACT Fields are the fundamental sociological units of science. Despite their importance, relatively little has been written about their emergence, composition, structure, and function in the scientific enterprise. This essay considers the nature of fields and their important role in maintaining information and providing normative standards for scientific work. We suggest that fields arise naturally as a consequence of increasing information and scientific specialization. New fields tend to emerge as research communities grow, which may reflect biologically determined optima for the size of human groups. The benefits of fields include the organization of scientists with similar interests into communities that collectively define the next important problems to pursue. In the discipline of microbiology, fields are often organized on the basis of phylogenetic differences between microorganisms being studied. Although fields are essential to the proper functioning of science, their emergence can restrict access by outsiders and sustain dogmas that hinder progress. We suggest mechanisms to improve the functioning of scientific fields and to promote interdisciplinary interaction between fields. PMID:26350968

  17. Poloidal and toroidal fields in geomagnetic field modeling

    NASA Astrophysics Data System (ADS)

    Backus, G.

    1986-02-01

    The application of surface operator theory to poloidal and toroidal fields in geomagnetic field modeling is described. Surface operators are obtained for the dimensionless surface gradient; the dimensionless surface curl; the dimensionless surface Laplacian, as well as for the Funk-Hecke operators, integral operators, and axisymmetric kernels. Methods are given for interpreting satellite measurements of the geomagnetic field B, assuming B is can vary significantly and rapidly with time, and there are electric fields in the sample. Approximation schemes for ionospheric currents are also described.

  18. Geothermal field's interaction with geophysical fields of another nature

    SciTech Connect

    Novik, Oleg B.; Mikhailovskaya, Irina B.; Repin, Dmitry G.; Yershov, Sergey V.

    1996-01-24

    The energy balance of active lithosphere zones is to a large extent determined by nonstationary interaction of mechanical (elastic and hydrodynamic), thermal, electromagnetic, and gravitational geophysical fields. Seismic disturbances of electromagnetic and temperature fields, repeatedly observed before earthquakes are a striking manifestation of this interaction (Sec. 1). Technological processes of exploitation of hydrothermal deposits are determined by the interaction of hydrodynamical and temperature field (Sec. 2). These “fast” interactions (with the characteristic time scale from seconds to years) take place against the background of “slow” thermomechanical interactions (time scale of Myears), the latter determining the formation of regional geothermal fields (Sec. 3).

  19. Magnetic fields around evolved stars

    NASA Astrophysics Data System (ADS)

    Leal-Ferreira, M.; Vlemmings, W.; Kemball, A.; Amiri, N.; Maercker, M.; Ramstedt, S.; Olofsson, G.

    2014-04-01

    A number of mechanisms, such as magnetic fields, (binary) companions and circumstellar disks have been suggested to be the cause of non-spherical PNe and in particular collimated outflows. This work investigates one of these mechanisms: the magnetic fields. While MHD simulations show that the fields can indeed be important, few observations of magnetic fields have been done so far. We used the VLBA to observe five evolved stars, with the goal of detecting the magnetic field by means of water maser polarization. The sample consists in four AGB stars (IK Tau, RT Vir, IRC+60370 and AP Lyn) and one pPN (OH231.8+4.2). In four of the five sources, several strong maser features were detected allowing us to measure the linear and/or circular polarization. Based on the circular polarization detections, we infer the strength of the component of the field along the line of sight to be between ~30 mG and ~330 mG in the water maser regions of these four sources. When extrapolated to the surface of the stars, the magnetic field strength would be between a few hundred mG and a few Gauss when assuming a toroidal field geometry and higher when assuming more complex magnetic fields. We conclude that the magnetic energy we derived in the water maser regions is higher than the thermal and kinetic energy, leading to the conclusion that, indeed, magnetic fields probably play an important role in shaping Planetary Nebulae.

  20. Construction of surface pressure field from scatterometer wind field

    NASA Technical Reports Server (NTRS)

    Wurtele, Morton G.; Hsu, Carol H.; Cunningham, Glen F.; Woiceshyn, Peter M.

    1989-01-01

    An account of the construction of surface pressure fields from Seasat-A satellite scatterometer (SASS) winds as carried out by different methods, and the comparison of these pressure fields with those derived from in situ ship observations is presented. On the assumption that the pressure adjusts itself instantaneously to the motion field, it may be computed by various methods. One of these makes use of planetary boundary theory, and of the possible techniques in this category a two-layer iterative scheme admitting of the parametrization of diabatic and baroclinic effects and of secondary flow was chosen. A second method involves the assumption of zero two-dimensional divergence, leading to a Laplace's equation (the balance equation) in pressure, with the wind field serving as a forcing function. This method does not accommodate adiabatic or baroclinic effects, and requires a knowledge of the pressure at all boundary points. Two comparison fields are used for validation: the conventional operational analyses of the US National Meteorological Center (NMC), and the special analyses of the Gulf of Alaska Experiment (GOASEX), which were done by hand. The results of the computations were as follows: (1) The pressure fields, as computed from the SASS winds alone, closely approximated the NMC fields in regions where reasonable in situ coverage was available (typically, one or two mb differences over most of the chart, three to four mb in extreme cases); (2) In some cases the SASS-derived pressure fields displayed high-resolution phenomena not detected by the NMC fields, but evident in the GOASEX data; and, (3) As expected, the pressure fields derived from the balance equation were much smoother and less well resolved than the SASS-derived or NMC fields. The divergence as measured from the SASS winds is smaller than, but of the same order of magnitude as, the vorticity.

  1. Field-structured composite studies.

    SciTech Connect

    Martin, James Ellis; Williamson, Rodney L.

    2004-04-01

    Field-structured composites (FSCs) were produced by hosting micron-sized gold-coated nickel particles in a pre-polymer and allowing the mixture to cure in a magnetic field environment. The feasibility of controlling a composite's electrical conductivity using feedback control applied to the field coils was investigated. It was discovered that conductivity in FSCs is primarily determined by stresses in the polymer host matrix due to cure shrinkage. Thus, in cases where the structuring field was uniform and unidirectional so as to produce chainlike structures in the composite, no electrical conductivity was measured until well after the structuring field was turned off at the gel point. In situations where complex, rotating fields were used to generate complex, three-dimensional structures in a composite, very small, but measurable, conductivity was observed prior to the gel point. Responsive, sensitive prototype chemical sensors were developed based on this technology with initial tests showing very promising results.

  2. Magnetic fields from phase transitions

    NASA Astrophysics Data System (ADS)

    Hindmarsh, Mark; Everett, Allen

    1998-11-01

    The generation of primordial magnetic fields from cosmological phase transitions is discussed, paying particular attention to the electroweak transition and to the various definitions of the ``average'' field that have been put forward. It is emphasized that only the volume average has dynamical significance as a seed for galactic dynamos. On rather general grounds of causality and energy conservation, it is shown that, in the absence of MHD effects that transfer power in the magnetic field from small to large scales, processes occurring at the electroweak transition cannot generate fields stronger than 10-20 G on a scale of 0.5 Mpc. However, it is implausible that this upper bound could ever be reached, as it would require all the energy in the Universe to be turned into a magnetic field coherent at the horizon scale. Non-linear MHD effects seem therefore to be necessary if the electroweak transition is to create a primordial seed field.

  3. NMR at very low fields.

    PubMed

    Trahms, Lutz; Burghoff, Martin

    2010-10-01

    Although nuclear magnetic resonance in low fields around or below the Earth's magnetic field is almost as old as nuclear magnetic resonance itself, the recent years have experienced a revival of this technique that is opposed to the common trend towards higher and higher fields. The background of this development is the expectation that the low-field domain may open a new window for the study of molecular structure and dynamics. Here, we will give an overview on the specific features in the low-field domain, both from the technical and from the physical point of view. In addition, we present a short passage on the option of magnetic resonance imaging in fields of the micro-Tesla range.

  4. Magnetic fields in the sun

    NASA Technical Reports Server (NTRS)

    Mullan, D. J.

    1974-01-01

    The observed properties of solar magnetic fields are reviewed, with particular reference to the complexities imposed on the field by motions of the highly conducting gas. Turbulent interactions between gas and field lead to heating or cooling of the gas according to whether the field energy density is less or greater than the maximum kinetic energy density in the convection zone. The field strength above which cooling sets in is 700 gauss. A weak solar dipole field may be primeval, but dynamo action is also important in generating new flux. The dynamo is probably not confined to the convection zone, but extends throughout most of the volume of the sun. Planetary tides appear to play a role in driving the dynamo.

  5. Acoustic field modulation in regenerators

    NASA Astrophysics Data System (ADS)

    Hu, J. Y.; Wang, W.; Luo, E. C.; Chen, Y. Y.

    2016-12-01

    The regenerator is a key component that transfers energy between heat and work. The conversion efficiency is significantly influenced by the acoustic field in the regenerator. Much effort has been spent to quantitatively determine this influence, but few comprehensive experimental verifications have been performed because of difficulties in modulating and measuring the acoustic field. In this paper, a method requiring two compressors is introduced and theoretically investigated that achieves acoustic field modulation in the regenerator. One compressor outputs the acoustic power for the regenerator; the other acts as a phase shifter. A RC load dissipates the acoustic power out of both the regenerator and the latter compressor. The acoustic field can be modulated by adjusting the current in the two compressors and opening the RC load. The acoustic field is measured with pressure sensors instead of flow-field imaging equipment, thereby greatly simplifying the experiment.

  6. Agricultural fields, Khartoum, Sudan, Africa

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This herringbone pattern of irrigated agricultural fields near Khartoum, Sudan (14.5N, 33.5E) is very distinctive in both size and shape. The region contains thousands of these rectangular fields bounded by canals which carry water from both the White and Blue Nile Rivers. A crop rotation system is used so that some fields are in cotton, millit, sorghum or fallow to conserve moisture and control weeds and insects. See also STS049-96-003.

  7. Lectures on Matrix Field Theory

    NASA Astrophysics Data System (ADS)

    Ydri, Badis

    The subject of matrix field theory involves matrix models, noncommutative geometry, fuzzy physics and noncommutative field theory and their interplay. In these lectures, a lot of emphasis is placed on the matrix formulation of noncommutative and fuzzy spaces, and on the non-perturbative treatment of the corresponding field theories. In particular, the phase structure of noncommutative $\\phi^4$ theory is treated in great detail, and an introduction to noncommutative gauge theory is given.

  8. Noncommutativity and scalar field cosmology

    SciTech Connect

    Guzman, W.; Sabido, M.; Socorro, J.

    2007-10-15

    In this work we extend and apply a previous proposal to study noncommutative cosmology to the Friedmann-Robertson-Walker cosmological background coupled to a scalar field. This is done in classical and quantum scenarios. In both cases noncommutativity is introduced in the gravitational field as well as in the scalar field through a deformation of minisuperspace, and we are able to find exact solutions. Finally, the effects of noncommutativity on the classical evolution are analyzed.

  9. Field theory and particle physics

    SciTech Connect

    Eboli, O.J.P.; Gomes, M.; Santoro, A.

    1990-01-01

    This book contains the proceedings of the topics covered during the fifth Jorge Andre Swieca Summer School. The first part of the book collects the material devoted to quantum field theory. There were four courses on methods in Field Theory; H. O. Girotti lectured on constrained dynamics, R. Jackiw on the Schrodinger representation in Field Theory, S.-Y. Pi on the application of this representation to quantum fields in a Robertson-Walker spacetime, and L. Vinet on Berry Connections. There were three courses on Conformal Field Theory: I. Todorov focused on the problem of construction and classification of conformal field theories. Lattice models, two-dimensional S matrices and conformal field theory were looked from the unifying perspective of the Yang-Baxter algebras in the lectures given by M. Karowski. Parasupersymmetric quantum mechanics was discussed in the lectures by L. Vinet. Besides those courses, there was an introduction to string field theory given by G. Horowitz. There were also three seminars: F. Schaposnik reported on recent applications of topological methods in field theory, P. Gerbert gave a seminar on three dimensional gravity and V. Kurak talked on two dimensional parafermionic models. The second part of this proceedings is devoted to phenomenology. There were three courses on Particle Physics: Dan Green lectured on collider physics, E. Predrazzi on strong interactions and G. Cohen-Tanoudji on the use of strings in strong interactions.

  10. Electrochemical formation of field emitters

    DOEpatents

    Bernhardt, Anthony F.

    1999-01-01

    Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area.

  11. Measurement of Helmholtz wave fields

    PubMed

    Alonso

    2000-07-01

    A simple formalism is found for the measurement of wave fields that satisfy the Helmholtz equation in free space. This formalism turns out to be analogous to the well-known theory of measurements for quantum-mechanical wave functions: A measurement corresponds to the squared magnitude of the inner product (in a suitable Hilbert space) of the wave field and a field that is associated with the detector. The measurement can also be expressed as an overlap in phase space of a special form of the Wigner function that is tailored for Helmholtz wave fields.

  12. Field Surveys of Amphibian Populations.

    ERIC Educational Resources Information Center

    Brodman, Robert

    2000-01-01

    Describes a course on amphibian research for environmental science majors. Involves students in field studies and introduces them to investigative research. Evaluates the course. (Contains 19 references.) (YDS)

  13. Volumetric Light-Field Excitation

    PubMed Central

    Schedl, David C.; Bimber, Oliver

    2016-01-01

    We explain how to concentrate light simultaneously at multiple selected volumetric positions by means of a 4D illumination light field. First, to select target objects, a 4D imaging light field is captured. A light field mask is then computed automatically for this selection to avoid illumination of the remaining areas. With one-photon illumination, simultaneous generation of complex volumetric light patterns becomes possible. As a full light-field can be captured and projected simultaneously at the desired exposure and excitation times, short readout and lighting durations are supported. PMID:27363565

  14. Multiple fields in stochastic inflation

    SciTech Connect

    Assadullahi, Hooshyar; Firouzjahi, Hassan; Noorbala, Mahdiyar; Vennin, Vincent; Wands, David

    2016-06-24

    Stochastic effects in multi-field inflationary scenarios are investigated. A hierarchy of diffusion equations is derived, the solutions of which yield moments of the numbers of inflationary e-folds. Solving the resulting partial differential equations in multi-dimensional field space is more challenging than the single-field case. A few tractable examples are discussed, which show that the number of fields is, in general, a critical parameter. When more than two fields are present for instance, the probability to explore arbitrarily large-field regions of the potential, otherwise inaccessible to single-field dynamics, becomes non-zero. In some configurations, this gives rise to an infinite mean number of e-folds, regardless of the initial conditions. Another difference with respect to single-field scenarios is that multi-field stochastic effects can be large even at sub-Planckian energy. This opens interesting new possibilities for probing quantum effects in inflationary dynamics, since the moments of the numbers of e-folds can be used to calculate the distribution of primordial density perturbations in the stochastic-δN formalism.

  15. Quantum field theory of fluids.

    PubMed

    Gripaios, Ben; Sutherland, Dave

    2015-02-20

    The quantum theory of fields is largely based on studying perturbations around noninteracting, or free, field theories, which correspond to a collection of quantum-mechanical harmonic oscillators. The quantum theory of an ordinary fluid is "freer", in the sense that the noninteracting theory also contains an infinite collection of quantum-mechanical free particles, corresponding to vortex modes. By computing a variety of correlation functions at tree and loop level, we give evidence that a quantum perfect fluid can be consistently formulated as a low-energy, effective field theory. We speculate that the quantum behavior is radically different from both classical fluids and quantum fields.

  16. The Nonlinear Field Space Theory

    NASA Astrophysics Data System (ADS)

    Mielczarek, Jakub; Trześniewski, Tomasz

    2016-08-01

    In recent years the idea that not only the configuration space of particles, i.e. spacetime, but also the corresponding momentum space may have nontrivial geometry has attracted significant attention, especially in the context of quantum gravity. The aim of this letter is to extend this concept to the domain of field theories, by introducing field spaces (i.e. phase spaces of field values) that are not affine spaces. After discussing the motivation and general aspects of our approach we present a detailed analysis of the prototype (quantum) Nonlinear Field Space Theory of a scalar field on the Minkowski background. We show that the nonlinear structure of a field space leads to numerous interesting predictions, including: non-locality, generalization of the uncertainty relations, algebra deformations, constraining of the maximal occupation number, shifting of the vacuum energy and renormalization of the charge and speed of propagation of field excitations. Furthermore, a compact field space is a natural way to implement the "Principle of finiteness" of physical theories, which once motivated the Born-Infeld theory. Thus the presented framework has a variety of potential applications in the theories of fundamental interactions (e.g. quantum gravity), as well as in condensed matter physics (e.g. continuous spin chains), and can shed new light on the issue of divergences in quantum field theories.

  17. Photospheric and coronal magnetic fields

    SciTech Connect

    Sheeley, N.R., Jr. )

    1991-01-01

    Research on small-scale and large-scale photospheric and coronal magnetic fields during 1987-1990 is reviewed, focusing on observational studies. Particular attention is given to the new techniques, which include the correlation tracking of granules, the use of highly Zeeman-sensitive infrared spectral lines and multiple lines to deduce small-scale field strength, the application of long integration times coupled with good seeing conditions to study weak fields, and the use of high-resolution CCD detectors together with computer image-processing techniques to obtain images with unsurpassed spatial resolution. Synoptic observations of large-scale fields during the sunspot cycle are also discussed. 101 refs.

  18. Electric Field Dependence of Photo-Induced Field Emission Current.

    NASA Astrophysics Data System (ADS)

    Egert, Charles Michael

    We have measured the photo-induced field emission current from a tungsten field emitter as a function of electric field. These experiments were performed with a retardation energy analyzer to measure total current and a 127(DEGREES) cylindrical differential energy analyzer to measure the energy resolved PFE current. The results of these experiments are compared with a simple theory of PFE, developed by Schwartz and Schaich, which is an extension of field emission theory including the surface photoeffect, but assuming constant photoexcitation matrix elements. Our experimental results disagree with this theory in two ways: First, for high fields and photon energy (electrons emitted above the field emission barrier maximum) theory predicts a larger increase in PFE current than is observed experimentally. Second, we have also confirmed the existence of a field dependent oscillatory component of the PFE current emitted from the W(110) surface with photon energies of 2.7 eV and 3.5 eV. The simple theory described here, as well as more sophisticated calculations, have been unable to explain this oscillatory feature. We have also reported, for the first time, the field dependence of the energy resolved PFE current measured with a 127(DEGREES) cylindrical energy analyzer. These preliminary results show evidence of the oscillatory component previously only observed in the total PFE current.

  19. Thomson scattering in a magnetic field. I - Field along z

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara A.

    1991-01-01

    The Monte Carlo method is used here to solve the radiative transfer equation for Thomson scattering in a constant magnetic field perpendicular to the atmosphere. Emergent radiation and polarization are presented for various atmospheric thicknesses. The circular polarization peaks at frequencies near the cyclotron, omega(c), and for propagation direction along the field. At low field strengths, the circular polarization is roughly proportional to omega(c)/omega; the linear polarization is proportional to the square of omega(c)/omega and the amount of circular polarization present at each scatter and is therefore much smaller than the circular polarization. The linear polarization is large for propagation direction perpendicular to the magnetic field and at frequencies near the cyclotron and in the strong-field limit. The position angle of the linear polarization undergoes a rotation of 90 deg at a value of omega(c)/omega near the square root of three.

  20. Inlet flow field investigation. Part 1: Transonic flow field survey

    NASA Technical Reports Server (NTRS)

    Yetter, J. A.; Salemann, V.; Sussman, M. B.

    1984-01-01

    A wind tunnel investigation was conducted to determine the local inlet flow field characteristics of an advanced tactical supersonic cruise airplane. A data base for the development and validation of analytical codes directed at the analysis of inlet flow fields for advanced supersonic airplanes was established. Testing was conducted at the NASA-Langley 16-foot Transonic Tunnel at freestream Mach numbers of 0.6 to 1.20 and angles of attack from 0.0 to 10.0 degrees. Inlet flow field surveys were made at locations representative of wing (upper and lower surface) and forebody mounted inlet concepts. Results are presented in the form of local inlet flow field angle of attack, sideflow angle, and Mach number contours. Wing surface pressure distributions supplement the flow field data.

  1. The MAVEN Magnetic Field Investigation

    NASA Astrophysics Data System (ADS)

    Connerney, J. E. P.; Espley, J.; Lawton, P.; Murphy, S.; Odom, J.; Oliversen, R.; Sheppard, D.

    2015-12-01

    The MAVEN magnetic field investigation is part of a comprehensive particles and fields subsystem that will measure the magnetic and electric fields and plasma environment of Mars and its interaction with the solar wind. The magnetic field instrumentation consists of two independent tri-axial fluxgate magnetometer sensors, remotely mounted at the outer extremity of the two solar arrays on small extensions ("boomlets"). The sensors are controlled by independent and functionally identical electronics assemblies that are integrated within the particles and fields subsystem and draw their power from redundant power supplies within that system. Each magnetometer measures the ambient vector magnetic field over a wide dynamic range (to 65,536 nT per axis) with a resolution of 0.008 nT in the most sensitive dynamic range and an accuracy of better than 0.05 %. Both magnetometers sample the ambient magnetic field at an intrinsic sample rate of 32 vector samples per second. Telemetry is transferred from each magnetometer to the particles and fields package once per second and subsequently passed to the spacecraft after some reformatting. The magnetic field data volume may be reduced by averaging and decimation, when necessary to meet telemetry allocations, and application of data compression, utilizing a lossless 8-bit differencing scheme. The MAVEN magnetic field experiment may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors and the MAVEN mission plan provides for occasional spacecraft maneuvers—multiple rotations about the spacecraft x and z axes—to characterize spacecraft fields and/or instrument offsets in flight.

  2. The MAVEN Magnetic Field Investigation

    NASA Technical Reports Server (NTRS)

    Connerney, J. E. P.; Espley, J.; Lawton, P.; Murphy, S.; Odom, J.; Oliversen, R.; Sheppard, D.

    2014-01-01

    The MAVEN magnetic field investigation is part of a comprehensive particles and fields subsystem that will measure the magnetic and electric fields and plasma environment of Mars and its interaction with the solar wind. The magnetic field instrumentation consists of two independent tri-axial fluxgate magnetometer sensors, remotely mounted at the outer extremity of the two solar arrays on small extensions ("boomlets"). The sensors are controlled by independent and functionally identical electronics assemblies that are integrated within the particles and fields subsystem and draw their power from redundant power supplies within that system. Each magnetometer measures the ambient vector magnetic field over a wide dynamic range (to 65,536 nT per axis) with a quantization uncertainty of 0.008 nT in the most sensitive dynamic range and an accuracy of better than 0.05%. Both magnetometers sample the ambient magnetic field at an intrinsic sample rate of 32 vector samples per second. Telemetry is transferred from each magnetometer to the particles and fields package once per second and subsequently passed to the spacecraft after some reformatting. The magnetic field data volume may be reduced by averaging and decimation, when necessary to meet telemetry allocations, and application of data compression, utilizing a lossless 8-bit differencing scheme. The MAVEN magnetic field experiment may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. A spacecraft magnetic control program was implemented to provide a magnetically clean environment for the magnetic sensors and the MAVEN mission plan provides for occasional spacecraft maneuvers - multiple rotations about the spacecraft x and z axes - to characterize spacecraft fields and/or instrument offsets in flight.

  3. Feynman's Proof and Non-Elastic Displacement Fields: Relationship Between Magnetic Field and Defects Field

    NASA Astrophysics Data System (ADS)

    Nakamura, Nozomu; Yamasaki, Kazuhito

    2016-12-01

    We consider the relationship between the magnetic field and the non-elastic displacement field including defects, from the viewpoints of non-commutativity of the positions and non-commutativity of the derivatives. The former non-commutativity is related to the magnetic field by Feynman's proof (1948), and the latter is related to the defect fields by the continuum theory of defects. We introduce the concept of differential geometry to the non-elastic displacement field and derive an extended relation that includes basic equations, such as Gauss's law for magnetism and the conservation law for dislocation density. The relation derived in this paper also extends the first Bianchi identity in linear approximation to include the effect of magnetism. These findings suggest that Feynman's approach with a non-elastic displacement field is useful for understanding the relationship between magnetism and non-elastic mechanics.

  4. Field Trips Within Easy Reach.

    ERIC Educational Resources Information Center

    Fitzsimmons, Charles P.

    1983-01-01

    Provides suggestions for conducting field trips at the local school site. Points of interest might include building materials, evidence of chemical/physical weathering, variations in soil type, changes in elevation on school ground, and others. Three simple field trips are described. (JN)

  5. Open string fields as matrices

    NASA Astrophysics Data System (ADS)

    Kishimoto, Isao; Masuda, Toru; Takahashi, Tomohiko; Takemoto, Shoko

    2015-03-01

    We show that the action expanded around Erler-Maccaferri's N D-brane solution describes the N+1 D-brane system where one D-brane disappears due to tachyon condensation. String fields on multi-branes can be regarded as block matrices of a string field on a single D-brane in the same way as matrix theories.

  6. Magnetic Fields: Visible and Permanent.

    ERIC Educational Resources Information Center

    Winkeljohn, Dorothy R.; Earl, Robert D.

    1983-01-01

    Children will be able to see the concept of a magnetic field translated into a visible reality using the simple method outlined. Standard shelf paper, magnets, iron filings, and paint in a spray can are used to prepare a permanent and well-detailed picture of the magnetic field. (Author/JN)

  7. Visual field defects in onchocerciasis.

    PubMed Central

    Thylefors, B; Tønjum, A M

    1978-01-01

    Lesions in the posterior segment of the eye in onchocerciasis may give visual field defects, but so far no detailed investigation has been done to determine the functional visual loss. Examination of the visual fields in 18 selected cases of onchocerciasis by means of a tangent screen test revealed important visual field defects associated with lesions in the posterior segment of the eye. Involvement of the optic nerve seemed to be important, giving rise to severely constricted visual fields. Cases of postneuritic optic atrophy showed a very uniform pattern of almost completely constricted visual fields, with only 5 to 10 degree central rest spared. Papillitis gave a similar severe constriction of the visual fields. The pattern of visual fields associated with optic neuropathy in onchocerciasis indicates that a progressive lesion of the optic nerve from the periphery may be responsible for the loss of vision. The visual field defects in onchocerciasis constitute a serious handicap, which must be taken into consideration when estimating the socioeconomic importance of the disease. Images PMID:678499

  8. Emerging Innovation: Allied Health Fields

    ERIC Educational Resources Information Center

    Lang, Janell B.

    2004-01-01

    This article takes a closer look at emerging fields in the allied health arena. The relatively new field of Health Information Technology is one of the exciting prospects, surging with growth opportunities. These individuals are medical language experts who interpret, process, store and retrieve health information for research and data collection.…

  9. Integrated flow field (IFF) structure

    NASA Technical Reports Server (NTRS)

    Pien, Shyhing M. (Inventor); Warshay, Marvin (Inventor)

    2012-01-01

    The present disclosure relates in part to a flow field structure comprising a hydrophilic part and a hydrophobic part communicably attached to each other via a connecting interface. The present disclosure further relates to electrochemical cells comprising the aforementioned flow fields.

  10. Research in particles and fields

    NASA Technical Reports Server (NTRS)

    Vogt, R. E.; Buffington, A.; Davis, L., Jr.; Stone, E. C.

    1980-01-01

    The astrophysical aspects of cosmic and gamma rays and the radiation environment of the Earth and other planets investigated by means of energetic particle detector systems flown on spacecraft and balloons are discussed. The theory of particles and fields in space is also addressed with particular emphasis on models of Saturn's magnetic field.

  11. Field measurements involve various techniques

    SciTech Connect

    Moore, D.P.; Byars, H.G. )

    1990-07-30

    A number of field techniques are available to determine the extent of corrosion on production equipment. This article on oil field corrosion explains the use of corrosion coupons, several types of probes, and various inspection techniques, and shows how to monitor iron content in water.

  12. Coding Major Fields of Study.

    ERIC Educational Resources Information Center

    Bobbitt, L. G.; Carroll, C. D.

    The National Center for Education Statistics conducts surveys which require the coding of the respondent's major field of study. This paper presents a new system for the coding of major field of study. It operates on-line i a Computer Assisted Telephone Interview (CATI) environment and allows conversational checks to verify coding directly from…

  13. Teaching Field Biology with Photography

    ERIC Educational Resources Information Center

    Jenkins, Ronald L.; Howell, W. Mike; Davenport, L. J.; Wood, Linda F.

    2003-01-01

    Photography makes an easy and excellent tool for teaching field biology courses, allowing students to study nature without harming it. This photographic technique is used in capturing images of vertebrates, invertebrates, and plants during class field trips, then making these images available for students to identify and study from a departmental…

  14. Youth Field Day Planning Guide.

    ERIC Educational Resources Information Center

    Wisconsin State Dept. of Natural Resources, Madison.

    Youth field days expose children to outdoor activities, land use ethics, and habitat conservation and encourage adults to be mentors in these areas. A typical youth field day could have programs in archery, fishing, boating, shooting, or safety. The event requires a diverse steering committee that usually includes sporting clubs and state…

  15. Weed Identification Field Training Demonstrations.

    ERIC Educational Resources Information Center

    Murdock, Edward C.; And Others

    1986-01-01

    Reviews efforts undertaken in weed identification field training sessions for agriprofessionals in South Carolina. Data over a four year period (1980-1983) revealed that participants showed significant improvement in their ability to identify weeds. Reaffirms the value of the field demonstration technique. (ML)

  16. Fast superconducting magnetic field switch

    DOEpatents

    Goren, Yehuda; Mahale, Narayan K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

  17. Fast superconducting magnetic field switch

    DOEpatents

    Goren, Y.; Mahale, N.K.

    1996-08-06

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs.

  18. New Manning System Field Evaluation

    DTIC Science & Technology

    1986-03-01

    our Analytic hodel (see Chapter 5, New Manning Svestem Field Evaluacion . Technical Revore No. I, RAJL-, November c t, e number or soldiers retaking...and meaningful performance measures are not only crucial to the WRAIR N Field Evaluacion but also to the Army. To know which unit does betzer than

  19. Caution: Strong Gravitational Field Present

    ERIC Educational Resources Information Center

    Reif, Marc

    2014-01-01

    I came up with a new way to introduce the concept of a constant gravitational field near the surface of the Earth. I made "g-field detectors" (see Fig. 1 ) and suspended them by strings from the ceiling in a regular spacing. The detectors are cardstock arrows with a hole punched out of them and the letter "g" in the center.

  20. Pushing particles in extreme fields

    NASA Astrophysics Data System (ADS)

    Gordon, Daniel F.; Hafizi, Bahman; Palastro, John

    2017-03-01

    The update of the particle momentum in an electromagnetic simulation typically employs the Boris scheme, which has the advantage that the magnetic field strictly performs no work on the particle. In an extreme field, however, it is found that onerously small time steps are required to maintain accuracy. One reason for this is that the operator splitting scheme fails. In particular, even if the electric field impulse and magnetic field rotation are computed exactly, a large error remains. The problem can be analyzed for the case of constant, but arbitrarily polarized and independent electric and magnetic fields. The error can be expressed in terms of exponentials of nested commutators of the generators of boosts and rotations. To second order in the field, the Boris scheme causes the error to vanish, but to third order in the field, there is an error that has to be controlled by decreasing the time step. This paper introduces a scheme that avoids this problem entirely, while respecting the property that magnetic fields cannot change the particle energy.

  1. Field grading in capacitor margins

    NASA Astrophysics Data System (ADS)

    Springer, T. E.; Sarjeant, W. J.; Nunnally, W. C.

    1981-06-01

    Some of the results of modeling electric fields in the margin of a bogey plastic film liquid impregnant capacitor are presented where effects of foil edge shape, different impregnants, and grading wires are examined. It is concluded that placement tolerance and connection problems make grading wires impractical and that folded foil edges are still the best solution to field grading.

  2. Simultaneous particle and field observations of field-aligned currents

    NASA Technical Reports Server (NTRS)

    Berko, F. W.; Hoffman, R. A.; Burton, R. K.; Holzer, R. E.

    1973-01-01

    Simultaneous measurements of low energy precipitating electrons and magnetic fluctuations from the low altitude polar orbiting satellite OGO-4 have been compared. Analysis of the two sets of experimental data for isolated events led to the classification of high latitude field-aligned currents as purely temporal or purely spatial variations. Magnetic field disturbances calculated using these simple current models and the measured particle fluxes were in good agreement with measured field values. While fluxes of greater than 1 keV electrons are detected primarily on the nightside, magnetometer disturbances indicative of field-aligned currents were seen at all local times, both in the visual auroral regions and dayside polar cusp. Thus electrons with energies less than approximately 1 keV are the prime charge carriers in high latitude dayside field-aligned currents. The satellite measurements are in good agreement with previously measured field-aligned current values and with values predicted from several models involving magnetospheric field-aligned currents.

  3. Vestibular stimulation by magnetic fields

    PubMed Central

    Ward, Bryan K.; Roberts, Dale C.; Della Santina, Charles C.; Carey, John P.; Zee, David S.

    2015-01-01

    Individuals working next to strong static magnetic fields occasionally report disorientation and vertigo. With the increasing strength of magnetic fields used for magnetic resonance imaging (MRI) studies, these reports have become more common. It was recently learned that humans, mice and zebrafish all demonstrate behaviors consistent with constant peripheral vestibular stimulation while inside a strong, static magnetic field. The proposed mechanism for this effect involves a Lorentz force resulting from the interaction of a strong static magnetic field with naturally occurring ionic currents flowing through the inner ear endolymph into vestibular hair cells. The resulting force within the endolymph is strong enough to displace the lateral semicircular canal cupula, inducing vertigo and the horizontal nystagmus seen in normal mice and in humans. This review explores the evidence for interactions of magnetic fields with the vestibular system. PMID:25735662

  4. Carbon nanotubes as field emitter.

    PubMed

    Zou, Rujia; Hu, Junqing; Song, Yuelin; Wang, Na; Chen, Huihui; Chen, Haihua; Wu, Jianghong; Sun, Yangang; Chen, Zhigang

    2010-12-01

    Carbon nanotubes (CNTs) have recently emerged as a promising material of electron field emitters. They exhibit extraordinary field emission properties because of their high electrical conductivity, high aspect ratio "needle like" shape for optimum geometrical field enhancement, and remarkable thermal stability. In this Review, we emphasize the estimation and influencing factors of CNTs' emission properties, and discuss in detail the emission properties of macroscopic CNT cathodes, especially fabricated by transplant methods, and describe recent progress on understanding of CNT field emitters and analyze issues related to applications of CNT based cold cathodes in field emission display (FED). We foresee that CNT-FED will take an important place in display technologies in the near future.

  5. Are Field OB Stars Alone?

    NASA Astrophysics Data System (ADS)

    Oey, Sally

    2005-07-01

    This SNAP program offers an inexpensive, simple program to search for low-mass companions of field OB stars. Do field OB stars exist in true isolation, as suggested by a recent Galactic study, or are they the tip of the iceberg on a small cluster of low-mass stars as predicted by the cluster mass function and stellar IMF? Short ACS/WFC V and I observations proposed here may easily resolve this issue for field OB stars in the Small Magellanic Cloud. Truly isolated OB stars represent a theoretical challenge and variation from clusters, in mode of star formation, and have important consequences for our understanding of the field stellar population in galaxies. Small clusters around the field OB stars, on the other hand, may confirm the universality of the stellar clustering law and IMF.

  6. Compact orthogonal NMR field sensor

    DOEpatents

    Gerald, II, Rex E.; Rathke, Jerome W.

    2009-02-03

    A Compact Orthogonal Field Sensor for emitting two orthogonal electro-magnetic fields in a common space. More particularly, a replacement inductor for existing NMR (Nuclear Magnetic Resonance) sensors to allow for NMR imaging. The Compact Orthogonal Field Sensor has a conductive coil and a central conductor electrically connected in series. The central conductor is at least partially surrounded by the coil. The coil and central conductor are electrically or electro-magnetically connected to a device having a means for producing or inducing a current through the coil and central conductor. The Compact Orthogonal Field Sensor can be used in NMR imaging applications to determine the position and the associated NMR spectrum of a sample within the electro-magnetic field of the central conductor.

  7. Quantum oscillations without magnetic field

    NASA Astrophysics Data System (ADS)

    Liu, Tianyu; Pikulin, D. I.; Franz, M.

    2017-01-01

    When the magnetic field B is applied to a metal, nearly all observable quantities exhibit oscillations periodic in 1 /B . Such quantum oscillations reflect the fundamental reorganization of electron states into Landau levels as a canonical response of the metal to the applied magnetic field. We predict here that, remarkably, in the recently discovered Dirac and Weyl semimetals, quantum oscillations can occur in the complete absence of magnetic field. These zero-field quantum oscillations are driven by elastic strain which, in the space of the low-energy Dirac fermions, acts as a chiral gauge potential. We propose an experimental setup in which the strain in a thin film (or nanowire) can generate a pseudomagnetic field b as large as 15 T and demonstrate the resulting de Haas-van Alphen and Shubnikov-de Haas oscillations periodic in 1 /b .

  8. Preflare magnetic and velocity fields

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J.; Gaizauskas, V.; Chapman, G. A.; Deloach, A. C.; Gary, G. A.; Jones, H. P.; Karpen, J. T.; Martres, M.-J.; Porter, J. G.; Schmeider, B.

    1986-01-01

    A characterization is given of the preflare magnetic field, using theoretical models of force free fields together with observed field structure to determine the general morphology. Direct observational evidence for sheared magnetic fields is presented. The role of this magnetic shear in the flare process is considered within the context of a MHD model that describes the buildup of magnetic energy, and the concept of a critical value of shear is explored. The related subject of electric currents in the preflare state is discussed next, with emphasis on new insights provided by direct calculations of the vertical electric current density from vector magnetograph data and on the role of these currents in producing preflare brightenings. Results from investigations concerning velocity fields in flaring active regions, describing observations and analyses of preflare ejecta, sheared velocities, and vortical motions near flaring sites are given. This is followed by a critical review of prevalent concepts concerning the association of flux emergence with flares

  9. Multipole expansions and intense fields

    NASA Astrophysics Data System (ADS)

    Reiss, Howard R.

    1984-02-01

    In the context of two-body bound-state systems subjected to a plane-wave electromagnetic field, it is shown that high field intensity introduces a distinction between long-wavelength approximation and electric dipole approximation. This distinction is gauge dependent, since it is absent in Coulomb gauge, whereas in "completed" gauges of Göppert-Mayer type the presence of high field intensity makes electric quadrupole and magnetic dipole terms of importance equal to electric dipole at long wavelengths. Another consequence of high field intensity is that multipole expansions lose their utility in view of the equivalent importance of a number of low-order multipole terms and the appearance of large-magnitude terms which defy multipole categorization. This loss of the multipole expansion is gauge independent. Also gauge independent is another related consequence of high field intensity, which is the intimate coupling of center-of-mass and relative coordinate motions in a two-body system.

  10. Ground vortex flow field investigation

    NASA Technical Reports Server (NTRS)

    Kuhn, Richard E.; Delfrate, John H.; Eshleman, James E.

    1988-01-01

    Flow field investigations were conducted at the NASA Ames-Dryden Flow Visualization Facility (water tunnel) to investigate the ground effect produced by the impingement of jets from aircraft nozzles on a ground board in a STOL operation. Effects on the overall flow field with both a stationary and a moving ground board were photographed and compared with similar data found in other references. Nozzle jet impingement angles, nozzle and inlet interaction, side-by-side nozzles, nozzles in tandem, and nozzles and inlets mounted on a flat plate model were investigated. Results show that the wall jet that generates the ground effect is unsteady and the boundary between the ground vortex flow field and the free-stream flow is unsteady. Additionally, the forward projection of the ground vortex flow field with a moving ground board is one-third less than that measured over a fixed ground board. Results also showed that inlets did not alter the ground vortex flow field.

  11. Error Field Correction in ITER

    SciTech Connect

    Park, Jong-kyu; Boozer, Allen H.; Menard, Jonathan E.; Schaffer, Michael J.

    2008-05-22

    A new method for correcting magnetic field errors in the ITER tokamak is developed using the Ideal Perturbed Equilibrium Code (IPEC). The dominant external magnetic field for driving islands is shown to be localized to the outboard midplane for three ITER equilibria that represent the projected range of operational scenarios. The coupling matrices between the poloidal harmonics of the external magnetic perturbations and the resonant fields on the rational surfaces that drive islands are combined for different equilibria and used to determine an ordered list of the dominant errors in the external magnetic field. It is found that efficient and robust error field correction is possible with a fixed setting of the correction currents relative to the currents in the main coils across the range of ITER operating scenarios that was considered.

  12. TRANSDUCER FIELD IMAGING USING ACOUSTOGRAPHY

    PubMed Central

    Sandhu, Jaswinder S.; Schoonover, Robert W.; Weber, Joshua I.; Tawiah, J.; Kunin, Vitaliy; Anastasio, Mark A.

    2013-01-01

    A common current practice for transducer field mapping is to scan, point-by-point, a hydrophone element in a 2D raster at various distances from the transducer radiating surface. This approach is tedious, requiring hours of scanning time to generate full cross-sectional and/or axial field distributions. Moreover, the lateral resolution of the field distribution image is dependent on the indexing steps between data points. Acoustography is an imaging process in which an acousto-optical (AO) area sensor is employed to record the intensity of an ultrasound wavefield on a two-dimensional plane. This paper reports on the application of acoustography as a simple but practical method for assessing transducer field characteristics. A case study performed on a commercial transducer is reported, where the radiated fields are imaged using acoustography and compared to the corresponding quantities that are predicted numerically. PMID:23967016

  13. PYROTRON WITH TRANSLATIONAL CLOSURE FIELDS

    DOEpatents

    Hartwig, E.C.; Cummings, D.B.; Post, R.F.

    1962-01-01

    Circuit means is described for effecting inward transla- ' tory motion of the intensified terminal reflector field regions of a magnetic mirror plasma containment field with a simultaneous intensification of the over-all field configuration. The circuit includes a segmented magnetic field generating solenoid and sequentially actuated switch means to consecutively short-circuit the solenoid segments and place charged capacitor banks in shunt with the segments in an appropriate correlated sequence such that electrical energy is transferred inwardly between adjacent segments from the opposite ends of the solenoid. The resulting magnetic field is effective in both radially and axially adiabatically compressing a plasma in a reaction chamber disposed concentrically within the solenoid. In addition, one half of the circuit may be employed to unidirectionally accelerate plasma. (AEC)

  14. Electromagnetic fields and public health.

    PubMed Central

    Aldrich, T E; Easterly, C E

    1987-01-01

    A review of the literature is provided for the topic of health-related research and power frequency electromagnetic fields. Minimal evidence for concern is present on the basis of animal and plant research. General observation would accord with the implication that there is no single and manifest health effect as the result of exposure to these fields. There are persistent indications, however, that these fields have biologic activity, and consequently, there may be a deleterious component to their action, possibly in the presence of other factors. Power frequency electromagnetic field exposures are essentially ubiquitous in modern society, and their implications in the larger perspective of public health are unclear at this time. Electromagnetic fields represent a methodological obstacle for epidemiologic studies and a quandary for risk assessment; there is need for more data. PMID:3319560

  15. Shaping the nonlinear near field

    PubMed Central

    Wolf, Daniela; Schumacher, Thorsten; Lippitz, Markus

    2016-01-01

    Light scattering at plasmonic nanoparticles and their assemblies has led to a wealth of applications in metamaterials and nano-optics. Although shaping of fields around nanostructures is widely studied, the influence of the field inside the nanostructures is often overlooked. The linear field distribution inside the structure taken to the third power causes third-harmonic generation, a nonlinear optical response of matter. Here we demonstrate by a far field Fourier imaging method how this simple fact can be used to shape complex fields around a single particle alone. We employ this scheme to switch the third-harmonic emission from a single point source to two spatially separated but coherent sources, as in Young's double-slit assembly. We envision applications as diverse as coherently feeding antenna arrays and optical spectroscopy of spatially extended electronic states. PMID:26762487

  16. Double field theory inspired cosmology

    SciTech Connect

    Wu, Houwen; Yang, Haitang E-mail: hyanga@scu.edu.cn

    2014-07-01

    Double field theory proposes a generalized spacetime action possessing manifest T-duality on the level of component fields. We calculate the cosmological solutions of double field theory with vanishing Kalb-Ramond field. It turns out that double field theory provides a more consistent way to construct cosmological solutions than the standard string cosmology. We construct solutions for vanishing and non-vanishing symmetry preserving dilaton potentials. The solutions assemble the pre- and post-big bang evolutions in one single line element. Our results show a smooth evolution from an anisotropic early stage to an isotropic phase without any special initial conditions in contrast to previous models. In addition, we demonstrate that the contraction of the dual space automatically leads to both an inflation phase and a decelerated expansion of the ordinary space during different evolution stages.

  17. Reversed field pinch current drive with oscillating helical fields

    SciTech Connect

    Farengo, Ricardo; Clemente, Roberto Antonio

    2006-04-15

    The use of oscillating helical magnetic fields to produce and sustain the toroidal and poloidal currents in a reversed field pinch (RFP) is investigated. A simple physical model that assumes fixed ions, massless electrons, and uniform density and resistivity is employed. Thermal effects are neglected in Ohm's law and helical coordinates are introduced to reduce the number of coupled nonlinear equations that must be advanced in time. The results show that it is possible to produce RFP-like magnetic field profiles with pinch parameters close to the experimental values. The efficiencies obtained for moderate resistivity, and the observed scaling, indicate that this could be a very attractive method for high temperature plasmas.

  18. Field-aligned currents and ionospheric electric fields

    NASA Technical Reports Server (NTRS)

    Yasuhara, F.; Akasofu, S.-I.

    1977-01-01

    It is shown that the observed distribution of the ionospheric electric field can be deduced from an equation combining Ohm's law with the current continuity equation by using the 'observed' distribution of field-aligned currents as the boundary condition for two models of the ionosphere. The first model has one conductive annular ring representing the quiet-time auroral precipitation belt; the second has two conductive annular rings that simulate the discrete and diffuse auroral regions. An analysis is performed to determine how well the electric-field distribution can be reproduced. The results indicate that the first model reproduces the Sq(p)-type distribution, the second model reproduces reasonably well a substorm-type potential and ionospheric current patterns together with the Harang discontinuity, and that the distribution of field-aligned currents is the same for both models.

  19. An overview of craniospinal axis fields and field matching

    SciTech Connect

    Scott, Robin L.

    2013-01-01

    Many methods are implemented for craniospinal axis (CSA) radiation treatment (RT). This paper’s goal is to define correctly matched CSA RT fields. Overlap or a space between matched RT fields can create variances of dose and the possibility of negative side effects or disease recurrence, respectively. An accurate CSA RT match procedure is created with localization markers, immobilization devices, equations, feathered matches, safety gap, and portal imaging. A CS match angle is predetermined to optimize patient position before immobilization device fabrication. Various central axis (CA) placements within the brain and spine fields that effect gantry, table, and collimator rotation are described. An overview of the methods used to create CSA RT fields and matches is presented for optimal CSA RT implementation. In addition, to the author’s knowledge, this is the first time that a prone CSA RT with anesthesia has been described.

  20. History of the geomagnetic field

    USGS Publications Warehouse

    Doell, Richard R.

    1969-01-01

    Direct measurements of the direction and strength of the earth's magnetic field have provided a knowledge of the field's form and behavior during the last few hundreds of years. For older times, however, it has been necessary to measure the magnetism of certain rocks to learn what the geomagnetic field was like. For example, when a lava flow solidifies (at temperatures near 1000??C) and cools through the Curie point of the magnetic minerals contained in it (around 500??C) it acquires a remanent magnetism that is (1) very weak, (2) very stablel, (3) paralle to the direction of the ambient geomagnetic field, and (4) proportional in intensity to the ambient field. Separating, by various analytical means, this magnetization from other 'unwanted' magnetizations has allowed paleomagnetists to study the historical and prehistorical behavior of the earth's field. It has been learned, for example, that the strength of the field was almost twice its present value 2000 years ago and that it has often completely reversed its polarity. Paleo-magnetists have also confirmed that most oceans are, geologically speaking, relatively new features, and that the continents have markedly changed their positions over the surface of the earth. ?? 1969 The American Institute of Physics.

  1. Strong-field atomic ionization in an elliptically polarized laser field and a constant magnetic field

    NASA Astrophysics Data System (ADS)

    Rylyuk, V. M.

    2016-05-01

    Within the framework of the quasistationary quasienergy state (QQES) formalism, the tunneling and multiphoton ionization of atoms and ions subjected to a perturbation by a high intense laser radiation field of an arbitrary polarization and a constant magnetic field are considered. On the basis of the exact solution of the Schrödinger equation and the Green's function for the electron moving in an arbitrary laser field and crossed constant electric and magnetic fields, the integral equation for the complex quasienergy and the energy spectrum of the ejected electron are derived. Using the "imaginary-time" method, the extremal subbarrier trajectory of the photoelectron moving in a nonstationary laser field and a constant magnetic field are considered. Within the framework of the QQES formalism and the quasiclassical perturbation theory, ionization rates when the Coulomb interaction of the photoelectron with the parent ion is taken into account at arbitrary values of the Keldysh parameter are derived. The high accuracy of rates is confirmed by comparison with the results of numerical calculations. Simple analytical expressions for the ionization rate with the Coulomb correction in the tunneling and multiphoton regimes in the case of an elliptically polarized laser beam propagating at an arbitrary angle to the constant magnetic field are derived and discussed. The limits of small and large magnetic fields and low and high frequency of a laser field are considered in details. It is shown that in the presence of a nonstationary laser field perturbation, the constant magnetic field may either decrease or increase the ionization rate. The analytical consideration and numerical calculations also showed that the difference between the ionization rates for an s electron in the case of right- and left-elliptically polarized laser fields is especially significant in the multiphoton regime for not-too-high magnetic fields and decreases as the magnetic field increases. The paper

  2. MAGNETIC FIELD MEASUREMENTS FOR FAST-CHANGING MAGNETIC FIELDS.

    SciTech Connect

    JAIN, A.; ESCALLIER, J.; GANETIS, G.; LOUIE, W.; MARONE, A.; THOMAS. R.; WANDERER, P.

    2004-10-03

    Several recent applications for fast ramped magnets have been found that require rapid measurement of the field quality during the ramp. (In one instance, accelerator dipoles will be ramped at 1 T/sec, with measurements needed to the accuracy typically required for accelerators.) We have built and tested a new type of magnetic field measuring system to meet this need. The system consists of 16 stationary pickup windings mounted on a cylinder. The signals induced in the windings in a changing magnetic field are sampled and analyzed to obtain the field harmonics. To minimize costs, printed circuit boards were used for the pickup windings and a combination of amplifiers and ADPs used for the voltage readout system. New software was developed for the analysis. Magnetic field measurements of a model dipole developed for the SIS200 accelerator at GSI are presented. The measurements are needed to insure that eddy currents induced by the fast ramps do not impact the field quality needed for successful accelerator operation.

  3. Aircraft electric field measurements: Calibration and ambient field retrieval

    NASA Technical Reports Server (NTRS)

    Koshak, William J.; Bailey, Jeff; Christian, Hugh J.; Mach, Douglas M.

    1994-01-01

    An aircraft locally distorts the ambient thundercloud electric field. In order to determine the field in the absence of the aircraft, an aircraft calibration is required. In this work a matrix inversion method is introduced for calibrating an aircraft equipped with four or more electric field sensors and a high-voltage corona point that is capable of charging the aircraft. An analytic, closed form solution for the estimate of a (3 x 3) aircraft calibration matrix is derived, and an absolute calibration experiment is used to improve the relative magnitudes of the elements of this matrix. To demonstrate the calibration procedure, we analyze actual calibration date derived from a Lear jet 28/29 that was equipped with five shutter-type field mill sensors (each with sensitivities of better than 1 V/m) located on the top, bottom, port, starboard, and aft positions. As a test of the calibration method, we analyze computer-simulated calibration data (derived from known aircraft and ambient fields) and explicitly determine the errors involved in deriving the variety of calibration matrices. We extend our formalism to arrive at an analytic solution for the ambient field, and again carry all errors explicitly.

  4. Understanding and manipulating the RF fields at high field MRI

    PubMed Central

    Ibrahim, Tamer S.; Hue, YiK-Kiong; Tang, Lin

    2015-01-01

    This paper presents a complete overview of the electromagnetics (radiofrequency aspect) of MRI at low and high fields. Using analytical formulations, numerical modeling (computational electromagnetics), and ultrahigh field imaging experiments, the physics that impacts the electromagnetic quantities associated with MRI, namely (1) the transmit field, (2) receive field, and (3) total electromagnetic power absorption, is analyzed. The physical interpretation of the above-mentioned quantities is investigated by electromagnetic theory, to understand ‘What happens, in terms of electromagnetics, when operating at different static field strengths?’ Using experimental studies and numerical simulations, this paper also examines the physical and technological feasibilities by which all or any of these specified electromagnetic quantities can be manipulated through techniques such as B1 shimming (phased array excitation) and signal combination using a receive array in order to advance MRI at high field strengths. Pertinent to this subject and with highly coupled coils operating at 7 T, this paper also presents the first phantom work on B1 shimming without B1 measurements. PMID:19621335

  5. NMR in rotating magnetic fields: Magic angle field spinning

    SciTech Connect

    Sakellariou, D.; Meriles, C.; Martin, R.; Pines, A.

    2004-09-10

    Magic angle sample spinning has been one of the cornerstones in high-resolution solid state NMR. Spinning frequencies nowadays have increased by at least one order of magnitude over the ones used in the first experiments and the technique has gained tremendous popularity. It is currently a routine procedure in solid-state NMR, high-resolution liquid-state NMR and solid-state MRI. The technique enhances the spectral resolution by averaging away rank 2 anisotropic spin interactions thereby producing isotropic-like spectra with resolved chemical shifts and scalar couplings. Andrew proposed that it should be possible to induce similar effects in a static sample if the direction of the magnetic field is varied, e.g., magic-angle rotation of the B0 field (B0-MAS) and this has been recently demonstrated using electromagnetic field rotation. Here we discuss on the possibilities to perform field rotation using alternative hardware, together with spectroscopic methods to recover isotropic resolution even in cases where the field is not rotating at the magic angle. Extension to higher magnetic fields would be beneficial in situations where the physical manipulation of the sample is inconvenient or impossible. Such situations occur often in materials or biomedical samples where ''ex-situ'' NMR spectroscopy and imaging analysis is needed.

  6. Continuous indicator fields: a novel universal type of molecular fields

    NASA Astrophysics Data System (ADS)

    Sitnikov, Gleb V.; Zhokhova, Nelly I.; Ustynyuk, Yury A.; Varnek, Alexandre; Baskin, Igor I.

    2015-03-01

    A novel type of molecular fields, Continuous Indicator Fields (CIFs), is suggested to provide 3D structural description of molecules. The values of CIFs are calculated as the degree to which a point with given 3D coordinates belongs to an atom of a certain type. They can be used similarly to standard physicochemical fields for building 3D structure-activity models. One can build CIF-based 3D structure-activity models in the framework of the continuous molecular fields approach described earlier (J Comput-Aided Mol Des 27 (5):427-442, 2013) for the case of physicochemical molecular fields. CIFs are thought to complement and further extend traditional physicochemical fields. The models built with CIFs can be interpreted in terms of preferable and undesirable positions of certain types of atoms in space. This helps to understand which changes in chemical structure should be made in order to design a compound possessing desirable properties. We have demonstrated that CIFs can be considered as 3D analogues of 2D topological molecular fragments. The performance of this approach is demonstrated in structure-activity studies of thrombin inhibitors, multidentate N-heterocyclic ligands for Am3+/Eu3+ separation, and coloring dyes.

  7. Algebraic orbifold conformal field theories

    PubMed Central

    Xu, Feng

    2000-01-01

    The unitary rational orbifold conformal field theories in the algebraic quantum field theory and subfactor theory framework are formulated. Under general conditions, it is shown that the orbifold of a given unitary rational conformal field theory generates a unitary modular category. Many new unitary modular categories are obtained. It is also shown that the irreducible representations of orbifolds of rank one lattice vertex operator algebras give rise to unitary modular categories and determine the corresponding modular matrices, which has been conjectured for some time. PMID:11106383

  8. The emerging field of neuroepigenetics.

    PubMed

    Sweatt, J David

    2013-10-30

    Over the past 25 years, the broad field of epigenetics and, over the past decade in particular, the emerging field of neuroepigenetics have begun to have tremendous impact in the areas of learned behavior, neurotoxicology, CNS development, cognition, addiction, and psychopathology. However, epigenetics is such a new field that in most of these areas the impact is more in the category of fascinating implications as opposed to established facts. In this brief commentary, I will attempt to address and delineate some of the open questions and areas of opportunity that discoveries in epigenetics are providing to the discipline of neuroscience.

  9. Electromagnetic field parameters and instrumentation

    NASA Astrophysics Data System (ADS)

    Sheppard, A. R.; Jones, R. A.; Stell, M. E.; Adey, W. R.; Bawin, S.

    1986-07-01

    We studied the effects of the electric and magnetic components of a Loran-C type waveform on three biological systems. Neurochemical assays of brain neurotransmitter substances indicate field-related changes in the levels of norepinephrine in the hippocampus and in the number and affinities of the opiate receptors in the cortex. Behavioral data showed that rats trained in an operant conditioning task did not reliably detect any electric field strength used. Biochemical data demonstrated that the Loran-C field did not modify basal ornithine decarboxylase activity in primary bone cells.

  10. Magnetic Field of Strange Dwarfs

    NASA Astrophysics Data System (ADS)

    Baghdasaryan, D. S.

    2016-03-01

    The generation of a magnetic field in a strange quark star owing to differential rotation of the superfluid and superconducting quark core relative to the normal electron-nuclear crust of the star is examined. The maximum possible magnetic field on the surface is estimated for various models of strange dwarfs. Depending on the configuration parameters, i.e., the mass M and radius R of the star, a range of 103-105 G is found. These values of the magnetic field may be an additional condition for identification of strange dwarfs among the extensive class of observed white dwarfs.

  11. High field gradient particle accelerator

    DOEpatents

    Nation, John A.; Greenwald, Shlomo

    1989-01-01

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

  12. High field gradient particle accelerator

    DOEpatents

    Nation, J.A.; Greenwald, S.

    1989-05-30

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

  13. AC photovoltaic module magnetic fields

    SciTech Connect

    Jennings, C.; Chang, G.J.; Reyes, A.B.; Whitaker, C.M.

    1997-12-31

    Implementation of alternating current (AC) photovoltaic (PV) modules, particularly for distributed applications such as PV rooftops and facades, may be slowed by public concern about electric and magnetic fields (EMF). This paper documents magnetic field measurements on an AC PV module, complementing EMF research on direct-current PV modules conducted by PG and E in 1993. Although not comprehensive, the PV EMF data indicate that 60 Hz magnetic fields (the EMF type of greatest public concern) from PV modules are comparable to, or significantly less than, those from household appliances. Given the present EMF research knowledge, AC PV module EMF may not merit considerable concern.

  14. Approach to Mars Field Geology

    NASA Technical Reports Server (NTRS)

    Muehlberger, William; Rice, James W.; Parker, Timothy; Lipps, Jere H.; Hoffman, Paul; Burchfiel, Clark; Brasier, Martin

    1998-01-01

    The goals of field study on Mars are nothing less than to understand the processes and history of the planet at whatever level of detail is necessary. A manned mission gives us an unprecedented opportunity to use the immense power of the human mind to comprehend Mars in extraordinary detail. To take advantage of this opportunity, it is important to examine how we should approach the field study of Mars. In this effort, we are guided by over 200 years of field exploration experience on Earth as well as six manned missions exploring the Moon.

  15. Measurements of magnetic field alignment

    SciTech Connect

    Kuchnir, M.; Schmidt, E.E.

    1987-11-06

    The procedure for installing Superconducting Super Collider (SSC) dipoles in their respective cryostats involves aligning the average direction of their field with the vertical to an accuracy of 0.5 mrad. The equipment developed for carrying on these measurements is described and the measurements performed on the first few prototypes SSC magnets are presented. The field angle as a function of position in these 16.6 m long magnets is a characteristic of the individual magnet with possible feedback information to its manufacturing procedure. A comparison of this vertical alignment characteristic with a magnetic field intensity (by NMR) characteristic for one of the prototypes is also presented. 5 refs., 7 figs.

  16. Atomic processes in bicircular fields

    NASA Astrophysics Data System (ADS)

    Odžak, S.; Hasović, E.; Becker, W.; Milošević, D. B.

    2016-02-01

    We investigate laser-assisted electron-ion recombination (LAR), high-order harmonic generation (HHG) and above-threshold ionization (ATI) of argon atoms by a bicircular laser field, which consists of two coplanar counter-rotating circularly polarized fields of frequencies rω and sω. The energy of soft x rays generated in the LAR process is analyzed as a function of the incident electron angle and numerical results of direct recombination of electrons with Ar+ ions are presented. We also present the results of HHG by a bicircular field and confirm the selection rules derived earlier for inert-gas atoms in a p ground state. We show that the photoelectron spectra in the ATI process, presented in the momentum plane, as well as the LAR spectra exhibit the same discrete rotational symmetry as the applied field.

  17. Geometric field-line calculations

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Mead, G. D.

    1972-01-01

    Procedure for calculating three components of vector field from spherical harmonic using either geocentric or geodetic coordinates as input and output is described. Three subroutines of computer program are explained. Program is written in FORTRAN for IBM 360 computer.

  18. Reverse engineering quantum field theory

    NASA Astrophysics Data System (ADS)

    Oeckl, Robert

    2012-12-01

    An approach to the foundations of quantum theory is advertised that proceeds by "reverse engineering" quantum field theory. As a concrete instance of this approach, the general boundary formulation of quantum theory is outlined.

  19. Electrochemical formation of field emitters

    DOEpatents

    Bernhardt, A.F.

    1999-03-16

    Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays is disclosed. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area. 12 figs.

  20. Field Lines of Flying Fur.

    ERIC Educational Resources Information Center

    Lapp, David R.

    1996-01-01

    Presents a demonstration that uses insulated conductors and hairs clipped from rabbit fur to help students visualize the electric field in three dimensions and motivate them to try their own variations. (JRH)

  1. The Capacitive Magnetic Field Sensor

    NASA Astrophysics Data System (ADS)

    Zyatkov, D. O.; Yurchenko, A. V.; Balashov, V. B.; Yurchenko, V. I.

    2016-01-01

    The results of a study of sensitive element magnetic field sensor are represented in this paper. The sensor is based on the change of the capacitance with an active dielectric (ferrofluid) due to the magnitude of magnetic field. To prepare the ferrofluid magnetic particles are used, which have a followingdispersion equal to 50 < Ø < 56, 45 < Ø < 50, 40 < Ø < 45 and Ø < 40micron of nanocrystalline alloy of brand 5BDSR. The dependence of the sensitivity of the capacitive element from the ferrofluid with different dispersion of magnetic particles is considered. The threshold of sensitivity and sensitivity of a measuring cell with ferrofluid by a magnetic field was determined. The experimental graphs of capacitance change of the magnitude of magnetic field are presented.

  2. Measuring Earth's Magnetic Field Simply.

    ERIC Educational Resources Information Center

    Stewart, Gay B.

    2000-01-01

    Describes a method for measuring the earth's magnetic field using an empty toilet paper tube, copper wire, clear tape, a battery, a linear variable resistor, a small compass, cardboard, a protractor, and an ammeter. (WRM)

  3. Chapter A6. Field Measurements

    USGS Publications Warehouse

    Wilde, Franceska D.; Radtke, Dean B.

    1998-01-01

    The National Field Manual for the Collection of Water-Quality Data (National Field Manual) provides guidelines and standard procedures for U.S. Geological Survey (USGS) personnel who collect data used to assess the quality of the Nation's surface-water and ground-water resources. Chapter A6 presents procedures and guidelines for the collection of data on air and water temperature, and on dissolved-oxygen concentrations, specific electrical conductance, pH, reduction-oxidation potential, alkalinity, and turbidity in water. Each chapter of the National Field Manual is published separately and revised periodically. Newly published and revised chapters are posted on the World Wide Web on the USGS page 'National Field Manual for the Collection of Water-Quality Data.' The URL for this page is http://pubs.water.usgs.gov/twri9A (accessed August 6, 2005).

  4. Mojave remote sensing field experiment

    NASA Technical Reports Server (NTRS)

    Arvidson, Raymond E.; Petroy, S. B.; Plaut, J. J.; Shepard, Michael K.; Evans, D.; Farr, T.; Greeley, Ronald; Gaddis, L.; Lancaster, N.

    1991-01-01

    The Mojave Remote Sensing Field Experiment (MFE), conducted in June 1988, involved acquisition of Thermal Infrared Multispectral Scanner (TIMS); C, L, and P-band polarimetric radar (AIRSAR) data; and simultaneous field observations at the Pisgah and Cima volcanic fields, and Lavic and Silver Lake Playas, Mojave Desert, California. A LANDSAT Thematic Mapper (TM) scene is also included in the MFE archive. TM-based reflectance and TIMS-based emissivity surface spectra were extracted for selected surfaces. Radiative transfer procedures were used to model the atmosphere and surface simultaneously, with the constraint that the spectra must be consistent with field-based spectral observations. AIRSAR data were calibrated to backscatter cross sections using corner reflectors deployed at target sites. Analyses of MFE data focus on extraction of reflectance, emissivity, and cross section for lava flows of various ages and degradation states. Results have relevance for the evolution of volcanic plains on Venus and Mars.

  5. Real Automation in the Field

    NASA Technical Reports Server (NTRS)

    Munoz, Cesar; Mayero, Micaela; Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    We provide a package of strategies for automation of non-linear arithmetic in PVS. In particular, we describe a simplication procedure for the field of real numbers and a strategy for cancellation of common terms.

  6. Impact of inclusive field trips

    NASA Astrophysics Data System (ADS)

    Gilley, Brett; Atchison, Chris; Feig, Anthony; Stokes, Alison

    2015-08-01

    The geosciences benefit from diverse student perspectives and backgrounds, but the field-based learning requirements pose barriers to students with disabilities. If carefully designed, fieldwork can be made accessible while still meeting expectations of academic rigour.

  7. Electric fields and quantum wormholes

    NASA Astrophysics Data System (ADS)

    Engelhardt, Dalit; Freivogel, Ben; Iqbal, Nabil

    2015-09-01

    Electric fields can thread a classical Einstein-Rosen bridge. Maldacena and Susskind have recently suggested that in a theory of dynamical gravity the entanglement of ordinary perturbative quanta should be viewed as creating a quantum version of an Einstein-Rosen bridge between the particles, or a "quantum wormhole." We demonstrate within low-energy effective field theory that there is a precise sense in which electric fields can also thread such quantum wormholes. We define a nonperturbative "wormhole susceptibility" that measures the ease of passing an electric field through any sort of wormhole. The susceptibility of a quantum wormhole is suppressed by powers of the U (1 ) gauge coupling relative to that for a classical wormhole but can be made numerically equal with a sufficiently large amount of entangled matter.

  8. Gradiometry and gravitomagnetic field detection

    NASA Technical Reports Server (NTRS)

    Mashhoon, Bahram

    1989-01-01

    Gravitomagnetism was apparently first introduced into physics about 120 years ago when major developments in electrodynamics and the strong similarity between Coulomb's law of electricity and Newton's law of gravity led to the hypothesis that mass current generates a fundamental force of gravitational origin analogous to the magnetic force caused by charge current. According to general relativity, the rotation of a body leads to the dragging of the local inertial frames. In the weak-field approximation, the dragging frequency can be interpreted, up to a constant proportionality factor, as a gravitational magnetic field. There is, as yet, no direct evidence regarding the existence of such a field. The possibility is examined of detecting the gravitomagnetic field of the Earth by gravity gradiometry.

  9. The Juno Magnetic Field Investigation

    NASA Astrophysics Data System (ADS)

    Connerney, J. E. P.; Benn, M.; Bjarno, J. B.; Denver, T.; Espley, J.; Jorgensen, J. L.; Jorgensen, P. S.; Lawton, P.; Malinnikova, A.; Merayo, J. M.; Murphy, S.; Odom, J.; Oliversen, R.; Schnurr, R.; Sheppard, D.; Smith, E. J.

    2017-02-01

    The Juno Magnetic Field investigation (MAG) characterizes Jupiter's planetary magnetic field and magnetosphere, providing the first globally distributed and proximate measurements of the magnetic field of Jupiter. The magnetic field instrumentation consists of two independent magnetometer sensor suites, each consisting of a tri-axial Fluxgate Magnetometer (FGM) sensor and a pair of co-located imaging sensors mounted on an ultra-stable optical bench. The imaging system sensors are part of a subsystem that provides accurate attitude information (to ˜20 arcsec on a spinning spacecraft) near the point of measurement of the magnetic field. The two sensor suites are accommodated at 10 and 12 m from the body of the spacecraft on a 4 m long magnetometer boom affixed to the outer end of one of 's three solar array assemblies. The magnetometer sensors are controlled by independent and functionally identical electronics boards within the magnetometer electronics package mounted inside Juno's massive radiation shielded vault. The imaging sensors are controlled by a fully hardware redundant electronics package also mounted within the radiation vault. Each magnetometer sensor measures the vector magnetic field with 100 ppm absolute vector accuracy over a wide dynamic range (to 16 Gauss = 1.6 × 106 nT per axis) with a resolution of ˜0.05 nT in the most sensitive dynamic range (±1600 nT per axis). Both magnetometers sample the magnetic field simultaneously at an intrinsic sample rate of 64 vector samples per second. The magnetic field instrumentation may be reconfigured in flight to meet unanticipated needs and is fully hardware redundant. The attitude determination system compares images with an on-board star catalog to provide attitude solutions (quaternions) at a rate of up to 4 solutions per second, and may be configured to acquire images of selected targets for science and engineering analysis. The system tracks and catalogs objects that pass through the imager field of

  10. Invariants from classical field theory

    SciTech Connect

    Diaz, Rafael; Leal, Lorenzo

    2008-06-15

    We introduce a method that generates invariant functions from perturbative classical field theories depending on external parameters. By applying our methods to several field theories such as Abelian BF, Chern-Simons, and two-dimensional Yang-Mills theory, we obtain, respectively, the linking number for embedded submanifolds in compact varieties, the Gauss' and the second Milnor's invariant for links in S{sup 3}, and invariants under area-preserving diffeomorphisms for configurations of immersed planar curves.

  11. Fields in multilayer beam tubes

    SciTech Connect

    Lambertson, Glen

    1999-08-01

    Equations are presented for calculating the fields from a bunched beam that penetrate into the layers of a beam tube of circular cross section. Starting from the radial wave impedance of an outer surface, the wave functions in inner layers are calculated numerically to obtain field strengths or the longitudinal beam impedance. Examples of a vertex-detector region and of an injection kicker are given.

  12. Evolution of twisted magnetic fields

    SciTech Connect

    Zweibel, E.G.; Boozer, A.H.

    1985-02-01

    The magnetic field of the solar corona evolves quasistatically in response to slowly changing photospheric boundary conditions. The magnetic topology is preserved by the low resistivity of the solar atmosphere. We show that a magnetic flux coordinate system simplifies the problem of calculating field evolution with invariant topology. As an example, we calculate the equilibrium of a thin magnetic flux tube with small twist per unit length.

  13. Small-Scale-Field Dynamo

    SciTech Connect

    Gruzinov, A.; Cowley, S.; Sudan, R. ||

    1996-11-01

    Generation of magnetic field energy, without mean field generation, is studied. Isotropic mirror-symmetric turbulence of a conducting fluid amplifies the energy of small-scale magnetic perturbations if the magnetic Reynolds number is high, and the dimensionality of space {ital d} satisfies 2.103{lt}{ital d}{lt}8.765. The result does not depend on the model of turbulence, incompressibility, and isotropy being the only requirements. {copyright} {ital 1996 The American Physical Society.}

  14. Geomagnetic field detection in rodents

    SciTech Connect

    Olcese, J.; Reuss, S.; Semm, P.

    1988-01-01

    In addition to behavioral evidence for the detection of earth-strength magnetic fields (MF) by rodents, recent investigations have revealed that electrophysiological and biochemical responses to MF occur in the pineal organ and retina of rodents. In addition, ferrimagnetic deposits have been identified in the ethmoidal regions of the rodent skull. These findings point to a new sensory phenomenon, which interfaces with many fields of biology, including neuroscience, psychophysics, behavioral ecology, chronobiology and sensory physiology.

  15. Developing and Fielding Information Dominance

    DTIC Science & Technology

    2002-01-01

    Developing and Fielding Information Dominance Space and Naval Warfare Systems Command’s IT-21 Blocks 1 and 2 2002 Command and Control Research and...00-00-2002 4. TITLE AND SUBTITLE Developing and Fielding Information Dominance 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...force levels were uncertain, the necessary role of information dominance to maintaining strategic superiority was not. Platform Centric Warfare, with its

  16. Field dependence and distraction revisited.

    PubMed

    Blowers, G H

    1976-02-01

    An attempt is made to replicate a former study of the relationship of field dependence as measured by rod-and-frame errors to distraction in an RT paradigm. For two groups of Ss (n = 14) who differed specifically in their dependence upon the tilted frame and were classified as frame-dependent and frame-independent, no relationship of frame (or field) dependence to susceptibility to distraction was found.

  17. Magnetic-Field Hazards Bibliography.

    DTIC Science & Technology

    1985-09-01

    Puchalska, I. B., Influence of magnetic fields on frog sciatic nerve , Biochem. Biophys. Res. Comm. 91:118 (1979). 35. Fardon, 3. C., "Effect of magnetic...fields, Bioelectromagnetic 2:357 (1981). 41. Gaffey, C. T. and Tenforde, T. S., Bioelectric properties of frog sciatic nerves during exposure to...available from: U.S. Dept. of Energy, Bonneville Power Administration, Portland, Oregon 97208 (1982). 29. Levy , R. H., and Jones, G. S., "Plasma

  18. Unitarity of superstring field theory

    NASA Astrophysics Data System (ADS)

    Sen, Ashoke

    2016-12-01

    We complete the proof of unitarity of (compactified) heterotic and type II string field theories by showing that in the cut diagrams only physical states appear in the sum over intermediate states. This analysis takes into account the effect of mass and wave-function renormalization, and the possibility that the true vacuum may be related to the perturbative vacuum by small shifts in the string fields.

  19. Electric Field Containerless Processing Technology

    NASA Technical Reports Server (NTRS)

    Elleman, D. D.; Rhim, W. K.

    1985-01-01

    The objective of this task is to develop the science and technology base required to design and construct a high temperature electric field positioning module that could be used by materials scientists to conduct containerless science experiments in a low gravity environment. Containerless science modules that employ electric fields to position and manipulate samples offer several advantages over acoustic or electromagnetic systems. The electric field system will operate not only at atmospheric pressures but also in a vacuum, in contrast to the acoustic modules which can only operate in atmosphere where the acoustic forces are sufficient. The electric field technique puts minimum energy into the sample, whereas the electromagnetic system can deposit energy into the sample through eddy current heat as well as physical mixing in the sample. Two types of electric field modules have been constructed and tested to date. One employs a charged sample and uses electrostatic forces to position and control the sample. The second type of module induces electrical polarization of the sample and electric field gradients to position and control the sample.

  20. Stochastic-field cavitation model

    SciTech Connect

    Dumond, J.; Magagnato, F.; Class, A.

    2013-07-15

    Nonlinear phenomena can often be well described using probability density functions (pdf) and pdf transport models. Traditionally, the simulation of pdf transport requires Monte-Carlo codes based on Lagrangian “particles” or prescribed pdf assumptions including binning techniques. Recently, in the field of combustion, a novel formulation called the stochastic-field method solving pdf transport based on Eulerian fields has been proposed which eliminates the necessity to mix Eulerian and Lagrangian techniques or prescribed pdf assumptions. In the present work, for the first time the stochastic-field method is applied to multi-phase flow and, in particular, to cavitating flow. To validate the proposed stochastic-field cavitation model, two applications are considered. First, sheet cavitation is simulated in a Venturi-type nozzle. The second application is an innovative fluidic diode which exhibits coolant flashing. Agreement with experimental results is obtained for both applications with a fixed set of model constants. The stochastic-field cavitation model captures the wide range of pdf shapes present at different locations.

  1. Magnetic fields during galaxy mergers

    NASA Astrophysics Data System (ADS)

    Rodenbeck, Kai; Schleicher, Dominik R. G.

    2016-09-01

    Galaxy mergers are expected to play a central role for the evolution of galaxies and may have a strong effect on their magnetic fields. We present the first grid-based 3D magnetohydrodynamical simulations investigating the evolution of magnetic fields during merger events. For this purpose, we employed a simplified model considering the merger event of magnetized gaseous disks in the absence of stellar feedback and without a stellar or dark matter component. We show that our model naturally leads to the production of two peaks in the evolution of the average magnetic field strength within 5 kpc, within 25 kpc, and on scales in between 5 and 25 kpc. The latter is consistent with the peak in the magnetic field strength previously reported in a merger sequence of observed galaxies. We show that the peak on the galactic scale and in the outer regions is most likely due to geometrical effects, as the core of one galaxy enters the outskirts of the other one. In addition, the magnetic field within the central ~5 kpc is physically enhanced, which reflects the enhancement in density that is due to efficient angular momentum transport. We conclude that high-resolution observations of the central regions will be particularly relevant for probing the evolution of magnetic field structures during merger events.

  2. Static magnetic fields: animal studies.

    PubMed

    Saunders, Richard

    2005-01-01

    Various experimental studies carried out over the last 30-40 years have examined the effects of the chronic or acute exposure of laboratory animals to static magnetic fields. Many of the earlier studies have been adequately reviewed elsewhere; few adverse effects were identified. This review focuses on studies carried out more recently, mostly those using vertebrates, particularly mammals. Four main areas of investigation have been covered, viz., nervous system and behavioural studies, cardiovascular system responses, reproduction and development, and genotoxicity and cancer. Work on the role of the natural geomagnetic field in animal orientation and migration has been omitted. Generally, the acute responses found during exposure to static fields above about 4 T are consistent with those found in volunteer studies, namely the induction of flow potentials around the heart and the development of aversive/avoidance behaviour resulting from body movement in such fields. No consistently demonstrable effects of exposure to fields of approximately 1T and above have been seen on other behavioural or cardiovascular endpoints. In addition, no adverse effects of such fields on reproduction and development or on the growth and development of tumours have been firmly established. Overall, however, far too few animal studies have been carried out to reach any firm conclusions.

  3. Saturn's Magnetic Field and Magnetosphere.

    PubMed

    Smith, E J; Davis, L; Jones, D E; Coleman, P J; Colburn, D S; Dyal, P; Sonett, C P

    1980-01-25

    The Pioneer Saturn vector helium magnetometer has detected a bow shock and magnetopause at Saturn and has provided an accurate characterization of the planetary field. The equatorial surface field is 0.20 gauss, a factor of 3 to 5 times smaller than anticipated on the basis of attempted scalings from Earth and Jupiter. The tilt angle between the magnetic dipole axis and Saturn's rotation axis is < 1 degrees , a surprisingly small value. Spherical harmonic analysis of the measurements shows that the ratio of quadrupole to dipole moments is < 10 percent, indicating that the field is more uniform than those of the Earth or Jupiter and consistent with Saturn having a relatively small core. The field in the outer magnetosphere shows systematic departures from the dipole field, principally a compression of the field near noon and an equatorial orientation associated with a current sheet near dawn. A hydromagnetic wake resulting from the interaction of Titan with the rotating magnetosphere appears to have been observed.

  4. Optical sensor of magnetic fields

    DOEpatents

    Butler, M.A.; Martin, S.J.

    1986-03-25

    An optical magnetic field strength sensor for measuring the field strength of a magnetic field comprising a dilute magnetic semi-conductor probe having first and second ends, longitudinally positioned in the magnetic field for providing Faraday polarization rotation of light passing therethrough relative to the strength of the magnetic field. Light provided by a remote light source is propagated through an optical fiber coupler and a single optical fiber strand between the probe and the light source for providing a light path therebetween. A polarizer and an apparatus for rotating the polarization of the light is provided in the light path and a reflector is carried by the second end of the probe for reflecting the light back through the probe and thence through the polarizer to the optical coupler. A photo detector apparatus is operably connected to the optical coupler for detecting and measuring the intensity of the reflected light and comparing same to the light source intensity whereby the magnetic field strength may be calculated.

  5. Transient scattering from dielectric cylinders - E-field, H-field, and combined field solutions

    NASA Technical Reports Server (NTRS)

    Vechinski, Douglas A.; Rao, Sadasiva M.

    1992-01-01

    In this work, the problem of transient scattering by arbitrarily shaped two-dimensional dielectric cylinders is solved using the marching-on-in-time technique. The dielectric problem is approached via the equivalence principle. Three different formulations, namely, the electric field integral equation formulation, the magnetic field integral equation formulation, and the combined field integral equation formulation are considered. Numerical results are presented for two cross sections, namely, a circle and a square, and compared with inverse discrete Fourier transform (IDFT) techniques. In each case, good agreement is obtained with the IDFT solution.

  6. Electrophoresis in strong electric fields.

    PubMed

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  7. Hydrogen Field Test Standard: Laboratory and Field Performance

    PubMed Central

    Pope, Jodie G.; Wright, John D.

    2015-01-01

    The National Institute of Standards and Technology (NIST) developed a prototype field test standard (FTS) that incorporates three test methods that could be used by state weights and measures inspectors to periodically verify the accuracy of retail hydrogen dispensers, much as gasoline dispensers are tested today. The three field test methods are: 1) gravimetric, 2) Pressure, Volume, Temperature (PVT), and 3) master meter. The FTS was tested in NIST's Transient Flow Facility with helium gas and in the field at a hydrogen dispenser location. All three methods agree within 0.57 % and 1.53 % for all test drafts of helium gas in the laboratory setting and of hydrogen gas in the field, respectively. The time required to perform six test drafts is similar for all three methods, ranging from 6 h for the gravimetric and master meter methods to 8 h for the PVT method. The laboratory tests show that 1) it is critical to wait for thermal equilibrium to achieve density measurements in the FTS that meet the desired uncertainty requirements for the PVT and master meter methods; in general, we found a wait time of 20 minutes introduces errors < 0.1 % and < 0.04 % in the PVT and master meter methods, respectively and 2) buoyancy corrections are important for the lowest uncertainty gravimetric measurements. The field tests show that sensor drift can become a largest component of uncertainty that is not present in the laboratory setting. The scale was calibrated after it was set up at the field location. Checks of the calibration throughout testing showed drift of 0.031 %. Calibration of the master meter and the pressure sensors prior to travel to the field location and upon return showed significant drifts in their calibrations; 0.14 % and up to 1.7 %, respectively. This highlights the need for better sensor selection and/or more robust sensor testing prior to putting into field service. All three test methods are capable of being successfully performed in the field and give

  8. Structure formation with scalar field dark matter: the field approach

    SciTech Connect

    Magaña, Juan; Sánchez-Salcedo, F.J.; Matos, Tonatiuh; Suárez, Abril E-mail: tmatos@fis.cinvestav.mx E-mail: jsanchez@astro.unam.mx

    2012-10-01

    We study the formation of structure in the Universe assuming that dark matter can be described by a scalar field Φ-tilde with a potential V(Φ) = −m{sup 2}Φ-tilde {sup 2}/2+λΦ-tilde {sup 4}/4. We derive the evolution equations of the scalar field in the linear regime of perturbations. We investigate the symmetry breaking and possibly a phase transition of this scalar field in the early Universe. At low temperatures, the scalar perturbations have an oscillating growing mode and therefore, this kind of dark matter could lead to the formation of gravitational structures. In order to study the nonlinear regime, we use the spherical collapse model and show that, in the quadratic potential limit, this kind of dark matter can form virialized structures. The main difference with the traditional Cold Dark Matter paradigm is that the formation of structure in the scalar field model can occur at earlier times. Thus, if the dark matter behaves as a scalar field, large galaxies are expected to be formed already at high redshifts.

  9. THOR Electric Field Instrument - EFI

    NASA Astrophysics Data System (ADS)

    Khotyaintsev, Yuri; Bale, Stuart D.; Bonnell, John W.; Lindqvist, Per-Arne; Phal, Yamuna; Rothkaehl, Hanna; Soucek, Jan; Vaivads, Andris; Åhlen, Lennart

    2016-04-01

    Turbulence Heating ObserveR (THOR) is the first mission ever flown in space dedicated to plasma turbulence. The Electric Field Instrument (EFI) will measure the vector electric field from 0 to 200 kHz. EFI consists of two sets of sensors: Spin-plane Double Probes (EFI-SDP) providing high sensitivity DC electric field in the spacecraft spin plane (2D), and the High-Frequency Antenna (EFI-HFA) providing 3D electric field at frequencies above ~1 kHz. EFI-SDP consists of 4 biased spherical probes extended on 50 m long wire booms, 90 degrees apart in the spin plane, giving a 100 m baseline for each of the two spin-plane electric field components. EFI-HFA consists of 6 x 1.25 m long monopoles, forming 3 dipolar antennas crossed at 90 degrees to each other. In addition to the sensors, EFI contains HFA and SDP pre-amplifiers, as well as bias electronics boards (BEBs) hosted in the man electronics box of the Field and Wave processor (FWP). As THOR spacecraft has a sun-pointing spin axis, EFI-SDP measures the electric field in the plane approximately orthogonal to the sun using long wire booms. The sun-pointing attitude greatly reduces errors due to wake effects and asymmetric photoelectron clouds, enabling the highly accurate in comparison to earlier missions ±0.1 mV/m near-DC electric field measurements. Interferometry using the electric field probes can be used to infer wavelengths and scale sizes at the smallest scales in the plasma. EFI also measures the floating potential of the satellite, which can be used to estimate the plasma density at very high time resolution (up to a few hundred Hz). The sun-pointing attitude greatly reduces changes in the illuminated area, and hence the associated spin-dependent errors. In combination with densities derived from the observed plasma frequency emission line, EFI monitors the plasma density from DC to a few hundred Hz. EFI measurements characterize electric field and density variations associated with kinetic scale plasma

  10. Magnetic fields in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Krause, Marita

    2015-03-01

    The magnetic field structure in edge-on galaxies observed so far shows a plane-parallel magnetic field component in the disk of the galaxy and an X-shaped field in its halo. The plane-parallel field is thought to be the projected axisymmetric (ASS) disk field as observed in face-on galaxies. Some galaxies addionionally exhibit strong vertical magnetic fields in the halo right above and below the central region of the disk. The mean-field dynamo theory in the disk cannot explain these observed fields without the action of a wind, which also probably plays an important role to keep the vertical scale heights constant in galaxies of different Hubble types and star formation activities, as has been observed in the radio continuum: At λ6 cm the vertical scale heights of the thin disk and the thick disk/halo in a sample of five edge-on galaxies are similar with a mean value of 300 +/- 50 pc for the thin disk and 1.8 +/- 0.2 kpc for the thick disk (a table and references are given in Krause 2011) with our sample including the brightest halo observed so far, NGC 253, with strong star formation, as well as one of the weakest halos, NGC 4565, with weak star formation. If synchrotron emission is the dominant loss process of the relativistic electrons the outer shape of the radio emission should be dumbbell-like as has been observed in several edge-on galaxies like e.g. NGC 253 (Heesen et al. 2009) and NGC 4565. As the synchrotron lifetime t syn at a single frequency is proportional to the total magnetic field strength B t -1.5, a cosmic ray bulk speed (velocity of a galactic wind) can be defined as v CR = h CR /t syn = 2 h z /t syn , where h CR and h z are the scale heights of the cosmic rays and the observed radio emission at this freqnency. Similar observed radio scale heights imply a self regulation mechanism between the galactic wind velocity, the total magnetic field strength and the star formation rate SFR in the disk: v CR ~ B t 1.5 ~ SFR ~ 0.5 (Niklas & Beck 1997).

  11. Observations of Interstellar Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Crutcher, R.; Heiles, C.; Troland, T.

    This article describes how interstellar magnetic fields are detected, measured, and mapped, the results of such observations, and the role played by interstellar magnetic fields in the physics of the interstellar medium. A goal of the observations is the measurement of the morphology and strengths of the uniform (Bu) and random (Br) components of magnetic fields. Observational techniques probe either the component of B parallel to the line of sight (B_parallel) or in the plane of the sky (B_⊥). Tracers of B_parallel are Faraday rotation of the position angle of linearly polarized radiation and Zeeman splitting of spectral lines. Tracers of B_⊥ are the strength of synchrotron radiation and linear polarization of syn chrotron radiation and of emission or absorption from dust and spectral lines. Starlight polarization shows that on large spatial scales the Galactic magnetic field is not heavily tangled (B_u/B_r ≈ 0.7 - 1.0), that the field is generally parallel to the Galactic plane near the plane, that the local field points approximately along the local spiral arm (pitch angle 9.4(°) , center of curvature 7.8 kpc distant towards ℓ ≈ -15.4(°) ), and that off the Galactic plane there is considerable small-scale structure to the field. Galactic synchrotron emission shows magnetic spiral arms with a total strength B_t ≈ 6 #55G and B_u ≈ 4 #55G. Pulsar data show evidence for reversals of the field direction with Galactic radius and yield B_r ≈ 5 #55G and B_u ≈ 1.5 #55G; the morphology of the large-scale mean field is consistent with dynamo generation. H I Zeeman detections for diffuse clouds yield B_parallel char 126 5 - 20 #55G with many limits B_parallel #55G. A recent survey of Galactic H I in absorption against extragalactic sources confirms the result that the fields in diffuse clouds are often quite weak. The critical parameter for evaluating the importance of magnetic fields in star formation is the ratio of the mass to the magnetic flux, M

  12. Searching for converging research using field to field citations

    PubMed Central

    Noyons, Ed. C. M.; Van Raan, Anthony F. J.

    2010-01-01

    We define converging research as the emergence of an interdisciplinary research area from fields that did not show interdisciplinary connections before. This paper presents a process to search for converging research using journal subject categories as a proxy for fields and citations to measure interdisciplinary connections, as well as an application of this search. The search consists of two phases: a quantitative phase in which pairs of citing and cited fields are located that show a significant change in number of citations, followed by a qualitative phase in which thematic focus is sought in publications associated with located pairs. Applying this search on publications from the Web of Science published between 1995 and 2005, 38 candidate converging pairs were located, 27 of which showed thematic focus, and 20 also showed a similar focus in the other, reciprocal pair. PMID:21297857

  13. Scalar field dark matter and the Higgs field

    NASA Astrophysics Data System (ADS)

    Bertolami, O.; Cosme, Catarina; Rosa, João G.

    2016-08-01

    We discuss the possibility that dark matter corresponds to an oscillating scalar field coupled to the Higgs boson. We argue that the initial field amplitude should generically be of the order of the Hubble parameter during inflation, as a result of its quasi-de Sitter fluctuations. This implies that such a field may account for the present dark matter abundance for masses in the range 10-6-10-4eV, if the tensor-to-scalar ratio is within the range of planned CMB experiments. We show that such mass values can naturally be obtained through either Planck-suppressed non-renormalizable interactions with the Higgs boson or, alternatively, through renormalizable interactions within the Randall-Sundrum scenario, where the dark matter scalar resides in the bulk of the warped extra-dimension and the Higgs is confined to the infrared brane.

  14. Magnetoconvection in sheared magnetic fields

    SciTech Connect

    Bian, N. H.; Garcia, O. E.

    2008-10-15

    The development of magnetoconvection in a sheared magnetic field is investigated. The equilibrium magnetic field B{sub 0} is horizontal and its orientation varies linearly along the vertical axis. Preliminary consideration of the transition from the inertial to the viscous regime of the gravitational resistive interchange instability, reveals that the latter is characterized by the existence of viscoresistive boundary layers of vertical width which scales as Q{sup -1/6}, where Q is the Chandrasekhar number. The situation is analogous to the one encountered in magnetically confined laboratory plasmas, where convective flows are constrained by the magnetic shear to develop in boundary layers located around resonant magnetic surfaces in order to fulfill the 'interchange condition'k{center_dot}B{sub 0}=0, where k is the wave vector of the magnetic perturbation. It follows that when the effect of thermal diffusion is taken into account in the process, convection can only occur above a certain critical value of the Rayleigh number which scales as Q{sup 2/3} for large Q. At the onset, the convection pattern is a superposition of identically thin convective rolls everywhere aligned with the local magnetic field lines and which therefore adopt the magnetic field geometry, a situation also reminiscent of the penumbra of sunspots. Using this degeneracy, equations describing the weakly nonlinear state are obtained and discussed. A reduced magnetohydrodynamic description of magnetoconvection is introduced. Since it is valid for arbitrary magnetic field configurations, it allows a simple extension to the case where there exists an inclination between the direction of gravity and the plane spanned by the equilibrium magnetic field. These reduced magnetohydrodynamic equations are proposed as a powerful tool for further investigations of magnetoconvection in more complex field line geometries.

  15. Anomalous toroidal field penetration in Tormac V

    SciTech Connect

    Feinberg, B.; Vaucher, B. G.; Shaw, R. S.; Vella, M. C.

    1981-07-01

    We investigate magnetic field penetration into a cool, collisional, magnetized plasma in Tormac V. Magnetic probe and laser interferometer studies reveal anomalous penetration of the applied toroidal field into a plasma with an initial parallel bias toroidal field. The applied poloidal field, however, formed a well-defined magnetic front which was effective at sweeping up particles. Lastly, strong shear in the vacuum magnetic field does not inhibit the apparent decoupling of the applied toroidal field from the applied poloidal field.

  16. Primordial magnetic fields from self-ordering scalar fields

    SciTech Connect

    Horiguchi, Kouichirou; Ichiki, Kiyotomo; Sugiyama, Naoshi; Sekiguchi, Toyokazu E-mail: ichiki@a.phys.nagoya-u.ac.jp E-mail: naoshi@nagoya-u.jp

    2015-04-01

    A symmetry-breaking phase transition in the early universe could have led to the formation of cosmic defects. Because these defects dynamically excite not only scalar and tensor type cosmological perturbations but also vector type ones, they may serve as a source of primordial magnetic fields. In this study, we calculate the time evolution and the spectrum of magnetic fields that are generated by a type of cosmic defects, called global textures, using the non-linear sigma (NLSM) model. Based on the standard cosmological perturbation theory, we show, both analytically and numerically, that a vector-mode relative velocity between photon and baryon fluids is induced by textures, which inevitably leads to the generation of magnetic fields over a wide range of scales. We find that the amplitude of the magnetic fields is given by B∼10{sup −9}((1+z)/10{sup 3}){sup −2.5}(v/m{sub pl}){sup 2}(k/Mpc{sup −1}){sup 3.5}/√N Gauss in the radiation dominated era for k∼< 1 Mpc{sup −1}, with v being the vacuum expectation value of the O(N) symmetric scalar fields. By extrapolating our numerical result toward smaller scales, we expect that B∼ 10{sup −14.5}((1+z)/10{sup 3}){sup 1/2}(v/m{sub pl}){sup 2}(k/Mpc{sup −1}){sup 1/2}/√N Gauss on scales of k∼> 1 Mpc{sup −1} at redshift 0z∼> 110. This might be a seed of the magnetic fields observed on large scales today.

  17. Interaction of the geomagnetic field with northward interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    Bhattarai, Shree Krishna

    The interaction of the solar wind with Earth's magnetic field causes the transfer of momentum and energy from the solar wind to geospace. The study of this interaction is gaining significance as our society is becoming more and more space based, due to which, predicting space weather has become more important. The solar wind interacts with the geomagnetic field primarily via two processes: viscous interaction and the magnetic reconnection. Both of these interactions result in the generation of an electric field in Earth's ionosphere. The overall topology and dynamics of the magnetosphere, as well as the electric field imposed on the ionosphere, vary with speed, density, and magnetic field orientation of the solar wind as well as the conductivity of the ionosphere. In this dissertation, I will examine the role of northward interplanetary magnetic field (IMF) and discuss the global topology of the magnetosphere and the interaction with the ionosphere using results obtained from the Lyon-Fedder-Mobarry (LFM) simulation. The electric potentials imposed on the ionosphere due to viscous interaction and magnetic reconnection are called the viscous and the reconnection potentials, respectively. A proxy to measure the overall effect of these potentials is to measure the cross polar potential (CPP). The CPP is defined as the difference between the maximum and the minimum of the potential in a given polar ionosphere. I will show results from the LFM simulation showing saturation of the CPP during periods with purely northward IMF of sufficiently large magnitude. I will further show that the viscous potential, which was assumed to be independent of IMF orientation until this work, is reduced during periods of northward IMF. Furthermore, I will also discuss the implications of these results for a simulation of an entire solar rotation.

  18. Thomson scattering in a magnetic field. II - Arbitrary field orientation

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara A.

    1991-01-01

    This paper presents solutions to the equation of transfer for Thomson scattering in a constant magnetic field of arbitrary orientation. Results from several atmospheres are combined to give the flux from a dipole star. The results are compared to the polarization data of the magnetic white dwarf Grw + 70 deg 8247. The fit is good, though it implies a very large polarization in the ultraviolet. Thomson scattering is not thought to be an important opacity source in white dwarfs, so the good fit is either fortuitous or is perhaps explained by assuming the magnetic field affects the polarization processes in all opacities similarly.

  19. Field Markup Language: biological field representation in XML.

    PubMed

    Chang, David; Lovell, Nigel H; Dokos, Socrates

    2007-01-01

    With an ever increasing number of biological models available on the internet, a standardized modeling framework is required to allow information to be accessed or visualized. Based on the Physiome Modeling Framework, the Field Markup Language (FML) is being developed to describe and exchange field information for biological models. In this paper, we describe the basic features of FML, its supporting application framework and its ability to incorporate CellML models to construct tissue-scale biological models. As a typical application example, we present a spatially-heterogeneous cardiac pacemaker model which utilizes both FML and CellML to describe and solve the underlying equations of electrical activation and propagation.

  20. Explaining Mercury's peculiar magnetic field

    NASA Astrophysics Data System (ADS)

    Wicht, Johannes; Cao, Hao; Heyner, Daniel; Dietrich, Wieland; Christensen, Ulrich R.

    2014-05-01

    MESSENGER magnetometer data revealed that Mercury's magnetic field is not only particularly weak but also has a peculiar geometry. The MESSENGER team finds that the location of the magnetic equator always lies significantly north of the geographic equator, is largely independent of the distance to the planet, and also varies only weakly with longitude. The field is best described by an axial dipole that is offset to the north by about 20% of the planetary radius. In terms of classical Gauss coefficients, this translates into a low axial dipole component of g10= -190 nT but a relatively large axial quadrupole contribution that amounts to roughly 40% of this value. The axial octupole is also sizable while higher harmonic contributions are much weaker. Very remarkable is also the fact that the equatorial dipole contribution is very small, consistent with a dipole tilt below 0.8 degree, and this is also true for the other non-axisymmetic field contributions. We analyze several numerical dynamos concerning their capability of explaining Mercury's magnetic field. Classical schemes geared to model the geomagnetic field typically show a much weaker quadrupole component and thus a smaller offset. The onset only becomes larger when the dynamo operates in the multipolar regime at higher Rayleigh numbers. However, since the more complex dynamics generally promotes all higher multipole contributions the location of the magnetic equator varies strongly with longitude and distance to the planet. The situation improves when introducing a stably stratified outer layer in the dynamo region, representing either a rigid FeS layer or a sub-adiabatic core-mantle boundary heat flux. This layer filters out the higher harmonic contributions and the field not only becomes sufficiently weak but also assumes a Mercury like offset geometry during a few percent of the simulation time. To increase the likelihood for the offset configuration, the north-south symmetry must be permanently broken

  1. Cryopumping Field Joint Can Testing

    NASA Technical Reports Server (NTRS)

    Johnson, Wesley L.; Fesmire, James E.; Meneghelli, Barry E.

    2011-01-01

    For long installations, vacuum jacketed piping often comes in 40 foot sections that are butt welded together in the field. A short can is then welded over the bare pipe connection to allow for insulation to be protected from the environment. Traditionally, the field joint is insulated with multilayer insulation and a vacuum is pulled on the can to minimize heat leak through the bare section and prevent frost from forming on the pipe section. The vacuum jacketed lines for the Ares I mobile launch platform were to be a combined 2000 feet long, with 60+ pipe sections and field joint cans. Historically, Kennedy Space Center has drilled a hole in the long sections to create a common vacuum with the field joint can to minimize maintenance on the vacuum jacketed piping. However, this effort looked at ways to use a passive system that didn't require a vacuum, but may cryopump to create its own vacuum. Various forms of aerogel, multilayer insulations, and combinations thereof were tested to determine the best method of insulating the field joint while minimizing maintenance and thermal losses.

  2. Electromagnetic fields in cased borehole

    SciTech Connect

    Lee, Ki Ha; Kim, Hee Joon; Uchida, Toshihiro

    2001-07-20

    Borehole electromagnetic (EM) measurements, using fiberglass-cased boreholes, have proven useful in oil field reservoir characterization and process monitoring (Wilt et al., 1995). It has been presumed that these measurements would be impossible in steel-cased wells due to the very large EM attenuation and phase shifts. Recent laboratory and field studies have indicated that detection of EM signals through steel casing should be possible at low frequencies, and that these data provide a reasonable conductivity image at a useful scale. Thus, we see an increased application of this technique to mature oilfields, and an immediate extension to geothermal industry as well. Along with the field experiments numerical model studies have been carried out for analyzing the effect of steel casing to the EM fields. The model used to be an infinitely long uniform casing embedded in a homogeneous whole space. Nevertheless, the results indicated that the formation signal could be accurately recovered if the casing characteristics were independently known (Becker et al., 1998; Lee el al., 1998). Real steel-cased wells are much more complex than the simple laboratory models used in work to date. The purpose of this study is to develop efficient numerical methods for analyzing EM fields in realistic settings, and to evaluate the potential application of EM technologies to cross-borehole and single-hole environment for reservoir characterization and monitoring.

  3. Variational methods for field theories

    NASA Astrophysics Data System (ADS)

    Ben-Menahem, Shahar

    1986-09-01

    The thesis is presented in four parts dealing with field theory models: Periodic Quantum Electrodynamics (PQED) in (2+1) dimensions, free scalar field theory in (1+1) dimensions, the Quantum XY model in (1+1) dimensions, and the (1+1) dimensional Ising model in a transverse magnetic field. The last three parts deal exclusively with variational methods; the PQED part involves mainly the path integral approach. The PQED calculation results in a better understanding of the connection between electric confinement through monopole screening, and confinement through tunneling between degenerate vacua. Free field theory is used as a laboratory for a new variational blocking truncation approximation, in which the high frequency modes in a block are truncated to wave functions that depend on the slower background model (Born Oppenheimer approximation). For the XY model, several trial wave functions for the ground state are explored, with an emphasis on the periodic Gaussian. In the 4th part, the transfer matrix method is used to find a good (non blocking) trial ground state for the Ising model in a transverse magnetic field in (1+1) dimensions.

  4. Gene transcription and electromagnetic fields

    SciTech Connect

    Henderson, A.S.

    1992-01-01

    Our overall aim is to obtain sufficient information to allow us to ultimately determine whether ELF EM field exposure is an initiating factor in neoplastic transformation and/or if exposure can mimic characteristics of the second-step counterpart in neoplastic disease. This aim is based on our previous findings that levels of some transcripts are increased in cells exposed to EM fields. While the research is basic in nature, the ramifications have bearing on the general safety of exposure to EM fields in industrial and everyday life. A large array of diverse biological effects are reported to occur as the result of exposure to elf EM fields, suggesting that the cell response to EM fields is at a basic level, presumably initiated by molecular and/or biophysical events at the cell membrane. The hypothesized route is a signal transduction pathway involving membrane calcium fluxes. Information flow resulting from signal transduction can mediate the induction of regulatory factors in the cell, and directly affect how transcription is regulated.

  5. Inversion of spinning sound fields.

    PubMed

    Carley, Michael

    2009-02-01

    A method is presented for the reconstruction of rotating monopole source distributions using acoustic pressures measured on a sideline parallel to the source axis. The method requires no a priori assumptions about the source other than that its strength at the frequency of interest varies sinusoidally in azimuth on the source disk so that the radiated acoustic field is composed of a single circumferential mode. When multiple azimuthal modes are present, the acoustic field can be decomposed into azimuthal modes and the method applied to each mode in sequence. The method proceeds in two stages, first finding an intermediate line source derived from the source distribution and then inverting this line source to find the radial variation in source strength. A far-field form of the radiation integrals is derived, showing that the far-field pressure is a band-limited Fourier transform of the line source, establishing a limit on the quality of source reconstruction, which can be achieved using far-field measurements. The method is applied to simulated data representing wind-tunnel testing of a ducted rotor system (tip Mach number of 0.74) and to control of noise from an automotive cooling fan (tip Mach number of 0.14), studies which have appeared in the literature of source identification.

  6. Small fields: Nonequilibrium radiation dosimetry

    SciTech Connect

    Das, Indra J.; Ding, George X.; Ahnesjoe, Anders

    2008-01-15

    Advances in radiation treatment with beamlet-based intensity modulation, image-guided radiation therapy, and stereotactic radiosurgery (including specialized equipments like CyberKnife, Gamma Knife, tomotherapy, and high-resolution multileaf collimating systems) have resulted in the use of reduced treatment fields to a subcentimeter scale. Compared to the traditional radiotherapy with fields {>=}4x4 cm{sup 2}, this can result in significant uncertainty in the accuracy of clinical dosimetry. The dosimetry of small fields is challenging due to nonequilibrium conditions created as a consequence of the secondary electron track lengths and the source size projected through the collimating system that are comparable to the treatment field size. It is further complicated by the prolonged electron tracks in the presence of low-density inhomogeneities. Also, radiation detectors introduced into such fields usually perturb the level of disequilibrium. Hence, the dosimetric accuracy previously achieved for standard radiotherapy applications is at risk for both absolute and relative dose determination. This article summarizes the present knowledge and gives an insight into the future procedures to handle the nonequilibrium radiation dosimetry problems. It is anticipated that new miniature detectors with controlled perturbations and corrections will be available to meet the demand for accurate measurements. It is also expected that the Monte Carlo techniques will increasingly be used in assessing the accuracy, verification, and calculation of dose, and will aid perturbation calculations of detectors used in small and highly conformal radiation beams.

  7. Quantum mechanics of Proca fields

    NASA Astrophysics Data System (ADS)

    Zamani, Farhad; Mostafazadeh, Ali

    2009-05-01

    We construct the most general physically admissible positive-definite inner product on the space of Proca fields. Up to a trivial scaling this defines a five-parameter family of Lorentz invariant inner products that we use to construct a genuine Hilbert space for the quantum mechanics of Proca fields. If we identify the generator of time translations with the Hamiltonian, we obtain a unitary quantum system that describes first-quantized Proca fields and does not involve the conventional restriction to the positive-frequency fields. We provide a rather comprehensive analysis of this system. In particular, we examine the conserved current density responsible for the conservation of the probabilities, explore the global gauge symmetry underlying the conservation of the probabilities, obtain a probability current density, construct position, momentum, helicity, spin, and angular momentum operators, and determine the localized Proca fields. We also compute the generalized parity (P), generalized time-reversal (T), and generalized charge or chirality (C) operators for this system and offer a physical interpretation for its PT-, C-, and CPT-symmetries.

  8. Nonlocal and quasilocal field theories

    NASA Astrophysics Data System (ADS)

    Tomboulis, E. T.

    2015-12-01

    We investigate nonlocal field theories, a subject that has attracted some renewed interest in connection with nonlocal gravity models. We study, in particular, scalar theories of interacting delocalized fields, the delocalization being specified by nonlocal integral kernels. We distinguish between strictly nonlocal and quasilocal (compact support) kernels and impose conditions on them to insure UV finiteness and unitarity of amplitudes. We study the classical initial value problem for the partial integro-differential equations of motion in detail. We give rigorous proofs of the existence but accompanying loss of uniqueness of solutions due to the presence of future, as well as past, "delays," a manifestation of acausality. In the quantum theory we derive a generalization of the Bogoliubov causality condition equation for amplitudes, which explicitly exhibits the corrections due to nonlocality. One finds that, remarkably, for quasilocal kernels all acausal effects are confined within the compact support regions. We briefly discuss the extension to other types of fields and prospects of such theories.

  9. NCSX Toroidal Field Coil Design

    SciTech Connect

    Kalish, M.; Rushinski, J.; Myatt, L.; Brooks, A.; Dahlgren, F.; Chrzanowski, J.; Reiersen, W.; Freudenberg, K.

    2005-10-07

    The National Compact Stellarator Experiment (NCSX) is an experimental device whose design and construction is underway at the Department of Energy's Princeton Plasma Physics Laboratory (PPPL). The primary coil systems for the NCSX device consist of the twisted plasma-shaping Modular Coils, the Poloidal Field Coils, and the Toroidal Field (TF) Coils. The TF Coils are D-shaped coils wound from hollow copper conductor, and vacuum impregnated with a glass-epoxy resin system. There are 18 identical, equally spaced TF coils providing 1/R field at the plasma. They operate within a cryostat, and are cooled by LN2, nominally, to 80K. Wedge shaped castings are assembled to the inboard face of these coils, so that inward radial loads are reacted via the nesting of each of the coils against their adjacent partners. This paper outlines the TF Coil design methodology, reviews the analysis results, and summarizes how the design and analysis support the design requirements.

  10. Persistently anomalous Pacific geomagnetic fields

    NASA Astrophysics Data System (ADS)

    Johnson, Catherine L.; Constable, Catherine G.

    A new average geomagnetic field model for the past 3kyr (ALS3K) helps bridge a large temporal sampling gap between historical models and more traditional paleomagnetic studies spanning the last 5 Myr. A quasi-static feature seen historically in the central Pacific has the opposite sign in ALS3K; its structure is similar to, but of larger amplitude than, that in the time-averaged geomagnetic field for the last 5 Myr. Anomalous geomagnetic fields exist beneath the Pacific over timescales ranging from 10²-106 years. It is unlikely that bias over such long time scales arises from electromagnetic screening, but conceivable that the Lorentz force is influenced by long wavelength thermal variations and/or localized regions of increased electrical conductivity (associated with compositional anomalies and possibly partial melt). This is consistent with recent seismic observations of the lower mantle.

  11. Depolarizing field in ultrathin electrocalorics

    NASA Astrophysics Data System (ADS)

    Glazkova, E.; Chang, C.-M.; Lisenkov, S.; Mani, B. K.; Ponomareva, I.

    2015-08-01

    Ferroelectric thin films are considered to be among the top candidates for room-temperature electrocaloric materials as they exhibit excellent electric properties and allow application of record high electric fields. At the same time, downsizing of ferroelectric electrocalorics brings about an unwanted but unavoidable depolarizing field that could critically alter or even destroy the films' electrocaloric properties. We use an atomistic first-principles-based computational approach that does not rely on the use of Maxwell relations (i) to reveal the critical role of the depolarizing field on the electrocaloric properties of ferroelectric ultrathin films, (ii) to demonstrate the contribution of nanodomains to the electrocaloric effect in such films, and (iii) to revisit the potential limitations of the indirect approach to study electrocaloric effect in nanoscale ferroelectrics.

  12. The magnetic field of Jupiter

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.; Ness, N. F.

    1976-01-01

    The paper is concerned mainly with the intrinsic planetary field which dominates the inner magnetosphere up to a distance of 10 to 12 Jovian radii where other phenomena, such as ring currents and diamagnetic effects of trapped charged particles, become significant. The main magnetic field of Jupiter as determined by in-situ observations by Pioner 10 and 11 is found to be relatively more complex than a simple offset tilted dipole. Deviations from a simple dipole geometry lead to distortions of the charged particle L shells and warping of the magnetic equator. Enhanced absorption effects associated with Io and Amalthea are predicted. The results are consistent with the conclusions derived from extensive radio observations at decimetric and decametric wavelengths for the planetary field.

  13. Hybrid Shielding for Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Mullins, David; Royal, Kevin

    2017-01-01

    Precision symmetry measurements such as the search for the electric dipole moment of the neutron require magnetic shielding rooms to reduce the ambient field to the pT scale. The massive mu-metal sheets and large separation between layers make these shield rooms bulky and expensive. Active field cancellation systems used to reduce the surrounding field are limited in uniformity of cancellation. A novel approach to reducing the space between shield layers and increasing the effectiveness of active cancellation is to combine the two systems into a hybrid system, with active and passive layers interspersed. We demonstrate this idea in a prototype with an active layer sandwiched between two passive layers of shielding.

  14. Aquila field: Advanced contracting strategies

    SciTech Connect

    1997-04-01

    Aquila oil field, in 2,800 ft of water, is in the middle of the Otranto Channel in the Mediterranean Sea, approximately 28 miles offshore southern Italy, and is subject to difficult sea and weather conditions. The many difficulties, caused mainly by water depth, requires the use of advanced technology that can be obtained only through the direct association with contractor companies. This solution safeguards the technological reliability and allows for maximum control of time and cost. The selection of a floating production, storage, and offloading (FPSO) system resulted from a feasibility study that indicated this solution was the only method that would provide economical exploitation of the Aquila field. The system includes flowlines and control lines. The ship, FPSO Agip Firenze, has been specially redesigned to manage the field development. Agip will provide the subsea production system, the Christmas tree, control system, and artificial lift.

  15. Ultrasound fields in attenuating media.

    PubMed

    Lerch, R; Friedrich, W

    1986-10-01

    For medical ultrasonic imaging and for nondestructive testing, the attenuation of pressure waves and the resulting shift in wave velocity are important features in commonly used transmission media such as biological tissue. An algorithm for the numerical evaluation of pressure field distributions generated by ultrasonic transducers is presented. The attenuation and dispersion of the sound transmission medium are taken into consideration. The sound fields are computed numerically for continuous wave as well as pulse excitation. The transducer has plane or gently curved geometry and is embedded in a plane rigid baffle. The numerically determined pressure fields are presented as 3D plots, as gray-scale images for a fixed time stamp (like a snapshot), or as isobars regarding the maximum values over time for each local point in the area under investigation. The algorithm described here can be utilized as a tool for design of ultrasound transducers, especially array antennas.

  16. Galactic and Intergalactic Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Klein, U.; Fletcher, A.

    This course-tested textbook conveys the fundamentals of magnetic fields and relativistic plasma in diffuse cosmic media, with a primary focus on phenomena that have been observed at different wavelengths. Theoretical concepts are addressed wherever necessary, with derivations presented in sufficient detail to be generally accessible. In the first few chapters the authors present an introduction to various astrophysical phenomena related to cosmic magnetism, with scales ranging from molecular clouds in star-forming regions and supernova remnants in the Milky Way, to clusters of galaxies. Later chapters address the role of magnetic fields in the evolution of the interstellar medium, galaxies and galaxy clusters. The book is intended for advanced undergraduate and postgraduate students in astronomy and physics and will serve as an entry point for those starting their first research projects in the field.

  17. Background field coils for the High Field Test Facility

    SciTech Connect

    Zbasnik, J.P.; Cornish, D.N.; Scanlan, R.M.; Jewell, A.M.; Leber, R.L.; Rosdahl, A.R.; Chaplin, M.R.

    1980-09-22

    The High Field Test Facility (HFTF), presently under construction at LLNL, is a set of superconducting coils that will be used to test 1-m-o.d. coils of prototype conductors for fusion magnets in fields up to 12 T. The facility consists of two concentric sets of coils; the outer set is a stack of Nb-Ti solenoids, and the inner set is a pair of solenoids made of cryogenically-stabilized, multifilamentary Nb/sub 3/Sn superconductor, developed for use in mirror-fusion magnets. The HFTF system is designed to be parted along the midplane to allow high-field conductors, under development for Tokamak fusion machines, to be inserted and tested. The background field coils were wound pancake-fashion, with cold-welded joints at both the inner and outer diameters. Turn-to-turn insulation was fabricated at LLNL from epoxy-fiberglass strip. The coils were assembled and tested in our 2-m-diam cryostat to verify their operation.

  18. USA Track & Field Coaching Manual. USA Track & Field.

    ERIC Educational Resources Information Center

    USA Track and Field, Inc., Indianapolis, IN.

    This book presents comprehensive, ready-to-apply information from 33 world-class coaches and experts about major track and field events for high school and college coaches. The volume features proven predictive testing procedures; detailed event-specific technique instruction; carefully crafted training programs; and preparation and performance…

  19. 7 CFR 600.6 - Field offices.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Field offices. 600.6 Section 600.6 Agriculture... AGRICULTURE GENERAL ORGANIZATION § 600.6 Field offices. Each field office is under the direction and... served by the field office. Usually the geographical area of a field office includes one or...

  20. 7 CFR 600.6 - Field offices.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Field offices. 600.6 Section 600.6 Agriculture... AGRICULTURE GENERAL ORGANIZATION § 600.6 Field offices. Each field office is under the direction and... served by the field office. Usually the geographical area of a field office includes one or...

  1. 7 CFR 600.6 - Field offices.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Field offices. 600.6 Section 600.6 Agriculture... AGRICULTURE GENERAL ORGANIZATION § 600.6 Field offices. Each field office is under the direction and... served by the field office. Usually the geographical area of a field office includes one or...

  2. 7 CFR 600.6 - Field offices.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Field offices. 600.6 Section 600.6 Agriculture... AGRICULTURE GENERAL ORGANIZATION § 600.6 Field offices. Each field office is under the direction and... served by the field office. Usually the geographical area of a field office includes one or...

  3. 7 CFR 600.6 - Field offices.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Field offices. 600.6 Section 600.6 Agriculture... AGRICULTURE GENERAL ORGANIZATION § 600.6 Field offices. Each field office is under the direction and... served by the field office. Usually the geographical area of a field office includes one or...

  4. Oxide superconductors under magnetic field

    NASA Technical Reports Server (NTRS)

    Kitazawa, K.

    1990-01-01

    One of the current most serious problems for the oxide superconductors from the standpoint of practical application is the various novel features derived mainly from their extremely short coherence. In particular, the coherence length so far observed in the cuprate superconductors is in the range of 0.1 nm perpendicular to the CuO2 plane. This seems to be creating most of the difficulties in the device fabrication and in the performance under the magnetic field. Some of the superconducting properties under the magnetic field will be discussed in terms of the short coherence length. A model will be presented based on the gradual strengthening of the pinning force with decrease in temperature and the weak coupling at the grain boundaries. Secondly, the broadening of the superconducting transition under the magnetic field is discussed. This is observed significantly only when the field is applied perpendicular to the basal plane and the relative orientation of the current to the field is insignificant in determining the extent of the broadening. Besides, the change in the strength of the pinning force does not affect the width of the broadening. From these observations discussions will be made on a model based on the giant fluctuation. Based on this model, it is predicted that the coherence length along the c-axis will be the single most important material parameter to determine the performance of the superconductor under a strong magnetic field. It seems that BYCO is superior in this regard to Bi- or Tl-systems as far as the performance at 77 K is considered, although another material with the coherence length slightly longer along the c-axis is still highly desired.

  5. Oxide superconductors under magnetic field

    NASA Technical Reports Server (NTRS)

    Kitazawa, K.

    1991-01-01

    One of the current most serious problems for the oxide superconductors from the standpoint of practical application is the various novel features derived mainly from their extremely short coherence. In particular, the coherence length so far observed in the cuprate superconductors is in the range of 0.1 nm perpendicular to the CuO2 plane. This seems to be creating most of the difficulties in the device fabrication and in the performance under the magnetic field. Some of the superconducting properties under the magnetic field will be discussed in terms of the short coherence length. A model will be presented based on the gradual strengthening of the pinning force with decrease in temperature and the weak coupling at the grain boundaries. Secondly, the broadening of the superconducting transition under the magnetic field is discussed. This is observed significantly only when the field is applied perpendicular to the basal plane and the relative orientation of the current to the field is insignificant in determining the extent of broadening. Besides, the change in the strength of the pinning force does not affect the width of the broadening. From these observations discussions will be made on a model based on the giant fluctuation. Based on this model, it is predicted that the coherence length along the c-axis will be the single most important material parameter to determine the performance of the superconductor under a strong magnetic field. It seems that BYCO is superior in this regard to Bi- or Tl-systems as far as the performance at 77 K is considered, although another material with the coherence length slightly longer along the c-axis is still highly desired.

  6. Inflating with large effective fields

    SciTech Connect

    Burgess, C.P.; Cicoli, M.; Quevedo, F.; Williams, M. E-mail: mcicoli@ictp.it E-mail: mwilliams@perimeterinsititute.ca

    2014-11-01

    We re-examine large scalar fields within effective field theory, in particular focussing on the issues raised by their use in inflationary models (as suggested by BICEP2 to obtain primordial tensor modes). We argue that when the large-field and low-energy regimes coincide the scalar dynamics is most effectively described in terms of an asymptotic large-field expansion whose form can be dictated by approximate symmetries, which also help control the size of quantum corrections. We discuss several possible symmetries that can achieve this, including pseudo-Goldstone inflatons characterized by a coset G/H (based on abelian and non-abelian, compact and non-compact symmetries), as well as symmetries that are intrinsically higher dimensional. Besides the usual trigonometric potentials of Natural Inflation we also find in this way simple large-field power laws (like V ∝ φ{sup 2}) and exponential potentials, V(φ) = ∑{sub k}V{sub x}e{sup −kφ/M}. Both of these can describe the data well and give slow-roll inflation for large fields without the need for a precise balancing of terms in the potential. The exponential potentials achieve large r through the limit |η| || ε and so predict r ≅ (8/3)(1-n{sub s}); consequently n{sub s} ≅ 0.96 gives r ≅ 0.11 but not much larger (and so could be ruled out as measurements on r and n{sub s} improve). We examine the naturalness issues for these models and give simple examples where symmetries protect these forms, using both pseudo-Goldstone inflatons (with non-abelian non-compact shift symmetries following familiar techniques from chiral perturbation theory) and extra-dimensional models.

  7. Introduction to Vector Field Visualization

    NASA Technical Reports Server (NTRS)

    Kao, David; Shen, Han-Wei

    2010-01-01

    Vector field visualization techniques are essential to help us understand the complex dynamics of flow fields. These can be found in a wide range of applications such as study of flows around an aircraft, the blood flow in our heart chambers, ocean circulation models, and severe weather predictions. The vector fields from these various applications can be visually depicted using a number of techniques such as particle traces and advecting textures. In this tutorial, we present several fundamental algorithms in flow visualization including particle integration, particle tracking in time-dependent flows, and seeding strategies. For flows near surfaces, a wide variety of synthetic texture-based algorithms have been developed to depict near-body flow features. The most common approach is based on the Line Integral Convolution (LIC) algorithm. There also exist extensions of LIC to support more flexible texture generations for 3D flow data. This tutorial reviews these algorithms. Tensor fields are found in several real-world applications and also require the aid of visualization to help users understand their data sets. Examples where one can find tensor fields include mechanics to see how material respond to external forces, civil engineering and geomechanics of roads and bridges, and the study of neural pathway via diffusion tensor imaging. This tutorial will provide an overview of the different tensor field visualization techniques, discuss basic tensor decompositions, and go into detail on glyph based methods, deformation based methods, and streamline based methods. Practical examples will be used when presenting the methods; and applications from some case studies will be used as part of the motivation.

  8. Pulsed electric field increases reproduction.

    PubMed

    Panagopoulos, Dimitris J

    2016-01-01

    Purpose To study the effect of pulsed electric field - applied in corona discharge photography - on Drosophila melanogaster reproduction, possible induction of DNA fragmentation, and morphological alterations in the gonads. Materials and methods Animals were exposed to different field intensities (100, 200, 300, and 400 kV/m) during the first 2-5 days of their adult lives, and the effect on reproductive capacity was assessed. DNA fragmentation during early- and mid-oogenesis was investigated by application of the TUNEL (Terminal deoxynucleotide transferase dUTP Nick End Labeling) assay. Sections of follicles after fixation and embedding in resins were observed for possible morphological/developmental abnormalities. Results The field increased reproduction by up to 30% by increasing reproductive capacity in both sexes. The effect increased with increasing field intensities. The rate of increase diminished at the strongest intensities. Slight induction of DNA fragmentation was observed exclusively in the nurse (predominantly) and follicle cells, and exclusively at the two most sensitive developmental stages, i.e., germarium and predominantly stage 7-8. Sections of follicles from exposed females at stages of early and mid-oogennesis other than germarium and stages 7-8 did not reveal abnormalities. Conclusions (1) The specific type of electric field may represent a mild stress factor, inducing DNA fragmentation and cell death in a small percentage of gametes, triggering the reaction of the animal's reproductive system to increase the rate of gametogenesis in order to compensate the loss of a small number of gametes. (2) The nurse cells are the most sensitive from all three types of egg chamber cells. (3) The mid-oogenesis checkpoint (stage 7-8) is more sensitive to this field than the early oogenesis one (germarium) in contrast to microwave exposure. (4) Possible therapeutic applications, or applications in increasing fertility, should be investigated.

  9. Sensitivity to volcanic field boundary

    NASA Astrophysics Data System (ADS)

    Runge, Melody; Bebbington, Mark; Cronin, Shane; Lindsay, Jan; Rashad Moufti, Mohammed

    2016-04-01

    Volcanic hazard analyses are desirable where there is potential for future volcanic activity to affect a proximal population. This is frequently the case for volcanic fields (regions of distributed volcanism) where low eruption rates, fertile soil, and attractive landscapes draw populations to live close by. Forecasting future activity in volcanic fields almost invariably uses spatial or spatio-temporal point processes with model selection and development based on exploratory analyses of previous eruption data. For identifiability reasons, spatio-temporal processes, and practically also spatial processes, the definition of a spatial region is required to which volcanism is confined. However, due to the complex and predominantly unknown sub-surface processes driving volcanic eruptions, definition of a region based solely on geological information is currently impossible. Thus, the current approach is to fit a shape to the known previous eruption sites. The class of boundary shape is an unavoidable subjective decision taken by the forecaster that is often overlooked during subsequent analysis of results. This study shows the substantial effect that this choice may have on even the simplest exploratory methods for hazard forecasting, illustrated using four commonly used exploratory statistical methods and two very different regions: the Auckland Volcanic Field, New Zealand, and Harrat Rahat, Kingdom of Saudi Arabia. For Harrat Rahat, sensitivity of results to boundary definition is substantial. For the Auckland Volcanic Field, the range of options resulted in similar shapes, nevertheless, some of the statistical tests still showed substantial variation in results. This work highlights the fact that when carrying out any hazard analysis on volcanic fields, it is vital to specify how the volcanic field boundary has been defined, assess the sensitivity of boundary choice, and to carry these assumptions and related uncertainties through to estimates of future activity and

  10. The North Carolina Field Test

    SciTech Connect

    Sharp, T.R.; Ternes, M.P.

    1990-08-01

    The North Carolina Field Test will test the effectiveness of two weatherization approaches: the current North Carolina Low-Income Weatherization Assistance Program and the North Carolina Field Test Audit. The Field Test Audit will differ from North Carolina's current weatherization program in that it will incorporate new weatherization measures and techniques, a procedure for basing measure selection of the characteristics of the individual house and the cost-effectiveness of the measure, and also emphasize cooling energy savings. The field test will determine the differences of the two weatherization approaches from the viewpoints of energy savings, cost effectiveness, and implementation ease. This Experimental Plan details the steps in performing the field test. The field test will be a group effort by several participating organizations. Pre- and post-weatherization data will be collected over a two-year period (November 1989 through August 1991). The 120 houses included in the test will be divided into a control group and two treatment groups (one for each weatherization procedure) of 40 houses each. Weekly energy use data will be collected for each house representing whole-house electric, space heating and cooling, and water heating energy uses. Corresponding outdoor weather and house indoor temperature data will also be collected. The energy savings of each house will be determined using linear-regression based models. To account for variations between the pre- and post-weatherization periods, house energy savings will be normalized for differences in outdoor weather conditions and indoor temperatures. Differences between the average energy savings of treatment groups will be identified using an analysis of variance approach. Differences between energy savings will be quantified using multiple comparison techniques. 9 refs., 8 figs., 5 tabs.

  11. Variational methods for field theories

    SciTech Connect

    Ben-Menahem, S.

    1986-09-01

    Four field theory models are studied: Periodic Quantum Electrodynamics (PQED) in (2 + 1) dimensions, free scalar field theory in (1 + 1) dimensions, the Quantum XY model in (1 + 1) dimensions, and the (1 + 1) dimensional Ising model in a transverse magnetic field. The last three parts deal exclusively with variational methods; the PQED part involves mainly the path-integral approach. The PQED calculation results in a better understanding of the connection between electric confinement through monopole screening, and confinement through tunneling between degenerate vacua. This includes a better quantitative agreement for the string tensions in the two approaches. Free field theory is used as a laboratory for a new variational blocking-truncation approximation, in which the high-frequency modes in a block are truncated to wave functions that depend on the slower background modes (Boron-Oppenheimer approximation). This ''adiabatic truncation'' method gives very accurate results for ground-state energy density and correlation functions. Various adiabatic schemes, with one variable kept per site and then two variables per site, are used. For the XY model, several trial wave functions for the ground state are explored, with an emphasis on the periodic Gaussian. A connection is established with the vortex Coulomb gas of the Euclidean path integral approach. The approximations used are taken from the realms of statistical mechanics (mean field approximation, transfer-matrix methods) and of quantum mechanics (iterative blocking schemes). In developing blocking schemes based on continuous variables, problems due to the periodicity of the model were solved. Our results exhibit an order-disorder phase transition. The transfer-matrix method is used to find a good (non-blocking) trial ground state for the Ising model in a transverse magnetic field in (1 + 1) dimensions.

  12. Magnetic field of the Earth

    NASA Astrophysics Data System (ADS)

    Popov, Aleksey

    2013-04-01

    The magnetic field of the Earth has global meaning for a life on the Earth. The world geophysical science explains: - occurrence of a magnetic field of the Earth it is transformation of kinetic energy of movements of the fused iron in the liquid core of Earth - into the magnetic energy; - the warming up of a kernel of the Earth occurs due to radioactive disintegration of elements, with excretion of thermal energy. The world science does not define the reasons: - drift of a magnetic dipole on 0,2 a year to the West; - drift of lithospheric slabs and continents. The author offers: an alternative variant existing in a world science the theories "Geodynamo" - it is the theory « the Magnetic field of the Earth », created on the basis of physical laws. Education of a magnetic field of the Earth occurs at moving the electric charge located in a liquid kernel, at rotation of the Earth. At calculation of a magnetic field is used law the Bio Savara for a ring electric current: dB = . Magnetic induction in a kernel of the Earth: B = 2,58 Gs. According to the law of electromagnetic induction the Faradey, rotation of a iron kernel of the Earth in magnetic field causes occurrence of an electric field Emf which moves electrons from the center of a kernel towards the mantle. So of arise the radial electric currents. The magnetic field amplifies the iron of mantle and a kernel of the Earth. As a result of action of a radial electric field the electrons will flow from the center of a kernel in a layer of an electric charge. The central part of a kernel represents the field with a positive electric charge, which creates inverse magnetic field Binv and Emfinv When ?mfinv = ?mf ; ?inv = B, there will be an inversion a magnetic field of the Earth. It is a fact: drift of a magnetic dipole of the Earth in the western direction approximately 0,2 longitude, into a year. Radial electric currents a actions with the basic magnetic field of a Earth - it turn a kernel. It coincides with laws

  13. Quantum Field Theory, Revised Edition

    NASA Astrophysics Data System (ADS)

    Mandl, F.; Shaw, G.

    1994-01-01

    Quantum Field Theory Revised Edition F. Mandl and G. Shaw, Department of Theoretical Physics, The Schuster Laboratory, The University, Manchester, UK When this book first appeared in 1984, only a handful of W± and Z° bosons had been observed and the experimental investigation of high energy electro-weak interactions was in its infancy. Nowadays, W± bosons and especially Z° bosons can be produced by the thousand and the study of their properties is a precise science. We have revised the text of the later chapters to incorporate these developments and discuss their implications. We have also taken this opportunity to update the references throughout and to make some improvements in the treatment of dimen-sional regularization. Finally, we have corrected some minor errors and are grateful to various people for pointing these out. This book is designed as a short and simple introduction to quantum field theory for students beginning research in theoretical and experimental physics. The three main objectives are to explain the basic physics and formalism of quantum field theory, to make the reader fully proficient in theory calculations using Feynman diagrams, and to introduce the reader to gauge theories, which play such a central role in elementary particle physics. The theory is applied to quantum electrodynamics (QED), where quantum field theory had its early triumphs, and to weak interactions where the standard electro-weak theory has had many impressive successes. The treatment is based on the canonical quantization method, because readers will be familiar with this, because it brings out lucidly the connection between invariance and conservation laws, and because it leads directly to the Feynman diagram techniques which are so important in many branches of physics. In order to help inexperienced research students grasp the meaning of the theory and learn to handle it confidently, the mathematical formalism is developed from first principles, its physical

  14. Near Field Antenna Measurement System.

    DTIC Science & Technology

    1982-03-01

    beam pointing accuracy and .6 dB gain accuracy. These antennas are both planar arrays with the X-band antenna scanning with ferrite phase shifters in...AD-A114 125 M[ES AIRCRAFT CO FULLERTON CA F/ 17/9 NEAR FIELD ANTENNA MEASUREMENT SYSTEM. (U) MAR 82 A E HOLLEY DAABO7-7?-C-1 87 UNCLASSIFIED NL...IllIHE El. onhEnoh IIIIhh --h h I~m I I Research and Development Technical Report I DAABO7-77-C-0587-F1 NEAR FIELD ANTENNA I MEASUREMENT SYSTEM I A.E

  15. Wide field of view telescope

    DOEpatents

    Ackermann, Mark R.; McGraw, John T.; Zimmer, Peter C.

    2008-01-15

    A wide field of view telescope having two concave and two convex reflective surfaces, each with an aspheric surface contour, has a flat focal plane array. Each of the primary, secondary, tertiary, and quaternary reflective surfaces are rotationally symmetric about the optical axis. The combination of the reflective surfaces results in a wide field of view in the range of approximately 3.8.degree. to approximately 6.5.degree.. The length of the telescope along the optical axis is approximately equal to or less than the diameter of the largest of the reflective surfaces.

  16. Solid phase microextraction field kit

    DOEpatents

    Nunes, Peter J.; Andresen, Brian D.

    2005-08-16

    A field kit for the collection, isolation and concentration of trace amounts of high explosives (HE), biological weapons (BW) and chemical weapons (CW) residues in air, soil, vegetation, swipe, and liquid samples. The field kit includes a number of Solid Phase Microextraction (SPME) fiber and syringe assemblies in a hermetically sealed transportation container or tubes which includes a sampling port, a number of extra SPME fiber and syringe assemblies, the fiber and syringe assemblies including a protective cap for the fiber, and an extractor for the protective cap, along with other items including spare parts, protective glove, and an instruction manual, all located in an airtight container.

  17. Particles, Fields, and Gravitation. Proceedings

    SciTech Connect

    Rembieli ski, J.

    1998-11-01

    These proceedings represent papers presented at the Conference on Particles, Fields, and Gravitation held in Lodz, Poland in April, 1998. The topics discussed included quantum deformations and noncommutative geometry, quantum mechanics, quantum and topological field theory, modern gravitation theory and geometrical methods in physics. Solvable and quasisolvable models were also disussed. The talks and the resulting papers provided a comprehensive coverage of the main aspects of contemporary theoretical and mathematical physics. The Conference was attended by more than 100 scientists from all over the world. There were 54 papers presented at the conference,out of which 1 paper has been abstracted for the Energy,Science and Technology database.(AIP)

  18. On supersymmetric Lifshitz field theories

    NASA Astrophysics Data System (ADS)

    Chapman, Shira; Oz, Yaron; Raviv-Moshe, Avia

    2015-10-01

    We consider field theories that exhibit a supersymmetric Lifshitz scaling with two real supercharges. The theories can be formulated in the language of stochastic quan-tization. We construct the free field supersymmetry algebra with rotation singlet fermions for an even dynamical exponent z = 2 k in an arbitrary dimension. We analyze the classical and quantum z = 2 supersymmetric interactions in 2 + 1 and 3 + 1 spacetime dimensions and reveal a supersymmetry preserving quantum diagrammatic cancellation. Stochastic quantization indicates that Lifshitz scale invariance is broken in the (3 + 1)-dimensional quantum theory.

  19. Electromagnetic Field Effects in Explosives

    NASA Astrophysics Data System (ADS)

    Tasker, D. G.; Whitley, V. H.; Lee, R. J.

    2009-12-01

    Present and previous research on the effects of electromagnetic fields on the initiation and detonation of explosives and the electromagnetic properties of explosives are reviewed. Among the topics related to detonating explosives are: enhancement of performance; and control of initiation and growth of reaction. Two series of experiments were performed to determine the effects of 1-T magnetic fields on explosive initiation and growth in the modified gap test and on the propagation of explosively generated plasma into air. The results have implications for the control of reactions in explosives and for the use of electromagnetic particle velocity gauges.

  20. Dynamics of gauge field inflation

    SciTech Connect

    Alexander, Stephon; Jyoti, Dhrubo; Kosowsky, Arthur; Marcianò, Antonino

    2015-05-05

    We analyze the existence and stability of dynamical attractor solutions for cosmological inflation driven by the coupling between fermions and a gauge field. Assuming a spatially homogeneous and isotropic gauge field and fermion current, the interacting fermion equation of motion reduces to that of a free fermion up to a phase shift. Consistency of the model is ensured via the Stückelberg mechanism. We prove the existence of exactly one stable solution, and demonstrate the stability numerically. Inflation arises without fine tuning, and does not require postulating any effective potential or non-standard coupling.

  1. Synaptic Effects of Electric Fields

    NASA Astrophysics Data System (ADS)

    Rahman, Asif

    Learning and sensory processing in the brain relies on the effective transmission of information across synapses. The strength and efficacy of synaptic transmission is modifiable through training and can be modulated with noninvasive electrical brain stimulation. Transcranial electrical stimulation (TES), specifically, induces weak intensity and spatially diffuse electric fields in the brain. Despite being weak, electric fields modulate spiking probability and the efficacy of synaptic transmission. These effects critically depend on the direction of the electric field relative to the orientation of the neuron and on the level of endogenous synaptic activity. TES has been used to modulate a wide range of neuropsychiatric indications, for various rehabilitation applications, and cognitive performance in diverse tasks. How can a weak and diffuse electric field, which simultaneously polarizes neurons across the brain, have precise changes in brain function? Designing therapies to maximize desired outcomes and minimize undesired effects presents a challenging problem. A series of experiments and computational models are used to define the anatomical and functional factors leading to specificity of TES. Anatomical specificity derives from guiding current to targeted brain structures and taking advantage of the direction-sensitivity of neurons with respect to the electric field. Functional specificity originates from preferential modulation of neuronal networks that are already active. Diffuse electric fields may recruit connected brain networks involved in a training task and promote plasticity along active synaptic pathways. In vitro, electric fields boost endogenous synaptic plasticity and raise the ceiling for synaptic learning with repeated stimulation sessions. Synapses undergoing strong plasticity are preferentially modulated over weak synapses. Therefore, active circuits that are involved in a task could be more susceptible to stimulation than inactive circuits

  2. Entropic quantization of scalar fields

    SciTech Connect

    Ipek, Selman; Caticha, Ariel

    2015-01-13

    Entropic Dynamics is an information-based framework that seeks to derive the laws of physics as an application of the methods of entropic inference. The dynamics is derived by maximizing an entropy subject to constraints that represent the physically relevant information that the motion is continuous and non-dissipative. Here we focus on the quantum theory of scalar fields. We provide an entropic derivation of Hamiltonian dynamics and using concepts from information geometry derive the standard quantum field theory in the Schrödinger representation.

  3. The Quantum Theory of Fields

    NASA Astrophysics Data System (ADS)

    Weinberg, Steven

    1996-08-01

    In this second volume of The Quantum Theory of Fields, available for the first time in paperback, Nobel Laureate Steven Weinberg continues his masterly expoistion of quantum theory. Volume 2 provides an up-to-date and self-contained account of the methods of quantum field theory, and how they have led to an understanding of the weak, strong, and electromagnetic interactions of the elementary particles. The presentation of modern mathematical methods is throughout interwoven with accounts of the problems of elementary particle physics and condensed matter physics to which they have been applied. Exercises are included at the end of each chapter.

  4. The HMI Magnetic Field Pipeline

    NASA Astrophysics Data System (ADS)

    Hoeksema, Jon Todd; Liu, Y.; Schou, J.; Scherrer, P.; HMI Science Team

    2009-05-01

    The Helioseismic and Magnetic Imager (HMI) will provide frequent full-disk magnetic field data after launch of the Solar Dynamics Observatory (SDO), currently scheduled for fall 2009. 16 megapixel line-of-sight magnetograms (Blos) will be recorded every 45 seconds. A full set of polarized filtergrams needed to determine the vector magnetic field requires 90 seconds. Quick-look data will be available within a few minutes of observation. Quick-look space weather and browse products must have identified users, and the list currently includes full disk magnetograms, feature identification and movies, 12-minute disambiguated vector fields in active region patches, time evolution of AR indices, synoptic synchronic frames, potential and MHD model results, and 1 AU predictions. A more complete set of definitive science data products will be offered about a day later and come in three types. "Pipeline” products, such as full disk vector magnetograms, will be computed for all data on an appropriate cadence. A larger menu of "On Demand” products, such as Non-Linear Force Free Field snapshots of an evolving active region, will be produced whenever a user wants them. Less commonly needed "On Request” products that require significant project resources, such as a high resolution MHD simulation of the global corona, will be created subject to availability of resources. Further information can be found at the SDO Joint Science Operations Center web page, jsoc.stanford.edu

  5. FIELD SAMPLING PROTOCOLS AND ANALYSIS

    EPA Science Inventory

    I have been asked to speak again to the environmental science class regarding actual research scenarios related to my work at Kerr Lab. I plan to discuss sampling protocols along with various field analyses performed during sampling activities. Many of the students have never see...

  6. Spin-one matter fields

    NASA Astrophysics Data System (ADS)

    Napsuciale, M.; Rodríguez, S.; Ferro-Hernández, Rodolfo; Gómez-Ávila, Selim

    2016-04-01

    Spin-one matter fields are relevant both for the description of hadronic states and as potential extensions of the Standard Model. In this work we present a formalism for the description of massive spin-one fields transforming in the (1 ,0 )⊕(0 ,1 ) representation of the Lorentz group, based on the covariant projection onto parity eigenspaces and Poincaré orbits. The formalism yields a constrained dynamics. We solve the constraints and perform the canonical quantization accordingly. This formulation uses the recent construction of a parity-based covariant basis for matrix operators acting on the (j ,0 )⊕(0 ,j ) representations. The algebraic properties of the covariant basis play an important role in solving the constraints and allowing the canonical quantization of the theory. We study the chiral structure of the theory and conclude that it is not chirally symmetric in the massless limit, hence it is not possible to have chiral gauge interactions. However, spin-one matter fields can have vector gauge interactions. Also, the dimension of the field makes self-interactions naively renormalizable. Using the covariant basis, we classify all possible self-interaction terms.

  7. Learning That Lasts: Field Guide

    ERIC Educational Resources Information Center

    Education Commission of the States, 2005

    2005-01-01

    This "Learning That Lasts Field Guide" is intended to trigger discussion about ways to integrate and sustain high-quality service-learning, as well as to provide a clearer path to finding and employing the information in the Education Commission of the States' (ECS) 2002 publication "Learning That Lasts: How Service-Learning Can Become an Integral…

  8. The Theory of Conceptual Fields

    ERIC Educational Resources Information Center

    Vergnaud, Gerard

    2009-01-01

    The theory of conceptual fields is a developmental theory. It has two aims: (1) to describe and analyse the progressive complexity, on a long- and medium-term basis, of the mathematical competences that students develop inside and outside school, and (2) to establish better connections between the operational form of knowledge, which consists in…

  9. Field sampling and travel report

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dr. Sigua was involved with two field visits of watersheds with different livestock production systems (poultry, swine, and beef/dairy cattle); one in the sub-basins of Pinhal River Watershed (October 23, 2008) and at the micro-basins of the Rio Pine Forest (October 29, 2008) where studies of assess...

  10. Particle and flow field holography

    NASA Astrophysics Data System (ADS)

    Trolinger, J. D.

    1985-01-01

    The current status of particle field and flow field holography is examined, and the methods based on the principles of either class of imagery are described. Special consideration is given to the automated data reduction technology. Current applications of flow diagnostics, which can provide thousands of holograms during a one-day experiment, include NASA applications in wind tunnel holography, in a Laser Doppler Velocimeter, in holographic movies, and in an optical device for recording crystal growth at zero gravity, to be used in the Space Lab 3 shuttle mission scheduled for May 1985. Military applications of the flow diagnostics include the use of holographic tomography for visualizing flow fields around airborne structures, in wind tunnels, and in the analyses of rocket exhausts and gun ranges. The information provided by the particle sizing holography, concerning the size, shape, number, and velocity of particles and the records of the particle break-up phenomenon, can be used in various military field oriented and airborne applications and in meteorology and environment protection science.

  11. Dynamic properties of force fields

    NASA Astrophysics Data System (ADS)

    Vitalini, F.; Mey, A. S. J. S.; Noé, F.; Keller, B. G.

    2015-02-01

    Molecular-dynamics simulations are increasingly used to study dynamic properties of biological systems. With this development, the ability of force fields to successfully predict relaxation timescales and the associated conformational exchange processes moves into focus. We assess to what extent the dynamic properties of model peptides (Ac-A-NHMe, Ac-V-NHMe, AVAVA, A10) differ when simulated with different force fields (AMBER ff99SB-ILDN, AMBER ff03, OPLS-AA/L, CHARMM27, and GROMOS43a1). The dynamic properties are extracted using Markov state models. For single-residue models (Ac-A-NHMe, Ac-V-NHMe), the slow conformational exchange processes are similar in all force fields, but the associated relaxation timescales differ by up to an order of magnitude. For the peptide systems, not only the relaxation timescales, but also the conformational exchange processes differ considerably across force fields. This finding calls the significance of dynamic interpretations of molecular-dynamics simulations into question.

  12. Magnetostatic Surface Field Measurement Facility.

    DTIC Science & Technology

    1986-12-01

    8217*. . - .J ., TV el VV TV - UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE REPORT DOCUMENTATION PA~a El la REPCRT SECURITY CLASSIFICAT ION lb...0 10 -YW 977 the sI;eroid relative to the incident magnetic field, it is convenient to cons’der seoarately the cases when H- z = 0 and Hi z = 1

  13. Nanomanipulation using near field photonics.

    PubMed

    Erickson, David; Serey, Xavier; Chen, Yih-Fan; Mandal, Sudeep

    2011-03-21

    In this article we review the use of near-field photonics for trapping, transport and handling of nanomaterials. While the advantages of traditional optical tweezing are well known at the microscale, direct application of these techniques to the handling of nanoscale materials has proven difficult due to unfavourable scaling of the fundamental physics. Recently a number of research groups have demonstrated how the evanescent fields surrounding photonic structures like photonic waveguides, optical resonators, and plasmonic nanoparticles can be used to greatly enhance optical forces. Here, we introduce some of the most common implementations of these techniques, focusing on those which have relevance to microfluidic or optofluidic applications. Since the field is still relatively nascent, we spend much of the article laying out the fundamental and practical advantages that near field optical manipulation offers over both traditional optical tweezing and other particle handling techniques. In addition we highlight three application areas where these techniques namely could be of interest to the lab-on-a-chip community, namely: single molecule analysis, nanoassembly, and optical chromatography.

  14. Explanations, Education, and Electromagnetic Fields.

    ERIC Educational Resources Information Center

    Friedman, Sharon M.

    Explaining complex scientific and environmental subjects in the mass media is difficult to do, particularly under such constraints as short deadlines and lack of space or time. When a scientific controversy and human health risk are involved, this becomes an even harder task to accomplish. The subject of electromagnetic fields (EMF) involves…

  15. Research in particles and fields

    NASA Technical Reports Server (NTRS)

    Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

    1984-01-01

    The astrophysical aspects of cosmic rays and gamma rays and of the electromagnetic field environment of the Earth and other planets are investigated. These investigations are carried out by means of energetic particle and photon detector systems flown on spacecraft and balloons.

  16. Visual Learning in Field Biology.

    ERIC Educational Resources Information Center

    Stanley, Ethel D.

    Visual learning has long been recognized as an integral process in educating biology undergraduates, who must develop specific visual skills and knowledge in order to communicate and work in the extensive visual culture shared by practicing biologists. Student experiences with field observations and the development and application of verbal/visual…

  17. A Mineral Processing Field Course

    ERIC Educational Resources Information Center

    Carmody, Maurice

    2014-01-01

    This article describes a field course in Cornwall looking at mineral processing with the focus on the chemistry involved. The course was split into two parts. The first looked at tin mining based around Penzance. This involved visiting mines, hunting for mineral samples, carrying out a stream survey and visiting the Camborne School of Mines…

  18. Evaluating cotton stripper field performance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton strippers are used primarily in the Southern High Plains due to the specific cotton varieties grown. Typically, cotton strippers cost about two-thirds the price of a cotton picker and range from one-half to one-fourth the horsepower. A cotton stripper also has a higher field and harvesting ef...

  19. Linear electric field mass spectrometry

    DOEpatents

    McComas, D.J.; Nordholt, J.E.

    1992-12-01

    A mass spectrometer and methods for mass spectrometry are described. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field. 8 figs.

  20. Linear electric field mass spectrometry

    DOEpatents

    McComas, David J.; Nordholt, Jane E.

    1992-01-01

    A mass spectrometer and methods for mass spectrometry. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field.

  1. Physical Education: A Professional Field.

    ERIC Educational Resources Information Center

    O'Hanlon, James; Wandzilak, Thomas

    1980-01-01

    Although some effort has been expended toward the development of physical education as a discipline, the nature of physical education reveals that it is more a professional field. A model is described which provides a means to draw from several contributing disciplines and subdisciplines in order to improve the practice of physical education.…

  2. FIELD DEMONSTRATION AND QUALITY ASSURANCE ...

    EPA Pesticide Factsheets

    The Demonstration of innovative field devices for the measurement of mercury in soil and sediment is being conducted under the EPA's SITE Program in February 2003 at the United States Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee and the Tennessee Department of Environment and Conservation's Department of Energy Oversight facility in Oak Ridge, Tennessee. The primary purpose of the Demonstration is to evaluate innovative field devices for the measurement of mercury in soil and sediment based on their performance and cost as compared to a conventional, off-site laboratory analytical method. The five field measurement devices listed below will be demonstrated: .Metorex's X-M ET 2000 Metal Master Analyzer, X-Ray Fluorescence Analyzer .Milestone Inc.'s Direct Mercury Analyzer (DMA-80), Thermal Decomposition Instrument.NITON's XL-700 Series Multi-Element Analyzer, X-Ray Fluorescence Analyzer .Ohio Lumex's RA-915+ Portable Mercury Analyzer, Atomic Absorption Spectrometer, Thermal Decompostion Attachment RP 91C .MTI, Inc.'s PDV 5000 Hand Held Instrument, Anodic Stripping Voltamm eter<1). This Demonstration Plan describes the procedures that will be used to verify the performance and cost of each field measurement device. The plan incorporates the quality assurance and quality control elements needed to generate data of sufficient quality to document each device's performance and cost. A separate Innovative Technology Verifica

  3. Field induced gap infrared detector

    NASA Technical Reports Server (NTRS)

    Elliott, C. Thomas (Inventor)

    1990-01-01

    A tunable infrared detector which employs a vanishing band gap semimetal material provided with an induced band gap by a magnetic field to allow intrinsic semiconductor type infrared detection capabilities is disclosed. The semimetal material may thus operate as a semiconductor type detector with a wavelength sensitivity corresponding to the induced band gap in a preferred embodiment of a diode structure. Preferred semimetal materials include Hg(1-x)Cd(x)Te, x is less than 0.15, HgCdSe, BiSb, alpha-Sn, HgMgTe, HgMnTe, HgZnTe, HgMnSe, HgMgSe, and HgZnSe. The magnetic field induces a band gap in the semimetal material proportional to the strength of the magnetic field allowing tunable detection cutoff wavelengths. For an applied magnetic field from 5 to 10 tesla, the wavelength detection cutoff will be in the range of 20 to 50 micrometers for Hg(1-x)Cd(x)Te alloys with x about 0.15. A similar approach may also be employed to generate infrared energy in a desired band gap and then operating the structure in a light emitting diode or semiconductor laser type of configuration.

  4. Wide-Field Plate Database

    NASA Astrophysics Data System (ADS)

    Tsvetkov, M. K.; Stavrev, K. Y.; Tsvetkova, K. P.; Semkov, E. H.; Mutatov, A. S.

    The Wide-Field Plate Database (WFPDB) and the possibilities for its application as a research tool in observational astronomy are presented. Currently the WFPDB comprises the descriptive data for 400 000 archival wide field photographic plates obtained with 77 instruments, from a total of 1 850 000 photographs stored in 269 astronomical archives all over the world since the end of last century. The WFPDB is already accessible for the astronomical community, now only in batch mode through user requests sent by e-mail. We are working on on-line interactive access to the data via INTERNET from Sofia and parallel from the Centre de Donnees Astronomiques de Strasbourg. (Initial information can be found on World Wide Web homepage URL http://www.wfpa.acad.bg.) The WFPDB may be useful in studies of a variety of astronomical objects and phenomena, andespecially for long-term investigations of variable objects and for multi-wavelength research. We have analysed the data in the WFPDB in order to derive the overall characteristics of the totality of wide-field observations, such as the sky coverage, the distributions by observation time and date, by spectral band, and by object type. We have also examined the totality of wide-field observations from point of view of their quality, availability and digitisation. The usefulness of the WFPDB is demonstrated by the results of identification and investigation of the photometrical behaviour of optical analogues of gamma-ray bursts.

  5. Electric field divertor plasma pump

    DOEpatents

    Schaffer, M.J.

    1994-10-04

    An electric field plasma pump includes a toroidal ring bias electrode positioned near the divertor strike point of a poloidal divertor of a tokamak, or similar plasma-confining apparatus. For optimum plasma pumping, the separatrix of the poloidal divertor contacts the ring electrode, which then also acts as a divertor plate. A plenum or other duct near the electrode includes an entrance aperture open to receive electrically-driven plasma. The electrode is insulated laterally with insulators, one of which is positioned opposite the electrode at the entrance aperture. An electric field E is established between the ring electrode and a vacuum vessel wall, with the polarity of the bias applied to the electrode being relative to the vessel wall selected such that the resultant electric field E interacts with the magnetic field B already existing in the tokamak to create an E [times] B/B[sup 2] drift velocity that drives plasma into the entrance aperture. The pumped plasma flow into the entrance aperture is insensitive to variations, intentional or otherwise, of the pump and divertor geometry. Pressure buildups in the plenum or duct connected to the entrance aperture in excess of 10 mtorr are achievable. 11 figs.

  6. Electric field divertor plasma pump

    DOEpatents

    Schaffer, Michael J.

    1994-01-01

    An electric field plasma pump includes a toroidal ring bias electrode (56) positioned near the divertor strike point of a poloidal divertor of a tokamak (20), or similar plasma-confining apparatus. For optimum plasma pumping, the separatrix (40) of the poloidal divertor contacts the ring electrode (56), which then also acts as a divertor plate. A plenum (54) or other duct near the electrode (56) includes an entrance aperture open to receive electrically-driven plasma. The electrode (56) is insulated laterally with insulators (63,64), one of which (64) is positioned opposite the electrode at the entrance aperture. An electric field E is established between the ring electrode (56) and a vacuum vessel wall (22), with the polarity of the bias applied to the electrode being relative to the vessel wall selected such that the resultant electric field E interacts with the magnetic field B already existing in the tokamak to create an E.times.B/B.sup.2 drift velocity that drives plasma into the entrance aperture. The pumped plasma flow into the entrance aperture is insensitive to variations, intentional or otherwise, of the pump and divertor geometry. Pressure buildups in the plenum or duct connected to the entrance aperture in excess of 10 mtorr are achievable.

  7. Quantization of higher spin fields

    SciTech Connect

    Wagenaar, J. W.; Rijken, T. A

    2009-11-15

    In this article we quantize (massive) higher spin (1{<=}j{<=}2) fields by means of Dirac's constrained Hamilton procedure both in the situation were they are totally free and were they are coupled to (an) auxiliary field(s). A full constraint analysis and quantization is presented by determining and discussing all constraints and Lagrange multipliers and by giving all equal times (anti)commutation relations. Also we construct the relevant propagators. In the free case we obtain the well-known propagators and show that they are not covariant, which is also well known. In the coupled case we do obtain covariant propagators (in the spin-3/2 case this requires b=0) and show that they have a smooth massless limit connecting perfectly to the massless case (with auxiliary fields). We notice that in our system of the spin-3/2 and spin-2 case the massive propagators coupled to conserved currents only have a smooth limit to the pure massless spin-propagator, when there are ghosts in the massive case.

  8. Organizational Relocation: A Field Perspective.

    DTIC Science & Technology

    1980-11-01

    economy -- the only possible basis of a long-term survival system. This thrust gene - rates expansion in detailed planning requirements. Coordination...UNCLASSIFIED Dobson, William C. Jr., and Edwin H. Harris, Jr. ranizational Relocation: A Field Perspective. North Carolina Department of Cime Control

  9. Field Agent Activities: Level 1.

    ERIC Educational Resources Information Center

    Gussett, James

    One of a series of monographs providing information about the Delaware Model: A Systems Approach to Science Education (Del Mod System), this monograph describes the role of field agents. These agents are responsible for individual teachers who express a desire for involvement in improving teacher effectiveness and to be involved in the teaching of…

  10. Noncommutative Quantum Scalar Field Cosmology

    SciTech Connect

    Diaz Barron, L. R.; Lopez-Dominguez, J. C.; Sabido, M.; Yee, C.

    2010-07-12

    In this work we study noncommutative Friedmann-Robertson-Walker (FRW) cosmology coupled to a scalar field endowed with an exponential potential. The quantum scenario is analyzed in the Bohmian formalism of quantum trajectories to investigate the effects of noncommutativity in the evolution of the universe.

  11. The Brownian mean field model

    NASA Astrophysics Data System (ADS)

    Chavanis, Pierre-Henri

    2014-05-01

    We discuss the dynamics and thermodynamics of the Brownian mean field (BMF) model which is a system of N Brownian particles moving on a circle and interacting via a cosine potential. It can be viewed as the canonical version of the Hamiltonian mean field (HMF) model. The BMF model displays a second order phase transition from a homogeneous phase to an inhomogeneous phase below a critical temperature T c = 1 / 2. We first complete the description of this model in the mean field approximation valid for N → +∞. In the strong friction limit, the evolution of the density towards the mean field Boltzmann distribution is governed by the mean field Smoluchowski equation. For T < T c , this equation describes a process of self-organization from a non-magnetized (homogeneous) phase to a magnetized (inhomogeneous) phase. We obtain an analytical expression for the temporal evolution of the magnetization close to T c . Then, we take fluctuations (finite N effects) into account. The evolution of the density is governed by the stochastic Smoluchowski equation. From this equation, we derive a stochastic equation for the magnetization and study its properties both in the homogenous and inhomogeneous phase. We show that the fluctuations diverge at the critical point so that the mean field approximation ceases to be valid. Actually, the limits N → +∞ and T → T c do not commute. The validity of the mean field approximation requires N( T - T c ) → +∞ so that N must be larger and larger as T approaches T c . We show that the direction of the magnetization changes rapidly close to T c while its amplitude takes a long time to relax. We also indicate that, for systems with long-range interactions, the lifetime of metastable states scales as e N except close to a critical point. The BMF model shares many analogies with other systems of Brownian particles with long-range interactions such as self-gravitating Brownian particles, the Keller-Segel model describing the chemotaxis

  12. Horizontal electric fields from lightning return strokes

    NASA Technical Reports Server (NTRS)

    Thomson, E. M.; Medelius, P. J.; Rubinstein, M.; Uman, M. A.; Johnson, J.

    1988-01-01

    An experiment to measure simultaneously the wideband horizontal and vertical electric fields from lightning return strokes is described. Typical wave shapes of the measured horizontal and vertical fields are presented, and the horizontal fields are characterized. The measured horizontal fields are compared with calculated horizontal fields obtained by applying the wavetilt formula to the vertical fields. The limitations and sources of error in the measurement technique are discussed.

  13. Ohm's law for mean magnetic fields

    SciTech Connect

    Boozer, A.H.

    1984-11-01

    Spatially complicated magnetic fields are frequently treated as the sum of a large, slowly varying, mean field and a small, rapidly varying, field. The primary effect of the small field is to modify the Ohm's law of the mean field. A set of plausible assumptions leads to a form of the mean field Ohm's law which is fundamentally different from the conventional alpha effect of dynamo theory.

  14. Development Factors and Field Dependence-Independence.

    DTIC Science & Technology

    1984-11-01

    The use of field dependence -field independence measures has been suggested for both the selection and classification of naval aviators. If measures...of field dependence -field independence are predictive of pilot proficiency, the utility of the construct for selection and classification could be...moderated by the influence of intraindividual changes in field dependence -field independence (FD-FI) over time. This report reviews (1) particulars of the

  15. Separation of magnetic field lines

    SciTech Connect

    Boozer, Allen H.

    2012-11-15

    The field lines of magnetic fields that depend on three spatial coordinates are shown to have a fundamentally different behavior from those that depend on two coordinates. Unlike two-coordinate cases, a flux tube in a magnetic field that depends on all three spatial coordinates that has a circular cross section at one location along the tube characteristically has a highly distorted cross section at other locations. In an ideal evolution of a magnetic field, the current densities typically increase. Crudely stated, if the current densities increase by a factor {sigma}, the ratio of the long to the short distance across a cross section of a flux tube characteristically increases by e{sup 2{sigma}}, and the ratio of the longer distance to the initial radius increases as e{sup {sigma}}. Electron inertia prevents a plasma from isolating two magnetic field structures on a distance scale shorter than c/{omega}{sub pe}, which is about 10 cm in the solar corona, and reconnection must be triggered if {sigma} becomes sufficiently large. The radius of the sun, R{sub Circled-Dot-Operator }=7 Multiplication-Sign 10{sup 10}cm is about e{sup 23} times larger, so when {sigma} Greater-Than-Or-Equivalent-To 23, two lines separated by c/{omega}{sub pe} at one location can be separated by the full scale of any magnetic structures in the corona at another. The conditions for achieving a large exponentiation, {sigma}, are derived, and the importance of exponentiation is discussed.

  16. Junction-based field emission structure for field emission display

    DOEpatents

    Dinh, Long N.; Balooch, Mehdi; McLean, II, William; Schildbach, Marcus A.

    2002-01-01

    A junction-based field emission display, wherein the junctions are formed by depositing a semiconducting or dielectric, low work function, negative electron affinity (NEA) silicon-based compound film (SBCF) onto a metal or n-type semiconductor substrate. The SBCF can be doped to become a p-type semiconductor. A small forward bias voltage is applied across the junction so that electron transport is from the substrate into the SBCF region. Upon entering into this NEA region, many electrons are released into the vacuum level above the SBCF surface and accelerated toward a positively biased phosphor screen anode, hence lighting up the phosphor screen for display. To turn off, simply switch off the applied potential across the SBCF/substrate. May be used for field emission flat panel displays.

  17. FieldREG II: consciousness field effects: replications and explorations.

    PubMed

    Nelson, R D; Jahn, R G; Dunne, B J; Dobyns, Y H; Bradish, G J

    2007-01-01

    Based on formal analysis of 18 exploratory applications, 12 of which have been reported previously, a testable general hypothesis for FieldREG experiments has been postulated, namely that data taken in environments fostering relatively intense or profound subjective resonance will show larger deviations of the mean relative to chance expectation than those generated in more pragmatic assemblies. The 61 subsequent FieldREG applications reported here comprise 21 hypothesis-based formal replications, along with 40 further explorations designed to learn more about the circumstances that favor anomalous deviations. The results of the formal replications strongly confirm the general hypothesis, yielding a composite probability against chance for the resonant subset of 2.2 x 10(-6) compared to 0.91 for the mundane subset. The exploratory work suggests other venues in which anomalous effects of group consciousness can be expected, and also identifies a number of situations that do not appear to be conducive to such responses.

  18. Photo Field Emission and Field Emission Energy Distributions from Silicon.

    NASA Astrophysics Data System (ADS)

    Herman, Michael H.

    Electron field emission from semiconductors is investigated both theoretically and experimentally. The theoretical predictions of the general Stratton theory are calculated specifically for silicon, in the {100 }, {110}, and {111} directions. A method of simplifying the calculation of the energy distribution for arbitrary semiconductor bands is obtained, utilizing the effective mass approximation. Experimental field emission energy distributions (FEEDs) are reported for both n- and p-type samples of low resistivity. The experimental distributions are characterized by a high intensity single peak, of energy 0.4 eV or more below the Fermi level, with subsidiary peak of lower intensity, rising from just below the Fermi level. The larger peak drops in energy with increasing field. Presented data demonstrates that this peak lowering is not attributable to sample resistance. Observation of the subsidiary peak is linked to either low sample temperature or low doping, implying that the carrier concentration affects its presence. Experimental FEEDs are compared to those expected theoretically. It is concluded that they are not similar. Comparison with photoemission work indicates that the large peak is due to a band of surface acceptor states. The subsidiary peak is tentatively ascribed to conduction band electrons. Finally, a phenomenological model of photo-field emission (PFE) is proposed. Based upon both FEED and PFE experiments, this model assumes that emission occurs primarily from surface states. A second component of the current is due to tunnelling of photogenerated electrons. In addition to photoconductivity, a self-regulating breakdown mechanism is necessary for qualitative agreement with experimental data. One such mechanism, avalanche, is investigated for the dielectric emitter model. Qualitative agreement is obtained with the characteristic non-linear Fowler-Nordheim behavior observed experimentally.

  19. Comments on conformal Killing vector fields and quantum field theory

    SciTech Connect

    Brown, M.R.; Ottewill, A.C.; Siklos, S.T.C.

    1982-10-15

    We give a comprehensive analysis of those vacuums for flat and conformally flat space-times which can be defined by timelike, hypersurface-orthogonal, conformal Killing vector fields. We obtain formulas for the difference in stress-energy density between any two such states and display the correspondence with the renormalized stress tensors. A brief discussion is given of the relevance of these results to quantum-mechanical measurements made by noninertial observers moving through flat space.

  20. Euclidean quantum field theory: Curved spacetimes and gauge fields

    NASA Astrophysics Data System (ADS)

    Ritter, William Gordon

    This thesis presents a new formulation of quantum field theory (QFT) on curved spacetimes, with definite advantages over previous formulations, and an introduction to the millennium prize problem on four-dimensional gauge theory. Our constructions are completely rigorous, making QFT on curved spacetimes into a subfield of mathematics, and we achieve the first analytic control over nonperturbative aspects of interacting theories on curved spacetimes. The success of Euclidean path integrals to capture nonperturbative aspects of QFT has been striking. The Euclidean path integral is the most accurate method of calculating strong-coupling effects in gauge theory (such as glueball masses). Euclidean methods are also useful in the study of black holes, as evidenced by the Hartle-Hawking calculation of black-hole radiance. From a mathematical point of view, on flat spacetimes the Euclidean functional integral provides the most elegant method of constructing examples of interacting relativistic field theories. Yet until now, the incredibly-useful Euclidean path integral had never been given a definitive mathematical treatment on curved backgrounds. It is our aim to rectify this situation. Along the way, we discover that the Dirac operator on an arbitrary Clifford bundle has a resolvent kernel which is the Laplace transform of a positive measure. In studying spacetime symmetries, we discover a new way of constructing unitary representations of noncompact Lie groups. We also define and explore an interesting notion of convergence for Laplacians. The same mathematical framework applies to scalar fields, fermions, and gauge fields. The later chapters are devoted to gauge theory. We present a rigorous, self-contained introduction to the subject, aimed at mathematicians and using the language of modern mathematics, with a view towards nonperturbative renormalization in four dimensions. The latter ideas are unfinished. A completion of the final chapter would imply the construction

  1. Solid rocket motor aft field joint flow field analysis

    NASA Technical Reports Server (NTRS)

    Sabnis, Jayant S.; Gibeling, Edward J.; Mcdonald, Henry

    1987-01-01

    An efficient Navier-Stokes analysis was successfully applied to simulate the complex flow field in the vicinity of a slot in a solid rocket motor with segment joints. The capability of the computer code to resolve the flow near solid surfaces without using a wall function assumption was demonstrated. In view of the complex nature of the flow field in the vicinity of the slot, this approach is considered essential. The results obtained from these calculations provide valuable design information, which would otherwise be extremely difficult to obtain. The results of the axisymmetric calculations indicate the presence of a region of reversed axial flow at the aft-edge of the slot and show the over-pressure in the slot to be only about 10 psi. The results of the asymmetric calculations indicate that a pressure asymmetry more than two diameters downstream of the slot has no noticeable effect on the flow field in the slot. They also indicate that the circumferential pressure differential caused in the slot due to failure of a 15 deg section of the castable inhibitor will be approximately 1 psi.

  2. Carbon nanotube field effect transistors under high magnetic fields

    NASA Astrophysics Data System (ADS)

    Fedorov, Georgy; Smirnov, Dmitry; Tselev, Alexander; Yang, Yanfei; Kalugin, Nikolay

    2006-03-01

    Magnetic field, when applied parallel to the CNT axis, alters the energy gap in the CNT electron spectrum with a period corresponding to one quantum of magnetic flux through the cross-section of the CNT. With available magnetic fields (10^1T by the order of magnitude), gap oscillations can be observed only in multi-wall CNTs with diameters larger than approx 5 nm, where effects of band structure variation are smeared out by defects and by quantum interference effects. As follows from [1], it is possible to separate effects of disorder from those of the band structure modification by studying magnetotransport in small diameter CNTs while controllably changing the position of the Fermi level of the CNT by electrostatic doping, i.e. by applying a gate voltage in the field effect transistor configuration. We have studied several samples of individual CTNs contacted by palladium electrodes placed on an oxidized heavily doped silicon substrate that served as a back-gate. We find that magnetoresistance of a CNT strongly depends on the Fermi level position with respect to the nanotube's charge neutrality point (CNP). Details and the analysis of our experimental data will be presented. [1] S. Roche, R. Saito, Phys. Rev. Lett. 87, 246803 (2001)

  3. Non-Abelian gauge fields

    NASA Astrophysics Data System (ADS)

    Gerbier, Fabrice; Goldman, Nathan; Lewenstein, Maciej; Sengstock, Klaus

    2013-07-01

    Building a universal quantum computer is a central goal of emerging quantum technologies, which has the potential to revolutionize science and technology. Unfortunately, this future does not seem to be very close at hand. However, quantum computers built for a special purpose, i.e. quantum simulators , are currently developed in many leading laboratories. Many schemes for quantum simulation have been proposed and realized using, e.g., ultracold atoms in optical lattices, ultracold trapped ions, atoms in arrays of cavities, atoms/ions in arrays of traps, quantum dots, photonic networks, or superconducting circuits. The progress in experimental implementations is more than spectacular. Particularly interesting are those systems that simulate quantum matter evolving in the presence of gauge fields. In the quantum simulation framework, the generated (synthetic) gauge fields may be Abelian, in which case they are the direct analogues of the vector potentials commonly associated with magnetic fields. In condensed matter physics, strong magnetic fields lead to a plethora of fascinating phenomena, among which the most paradigmatic is perhaps the quantum Hall effect. The standard Hall effect consists in the appearance of a transverse current, when a longitudinal voltage difference is applied to a conducting sample. For quasi-two-dimensional semiconductors at low temperatures placed in very strong magnetic fields, the transverse conductivity, the ratio between the transverse current and the applied voltage, exhibits perfect and robust quantization, independent for instance of the material or of its geometry. Such an integer quantum Hall effect, is now understood as a deep consequence of underlying topological order. Although such a system is an insulator in the bulk, it supports topologically robust edge excitations which carry the Hall current. The robustness of these chiral excitations against backscattering explains the universality of the quantum Hall effect. Another

  4. Variational Methods for Field Theories.

    NASA Astrophysics Data System (ADS)

    Ben-Menahem, Shahar

    The thesis has four parts, dealing with four field theory models: Periodic Quantum Electrodynamics (PQED) in (2 + 1) dimensions, free scalar field theory in (1 + 1) dimensions, the Quantum XY model in (1 + 1) dimensions, and the (1 + 1) dimensional Ising model in a transverse magnetic field. The last three parts deal exclusively with variational methods; the PQED part involves mainly the path-integral approach. The PQED calculation results in a better understanding of the connection between electric confinement through monopole screening, and confinement through tunneling between degenerate vacua. This includes a better quantitative agreement for the string tensions in the two approaches. In the second part, we use free field theory as a loboratory for a new variational blocking-tuncation approximation, in which the high-frequency modes in a block are truncated to wave functions that depend on the slower background modes(Born-Oppenheimer approximation). This "adiabatic truncation" method gives very accurate results for ground -state energy density and correlation functions. Without the adiabatic method, a much larger number of state per block must be kept to get comparable results. Various adiabatic schemes, with one variable kept per site and then two variables per site, are used. For the XY model, several trial wave functions for the ground state are explored, with an emphasis on the periodic Gaussian. A connection is established with the vortex Coulomb gas of the Eclidean path integral approach. The approximations used are taken from the realms of statistical mechanics (mean field approximation, transfer-matrix methods) and of quantum mechanics (iterative blocking schemes). In developing blocking schemes based on continuous variables, problems due to the periodicity of the model were solved. Our results exhibit an order-disorder phase transition. This transition is a rudimentary version of the actual transition known to occur in the XY model, and is

  5. Scalar fields and particle accelerators

    NASA Astrophysics Data System (ADS)

    Sultana, Joseph; Bose, Benjamin

    2015-06-01

    The phenomenon discovered in 2009 by Bañados, Silk and West where particle collisions can achieve arbitrary high center-of-mass (c.m.) energies close to the event horizon of an extreme Kerr black hole, has generated a lot of interest. Although rotation seemed to be an essential requirement, it was later shown that arbitrary high energies can also be achieved for collisions between radially moving particles near the horizon of the electrically charged extreme Reissner-Nordström black hole. Recently Patil and Joshi claimed that instead of spinning up the black hole one can also crank up the c.m. energy of particle collisions by "charging up" a static black hole with a massless scalar field. In this regard they showed that infinite energies can be attained in the vicinity of the naked singularity of the Janis-Newman-Wincour (JNW) spacetime, which contains a massless scalar field that also becomes infinite at the position of the curvature singularity. In this study we show that Patil and Joshi's claim does not apply for other static black hole systems endowed with a massless scalar field. In particular we consider the well-known Bekenstein black hole and the recently discovered Martínez-Troncoso-Zanelli black hole, and show that the expression of the c.m. energy for particle collisions near the event horizons of these black holes is no different than the corresponding case with vanishing scalar field represented by the Schwarzschild solution. Moreover by studying the motion of scalar test charges that interact with the background scalar field in these black hole spacetimes we show that the resulting c.m. energies are even smaller than in the case of free particles. This shows that the infinite energies obtained by Patil and Joshi may not be due to the fact that the black hole contains a massless scalar field, but may be instead related to the geometry of the naked singularity in the JNW spacetime. An analogous case of infinite c.m. energy in the vicinity of a naked

  6. A landscape of field theories

    NASA Astrophysics Data System (ADS)

    Maxfield, Travis; Robbins, Daniel; Sethi, Savdeep

    2016-11-01

    Studying a quantum field theory involves a choice of space-time manifold and a choice of background for any global symmetries of the theory. We argue that many more choices are possible when specifying the background. In the context of branes in string theory, the additional data corresponds to a choice of supergravity tensor fluxes. We propose the existence of a landscape of field theory backgrounds, characterized by the space-time metric, global symmetry background and a choice of tensor fluxes. As evidence for this landscape, we study the supersymmetric six-dimensional (2, 0) theory compactified to two dimensions. Different choices of metric and flux give rise to distinct two-dimensional theories, which can preserve differing amounts of supersymmetry.

  7. Wide Field Instrument Adjutant Scientist

    NASA Astrophysics Data System (ADS)

    Spergel, David

    As Wide Field Instrument Adjutant Scientist, my goal will be to maximize the science capability of the mission in a cost-contained environment. I hope to work with the HQ, project and the FSWG to assure mission success. I plan to play a leadership role in communicating the WFIRST science capabilities to the astronomy community , obtain input from both science teams and the broader community that help derive performance requirements and calibration metrics. I plan to focus on developing the observing program for the deep fields and focus on using them to calibrate instrument performance and capabilities. I plan to organize workshops that will bring together WFIRST team members with astronomers working on LSST, Euclid, JWST, and the ELTs to maximize combined science return. I am also eager to explore the astrometric and stellar seismology capabilities of the instrument with a goal of maximizing science return without affecting science requirements.

  8. Nuclide-migration field experiments

    SciTech Connect

    Erdal, B.R.; Wolfsberg, K.; Johnstone, J.K.; Erickson, K.L.; Friedman, A.M.; Fried, S.; Hines, J.J.

    1981-03-01

    When considering groundwater flow and radionuclide retention in the complex flow systems that can occur in geologic formations, one has a serious problem in determining if laboratory studies are being performed under conditions appropriate to natural systems. This document is the project plan for a program designed to begin to address these problems. The project is being carried out jointly by the Los Alamos National Laboratory, Sandia National Laboratories, and Argonne National Laboratory. The work has three principal objectives: (1) to develop the experimental, instrumental, and safety techniques necessary to conduct controlled, small-scale radionuclide migration field experiments, including those involving actinides; (2) to use these techniques to define radionuclide migration through rock by performing generic, at-depth experiments under closely monitored conditions; and (3) to determine whether available lithologic, geochemical, and hydrologic properties together with existing or developing transport models are sufficient and appropriate to describe real field conditions.

  9. Majorana neutrinos and magnetic fields

    NASA Astrophysics Data System (ADS)

    Schechter, J.; Valle, J. W. F.

    1981-10-01

    It is stressed that if neutrinos are massive they are probably of "Majorana" type. This implies that their magnetic-moment form factor vanishes identically so that the previously discussed phenomenon of spin rotation in a magnetic field would not appear to take place. We point out that Majorana neutrinos can, however, have transition moments. This enables an inhomogeneous magnetic field to rotate both spin and "flavor" of a neutrino. In this case the spin rotation changes particle to antiparticle. The spin-flavor-rotation effect is worked out in detail. We also discuss the parametrization and calculation of the electromagnetic form factors of Majorana neutrinos. Our discussion takes into account the somewhat unusual quantum theory of massive Majorana particles.

  10. Geophysical fields of a megalopolis

    NASA Astrophysics Data System (ADS)

    Spivak, A. A.; Loktev, D. N.; Rybnov, Yu. S.; Soloviev, S. P.; Kharlamov, V. A.

    2016-12-01

    A description of the Center of Geophysical Monitoring for Systematic Investigation of Negative Consequences for the Human Environment and Infrastructure of the City of Moscow Resulting from Natural and Technogenic Factors, which is part of the Institute of Geosphere Dynamics of the Russian Academy of Sciences (IGD RAS), is presented. The results of synchronous observations of the seismic vibrations, electric and acoustic fields, and atmospheric meteoparameters performed at the Center and in the Mikhnevo Geophysical observatory of IGD RAS situated outside of the zone of the Moscow influence are examined. It is shown that the megalopolis influence consists of an increase in the amplitudes of the physical fields, a change in their spectral composition, and the violation of natural periodicities. A technogenic component that has a considerable impact on the natural physical processes in the surface atmosphere is an important factor that characterizes a megalopolis.

  11. Stories from the Arctic field

    NASA Astrophysics Data System (ADS)

    Cain, Michelle

    2016-04-01

    I will discuss my experience co-ordinating a range of communication activities for a multi-university research programme called Methane in the Arctic: Measurements and Modelling. The project included ground- and aircraft-based fieldwork in the European Arctic, as well as computer modelling. Our communication activities included: our own field blog (www.arcticmethane.wordpress.com), which was syndicated to the Scientific American Expeditions blog; writing articles for other blogs with a wider audience than our own; use of twitter; and podcasting our field work. The grand finale to our communications work was a live event at a science festival, in which we took the audience along with us on a recreated research flight, complete with a life-size mock up of a section of our research aircraft. I will discuss my experiences of these forms of communication, and give an evaluation of their successes and failures.

  12. Field errors in superconducting magnets

    SciTech Connect

    Barton, M. Q.

    1982-01-01

    The mission of this workshop is a discussion of the techniques for tracking particles through arbitrary accelerator field configurations to look for dynamical effects that are suggested by various theoretical models but are not amenable to detailed analysis. A major motivation for this type of study is that many of our accelerator projects are based on the use of superconducting magnets which have field imperfections that are larger and of a more complex nature than those of conventional magnets. Questions such as resonances, uncorrectable closed orbit effects, coupling between planes, and diffusion mechanisms all assume new importance. Since, simultaneously, we are trying to do sophisticated beam manipulations such as stacking, high current accelerator, long life storage, and low loss extraction, we clearly need efficient and accurate tracking programs to proceed with confidence.

  13. Deformation quantization of fermi fields

    SciTech Connect

    Galaviz, I. Garcia-Compean, H. Przanowski, M. Turrubiates, F.J.

    2008-04-15

    Deformation quantization for any Grassmann scalar free field is described via the Weyl-Wigner-Moyal formalism. The Stratonovich-Weyl quantizer, the Moyal *-product and the Wigner functional are obtained by extending the formalism proposed recently in [I. Galaviz, H. Garcia-Compean, M. Przanowski, F.J. Turrubiates, Weyl-Wigner-Moyal Formalism for Fermi Classical Systems, arXiv:hep-th/0612245] to the fermionic systems of infinite number of degrees of freedom. In particular, this formalism is applied to quantize the Dirac free field. It is observed that the use of suitable oscillator variables facilitates considerably the procedure. The Stratonovich-Weyl quantizer, the Moyal *-product, the Wigner functional, the normal ordering operator, and finally, the Dirac propagator have been found with the use of these variables.

  14. Gamma radiation field intensity meter

    DOEpatents

    Thacker, L.H.

    1994-08-16

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

  15. Gamma radiation field intensity meter

    DOEpatents

    Thacker, Louis H.

    1995-01-01

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

  16. Gamma radiation field intensity meter

    DOEpatents

    Thacker, Louis H.

    1994-01-01

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

  17. Swarm: ESA's Magnetic Field Mission

    NASA Astrophysics Data System (ADS)

    Drinkwater, M. R.; Haagmans, R.; Floberghagen, R.; Plank, G.; Menard, Y.

    2011-12-01

    Swarm is the fifth Earth Explorer mission in ESA's Living Planet Programme, and is scheduled for launch in 2012. The objective of the Swarm mission is to provide the best-ever survey of the geomagnetic field and its temporal evolution using a constellation of 3 identical satellites. The Mission shall deliver data that allow access to new insights into the Earth system by improved scientific understanding of the Earth's interior and near-Earth electromagnetic environment. After launch and triple satellite release at an initial altitude of about 490 km, a pair of the satellites will fly side-by-side with slowly decaying altitude, while the third satellite will be lifted to 530 km to complete the Swarm constellation. High-precision and high-resolution measurements of the strength, direction and variation of the magnetic field, complemented by precise navigation, accelerometer and electric field measurements, will provide the observations required to separate and model various sources of the geomagnetic field and near-Earth current systems. The mission science goals are to provide a unique view into Earth core dynamics, mantle conductivity, crustal magnetisation, ionospheric and magnetospheric current systems and upper atmosphere dynamics - ranging from understanding the geodynamo to contributing to space weather. The scientific objectives and results from recent scientific studies will be presented. In addition the current status of the project, which is presently approaching the final stage of the development phase, will be addressed. A consortium of European scientific institutes is developing a distributed processing system to produce geophysical (Level 2) data products to the Swarm user community. The setup of Swarm ground segment and the contents of the data products will be addressed. More information on the Swarm mission can be found at the mission web site (see URL below).

  18. Symplectic Clifford Algebraic Field Theory.

    NASA Astrophysics Data System (ADS)

    Dixon, Geoffrey Moore

    We develop a mathematical framework on which is built a theory of fermion, scalar, and gauge vector fields. This field theory is shown to be equivalent to the original Weinberg-Salam model of weak and electromagnetic interactions, but since the new framework is more rigid than that on which the original Weinberg-Salam model was built, a concomitant reduction in the number of assumptions lying outside of the framework has resulted. In particular, parity violation is actually hiding within our framework, and with little difficulty we are able to manifest it. The mathematical framework upon which we build our field theory is arrived at along two separate paths. The first is by the marriage of a Clifford algebra and a Lie superalgebra, the result being called a super Clifford algebra. The second is by providing a new characterization for a Clifford algebra employing its generators and a symmetric array of metric coefficients. Subsequently we generalize this characterization to the case of an antisymmetric array of metric coefficients, and we call the algebra which results a symplectic Clifford algebra. It is upon one of these that we build our field theory, and it is shown that this symplectic Clifford algebra is a particular subalgebra of a super Clifford algebra. The final ingredient is the operation of bracketing which involves treating the elements of our algebra as endomorphisms of a particular inner product space, and employing this space and its inner product to provide us with maps from our algebra to the reals. It is this operation which enables us to manifest the parity violation hiding in our algebra.

  19. Production Hydraulic Packer Field Test

    SciTech Connect

    Schneller, Tricia; Salas, Jose

    2000-06-30

    In October 1999, the Rocky Mountain Oilfield Testing Center and Halliburton Energy Services cooperated on a field test of Halliburton's new Production Hydraulic Packer technology on Well 46-TPX-10 at Naval Petroleum Reserve No. 3 near Casper, WY. Performance of the packer was evaluated in set and unset operations. The packer's ability to seal the annulus between the casing and tubing was hydraulically tested and the results were recorded.

  20. Symmetries in Lagrangian Field Theory

    NASA Astrophysics Data System (ADS)

    Búa, Lucia; Bucataru, Ioan; León, Manuel de; Salgado, Modesto; Vilariño, Silvia

    2015-06-01

    By generalising the cosymplectic setting for time-dependent Lagrangian mechanics, we propose a geometric framework for the Lagrangian formulation of classical field theories with a Lagrangian depending on the independent variables. For that purpose we consider the first-order jet bundles J1π of a fiber bundle π : E → ℝk where ℝk is the space of independent variables. Generalized symmetries of the Lagrangian are introduced and the corresponding Noether theorem is proved.