Science.gov

Sample records for adjacent field lines

  1. 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.}

  2. Rotating superconductor magnet for producing rotating lobed magnetic field lines

    DOEpatents

    Hilal, Sadek K.; Sampson, William B.; Leonard, Edward F.

    1978-01-01

    This invention provides a rotating superconductor magnet for producing a rotating lobed magnetic field, comprising a cryostat; a superconducting magnet in the cryostat having a collar for producing a lobed magnetic field having oppositely directed adjacent field lines; rotatable support means for selectively rotating the superconductor magnet; and means for energizing the superconductor magnet.

  3. The effects of high voltage transmission lines on the health of adjacent resident populations.

    PubMed Central

    Haupt, R C; Nolfi, J R

    1984-01-01

    A community health survey of 438 individuals was taken to detect health problems related to high voltage electrical transmission among an adjacent residential population. Results revealed no significant or consistent relationships between exposure to a high-voltage DC power line and the perceived health problems that were measured. The sample was not, however, large enough to draw statistically significant conclusions regarding possible health effects with a very low incidence. PMID:6689848

  4. Metalliferous sediments adjacent to hydrothermal fields: Distribution and geochemistry

    SciTech Connect

    Cherkashev, G.A. )

    1990-06-01

    The study of metalliferous sediments located at small distances from their sources (10-15 km), such as modern or ancient hydrothermal fields, indicate essential differences in geochemistry compared with metalliferous sediments that occur at greater distances from geothermal fields. Thus, within areas of well-known metalliferous sediment, such as the TAG hydrothermal field, Galapagos Ridge, northern East Pacific Rise (near 13{degree}N), and triple junction zone in the Indian Ocean, are areas of sediment showing the following compositional features: (1) anomalously high concentrations of metals building up sulfide edifices in the central parts of hydrothermal fields (Fe, Cu, Zn, Pb); (2) high noble metal concentrations; (3) rare-earth element patterns characterized by a europium anomaly (Eu/Eu* >1) and with no negative cerium anomaly (Ce/Ce* {>=}1), the latter being a peculiar feature of rare-earth composition of normal metalliferous sediments. The first two features may not always be distinguished based on examination of the bulk rock. Metalliferous sediments of this type are commonly restricted to exposed igneous rocks that supply lithogenic material (volcanic glass, clastic basalt) to the sediments during subsea weathering. Most elemental concentrations (including nonferrous and noble metals) are diluted by this lithogenic material. The diluting effect can be eliminated by recalculation on a detrital-free basis using the concentration of titanium, the element enriched in the detrital component and depleted in hydrothermal sedimentary component. The geochemical anomalies are caused by genetic features, namely that the metals are derived from the oxidation of sulfide minerals either previously building up the hydrothermal body (and transported by bottom currents after oxidation) or incorporated into black smokers (suspension in fluids).

  5. Effect of two nonfumigant nematicides on corn grown in two adjacent fields infested with different nematodes.

    PubMed

    Dickson, D W; Hewlett, T E

    1987-10-01

    The organo-phosphate experimental nematicide, O-ethyl S,S-di-sec-butyl phosphorodithioate (FMC 67825), provided yield increases of corn comparable to carbofuran. Both the emulsifiable concentrate and granular formulations of FMC 67825 were equally effective. The evaluations, duplicated in two adjacent fields, clearly demonstrated the importance of the type of plant pathogenic nematodes infesting the sites. Where Belonolaimus longicaudatus occurred, yield increases ranged from 73% to 80%, whereas in the adjacent field (without B. longicaudatus) yields increases ranged from - 14% to 28%.

  6. 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.

  7. Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches.

    PubMed

    Liu, Yongbo; Liu, Fang; Wang, Chao; Quan, Zhanjun; Li, Junsheng

    2016-09-15

    The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking.

  8. Hedgerow restoration promotes pollinator populations and exports native bees to adjacent fields.

    PubMed

    Morandin, Lora A; Kremen, Claire

    2013-06-01

    In intensive agricultural landscapes, restoration within farms could enhance biodiversity and ecosystem services such as pollination by native pollinators. Although governments and conservation groups are promoting small-scale restoration on working farms, there are few studies that assess whether these practices enhance pollinator communities in restored areas. Further, there is no information on whether floral enhancements will deplete pollinators in adjacent fields by concentrating ambient populations or whether they result in a net increase in abundance in adjacent farm fields. We investigated whether field edges restored with native perennial plants in California's Central Valley agricultural region increased floral abundance and potential bee nesting sites, and native bee and syrphid fly abundance and diversity, in comparison to relatively unmanaged edges. Native bees and syrphid flies collected from flowers were more abundant, species-rich, and diverse at hedgerow sites than in weedy, unmanaged edges. Abundance of bees collected passively in pan traps was negatively correlated with floral abundance, was significantly different from communities captured by net sampling from flowers, and did not distinguish between site types; we therefore focused on the results of net samples and visual observations. Uncommon species of native bees were sevenfold more abundant on hedgerow flowers than on flowers at weedy, unmanaged edges. Of the species on flowers at hedgerows, 40% were exclusive to hedgerow sites, but there were no species exclusively found on flowers at control sites. Hedgerows were especially important for supporting less-common species of native bees in our intensive agricultural landscape. Hedgerows did not concentrate ambient native bee, honey bee, or syphid fly populations, and they acted as net exporters of native bees into adjacent fields. Within-farm habitat restoration such as hedgerow creation may be essential for enhancing native pollinator

  9. Wayward Field Lines Challenge Solar Radiation Models

    NASA Video Gallery

    This video compares the two models for particle distribution over the course of just three hours after an SEP event. The white line represents a magnetic field line, the general path that the SEPs ...

  10. Mortality of passerines adjacent to a North Carolina corn field treated with granular carbofuran.

    USGS Publications Warehouse

    Augspurger, Tom; Smith, Milton R.; Meteyer, Carol U.; Converse, Kathryn A.

    1996-01-01

    Red-winged blackbirds (Agelaius phoeniceus) were collected during an epizootic in southeastern North Carolina (USA). Activity of brain cholinesterase (ChE) was inhibited by 14 to 48% in three of five specimens, and returned to normal levels after incubation. Gastrointestinal tracts were analyzed for 30 anti-ChE agents. Carbofuran, the only compound detected, was present in all specimens at levels from 5.44 to 72.7 μg/g wet weight. Application of granular carbofuran in an adjacent corn field, results of necropsy examinations, and chemical analyses are consistent with a diagnosis of carbofuran poisoning in these specimens.

  11. Field guide to geologic excursions in southwestern Utah and adjacent areas of Arizona and Nevada

    USGS Publications Warehouse

    Lund, William R.; Lund, William R.

    2002-01-01

    This field guide contains road logs for field trips planned in conjunction with the 2002 Rocky Mountain Section meeting of the Geological Society of America held at Southern Utah University in Cedar City, Utah. There are a total of eight field trips, covering various locations and topics in southwestern Utah and adjacent areas of Arizona and Nevada. In addition, the field guide contains a road log for a set of Geological Engineering Field Camp Exercises run annually by the University of Missouri at Rolla in and around Cedar City. Two of the field trips address structural aspects of the geology in southwestern Utah and northwestern Arizona; two trips deal with ground water in the region; and along with the Field Camp Exercises, one trip, to the Grand Staircase, is designed specifically for educators. The remaining trips examine the volcanology and mineral resources of a large area in and around the Tusher Mountains in Utah; marine and brackish water strata in the Grand Staircase-Escalante National Monument; and the Pine Valley Mountains, which are cored by what may be the largest known laccolith in the world. The "Three Corners" area of Utah, Arizona, and Nevada is home to truly world-class geology, and I am confident that all of the 2002 Rocky Mountain Section meeting attendees will find a field trip suited to their interests.

  12. 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.

  13. 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)

  14. ASYMMETRIC DIFFUSION OF MAGNETIC FIELD LINES

    SciTech Connect

    Beresnyak, Andrey

    2013-04-20

    Stochasticity of magnetic field lines is important for particle transport properties. Magnetic field lines separate faster than diffusively in turbulent plasma, which is called superdiffusion. We discovered that this superdiffusion is pronouncedly asymmetric, so that the separation of field lines along the magnetic field direction is different from the separation in the opposite direction. While the symmetry of the flow is broken by the so-called imbalance or cross-helicity, the difference between forward and backward diffusion is not directly due to imbalance, but a non-trivial consequence of both imbalance and non-reversibility of turbulence. The asymmetric diffusion perpendicular to the mean magnetic field entails a variety of new physical phenomena, such as the production of parallel particle streaming in the presence of perpendicular particle gradients. Such streaming and associated instabilities could be significant for particle transport in laboratory, space, and astrophysical plasmas.

  15. Influence of bus stop with left-turn lines between two adjacent signalized intersections

    NASA Astrophysics Data System (ADS)

    Pang, Ming-Bao; Ye, Lan-Hang; Pei, Ya-Nan

    2016-08-01

    Based on the symmetric two-lane Nagel-Schreckenberg (STNS) model, a three-lane cellular automaton model between two intersections containing a bus stop with left-turning buses is established in which model the occurrences of vehicle accidents are taken into account. The characteristics of traffic flows with different ratios of left-turn lines are discussed via the simulation experiments. The results indicate that the left-turn lines have more negative effects on capacity, accident rate as well as delay if the stop is located close to the intersections, where the negative effect in a near-side stop is more severe than that in a far-side one. The range of appropriate position for a bus stop without the bottleneck effect becomes more and more narrow with the increase of the ratio of left-turn bus lines. When the inflow is small, a short signal cycle and a reasonable offset are beneficial. When the inflow reaches or exceeds the capacity, a longer signal cycle is helpful. But if the stop position is inappropriate, the increase of cycle fails in reducing the negative effect of left-turning buses and the effectiveness of offset is weakened. Project supported by the National Natural Science Foundation of China (Grant No. 50478088) and the Natural Science Foundation of Hebei Province, China (Grant No. E2015202266).

  16. Early Growth Response1and Fatty Acid Synthase Expression is Altered in Tumor Adjacent Prostate Tissue and Indicates Field Cancerization

    PubMed Central

    Jones, Anna C.; Trujillo, Kristina A.; Phillips, Genevieve K.; Fleet, Trisha M.; Murton, Jaclyn K.; Severns, Virginia; Shah, Satyan K.; Davis, Michael S.; Smith, Anthony Y.; Griffith, Jeffrey K.; Fischer, Edgar G.; Bisoffi, Marco

    2011-01-01

    BACKGROUND Field cancerization denotes the occurrence of molecular alterations in histologically normal tissues adjacent to tumors. In prostate cancer, identification of field cancerization has several potential clinical applications. However, prostate field cancerization remains ill defined. Our previous work has shown up-regulated mRNA of the transcription factor early growth response 1 (EGR-1) and the lipogenic enzyme fatty acid synthase (FAS) in tissues adjacent to prostate cancer. METHODS Immunofluorescence data were analyzed quantitatively by spectral imaging and linear unmixing to determine the protein expression levels of EGR-1 and FAS in human cancerous, histologically normal adjacent, and disease-free prostate tissues. RESULTS EGR-1 expression was elevated in both structurally intact tumor adjacent (1.6× on average) and in tumor (3.0× on average) tissues compared to disease-free tissues. In addition, the ratio of cytoplasmic versus nuclear EGR-1 expression was elevated in both tumor adjacent and tumor tissues. Similarly, FAS expression was elevated in both tumor adjacent (2.7× on average) and in tumor (2.5× on average) compared to disease-free tissues. CONCLUSIONS EGR-1 and FAS expression is similarly deregulated in tumor and structurally intact adjacent prostate tissues and defines field cancerization. In cases with high suspicion of prostate cancer but negative biopsy, identification of field cancerization could help clinicians target areas for repeat biopsy. Field cancerization at surgical margins on prostatectomy specimen should also be looked at as a predictor of cancer recurrence. EGR-1 and FAS could also serve as molecular targets for chemoprevention. PMID:22127986

  17. 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.

  18. Surface geology of the northern Midway-Sunset Field and adjacent Temblor Range, Kern County, California

    SciTech Connect

    Wylie, A.S. Jr.; Sturm, D.H.; Gardiner, R.L.; Mercer, M.F.

    1996-12-31

    New surface mapping at a 1:12000 scale adjacent to the 2 billion barrel Midway Sunset Field has revealed complex intraformational stratigraphy within the upper Miocene Santa Margarita Formation (Tms). Locally known as the Potter and Spellacy Formations in the subsurface, these sandstone and conglomerate heavy oil reservoirs produce the majority of Midway Sunset daily production of 164,000 barrels of oil via thermal EOR processes. The Tms consists mostly of conglomerate inserted into the Belridge Diatomite (Tmb) interval. The stratigraphically lower intervals of the Tms clearly fill deeply incised valleys or submarine canyons cut into Tmb and locally into the underlying Antelope Shale (Tma). The basal intervals of Tms; are very coarse grained, containing boulders of granitic and metamorphic rock as large as 4 meters that were derived from the Salinian block west of the San Andreas Fault. The upper intervals of Tms are more sheet-like and interbedded containing clasts less than 50 cm in length. The incised valleys have a spacing of about one mile in outcrop, with a gap located in the area of the older Republic Sandstone (Tmr). Paleocurrents from Tms regionally suggest sediment transport to the northeast. The sedimentary structures of Tms suggest deposition in deep-water conditions, probably a slope (bathyal) setting. Shelf environments should have been present to the southwest (now stripped away by erosion) and submarine-fan and basin-floor environments to the northeast.

  19. Surface geology of the northern Midway-Sunset Field and adjacent Temblor Range, Kern County, California

    SciTech Connect

    Wylie, A.S. Jr.; Sturm, D.H.; Gardiner, R.L.; Mercer, M.F. )

    1996-01-01

    New surface mapping at a 1:12000 scale adjacent to the 2 billion barrel Midway Sunset Field has revealed complex intraformational stratigraphy within the upper Miocene Santa Margarita Formation (Tms). Locally known as the Potter and Spellacy Formations in the subsurface, these sandstone and conglomerate heavy oil reservoirs produce the majority of Midway Sunset daily production of 164,000 barrels of oil via thermal EOR processes. The Tms consists mostly of conglomerate inserted into the Belridge Diatomite (Tmb) interval. The stratigraphically lower intervals of the Tms clearly fill deeply incised valleys or submarine canyons cut into Tmb and locally into the underlying Antelope Shale (Tma). The basal intervals of Tms; are very coarse grained, containing boulders of granitic and metamorphic rock as large as 4 meters that were derived from the Salinian block west of the San Andreas Fault. The upper intervals of Tms are more sheet-like and interbedded containing clasts less than 50 cm in length. The incised valleys have a spacing of about one mile in outcrop, with a gap located in the area of the older Republic Sandstone (Tmr). Paleocurrents from Tms regionally suggest sediment transport to the northeast. The sedimentary structures of Tms suggest deposition in deep-water conditions, probably a slope (bathyal) setting. Shelf environments should have been present to the southwest (now stripped away by erosion) and submarine-fan and basin-floor environments to the northeast.

  20. Comparison of some quality properties of soils around land-mined areas and adjacent agricultural fields.

    PubMed

    Ozturkmen, Ali Rıza; Kavdir, Yasemin

    2012-03-01

    When agricultural lands are no longer used for agriculture and allowed to recover its natural vegetation, soil organic carbon can accumulate in the soil. Measurements of soil organic carbon and aggregate stability changes under various forms of land use are needed for the development of sustainable systems. Therefore, comparison of soil samples taken from both agricultural and nearby area close to land-mined fields where no agricultural practices have been done since 1956 can be a good approach to evaluate the effects of tillage and agriculture on soil quality. The objective of this study was to compare tillage, cropping and no tillage effects on some soil-quality parameters. Four different locations along the Turkey-Syria border were selected to determine effects of tillage and cropping on soil quality. Each location was evaluated separately because of different soil type and treatments. Comparisons were made between non-tilled and non-cropped fallow since 1956 and adjacent restricted lands that were tilled about every 2 years but not planted (T) or adjacent lands tilled and planted with wheat and lentil (P). Three samples were taken from the depths of 0-20 and 20-40 cm each site. Soil organic carbon (SOC), pH ,electrical conductivity, water soluble Ca(++), Mg(++), CO₃⁻² and HCO₃⁻, extractable potassium (K(+)) and sodium (Na(+)), soil texture, ammonium (NH₄⁺-N) and nitrate (NO(3)-N), extractable phosphorous and soil aggregate stability were determined. While the SOC contents of continuous tillage without cropping and continuous tillage and cropping were 2.2 and 11.6 g kg(-1), respectively, it was 30 g kg(-1) in non-tilled and non-planted site. Tillage of soil without the input of any plant material resulted in loss of carbon from the soil in all sites. Soil extractable NO(3)-N contents of non-tilled and non-cropped sites were greatest among all treatments. Agricultural practices increased phosphorus and potassium contents in the soil profile. P(2)O(5

  1. Adjacent Habitat Influence on Stink Bug (Hemiptera: Pentatomidae) Densities and the Associated Damage at Field Corn and Soybean Edges

    PubMed Central

    Venugopal, P. Dilip; Coffey, Peter L.; Dively, Galen P.; Lamp, William O.

    2014-01-01

    The local dispersal of polyphagous, mobile insects within agricultural systems impacts pest management. In the mid-Atlantic region of the United States, stink bugs, especially the invasive Halyomorpha halys (Stål 1855), contribute to economic losses across a range of cropping systems. Here, we characterized the density of stink bugs along the field edges of field corn and soybean at different study sites. Specifically, we examined the influence of adjacent managed and natural habitats on the density of stink bugs in corn and soybean fields at different distances along transects from the field edge. We also quantified damage to corn grain, and to soybean pods and seeds, and measured yield in relation to the observed stink bug densities at different distances from field edge. Highest density of stink bugs was limited to the edge of both corn and soybean fields. Fields adjacent to wooded, crop and building habitats harbored higher densities of stink bugs than those adjacent to open habitats. Damage to corn kernels and to soybean pods and seeds increased with stink bug density in plots and was highest at the field edges. Stink bug density was also negatively associated with yield per plant in soybean. The spatial pattern of stink bugs in both corn and soybeans, with significant edge effects, suggests the use of pest management strategies for crop placement in the landscape, as well as spatially targeted pest suppression within fields. PMID:25295593

  2. Denitrification in restored and constructed wetlands adjacent to crop fields on the Mid-Atlantic coastal plain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fertilizer applications on crop fields are a significant source of nitrate (NO3), and groundwater concentrations are frequently 500-1000 µM. We show that groundwater transport of agricultural NO3 results in significant denitrification in adjacent wetlands in the Choptank Basin on the Delmarva Penins...

  3. Quantifying atmospheric stability conditions at a swine facility and an adjacent corn field in Iowa, USA

    NASA Astrophysics Data System (ADS)

    Hernandez-Ramirez, Guillermo; Sauer, Thomas J.; Hatfield, Jerry L.; Prueger, John H.

    2011-10-01

    Atmospheric stability conditions in the atmospheric surface layer control the distance and direction of transport of air contaminants. Near confined animal facilities, transport processes significantly impact air quality as these sites typically act as point sources of dust and odor constituents; however, little information is available on atmospheric stability effects. This study was conducted to assess year-round temporal patterns of atmospheric stability at a swine production facility and an adjacent commercial corn field (CF) in the US Midwest. Two towers of 10 and 20 m heights for continuous micrometeorological measurements were deployed within a CF and between swine buildings (BSB), respectively. Each tower was equipped with an eddy-covariance system at 6.8 m height, infrared thermometers, and six cup anemometers with thermocouples installed at log-distributed heights. Overall results from gradient Richardson number and Monin-Obukhov (z/L) calculations revealed a greater prevalence of unstable conditions for BSB compared with CF. During the 13-month measurement period, unstable cases (z/L ranging from -1 to -0.01) occurred 1.4 times more frequently for BSB than CF (52 vs. 39%, respectively), while stable cases (0.011-0.2) were 1.8 times more frequent for CF than BSB (24 vs. 14%, respectively). These patterns were partly associated with higher surface radiometric temperatures for BSB. Relatively greater diurnal heat capture at BSB (ground and roof surfaces) and a cooling effect in CF through active canopy transpiration during the daytime explain these z/L and radiometric temperature results. Prevalent diurnal atmospheric instability at BSB suggests enhanced ascendant vertical transport of air pollutants perhaps causing greater mixing/dilution with the atmospheric layer and/or their facilitated transport over greater distances when sorbed onto particles. This enhanced understanding of the spatio-temporal patterns of atmospheric stability can be subsequently

  4. Stereotactic radiotherapy for spinal intradural metastases developing within or adjacent to the previous irradiation field--report of three cases.

    PubMed

    Mori, Yoshimasa; Hashizume, Chisa; Shibamoto, Yuta; Kobayashi, Tatsuya; Nakazawa, Hisato; Hagiwara, Masahiro; Tsugawa, Takahiko

    2013-08-01

    Results of stereotactic radiotherapy (SRT) for spinal intradural metastases developing inside or adjacent to the previous external-beam radiation therapy (EBRT) field are shown in 3 cases. One case of spinal intramedullary metastasis and two cases of intradural extramedullary metastases were treated using a Novalis shaped-beam SRT. Case 1 developed an intramedullary metastatic tumor in the C1 spinal medulla inside the previous whole brain EBRT field and another lesion adjacent to the field in the C2 spinal medulla. Case 2 developed intradural extramedullary metastasis around C6-8 inside the previous EBRT field for the primary lung adenocarcinoma. Case 3 developed multiple spinal intradural extramedullary metastatic deposits after surgical resection and following whole brain EBRT for brain metastasis. We delivered 24 to 36 Gy in 5 to 12 fractions. The treated tumors were stable or decreased in size until the patients' death from the primary cancer (10, 22, and 5 months). Neurological symptoms were stable or improved in all 3 patients. Palliative SRT using Novalis is expected to be safe and effective even if the patient develops spinal intradural metastases within or adjacent to the previous irradiation field.

  5. Edge effects of stink bugs in corn, cotton, peanut and soybean fields adjacent to woodland.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers face significant crop losses from stink bug species in the southeastern USA, but the high mobility and polyphagy of the bugs make predictions of their presence in crops difficult. While there is some evidence that they colonize crops from adjacent crops, there are no studies of their colo...

  6. DYNAMICAL FIELD LINE CONNECTIVITY IN MAGNETIC TURBULENCE

    SciTech Connect

    Ruffolo, D.; Matthaeus, W. H.

    2015-06-20

    Point-to-point magnetic connectivity has a stochastic character whenever magnetic fluctuations cause a field line random walk, but this can also change due to dynamical activity. Comparing the instantaneous magnetic connectivity from the same point at two different times, we provide a nonperturbative analytic theory for the ensemble average perpendicular displacement of the magnetic field line, given the power spectrum of magnetic fluctuations. For simplicity, the theory is developed in the context of transverse turbulence, and is numerically evaluated for the noisy reduced MHD model. Our formalism accounts for the dynamical decorrelation of magnetic fluctuations due to wave propagation, local nonlinear distortion, random sweeping, and convection by a bulk wind flow relative to the observer. The diffusion coefficient D{sub X} of the time-differenced displacement becomes twice the usual field line diffusion coefficient D{sub x} at large time displacement t or large distance z along the mean field (corresponding to a pair of uncorrelated random walks), though for a low Kubo number (in the quasilinear regime) it can oscillate at intermediate values of t and z. At high Kubo number the dynamical decorrelation decays mainly from the nonlinear term and D{sub X} tends monotonically toward 2D{sub x} with increasing t and z. The formalism and results presented here are relevant to a variety of astrophysical processes, such as electron transport and heating patterns in coronal loops and the solar transition region, changing magnetic connection to particle sources near the Sun or at a planetary bow shock, and thickening of coronal hole boundaries.

  7. The use of Chironomus riparius larvae to assess effects of pesticides from rice fields in adjacent freshwater ecosystems.

    PubMed

    Faria, Mafalda S; Nogueira, António J A; Soares, Amadeu M V M

    2007-06-01

    A bioassay with Chironomus riparius larvae, using larval development and growth as endpoints, was carried out inside a rice field and in the adjacent wetland channel in Portugal, during pesticide treatments (molinate, endosulfan and propanil) to determine impact caused by pesticide contamination in freshwater ecosystems. The bioassay was also performed under laboratory conditions, to assess whether in situ and laboratory bioassays demonstrated comparable results. Growth was inhibited by concentrations of endosulfan (2.3 and 1.9 microgL(-1) averages) in water from rice field in both the field and laboratory, and by concentrations of endosulfan (0.55 and 0.76 microgL(-1) averages) in water from the wetland channel in the laboratory bioassay, while development was not affected. C. riparius larvae were not affected by molinate and propanil concentrations. The results indicate that endosulfan treatments in rice fields may cause an ecological impairment in adjacent freshwater ecosystems. The results also indicate that laboratory testing can be used to assess in situ toxicity caused by pesticide contamination.

  8. Field Guide to the Geology of Parts of the Appalachian Highlands and Adjacent Interior Plains.

    ERIC Educational Resources Information Center

    McKenzie, Garry D.; Utgard, Russell O.

    This field guide is the basis for a five-day, 1000-mile trip through six states and six geomorphic provinces. The trip and the pre- and post-trip exercises included in the guide constitute a three credit course at The Ohio State University entitled "Field Geology for Science Teachers." The purpose of the trip is to study the regional geology,…

  9. Eph/Ephrin signalling maintains eye field segregation from adjacent neural plate territories during forebrain morphogenesis

    PubMed Central

    Cavodeassi, Florencia; Ivanovitch, Kenzo; Wilson, Stephen W.

    2013-01-01

    During forebrain morphogenesis, there is extensive reorganisation of the cells destined to form the eyes, telencephalon and diencephalon. Little is known about the molecular mechanisms that regulate region-specific behaviours and that maintain the coherence of cell populations undergoing specific morphogenetic processes. In this study, we show that the activity of the Eph/Ephrin signalling pathway maintains segregation between the prospective eyes and adjacent regions of the anterior neural plate during the early stages of forebrain morphogenesis in zebrafish. Several Ephrins and Ephs are expressed in complementary domains in the prospective forebrain and combinatorial abrogation of their activity results in incomplete segregation of the eyes and telencephalon and in defective evagination of the optic vesicles. Conversely, expression of exogenous Ephs or Ephrins in regions of the prospective forebrain where they are not usually expressed changes the adhesion properties of the cells, resulting in segregation to the wrong domain without changing their regional fate. The failure of eye morphogenesis in rx3 mutants is accompanied by a loss of complementary expression of Ephs and Ephrins, suggesting that this pathway is activated downstream of the regional fate specification machinery to establish boundaries between domains undergoing different programmes of morphogenesis. PMID:24026122

  10. Line broadening interference for high-resolution nuclear magnetic resonance spectra under inhomogeneous magnetic fields

    SciTech Connect

    Wei, Zhiliang; Yang, Jian; Lin, Yanqin E-mail: chenz@xmu.edu.cn; Chen, Zhong E-mail: chenz@xmu.edu.cn; Chen, Youhe

    2015-04-07

    Nuclear magnetic resonance spectroscopy serves as an important tool for analyzing chemicals and biological metabolites. However, its performance is subject to the magnetic-field homogeneity. Under inhomogeneous fields, peaks are broadened to overlap each other, introducing difficulties for assignments. Here, we propose a method termed as line broadening interference (LBI) to provide high-resolution information under inhomogeneous magnetic fields by employing certain gradients in the indirect dimension to interfere the magnetic-field inhomogeneity. The conventional spectral-line broadening is thus interfered to be non-diagonal, avoiding the overlapping among adjacent resonances. Furthermore, an inhomogeneity correction algorithm is developed based on pattern recognition to recover the high-resolution information from LBI spectra. Theoretical deductions are performed to offer systematic and detailed analyses on the proposed method. Moreover, experiments are conducted to prove the feasibility of the proposed method for yielding high-resolution spectra in inhomogeneous magnetic fields.

  11. Line broadening interference for high-resolution nuclear magnetic resonance spectra under inhomogeneous magnetic fields.

    PubMed

    Wei, Zhiliang; Yang, Jian; Chen, Youhe; Lin, Yanqin; Chen, Zhong

    2015-04-07

    Nuclear magnetic resonance spectroscopy serves as an important tool for analyzing chemicals and biological metabolites. However, its performance is subject to the magnetic-field homogeneity. Under inhomogeneous fields, peaks are broadened to overlap each other, introducing difficulties for assignments. Here, we propose a method termed as line broadening interference (LBI) to provide high-resolution information under inhomogeneous magnetic fields by employing certain gradients in the indirect dimension to interfere the magnetic-field inhomogeneity. The conventional spectral-line broadening is thus interfered to be non-diagonal, avoiding the overlapping among adjacent resonances. Furthermore, an inhomogeneity correction algorithm is developed based on pattern recognition to recover the high-resolution information from LBI spectra. Theoretical deductions are performed to offer systematic and detailed analyses on the proposed method. Moreover, experiments are conducted to prove the feasibility of the proposed method for yielding high-resolution spectra in inhomogeneous magnetic fields.

  12. Evolution of field line helicity during magnetic reconnection

    SciTech Connect

    Russell, A. J. B. Hornig, G.; Wilmot-Smith, A. L.; Yeates, A. R.

    2015-03-15

    We investigate the evolution of field line helicity for magnetic fields that connect two boundaries without null points, with emphasis on localized finite-B magnetic reconnection. Total (relative) magnetic helicity is already recognized as an important topological constraint on magnetohydrodynamic processes. Field line helicity offers further advantages because it preserves all topological information and can distinguish between different magnetic fields with the same total helicity. Magnetic reconnection changes field connectivity and field line helicity reflects these changes; the goal of this paper is to characterize that evolution. We start by deriving the evolution equation for field line helicity and examining its terms, also obtaining a simplified form for cases where dynamics are localized within the domain. The main result, which we support using kinematic examples, is that during localized reconnection in a complex magnetic field, the evolution of field line helicity is dominated by a work-like term that is evaluated at the field line endpoints, namely, the scalar product of the generalized field line velocity and the vector potential. Furthermore, the flux integral of this term over certain areas is very small compared to the integral of the unsigned quantity, which indicates that changes of field line helicity happen in a well-organized pairwise manner. It follows that reconnection is very efficient at redistributing helicity in complex magnetic fields despite having little effect on the total helicity.

  13. Evolution of field line helicity during magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Russell, A. J. B.; Yeates, A. R.; Hornig, G.; Wilmot-Smith, A. L.

    2015-03-01

    We investigate the evolution of field line helicity for magnetic fields that connect two boundaries without null points, with emphasis on localized finite-B magnetic reconnection. Total (relative) magnetic helicity is already recognized as an important topological constraint on magnetohydrodynamic processes. Field line helicity offers further advantages because it preserves all topological information and can distinguish between different magnetic fields with the same total helicity. Magnetic reconnection changes field connectivity and field line helicity reflects these changes; the goal of this paper is to characterize that evolution. We start by deriving the evolution equation for field line helicity and examining its terms, also obtaining a simplified form for cases where dynamics are localized within the domain. The main result, which we support using kinematic examples, is that during localized reconnection in a complex magnetic field, the evolution of field line helicity is dominated by a work-like term that is evaluated at the field line endpoints, namely, the scalar product of the generalized field line velocity and the vector potential. Furthermore, the flux integral of this term over certain areas is very small compared to the integral of the unsigned quantity, which indicates that changes of field line helicity happen in a well-organized pairwise manner. It follows that reconnection is very efficient at redistributing helicity in complex magnetic fields despite having little effect on the total helicity.

  14. Regions of strongly enhanced perpendicular electric fields adjacent to auroral arcs

    NASA Astrophysics Data System (ADS)

    Opgenoorth, H. J.; Haggstrom, I.; Williams, P. J. S.; Jones, G. O. L.

    1990-08-01

    A joint campaign involving EISCAT, the Cornell University Portable Radar Interferometer (CUPRI), and sounding rockets has observed short-lived elevations of E-region electron temperatures, indicating the presence of strong electric fields. The use of a new pulse-code technique has considerably improved the EISCAT data in regions of low ionospheric electron densities. It has been found that strong and apparently short-lived enhancements of electric fields and associated E-region electron temperatures occur more commonly than long-lived ones. However, earlier EISCAT data with simultaneous optical recordings (and also some CUPRI radar data from the ERRRIS campaign) indicate that many of these events are, in fact, not short-lived, but occur in localized regions and are associated with drifting auroral forms.

  15. The Evolution of Paleostress Fields Adjacent to the Transpressional Alpine Fault in Southwest New Zealand

    NASA Astrophysics Data System (ADS)

    Judge, P.; Klepeis, K.

    2006-05-01

    The Alpine Fault in southwestern New Zealand is part of the transpressional Australia-Pacific plate boundary. Paleostress analyses using fault-slip data from a 400 km2 area of the Darran Mountain, southeast of the Alpine Fault near Milford Sound, reveal both spatial and temporal variations in Tertiary paleostress fields. The northern margin of the Darran Range, within 15 km of the Alpine Fault, records mostly dextral, oblique strike- slip, and thrusts faults. Diorite along this margin also preserves evidence of distributed ductile deformation, recrystallization, and fluid-induced retrogression. The deviatoric stress solution that satisfies the majority of faults from this region has a nearly horizontal west-northwest trending (285° - 295°) axis of maximum compression (σ1). This solution agrees well with published σ1 axes from paleostress data elsewhere along the central (σ1=126° ± 10°) and the northern (σ1=290° - 300°) parts of the Alpine Fault. This σ1 orientation is also congruent with published P-axes determined from earthquakes in southwestern New Zealand. Approximately 25 - 40 km south of the Alpine Fault, normal faults in the central Darran Range record NE-SW directions of subhorizontal extension. These normal faults are consistently cross-cut by widely-spaced (500 - 1000 m) dextral strike-slip and oblique-slip faults. The stress solution that satisfies the majority of the strike-slip faults in this distal region shows a σ1 direction that plunges gently towards the NE (035° - 045°), and a SE-trending (125° - 135°) axis of minimum compression (σ3). We interpret the differences in structure and paleostress states in the Darran Mountains to reflect the superposition of several stress regimes. The stress regime preserved closest to the Alpine Fault is the youngest. Cross-cutting relationships and good agreement between this stress state and P-axes from earthquakes suggest that the west-northwest directions of maximum compression are similar to

  16. Heavy metals accumulation in parts of paddy Oryza sativa L. grown in paddy field adjacent to ultrabasic soil

    NASA Astrophysics Data System (ADS)

    Hadif, Waqeed Mahdi; Rahim, Sahibin Abd; Sahid, Ismail; Bhuiyan, Atiqur Rahman; Ibrahim, Izyanti

    2015-09-01

    The present study was carried out to evaluate the accumulation and translocation of heavy metals from soil around the root zone to various parts of the paddy plant, namely the roots, stems, leaves and rice grains. This study was conducted in 2014 in paddy field adjacent to ultrabasic soil (field 1 and 2) located in Ranau, Sabah and one field (Field 3) taken as control located at the UKM experimental plot in peninsular of Malaysia. The plant species used in the present investigation is Paddy Batu. The heavy metals studied were Chromium (Cr), Iron (Fe) and Nickel (Ni). Heavy metals in soil and plant were extracted by wet digestion method. Heavy metals present in paddy plants and soils extract were measured using the ICP-MS. Heavy metals concentrations in the plant parts in descending order is the root > leaves > stem > rice grain. Lower concentration of all heavy metals in soils and plant parts was shown by the control site (Field 3) in UKM Bangi. Higher concentration of heavy metals occurred in the roots compared to other above ground parts (stem, leaves, and grains) of the paddy plant in all of the paddy field. The bioaccumulation factor (BAF) of heavy metals in all locations were recorded in descending order as Ni > Cr > Fe, the BAF values for all metals in the rice grains were low, whereas the BAF values were recorded high for Ni in all locations. The results also showed that Fe was the most predominant metal ion in the roots, followed by Ni then Cr.

  17. Markers of fibrosis and epithelial to mesenchymal transition demonstrate field cancerization in histologically normal tissue adjacent to breast tumors

    PubMed Central

    Trujillo, Kristina A.; Heaphy, Christopher M.; Mai, Minh; Vargas, Keith M.; Jones, Anna C.; Vo, Phung; Butler, Kimberly S.; Joste, Nancy E.; Bisoffi, Marco; Griffith, Jeffrey K

    2011-01-01

    Previous studies have shown that a field of genetically altered but histologically normal tissue extends 1 cm or more from the margins of human breast tumors. The extent, composition and biological significance of this field are only partially understood, but the molecular alterations in affected cells could provide mechanisms for limitless replicative capacity, genomic instability and a microenvironment that supports tumor initiation and progression. We demonstrate by microarray, qRT-PCR and immunohistochemistry a signature of differential gene expression that discriminates between patient-matched, tumor-adjacent histologically normal breast tissues located 1 cm and 5 cm from the margins of breast adenocarcinomas (TAHN-1 and TAHN-5, respectively). The signature includes genes involved in extracellular matrix remodeling, wound healing, fibrosis and epithelial to mesenchymal transition (EMT). Myofibroblasts, which are mediators of wound healing and fibrosis, and intra-lobular fibroblasts expressing MMP2, SPARC, TGF-β3, which are inducers of EMT, were both prevalent in TAHN-1 tissues, sparse in TAHN-5 tissues, and absent in normal tissues from reduction mammoplasty. Accordingly, EMT markers S100A4 and vimentin were elevated in both luminal and myoepithelial cells, and EMT markers α-smooth muscle actin and SNAIL were elevated in luminal epithelial cells of TAHN-1 tissues. These results identify cellular processes that are differentially activated between TAHN-1 and TAHN-5 breast tissues, implicate myofibroblasts as likely mediators of these processes, provide evidence that EMT is occurring in histologically normal tissues within the affected field and identify candidate biomarkers to investigate whether or how field cancerization contributes to the development of primary or recurrent breast tumors. PMID:21105047

  18. Three-dimensional kinematic reconnection in the presence of field nulls and closed field lines

    NASA Technical Reports Server (NTRS)

    Lau, Yun-Tung; Finn, John M.

    1990-01-01

    The present investigation of three-dimensional reconnection of magnetic fields with nulls and of fields with closed lines gives attention to the geometry of the former, with a view to their gamma-line and Sigma-surface structures. The geometric structures of configurations with a pair of type A and B nulls permit reconnection across the null-null lines; these are the field lines which join the two nulls. Also noted is the case of magnetostatic reconnection, in which the magnetic field is time-independent and the electrostatic potential is constant along field lines.

  19. ON MULTIPLE RECONNECTION X-LINES AND TRIPOLAR PERTURBATIONS OF STRONG GUIDE MAGNETIC FIELDS

    SciTech Connect

    Eriksson, S.; Gosling, J. T.; Lapenta, G.; Newman, D. L.; Goldman, M. V.; Phan, T. D.; Lavraud, B.; Khotyaintsev, Yu. V.; Carr, C. M.; Markidis, S.

    2015-05-20

    We report new multi-spacecraft Cluster observations of tripolar guide magnetic field perturbations at a solar wind reconnection exhaust in the presence of a guide field B{sub M} {sub  }which is almost four times as strong as the reversing field B{sub L}. The novel tripolar field consists of two narrow regions of depressed B{sub M}, with an observed 7%–14% ΔB{sub M} magnitude relative to the external field, which are found adjacent to a wide region of enhanced B{sub M} within the exhaust. A stronger reversing field is associated with each B{sub M} depression. A kinetic reconnection simulation for realistic solar wind conditions and the observed strong guide field reveals that tripolar magnetic fields preferentially form across current sheets in the presence of multiple X-lines as magnetic islands approach one another and merge into fewer and larger islands. The simulated ΔB{sub M}/ΔX{sub N} over the normal width ΔX{sub N} between a B{sub M} minimum and the edge of the external region agree with the normalized values observed by Cluster. We propose that a tripolar guide field perturbation may be used to identify candidate regions containing multiple X-lines and interacting magnetic islands at individual solar wind current sheets with a strong guide field.

  20. Chaotic behavior of magnetic field lines near simplest current systems

    NASA Astrophysics Data System (ADS)

    Veselovsky, I. S.; Lukashenko, A. T.

    2016-12-01

    In the context of studying the problem of simulation of magnetic fields on the Sun, the structure of the field in the vicinity of two circular current loops with different mutual arrangement in space is considered. When the symmetry in the arrangement is sufficient, a system of magnetic surfaces created by the closed field lines arises. With a reduction in symmetry, isolated closed lines may exist. For the case of two identical current loops coupled perpendicularly, it is shown that the subsystems of these lines may be ordered in space in a complex manner. At large distances, a system of loops is equivalent to a dipole with a high degree of accuracy, while an approximate winding of the lines on the deformed toroids, encircling each of the loops, occurs at small distances. At intermediate distances, there are regions of both ordered and chaotic behavior of field lines. Results were obtained with the use of the numerical simulation method.

  1. Field-Line Dispersal and the Death of Lyapunov Exponents

    NASA Astrophysics Data System (ADS)

    Ragot, B. R.

    2008-12-01

    Turbulent magnetic field lines have long been thought to be diverging from each other (or converging towards each other) at exponential rates known as Lyapunov exponents. It is now shown that in a turbulent magnetized plasma, subexponential divergence (convergence) and diffusive twist better characterize the dispersal of magnetic field lines than do the usual Lyapunov exponents or exponentiation rates. Pairs of nearby magnetic field lines diverge (converge) sub-exponentially rather than exponentially, and as soon as they diverge (converge) by a significant amount, they also experience substantial twist or rotation relative to each other. More distant magnetic field lines follow the same dynamics of twist and sub-exponential divergence (convergence), though at a slower rate. It is also found that on a very broad range of separation length scales, the statistics of the field-line separations are log-normal rather than Gaussian. Most importantly, the field-line dispersal can now be evaluated quantitatively and accurately. These results will be presented and some implications for the dispersal and mixing of solar wind magnetic field lines and particles will be discussed.

  2. Present-day Focal Mechanisms and Stress Field of the Sichuan-Yunnan Active Block and Its Adjacent Region

    NASA Astrophysics Data System (ADS)

    zhao, cuiping; luo, jun; zhou, lianqing

    2013-04-01

    Focal mechanism solutions together with the depths of 66 M 3.5 moderate earthquakes occurred in the Sichuan Yunnan active block and its adjacent regions from Aug.1st, 2007 to Sep.15th, 2012was obtained by CAP method. Furthermore, by combining the results with the focal mechanism solutions from Harvard University, we investigated the characteristics of the stress field in the study area. We discussed the spatial distribution of the focal mechanisms and the focal depths, and then analyzed its dynamics. Four conclusions are drawn as follows. (1)Focal mechanism solutions show zoning characteristic. Along the ANH-ZMH-XJ faults(the eastern border of Sichuan-Yunnan block), the earthquakes are mostly left-lateral strike-slip mechanism. Along the HSH fault, the earthquakes are mostly right-lateral strike-slip mechanism. Around the XGLL block and in its interior, there exists remarkable normal fault mechanism with different fault striking and direction of P and T stress axis. Along the arc boundary of Sichuan-Yunnan block with the Sichuan basin, the earthquakes are reverse fault mechanism. (2) The inversed regional stress field shows complicated local feature. On and to the east side of the eastern border of Sichuan-Yunnan block, the stress field is similar with the stress field of the Eastern China block, which is from the relative motion of Philippine plate towards the Urasia plate. Whereas to the west side of the eastern border of Sichuan-Yunnan block, the stress field is much more complicated, indicting the strong influence of local structures to the stress field, especially the NE striking of JPS-YL over-thrusting tectonic structure located in the interior of Sichuan-Yunnan block.(3)The moment center depths of events occurred in the Sichuan-Yunnan active block are within 15km deep, and mostly among 5~15km, suggesting that the brittle seismic layer is among the depth of 5~15km in the upper and middle crust.

  3. Uniform line integral representation of edge-diffracted fields.

    PubMed

    Umul, Yusuf Z

    2008-01-01

    A uniform line integral representation is derived for edge-diffracted fields by using the modified theory of physical optics and uniform asymptotic evaluation methods. The method is applied to the problem of diffraction of plane waves by a semi-infinite edge, which creates tip-diffracted fields with edge-diffracted waves. The uniform diffracted fields are plotted and examined numerically.

  4. Rapid change of field line connectivity and reconnection in stochastic magnetic fields

    SciTech Connect

    Huang, Yi-Min; Bhattacharjee, A.; Boozer, Allen H.

    2014-10-01

    Magnetic fields without a direction of continuous symmetry have the generic feature that neighboring field lines exponentiate away from each other and become stochastic, and hence the ideal constraint of preserving magnetic field line connectivity becomes exponentially sensitive to small deviations from ideal Ohm's law. The idea of breaking field line connectivity by stochasticity as a mechanism for fast reconnection is tested with numerical simulations based on reduced magnetohydrodynamics equations with a strong guide field line-tied to two perfectly conducting end plates. Starting from an ideally stable force-free equilibrium, the system is allowed to undergo resistive relaxation. Two distinct phases are found in the process of resistive relaxation. During the quasi-static phase, rapid change of field line connectivity and strong induced flow are found in regions of high field line exponentiation. However, although the field line connectivity of individual field lines can change rapidly, the overall pattern of field line mapping appears to deform gradually. From this perspective, field line exponentiation appears to cause enhanced diffusion rather than reconnection. In some cases, resistive quasi-static evolution can cause the ideally stable initial equilibrium to cross a stability threshold, leading to formation of intense current filaments and rapid change of field line mapping into a qualitatively different pattern. It is in this onset phase that the change of field line connectivity is more appropriately designated as magnetic reconnection. Our results show that rapid change of field line connectivity appears to be a necessary, but not a sufficient condition for fast reconnection.

  5. Canonical straight field line magnetic flux coordinates for tokamaks

    NASA Astrophysics Data System (ADS)

    Li, Meng; Breizman, Boris N.; Zheng, Linjin

    2016-12-01

    New global straight field line coordinates are introduced for a toroidal plasma configuration. The new coordinate system provides a canonical description of particle guiding center motion while maintaining the straight field line feature. These coordinates are convenient for combining MHD calculations with kinetic modeling of energetic particles. We demonstrate how the new coordinate system can be constructed by transforming the poloidal and toroidal angles. Numerical examples show comparison of the new coordinates with various non-canonical coordinates for the same equilibrium configuration.

  6. Enhancing isolation of antenna arrays by simultaneously blocking and guiding magnetic field lines using magnetic metamaterials

    NASA Astrophysics Data System (ADS)

    Liu, Zhaotang; Wang, Jiafu; Qu, Shaobo; Zhang, Jieqiu; Ma, Hua; Xu, Zhuo; Zhang, Anxue

    2016-10-01

    In this article, we propose to enhance the isolation of antenna arrays by manipulating the near-field magnetic coupling between adjacent antennas using magnetic metamaterials (MMs). Due to the artificially designed negative or large permeability, MMs can concentrate or block the magnetic field lines where they are located, which allows us to tune the near-field magnetic coupling strengths between antennas. MMs can play a two-fold role in enhancing antenna isolation. On one hand, the magnetic fields can be blocked in gaps between adjacent antennas using MMs with negative permeability; on the other hand, the magnetic fields can be pulled towards the borders of the antenna array using MMs with large permeability. As an example, we demonstrated a four-element patch antenna array with split-ring resonators (SRR) integrated in the substrate. The measured results show that the isolation can be enhanced by more than 10 dB with the integration of SRRs, even if the gap between antennas is only about 0.082λ. This work provides an effective alternative to the design of high-isolation antenna arrays.

  7. Magnetic field line lengths inside interplanetary magnetic flux ropes

    NASA Astrophysics Data System (ADS)

    Hu, Qiang; Qiu, Jiong; Krucker, Sam

    2015-07-01

    We report on the detailed and systematic study of field line twist and length distributions within magnetic flux ropes embedded in interplanetary coronal mass ejections (ICMEs). The Grad-Shafranov reconstruction method is utilized together with a constant-twist nonlinear force-free (Gold-Hoyle) flux rope model to reveal the close relation between the field line twist and length in cylindrical flux ropes, based on in situ Wind spacecraft measurements. We show that the field line twist distributions within interplanetary flux ropes are inconsistent with the Lundquist model. In particular, we utilize the unique measurements of magnetic field line lengths within selected ICME events as provided by Kahler et al. () based on energetic electron burst observations at 1 AU and the associated type III radio emissions detected by the Wind spacecraft. These direct measurements are compared with our model calculations to help assess the flux rope interpretation of the embedded magnetic structures. By using the different flux rope models, we show that the in situ direct measurements of field line lengths are consistent with a flux rope structure with spiral field lines of constant and low twist, largely different from that of the Lundquist model, especially for relatively large-scale flux ropes.

  8. Root distribution of Pinus pinaster, P. radiata, Eucalyptus globulus and E. kochii and associated soil chemistry in agricultural land adjacent to tree lines.

    PubMed

    Sudmeyer, R A; Speijers, J; Nicholas, B D

    2004-12-01

    We quantified the extent and distribution of roots of four commonly planted tree species (Eucalyptus globulus Labill., Pinus radiata D. Don, P. pinaster Aiton and E. kochii Maiden & Blakely subsp. plenissima C.A. Gardner) in agricultural land adjacent to tree lines, and examined the effect of soil type and root pruning on root morphology. Root distribution in soil adjacent to tree lines was mapped by a trench profile method at 13 sites on the south coast of Western Australia. Soil samples were collected to determine water content and fertility. The lateral extent of tree roots ranged from 10 m for E. kochii to 44 m for P. pinaster. This equated to between 1.5 and 2.5 times tree height (H) for E. globulus and Pinus spp. to 4H for E. kochii. Root density declined logarithmically with distance from the trees and was greatest for P. pinaster and least for E. globulus (P < 0.001). The rate of decrease in root density with distance from the trees was greatest for the Pinus spp. and least for E. kochii (P < 0.05). Root density was generally greatest in the top 0.5 m of the soil profile and decreased with increasing depth. This decrease was relatively gradual in the deep sands, but abrupt in clay subsoil. Root dry mass in the sandy top soil beyond 0.5H ranged between 1.0 and 55.5 Mg km(treeline) (-1) for 6-year-old E. kochii and 50-year-old P. pinaster, respectively. Soil water content generally increased with distance from the trees (P < 0.001). There was no evidence of reduced soil fertility in the top 1.4 m of the soil profile adjacent to the trees. Two to four years after trees had been root pruned, both the lateral extent and vertical distribution of roots were similar for pruned and unpruned trees. The density of roots < 2 mm in diameter was greater for root-pruned trees than for unpruned trees (P < 0.05). We conclude that the study species can compete with agricultural crops based on the lateral extent of their roots and the occurrence of greatest root density

  9. Breast Field Cancerization: Isolation and Comparison of Telomerase-Expressing Cells in Tumor and Tumor Adjacent, Histologically Normal Breast Tissue

    PubMed Central

    Trujillo, Kristina A.; Hines, William C.; Vargas, Keith M.; Jones, Anna C.; Joste, Nancy E.; Bisoffi, Marco; Griffith, Jeffrey K.

    2011-01-01

    Telomerase stabilizes chromosomes by maintaining telomere length, immortalizes mammalian cells, and is expressed in more than 90% of human tumors. However, the expression of human telomerase reverse transcriptase (hTERT) is not restricted to tumor cells. We have previously shown that a subpopulation of human mammary epithelial cells (HMEC) in tumor-adjacent, histologically normal (TAHN) breast tissues expresses hTERT mRNA at levels comparable with levels in breast tumors. In the current study, we first validated a reporter for measuring levels of hTERT promoter activity in early-passage HMECs and then used this reporter to compare hTERT promoter activity in HMECs derived from tumor and paired TAHN tissues 1, 3, and 5 cm from the tumor (TAHN-1, TAHN-3, and TAHN-5, respectively). Cell sorting, quantitative real-time PCR, and microarray analyses showed that the 10% of HMECs with the highest hTERT promoter activity in both tumor and TAHN-1 tissues contain more than 95% of hTERT mRNA and overexpress many genes involved in cell cycle and mitosis. The percentage of HMECs within this subpopulation showing high hTERT promoter activity was significantly reduced or absent in TAHN-3 and TAHN-5 tissues. We conclude that the field of normal tissue proximal to the breast tumors contains a population of HMECs similar in hTERT expression levels and in gene expression to the HMECs within the tumor mass and that this population is significantly reduced in tissues more distal to the tumor. PMID:21775421

  10. Estimating magnetic fields of homes near transmission lines in the California Power Line Study.

    PubMed

    Vergara, Ximena P; Kavet, Robert; Crespi, Catherine M; Hooper, Chris; Silva, J Michael; Kheifets, Leeka

    2015-07-01

    The California Power Line Study is a case-control study investigating the relation between residences near transmission lines and risk of childhood leukemia. It includes 5788 childhood leukemia cases and 5788 matched primary controls born between 1986 and 2007. We describe the methodology for estimating magnetic fields at study residences as well as for characterizing sources of uncertainty in these estimates. Birth residences of study subjects were geocoded and their distances to transmission lines were ascertained. 302 residences were deemed sufficiently close to transmission lines to have non-zero magnetic fields attributable to the lines. These residences were visited and detailed data, describing the physical configuration and dimensions of the lines contributing to the magnetic field at the residence, were collected. Phasing, loading, and directional load flow data for years of birth and diagnosis for each subject as well as for the day of site visit were obtained from utilities when available; when yearly average load for a particular year was not available, extrapolated values based on expert knowledge and prediction models were obtained. These data were used to estimate the magnetic fields at the center, closest and farthest point of each residence. We found good correlation between calculated fields and spot measurements of fields taken on site during visits. Our modeling strategies yielded similar calculated field estimates, and they were in high agreement with utility extrapolations. Phasing was known for over 90% of the lines. Important sources of uncertainty included a lack of information on the precise location of residences located within apartment buildings or other complexes. Our findings suggest that we were able to achieve high specificity in exposure assessment, which is essential for examining the association between distance to or magnetic fields from power lines and childhood leukemia risk.

  11. Field-Line Resonances in the Current Basis

    NASA Astrophysics Data System (ADS)

    Ostaszewski, Katharina; Glassmeier, Karl-Heinz; Nabert, Christian

    2016-04-01

    The MHD theory of the field-line resonance is of great importance for the understanding of ultra low-frequency waves in the magnetosphere. Most theoretical works concerning field-line resonance use the electric field as the basis set. In an ideal MHD plasma the field-aligned component of the electrical field vanishes because of the frozen-in theorem. However, a field-aligned current flows to maintain quasi-neutrality. This field-aligned current can only be carried by the transverse MHD Alfvèn wave and is therefore a characteristic feature of these types of waves. In this study we investigate the field-line resonance phenomenon using a three dimensional current vector space as the basis set. Using the model of the box magnetosphere of Southwood (1974) we derive an equation for the field-aligned current. This equation provides a simpler and more detailed insight into the coupling process between the fast mode and the Alfvèn mode. Furthermore we investigate the effect of the Hall current on the field-aligned current by including the Hall term in Ohm's law. It is shown that in some situations the Hall current can nullify the filed-aligned current and therefore prevent the resonance.

  12. Low Energy Plasma Measurements of the Van Allen Probes Crossing Open Field Lines

    NASA Astrophysics Data System (ADS)

    Larsen, B.; MacDonald, E.; Skoug, R. M.; Dixon, P.; Henderson, M. G.; Chaston, C. C.; Grande, M.; Funsten, H. O.; Thomsen, M.; Wygant, J. R.; Reeves, G. D.

    2013-12-01

    The Van Allen Probes encountered unusual low-latitude flank-side open field lines during the Nov. 14 2012 geomagnetic storm. Both spacecraft entered the lobes five times over several hours in the main phase of the storm. Four of the ~ five minute events were seen by both probes nearly simultaneously despite being 45 minutes apart in orbit (less than one L shell). The more tailward satellite always saw the boundary crossing first. We present the HOPE low energy plasma observations during these encounters. Adjacent to the lobe intervals, HOPE observed a hot electron plasma sheet leading to significant spacecraft charging. The electron and ion fluxes were significantly diminished during the lobe crossings coincident with a stronger, more highly stretched magnetic field. Significant accelerated field aligned oxygen signatures were measured on both closed and apparently open field lines, along with strong Alfvenic waves. Using the multipoint measurements we will examine the source of this acceleration and its role in inner magnetosphere ion dynamics. This event also represents the chance to constrain and assess magnetic field models and we will examine the topological location of the field lobes relative to the spacecraft for multiple models.

  13. Shallow ground-water quality adjacent to burley tobacco fields in northeastern Tennessee and southwestern Virginia, spring 1997

    USGS Publications Warehouse

    Johnson, G.C.; Connell, J.F.

    2001-01-01

    In 1994, the U.S. Geological Survey began an assessment of the upper Tennessee River Basin as part of the National Water-Quality Assessment (NAWQA) Program. A ground-water land-use study conducted in 1996 focused on areas with burley tobacco production in northeastern Tennessee and southwestern Virginia. Land-use studies are designed to focus on specific land uses and to examine natural and human factors that affect the quality of shallow ground water underlying specific types of land use. Thirty wells were drilled in shallow regolith adjacent to and downgradient of tobacco fields in the Valley and Ridge Physiographic Province of the upper Tennessee River Basin. Ground-water samples were collected between June 4 and July 9, 1997, to coincide with the application of the majority of pesticides and fertilizers used in tobacco production. Ground-water samples were analyzed for nutrients, major ions, 79 pesticides, 7 pesticide degradation products, 86 volatile organic compounds, and dissolved organic carbon. Nutrient concentrations were lower than the levels found in similar NAWQA studies across the United States during 1993-95. Five of 30 upper Tennessee River Basin wells (16.7 percent) had nitrate levels exceeding 10 mg/L while 19 percent of agricultural land-use wells nationally and 7.9 percent in the Southeast had nitrate concentrations exceeding 10 mg/L. Median nutrient concentrations were equal to or less than national median concentrations. All pesticide concentrations in the basin were less than established drinking water standards, and pesticides were detected less frequently than average for other NAWQA study units. Atrazine was detected at 8 of 30 (27 percent) of the wells, and deethylatrazine (an atrazine degradation product) was found in 9 (30 percent) of the wells. Metalaxyl was found in 17 percent of the wells, and prometon, flumetralin, dimethomorph, 2,4,5-T, 2,4-D, dichlorprop, and silvex were detected once each (3 percent). Volatile organic compounds

  14. Length of magnetic field lines in turbulent plasmas.

    PubMed

    Nunez, Manuel

    2002-06-01

    An estimation of the length of any magnetic field line in a two-dimensional periodic magnetohydrodynamic problem is provided. This is done by using some classical function theory results on the analytic extension of the vector potential. The essential parameter, the maximum of this extension, may be analyzed in the case of turbulent plasmas by admitting the Iroshnikov-Kraichnan statistics, establishing in this way a relation between the length of any magnetic field line and the energy dissipation scale. (c) 2002 American Institute of Physics.

  15. Magnetic Field Line Diffusion Footprints on Nonconformal NCSX First Wall

    NASA Astrophysics Data System (ADS)

    Grossman, Arthur

    2005-10-01

    The magnetic fields of the free boundary equilibria of the NCSX compact stellarator are calculated using VMEC and tabulated both inside and outside the LCMS by MFBE/2001 in a form suitable for field line tracing by both GOURDON and Kisslinger field line diffusion. Poincar'{e} plots of equilibrium configurations from 0 to 4/ beta both with and without island healing are made with emphasis placed on the mapping the edge between the LCMS and first wall. Footprints for each configuration on the actual non-conformal wall are found with field line diffusion calculations. Comparison is made with previous conformal wall calculations. It is found that more intersections occur at the close fitting wall at the 60r{ } cross-section than at the tips of the 0r{ } cross-section which has the largest flux expansion of the various cross-sections. Angles of incidence peak in the range 6-12r{ }. Footprints at low diffusion are similar to the high diffusion ones where step size of field line starting points are determined by anomalous thermal diffusivity. The starting surface is selected to be 1 to 2 cm inside the LCMS, and footprints are found to be independent of starting surface selection. An island structure possibly suitable for an island divertor concept is found in the absence of island healing. Other configurations lack islands in the SOL and may require an ergodic divertor concept. The variation of the footprint with beta and island healing is presented.

  16. Measuring Coronal Magnetic Fields with Coronal Emission Line Polarimetry

    NASA Astrophysics Data System (ADS)

    Lin, H.

    2003-12-01

    Magnetic field is the dominating field in the solar corona, responsible for the majestic coronal structures and dynamic events. However, no direct measurements of the coronal magnetic fields are routinely available and we can only infer the coronal magnetic field structures from observed intensity images. Although several methods for the diagnostics of coronal magnetic fields have been demonstrated, measurement of the coronal magnetic fields remains a very challenging observational task. This paper reports on a concerted effort at the Institute for Astronomy (IfA) to establish routine vector coronal magnetic field measurement capabilities using spectropolarimetric observation of the near infrared Fe XIII 1074.7 nm coronal emission line. The IfA effort includes observations of two-dimensional circular polarization maps of the emission line which carry information about the coronal magnetic field strength. High resolution observation of the linear polarization maps which yield the projected direction of the coronal magnetic field in the plane of the sky will also be obtained. The latest results from these experiments will be presented.

  17. Polarized Line Formation in Non-monotonic Velocity Fields

    NASA Astrophysics Data System (ADS)

    Sampoorna, M.; Nagendra, K. N.

    2016-12-01

    For a correct interpretation of the observed spectro-polarimetric data from astrophysical objects such as the Sun, it is necessary to solve the polarized line transfer problems taking into account a realistic temperature structure, the dynamical state of the atmosphere, a realistic scattering mechanism (namely, the partial frequency redistribution—PRD), and the magnetic fields. In a recent paper, we studied the effects of monotonic vertical velocity fields on linearly polarized line profiles formed in isothermal atmospheres with and without magnetic fields. However, in general the velocity fields that prevail in dynamical atmospheres of astrophysical objects are non-monotonic. Stellar atmospheres with shocks, multi-component supernova atmospheres, and various kinds of wave motions in solar and stellar atmospheres are examples of non-monotonic velocity fields. Here we present studies on the effect of non-relativistic non-monotonic vertical velocity fields on the linearly polarized line profiles formed in semi-empirical atmospheres. We consider a two-level atom model and PRD scattering mechanism. We solve the polarized transfer equation in the comoving frame (CMF) of the fluid using a polarized accelerated lambda iteration method that has been appropriately modified for the problem at hand. We present numerical tests to validate the CMF method and also discuss the accuracy and numerical instabilities associated with it.

  18. Environmental data package for ORNL Solid Waste Storage Area Four, the adjacent intermediate-level liquid waste transfer line, and the liquid waste pilot pit area

    SciTech Connect

    Davis, E.C.; Shoun, R.R.

    1986-09-01

    The Oak Ridge National Laboratory Remedial Action Program has determined through its review of past environmental studies that Solid Waste Storage Area Four (SWSA-4) continually releases radioactivity to White Oak Creek and therefore requires application of the site stabilization and remedial actions outlined under the 3004u provisions of the Resource Conservation and Recovery Act. Under these provisions, a Remedial Investigation/Feasibility Study (RI/FS) forms the basis for determining the extent of actions. This report assembles available historical and environmental data relative to the SWSA-4 waste area grouping (WAG), which includes the 9.3-ha SWSA-4 site, the adjacent abandoned intermediate-level liquid waste transfer line, and the experimental pilot pit area. The rationale for grouping these three waste management units into the SWSA-4 WAG is the fact that they each lie in the same hydrologic unit and share a common tributary to White Oak Creek. The results of this compilation demonstrate that although a considerable number of studies have been carried out in SWSA-4, needs such as installation of water quality wells and continued monitoring and reporting of hydrologic data still exist. These needs will become even more critical as the RI/FS process proceeds and remedial measures for the site are considered. Fewer studies have been carried out to characterize the extent of contamination at the waste transfer line and the pilot pit area. Alternatives for characterizing and stabilizing these two minor components of the SWSA-4 WAG are presented; however, extensive remedial actions do not appear to be warranted.

  19. Profiled spectral lines generated in the field of Kerr superspinars

    SciTech Connect

    Schee, Jan; Stuchlík, Zdenek E-mail: zdenek.stuchlik@fpf.slu.cz

    2013-04-01

    String Theory suggests existence of primordial Kerr superspinars, extremely compact objects with external spacetime described by the Kerr naked singularity geometry. The primordial Kerr superspinars have to be converted to a near-extreme black hole due to accretion, but they could survive to the era of highly redshifted quasars. We study the shape of the profiled spectral lines generated by radiating rings or the innermost parts of Keplerian discs orbiting the Kerr superspinars. Influence of the superspinar surface location on the profiled lines is also considered. We demonstrate strong difference of the character of the profiled lines generated by radiating rings for all values of the superspinar spin and all values of the inclination angles of the observer when compared to those generated in the field of Kerr black holes. For small and mediate inclination angles there are large quantitative differences in the extension and position of the lines. For large inclination angles even strong qualitative difference appears as the profiled lines have a clear doubled character. The smaller, redshifted region of the profiled line is related to the photons reaching the regions near the superspinar surface. Strong differences are obtained also for profiled lines generated by the innermost parts of Keplerian discs especially in the shape of the line. The influence of the superspinar surface location is reflected in the intermediate parts of the the profiled lines. The line profiles can give a clear signature of the presence of a Kerr superspinar and in principle enable estimates of its surface location since the signatures of the superspinar surface location are of different character as those corresponding to the presence of the black hole horizon.

  20. Comparison of GHG fluxes from conventional and energy crop production from adjacent fields in the UK, using novel technologies

    NASA Astrophysics Data System (ADS)

    Keane, James Benjamin; Ineson, Phil; Toet, Sylvia; Stockdale, James; Vallack, Harry; Blei, Emanuel; Bentley, Mark; Howarth, Steve

    2016-04-01

    With combustion of fossil fuels driving anthropogenic climate change, allied to a diminishing global reserve of these resources it is vital for alternative sources of energy production to be investigated. One alternative is biomass; ethanol fermented from corn (Zea mays) or sugar cane (Saccharum spp.) has long been used as a petroleum substitute, and oilseed rape (OSR, Brassica napus) is the principal feedstock for biodiesel production in Germany, the third biggest producer of this fuel globally. Diverting food crops into energy production would seem counter-productive, given there exists genuine concern regarding our ability to meet future global food demand, thus attention has turned to utilising lignocellulosic material: woody tissue and non-food crop by-products such as corn stover. For this reason species such as the perennial grass Miscanthus (Miscanthus x giganteus) are being cultivated for energy production, and these are referred to as second generation energy crops. They are attractive since they do not deplete food supplies, have high yields, require less fertiliser input than annual arable crops, and can be grown on marginal agricultural land. To assess the effectiveness of a crop for bioenergy production, it is vital that accurate quantification of greenhouse gas (GHG) fluxes is obtained for their cultivation in the field. We will present data from a series of studies investigating the GHG fluxes from the energy crops OSR and Miscanthus under various nutrient additions in a comparison with conventional arable cropping at the same site in the United Kingdom (UK). A combination of methods were employed to measure fluxes of CO2, CH4 and N2O from both soil and vegetation, at various temporal and spatial scales. Conventional manual chambers were deployed on a monthly regime to quantify soil GHG fluxes, and were supplemented with automated soil flux chambers measuring soil respiration at an hourly frequency. Additionally, two novel automated chamber systems

  1. Parallel field line and stream line tracing algorithms for space physics applications

    NASA Astrophysics Data System (ADS)

    Toth, G.; de Zeeuw, D.; Monostori, G.

    2004-05-01

    Field line and stream line tracing is required in various space physics applications, such as the coupling of the global magnetosphere and inner magnetosphere models, the coupling of the solar energetic particle and heliosphere models, or the modeling of comets, where the multispecies chemical equations are solved along stream lines of a steady state solution obtained with single fluid MHD model. Tracing a vector field is an inherently serial process, which is difficult to parallelize. This is especially true when the data corresponding to the vector field is distributed over a large number of processors. We designed algorithms for the various applications, which scale well to a large number of processors. In the first algorithm the computational domain is divided into blocks. Each block is on a single processor. The algorithm folows the vector field inside the blocks, and calculates a mapping of the block surfaces. The blocks communicate the values at the coinciding surfaces, and the results are interpolated. Finally all block surfaces are defined and values inside the blocks are obtained. In the second algorithm all processors start integrating along the vector field inside the accessible volume. When the field line leaves the local subdomain, the position and other information is stored in a buffer. Periodically the processors exchange the buffers, and continue integration of the field lines until they reach a boundary. At that point the results are sent back to the originating processor. Efficiency is achieved by a careful phasing of computation and communication. In the third algorithm the results of a steady state simulation are stored on a hard drive. The vector field is contained in blocks. All processors read in all the grid and vector field data and the stream lines are integrated in parallel. If a stream line enters a block, which has already been integrated, the results can be interpolated. By a clever ordering of the blocks the execution speed can be

  2. Mapping magnetic field lines between the Sun and Earth

    NASA Astrophysics Data System (ADS)

    Li, B.; Cairns, Iver H.; Gosling, J. T.; Steward, G.; Francis, M.; Neudegg, D.; Schulte in den Bäumen, H.; Player, P. R.; Milne, A. R.

    2016-02-01

    Magnetic field topologies between the Sun and Earth are important for the connectivity to Earth of solar suprathermal particles, e.g., solar energetic particles and beam electrons in type III solar radio bursts. An approach is developed for mapping large-scale magnetic field lines near the solar equatorial plane, using near-Earth observations and a solar wind model with nonzero azimuthal magnetic field at the source surface. Unlike Parker's spiral model, which restricts the in-ecliptic angle ΦB in the Geocentric Solar Ecliptic coordinates to (90°-180°, 270°-360°) and so is unable to predict field configurations for the other ΦB values frequently observed in the solar wind, our approach can account for all the observed ΦB values. A set of predicted maps shows that near both minimal and maximal solar activity the field lines are typically open and that loops with both ends either connected to or disconnected from the Sun are relatively rare. The open field lines, nonetheless, often do not closely follow the Parker spiral, being less or more tightly wound, or strongly azimuthally or radially oriented, or inverted. The time-varying classes, e.g., bidirectional electrons, of suprathermal electron pitch angle distributions (PADs) at 1 AU are predicted from the mapped field line configurations and compared with Wind observations for two solar rotations, one each near solar minimum and solar maximum. PAD predictions by our approach agree quantitatively (≈90%) with the PAD observations and outperform (by ≈20%) PAD predictions using Parker's model.

  3. Visualizing Vector Fields Using Line Integral Convolution and Dye Advection

    NASA Technical Reports Server (NTRS)

    Shen, Han-Wei; Johnson, Christopher R.; Ma, Kwan-Liu

    1996-01-01

    We present local and global techniques to visualize three-dimensional vector field data. Using the Line Integral Convolution (LIC) method to image the global vector field, our new algorithm allows the user to introduce colored 'dye' into the vector field to highlight local flow features. A fast algorithm is proposed that quickly recomputes the dyed LIC images. In addition, we introduce volume rendering methods that can map the LIC texture on any contour surface and/or translucent region defined by additional scalar quantities, and can follow the advection of colored dye throughout the volume.

  4. Limiting electric fields of HVDC overhead power lines.

    PubMed

    Leitgeb, N

    2014-05-01

    As a consequence of the increased use of renewable energy and the now long distances between energy generation and consumption, in Europe, electric power transfer by high-voltage (HV) direct current (DC) overhead power lines gains increasing importance. Thousands of kilometers of them are going to be built within the next years. However, existing guidelines and regulations do not yet contain recommendations to limit static electric fields, which are one of the most important criteria for HVDC overhead power lines in terms of tower design, span width and ground clearance. Based on theoretical and experimental data, in this article, static electric fields associated with adverse health effects are analysed and various criteria are derived for limiting static electric field strengths.

  5. On the generation of magnetic field enhanced microwave plasma line

    NASA Astrophysics Data System (ADS)

    Chen, Longwei; Zhao, Ying; Wu, Kenan; Wang, Qi; Meng, Yuedong; Ren, Zhaoxing

    2016-12-01

    Microwave linear plasmas sustained by surface waves have attracted much attention due to the potential abilities to generate large-scale and uniform non-equilibrium plasmas. An external magnetic field was generally applied to enhance and stabilize plasma sources because the magnetic field decreased the electron losses on the wall. The effects of magnetic field on the generation and propagation mechanisms of the microwave plasma were tentatively investigated based on a 2-D numerical model combining a coupled system of Maxwell's equations and continuity equations. The mobility of electrons and effective electric conductivity of the plasma were considered as a full tensor in the presence of magnetic field. Numerical results indicate that both cases of magnetic field in the axial-direction and radial-direction benefit the generation of a high-density plasma; the former one allows the microwave to propagate longer in the axis direction compared to the latter one. The time-averaged power flow density and the amplitude of the electric field on the inner rod of coaxial waveguide attenuate with the propagation of the microwave for both cases of with and without external magnetic field. The attenuation becomes smaller in the presence of appropriately higher axial-direction magnetic field, which allows more microwave energies to transmit along the axial direction. Meanwhile, the anisotropic properties of the plasma, like electron mobility, in the presence of the magnetic field confine more charged particles in the direction of the magnetic field line.

  6. Observability of atomic line features in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Wunner, G.; Ruder, H.; Herold, H.; Truemper, J.

    1981-01-01

    The physical properties of atoms in superstrong magnetic fields, characteristic of neutron stars, and the possibility of detecting magnetically strongly shifted atomic lines in the spectra of magnetized X-ray pulsars are discussed. It is suggested that it is recommendable to look for magnetically strongly shifted Fe 26 Lyman lines in rotating neutron stars of not too high luminosity using spectrometers working in the energy range 10 - 20 keV, with sensitivities to minus 4 power photons per sq cm and second, and resolution E/delta E approx. 10-100.

  7. Field line twist and field-aligned currents in an axially symmetric equilibrium magnetosphere. [of Uranus

    NASA Technical Reports Server (NTRS)

    Voigt, Gerd-Hannes

    1986-01-01

    Field-aligned Birkeland currents and the angle of the magnetic line twist were calculated for an axially symmetric pole-on magnetosphere (assumed to be in MHD equilibrium). The angle of the field line twist was shown to have a strong radial dependence on the axisymmetric magnetotail as well as on the ionospheric conductivity and the amount of thermal plasma contained in closed magnetotail flux tubes. The field line twist results from the planetary rotation, which leads to the development of a toroidal magnetic B-sub-phi component and to differentially rotating magnetic field lines. It was shown that the time development of the toroidal magnetic B-sub-phi component and the rotation frequency are related through an induction equation.

  8. Fast wave power flow along SOL field lines in NSTX

    NASA Astrophysics Data System (ADS)

    Perkins, R. J.; Bell, R. E.; Diallo, A.; Gerhardt, S.; Hosea, J. C.; Jaworski, M. A.; Leblanc, B. P.; Kramer, G. J.; Phillips, C. K.; Roquemore, L.; Taylor, G.; Wilson, J. R.; Ahn, J.-W.; Gray, T. K.; Green, D. L.; McLean, A.; Maingi, R.; Ryan, P. M.; Jaeger, E. F.; Sabbagh, S.

    2012-10-01

    On NSTX, a major loss of high-harmonic fast wave (HHFW) power can occur along open field lines passing in front of the antenna over the width of the scrape-off layer (SOL). Up to 60% of the RF power can be lost and at least partially deposited in bright spirals on the divertor floor and ceiling [1,2]. The flow of HHFW power from the antenna region to the divertor is mostly aligned along the SOL magnetic field [3], which explains the pattern of heat deposition as measured with infrared (IR) cameras. By tracing field lines from the divertor back to the midplane, the IR data can be used to estimate the profile of HHFW power coupled to SOL field lines. We hypothesize that surface waves are being excited in the SOL, and these results should benchmark advanced simulations of the RF power deposition in the SOL (e.g., [4]). Minimizing this loss is critical optimal high-power long-pulse ICRF heating on ITER while guarding against excessive divertor erosion.[4pt] [1] J.C. Hosea et al., AIP Conf Proceedings 1187 (2009) 105. [0pt] [2] G. Taylor et al., Phys. Plasmas 17 (2010) 056114. [0pt] [3] R.J. Perkins et al., to appear in Phys. Rev. Lett. [0pt] [4] D.L. Green et al., Phys. Rev. Lett. 107 (2011) 145001.

  9. Prostate Field Cancerization: Deregulated Expression of Macrophage Inhibitory Cytokine 1 (MIC-1) and Platelet Derived Growth Factor A (PDGF-A) in Tumor Adjacent Tissue

    PubMed Central

    Jones, Anna C.; Shoshan, Dor S.; Fischer, Edgar G.; Trujillo, Kristina A.; Bisoffi, Marco

    2015-01-01

    Prostate field cancerization denotes molecular alterations in histologically normal tissues adjacent to tumors. Such alterations include deregulated protein expression, as we have previously shown for the key transcription factor early growth response 1 (EGR-1) and the lipogenic enzyme fatty acid synthase (FAS). Here we add the two secreted factors macrophage inhibitory cytokine 1 (MIC-1) and platelet derived growth factor A (PDGF-A) to the growing list of protein markers of prostate field cancerization. Expression of MIC-1 and PDGF-A was measured quantitatively by immunofluorescence and comprehensively analyzed using two methods of signal capture and several groupings of data generated in human cancerous (n = 25), histologically normal adjacent (n = 22), and disease-free (n = 6) prostate tissues. A total of 208 digitized images were analyzed. MIC-1 and PDGF-A expression in tumor tissues were elevated 7.1x to 23.4x and 1.7x to 3.7x compared to disease-free tissues, respectively (p<0.0001 to p = 0.08 and p<0.01 to p = 0.23, respectively). In support of field cancerization, MIC-1 and PDGF-A expression in adjacent tissues were elevated 7.4x to 38.4x and 1.4x to 2.7x, respectively (p<0.0001 to p<0.05 and p<0.05 to p = 0.51, respectively). Also, MIC-1 and PDGF-A expression were similar in tumor and adjacent tissues (0.3x to 1.0x; p<0.001 to p = 0.98 for MIC-1; 0.9x to 2.6x; p<0.01 to p = 1.00 for PDGF-A). All analyses indicated a high level of inter- and intra-tissue heterogeneity across all types of tissues (mean coefficient of variation of 86.0%). Our data shows that MIC-1 and PDGF-A expression is elevated in both prostate tumors and structurally intact adjacent tissues when compared to disease-free specimens, defining field cancerization. These secreted factors could promote tumorigenesis in histologically normal tissues and lead to tumor multifocality. Among several clinical applications, they could also be exploited as indicators of disease in false negative

  10. Prostate field cancerization: deregulated expression of macrophage inhibitory cytokine 1 (MIC-1) and platelet derived growth factor A (PDGF-A) in tumor adjacent tissue.

    PubMed

    Jones, Anna C; Antillon, Kresta S; Jenkins, Shannon M; Janos, Sara N; Overton, Heidi N; Shoshan, Dor S; Fischer, Edgar G; Trujillo, Kristina A; Bisoffi, Marco

    2015-01-01

    Prostate field cancerization denotes molecular alterations in histologically normal tissues adjacent to tumors. Such alterations include deregulated protein expression, as we have previously shown for the key transcription factor early growth response 1 (EGR-1) and the lipogenic enzyme fatty acid synthase (FAS). Here we add the two secreted factors macrophage inhibitory cytokine 1 (MIC-1) and platelet derived growth factor A (PDGF-A) to the growing list of protein markers of prostate field cancerization. Expression of MIC-1 and PDGF-A was measured quantitatively by immunofluorescence and comprehensively analyzed using two methods of signal capture and several groupings of data generated in human cancerous (n = 25), histologically normal adjacent (n = 22), and disease-free (n = 6) prostate tissues. A total of 208 digitized images were analyzed. MIC-1 and PDGF-A expression in tumor tissues were elevated 7.1x to 23.4x and 1.7x to 3.7x compared to disease-free tissues, respectively (p<0.0001 to p = 0.08 and p<0.01 to p = 0.23, respectively). In support of field cancerization, MIC-1 and PDGF-A expression in adjacent tissues were elevated 7.4x to 38.4x and 1.4x to 2.7x, respectively (p<0.0001 to p<0.05 and p<0.05 to p = 0.51, respectively). Also, MIC-1 and PDGF-A expression were similar in tumor and adjacent tissues (0.3x to 1.0x; p<0.001 to p = 0.98 for MIC-1; 0.9x to 2.6x; p<0.01 to p = 1.00 for PDGF-A). All analyses indicated a high level of inter- and intra-tissue heterogeneity across all types of tissues (mean coefficient of variation of 86.0%). Our data shows that MIC-1 and PDGF-A expression is elevated in both prostate tumors and structurally intact adjacent tissues when compared to disease-free specimens, defining field cancerization. These secreted factors could promote tumorigenesis in histologically normal tissues and lead to tumor multifocality. Among several clinical applications, they could also be exploited as indicators of disease in false negative

  11. Diffusion of Magnetic Field Lines in Astrophysically-Relevant Stochastic Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Barghouty, A. F.; Jokipii, J. R.

    1996-05-01

    We present a simple analytic model in which the KS-entropy for the exponential divergence of two neighboring field lines of an astrophysically-relevant stochastic magnetic field can be estimated. We treat the problem as a diffusive (random-walk) process describable by a Fokker-Planck equation and approximated by the standard nonlinear map. For Kolmogorov-like turbulence, we find that the field lines exhibit a non-Gaussian (or anomalous) diffusion for weak to moderate turbulence strength, consistent with a recent MHD numerical calculation(Zimbardo, G., et al. (1995), Phys. Plasmas 2), 2653., but in sharp contrast with simple quasilinear predictions. For moderate to strong turbulence, however, both our model and the numerical MHD study support such predictions in that the field lines appear to follow a Gaussian-like diffusion. Brief description of the model as well as implications to transport mechanisms of charged particles across turbulent magnetic fields will be presented.

  12. Electromagnetic plasma wave emissions from the auroral field lines

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.

    1977-01-01

    The most important types of auroral radio emissions are reviewed, both from a historical perspective as well as considering the latest results. Particular emphasis is placed on four types of electromagnetic emissions which are directly associated with the plasma on the auroral field lines. These emissions are (1) auroral hiss, (2) saucers, (3) ELF noise bands, and (4) auroral kilometric radiation. Ray tracing and radio direction finding measurements indicate that both the auroral hiss and auroral kilometric radiation are generated along the auroral field lines relatively close to the earth, at radial distances from about 2.5 to 5 R sub e. For the auroral hiss the favored mechanism appears to be amplified Cerenkov radiation. For the auroral kilometric radiation several mechanisms have been proposed, usually involving the intermediate generation of electrostatic waves by the precipitating electrons.

  13. Single shot line-field optical coherence elastography

    NASA Astrophysics Data System (ADS)

    Liu, Chih-Hao; Schill, Alexander; Singh, Manmohan; Wu, Chen; Li, Jiasong; Han, Zhaolong; Raghunathan, Raksha; Kazemi, Tina; Nair, Achuth; Hsu, Thomas; Larin, Kirill V.

    2016-03-01

    Elastic wave imaging optical coherence elastography (EWI-OCE) is an emerging technique that can quantify local biomechanical properties of tissues. However, long acquisition times make this technique unfeasible for clinical use. Here, we demonstrate a noncontact single shot line-field OCE technique using a line-field interferometer and an air-pulse delivery system. The spatial-temporal elastic wave propagation profile was acquired in a single shot and used to quantify the elastic wave group velocity in tissue. Results on tissue-mimicking phantoms and chicken breast muscle agreed well with mechanical compression testing, demonstrating that the presented method can effectively reduce the OCE acquisition time to a few milliseconds in biological application.

  14. Field quality measurements of a 2-Tesla transmission line magnet

    SciTech Connect

    Velev, G.V.; Foster, W.; Kashikhin, V.; Mazur, P.; Oleck, A.; Piekarz, H.; Schlabach, P.; Sylvester, C.; Wake, M.; /KEK, Tsukuba

    2005-09-01

    A prototype 2-Tesla superconducting transmission line magnet for future hadron colliders was designed, built and tested at Fermilab. The 1.5 m long, combined-function gradient-dipole magnet has a vertical pole aperture of 20 mm. To measure the magnetic field quality in such a small magnet aperture, a specialized rotating coil of 15.2 mm diameter, 0.69 m long was fabricated. Using this probe, a program of magnetic field quality measurements was successfully performed. Results of the measurements are presented and discussed.

  15. Gas insulated transmission line with insulators having field controlling recesses

    DOEpatents

    Cookson, Alan H.; Pederson, Bjorn O.

    1984-01-01

    A gas insulated transmission line having a novel insulator for supporting an inner conductor concentrically within an outer sheath. The insulator has a recess contiguous with the periphery of one of the outer and inner conductors. The recess is disposed to a depth equal to an optimum gap for the dielectric insulating fluid used for the high voltage insulation or alternately disposed to a large depth so as to reduce the field at the critical conductor/insulator interface.

  16. A molecular line scan in the Hubble deep field north

    SciTech Connect

    Decarli, R.; Walter, F.; Colombo, D.; Da Cunha, E.; Rix, H.-W.; Carilli, C.; Riechers, D.; Cox, P.; Neri, R.; Downes, D.; Aravena, M.; Bell, E.; Bertoldi, F.; Daddi, E.; Sargent, M.; Ellis, R.; Lentati, L.; Maiolino, R.; Menten, K. M.; and others

    2014-02-20

    We present a molecular line scan in the Hubble Deep Field North (HDF-N) that covers the entire 3 mm window (79-115 GHz) using the IRAM Plateau de Bure Interferometer. Our CO redshift coverage spans z ≲ 0.45, 1 ≲ z ≲ 1.9 and all z ≳ 2. We reach a CO detection limit that is deep enough to detect essentially all z > 1 CO lines reported in the literature so far. We have developed and applied different line-searching algorithms, resulting in the discovery of 17 line candidates. We estimate that the rate of false positive line detections is ∼2/17. We identify optical/NIR counterparts from the deep ancillary database of the HDF-N for seven of these candidates and investigate their available spectral energy distributions. Two secure CO detections in our scan are identified with star-forming galaxies at z = 1.784 and at z = 2.047. These galaxies have colors consistent with the 'BzK' color selection and they show relatively bright CO emission compared with galaxies of similar dust continuum luminosity. We also detect two spectral lines in the submillimeter galaxy HDF 850.1 at z = 5.183. We consider an additional nine line candidates as high quality. Our observations also provide a deep 3 mm continuum map (1σ noise level = 8.6 μJy beam{sup –1}). Via a stacking approach, we find that optical/MIR bright galaxies contribute only to <50% of the star formation rate density at 1 < z < 3, unless high dust temperatures are invoked. The present study represents a first, fundamental step toward an unbiased census of molecular gas in 'normal' galaxies at high-z, a crucial goal of extragalactic astronomy in the ALMA era.

  17. Constructing the Coronal Magnetic Field: by Correlating Parameterized Magnetic Field Lines with Observed Coronal Plasma Structures

    NASA Technical Reports Server (NTRS)

    Gary, G. A.

    1998-01-01

    The reconstruction of the coronal magnetic field is carried out using a perturbation procedure. A set of magnetic field lines generated from magnetogram data is parameterized and then deformed by varying the parameterized values. The coronal fluxtubes associated with this field are adjusted until the correlation between the field lines and the observed coronal loops is maximized. A mathematical formulation is described which ensures (1) that the normal component of the photospheric field remains unchanged, (2) that the field is given in the entire corona, (3) that the field remains divergence free, and (4) that electrical currents are introduced into the field. It is demonstrated that a simple radial parameterization of a potential field, comprising a radial stretching of the field, can provide a match for a simple bipolar active region, AR 7999, which crossed the central meridian on 1996 Nov 26. At a coronal height of 30 km, the resulting magnetic field is a non-force free magnetic field with the maximum Lorentz force being on the order of 2.6 x 10(exp -9) dyn resulting from an electric current density of $0.13 mu A/ sq m. This scheme is an important tool in generating a magnetic field solution consistent with the coronal flux tube observations and the observed photospheric magnetic field.

  18. Unsteady wandering magnetic field lines, turbulence and laboratory flux ropes

    NASA Astrophysics Data System (ADS)

    Intrator, T.; Sears, J.; Weber, T.; Liu, D.; Pulliam, D.; Lazarian, A.

    2011-12-01

    We describe earth bound laboratory experiment investigations of patchy, unsteady, bursty, patchy magnetic field structures that are unifying features of magnetic reconnection and turbulence in helio, space and astro physics. Macroscopic field lines occupy cross sectional areas, fill up three dimensional (3D) volumes as flux tubes. They contain mass with Newtonian dynamics that follow magneto-hydro-dynamic (MHD) equations of motion. Flux rope geometry can be ubiquitous in laminar reconnection sheet geometries that are themselves unstable to formation of secondary "islands" that in 3D are really flux ropes. Flux ropes are ubiquitous structures on the sun and the rest of the heliosphere. Understanding the dynamics of flux ropes and their mutual interactions offers the key to many important astrophysical phenomena, including magnetic reconnection and turbulence. We describe laboratory investigations on RSX, where 3D interaction of flux ropes can be studied in great detail. We use experimental probes inside the the flux ropes to measure the magnetic and electric fields, current density, density, temperatures, pressure, and electrostatic and vector plasma potentials. Macroscopic magnetic field lines, unsteady wandering characteristics, and dynamic objects with structure down to the dissipation scale length can be traced from data sets in a 3D volume. Computational approaches are finally able to tackle simple 3D systems and we sketch some intriguing simulation results that are consistent with 3D extensions of typical 2D cartoons for magnetic reconnection and turbulence.

  19. ALLMAG, GDALMG, LINTRA: Computer programs for geomagnetic field and field-line calculations

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

    A set of computer programs has been developed for the calculation of the geomagnetic field and the tracing of field lines in space. The basic subroutine, geocentric ALLMAG, contains coefficients for seven recently-published field models as built-in data statements. At execution time the user can vary the model and/or the time period by simply changing input parameters. Subroutine GDALMG is adapted for input and output in geodetic coordinates. ALLMAG and GDALMG are equivalent to Cain's FIELD and FIELDG, with the added flexibility of the choice of seven models. LINTRA traces field lines from any point in space to a specified altitude intersect in the same or opposite hemisphere, using any of the models contained in ALLMAG. Input is in either geocentric or geodetic coordinates, and output is returned in both. McIlwain's INVAR package, which calculates B and L, has been adapted to use ALLMAG. All programs are described in detail, and sample calculations are given.

  20. Power Line Noise in Transient Electromagnetic (TEM) Data: Identification and Removal in a Practical Field Study.

    NASA Astrophysics Data System (ADS)

    Jernsletten, J. A.

    2004-05-01

    INTRODUCTION: To evaluate the appropriateness of TEM in mapping deep groundwater tables (in Mars analog environmnets), a field study was carried out in the desert ~30 miles SW of Tucson, Arizona. The study was also designed to observe effects of powerline noise on TEM data. The clay-rich soil in the area is quite conductive. The study consisted of 40 in-loop TEM stations, divided into 3 lines, for 4 line-km of data. The survey was carried out by a crew of one person, with square Tx wire loops 100 m on a side, and a ferrite-core magnetic coil Rx antenna in the center of each Tx loop. Maximum useful depth of investigation achieved was ~600 m. TEM DATA: The field area is surrounded by powerlines on all 4 sides: Line 1 has the outside of the first Tx loop under the powerline to the West; Line 2 starts with the powerline to the North passing above just inside its first Tx loop, and ends with the outside of the last station's transmitter loop ~20 m shy of the powerline to the South; finally, Line 3 starts ~50 m East of the powerline to the West, and runs parallel to the powerline to the South along its entire length, at a separation distance of ~70 m. Line 3 was placed largely in an effort to obeserve powerline noise. The decay curve for the first station on Line 1(Line 1/Station 50) is raised above the other curves from Line 1. This is due to the charge (noise) from the adjacent powerline, which is at a distance of ~50 m from the Rx coil. In effect, the transient decay is recorded as being slower than it would be without the presence of the powerline. This also artficially lowers the apparent resistivity, readily observed in Line 1/Station 50 data. These effects are present to a lesser extent (lower magnitude noise) in the data from Line1/Station 150, the second station on Line 1. On the smooth-model inversion cross-section of the data from Line 1, the effects of the powerline noise appears as a pulling up of the low-resistivity water table contact towards the surface

  1. Field line distribution of mass density at geostationary orbit

    NASA Astrophysics Data System (ADS)

    Denton, R. E.; Takahashi, Kazue; Lee, Jimyoung; Zeitler, C. K.; Wimer, N. T.; Litscher, L. E.; Singer, H. J.; Min, Kyungguk

    2015-06-01

    The distribution of mass density along the field lines affects the ratios of toroidal (azimuthally oscillating) Alfvén frequencies, and given the ratios of these frequencies, we can get information about that distribution. Here we assume the commonly used power law form for the field line distribution, ρm = ρm,eq(LRE/R)α, where ρm,eq is the value of the mass density ρm at the magnetic equator, L is the L shell, RE is the Earth's radius, R is the geocentric distance to a point on the field line, and α is the power law coefficient. Positive values of α indicate that ρm increases away from the magnetic equator, zero value indicates that ρm is constant along the magnetic field line, and negative α indicates that there is a local peak in ρm at the magnetic equator. Using 12 years of observations of toroidal Alfvén frequencies by the Geostationary Operational Environmental Satellites, we study the typical dependence of inferred values of α on the magnetic local time (MLT), the phase of the solar cycle as specified by the F10.7 extreme ultraviolet solar flux, and geomagnetic activity as specified by the auroral electrojet (AE) index. Over the mostly dayside range of the observations, we find that α decreases with respect to increasing MLT and F10.7, but increases with respect to increasing AE. We develop a formula that depends on all three parameters, α3Dmodel=2.2+1.3·cos(MLT·15°)+0.0026·AE·cos((MLT-0.8)·15°)+2.1·10-5·AE·F10.7-0.010·F10.7, that models the binned values of α within a standard deviation of 0.3. While we do not yet have a complete theoretical understanding of why α should depend on these parameters in such a way, we do make some observations and speculations about the causes. At least part of the dependence is related to that of ρm,eq; higher α, corresponding to steeper variation with respect to magnetic latitude, occurs when ρm,eq is lower.

  2. Fate of Herbicides and Their Degradation Products Entering a Forested Riparian Buffer Following Herbicides Application to an Adjacent Corn Field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fate of two herbicides, atrazine and metolachlor, were followed as they entered and moved through a forested riparian wetland located in the mid-Atlantic coastal plain of Maryland. The herbicides were applied as pre-emergent treatments to a 20-ha corn field directly upgradient of the riparian w...

  3. Modeling field emitter arrays using nonlinear line charge distribution

    NASA Astrophysics Data System (ADS)

    Biswas, Debabrata; Singh, Gaurav; Kumar, Raghwendra

    2016-09-01

    Modeling high aspect ratio field emitter arrays is a computational challenge due to the enormity of the resources involved. The line charge model (LCM) provides an alternate semi-analytical tool that has been used to model both infinite as well as finite sized arrays. It is shown that the linearly varying charge density used in the LCM generically mimics ellipsoidal emitters rather than a Cylindrical-Post-with-an-Ellipsoidal-Tip (CPET) that is typical of nanowires. Furthermore, generalizing the charge density beyond the linear regime allows for modeling shapes that are closer to a CPET. Emitters with a fixed base radius and a fixed apex radius are studied with a view to understanding the effect of nonlinearity on the tip enhancement factor and the emitter current in each case. Furthermore, an infinite square array of the CPET emitters is studied using the nonlinear line charge model, each having a height h =1500 μm and a base radius b =1.5 μm . It is found that for moderate external field strengths ( 0.3 -0.4 V /μm ), the array current density falls sharply for lattice spacings smaller than 4/3 h . Beyond this value, the maximal array current density can be observed over a range of lattice spacings and falls gradually thereafter.

  4. Gene expression in normal-appearing tissue adjacent to prostate cancers are predictive of clinical outcome: evidence for a biologically meaningful field effect

    PubMed Central

    Magi-Galluzzi, Cristina; Maddala, Tara; Falzarano, Sara Moscovita; Cherbavaz, Diana B.; Zhang, Nan; Knezevic, Dejan; Febbo, Phillip G.; Lee, Mark; Lawrence, Hugh Jeffrey; Klein, Eric A.

    2016-01-01

    Purpose We evaluated gene expression in histologically normal-appearing tissue (NT) adjacent to prostate tumor in radical prostatectomy specimens, assessing for biological significance based on prediction of clinical recurrence (cR - metastatic disease or local recurrence). Results A total of 410 evaluable patients had paired tumor and NT. Fortysix genes, representing diverse biological pathways (androgen signaling, stromal response, stress response, cellular organization, proliferation, cell adhesion, and chromatin remodeling) were associated with cR in NT (FDR < 20%), of which 39 concordantly predicted cR in tumor (FDR < 20%). Overall GPS and its stromal response and androgen-signaling gene group components also significantly predicted time to cR in NT (RM-corrected HR/20 units = 1.25; 95% CI: 1.01-1.56; P = 0.024). Experimental Design Expression of 732 genes was measured by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) separately in tumor and adjacent NT specimens from 127 patients with and 374 without cR following radical prostatectomy for T1/T2 prostate cancer. A 17-gene expression signature (Genomic Prostate Score [GPS]), previously validated to predict aggressive prostate cancer when measured in tumor tissue, was also assessed using pre-specified genes and algorithms. Analysis used Cox proportional hazards models, Storey's false discovery rate (FDR) control, and regression to the mean (RM) correction. Conclusions Gene expression profiles, including GPS, from NT adjacent to tumor can predict prostate cancer outcome. These findings suggest that there is a biologically significant field effect in primary prostate cancer that is a marker for aggressive disease. PMID:27121323

  5. Constructing the Coronal Magnetic Field by Correlating Parameterized Magnetic Field Lines with Observed Coronal Plasma Structures

    NASA Technical Reports Server (NTRS)

    Allen, Gary G.; Alexander, David

    1999-01-01

    A method is presented for constructing the coronal magnetic field from photospheric magnetograms and observed coronal loops. A set of magnetic field lines generated from magnetogram data is parameterized and then deformed by varying the parameterized values. The coronal flux tubes associated with this field are adjusted until the correlation between the field lines and the observed coronal loops is maximized. A mathematical formulation is described which ensures that (1) the normal component of the photospheric field remains unchanged, (2) the field is given in the entire corona over an active region, (3) the field remains divergence-free, and 4electric currents are introduced into the field. It is demonstrated that a parameterization of a potential field, comprising a radial stretching of the field, can provide a match for a simple bipolar active region, AR 7999, which crossed the central meridian on 1996 November 26. The result is a non-force-free magnetic field with the Lorentz force being of the order of 10(exp -5.5) g per s(exp 2) resulting from an electric current density of 0.79 micro A per m(exp 2). Calculations show that the plasma beta becomes larger than unity at a strong non-radial currents requires low height of about 0.25 solar radii supporting the non-force-free conclusion. The presence of such strong non-radial currents requires large transverse pressure gradients fo maintain a magnetostatic atmosphere, required by the relatively persistent nature of the coronal structures observed in AR 7999. This scheme is an important tool in generating a magnetic field solution consistent with the coronal flux tube observations and the observed photospheric magnetic field.

  6. Impact of punctual flat magnetic shear on the field line transport

    NASA Astrophysics Data System (ADS)

    Abud, C. V.; Caldas, I. L.

    2015-06-01

    We investigate the magnetic field line transport for tokamak equilibria with monotonic magnetic shear perturbed by resonant fields. We show that when the local profile is flat at the plasma edge a transport barrier can be created leading to a field line transport reduction. This transport reduction is due to the field lines topological modifications, caused by a local flattened profile that reduces the global field lines escape pattern. The results are obtained by applying a symplectic map that describes perturbed magnetic field lines in large aspect ratio tokamaks.

  7. Invertebrates and vegetation of field margins adjacent to crops subject to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide-tolerant crops.

    PubMed Central

    Roy, D B; Bohan, D A; Haughton, A J; Hill, M O; Osborne, J L; Clark, S J; Perry, J N; Rothery, P; Scott, R J; Brooks, D R; Champion, G T; Hawes, C; Heard, M S; Firbank, L G

    2003-01-01

    The effects of management of genetically modified herbicide-tolerant (GMHT) crops on adjacent field margins were assessed for 59 maize, 66 beet and 67 spring oilseed rape sites. Fields were split into halves, one being sown with a GMHT crop and the other with the equivalent conventional non-GMHT crop. Margin vegetation was recorded in three components of the field margins. Most differences were in the tilled area, with fewer smaller effects mirroring them in the verge and boundary. In spring oilseed rape fields, the cover, flowering and seeding of plants were 25%, 44% and 39% lower, respectively, in the GMHT uncropped tilled margins. Similarly, for beet, flowering and seeding were 34% and 39% lower, respectively, in the GMHT margins. For maize, the effect was reversed, with plant cover and flowering 28% and 67% greater, respectively, in the GMHT half. Effects on butterflies mirrored these vegetation effects, with 24% fewer butterflies in margins of GMHT spring oilseed rape. The likely cause is the lower nectar supply in GMHT tilled margins and crop edges. Few large treatment differences were found for bees, gastropods or other invertebrates. Scorching of vegetation by herbicide-spray drift was on average 1.6% on verges beside conventional crops and 3.7% beside GMHT crops, the difference being significant for all three crops. PMID:14561320

  8. Dynamics of the Open Closed Field Line Boundary

    NASA Astrophysics Data System (ADS)

    Spanswick, E.; Roy, E.; Nishimura, T.; Unick, C.; Jackel, B. J.; Donovan, E.

    2015-12-01

    In most cases, large-scale features of the auroral distribution are the projection, along magnetic field lines, of corresponding magnetospheric features. The poleward boundary of the oval is a key example of such a feature. At almost all local times, this is most often interpreted as the ionospheric marker of the latitudinal transition between open lobe and closed central plasma sheet field lines. Earlier work by Blanchard et al. [J. Geophys. Res., 1995 & 1997] used ground-based photometric observations of 630 nm "redline" aurora and in situ particle observations from simultaneous DMSP overflights to demonstrate that the poleward boundary of the redline aurora is a particularly robust signature of the poleward boundary of the plasma sheet. Owing to the orbits of the DMSP spacecraft and the relative newness of the photometer program (CANOPUS) that provided the optical observations, the Blanchard results represent a limited sampling of magnetic local time and a limited number of events. In this paper we revisit the Blanchard et al study, using particle data from the NASA FAST satellite and the DMSP program, together with redline observations obtained by ground-based All-Sky Imagers. Our results indicate that the Blanchard technique for identifying the polar cap boundary holds true for essentially all magnetic local times on the night side, but that the picture is more nuanced than previously appreciated. Here we present these results, and discuss specific examples where the technique does not work (and explore why). Furthermore, this work is motivated by a new extensive network of highly sensitive redline imagers that has been deployed across northern and central Canada which provides high time resolution large-scale snapshots of the instantaneous polar cap boundary. This in turn enables us to explore magnetospheric dynamics at the interface between the lobe and central plasma sheet in fundamentally new and exciting ways.

  9. Tectonic pattern of the Mendeleev Ridge and adjacent basins: results of joint analysis of potential fields and recent Russian seismic data

    NASA Astrophysics Data System (ADS)

    Chernykh, Andrey; Astafurova, Ekaterina; Korneva, Maria; Egorova, Alena; Redko, Anton; Glebovsky, Vladimir

    2014-05-01

    The work was performed under Russian Federation State Geological mapping at a scale of 1:1 000 000 and UNCLOS programs. The study area is located between 76N-84N and 156E-168W and covers the Mendeleev Ridge, adjacent Podvodnikov, Mendeleev, Chukchi Basins and northern part of the East-Siberian Sea shelf. It is characterized by very poor magnetic and gravity data coverage. Majority of airborne magnetic and on-ice gravity surveys were carried out in the region about 40 years ago and have low spatial resolution and poor navigation. Seismic data collected earlier in the study area are presented by sparse lines of historical seismic reflection soundings and by results of deep seismic refraction and reflection observations along several geotransects. Hence, conclusions concerning tectonic structure and spatial relation of the Mendeleev Ridge with adjacent geological structures up to present day remain speculative. Joint analysis of recent seismic reflection and refraction data collected during Russian expeditions «Arctic-2011» and «Arctic-2012» with mentioned above geophysical information allowed to clarify the contours of geological structures in the study area and reveal some new peculiarities of their tectonic pattern. Particularly complex tectonic structure of the Mendeleev Ridge, changing from it's southern to the northern part and represented by two main systems of tectonic displacements is discovered. The first fault system comprises horsts/graben-bounding faults oriented preferably in N-S direction. The second system is presented by faults of NW-SE direction disturbing the first one. In the southern part of the Mendeleev Ridge such faults are the strike-slip faults with small horizontal displacements. Starting from the central part of the ridge and further to the north, displacements along strike-slip faults become progressively more pronounced and have sinistral character. In the northern part of the ridge a pull-apart structures are recognized which

  10. MAGNETIC FIELD LINE RANDOM WALK IN ISOTROPIC TURBULENCE WITH ZERO MEAN FIELD

    SciTech Connect

    Sonsrettee, W.; Ruffolo, D.; Snodin, A. P.; Wongpan, P.; Subedi, P.; Matthaeus, W. H.; Chuychai, P. E-mail: david.ruf@mahidol.ac.th E-mail: pat.wongpan@postgrad.otago.ac.nz E-mail: prasub@udel.edu

    2015-01-01

    In astrophysical plasmas, magnetic field lines often guide the motions of thermal and non-thermal particles. The field line random walk (FLRW) is typically considered to depend on the Kubo number R = (b/B {sub 0})(ℓ{sub ∥}/ℓ ) for rms magnetic fluctuation b, large-scale mean field B {sub 0}, and parallel and perpendicular coherence scales ℓ{sub ∥} and ℓ , respectively. Here we examine the FLRW when R → ∞ by taking B {sub 0} → 0 for finite b{sub z} (fluctuation component along B {sub 0}), which differs from the well-studied route with b{sub z} = 0 or b{sub z} << B {sub 0} as the turbulence becomes quasi-two-dimensional (quasi-2D). Fluctuations with B {sub 0} = 0 are typically isotropic, which serves as a reasonable model of interstellar turbulence. We use a non-perturbative analytic framework based on Corrsin's hypothesis to determine closed-form solutions for the asymptotic field line diffusion coefficient for three versions of the theory, which are directly related to the k {sup –1} or k {sup –2} moment of the power spectrum. We test these theories by performing computer simulations of the FLRW, obtaining the ratio of diffusion coefficients for two different parameterizations of a field line. Comparing this with theoretical ratios, the random ballistic decorrelation version of the theory agrees well with the simulations. All results exhibit an analog to Bohm diffusion. In the quasi-2D limit, previous works have shown that Corrsin-based theories deviate substantially from simulation results, but here we find that as B {sub 0} → 0, they remain in reasonable agreement. We conclude that their applicability is limited not by large R, but rather by quasi-two-dimensionality.

  11. Geology, geochronology, and paleogeography of the southern Sonoma volcanic field and adjacent areas, northern San Francisco Bay region, California

    USGS Publications Warehouse

    Wagner, D.L.; Saucedo, G.J.; Clahan, K.B.; Fleck, R.J.; Langenheim, V.E.; McLaughlin, R.J.; Sarna-Wojcicki, A. M.; Allen, J.R.; Deino, A.L.

    2011-01-01

    Recent geologic mapping in the northern San Francisco Bay region (California, USA) supported by radiometric dating and tephrochronologic correlations, provides insights into the framework geology, stratigraphy, tectonic evolution, and geologic history of this part of the San Andreas transform plate boundary. There are 25 new and existing radiometric dates that define three temporally distinct volcanic packages along the north margin of San Pablo Bay, i.e., the Burdell Mountain Volcanics (11.1 Ma), the Tolay Volcanics (ca. 10-8 Ma), and the Sonoma Volcanics (ca. 8-2.5 Ma). The Burdell Mountain and the Tolay Volcanics are allochthonous, having been displaced from the Quien Sabe Volcanics and the Berkeley Hills Volcanics, respectively. Two samples from a core of the Tolay Volcanics taken from the Murphy #1 well in the Petaluma oilfield yielded ages of 8.99 ?? 0.06 and 9.13 ?? 0.06 Ma, demonstrating that volcanic rocks exposed along Tolay Creek near Sears Point previously thought to be a separate unit, the Donnell Ranch volcanics, are part of the Tolay Volcanics. Other new dates reported herein show that volcanic rocks in the Meacham Hill area and extending southwest to the Burdell Mountain fault are also part of the Tolay Volcanics. In the Sonoma volcanic field, strongly bimodal volcanic sequences are intercalated with sediments. In the Mayacmas Mountains a belt of eruptive centers youngs to the north. The youngest of these volcanic centers at Sugarloaf Ridge, which lithologically, chemically, and temporally matches the Napa Valley eruptive center, was apparently displaced 30 km to the northwest by movement along the Carneros and West Napa faults. The older parts of the Sonoma Volcanics have been displaced at least 28 km along the RodgersCreek fault since ca. 7 Ma. The Petaluma Formation also youngs to the north along the Rodgers Creek-Hayward fault and the Bennett Valley fault. The Petaluma basin formed as part of the Contra Costa basin in the Late Miocene and was

  12. Nuclear mean field on and near the drip lines

    NASA Astrophysics Data System (ADS)

    Otsuka, Takaharu; Fukunishi, Nobuhisa

    1996-01-01

    We discuss two subjects related to the structure of nuclei near the drip lines. The first is the vanishing of N = 20 magic structure in Z ≪ N = 20 nuclei. Large-scale state-of-the-art shell-model calculations with 2sld and lower 2plf shells are shown to present a unified description of N = 20 isotones with Z = 10-20, covering both stable and unstable nuclei. The calculations demonstrate that, although the N = 20 closed-shell structure remains for Z ≥ 14, the N = 20 closed-shell structure vanishes naturally towards nuclei with Z ≤ 12, giving rise to various anomalous features including those in 32Mg and 31Na. It is suggested that, in these nuclei, the deformed mean field overcomes the shell gap created by the spherical mean potential. Furthermore, the almost perfect agreement with a recent experiment is presented for the B(E2; 0 1+ → 2 1+) value of 32Mg. The second part is devoted to the mean field for loosely bound neutrons. The variational shell model (VSM) is explained with an application to the anomalous ground state of 11Be. The VSM has been proposed recently to describe the structure of neutron-rich unstable nuclei. Contrary to the failure of spherical Hartree-Fock, the anomalous {1}/{2}+ ground state and its neutron halo are reproduced with Skyrme SIII interaction. This state is bound due to dynamical coupling between the core and the loosely bound neutron which oscillates between 2 s{1}/{2} and l d{5}/{2} orbits. The direct neutron capture is discussed briefly in its relation to the neutron halo.

  13. Plasma confinement by magnetic field with convex-concave field lines

    NASA Astrophysics Data System (ADS)

    Tsventoukh, Mikhail M.; Krashevskaya, Galina V.; Prishvitsyn, Alexander S.

    2015-06-01

    It has been found that plasma confinement by the magnetic field of alternating-sign curvature with convex-concave field lines results in a strong stabilizing action against convective (flute-interchange) perturbations. For simple combinations of axisymmetric mirrors and cusps the calculations according to the kinetic stability criterion give strongly, centrally peaked stable plasma pressure profiles instead of shallow ones. For the experimental research of this effect, a compact magnetic confinement device has been modified by adding of the external current coil to fulfil the field-line curvature requirements. The critical convectively-stable plasma pressure profiles calculation in this experimental geometry and the probe measurements of the spatial plasma distribution in the new magnetic configuration of alternating-sign curvature have been performed. The experimental results give some support for a conclusion that there is an increase in the ion saturation current at the region near the minimum of the specific volume min ∫dl/B. This region corresponds to the average minimum in the second adiabatic invariant, and the kinetic description predicts the stable pressure profile peaking here due to reduction of charge separation by particle drift in alternating-sign curvature.

  14. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission lines: Permanent field repair of leaks. 192.717 Section 192.717 Transportation Other Regulations Relating to Transportation (Continued... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak...

  15. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Permanent field repair of leaks. 192.717 Section 192.717 Transportation Other Regulations Relating to Transportation (Continued... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak...

  16. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Permanent field repair of leaks. 192.717 Section 192.717 Transportation Other Regulations Relating to Transportation (Continued... § 192.717 Transmission lines: Permanent field repair of leaks. Each permanent field repair of a leak...

  17. Research on the Error Characteristics of a 110 kV Optical Voltage Transformer under Three Conditions: In the Laboratory, Off-Line in the Field and During On-Line Operation

    PubMed Central

    Xiao, Xia; Hu, Haoliang; Xu, Yan; Lei, Min; Xiong, Qianzhu

    2016-01-01

    Optical voltage transformers (OVTs) have been applied in power systems. When performing accuracy performance tests of OVTs large differences exist between the electromagnetic environment and the temperature variation in the laboratory and on-site. Therefore, OVTs may display different error characteristics under different conditions. In this paper, OVT prototypes with typical structures were selected to be tested for the error characteristics with the same testing equipment and testing method. The basic accuracy, the additional error caused by temperature and the adjacent phase in the laboratory, the accuracy in the field off-line, and the real-time monitoring error during on-line operation were tested. The error characteristics under the three conditions—laboratory, in the field off-line and during on-site operation—were compared and analyzed. The results showed that the effect of the transportation process, electromagnetic environment and the adjacent phase on the accuracy of OVTs could be ignored for level 0.2, but the error characteristics of OVTs are dependent on the environmental temperature and are sensitive to the temperature gradient. The temperature characteristics during on-line operation were significantly superior to those observed in the laboratory. PMID:27537895

  18. Magnetic Field-Line Lengths in Interplanetary Coronal Mass Ejections Inferred From Energetic Electron Events (Postprint)

    DTIC Science & Technology

    2012-05-03

    AFRL-RV-PS- AFRL-RV-PS- TP-2012-0026 TP-2012-0026 MAGNETIC FIELD -LINE LENGTHS IN INTERPLANETARY CORONAL MASS EJECTIONS INFERRED FROM... Magnetic Field -Line Lengths in Interplanetary Coronal Mass Ejections Inferred 5a. CONTRACT NUMBER In-House From Energetic Electron Events... MAGNETIC FIELD -LINE LENGTHS IN INTERPLANETARY CORONAL MASS EJECTIONS INFERRED FROM ENERGETIC ELECTRON EVENTS S. W. Kahler1, D. K. Haggerty2, and I. G

  19. The distant magnetotail's response to a strong interplanetary magnetic field By - Twisting, flattening, and field line bending

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.; Siscoe, G. L.; Slavin, J. A.; Smith, E. J.; Tsurutani, B. T.; Lepping, R. P.

    1985-01-01

    During an interval of strong interplanetary magnetic field (IMF) By, while ISEE 3 was in the distant magnetotail, the north lobe was observed south of the ecliptic plane. Lobe field lines were strongly bent in the direction of the IMF, and a dense boundary layer plasma was observed. During the interval, magnetopause normals pointed in the z direction, although ISEE 3 was near the dawnside ecliptic plane. The observations are interpreted in terms of field line bending within a twisted and flattened magnetotail.

  20. LINE PROFILE ASYMMETRIES AND THE CHROMOSPHERIC FLARE VELOCITY FIELD

    SciTech Connect

    Kuridze, D.; Mathioudakis, M.; Kennedy, M.; Keenan, F. P.; Simões, P. J. A.; Voort, L. Rouppe van der; Fletcher, L.; Carlsson, M.; Jafarzadeh, S.; Allred, J. C.; Kowalski, A. F.; Graham, D.

    2015-11-10

    The asymmetries observed in the line profiles of solar flares can provide important diagnostics of the properties and dynamics of the flaring atmosphere. In this paper the evolution of the Hα and Ca ii λ8542 lines are studied using high spatial, temporal, and spectral resolution ground-based observations of an M1.1 flare obtained with the Swedish 1 m Solar Telescope. The temporal evolution of the Hα line profiles from the flare kernel shows excess emission in the red wing (red asymmetry) before flare maximum and excess in the blue wing (blue asymmetry) after maximum. However, the Ca ii λ8542 line does not follow the same pattern, showing only a weak red asymmetry during the flare. RADYN simulations are used to synthesize spectral line profiles for the flaring atmosphere, and good agreement is found with the observations. We show that the red asymmetry observed in Hα is not necessarily associated with plasma downflows, and the blue asymmetry may not be related to plasma upflows. Indeed, we conclude that the steep velocity gradients in the flaring chromosphere modify the wavelength of the central reversal in the Hα line profile. The shift in the wavelength of maximum opacity to shorter and longer wavelengths generates the red and blue asymmetries, respectively.

  1. Characterization of the Coupling Between Adjacent Finite Ground Coplanar (FGC) Waveguides

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Katehi, Linda P. B.; Tentzeris, Emmanouil M.

    1997-01-01

    Coupling between adjacent Finite Ground Coplanar (FGC) waveguides as a function of the line geometry is presented for the first time. A two Dimension-Finite Difference Time Domain (2D-FDTD) analysis and measurements are used to show that the coupling decreases as the line to line separation and the grOUnd plane width increases. Furthermore, it is shown that for a given spacing between the center lines of two FGC lines, the coupling is lower if the ground plane width is smaller Lastly, electric field plots generated from the 2D-FDTD technique are presented which demonstrate a strong slotline mode is established in the coupled FGC line.

  2. Field Calibration of the δ11B-pH Proxy in Corals and Calcified Algae at a Shallow Hydrothermal Vent and Adjacent Coral Reef

    NASA Astrophysics Data System (ADS)

    Day, R. D.; Christopher, S. J.; Young, C.; Brainard, R. E.; Butterfield, D. A.; Stewart, J.

    2015-12-01

    There is increasing interest in using the boron isotopic composition (δ11B) of biogenic carbonates as a proxy for seawater pH to better understand recent ocean acidification. The utility of this proxy hinges on the production of robust species-specific δ11B-pH calibrations; yet, challenges remain in the interpretation of boron isotope data due to biases introduced by physiological, environmental, and analytical factors. The shallow hydrothermal vents in the Maug Islands caldera (Marianas Islands) and the adjacent coral reefs exhibit a localized gradient > 1 pH unit. This gradient was used as a natural laboratory to assess the efficacy of using skeletal δ11B in a variety of corals (Porites spp., Pocillipora spp., Acropora spp.) and calcified algae (Halimeda spp. and Corallinales) as biosensors of seawater pH. Three sites were selected representing oceanic background, intermediate, and low pH zones, and direct seawater pH measurements were recorded for 3 months using SeaFETs. Corals and algae growing naturally in situ were collected from these 3 sites. In addition, corals and algae collected from a background location were stained and transplanted to these sites and allowed to grow for 3 months. Measurements of δ11B in skeletal material made by multi-collector inductively coupled mass spectrometry are compared to direct seawater pH measurements to assess the sensitivity and robustness of the δ11B proxy in these candidate biosensors in predicting ambient pH in the field. These data will inform ongoing efforts by the Archive of Coral Ecosystem Specimens (ACES) to collect marine carbonates for analysis and archival in the Marine Environmental Specimen Bank for broad-scale, long-term monitoring of ocean acidification and the associated impacts to coral reefs. Concurrent analyses of other trace elements, heavy metals, and isotopes in these samples will also be performed to assess their utility as biosensors for additional water chemistry parameters on coral reefs.

  3. Different hydraulic responses to the 2008 Wenchuan and 2011 Tohoku earthquakes in two adjacent far-field wells: the effect of shales on aquifer lithology

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Fu, Li-Yun; Ma, Yuchuan; Hu, Junhua

    2016-11-01

    Zuojiazhuang and Baodi are two adjacent wells ( 50 km apart) in northern China. The large 2008 M w 7.9 Wenchuan and 2011 M w 9.1 Tohoku earthquakes induced different co-seismic water-level responses in these far-field (>1000 km) wells. The co-seismic water-level changes in the Zuojiazhuang well exhibited large amplitudes ( 2 m), whereas those in the Baodi well were small and unclear ( 0.05 m). The mechanism of the different co-seismic hydraulic responses in the two wells needs to be revealed. In this study, we used the barometric responses in different frequency domains and the phase shifts and amplitude ratios of the tidal responses (M2 wave), together with the well logs, to explain this inconformity. Our calculations show that the co-seismic phase shifts of the M2 wave decreased or remained unchanged in the Baodi well, which was quite different from the Zuojiazhuang well and from the commonly accepted phenomena. According to the well logs, the lithology of the Baodi well is characterized by the presence of a significant amount of shale. The low porosity/permeability of shale in the Baodi well could be the cause for the unchanged and decreased phase shifts and tiny co-seismic water-level responses. In addition, shale is one of the causes of positive phase shifts and indicates a vertical water-level flow, which may be due to a semi-confined aquifer or the complex and anisotropic fracturing of shale.

  4. Measurements of solar magnetic fields by Fourier transform techniques. II - Saturated and blended lines

    NASA Technical Reports Server (NTRS)

    Tarbell, T. D.; Title, A. M.

    1976-01-01

    Fourier techniques have been exhaustively calibrated using Unno's (1956) results for the absorption profile of a simple Zeeman triplet. If a simple transformation is applied to the normalized line depths, then magnetic-field strengths and inclination angles can be measured very accurately from noisy saturated line profiles. Systematic errors caused by saturation effects can be estimated and reduced by varying one parameter. When a significant fraction of the line profile is unsplit and unpolarized, large errors may be made in measurements of low fields, unless the line is sufficiently weak. For a weak line, a vertical field of 1600 gauss can be measured to 10% accuracy even when 70% of the line profile is stray light. These stray-light errors are troublesome in measuring fields of gaps and pores but not sunspots. Numerical results of the error analysis are presented graphically.

  5. 49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: Permanent field repair of imperfections and damages. 192.713 Section 192.713 Transportation Other Regulations Relating to Transportation... Maintenance § 192.713 Transmission lines: Permanent field repair of imperfections and damages. (a)...

  6. 49 CFR 192.715 - Transmission lines: Permanent field repair of welds.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Permanent field repair of welds. 192.715 Section 192.715 Transportation Other Regulations Relating to Transportation (Continued... § 192.715 Transmission lines: Permanent field repair of welds. Each weld that is unacceptable...

  7. 49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Permanent field repair of imperfections and damages. 192.713 Section 192.713 Transportation Other Regulations Relating to Transportation... Maintenance § 192.713 Transmission lines: Permanent field repair of imperfections and damages. (a)...

  8. 49 CFR 192.715 - Transmission lines: Permanent field repair of welds.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission lines: Permanent field repair of welds. 192.715 Section 192.715 Transportation Other Regulations Relating to Transportation (Continued... § 192.715 Transmission lines: Permanent field repair of welds. Each weld that is unacceptable...

  9. 49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission lines: Permanent field repair of imperfections and damages. 192.713 Section 192.713 Transportation Other Regulations Relating to Transportation... Maintenance § 192.713 Transmission lines: Permanent field repair of imperfections and damages. (a)...

  10. 49 CFR 192.715 - Transmission lines: Permanent field repair of welds.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission lines: Permanent field repair of welds. 192.715 Section 192.715 Transportation Other Regulations Relating to Transportation (Continued... § 192.715 Transmission lines: Permanent field repair of welds. Each weld that is unacceptable...

  11. 49 CFR 192.715 - Transmission lines: Permanent field repair of welds.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Permanent field repair of welds. 192.715 Section 192.715 Transportation Other Regulations Relating to Transportation (Continued... § 192.715 Transmission lines: Permanent field repair of welds. Each weld that is unacceptable...

  12. 49 CFR 192.715 - Transmission lines: Permanent field repair of welds.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission lines: Permanent field repair of welds. 192.715 Section 192.715 Transportation Other Regulations Relating to Transportation (Continued... § 192.715 Transmission lines: Permanent field repair of welds. Each weld that is unacceptable...

  13. Inference of Equatorial Field-Line Integrated Electron Density Values Using Whistlers,

    DTIC Science & Technology

    1984-08-01

    Introduction During the post sunset period the equatorial Ionosphere Is known to be turbulent over scale sizes from tens of kilometws to tens of...trace will be associated with 3/2 of a field line, the third trace will be associated with 5/2 of a field line, etc. Ve should emphasize that there Is no

  14. Random walk of magnetic field-lines for different values of the energy range spectral index

    SciTech Connect

    Shalchi, A.; Kourakis, I.

    2007-11-15

    An analytical nonlinear description of field-line wandering in partially statistically magnetic systems was proposed recently. In this article the influence of the wave spectrum in the energy range onto field-line random walk is investigated by applying this formulation. It is demonstrated that in all considered cases we clearly obtain a superdiffusive behavior of the field-lines. If the energy range spectral index exceeds unity a free-streaming behavior of the field-lines can be found for all relevant length-scales of turbulence. Since the superdiffusive results obtained for the slab model are exact, it seems that superdiffusion is the normal behavior of field-line wandering.

  15. ON FIBRILS AND FIELD LINES: THE NATURE OF Hα FIBRILS IN THE SOLAR CHROMOSPHERE

    SciTech Connect

    Leenaarts, Jorrit; Carlsson, Mats; Voort, Luc Rouppe van der E-mail: mats.carlsson@astro.uio.no

    2015-04-01

    Observations of the solar chromosphere in the line core of the Hα line show dark elongated structures called fibrils that show swaying motion. We performed a three-dimensional radiation-MHD simulation of a network region and computed synthetic Hα images from this simulation to investigate the relation between fibrils and the magnetic field lines in the chromosphere. The periods, amplitudes, and phase speeds of the simulated fibrils are consistent with observations. We find that some fibrils trace out the same field line along the fibril’s length, while other fibrils sample different field lines at different locations along their length. Fibrils sample the same field lines on a timescale of ∼200 s. This is shorter than their own lifetime. Fibril-threading field lines carry slow-mode waves, as well as transverse waves propagating with the Alfvén speed. Transverse waves propagating in opposite directions cause an interference pattern with complex apparent phase speeds. The relationship between fibrils and field lines is governed by constant migration and swaying of the field lines, their mass loading and draining, and their visibility in Hα. Field lines are visible where they lie close to the optical depth unity surface. The location of the latter is at a height at which the column mass reaches a certain fixed value. The visibility of the field line is thus determined by its own mass density and by the mass density of the material above it. Using the swaying motion of fibrils as a tracer of chromospheric transverse oscillations must be done with caution.

  16. Electric field simulation and measurement of a pulse line ion accelerator

    NASA Astrophysics Data System (ADS)

    Shen, Xiao-Kang; Zhang, Zi-Min; Cao, Shu-Chun; Zhao, Hong-Wei; Wang, Bo; Shen, Xiao-Li; Zhao, Quan-Tang; Liu, Ming; Jing, Yi

    2012-07-01

    An oil dielectric helical pulse line to demonstrate the principles of a Pulse Line Ion Accelerator (PLIA) has been designed and fabricated. The simulation of the axial electric field of an accelerator with CST code has been completed and the simulation results show complete agreement with the theoretical calculations. To fully understand the real value of the electric field excited from the helical line in PLIA, an optical electric integrated electric field measurement system was adopted. The measurement result shows that the real magnitude of axial electric field is smaller than that calculated, probably due to the actual pitch of the resister column which is much less than that of helix.

  17. Effects of conductor sag on spatial distribution of power line magnetic field

    SciTech Connect

    Mamishev, A.V.; Nevels, R.D.; Russell, B.D.

    1996-07-01

    Traditional extremely low frequency (ELF) magnetic field computation techniques assume that the current carrying power line conductors are straight horizontal wires. This assumption results in a model whose magnetic fields are distorted from those produced in reality. An exact solution and an approximation are proposed for modeling magnetic fields produced by the sagged conductors of power lines, by taking advantage of the fact that the equation of the catenary exactly describes the line sag. The proposed approaches differ in the required computational burden and in the precision of the results. A field mapping measurement example illustrates the applicability and the need for this analysis. The relative importance of the catenary effect is discussed.

  18. On the effects of magnetic field line topology on the energy propagation in the solar corona

    NASA Astrophysics Data System (ADS)

    Candelaresi, Simon

    2016-05-01

    Using the MHD approximation, we study the propagation of energy from photospheric footpoint motions into the corona. Our model consists of a magnetic carpet with closed and open magnetic field lines. Magnetic null points are present close at the surface. The applied photospheric driver twists the field into a topologically non-trivial configuration which leads to reconnection and a change in field line topology. Prior to this event, the energy propagation into the corona is largely inhibited due to closed field lines. After such events the energy is free to propagate into the corona.

  19. Resolving magnetic field line stochasticity and parallel thermal transport in MHD simulations

    SciTech Connect

    Nishimura, Y.; Callen, J.D.; Hegna, C.C.

    1998-12-31

    Heat transport along braided, or chaotic magnetic field lines is a key to understand the disruptive phase of tokamak operations, both the major disruption and the internal disruption (sawtooth oscillation). Recent sawtooth experimental results in the Tokamak Fusion Test Reactor (TFTR) have inferred that magnetic field line stochasticity in the vicinity of the q = 1 inversion radius plays an important role in rapid changes in the magnetic field structures and resultant thermal transport. In this study, the characteristic Lyapunov exponents and spatial correlation of field line behaviors are calculated to extract the characteristic scale length of the microscopic magnetic field structure (which is important for net radial global transport). These statistical values are used to model the effect of finite thermal transport along magnetic field lines in a physically consistent manner.

  20. Magnetic Field Line Random Walk in Isotropic Turbulence with Varying Mean Field

    NASA Astrophysics Data System (ADS)

    Sonsrettee, W.; Subedi, P.; Ruffolo, D.; Matthaeus, W. H.; Snodin, A. P.; Wongpan, P.; Chuychai, P.; Rowlands, G.; Vyas, S.

    2016-08-01

    In astrophysical plasmas, the magnetic field line random walk (FLRW) plays an important role in guiding particle transport. The FLRW behavior is scaled by the Kubo number R=(b/{B}0)({{\\ell }}\\parallel /{{\\ell }}\\perp ) for rms magnetic fluctuation b, large-scale mean field {{\\boldsymbol{B}}}0, and coherence scales parallel ({{\\ell }}\\parallel ) and perpendicular ({{\\ell }}\\perp ) to {{\\boldsymbol{B}}}0. Here we use a nonperturbative analytic framework based on Corrsin’s hypothesis, together with direct computer simulations, to examine the R-scaling of the FLRW for varying B 0 with finite b and isotropic fluctuations with {{\\ell }}\\parallel /{{\\ell }}\\perp =1, instead of the well-studied route of varying {{\\ell }}\\parallel /{{\\ell }}\\perp for b \\ll {B}0. The FLRW for isotropic magnetic fluctuations is also of astrophysical interest regarding transport processes in the interstellar medium. With a mean field, fluctuations may have variance anisotropy, so we consider limiting cases of isotropic variance and transverse variance (with b z = 0). We obtain analytic theories, and closed-form solutions for extreme cases. Padé approximants are provided to interpolate all versions of theory and simulations to any B 0. We demonstrate that, for isotropic turbulence, Corrsin-based theories generally work well, and with increasing R there is a transition from quasilinear to Bohm diffusion. This holds even with b z = 0, when different routes to R\\to ∞ are mathematically equivalent; in contrast with previous studies, we find that a Corrsin-based theory with random ballistic decorrelation works well even up to R = 400, where the effects of trapping are barely perceptible in simulation results.

  1. Electric currents and voltage drops along auroral field lines

    NASA Technical Reports Server (NTRS)

    Stern, D. P.

    1983-01-01

    An assessment is presented of the current state of knowledge concerning Birkeland currents and the parallel electric field, with discussions focusing on the Birkeland primary region 1 sheets, the region 2 sheets which parallel them and appear to close in the partial ring current, the cusp currents (which may be correlated with the interplanetary B(y) component), and the Harang filament. The energy required by the parallel electric field and the associated particle acceleration processes appears to be derived from the Birkeland currents, for which evidence is adduced from particles, inverted V spectra, rising ion beams and expanded loss cones. Conics may on the other hand signify acceleration by electrostatic ion cyclotron waves associated with beams accelerated by the parallel electric field.

  2. Calculation and measurement of electric field under HVDC transmission lines

    NASA Astrophysics Data System (ADS)

    Kasdi, A.; Zebboudj, Y.; Yala, H.

    2007-03-01

    A stable corona discharge in a two conductors-to-plane configuration is analysed in this paper. A linear biased probe, without end-effect, has been adapted to a linear geometry and is used for the first time to measure the ground-plane current density and electric field during the bipolar corona. The values of the electric field and the current density are maximum under the two coronating conductors and decrease when moving away from them. Furthermore, a hybrid technique is developed to obtain a general solution of the governing equations of the coupled space-charge and electric field problem. The technique is to use the finite-element method (FEM) to solve Poisson's equation, and the method of characteristic (MOC) to find the charge density from a current-continuity relation. The model avoids resorting to the Deutsch assumption. The computed values are in good agreement with experimental data.

  3. Signature of open magnetic field lines in the extended solar corona and of solar wind acceleration

    NASA Technical Reports Server (NTRS)

    Antonucci, E.; Giordano, S.; Benna, C.; Kohl, J. L.; Noci, G.; Michels, J.; Fineschi, S.

    1997-01-01

    The observations carried out with the ultraviolet coronagraph spectrometer onboard the Solar and Heliospheric Observatory (SOHO) are discussed. The purpose of the observations was to determine the line of sight and radial velocity fields in coronal regions with different magnetic topology. The results showed that the regions where the high speed solar wind flows along open field lines are characterized by O VI 1032 and HI Lyman alpha 1216 lines. The global coronal maps of the line of sight velocity were reconstructed. The corona height, where the solar wind reaches 100 km/s, was determined.

  4. In-line particle field holography at Pegasus

    SciTech Connect

    Sorenson, D.S.; Obst, A.; King, N.S.P.

    1995-09-01

    An in-line holographic imaging system has been developed for hydrodynamic experiments at the Pegasus facility located at Los Alamos National Laboratory. Holography offers the unique capability to record distributions of particles over a three dimensional volume. The system to be discussed is used to measure particle distributions of ejecta emitted after a cylindrical aluminum liner (5.0 cm in diameter, 2.0 cm high) impacts a target (3.0 cm in diameter). The ejecta emerges from the target traveling up to 7mm/{micro}s and moves toward the axial center of the system where the holographic imaging is performed. In-line holography is particularly suited for the Pegasus pulsed power facility where the geometry restrictions make off axis holography impractical. In order to record the fast moving particles a frequency-doubled Nd:-YAG laser system has been implemented which produces a 80 ps 20 millijoule pulse at 532 nm. An optical relay system composed of a Fourier optical lens pair has been developed which is placed 4.0 cm from the center of the region of interest. This relay lens pair forms an intermediate image 32 cm from the object plane and the hologram is placed 4cm downstream of the intermediate image. The holographic system and resolution capability are discussed.

  5. Promoter methylation patterns of ABCB1, ABCC1 and ABCG2 in human cancer cell lines, multidrug-resistant cell models and tumor, tumor-adjacent and tumor-distant tissues from breast cancer patients

    PubMed Central

    Spitzwieser, Melanie; Pirker, Christine; Koblmüller, Bettina; Pfeiler, Georg; Hacker, Stefan; Berger, Walter; Heffeter, Petra; Cichna-Markl, Margit

    2016-01-01

    Overexpression of ABCB1, ABCC1 and ABCG2 in tumor tissues is considered a major cause of limited efficacy of anticancer drugs. Gene expression of ABC transporters is regulated by multiple mechanisms, including changes in the DNA methylation status. Most of the studies published so far only report promoter methylation levels for either ABCB1 or ABCG2, and data on the methylation status for ABCC1 are scarce. Thus, we determined the promoter methylation patterns of ABCB1, ABCC1 and ABCG2 in 19 human cancer cell lines. In order to contribute to the elucidation of the role of DNA methylation changes in acquisition of a multidrug resistant (MDR) phenotype, we also analyzed the promoter methylation patterns in drug-resistant sublines of the cancer cell lines GLC-4, SW1573, KB-3-1 and HL-60. In addition, we investigated if aberrant promoter methylation levels of ABCB1, ABCC1 and ABCG2 occur in tumor and tumor-surrounding tissues from breast cancer patients. Our data indicates that hypomethylation of the ABCC1 promoter is not cancer type-specific but occurs in cancer cell lines of different origins. Promoter methylation was found to be an important mechanism in gene regulation of ABCB1 in parental cancer cell lines and their drug-resistant sublines. Overexpression of ABCC1 in MDR cell models turned out to be mediated by gene amplification, not by changes in the promoter methylation status of ABCC1. In contrast to the promoters of ABCC1 and ABCG2, the promoter of ABCB1 was significantly higher methylated in tumor tissues than in tumor-adjacent and tumor-distant tissues from breast cancer patients. PMID:27689338

  6. Sound fields in a lined annular flow duct with lined radial splitters

    NASA Technical Reports Server (NTRS)

    Mungur, P.; Kapur, A.

    1974-01-01

    High attenuation in the inlet duct of fan-jet engines is limited mainly because of two factors: the duct length is short and the frequency is high giving rise to a large duct width to wavelength ratio. Lined radial splitters may be installed. In this configuration not only is the absorbing surface area increased, the acoustic propagation properties in each of the segmented ducts are different to those in a cylindrical or annular duct without radial splitters. Such differences in properties can be used to advantage for mismatching the acoustic source. A lower order spinning mode must propagate as a higher order (integral or fractional) spinning mode. Cut-off phenomena may also be used to advantage. A theoretical modal analysis is made of the sound inside one segment of the annular duct with lined radial splitters.

  7. Diffusion and stochastic island generation in the magnetic field line random walk

    SciTech Connect

    Vlad, M.; Spineanu, F.

    2014-08-10

    The cross-field diffusion of field lines in stochastic magnetic fields described by the 2D+slab model is studied using a semi-analytic statistical approach, the decorrelation trajectory method. We show that field line trapping and the associated stochastic magnetic islands strongly influence the diffusion coefficients, leading to dependences on the parameters that are different from the quasilinear and Bohm regimes. A strong amplification of the diffusion is produced by a small slab field in the presence of trapping. The diffusion regimes are determined and the corresponding physical processes are identified.

  8. Observations of the Ion Signatures of Double Merging and the Formation of Newly Closed Field Lines

    NASA Technical Reports Server (NTRS)

    Chandler, Michael O.; Avanov, Levon A.; Craven, Paul D.

    2007-01-01

    Observations from the Polar spacecraft, taken during a period of northward interplanetary magnetic field (IMF) show magnetosheath ions within the magnetosphere with velocity distributions resulting from multiple merging sites along the same field line. The observations from the TIDE instrument show two separate ion energy-time dispersions that are attributed to two widely separated (-20Re) merging sites. Estimates of the initial merging times show that they occurred nearly simultaneously (within 5 minutes.) Along with these populations, cold, ionospheric ions were observed counterstreaming along the field lines. The presence of such ions is evidence that these field lines are connected to the ionosphere on both ends. These results are consistent with the hypothesis that double merging can produce closed field lines populated by solar wind plasma. While the merging sites cannot be unambiguously located, the observations and analyses favor one site poleward of the northern cusp and a second site at low latitudes.

  9. Field line and Particle orbit Analysis in the Periphery of the Large Helical Device

    NASA Astrophysics Data System (ADS)

    Matsumoto, Yutaka; Oikawa, Shun-ichi; Watanabe, Tsuguhiro

    2002-07-01

    Magnetic field lines and particle orbits were analyzed in the periphery of the Large Helical Device (LHD), which is called the chaotic field line region in this paper. The widths of the chaotic field line region were numerically identified for the standard LHD configuration with the magnetic axis position Rax = 3.75 m and for an improved confinement configuration with Rax = 3.6 m. It was found that the reflected particles include of what we have named chaotic particles and non-chaotic particles. Most of the reflected particles are mirror-confined with strong adiabaticity in the chaotic field line region. The remaining reflected particles, named type-A and type-B particles, are harmful to confinement. We found by detailed analysis of the vacuum magnetic field in the LHD that there exist loss canals that are the open intersections of |\\mbi{B}| = const. and \\mbi{B} \\cdot \

  10. Electric Power High-Voltage Transmission Lines: Design Options, Cost, and Electric and Magnetic Field Levels

    SciTech Connect

    Stoffel, J. B.; Pentecost, E. D.; Roman, R. D.; Traczyk, P. A.

    1994-11-01

    The aim of this report is to provide background information about (1) the electric and magnetic fields (EMFs) of high-voltage transmission lines at typical voltages and line configurations and (2) typical transmission line costs to assist preparers and reviewers of the section on alternatives in environmental documents. This report will give the reviewing individual a better appreciation of the factors affecting EMF strengths near high-voltage transmission lines and the approaches that might be used to reduce EMF impacts on humans and other biological species in the vicinity of high-voltage overhead or underground alternating-current (ac) or direct-current (dc) transmission lines.

  11. Hydrotest measurement system for gas lines gets field trials

    SciTech Connect

    Hodges, A.H. )

    1989-08-07

    Texas Gas Transmission Co., Owensboro, Ky., has developed a tool for recording and documenting the performance of hydrostatic testing. Texas Gas conducted field tests during the summer of 1988 and has continued those tests this year. The hydrostatic-test measurement system (HTMS) is designed to be more compact and easier to use than existing systems. With a Tandy 200 portable lap-top computer, software developed in-house, and other company-fabricated interface hardware, the portable data-acquisition system will measure and record field hydrostatic-test data. After the test, the computer will generate a stress-strain plot (pressure-vs.-gallon count) with a graphics plotter and print the test data.

  12. Potential Structures and Particle Acceleration on Auroral Field Lines.

    DTIC Science & Technology

    2014-09-26

    heated ions at low altitude has been noted, and a causal relationship between downward electric fields and ion conics is suggested., IucUmNT...Transversely Heated Ion Distributions (Ion Conics ) Observed by the S3-3 Satellite Within and Above the Heating Altitude ....... 0........0..........0...with Ion Conics . ........ , ...... .............. . . . .. . . . . .... 22 9. A Plot of Computed Ion Trajectories in v and Altitude (h) with a Heating

  13. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  14. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  15. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  16. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  17. 33 CFR 80.1395 - Puget Sound and adjacent waters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Puget Sound and adjacent waters... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Thirteenth District § 80.1395 Puget Sound and adjacent waters. The 72 COLREGS shall apply on all waters of Puget Sound and adjacent waters, including Lake...

  18. Anomalous diffusion of field lines and charged particles in Arnold-Beltrami-Childress force-free magnetic fields

    SciTech Connect

    Ram, Abhay K.; Dasgupta, Brahmananda; Krishnamurthy, V.; Mitra, Dhrubaditya

    2014-07-15

    The cosmic magnetic fields in regions of low plasma pressure and large currents, such as in interstellar space and gaseous nebulae, are force-free in the sense that the Lorentz force vanishes. The three-dimensional Arnold-Beltrami-Childress (ABC) field is an example of a force-free, helical magnetic field. In fluid dynamics, ABC flows are steady state solutions of the Euler equation. The ABC magnetic field lines exhibit a complex and varied structure that is a mix of regular and chaotic trajectories in phase space. The characteristic features of field line trajectories are illustrated through the phase space distribution of finite-distance and asymptotic-distance Lyapunov exponents. In regions of chaotic trajectories, an ensemble-averaged variance of the distance between field lines reveals anomalous diffusion—in fact, superdiffusion—of the field lines. The motion of charged particles in the force-free ABC magnetic fields is different from the flow of passive scalars in ABC flows. The particles do not necessarily follow the field lines and display a variety of dynamical behavior depending on their energy, and their initial pitch-angle. There is an overlap, in space, of the regions in which the field lines and the particle orbits are chaotic. The time evolution of an ensemble of particles, in such regions, can be divided into three categories. For short times, the motion of the particles is essentially ballistic; the ensemble-averaged, mean square displacement is approximately proportional to t{sup 2}, where t is the time of evolution. The intermediate time region is defined by a decay of the velocity autocorrelation function—this being a measure of the time after which the collective dynamics is independent of the initial conditions. For longer times, the particles undergo superdiffusion—the mean square displacement is proportional to t{sup α}, where α > 1, and is weakly dependent on the energy of the particles. These super-diffusive characteristics

  19. Field Line Resonance at Mercury's Magnetosphere: A Simulation Study

    SciTech Connect

    Eun-Hwa Kim, Jay R. Johnson, and Dong-Hun Lee

    2008-05-22

    Ultra low frequency (ULF) waves, which are assumed to be standing waves on the field, are observed by the Mariner 10 spacecraft at Mercury. These waves are oscillating at 38% of the proton gyrofrequency. It is well known that the heavy ions, such as Na+, are abundant in Mercury's magnetosphere. Because the presence of different ion species has an influence on the plasma dispersion characteristics near the ion gyro-frequencies, such relatively high frequencies of magnetospheric eigenoscillations at Mercury require a multi-fluid treatment for the plasma. Thus ULF waves at Mercury may have a distinct difference from typical ULF oscillations at Earth, which are often described in terms of magnetohydrodynamics (MHD). By adopting a multi-fluid numerical wave model, we examine how magnetic eigenoscillations occur in Mercury's magnetosphere. Because protons and sodium ions are the main constituents at Mercury, we assume an electron-proton- sodium plasma in our model. The frequency spectra and time histories of the electromagnetic fields at the ion-ion hybrid (IIH) and cavity resonances are presented. Our results show: (1) The observed ULF waves are likely compressional waves rather than FLR. (2) Resonant absorption occurs at the IIH resonance, thus incoming compressional waves are converted into the IIH resonance. (3) The IIH resonance is strongly guided by the background magnetic field and shows linear polarization in the east-west meridian. (4) Both the Alfvén and the IIH are suggested as a mechanism for FLR at Mercury. (5) The resonance frequency enables us to estimate the local heavy ion concentration ratio.

  20. Solar magnetic field studies using the 12 micron emission lines. II - Stokes profiles and vector field samples in sunspots

    NASA Technical Reports Server (NTRS)

    Hewagama, Tilak; Deming, Drake; Jennings, Donald E.; Osherovich, Vladimir; Wiedemann, Gunter; Zipoy, David; Mickey, Donald L.; Garcia, Howard

    1993-01-01

    Polarimetric observations at 12 microns of two sunpots are reported. The horizontal distribution of parameters such as magnetic field strength, inclination, azimuth, and magnetic field filling factors are presented along with information about the height dependence of the magnetic field strength. Comparisons with contemporary magnetostatic sunspot models are made. The magnetic data are used to estimate the height of 12 micron line formation. From the data, it is concluded that within a stable sunspot there are no regions that are magnetically filamentary, in the sense of containing both strong-field and field-free regions.

  1. A method for measuring magnetic fields in sunspots using Zeeman-broadened absorption lines

    NASA Astrophysics Data System (ADS)

    Oostra, Benjamin

    2017-04-01

    We present measurements of magnetic fields in several sunspots using high-resolution spectra obtained with the ESPARTACO spectrograph at the Universidad de los Andes, with the aim to explore experimental possibilities for students. Because the Zeeman line splitting is smaller than the line width, our work only observes broadened absorption lines. This broadening, however, can be measured and suitably modeled, giving realistic quantitative results.

  2. The Effects of a History-Based Instructional Material on the Students' Understanding of Field Lines

    ERIC Educational Resources Information Center

    Pocovi, M. Cecilia

    2007-01-01

    Many students in physics courses fail to achieve a desired conceptual change because they assign an incorrect ontology to the to-be-learned concept. This situation has been detected in previous research for the case of field lines: many college students assign material properties to the lines and describe them, for example, as tubes that contain…

  3. Corona and field effects experience on an operating utility six-phase transmission line

    SciTech Connect

    Stewart, J.R.; Oppel, L.J.; Richeda, R.J.

    1998-10-01

    A three-year operating period of a six-phase power transmission line to an operating utility has given experimental verification to available methods for calculation of electric and magnetic fields, radio noise, and audible noise from six-phase overhead lines. Successful completion of the operational measurement program has provided further encouragement to the future application of high phase order.

  4. Field evaluation of mint mutant and hybrid lines for resistance to Verticillium wilt and yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Severity of Verticillium wilt varied significantly among mint lines and cultivars in the inoculated and non-inoculated sub-plots in two field trials. Verticillium wilt was significantly less severe for mutant lines 87M0109-1, 84M0107-7, and M90-11 than for Black Mitcham in 2002 and 2003. Verticilli...

  5. Biological effects of power line fields: New York State Power Lines Project Scientific Advisory Panel: Final report

    SciTech Connect

    Ahlbom, A.; Albert, E.N.; Fraser-Smith, A.C.; Grodzinsky, A.J.; Marron, M.T.; Martin, A.O.; Persinger, M.A.; Shelanski, M.L.; Wolpow, E.R.

    1987-07-01

    The New York State Power Lines Project was established to conduct research and to review the scientific literature to determine whether health hazards of electric and magnetic fields are possible. Particular attention was directed to the fields generated by 765-kV overhead transmission lines. The research program provided support to 16 research groups studying human, animal and isolated cell sensitivity to electric and magnetic fields. No effects were found on reproduction, growth or development. Several studies showed no evidence of genetic or chromosomal damage that might lead to inherited effects or cause cancer. While most measurements of behavior and brain function did not demonstrate changes, some did show changes that were small but consistent. Some of these appear to result from changes in body rhythms, and might interfere with normal sleep patterns. There were also changes in pain responses and in the ability of rats to learn. A more serious concern comes from a study of cancer in children suggesting that children with leukemia and brain cancer are more likely to live in homes where there are elevated 60-Hz magnetic field levels. Although much more research is needed before the question whether the magnetic fields actually cause or promote cancer can be resolved, the basis for such an hypothesis is now established. 159 refs., 12 figs., 7 tabs.

  6. Evolution of the Magnetic Field Line Diffusion Coefficient and Non-Gaussian Statistics

    NASA Astrophysics Data System (ADS)

    Snodin, A. P.; Ruffolo, D.; Matthaeus, W. H.

    2016-08-01

    The magnetic field line random walk (FLRW) plays an important role in the transport of energy and particles in turbulent plasmas. For magnetic fluctuations that are transverse or almost transverse to a large-scale mean magnetic field, theories describing the FLRW usually predict asymptotic diffusion of magnetic field lines perpendicular to the mean field. Such theories often depend on the assumption that one can relate the Lagrangian and Eulerian statistics of the magnetic field via Corrsin’s hypothesis, and additionally take the distribution of magnetic field line displacements to be Gaussian. Here we take an ordinary differential equation (ODE) model with these underlying assumptions and test how well it describes the evolution of the magnetic field line diffusion coefficient in 2D+slab magnetic turbulence, by comparisons to computer simulations that do not involve such assumptions. In addition, we directly test the accuracy of the Corrsin approximation to the Lagrangian correlation. Over much of the studied parameter space we find that the ODE model is in fairly good agreement with computer simulations, in terms of both the evolution and asymptotic values of the diffusion coefficient. When there is poor agreement, we show that this can be largely attributed to the failure of Corrsin’s hypothesis rather than the assumption of Gaussian statistics of field line displacements. The degree of non-Gaussianity, which we measure in terms of the kurtosis, appears to be an indicator of how well Corrsin’s approximation works.

  7. Modification of atmospheric DC fields by space charge from high-voltage power lines

    NASA Astrophysics Data System (ADS)

    Fews, A. P.; Wilding, R. J.; Keitch, P. A.; Holden, N. K.; Henshaw, D. L.

    Corona ion discharge is responsible for a flux of small ions emanating from an overhead power line capable of modifying the ambient electrical environment. The ensuing space charge can be detected as a change in magnitude of the earth's natural DC electric field at ground level. DC field mill meters were used to measure the vertical component of electric fields upwind and downwind of 132 and 400 kV power lines. Evidence of space charge blowing downwind of power lines was observed in 21 out of 22 cases. Time series measurements recorded in the downwind direction were highly variable with fields of higher magnitude compared to those recorded upwind. Model DC field profiles were used to estimate a lower limit to the space charge density at body height arising from power lines. The average lower limit was ˜3000 cm -3 excess unipolar charges. The result suggests that between 10% and 60% of outdoor aerosols gain excess charge by the attachment of corona ions. Downwind of a 400 kV line in Somerset that was prone to excessive corona discharge, the estimated mean lower limit excess unipolar space charge density was ˜6000 cm -3, suggesting that up to 100% of aerosols gain excess charge by the attachment of corona ions. Investigations into the time variation of DC electric fields around motorways and the natural diurnal variation of the earth's DC field were also undertaken and compared to the power line data. The results show that the power line time series are clearly distinguishable from typical examples of both types of field variation, demonstrating the relatively highly charged atmospheres that generally exist around high-voltage power lines. The results are of potential public health concern, because they suggest a degree of aerosol charging that may result in a non-trivial increase in lung deposition of inhaled pollutant aerosols.

  8. Experimental studies on ion acceleration and stream line detachment in a diverging magnetic field

    PubMed Central

    Terasaka, K.; Yoshimura, S.; Ogiwara, K.; Aramaki, M.; Tanaka, M. Y.

    2010-01-01

    The flow structure of ions in a diverging magnetic field has been experimentally studied in an electron cyclotron resonance plasma. The flow velocity field of ions has been measured with directional Langmuir probes calibrated with the laser induced fluorescence spectroscopy. For low ion-temperature plasmas, it is concluded that the ion acceleration due to the axial electric field is important compared with that of gas dynamic effect. It has also been found that the detachment of ion stream line from the magnetic field line takes place when the parameter |fciLB∕Vi| becomes order unity, where fci, LB, and Vi are the ion cyclotron frequency, the characteristic scale length of magnetic field inhomogeneity, and the ion flow velocity, respectively. In the detachment region, a radial electric field is generated in the plasma and the ions move straight with the E×B rotation driven by the radial electric field. PMID:20838424

  9. Transition from drift to interchange instabilities in an open magnetic field line configuration

    SciTech Connect

    Poli, F. M.; Ricci, P.; Fasoli, A.; Podesta, M.

    2008-03-15

    The transition from a regime dominated by drift instabilities to a regime dominated by pure interchange instabilities is investigated and characterized in the simple magnetized toroidal device TORPEX [TORoidal Plasma EXperiment, A. Fasoli et al., Phys. of Plasmas 13, 055906 (2006)]. The magnetic field lines are helical, with a dominant toroidal component and a smaller vertical component. Instabilities with a drift character are observed in the favorable curvature region, on the high field side with respect to the maximum of the background density profile. For a limited range of values of the vertical field they coexist with interchange instabilities in the unfavorable curvature region, on the plasma low field side. With increasing vertical magnetic field magnitude, a gradual transition between the two regimes is observed on the low field side, controlled by the value of the field line connection length. The observed transition follows the predictions of a two-fluid linear model.

  10. FLiT: a field line trace code for magnetic confinement devices

    NASA Astrophysics Data System (ADS)

    Innocente, P.; Lorenzini, R.; Terranova, D.; Zanca, P.

    2017-04-01

    This paper presents a field line tracing code (FLiT) developed to study particle and energy transport as well as other phenomena related to magnetic topology in reversed-field pinch (RFP) and tokamak experiments. The code computes magnetic field lines in toroidal geometry using curvilinear coordinates (r, ϑ, ϕ) and calculates the intersections of these field lines with specified planes. The code also computes the magnetic and thermal diffusivity due to stochastic magnetic field in the collisionless limit. Compared to Hamiltonian codes, there are no constraints on the magnetic field functional formulation, which allows the integration of whichever magnetic field is required. The code uses the magnetic field computed by solving the zeroth-order axisymmetric equilibrium and the Newcomb equation for the first-order helical perturbation matching the edge magnetic field measurements in toroidal geometry. Two algorithms are developed to integrate the field lines: one is a dedicated implementation of a first-order semi-implicit volume-preserving integration method, and the other is based on the Adams–Moulton predictor–corrector method. As expected, the volume-preserving algorithm is accurate in conserving divergence, but slow because the low integration order requires small amplitude steps. The second algorithm proves to be quite fast and it is able to integrate the field lines in many partially and fully stochastic configurations accurately. The code has already been used to study the core and edge magnetic topology of the RFX-mod device in both the reversed-field pinch and tokamak magnetic configurations.

  11. Field Line Resonances in Quiet and Disturbed Time Three-dimensional Magnetospheres

    SciTech Connect

    C.Z. Cheng; S. Zaharia

    2002-05-30

    Numerical solutions for field line resonances (FLR) in the magnetosphere are presented for three-dimensional equilibrium magnetic fields represented by two Euler potentials as B = -j Y -a, where j is the poloidal flux and a is a toroidal angle-like variable. The linearized ideal-MHD equations for FLR harmonics of shear Alfvin waves and slow magnetosonic modes are solved for plasmas with the pressure assumed to be isotropic and constant along a field line. The coupling between the shear Alfvin waves and the slow magnetosonic waves is via the combined effects of geodesic magnetic field curvature and plasma pressure. Numerical solutions of the FLR equations are obtained for a quiet time magnetosphere as well as a disturbed time magnetosphere with a thin current sheet in the near-Earth region. The FLR frequency spectra in the equatorial plane as well as in the auroral latitude are presented. The field line length, magnetic field intensity, plasma beta, geodesic curvature and pressure gradient in the poloidal flux surface are important in determining the FLR frequencies. In general, the computed shear Alfvin FLR frequency based on the full MHD model is larger than that based on the commonly adopted cold plasma model in the beq > 1 region. For the quiet time magnetosphere, the shear Alfvin resonance frequency decreases monotonically with the equatorial field line distance, which reasonably explains the harmonically structured continuous spectrum of the azimuthal magnetic field oscillations as a function of L shell in the L is less than or equal to 9RE region. However, the FLR frequency spectrum for the disturbed time magnetosphere with a near-Earth thin current sheet is substantially different from that for the quiet time magnetosphere for R > 6RE, mainly due to shorter field line length due to magnetic field compression by solar wind, reduced magnetic field intensity in the high-beta current sheet region, azimuthal pressure gradient, and geodesic magnetic field

  12. New Argentine Central-West line taps rich Neuquen gas field

    SciTech Connect

    Watts, J.

    1982-02-01

    Argentina's new Central-West gas pipeline consists of 697 miles of 30-in. line and 451 miles of smaller gathering and distribution lines that link the rich Neuquen gas field with cities to the north. A financing package drawn up by 21 banks in the US and Europe allowed Cogasco S.A. to build the line for Gas del Estado across the roadless pampas east of the Andes. Primarily an agricultural country, Argentina had to import all the equipment and materials for the project. Site work began in July, 1980 with 800 workers employed on three spreads; the line was commissioned in November, 1981, 15 months ahead of the contract schedule.

  13. Some Considerations about Inferring Coronal Magnetic Fields and Other Coronal Properties from Coronal Emission Line Polarization

    NASA Astrophysics Data System (ADS)

    Arnaud, J.; Habbal, S. R.; Arndt, M.; Woo, R.

    2003-12-01

    Ground based studies of Coronal Emission Lines (CEL) linear polarization had been carried out for the 530.3 nm FeXIV line at Pic du Midi and for the 1074.7 nm Fe XIII line at Sac Peak in the 1977-1980 period. The large scale organization of the polarization has clearly revealed the existence of a large scale structure of the coronal magnetic field. More recently, the first successful eclipse CEL polarimetric measurements were made in the 1074.7 nm line during the total solar eclipse of 21 June 2001, confirming earlier results of the predominance of a radial direction of the coronal magnetic field. A first measurement of the circular polarization in the 1074.7 nm line has also recently been performed. Circular polarization gives access to the strength of the LOS magnetic field while the linear polarization maps the transverse magnetic field direction. We will use ground based and eclipse 1074.7 nm line polarimetric data to provide examples of the properties (e.g., magnetic field, abundances, inhomogeneities) such observations can help to infer in this 3-D and optically thin medium.

  14. Current singularities in line-tied three-dimensional magnetic fields

    SciTech Connect

    Craig, I. J. D.; Pontin, D. I. E-mail: dpontin@maths.dundee.ac.uk

    2014-06-20

    This paper considers the current distributions that derive from finite amplitude perturbations of line-tied magnetic fields comprising hyperbolic field structures. The initial equilibrium on which we principally focus is a planar magnetic X-point threaded by a uniform axial field. This field is line-tied on all surfaces but subject to three-dimensional (3D) disturbances that alter the initial topology. Results of ideal relaxation simulations are presented which illustrate how intense current structures form that can be related, through the influence of line-tying, to the quasi-separatrix layers (QSLs) of the initial configuration. It is demonstrated that the location within the QSL that attracts the current, and its scaling properties, are strongly dependent on the relative dimensions of the QSL with respect to the line-tied boundaries. These results are contrasted with the behavior of a line-tied 3D field containing an isolated null point. In this case, it is found that the dominant current always forms at the null, but that the collapse is inhibited when the null is closer to a line-tied boundary.

  15. Current Singularities in Line-tied Three-dimensional Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Craig, I. J. D.; Pontin, D. I.

    2014-06-01

    This paper considers the current distributions that derive from finite amplitude perturbations of line-tied magnetic fields comprising hyperbolic field structures. The initial equilibrium on which we principally focus is a planar magnetic X-point threaded by a uniform axial field. This field is line-tied on all surfaces but subject to three-dimensional (3D) disturbances that alter the initial topology. Results of ideal relaxation simulations are presented which illustrate how intense current structures form that can be related, through the influence of line-tying, to the quasi-separatrix layers (QSLs) of the initial configuration. It is demonstrated that the location within the QSL that attracts the current, and its scaling properties, are strongly dependent on the relative dimensions of the QSL with respect to the line-tied boundaries. These results are contrasted with the behavior of a line-tied 3D field containing an isolated null point. In this case, it is found that the dominant current always forms at the null, but that the collapse is inhibited when the null is closer to a line-tied boundary.

  16. A region of intense plasma wave turbulence on auroral field lines

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Frank, L. A.

    1976-01-01

    This report presents a detailed study of the plasma wave turbulence observed by HAWKEYE-1 and IMP-6 on high latitude auroral field lines and investigates the relationship of this turbulence to magnetic field and plasma measurements obtained in the same region.

  17. Magnetic Field Line Topology of the Scrape-Off Layer in the Compact Stellarator NCSX

    NASA Astrophysics Data System (ADS)

    Grossman, Arthur; Mioduszewski, Peter; Fenstermacher, Max; Koniges, Alice; Rognlien, Tom

    2001-10-01

    The magnetic topology of the plasma boundary of the proposed compact stellarator NCSX is investigated using the MFBE[1] and VMEC2000[2] codes. The VMEC code provides a free boundary equilibrium and the magnetics from external coils and bootstrap plasma currents inside the last closed magnetic surface (LCMS). The MFBE code uses these results to calculate the magnetic fields of these finite beta equilibria outside the LCMS in a form suitable for line tracing. The Poincaré plots of field lines started outside the LCMS indicate preservation of initial radial ordering of field lines up to intersections with vacuum vessel and plasma facing components. A large flux expansion of field lines is observed between the midplane and tips of the banana shaped cross-section, due to the presence of a nearby poloidal field null used to create the banana shape. TRIM coils used to heal islands just within the LCMS appear to reduce stochasticity just outside the LCMS as well as enhance an island structure outside the LCMS. Field lines are observed to move in and out radially as they are followed toroidally. Power and particle control design based on these observations include the limiting structure geometry and baffles designed to intersect islands outside the LCMS. [1] E.Strumberger, Nuclear Fusion 37 1997 19. [2] S.Hirshman, Comp. Phys. Commun. 43 1986 143.

  18. Magnetic field measurements and wind-line variability of OB-type stars

    NASA Astrophysics Data System (ADS)

    Schnerr, R. S.; Henrichs, H. F.; Neiner, C.; Verdugo, E.; de Jong, J.; Geers, V. C.; Wiersema, K.; van Dalen, B.; Tijani, A.; Plaggenborg, B.; Rygl, K. L. J.

    2008-06-01

    Context: The first magnetic fields in O- and B-type stars that do not belong to the Bp-star class, have been discovered. The cyclic UV wind-line variability, which has been observed in a significant fraction of early-type stars, is likely to be related to such magnetic fields. Aims: We attempt to improve our understanding of massive-star magnetic fields, and observe twenty-five carefully-selected, OB-type stars. Methods: Of these stars we obtain 136 magnetic field strength measurements. We present the UV wind-line variability of all selected targets and summarise spectropolarimetric observations acquired using the MUSICOS spectropolarimeter, mounted at the TBL, Pic du Midi, between December 1998 and November 2004. From the average Stokes I and V line profiles, derived using the LSD method, we measure the magnetic field strengths, radial velocities, and first moment of the line profiles. Results: No significant magnetic field is detected in any OB-type star that we observed. Typical 1σ errors are between 15 and 200 G. A possible magnetic-field detection for the O9V star 10 Lac remains uncertain, because the field measurements depend critically on the fringe-effect correction in the Stokes V spectra. We find excess emission in UV-wind lines, centred about the rest wavelength, to be a new indirect indicator of the presence of a magnetic field in early B-type stars. The most promising candidates to host magnetic fields are the B-type stars δ Cet and 6 Cep, and a number of O stars. Conclusions: Although some O and B stars have strong dipolar field, which cause periodic variability in the UV wind-lines, such strong fields are not widespread. If the variability observed in the UV wind-lines of OB stars is generally caused by surface magnetic fields, these fields are either weak (⪉few hundred G) or localised. Figures [see full textsee full textsee full textsee full textsee full textsee full text]-[see full textsee full textsee full textsee full textsee full textsee

  19. Bounds on the length of magnetic field lines in a two-dimensional plasma.

    PubMed

    Núñez, M

    2001-03-01

    Magnetic field lines in ideal turbulent plasmas tend to become quite complicated and their length to grow in time. Diffusivity allows for reconnection and possible shortening, but this fact has not so far been rigorously quantified. We show that in a two-dimensional diffusive plasma the mean length of field lines stays bounded for all time. Moreover, these estimates are local, in the sense that the mean values of magnetic field and velocity in the neighborhood of a ball determine bounds for length within the ball, without recourse to external magnitudes.

  20. Determination of magnetic fields in broad line region of active galactic nuclei from polarimetric observations

    NASA Astrophysics Data System (ADS)

    Piotrovich, Mikhail; Silant'ev, Nikolai; Gnedin, Yuri; Natsvlishvili, Tinatin; Buliga, Stanislava

    2017-02-01

    Magnetic fields play an important role in confining gas clouds in the broad line region (BLR) of active galactic nuclei (AGN) and in maintaining the stability of these clouds. Without magnetic fields the clouds would not be stable, and soon after their formation they would expand and disperse. We show that the strength of the magnetic field can be derived from the polarimetric observations. Estimates of magnetic fields for a number of AGNs are based on the observed polarization degrees of broad Hα lines and nearby continuum. The difference between their values allows us to estimate the magnetic field strength in the BLR using the method developed by Silant'ev et al. (2013). Values of magnetic fields in BLR for a number of AGNs have been derived.

  1. Three-dimensional photogrammetric measurement of magnetic field lines in the WEGA stellarator.

    PubMed

    Drewelow, Peter; Bräuer, Torsten; Otte, Matthias; Wagner, Friedrich; Werner, Andreas

    2009-12-01

    The magnetic confinement of plasmas in fusion experiments can significantly degrade due to perturbations of the magnetic field. A precise analysis of the magnetic field in a stellarator-type experiment utilizes electrons as test particles following the magnetic field line. The usual fluorescent detector for this electron beam limits the provided information to two-dimensional cut views at certain toroidal positions. However, the technique described in this article allows measuring the three-dimensional structure of the magnetic field by means of close-range photogrammetry. After testing and optimizing the main diagnostic components, measurements of the magnetic field lines were accomplished with a spatial resolution of 5 mm. The results agree with numeric calculations, qualifying this technique as an additional tool to investigate magnetic field configurations in a stellarator. For a possible future application, ways are indicated on how to reduce experimental error sources.

  2. Theory of magnetic field line random walk in noisy reduced magnetohydrodynamic turbulence

    SciTech Connect

    Ruffolo, D.; Matthaeus, W. H.

    2013-01-15

    When a magnetic field consists of a mean part and fluctuations, the stochastic wandering of its field lines is often treated as a diffusive process. Under suitable conditions, a stable value is found for the mean square transverse displacement per unit parallel displacement relative to the mean field. Here, we compute the associated field line diffusion coefficient for a highly anisotropic 'noisy' reduced magnetohydrodynamic model of the magnetic field, which is useful in describing low frequency turbulence in the presence of a strong applied DC mean magnetic field, as may be found, for example, in the solar corona, or in certain laboratory devices. Our approach is nonperturbative, based on Corrsin's independence hypothesis, and makes use of recent advances in understanding factors that control decorrelation over a range of parameters described by the Kubo number. Both Bohm and quasilinear regimes are identified.

  3. New 0.54 aperture i-line wafer stepper with field-by-field leveling combined with global alignment

    NASA Astrophysics Data System (ADS)

    van den Brink, Martin A.; Katz, Barton A.; Wittekoek, Stefan

    1991-07-01

    i-line wafer steppers are evolving as established production tools, and it is evident that they will be used to realize features in the sub-half-micron region. Consequently, i-line steppers can be expected to be the equipment of choice for volume production of 16 MBit DRAMs and possibly the first generation of 64 Mbit devices, before the introduction of DUV lithography. However, for this sub-half-micron resolution, lenses with higher apertures and large field sizes will be required. In this paper a new family of wafer steppers is introduced, with a new mechanical frame design and modular architecture which can accommodate a family of large field i-line and deep UV lenses. Results from the first lens type with NAequals0.54 and a field diameter of 25.5 mm are described. To overcome the anticipated depth of focus problems on production wafers, a field-by-field leveling system is introduced, ensuring optimum focus over the whole image field. A challenging problem of wafer steppers using this option is the alignment accuracy during stepping of stage and active leveling of the wafer chuck. The stepper concept introduced here is able to realize the field-by-field leveling without the need for the throughput consuming field-by-field alignment. For that purpose a wafer stage with a new metrology system and improved accuracy has been designed, resulting in an overlay accuracy better than 85 nm in the global alignment mode. Simultaneously a throughput of more than 80 150 mm wafers per hour is realized. Along with the new lens and metrology concept, the stepper contains local environmental control systems performing better than class 1, to ensure clean handling of 8-inch wafers without the need for space consuming environmental enclosures. This paper reports practical results from the new stepper, including resist features below 0.4 micrometers , overlay measurements, particle control, as well as a general description of the new stepper architecture.

  4. Relation of the green coronal line intensity to sunspot areas and magnetic fields of different scales

    NASA Astrophysics Data System (ADS)

    Badalyan, O. G.; Bludova, N. G.

    2014-07-01

    The intensity of Fe XIV 530.3-nm green coronal line is compared quantitatively with the strength of magnetic fields of small and large scales and also with total sunspot areas for 1977-2001. A degree of similarity of appropriate synoptic maps is evaluated using correlation analysis. The green line intensity maps are constructed from data of its daily monitoring. Strengths of magnetic fields are calculated in a potential approximation using the photosphere observations of Wilcox Solar Observatory for a distance of 1.1 The calculations are performed separately for fields of large and small spatial scales. The total area of sunspots is obtained using data from the Greenwich Catalogue and its continuation by USAF/NOAA. The correlation has been calculated for the aggregate of areas (with a size of 20° in latitude and 30° in longitude) coinciding spatially on all maps. It is found that the most correlation between the green line intensity and coronal fields of small scales is observed in a zone of 0°-20°. The correlation with total sunspot areas (i.e., with local fields at the photosphere level) is substantially less here. In the higher-latitude zone 20°-40°, correlation of the green-line intensity with spot areas and small-scale coronal fields decreases. The large-scale fields have little influence on the green-line emission in the spot-formation zone. These results are the evidence of a complex nature of the effect of different-scale fields, arising as a result of dynamo activity in the subsurface (leptocline) and deep-lying (tachocline) layers of the convective zone, on the processes of the Sun's corona heating and green coronal line emission.

  5. POLARIZED LINE FORMATION IN MOVING ATMOSPHERES WITH PARTIAL FREQUENCY REDISTRIBUTION AND A WEAK MAGNETIC FIELD

    SciTech Connect

    Sampoorna, M.; Nagendra, K. N. E-mail: knn@iiap.res.in

    2015-10-10

    The dynamical state of the solar and stellar atmospheres depends on the macroscopic velocity fields prevailing within them. The presence of such velocity fields in the line formation regions strongly affects the polarized radiation field emerging from these atmospheres. Thus it becomes necessary to solve the radiative transfer equation for polarized lines in moving atmospheres. Solutions based on the “observer’s frame method” are computationally expensive to obtain, especially when partial frequency redistribution (PRD) in line scattering and large-amplitude velocity fields are taken into account. In this paper we present an efficient alternative method of solution, namely, the comoving frame technique, to solve the polarized PRD line formation problems in the presence of velocity fields. We consider one-dimensional planar isothermal atmospheres with vertical velocity fields. We present a study of the effect of velocity fields on the emergent linear polarization profiles formed in optically thick moving atmospheres. We show that the comoving frame method is far superior when compared to the observer’s frame method in terms of the computational speed and memory requirements.

  6. Flexible gas insulated transmission line having regions of reduced electric field

    DOEpatents

    Cookson, Alan H.; Fischer, William H.; Yoon, Kue H.; Meyer, Jeffry R.

    1983-01-01

    A gas insulated transmission line having radially flexible field control means for reducing the electric field along the periphery of the inner conductor at predetermined locations wherein the support insulators are located. The radially flexible field control means of the invention includes several structural variations of the inner conductor, wherein careful controlling of the length to depth of surface depressions produces regions of reduced electric field. Several embodiments of the invention dispose a flexible connector at the predetermined location along the inner conductor where the surface depressions that control the reduced electric field are located.

  7. Lessening the Effects of Projection for Line-of-Sight Magnetic Field Data

    NASA Astrophysics Data System (ADS)

    Leka, K. D.; Barnes, Graham; Wagner, Eric

    2016-05-01

    A method for treating line-of-sight magnetic field data (Blos) is developed for the goal of reconstructing the radially-directed component (Br) of the solar photospheric magnetic field. The latter is generally the desired quantity for use as a boundary for modeling efforts and observational interpretation of the surface field, but the two are only equivalent where the viewing angle is exactly zero (μ=1.0). A common approximation known as the "μ-correction", which assumes all photospheric field to be radial, is compared to a method which invokes a potential field constructed to match the observed Blos (Alissandrakis 1981; Sakurai 1982), from which the potential field radial field component (Brpot) is recovered.We compare this treatment of Blos data to the radial component derived from SDO/HMI full-disk vector magnetograms as the "ground truth", and discuss the implications for data analysis and modeling efforts. In regions that are truly dominated by radial field, the μ-correction performs acceptably if not better than the potential-field approach. However, for any solar structure which includes horizontal fields, i.e. active regions, the potential-field method better recovers magnetic neutral line location and the inferred strength of the radial field.This work was made possible through contracts with NASA, NSF, and NOAA/SBIR.

  8. MAGNETIC FIELD-LINE LENGTHS IN INTERPLANETARY CORONAL MASS EJECTIONS INFERRED FROM ENERGETIC ELECTRON EVENTS

    SciTech Connect

    Kahler, S. W.; Haggerty, D. K.; Richardson, I. G.

    2011-08-01

    About one quarter of the observed interplanetary coronal mass ejections (ICMEs) are characterized by enhanced magnetic fields that smoothly rotate in direction over timescales of about 10-50 hr. These ICMEs have the appearance of magnetic flux ropes and are known as 'magnetic clouds' (MCs). The total lengths of MC field lines can be determined using solar energetic particles of known speeds when the solar release times and the 1 AU onset times of the particles are known. A recent examination of about 30 near-relativistic (NR) electron events in and near 8 MCs showed no obvious indication that the field-line lengths were longest near the MC boundaries and shortest at the MC axes or outside the MCs, contrary to the expectations for a flux rope. Here we use the impulsive beamed NR electron events observed with the Electron Proton and Alpha Monitor instrument on the Advanced Composition Explorer spacecraft and type III radio bursts observed on the Wind spacecraft to determine the field-line lengths inside ICMEs included in the catalog of Richardson and Cane. In particular, we extend this technique to ICMEs that are not MCs and compare the field-line lengths inside MCs and non-MC ICMEs with those in the ambient solar wind outside the ICMEs. No significant differences of field-line lengths are found among MCs, ICMEs, and the ambient solar wind. The estimated number of ICME field-line turns is generally smaller than those deduced for flux-rope model fits to MCs. We also find cases in which the electron injections occur in solar active regions (ARs) distant from the source ARs of the ICMEs, supporting CME models that require extensive coronal magnetic reconnection with surrounding fields. The field-line lengths are found to be statistically longer for the NR electron events classified as ramps and interpreted as shock injections somewhat delayed from the type III bursts. The path lengths of the remaining spike and pulse electron events are compared with model calculations

  9. Magnetic Field-Line Lengths in Interplanetary Coronal Mass Ejections Inferred from Energetic Electron Events

    NASA Technical Reports Server (NTRS)

    Kahler, S. W.; Haggerty, D. K.; Richardson, I. G.

    2011-01-01

    About one quarter of the observed interplanetary coronal mass ejections (ICMEs) are characterized by enhanced magnetic fields that smoothly rotate in direction over timescales of about 10-50 hr. These ICMEs have the appearance of magnetic flux ropes and are known as "magnetic clouds" (MCs). The total lengths of MC field lines can be determined using solar energetic particles of known speeds when the solar release times and the I AU onset times of the particles are known. A recent examination of about 30 near-relativistic (NR) electron events in and near 8 MCs showed no obvious indication that the field-line lengths were longest near the MC boundaries and shortest at the MC axes or outside the MCs, contrary to the expectations for a flux rope. Here we use the impulsive beamed NR electron events observed with the Electron Proton and Alpha Monitor instrument on the Advanced Composition Explorer spacecraft and type III radio bursts observed on the Wind spacecraft to determine the field-line lengths inside ICMEs included in the catalog of Richardson & Cane. In particular, we extend this technique to ICMEs that are not MCs and compare the field-line lengths inside MCs and non-MC ICMEs with those in the ambient solar wind outside the ICMEs. No significant differences of field-line lengths are found among MCs, ICMEs, and the ambient solar wind. The estimated number of ICME field-line turns is generally smaller than those deduced for flux-rope model fits to MCs. We also find cases in which the electron injections occur in solar active regions CARs) distant from the source ARs of the ICMEs, supporting CME models that require extensive coronal magnetic reconnection with surrounding fields. The field-line lengths are found to be statistically longer for the NR electron events classified as ramps and interpreted as shock injections somewhat delayed from the type III bursts. The path lengths of the remaining spike and pulse electron events are compared with model calculations of

  10. Geomagnetic field-line resonant harmonics measured by the Viking and AMPTE/CCE magnetic field experiments

    NASA Technical Reports Server (NTRS)

    Zanetti, L. J.; Potemra, T. A.; Erlandson, R. E.; Engebretson, M. J.; Acuna, M. H.

    1987-01-01

    The first simultaneous observations of multiple harmonic, azimuthally polarized, ULF pulsations at two points along a geomagnetic flux tube in space are reported. In March 1986, the elliptically orbiting equatorial AMPTE/CCE satellite was oriented with the apogee near 0830 h MLT, and the orbital plane of the polar-orbiting Viking satellite was at 1000 MLT. The satellites were situated within approximately the same flux tube but with an effective separation of approximately 10 R(e) near L = 8 on the inbound pass of the AMPTE/CCE orbit. Structured harmonic pulsations were observed by the magnetic field experiments on both spacecraft, and they appeared to turn off and on simultaneously at both locations. Both the observations and the relative amplitudes along the magnetic field lines support recent ideas of multiple field-line resonances of Alfven waves.

  11. Local magnetic fields diagnostics in solar faculae using Fel 5233 line

    NASA Astrophysics Data System (ADS)

    Lozitsky, V.; Osyka, O.; Liakh, V.

    2015-12-01

    The bisectors of I ± V Stokes profiles are analyzed for measurements of local magnetic field strengths in solar faculae of 7 August 2013observed on Echelle spectrograph of horizontal solar telescope of the Astronomical Observatory of Kyiv Taras Shevchenko National University. Obtained observational data indicate the inapplicability the weak-field and one-component approximation for this line. This follows from essential (till five times) differences of bisector splitting in different parts of line profile. A fine effect was found from analysis of mean-square deviation of observed bisector splitting from linear trend. This deviation has a maximum (relatively error level) on distance nearly 120 mǺ from line center that could indicate the presence of local magnetic field of about 7.4 kG.

  12. Local Magnetic Field Diagnostics in Solar Faculae Using FeI 5233 Line

    NASA Astrophysics Data System (ADS)

    Lozitsky, V.; Osyka, O.; Lyakh, V.

    2015-06-01

    The bisectors of I ± V Stokes profiles are analyzed for measurements of local magnetic field strengths in solar faculae of 7 August 2013 observed on Echelle spectrograph of horizontal solar telescope of the Astronomical Observatory of Kyiv Taras Shevchenko National University. Obtained observational data indicate the inapplicability the weak-field and one-component approximation for this line. This follows from essential (till five times) differences of bisector splitting in different parts of line profile. A fine effect was found from analysis of mean-square deviation of observed bisector splitting from linear trend. This deviation has a maximum (relatively error level) on distance nearly 120 mÅ from line center that could indicate the presence of local magnetic field of about 7.4 kG.

  13. New Argentine Central-West Line taps rich Neuquen gas field

    SciTech Connect

    Watts, J.

    1982-02-01

    Argentina's Centro-Oeste (Central-West) Gas Pipeline is now a reality, carrying gas from the extensive Loma de la Lata (Hill of Tin) field in Neuquen State to cities which had been relying on bottled gas. The project is impressive, but hardly seems unique. A pipeline consisting of 697 miles of 30-in. line and 451 miles of smaller diameter gathering and distribution lines is a big project but nothing that has not been done before. Sometimes figures and statistics hide more than they reveal. A discussion is provided of project financing, logistics, pipeline outlets, treatment plants, route, construction, other lines, compressor stations, and suppliers.

  14. The Latitudinal Excursion of Coronal Magnetic Field Lines in Response to Differential Rotation: MHD Simulations

    NASA Technical Reports Server (NTRS)

    Lionello, Roberto; Linker, Jon A.; Mikic, Zoran; Riley, Pete

    2006-01-01

    Solar energetic particles, which are believed to originate from corotating interacting regions (CIRS) at low heliographic latitude, were observed by the Ulysses spacecraft even as it passed over the Sun's poles. One interpretation of this result is that high-latitude field lines intercepted by Ulysses connect to low-latitude CIRs at much larger heliocentric distances. The Fisk model explains the latitudinal excursion of magnetic field lines in the solar corona and heliosphere as the inevitable consequence of the interaction of a tilted dipole in a differentially rotating photosphere with rigidly rotating coronal holes. We use a time-dependent three-dimensional magnetohydrodynamic (MHD) algorithm to follow the evolution of a simple model of the solar corona in response to the differential rotation of the photospheric magnetic flux. We examine the changes of the coronal-hole boundaries, the redistribution of the line-of-sight magnetic field, and the precession of field lines in the corona. Our results confirm the basic idea of the Fisk model, that differential rotation leads to changes in the heliographic latitude of magnetic field lines. However, the latitudinal excursion of magnetic field lines in this simple "tilted dipole" model is too small to explain the Ulysses observations. Although coronal holes in our model rotate more rigidly than do photospheric features (in general agreement with observations), they do not rotate strictly rigidly as assumed by Fisk. This basic difference between our model and Fisk's will be explored in the future by considering more realistic magnetic flux distributions, as observed during Ulysses polar excursions.

  15. LZIFU: an emission-line fitting toolkit for integral field spectroscopy data

    NASA Astrophysics Data System (ADS)

    Ho, I.-Ting; Medling, Anne M.; Groves, Brent; Rich, Jeffrey A.; Rupke, David S. N.; Hampton, Elise; Kewley, Lisa J.; Bland-Hawthorn, Joss; Croom, Scott M.; Richards, Samuel; Schaefer, Adam L.; Sharp, Rob; Sweet, Sarah M.

    2016-09-01

    We present lzifu (LaZy-IFU), an idl toolkit for fitting multiple emission lines simultaneously in integral field spectroscopy (IFS) data. lzifu is useful for the investigation of the dynamical, physical and chemical properties of gas in galaxies. lzifu has already been applied to many world-class IFS instruments and large IFS surveys, including the Wide Field Spectrograph, the new Multi Unit Spectroscopic Explorer (MUSE), the Calar Alto Legacy Integral Field Area (CALIFA) survey, the Sydney-Australian-astronomical-observatory Multi-object Integral-field spectrograph (SAMI) Galaxy Survey. Here we describe in detail the structure of the toolkit, and how the line fluxes and flux uncertainties are determined, including the possibility of having multiple distinct kinematic components. We quantify the performance of lzifu, demonstrating its accuracy and robustness. We also show examples of applying lzifu to CALIFA and SAMI data to construct emission line and kinematic maps, and investigate complex, skewed line profiles presented in IFS data. The code is made available to the astronomy community through github. lzifu will be further developed over time to other IFS instruments, and to provide even more accurate line and uncertainty estimates.

  16. The Magnification of Atomic Lines Intensity Originated by laser Breakdown in Ultrasound Field

    NASA Astrophysics Data System (ADS)

    Bulanov, A. V.; Nagorny, I. G.

    Atomic lines of some chemical elements like sodium and magnesium were investigated for laser breakdown of water with the ultrasound field. The effect of magnification of these atomic lines resolution for salt water in ultrasound field was obtained. It is shown that the method of registration of acoustic emission from a breakdown zone allows to investigate thresholds and dynamics of laser breakdown which will be in accord with high-speed optical methods. The study revealed important practical applications of acoustic emission for breakdown and diagnostics of cavitation in opaque environments.

  17. Density filament and helical field line structures in three dimensional Weibel-mediated collisionless shocks

    NASA Astrophysics Data System (ADS)

    Moritaka, Toseo; Sakawa, Youichi; Kuramitsu, Yasuhiro; Morita, Taichi; Yamaura, Yuta; Ishikawa, Taishi; Takabe, Hideaki

    2016-03-01

    Collisionless shocks mediated by Weibel instability are attracting attention for their relevance to experimental demonstrations of astrophysical shocks in high-intensity laser facilities. The three dimensional structure of Weibel-mediated shocks is investigated through a fully kinetic particle-in-cell simulation. The structures obtained are characterized by the following features: (i) helical magnetic field lines elongated in the direction upstream of the shock region, (ii) high and low density filaments inside the helical field lines. These structures originate from the interaction between counter-streaming plasma flow and magnetic vortexes caused by Weibel instability, and potentially affect the shock formation mechanism.

  18. Electron polar cap and the boundary of open geomagnetic field lines.

    NASA Technical Reports Server (NTRS)

    Evans, L. C.; Stone, E. C.

    1972-01-01

    A total of 333 observations of the boundary of the polar access region for electrons (energies greater than 530 keV) provides a comprehensive map of the electron polar cap. The boundary of the electron polar cap, which should occur at the latitude separating open and closed field lines, is consistent with previously reported closed field line limits determined from trapped-particle data. The boundary, which is sharply defined, seems to occur at one of three discrete latitudes. Although the electron flux is generally uniform across the polar cap, a limited region of reduced access is observed about 10% of the time.

  19. Investigating the Effect of Line Dipole Magnetic Field on Hydrothermal Characteristics of a Temperature-Sensitive Magnetic Nanofluid Using Two-Phase Simulation.

    PubMed

    Bahiraei, Mehdi; Hangi, Morteza

    2016-12-01

    Hydrothermal characteristics of a temperature-sensitive magnetic nanofluid between two parallel plates are investigated in the presence of magnetic field produced by one or multiple line dipole(s) using the two-phase mixture model. As the nanofluid reaches the region where the magnetic field is applied, a rotation is developed due to the dependency of magnetization on temperature. This can lead to mixing in the flow and more uniform distribution of temperature due to the disturbance caused in the boundary layer, and consequently, enhancement in convective heat transfer. The results indicate that the disturbance in boundary layer adjacent to the lower wall is more significant than the upper wall. By application of the magnetic field, the convective heat transfer increases locally for both walls. Due to the intensified mixing, a sudden pressure drop occurs when the fluid reaches the region where the magnetic field is applied. For greater magnetic field strengths and lower Reynolds numbers, the improvement in convective heat transfer is more significant. For small magnetic field strengths, the effect of applying magnetic field on the upper wall is much smaller than that on the lower wall; however, this effect becomes almost the same for both walls at great magnetic field strengths.

  20. Effects of static magnetic field on human leukemic cell line HL-60.

    PubMed

    Sabo, J; Mirossay, L; Horovcak, L; Sarissky, M; Mirossay, A; Mojzis, J

    2002-05-15

    A number of structures with magnetic moments exists in living organisms that may be oriented by magnetic field. While most experimental efforts belong to the area of effects induced by weak and extremely low-frequency electromagnetic fields, we attempt to give an attention to the biological effects of strong static magnetic fields. The influence of static magnetic field (SMF) on metabolic activity of cells was examined. The metabolic activity retardation is observed in human leukemic cell line HL-60 exposed to 1-T SMF for 72 h. The retardation effect was observed as well as in the presence of the mixture of the antineoplastic drugs 5 fluorouracil, cisplatin, doxorubicin and vincristine.

  1. Study of magnetic fields from power-frequency current on water lines.

    PubMed

    Lanera, D; Zapotosky, J E; Colby, J A

    1997-01-01

    The magnetic fields from power-frequency current flowing on water lines were investigated in a new approach that involved an area-wide survey in a small town. Magnetic fields were measured outside the residence under power cables and over water lines, and each residence was characterized as to whether it received water from a private well or the municipal water system. The magnetic field data revealed two statistical modes when they were related to water supply type. The data also showed that in the case of the high mode, the magnetic field remained constant along the line formed by power drop wires, at the back of the house, and the water hookup service, in front of the house, all the way to the street. The patterns are explained by the coincidence of measurement points and the presence of net current flowing on power mains, power drop conductors, residential plumbing, water service hookups, and water mains. These patterns, together with other characteristics of this magnetic field source, such as the gradual spatial fall-off of this field and the presence of a constant component in the time sequence, portray a magnetic field more uniform and constant in the residential environment than has been thought to exist. Such characteristics make up for the weakness of the source and make net current a significant source of exposure in the lives of individuals around the house, when human exposure to magnetic fields is assumed to be a cumulative effect over time. This, together with the bimodal statistical distribution of the residential magnetic field (related to water supply type), presents opportunities for retrospective epidemiological analysis. Water line type and its ability to conduct power-frequency current can be used as the historical marker for a bimodal exposure inference, as Wertheimer et al. have shown.

  2. Inference of the chromospheric magnetic field orientation in the Ca ii 8542 Å line fibrils

    NASA Astrophysics Data System (ADS)

    Asensio Ramos, A.; de la Cruz Rodríguez, J.; Martínez González, M. J.; Socas-Navarro, H.

    2017-03-01

    Context. Solar chromospheric fibrils, as observed in the core of strong chromospheric spectral lines, extend from photospheric field concentrations suggesting that they trace magnetic field lines. These images have been historically used as proxies of magnetic fields for many purposes. Aims: Use statistical analysis to test whether the association between fibrils and magnetic field lines is justified. Methods: We use a Bayesian hierarchical model to analyze several tens of thousands of pixels in spectro-polarimetric chromospheric images of penumbrae and chromospheric fibrils. We compare the alignment between the field azimuth inferred from the linear polarization signals through the transverse Zeeman effect and the direction of the fibrils in the image. Results: We conclude that, in the analyzed fields of view, fibrils are often well aligned with the magnetic field azimuth. Despite this alignment, the analysis also shows that there is a non-negligible dispersion. In penumbral filaments, we find a dispersion with a standard deviation of 16°, while this dispersion goes up to 34° in less magnetized regions.

  3. On open and closed field line regions in Tsyganenko's field model and their possible associations with horse collar auroras

    NASA Technical Reports Server (NTRS)

    Birn, J.; Hones, E. W., Jr.; Craven, J. D.; Frank, L. A.; Elphinstone, R. D.; Stern, D. P.

    1991-01-01

    The boundary between open and closed field lines is investigated in the empirical Tsyganenko (1987) magnetic field model. All field lines extending to distances beyond -70 R(E), the tailward velocity limit of the Tsyganenko model are defined as open, while all other field lines, which cross the equatorial plane earthward of -70 R(E) and are connected with the earth at both ends, are assumed closed. It is found that this boundary at the surface of the earth, identified as the polar cap boundary, can exhibit the arrowhead shape, pointed toward the sun, which is found in horse collar auroras. For increasing activity levels, the polar cap increases in area and becomes rounder, so that the arrowhead shape is less pronounced. The presence of a net B(y) component can also lead to considerable rounding of the open flux region. The arrowhead shape is found to be closely associated with the increase of B(z) from the midnight region to the flanks of the tail, consistent with a similar increase of the plasma sheet thickness.

  4. Continuum Gyrokinetic Simulations of Turbulence in Open-Field-Line Plasmas

    NASA Astrophysics Data System (ADS)

    Shi, E. L.; Hammett, G. W.; Stoltzfus-Dueck, T.; Hakim, A.

    2016-10-01

    We have performed our first 3D2V gyrokinetic simulations of electrostatic plasma turbulence in open-field-line geometries using the full-F discontinuous-Galerkin code Gkeyll. These simulations include the basic elements of a scrape-off layer: localized sources to model plasma outflow from the core, cross-field turbulent transport, parallel flow along magnetic field lines, and parallel losses at the limiter or divertor with sheath boundary conditions. The set of boundary conditions used in our model allows currents to flow through the walls and satisfies energy conservation. In addition to details of our numerical approach, we will present results from flux-tube simulations of devices containing straight-field lines (such as LAPD) and helical-field-lines (such as the TORPEX simple magnetized torus). Preliminary results show turbulent fluctuation levels similar to fluid simulations, which are comparable to the observed fluctuation level in LAPD but somewhat smaller than observed in TORPEX. This research was supported by the Max-Planck/Princeton Center for Plasma Physics, the SciDAC Center for the Study of Plasma Microturbulence, and U.S. DOE contract DE-AC02-09CH11466.

  5. Observations of a Newly "Captured" Magnetosheath Field Line: Evidence for "Double Reconnection"

    NASA Technical Reports Server (NTRS)

    Chandler, Michael O.; Avanov, Levon A.; Craven, Paul D.; Mozer, Forrest S.; Moore, Thomas E.

    2007-01-01

    We have begun an investigation of the nature of the low-latitude boundary layer in the mid-altitude cusp region using data from the Polar spacecraft. This region has been routinely sampled for about three months each year for the periods 1999-2001 and 2004-2006. The low-to-mid-energy ion instruments frequently observed dense, magnetosheath-like plasma deep (in terms of distance from the magnetopause and in invariant latitude) in the magnetosphere. One such case, taken during a period of northward interplanetary magnetic field (IMF), shows magnetosheath ions within the magnetosphere with velocity distributions resulting from two separate merging sites along the same field lines. Cold ionospheric ions were also observed counterstreaming along the field lines, evidence that these field lines were closed. These results are consistent with the hypothesis that double merging can produce closed field .lines populated by solar wind plasma. Through the use of individual cases such as this and statistical studies of a broader database we seek to understand the morphology of the LLBL as it projects from the sub-solar region into the cusp. We will present preliminary results of our ongoing study.

  6. Impact of Magnetic Draping, Convection, and Field Line Tying on Magnetopause Reconnection Under Northward IMF

    NASA Technical Reports Server (NTRS)

    Wendel, Deirdre E.; Reiff, Patricia H.; Goldstein, Melvyn L.

    2010-01-01

    We simulate a northward IMF cusp reconnection event at the magnetopause using the OpenGGCM resistive MHD code. The ACE input data, solar wind parameters, and dipole tilt belong to a 2002 reconnection event observed by IMAGE and Cluster. Based on a fully three-dimensional skeleton separators, nulls, and parallel electric fields, we show magnetic draping, convection, ionospheric field line tying play a role in producing a series of locally reconnecting nulls with flux ropes. The flux ropes in the cusp along the global separator line of symmetry. In 2D projection, the flux ropes the appearance of a tearing mode with a series of 'x's' and 'o's' but bearing a kind of 'guide field' that exists only within the magnetopause. The reconnecting field lines in the string of ropes involve IMF and both open and closed Earth magnetic field lines. The observed magnetic geometry reproduces the findings of a superposed epoch impact parameter study derived from the Cluster magnetometer data for the same event. The observed geometry has repercussions for spacecraft observations of cusp reconnection and for the imposed boundary conditions reconnection simulations.

  7. Satellite observations of new particle and field signatures associated with SAR arc field lines at magnetospheric heights

    NASA Technical Reports Server (NTRS)

    Kozyra, J. U.; Cravens, T. E.; Nagy, A. F.; Gurnett, D. A.; Huff, R. L.; Comfort, R. H.; Waite, J. H., Jr.; Brace, L. H.

    1987-01-01

    Enhancements in thermal ion densities, an oxygen dominated ring current at energies below 17 keV, and invariant latitude-limited bands of intense ELF hiss have been discovered on Stable Auroral Red (SAR) arc field lines at magnetospheric heights. These new signatures were revealed by an examination of 31 coordinated data sets taken simultaneously at magnetospheric and ionospheric heights by the De-1 and -2 satellites during SAR arc traversals within the period September 1981 through April 1982. Data sets from DE-2, for the first time, provide information on the location of a SAR arc (determined by the F region electron temperature enhancement) during the nearly simultaneous passage of these field lines by DE-1 in the magnetosphere. These new high altitude signatures are examined in the context of possible magnetospheric SAR arc energy source mechanisms.

  8. NEW APPROACHES: Magnetic and electric field strengths of high voltage power lines and household appliances

    NASA Astrophysics Data System (ADS)

    Austin, Lydia

    1997-03-01

    A readily obtainable meter can be used to measure the magnetic and electric field strengths of high voltage power lines and household appliances. Simple calculations show that all likely exposures are below, mostly well below, the maximum exposures recommended by the World Health Organisation.

  9. GAP JUNCTION COMMUNICATON IN A TRANSFECTED HUMAN CELL LINE: ACTION OF MELATONIN AND MAGNETIC FIELDS

    EPA Science Inventory

    GAP JUNCTION COMMUNICTION IN TRANSFECTED HUMAN CELL LINE: ACTION OF MELATONIN AND MAGNETIC FIELDS.

    OBJECTIVE: We previously showed that functional gap junction communication (GJC), as monitored by dye transfer (DT), could be enhanced in mouse C3H 10T112 cells and in mouse...

  10. Study of electric fields parallel to the magnetic lines of force using artificially injected energetic electrons

    NASA Technical Reports Server (NTRS)

    Wilhelm, K.; Bernstein, W.; Whalen, B. A.

    1980-01-01

    Electron beam experiments using rocket-borne instrumentation will be discussed. The observations indicate that reflections of energetic electrons may occur at possible electric field configurations parallel to the direction of the magnetic lines of force in an altitude range of several thousand kilometers above the ionosphere.

  11. Direct design of two freeform optical surfaces for wide field of view line imaging applications

    NASA Astrophysics Data System (ADS)

    Nie, Yunfeng; Thienpont, Hugo; Duerr, Fabian

    2016-04-01

    In this paper, we propose a multi-fields direct design method aiming to calculate two freeform surfaces with an entrance pupil incorporated for wide field of view on-axis line imaging applications. Both infinite and finite conjugate objectives can be designed with this approach. Since a wide angle imaging system requires more than few discrete perfect imaging points, the multi-fields design approach is based on partial coupling of multiple fields, which guarantees a much more balanced imaging performance over the full field of view. The optical path lengths (OPLs) and image points of numerous off-axis fields are calculated during the procedure, thus very few initial parameters are needed. The procedure to calculate such a freeform lens is explained in detail. We have designed an exemplary monochromatic single lens to demonstrate the functionality of the design method. A rotationally symmetric counterpart following the same specifications is compared in terms of RMS spot radius to demonstrate the clear benefit that freeform lens brings to on-axis line imaging systems. In addition, a practical achromatic wide angle objective is designed by combining our multi-fields design method with classic optical design strategies, serving as a very good starting point for further optimization in a commercial optical design program. The results from the perspective of aberrations plots and MTF values show a very good and well balanced performance over the full field of view.

  12. Numerical approximations for a phase-field moving contact line model with variable densities and viscosities

    NASA Astrophysics Data System (ADS)

    Yu, Haijun; Yang, Xiaofeng

    2017-04-01

    We consider the numerical approximations of a two-phase hydrodynamics coupled phase-field model that incorporates the variable densities, viscosities and moving contact line boundary conditions. The model is a nonlinear, coupled system that consists of incompressible Navier-Stokes equations with the generalized Navier boundary condition, and the Cahn-Hilliard equations with moving contact line boundary conditions. By some subtle explicit-implicit treatments to nonlinear terms, we develop two efficient, unconditionally energy stable numerical schemes, in particular, a linear decoupled energy stable scheme for the system with static contact line condition, and a nonlinear energy stable scheme for the system with dynamic contact line condition. An efficient spectral-Galerkin spatial discretization is implemented to verify the accuracy and efficiency of proposed schemes. Various numerical results show that the proposed schemes are efficient and accurate.

  13. Mean-field Density Functional Theory of a Three-Phase Contact Line

    NASA Astrophysics Data System (ADS)

    Lin, Chang-You

    A three-phase contact line in a three-phase fluid system is modeled by a mean-field density functional theory. We use a variational approach to find the Euler-Lagrange equations. Analytic solutions are obtained in the two-phase regions at large distances from the contact line. We employ a triangular grid and use a successive over-relaxation method to find numerical solutions in the entire domain for the special case of equal interfacial tensions for the two-phase interfaces. We use the Kerins-Boiteux formula to obtain a line tension associated with the contact line. This line tension turns out to be negative. We associate line adsorption with the change of line tension as the governing potentials change. We develop a geometrical interpretation to generalize our potential in order to study less symmetric systems as occur in some practical phase diagrams. A set of special cases of this new potential are linear transformations from our original potential. In those special cases, we can obtain solutions by scaling of our former results.

  14. Thermonuclear Supernovae: Probing Magnetic Fields by Positrons and Late-time IR Line Profiles

    NASA Astrophysics Data System (ADS)

    Penney, R.; Hoeflich, P.

    2014-11-01

    We show the importance of γ and positron transport for the formation of late-time spectra in Type Ia supernovae (SNe Ia). The goal is to study the imprint of magnetic fields (B) on late-time IR line profiles, particularly the [Fe II] feature at 1.644 μm, which becomes prominent two to three months after the explosion. As a benchmark, we use the explosion of a Chandrasekhar mass (M Ch) white dwarf (WD) and, specifically, a delayed detonation model that can reproduce the light curves and spectra for a Branch-normal SN Ia. We assume WDs with initial magnetic surface fields between 1 and 109 G. We discuss large-scale dipole and small-scale magnetic fields. We show that positron transport effects must be taken into account for the interpretation of emission features starting at about one to two years after maximum light, depending on the size of B. The [Fe II] line profile and its evolution with time can be understood in terms of the overall energy input by radioactive decay and the transition from a γ-ray to a positron-dominated regime. We find that the [Fe II] line at 1.644 μm can be used to analyze the overall chemical and density structure of the exploding WD up to day 200 without considering B. At later times, positron transport and magnetic field effects become important. After about day 300, the line profile allows one to probe the size of the B-field. The profile becomes sensitive to the morphology of B at about day 500. In the presence of a large-scale dipole field, a broad line is produced in M Ch mass explosions that may appear flat-topped or rounded depending on the inclination at which the SN is observed. Small or no directional dependence of the spectra is found for small-scale B. We note that narrow-line profiles require central 56Ni as shown in our previous studies. Persistent broad-line, flat-topped profiles require high-density burning, which is the signature of a WD close to M Ch. Good time coverage is required to separate the effects of optical

  15. Reduction of the Earth's magnetic field inhibits growth rates of model cancer cell lines.

    PubMed

    Martino, Carlos F; Portelli, Lucas; McCabe, Kevin; Hernandez, Mark; Barnes, Frank

    2010-12-01

    Small alterations in static magnetic fields have been shown to affect certain chemical reaction rates ex vivo. In this manuscript, we present data demonstrating that similar small changes in static magnetic fields between individual cell culture incubators results in significantly altered cell cycle rates for multiple cancer-derived cell lines. This change as assessed by cell number is not a result of apoptosis, necrosis, or cell cycle alterations. While the underlying mechanism is unclear, the implications for all cell culture experiments are clear; static magnetic field conditions within incubators must be considered and/or controlled just as one does for temperature, humidity, and carbon dioxide concentration.

  16. Singular surfaces in the open field line region of a diverted tokamak

    SciTech Connect

    Reiman, A.

    1995-05-01

    The structure of the open field lines of a slightly nonaxisymmetric, poloidally diverted tokamak is explored by numerical integration of the field line equations for a simple model field. In practice, the nonaxisymmetry could be produced self-consistently by the nonlinear evolution of a free-boundary MHD mode, or it could be produced by field errors, or it could be imposed externally by design. In the presence of a nonaxisymmetric perturbation, the tokamak is shown to develop open field line regions of differing topology separated by singular surfaces. It is argued that the singular surfaces can be expected to play a role analogous to that of rational toroidal flux surfaces, in terms of constraining ideal MHD perturbations and thus constraining the free-energy that can be tapped by ideal MHD instabilities. The possibility of active control of free-boundary instabilities by means of currents driven on the open singular surfaces, which are directly accessible from the divertor plates, is discussed. Also discussed is the possibility of early detection of imminent disruptions through localized measurement of the singular surface currents.

  17. Stable anisotropic plasma confinement in magnetic configurations with convex-concave field lines

    NASA Astrophysics Data System (ADS)

    Tsventoukh, M. M.

    2014-02-01

    It is shown that a combination of the convex and the concave part of a field line provides a strong stabilizing action against convective (flute-interchange) plasma instability (Tsventoukh 2011 Nucl. Fusion 51 112002). This results in internal peaking of the stable plasma pressure profile that is calculated from the collisionless kinetic stability criterion for any magnetic confinement system with combination of mirrors and cusps. Connection of the convex and concave field line parts results in a reduction of the space charge that drives the unstable E × B motion, as there is an opposite direction of the particle drift in a non-uniform field at convex and concave field lines. The pressure peaking arises at the minimum of the second adiabatic invariant J that takes place at the ‘middle’ of a tandem mirror-cusp transverse cross-section. The position of the minimum in J varies with the particle pitch angle that results in a shift of the peaking position depending on plasma anisotropy. This allows one to improve a stable peaked pressure profile at a convex-concave field by changing the plasma anisotropy over the trap cross-section. Examples of such anisotropic distribution functions are found that give an additional substantial enhancement in the maximal central pressure. Furthermore, the shape of new calculated stable profiles has a wide central plasma layer instead of a narrow peak.

  18. Determination of High-Frequency Current Distribution Using EMTP-Based Transmission Line Models with Resulting Radiated Electromagnetic Fields

    SciTech Connect

    Mork, B; Nelson, R; Kirkendall, B; Stenvig, N

    2009-11-30

    Application of BPL technologies to existing overhead high-voltage power lines would benefit greatly from improved simulation tools capable of predicting performance - such as the electromagnetic fields radiated from such lines. Existing EMTP-based frequency-dependent line models are attractive since their parameters are derived from physical design dimensions which are easily obtained. However, to calculate the radiated electromagnetic fields, detailed current distributions need to be determined. This paper presents a method of using EMTP line models to determine the current distribution on the lines, as well as a technique for using these current distributions to determine the radiated electromagnetic fields.

  19. Flow downstream of the heliospheric terminal shock: Magnetic field line topology and solar cycle imprint

    NASA Technical Reports Server (NTRS)

    Nerney, Steven; Suess, S. T.; Schmahl, E. J.

    1995-01-01

    The topology of the magnetic field in the heliosheath is illustrated using plots of the field lines. It is shown that the Archimedean spiral inside the terminal shock is rotated back in the heliosheath into nested spirals that are advected in the direction of the interstellar wind. The 22-year solar magnetic cycle is imprinted onto these field lines in the form of unipolar magnetic envelopes surrounded by volumes of strongly mixed polarity. Each envelope is defined by the changing tilt of the heliospheric current sheet, which is in turn defined by the boundary of unipolar high-latitude regions on the Sun that shrink to the pole at solar maximum and expand to the equator at solar minimum. The detailed shape of the envelopes is regulated by the solar wind velocity structure in the heliosheath.

  20. Transmission line relay mis-operation detection based on time-synchronized field data

    DOE PAGES

    Esmaeilian, Ahad; Popovic, Tomo; Kezunovic, Mladen

    2015-05-04

    In this paper, a real-time tool to detect transmission line relay mis-operation is implemented. The tool uses time-synchronized measurements obtained from both ends of the line during disturbances. The proposed fault analysis tool comes into the picture only after the protective device has operated and tripped the line. The proposed methodology is able not only to detect, classify, and locate transmission line faults, but also to accurately confirm whether the line was tripped due to a mis-operation of protective relays. The analysis report includes either detailed description of the fault type and location or detection of relay mis-operation. As such,more » it can be a source of very useful information to support the system restoration. The focus of the paper is on the implementation requirements that allow practical application of the methodology, which is illustrated using the field data obtained the real power system. Testing and validation is done using the field data recorded by digital fault recorders and protective relays. The test data included several hundreds of event records corresponding to both relay mis-operations and actual faults. The discussion of results addresses various challenges encountered during the implementation and validation of the presented methodology.« less

  1. Transmission line relay mis-operation detection based on time-synchronized field data

    SciTech Connect

    Esmaeilian, Ahad; Popovic, Tomo; Kezunovic, Mladen

    2015-05-04

    In this paper, a real-time tool to detect transmission line relay mis-operation is implemented. The tool uses time-synchronized measurements obtained from both ends of the line during disturbances. The proposed fault analysis tool comes into the picture only after the protective device has operated and tripped the line. The proposed methodology is able not only to detect, classify, and locate transmission line faults, but also to accurately confirm whether the line was tripped due to a mis-operation of protective relays. The analysis report includes either detailed description of the fault type and location or detection of relay mis-operation. As such, it can be a source of very useful information to support the system restoration. The focus of the paper is on the implementation requirements that allow practical application of the methodology, which is illustrated using the field data obtained the real power system. Testing and validation is done using the field data recorded by digital fault recorders and protective relays. The test data included several hundreds of event records corresponding to both relay mis-operations and actual faults. The discussion of results addresses various challenges encountered during the implementation and validation of the presented methodology.

  2. Lines

    ERIC Educational Resources Information Center

    Mires, Peter B.

    2006-01-01

    National Geography Standards for the middle school years generally stress the teaching of latitude and longitude. There are many creative ways to explain the great grid that encircles our planet, but the author has found that students in his college-level geography courses especially enjoy human-interest stories associated with lines of latitude…

  3. In-flight near- and far-field acoustic data measured on the Propfan Test Assessment (PTA) testbed and with an adjacent aircraft

    NASA Technical Reports Server (NTRS)

    Woodward, Richard P.; Loeffler, Irvin J.

    1993-01-01

    Flight tests to define the far-field tone source at cruise conditions were completed on the full-scale SR-7L advanced turboprop that was installed on the left wing of a Gulfstream 2 aircraft. This program, designated Propfan Test Assessment (PTA), involved aeroacoustic testing of the propeller over a range of test conditions. These measurements defined source levels for input into long-distance propagation models to predict en route noise. In-flight data were taken for seven test cases. Near-field acoustic data were taken on the Gulfstream fuselage and on a microphone boom that was mounted on the Gulfstream wing outboard of the propeller. Far-field acoustic data were taken by an acoustically instrumented Learjet that flew in formation with the Gulfstream. These flight tests were flown from El Paso, Texas, and from the NASA Lewis Research Center. A comprehensive listing of the aeroacoustic results from these flight tests which may be used for future analysis are presented.

  4. The magnetic field of the double-lined spectroscopic binary system HD 5550

    NASA Astrophysics Data System (ADS)

    Alecian, E.; Tkachenko, A.; Neiner, C.; Folsom, C. P.; Leroy, B.

    2016-05-01

    Context. The origin of fossil fields in intermediate- and high-mass stars is poorly understood, as is the interplay between binarity and magnetism during stellar evolution. Thus we have begun a study of the magnetic properties of a sample of intermediate-mass and massive short-period binary systems as a function of binarity properties. Aims: This paper specifically aims to characterise the magnetic field of HD 5550, a double-lined spectroscopic binary system of intermediate mass. Methods: We gathered 25 high-resolution spectropolarimetric observations of HD 5550 using the instrument Narval. We first fitted the intensity spectra using Zeeman/ATLAS9 LTE synthetic spectra to estimate the effective temperatures, microturbulent velocities, and the abundances of some elements of both components, as well as the light ratio of the system. We then applied the multi-line least-square deconvolution (LSD) technique to the intensity and circularly polarised spectra, which provided us with mean LSD I and V line profiles. We fitted the Stokes I line profiles to determine the radial and projected rotational velocities of both stars. We then analysed the shape and evolution of the V profiles using the oblique rotator model to characterise the magnetic fields of both stars. Results: We confirm the Ap nature of the primary, which has previously been reported, and find that the secondary displays spectral characteristics typical of an Am star. While a magnetic field is clearly detected in the lines of the primary, no magnetic field is detected in the secondary in any of our observations. If a dipolar field were present at the surface of the Am star, its polar strength must be below 40 G. The faint variability observed in the Stokes V profiles of the Ap star allowed us to propose a rotation period of 6.84-0.39+0.61 d, which is close to the orbital period (~6.82 d), suggesting that the star is synchronised with its orbit. By fitting the variability of the V profiles, we propose that the

  5. Association between Exposure to Electromagnetic Fields from High Voltage Transmission Lines and Neurobehavioral Function in Children

    PubMed Central

    Huang, Jiongli; Tang, Tiantong; Hu, Guocheng; Zheng, Jing; Wang, Yuyu; Wang, Qiang; Su, Jing; Zou, Yunfeng; Peng, Xiaowu

    2013-01-01

    Background Evidence for a possible causal relationship between exposure to electromagnetic fields (EMF) emitted by high voltage transmission (HVT) lines and neurobehavioral dysfunction in children is insufficient. The present study aims to investigate the association between EMF exposure from HVT lines and neurobehavioral function in children. Methods Two primary schools were chosen based on monitoring data of ambient electromagnetic radiation. A cross-sectional study with 437 children (9 to 13 years old) was conducted. Exposure to EMF from HVT lines was monitored at each school. Information was collected on possible confounders and relevant exposure predictors using standardized questionnaires. Neurobehavioral function in children was evaluated using established computerized neurobehavioral tests. Data was analyzed using multivariable regression models adjusted for relevant confounders. Results After controlling for potential confounding factors, multivariable regression revealed that children attending a school near 500 kV HVT lines had poorer performance on the computerized neurobehavioral tests for Visual Retention and Pursuit Aiming compared to children attending a school that was not in close proximity to HVT lines. Conclusions The results suggest long-term low-level exposure to EMF from HVT lines might have a negative impact on neurobehavioral function in children. However, because of differences in results only for two of four tests achieved statistical significance and potential limitations, more studies are needed to explore the effects of exposure to extremely low frequency EMF on neurobehavioral function and development in children. PMID:23843999

  6. STRONG FIELD EFFECTS ON EMISSION LINE PROFILES: KERR BLACK HOLES AND WARPED ACCRETION DISKS

    SciTech Connect

    Wang Yan; Li Xiangdong

    2012-01-10

    If an accretion disk around a black hole is illuminated by hard X-rays from non-thermal coronae, fluorescent iron lines will be emitted from the inner region of the accretion disk. The emission line profiles will show a variety of strong field effects, which may be used as a probe of the spin parameter of the black hole and the structure of the accretion disk. In this paper, we generalize the previous relativistic line profile models by including both the black hole spinning effects and the non-axisymmetries of warped accretion disks. Our results show different features from the conventional calculations for either a flat disk around a Kerr black hole or a warped disk around a Schwarzschild black hole by presenting, at the same time, multiple peaks, rather long red tails, and time variations of line profiles with the precession of the disk. We show disk images as seen by a distant observer, which are distorted by the strong gravity. Although we are primarily concerned with the iron K-shell lines in this paper, the calculation is general and is valid for any emission lines produced from a warped accretion disk around a black hole.

  7. THE MECHANISMS OF ELECTRON ACCELERATION DURING MULTIPLE X LINE MAGNETIC RECONNECTION WITH A GUIDE FIELD

    SciTech Connect

    Wang, Huanyu; Lu, Quanming; Huang, Can; Wang, Shui

    2016-04-20

    The interactions between magnetic islands are considered to play an important role in electron acceleration during magnetic reconnection. In this paper, two-dimensional particle-in-cell simulations are performed to study electron acceleration during multiple X line reconnection with a guide field. Because the electrons remain almost magnetized, we can analyze the contributions of the parallel electric field, Fermi, and betatron mechanisms to electron acceleration during the evolution of magnetic reconnection through comparison with a guide-center theory. The results show that with the magnetic reconnection proceeding, two magnetic islands are formed in the simulation domain. Next, the electrons are accelerated by both the parallel electric field in the vicinity of the X lines and the Fermi mechanism due to the contraction of the two magnetic islands. Then, the two magnetic islands begin to merge into one, and, in such a process, the electrons can be accelerated by both the parallel electric field and betatron mechanisms. During the betatron acceleration, the electrons are locally accelerated in the regions where the magnetic field is piled up by the high-speed flow from the X line. At last, when the coalescence of the two islands into one big island finishes, the electrons can be further accelerated by the Fermi mechanism because of the contraction of the big island. With the increase of the guide field, the contributions of the Fermi and betatron mechanisms to electron acceleration become less and less important. When the guide field is sufficiently large, the contributions of the Fermi and betatron mechanisms are almost negligible.

  8. Evidence and relevance of spatially chaotic magnetic field lines in MCF devices

    NASA Astrophysics Data System (ADS)

    Firpo, M.-C.; Lifschitz, A. F.; Ettoumi, W.; Farengo, R.; Ferrari, H. E.; García-Martínez, P. L.

    2017-03-01

    Numerical evidence for the existence of spatially chaotic magnetic field lines about the collapse phase of tokamak sawteeth with incomplete reconnection is presented. This uses the results of extensive test particle simulations in different sets of electromagnetic perturbations tested against experimental JET measurements. In tokamak sawteeth, that form a laboratory prototype of magnetic reconnection, the relative magnetic perturbation δ B/B may reach a few percents. This does not apply to tokamak operating regimes dominated by turbulence where δ B/B is usually not larger than {10}-4. However, this small magnetic perturbation being sustained by a large spectrum of modes is shown to be sufficient to ensure the existence of stochastic magnetic field lines. This has important consequences for magnetic confinement fusion where electrons are dominantly governed by the magnetic force. Indeed some overlap between magnetic resonances can locally induce chaotic magnetic field lines enabling the spatial redistribution of the electron population and of its thermal content. As they are the swiftest plasma particles, electrons feed back the most rapid perturbations of the magnetic field.

  9. Dynamic effects of restoring footpoint symmetry on closed magnetic field lines

    NASA Astrophysics Data System (ADS)

    Reistad, J. P.; Østgaard, N.; Tenfjord, P.; Laundal, K. M.; Snekvik, K.; Haaland, S.; Milan, S. E.; Oksavik, K.; Frey, H. U.; Grocott, A.

    2016-05-01

    Here we present an event where simultaneous global imaging of the aurora from both hemispheres reveals a large longitudinal shift of the nightside aurora of about 3 h, being the largest relative shift reported on from conjugate auroral imaging. This is interpreted as evidence of closed field lines having very asymmetric footpoints associated with the persistent positive y component of the interplanetary magnetic field before and during the event. At the same time, the Super Dual Auroral Radar Network observes the ionospheric nightside convection throat region in both hemispheres. The radar data indicate faster convection toward the dayside in the dusk cell in the Southern Hemisphere compared to its conjugate region. We interpret this as a signature of a process acting to restore symmetry of the displaced closed magnetic field lines resulting in flux tubes moving faster along the banana cell than the conjugate orange cell. The event is analyzed with emphasis on Birkeland currents (BC) associated with this restoring process, as recently described by Tenfjord et al. (2015). Using data from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) during the same conditions as the presented event, the large-scale BC pattern associated with the event is presented. It shows the expected influence of the process of restoring symmetry on BCs. We therefore suggest that these observations should be recognized as being a result of the dynamic effects of restoring footpoint symmetry on closed field lines in the nightside.

  10. Development of phosphor imaging diagnostics for particle energization and field line mapping studies in MRX

    NASA Astrophysics Data System (ADS)

    Fox, W.; Zweben, S. J.; Yoo, J.; Jara-Almonte, J.; Myers, C.; Yamada, M.; Ji, H.

    2014-10-01

    The energization of particles by magnetic reconnection is one of its most important roles in space and astrophysical plasmas. We present results from phosphor-screen imaging diagnostics for the Magnetic Reconnection Experiment, developed to measure the location and timing of particle energization by magnetic reconnection and to map field lines. Phosphor-based imaging diagnostics have previously been to study plasma dynamics in in non-neutral plasmas and low-temperature linear machines. In MRX, movable, phosphor-coated probes are scanned across the current sheet, and phosphor emission is imaged on a fast camera acquiring at typically 500 k frames/sec. Optical filters isolate the phosphor emission from line emission in the plasma. The energy sensitivity of the probe is determined by the characteristics of the phosphor and bias of the probe with respect to the plasma. We also present the development of an e-beam diagnostic to directly map the magnetic field line structure and possibly to measure the parallel electric field and/or cross-field electron transport. A modulated electron beam from a hot tungsten filament will be detected downstream by Langmuir probes and the phosphor imager.

  11. Electromagnetic fields and cancer in children residing near Norwegian high-voltage power lines.

    PubMed

    Tynes, T; Haldorsen, T

    1997-02-01

    The aim of the nested case-control study reported here was to test the hypothesis that exposure to electromagnetic fields of the type generated by high-voltage power lines increases the incidence of cancer in children aged 0-14 years. The study population comprised children who during at least one of the years 1960, 1970, 1980, 1985, 1987, or 1989 had lived in a census ward crossed by a high-voltage power line. The cases were diagnosed from 1965 to 1989 and were matched to controls by year of birth, sex, and municipality. Exposure to electric and magnetic fields was calculated by means of computer programs in which power line characteristics and distance were taken into account. No association was found between exposure to time-weighted average exposure to magnetic fields and cancer at all sites, brain tumors, lymphoma, or leukemia. Cancer at other sites showed elevated odds ratios in the two highest exposure categories in some, but not all, measures of exposure. This study provides little support for an association between children's exposure to magnetic fields and cancer and no support for an association between leukemia and such exposure, but no firm conclusions can be drawn owing to the small numbers involved.

  12. Lightning and Electric Field Structure of a Squall Line During TELEX

    NASA Astrophysics Data System (ADS)

    Macgorman, D.; Rust, D.; Bruning, E.; Ramig, N.; Apostolakopoulos, I.; Schuur, T.; Biggerstaff, M.; Straka, J.; Krehbiel, P.; Rison, B.; Hamlin, T.

    2004-12-01

    During the 2004 field program for the Thunderstorm Electrification and Lightning Experiment (TELEX), simultaneous electric field soundings, three-dimensional lightning mapping observations, high-resolution Doppler radar data, polarimetric radar data, and environmental soundings were acquired for several mesoscale convective systems, supercell storms, and non-severe thunderstorms. The overall data set was of particularly high quality for a squall line that produced frequent lightning in southern and central Oklahoma on the morning of 19 June 2004. A total of five balloon-borne electric field soundings were launched into the leading line of convection and into the trailing stratiform region. Two 5-cm wavelength mobile Doppler radars (SMART-R's) provided coordinated volume scans every 3 min throughout the period of operations. Furthermore, all operations were well within range of the 10-cm wavelength polarimetric radar and the three-dimensional lightning mapping array. This presentation will emphasize lightning mapping and electric field observations to characterize the electrical behavior of the convective line and the stratiform region.

  13. On the reconstructing the coronal magnetic field from Fe XIII 10747 A emission line observations

    NASA Astrophysics Data System (ADS)

    Kramar, M.; Lin, H.; Inhester, B.

    2009-12-01

    Magnetic fields in the solar corona are the dominant fields that determine the static and dynamic properties of this outermost region of the solar atmosphere. It is within this tenuous region that the magnetic force dominates the gas pressure. Direct measurement of the coronal magnetic field is one of the most challenging problems in observational solar astronomy. To date, one of the promising measurement methods that have been successfully demonstrated is the spectropolarimetric measurement of the Fe XIII 10747 A forbidden emission line (CEL) (Lin, Penn, Tomczyk 2000; Lin, Kuhn, Coulter 2004; Tomczyk et al. 2007) formed due to Hanle and Zeeman effects. However, because coronal measurements are integrated over line-of-site (LOS), it is impossible to derive the configuration of the coronal magnetic field from a single observation (from a single viewing direction). Recent development in vector tomography techniques based on IR forbidden CEL polarization measurements from several viewing direction (Kramar, Inhester, Solanki 2006; Kramar, Inhester 2007) has the potential to resolve the 3D coronal magnetic field structure. In this paper, we will present a study of the effects of instrumental characteristics on the results of vector tomographic inversion using simulated data. We also investigate the sensitivity of the vector tomographic inversion to different coronal magnetic field configuration.

  14. Field-Line Tracing from Locations of Polar Cap Neutral Density Anomalies to the Magnetosphere

    NASA Astrophysics Data System (ADS)

    Sutton, E. K.; Lin, C. S.; Huang, C. Y.; Cooke, D. L.

    2015-12-01

    Localized neutral density enhancement in the polar cap above 70o magnetic latitude have been frequently observed during major geomagnetic storms. It has been suggested that energy input responsible for producing localized neutral density spikes is the dominant energy deposition in the polar cap. To better understand the origin of polar cap neutral density anomalies (PCNDAs) we trace magnetic field lines from the polar cap region at about 400 km to the magnetosphere using the data-based Tsyganenko magnetic field model TS05 [Tsyganenko and Sitnov, 2005] for the periods when CHAMP detected PCNDAs during major magnetic storms with the minimum Dst < -100 nT. The magnetopause boundary is specified according to the three-dimensional asymmetric magnetopause model recently developed by Lin et al. [2010]. The closest distance to the magnetopause along the traced field line path is determined as a function of time. The tracing results indicate that depending on Dst and locations PCNDAs could be connected through magnetic field lines either to the nightside magnetopause or to the magnetotail lobe. For some events field lines originating from a portion of the PCNDA region are found to cross the equatorial plane in the near earth tail region. We discuss the results to help elucidate the coupling between the magnetosphere and the thermosphere and its roles in producing polar cap density anomalies. ReferencesLin, R. L., X. X. Zhang, S. Q. Liu, Y. L. Wang, and J. C. Gong (2010), A three-dimensional asymmetric magnetopause model, J. Geophys. Res., 115, A04207, doi:10.1029/2009JA014235.Tsyganenko, N. A., and M. I. Sitnov (2005), Modeling the dynamics of the inner magnetosphere during strong geomagnetic storms, J. Geophys. Res., 110, A03208, doi:10.1029/2004JA010798.

  15. Beyond Zeeman spectroscopy: Magnetic-field diagnostics with Stark-dominated line shapes

    SciTech Connect

    Tessarin, S.; Mikitchuk, D.; Doron, R.; Stambulchik, E.; Kroupp, E.; Maron, Y.; Hammer, D. A.; Jacobs, V. L.; Seely, J. F.; Oliver, B. V.; Fisher, A.

    2011-09-15

    A recently suggested spectroscopic approach for magnetic-field determination in plasma is employed to measure magnetic fields in an expanding laser-produced plasma plume in an externally applied magnetic field. The approach enables the field determination in a diagnostically difficult regime for which the Zeeman-split patterns are not resolvable, as is often encountered under the conditions characteristic of high-energy-density plasmas. Here, such conditions occur in the high-density plasma near the laser target, due to the dominance of Stark broadening. A pulsed-power system is used to generate magnetic fields with a peak magnitude of 25 T at the inner-electrode surface in a coaxial configuration. An aluminum target attached to the inner electrode surface is then irradiated by a laser beam to produce the expanding plasma that interacts with the applied azimuthal magnetic field. A line-shape analysis of the Al III 4s-4p doublet (5696 and 5722 A) enables the simultaneous determination of the magnetic field and the electron density. The measured magnetic fields are generally found to agree with those expected in a vacuum based on the pulsed-power system current. Examples of other transitions that can be used to diagnose a wide range of plasma and magnetic field parameters are presented.

  16. On open and closed field line regions in Tsyganenko's field model and their possible associations with horse collar auroras

    SciTech Connect

    Birn, J.; Hones, E.W. Jr. ); Craven, J.D.; Frank, L.A. ); Elphinstone, R.D. ); Stern, D.P. )

    1991-03-01

    Using the empirical Tsyganenko (1987) long model as a prime example of a megnetospheric field model, the authors have attempted to identify the boundary between open and closed field lines. They define as closed all field lines that are connested with the Earth at both ends and cross the equatorial plane earthward of x = {minus}70 R{sub E}, the tailward validity limit of the Tsyganenko model. They find that the form of the open/closed boundary at the Earth's surface, identified with the polar cap boundary, can exhibit the arrowhead shape, pointed toward the Sun, observed in horse collar auroras (Hones et al., 1989). The polar cap size in the Tsyganenko model increases with increasing K{sub p} values, and it becomes rounder and less pointed. The superposition of a net B{sub y} field, which is the expected consequence of an IMF B{sub y}, rotates the polar cap pattern and, for larger values, degrades the arrowhead shape, resulting in polar cap configurations consistent with known asymmetries in the aurora. The pointedness of the polar cap shape also diminishes or even completely disappears if the low-latitude magnetopause is assumed open and located considerably inside of the outermost magnetic flux surface in the Tsyganenko model. The arrowhead shape of the polar cap is found to be associated with a strong increase of B{sub z} from midnight toward the tail flanks, which is observed independently, and is possibly related to the NBZ field-aligned current system, observed during quiet times and strongly northward IMF B{sub z}. The larger B{sub z} values near the flanks of the tail cause more magnetic flux to close through these regions than through the midnight equatorial region.

  17. Spectroscopic Properties of Selected Narrow Emission Line Galaxies from the COSMOS Field

    NASA Astrophysics Data System (ADS)

    Colon, Amy M.; Carroll, P.; Roberts, R.; Wong, N.; Liu, C.

    2007-12-01

    We present properties of seven blue narrow emission line galaxies (NELGs) in the redshift range 0.25 < z < 0.73, initially selected as QSO candidates in the COSMOS 2-degree survey field. These galaxies have been selected for the high signal-to-noise of their spectra, as indicated by the presence of the emission line [NeIII] 3869 Angstroms. Emission line diagnostics are used to measure metallicities and star formation rates, and to test the presence of AGN. Hubble ACS images are used to measure their surface brightness distributions and quantitative morphologies. Preliminary results indicate that these objects are forming stars at a rate of 4 to 20 solar masses per year; and their metallicity appears not to vary with the galaxy's concentration index which ranges 0.42 to 0.63.

  18. Zeeman-Doppler Imaging of Stellar Magnetic Fields with Atomic and Molecular Lines

    NASA Astrophysics Data System (ADS)

    Sennhauser, C.; Berdyugina, S. V.; Fluri, D. M.

    2009-06-01

    We have developed a new code for Zeeman-Doppler Imaging (ZDI) of stellar magnetic fields using the Occamian approach for solving inverse problems. The inversions are applied to Stokes I and V parameter sets obtained by solving the full set of polarized radiative transfer equations for both atomic and molecular lines. For the first time we demonstrate that molecular polarization strongly constrains the ZDI maps and is crucial for obtaining a realistic solution from Stokes I and V only observed at a few stellar rotational phases. We also present an enhanced LSD technique, which allows analytic separation of blended line profiles. The resulting LSD profiles are free from systematic effects induced by blends, which are typical for other multi-line techniques.

  19. Coupled microstrip line transverse electromagnetic resonator model for high-field magnetic resonance imaging.

    PubMed

    Bogdanov, G; Ludwig, R

    2002-03-01

    The performance modeling of RF resonators at high magnetic fields of 4.7 T and more requires a physical approach that goes beyond conventional lumped circuit concepts. The treatment of voltages and currents as variables in time and space leads to a coupled transmission line model, whereby the electric and magnetic fields are assumed static in planes orthogonal to the length of the resonator, but wave-like along its longitudinal axis. In this work a multiconductor transmission line (MTL) model is developed and successfully applied to analyze a 12-element unloaded and loaded microstrip line transverse electromagnetic (TEM) resonator coil for animal studies. The loading involves a homogeneous cylindrical dielectric insert of variable radius and length. This model formulation is capable of estimating the resonance spectrum, field distributions, and certain types of losses in the coil, while requiring only modest computational resources. The boundary element method is adopted to compute all relevant transmission line parameters needed to set up the transmission line matrices. Both the theoretical basis and its engineering implementation are discussed and the resulting model predictions are placed in context with measurements. A comparison between a conventional lumped circuit model and this distributed formulation is conducted, showing significant departures in the resonance response at higher frequencies. This MTL model is applied to simulate two small-bore animal systems: one of 7.5-cm inner diameter, tuned to 200 MHz (4.7 T for proton imaging), and one of 13.36-cm inner diameter, tuned to both 200 and 300 MHz (7 T).

  20. Field Performance of Transgenic Sugarcane Lines Resistant to Sugarcane Mosaic Virus

    PubMed Central

    Yao, Wei; Ruan, Miaohong; Qin, Lifang; Yang, Chuanyu; Chen, Rukai; Chen, Baoshan; Zhang, Muqing

    2017-01-01

    Sugarcane mosaic disease is mainly caused by the sugarcane mosaic virus (SCMV), which can significantly reduce stalk yield and sucrose content of sugarcane in the field. Coat protein mediated protection (CPMP) is an effective strategy to improve virus resistance. A 2-year field study was conducted to compare five independent transgenic sugarcane lines carrying the SCMV-CP gene (i.e., B2, B36, B38, B48, and B51) with the wild-type parental clone Badila (WT). Agronomic performance, resistance to SCMV infection, and transgene stability were evaluated and compared with the wild-type parental clone Badila (WT) at four experimental locations in China across two successive seasons, i.e., plant cane (PC) and 1st ratoon cane (1R). All transgenic lines derived from Badila had significantly greater tons of cane per hectare (TCH) and tons of sucrose per hectare (TSH) as well as lower SCMV disease incidence than those from Badila in the PC and 1R crops. The transgenic line B48 was highly resistant to SCMV with less than 3% incidence of infection. The recovery phenotype of transgenic line B36 was infected soon after virus inoculation, but the subsequent leaves showed no symptoms of infection. Most control plants developed symptoms that persisted and spread throughout the plant with more than 50% incidence. B48 recorded an average of 102.72 t/ha, which was 67.2% more than that for Badila. The expression of the transgene was stable over many generations with vegetative propagation. These results show that SCMV-resistant transgenic lines derived from Badila can provide resistant germplasm for sugarcane breeding and can also be used to study virus resistance mechanisms. This is the first report on the development and field performance of transgenic sugarcane plants that are resistant to SCMV infection in China. PMID:28228765

  1. Implications of the equipotential field line approximation for equatorial spread F analysis

    NASA Astrophysics Data System (ADS)

    Aveiro, H. C.; Hysell, D. L.

    2012-06-01

    Three different approaches to the evaluation of the electrostatic potential in the ionosphere under equatorial spread F (ESF) conditions are considered. First, we calculate the potential using an analytical approach, applying force balance laws to a simplified ionosphere. Second, we compute the potential around a cylinder-like plasma depletion in an idealized ionosphere using both the equipotential field line (EFL) approach and the full 3-D solution to the electrostatic potential problem. Our third approach involves an initial boundary value simulation in a realistic ionosphere using both EFL and 3-D potential solutions. The results show that the equipotential field line assumption does not fully capture the 3-D structure of the ionospheric current system and leads to an underestimation of the growth rate of ESF irregularities in numerical simulations.

  2. Implications of Field Line Tracing for Power and Particle Handling in NCSX

    NASA Astrophysics Data System (ADS)

    Grossman, A.; Mioduszewki, P. K.

    2002-11-01

    Recent experience with power and particle handling in W7-AS shows that there is substantial improvement when the plasma-wall interaction is systematized with the use of a divertor. The improvements with a divertor include achievement of record values of beta, increases in energy confinement with density, decreases in impurity and particle confinement and full density control. With the healing of islands just inside the LCMS of NCSX, the finite beta tracing of field lines outside of the LCMS via the MFBE_2001 code shows that a sufficiently long connection length (>100m) can be achieved to yield a temperature separation between divertor and LCMS sufficiently large for divertor operation. Significant flux expansion and stochastic field line structure with Kolmogorov lengths measuring several toroidal revolutions suggests that the divertor is a feasible option for NCSX.

  3. A theory of electron cyclotron waves generated along auroral field lines observed by ground facilities

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Yoon, Peter H.; Freund, H. P.

    1989-01-01

    A generation mechanism for radio waves in the frequency range 150 - 700 kHz observed by ground facilities is suggested in terms of an electromagnetic electron cyclotron instability driven by auroral electrons. The excited waves can propagate downward along the ambient magnetic field lines and are thus observable with ground facilities. The trapped auroral electrons are supposed to play an important role in the generation process, because they give rise to a thermal anisotropy which consequently leads to the instability. The present work is a natural extension of the theory proposed earlier by Wu et al. (1983) which was discussed in a different context but may be used to explain the observed waves originated at low altitudes. This paper presents a possible wave generation mechanism valid in the entire auroral field-line region of interest.

  4. Induced fields, charges and currents on a lineman engaged in transmission-line insulator washing

    SciTech Connect

    Abdel-Salam, M.; El-Mohandes, M.T.; Alghamdi, A.S.

    1995-12-31

    This paper is aimed to calculate the distribution of the field, induced charges and currents on a lineman engaged in transmission-line insulator washing. The method of analysis is based on the charge simulation technique. The lineman is modeled by small sphere for the head and a large sphere for the body. For simplicity, the tower is chosen of the duct type and the insulator of the suspension type. The transmission-line conductor is simulated by finite and semi-infinite line charges to account for the nonuniform distribution of conductor charge resulting from the suspension insulator and the supporting tower. As the purity of the washing water is high, the water spray is simulated by a thin conducting stick extending between the column insulator and the lineman sitting on the crossarm of the tower. This represents a three-dimensional field problem and care has been devoted in the choice of the number and coordinates of charges simulating the tower, the insulator, the conductor, the water spray and the lineman. The induced currents increase as the lineman approaches the insulator with the suspended line conductor. These currents are higher than those for insulated lineman and may exceed the safe limits.

  5. Radiative widths and splitting of cyclotron lines in superstrong magnetic fields

    NASA Technical Reports Server (NTRS)

    Pavlov, G. G.; Bezchastnov, V. G.; Meszaros, P.; Alexander, S. G.

    1991-01-01

    The radiative line widths of the Landau levels in a superstrong magnetic field are calculated and simple analytic expressions and fits are given for these which are valid over a wide range of the principal quantum number and the magnetic field strength. If QED corrections are not taken into account, all levels but the first are doubly degenerate, corresponding to the two possible spin projections. However, the interaction with the QED vacuum removes this degeneracy, leading to an energy splitting of each level which exceeds the radiative linewidth for low Landau levels if the magnetic field is not too large (B is less than approximately 10 exp 13 G). Estimations are presented of the splitting in various limits as a function of field strength and Landau number. The possibility of observing this splitting in accreting X-ray pulsars and in gamma-ray bursters is discussed.

  6. Hamilton flow generated by field lines near a toroidal magnetic surface

    SciTech Connect

    Skovoroda, A. A.

    2013-07-15

    A method is described for obtaining the Hamiltonian of a vacuum magnetic field in a given 3D toroidal magnetic surface (superconducting shell). This method is used to derive the expression for the integrable surface Hamiltonian in the form of the expansion of a rotational transform of field lines on embedded near-boundary magnetic surfaces into a Taylor series in the distance from the boundary. This expansion contains the value of the rotational transform and its shear at the boundary surface. It is shown that these quantities are related to the components of the first and second quadratic forms of the boundary surface.

  7. Overall view of tower and adjacent aircraft shelters on flight ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Overall view of tower and adjacent aircraft shelters on flight line. View to east. - Plattsburgh Air Force Base, Security Guard Tower, Florida Street at Aircraft Shelters Area, Plattsburgh, Clinton County, NY

  8. Detail exterior view looking north showing piping system adjacent to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail exterior view looking north showing piping system adjacent to engine house. Gas cooling system is on far right. - Burnsville Natural Gas Pumping Station, Saratoga Avenue between Little Kanawha River & C&O Railroad line, Burnsville, Braxton County, WV

  9. Sharp Trapping Boundaries in the Random Walk of Interplanetary Magnetic Field Lines

    NASA Astrophysics Data System (ADS)

    Ruffolo, D.; Chuychai, P.; Meechai, J.; Pongkitiwanichkul, P.; Kimpraphan, N.; Matthaeus, W. H.; Rowlands, G.

    2004-05-01

    Although magnetic field lines in space are believed to undergo a diffusive random walk in the long-distance limit, observed dropouts of solar energetic particles, as well as computer simulations, indicate sharply defined filaments in which interplanetary magnetic field lines have been temporarily trapped. We identify mechanisms that can explain such sharp boundaries in the framework of 2D+slab turbulence, a model that provides a good explanation of solar wind turbulence spectra and the parallel transport of solar energetic particles. Local trapping boundaries (LTBs) are empirically defined as trajectories of 2D turbulence where the mean 2D field is a local maximum. In computer simulations, the filaments (or ``islands'' in the two dimensions perpendicular to the mean field) that are most resistant to slab diffusion correspond closely to the mathematically defined LTBs, that is, there is a mathematical prescription for defining the trapping regions. Furthermore, we provide computational evidence and a theoretical explanation that strong 2D turbulence can inhibit diffusion due to the slab component. Therefore, while these filaments are basically defined by the small-scale topology of 2D turbulence, there can be sharp trapping boundaries where the 2D field is strongest. This work was supported by the Thailand Research Fund, the Rachadapisek Sompoj Fund of Chulalongkorn University, and NASA Grant NAG5-11603. G.R. thanks Mahidol University for its hospitality and the Thailand Commission for Higher Education for travel support.

  10. Field Line Random Walk in Isotropic Magnetic Turbulence up to Infinite Kubo Number

    NASA Astrophysics Data System (ADS)

    Sonsrettee, W.; Wongpan, P.; Ruffolo, D. J.; Matthaeus, W. H.; Chuychai, P.; Rowlands, G.

    2013-12-01

    In astrophysical plasmas, the magnetic field line random walk (FLRW) plays a key role in the transport of energetic particles. In the present, we consider isotropic magnetic turbulence, which is a reasonable model for interstellar space. Theoretical conceptions of the FLRW have been strongly influenced by studies of the limit of weak fluctuations (or a strong mean field) (e.g, Isichenko 1991a, b). In this case, the behavior of FLRW can be characterized by the Kubo number R = (b/B0)(l_∥ /l_ \\bot ) , where l∥ and l_ \\bot are turbulence coherence scales parallel and perpendicular to the mean field, respectively, and b is the root mean squared fluctuation field. In the 2D limit (R ≫ 1), there has been an apparent conflict between concepts of Bohm diffusion, which is based on the Corrsin's independence hypothesis, and percolative diffusion. Here we have used three non-perturbative analytic techniques based on Corrsin's independence hypothesis for B0 = 0 (R = ∞ ): diffusive decorrelation (DD), random ballistic decorrelation (RBD) and a general ordinary differential equation (ODE), and compared them with direct computer simulations. All the analytical models and computer simulations agree that isotropic turbulence for R = ∞ has a field line diffusion coefficient that is consistent with Bohm diffusion. Partially supported by the Thailand Research Fund, NASA, and NSF.

  11. Effects of magnetic fields during high voltage live-line maintenance

    NASA Astrophysics Data System (ADS)

    Göcsei, Gábor; Kiss, István, Dr; Németh, Bálint

    2015-10-01

    In case of transmission and distribution networks, extra low frequency (typically 50 or 60 Hz) electric and magnetic fields have to be taken into consideration separately from each other. Health effects have been documented from exposures to both types of fields. Magnetic fields are qualified as possibly carcinogenic to humans (category “2B”) by WHO's cancer research institute, International Agency for Research on Cancer (IARC), so it is essential to protect the workers against their harmful effects. During live-line maintenance (LLM) electric fields can be shielded effectively by different kinds of conductive clothing, which are enclosed metal surfaces acting as a Faraday-cage. In practice laboratory measurements also prove their efficiency, the required shielding ratio is above 99% by the related standard.. A set of measurements have proved that regular conductive clothing used against the electric fields cannot shield the magnetic fields effectively at all. This paper introduces the possible risks of LLM from the aspect of the health effects of magnetic fields. Although in this case the principle of shielding the electric fields cannot be applied, new considerations in equipment design and technology can be used as a possible solution. Calculations and simulations based on the data of the Hungarian transmission network - which represents the European grid as a part of ENTSO-E - and high-current laboratory measurement results also prove the importance of the topic.

  12. Human perception of electric fields and ion currents associated with high-voltage DC transmission lines.

    PubMed

    Blondin, J P; Nguyen, D H; Sbeghen, J; Goulet, D; Cardinal, C; Maruvada, P S; Plante, M; Bailey, W H

    1996-01-01

    The objective of this study was to assess the ability of humans to detect the presence of DC electric field and ion currents. An exposure chamber simulating conditions present in the vicinity of high-voltage DC (HVDC) lines was designed and built for this purpose. In these experiments, the facility was used to expose observers to DC electric fields up to 50 kV/m and ion current densities up to 120 nA/m2. Forty-eight volunteers (25 women and 23 men) between the ages of 18 and 57 years served as observers. Perception of DC fields was examined by using two psychophysical methods: an adaptive staircase procedure and a rating method derived from signal-detection theory. Subjects completed three different series of observations by using each of these methods; one was conducted without ion currents, and the other two involved various combinations of electric fields and ion currents. Overall, subjects were significantly more likely to detect DC fields as the intensity increased. Observers were able to detect the presence of DC fields alone, but only at high intensities; the average threshold was 45 kV/m. Except in the most sensitive individuals, ion current densities up to 60 nA/m2 did not significantly facilitate the detection of DC fields. However, higher ion current densities were associated with a substantial lowering of sensory thresholds in a large majority of observers. Data analysis also revealed large variations in perceptual thresholds among observers. Normative data indicating DC field and ion current intensities that can be detected by 50% of all observers are provided. In addition, for the most sensitive observers, several other detection proportions were derived from the distribution of individual detection capabilities. These data can form the basis for environmental guidelines relating to the design of HVDC lines.

  13. Shongaloo field: A recent smackover (Jurassic) discovery in the Arkansas-Louisiana state-line graben

    SciTech Connect

    DeMis, W.D.; Milliken, J.V. )

    1993-09-01

    The new North Shongaloo/Red Rock/Haynesville/East Haynesville (herein called Shongaloo) field is a recent discovery (1988) with reserves of 20-30 MMBOE. The field has over 50 wells producing from the Smackover Formation at about 11,000 ft depth, and is the largest field discovered in the very mature Arkansas-Louisiana state-line Smackover play in the past 20 yr. More significantly, the field is locate within the state-line graben, an area considered by industry as barren of Smackover potential because Smackover reservoir rocks were assumed absent. Shongaloo field pay is from the Smackover. The [open quotes]C[close quotes] sand has average porosity of 5-7% and average permeability of less than 1 md (average initial flow rate is 1500 MCFGD with 430 BCPD). The [open quotes]B[close quotes] carbonate reservoirs consist of ooid grainstones with average porosity of 14% and average permeability of 60 md, ranging up to 1800 md (average initial flow rate is 550 BOPD and 950 MCFGD). Shongaloo field is an upthrown fault trap within the overall downthrown central graben. Shongaloo field was found by overcoming two technical hurdles. First, reservoir rock distribution was shown to follow paleoshorelines through the graben. Porous ooid grainstones facies within a mappable cycle of the Smackover [open quotes]B[close quotes] are parallel to, and immediately downdip (<1.5 mi) of paleoshorelines. Paleoshorelines are documented by the updip pinchout of [open quotes]B[close quotes] cycles into time-equivalent Buckner red beds. Second, the critical trapping fault was resolved by shooting and interpreting modern proprietary seismic data. The discovery of Shongaloo field proves that significant reserves can be found in mature domestic plays by applying new technology and stratigraphic concepts.

  14. MODEL OF THE FIELD LINE RANDOM WALK EVOLUTION AND APPROACH TO ASYMPTOTIC DIFFUSION IN MAGNETIC TURBULENCE

    SciTech Connect

    Snodin, A. P.; Ruffolo, D.; Matthaeus, W. H. E-mail: david.ruf@mahidol.ac.th

    2013-01-01

    The turbulent random walk of magnetic field lines plays an important role in the transport of plasmas and energetic particles in a wide variety of astrophysical situations, but most theoretical work has concentrated on determination of the asymptotic field line diffusion coefficient. Here we consider the evolution with distance of the field line random walk using a general ordinary differential equation (ODE), which for most cases of interest in astrophysics describes a transition from free streaming to asymptotic diffusion. By challenging theories of asymptotic diffusion to also describe the evolution, one gains insight on how accurately they describe the random walk process. Previous theoretical work has effectively involved closure of the ODE, often by assuming Corrsin's hypothesis and a Gaussian displacement distribution. Approaches that use quasilinear theory and prescribe the mean squared displacement ({Delta}x {sup 2}) according to free streaming (random ballistic decorrelation, RBD) or asymptotic diffusion (diffusive decorrelation, DD) can match computer simulation results, but only over specific parameter ranges, with no obvious 'marker' of the range of validity. Here we make use of a unified description in which the ODE determines ({Delta}x {sup 2}) self-consistently, providing a natural transition between the assumptions of RBD and DD. We find that the minimum kurtosis of the displacement distribution provides a good indicator of whether the self-consistent ODE is applicable, i.e., inaccuracy of the self-consistent ODE is associated with non-Gaussian displacement distributions.

  15. Near-field focus steering along arbitrary trajectory via multi-lined distributed nanoslits

    PubMed Central

    Lee, Gun-Yeal; Lee, Seung-Yeol; Yun, Hansik; Park, Hyeonsoo; Kim, Joonsoo; Lee, Kyookeun; Lee, Byoungho

    2016-01-01

    The modulation of near-field signals has recently attracted considerable interest because of demands for the development of nano-scale optical devices that are capable of overcoming the diffraction limit of light. In this paper, we propose a new type of tuneable plasmonic lens that permits the foci of surface plasmon polariton (SPP) signals to be continuously steered by adjusting the input polarization state. The proposed structure consists of multi-lined nanoslit arrays, in which each array is tilted at a different angle to provide polarization sensitivity and the nanoslit size is adjusted to balance the relative amplitudes of the excited SPPs from each line. The nanoslits of each line are designed to focus SPPs at different positions; hence, the SPP focal length can be tuned by modifying the incident polarization state. Unlike in previously reported studies, our method enables plasmonic foci to be continuously varied with a smooth change in the incident linear polarization state. The proposed structures provide a novel degree of freedom in the multiplexing of near fields. Such characteristics are expected to enable the realization of active SPP modulation that can be applied in near-field imaging, optical tweezing systems, and integrated nano-devices. PMID:27620281

  16. Near-field focus steering along arbitrary trajectory via multi-lined distributed nanoslits

    NASA Astrophysics Data System (ADS)

    Lee, Gun-Yeal; Lee, Seung-Yeol; Yun, Hansik; Park, Hyeonsoo; Kim, Joonsoo; Lee, Kyookeun; Lee, Byoungho

    2016-09-01

    The modulation of near-field signals has recently attracted considerable interest because of demands for the development of nano-scale optical devices that are capable of overcoming the diffraction limit of light. In this paper, we propose a new type of tuneable plasmonic lens that permits the foci of surface plasmon polariton (SPP) signals to be continuously steered by adjusting the input polarization state. The proposed structure consists of multi-lined nanoslit arrays, in which each array is tilted at a different angle to provide polarization sensitivity and the nanoslit size is adjusted to balance the relative amplitudes of the excited SPPs from each line. The nanoslits of each line are designed to focus SPPs at different positions; hence, the SPP focal length can be tuned by modifying the incident polarization state. Unlike in previously reported studies, our method enables plasmonic foci to be continuously varied with a smooth change in the incident linear polarization state. The proposed structures provide a novel degree of freedom in the multiplexing of near fields. Such characteristics are expected to enable the realization of active SPP modulation that can be applied in near-field imaging, optical tweezing systems, and integrated nano-devices.

  17. Charge-regulation phase transition on surface lattices of titratable sites adjacent to electrolyte solutions: An analog of the Ising antiferromagnet in a magnetic field.

    PubMed

    Shore, Joel D; Thurston, George M

    2015-12-01

    We report a charge-patterning phase transition on two-dimensional square lattices of titratable sites, here regarded as protonation sites, placed in a low-dielectric medium just below the planar interface between this medium and a salt solution. We calculate the work-of-charging matrix of the lattice with use of a linear Debye-Hückel model, as input to a grand-canonical partition function for the distribution of occupancy patterns. For a large range of parameter values, this model exhibits an approximate inverse cubic power-law decrease of the voltage produced by an individual charge, as a function of its in-lattice separation from neighboring titratable sites. Thus, the charge coupling voltage biases the local probabilities of proton binding as a function of the occupancy of sites for many neighbors beyond the nearest ones. We find that even in the presence of these longer-range interactions, the site couplings give rise to a phase transition in which the site occupancies exhibit an alternating, checkerboard pattern that is an analog of antiferromagnetic ordering. The overall strength W of this canonical charge coupling voltage, per unit charge, is a function of the Debye length, the charge depth, the Bjerrum length, and the dielectric coefficients of the medium and the solvent. The alternating occupancy transition occurs above a curve of thermodynamic critical points in the (pH-pK,W) plane, the curve representing a charge-regulation analog of variation of the Néel temperature of an Ising antiferromagnet as a function of an applied, uniform magnetic field. The analog of a uniform magnetic field in the antiferromagnet problem is a combination of pH-pK and W, and 1/W is the analog of the temperature in the antiferromagnet problem. We use Monte Carlo simulations to study the occupancy patterns of the titratable sites, including interactions out to the 37th nearest-neighbor category (a distance of √74 lattice constants), first validating simulations through

  18. Charge-regulation phase transition on surface lattices of titratable sites adjacent to electrolyte solutions: An analog of the Ising antiferromagnet in a magnetic field

    NASA Astrophysics Data System (ADS)

    Shore, Joel D.; Thurston, George M.

    2015-12-01

    We report a charge-patterning phase transition on two-dimensional square lattices of titratable sites, here regarded as protonation sites, placed in a low-dielectric medium just below the planar interface between this medium and a salt solution. We calculate the work-of-charging matrix of the lattice with use of a linear Debye-Hückel model, as input to a grand-canonical partition function for the distribution of occupancy patterns. For a large range of parameter values, this model exhibits an approximate inverse cubic power-law decrease of the voltage produced by an individual charge, as a function of its in-lattice separation from neighboring titratable sites. Thus, the charge coupling voltage biases the local probabilities of proton binding as a function of the occupancy of sites for many neighbors beyond the nearest ones. We find that even in the presence of these longer-range interactions, the site couplings give rise to a phase transition in which the site occupancies exhibit an alternating, checkerboard pattern that is an analog of antiferromagnetic ordering. The overall strength W of this canonical charge coupling voltage, per unit charge, is a function of the Debye length, the charge depth, the Bjerrum length, and the dielectric coefficients of the medium and the solvent. The alternating occupancy transition occurs above a curve of thermodynamic critical points in the (p H-p K ,W ) plane, the curve representing a charge-regulation analog of variation of the Néel temperature of an Ising antiferromagnet as a function of an applied, uniform magnetic field. The analog of a uniform magnetic field in the antiferromagnet problem is a combination of p H-p K and W , and 1 /W is the analog of the temperature in the antiferromagnet problem. We use Monte Carlo simulations to study the occupancy patterns of the titratable sites, including interactions out to the 37th nearest-neighbor category (a distance of √{74 } lattice constants), first validating simulations

  19. Magnetic Field Line Tracing Calculations for Conceptual PFC Design in the National Compact Stellarator Experiment

    SciTech Connect

    Maingi, R; Kaiser, T; Hill, D N; Lyon, J F; Monticello, D; Zarnstorff, M C

    2006-06-12

    The National Compact Stellarator Experiment (NCSX) is a three-field period compact stellarator presently in the construction phase at Princeton, NJ. The design parameters of the device are major radius R=1.4m, average minor radius = 0.32m, 1.2 {le} toroidal field (B{sub t}) {le} 1.7 T, and auxiliary input power up to 12 MW with neutral beams and radio-frequency heating. The NCSX average aspect ratio of 4.4 lies well below present stellarator experiments and designs, enabling the investigation of high {beta} physics in a compact stellarator geometry. Also the NCSX design choice for a quasi-axisymmetric configuration aims toward the achievement of tokamak-like transport. In this paper, we report on the magnetic field line tracing calculations used to evaluate conceptual plasma facing component (PFC) designs. In contrast to tokamaks, axisymmetric target plates are not required to intercept the majority of the heat flux in stellarators, owing to the nature of the 3-D magnetic field footprint. The divertor plate design investigated in this study covers approximately one half of the toroidal extent in each period. Typical Poincare plots in Figure 1 illustrate the plasma cross-section at several toroidal angles for a computed NCSX high-beta equilibrium. The plates used for these calculations are centered in each period about the elongated cross-section shown in Figure 1a, extending to +/- {pi}/6 in each direction. Two methods for tracing the edge field line topology were used in this study. The first entails use of the VMEC/MFBE-2001 packages, whereas the second entails use of the PIES code with a post-processor by Michael Drevlak; the same field line integration routine was used to evaluate the equilibria for this comparison. Both inputs were generated based on the {beta}=4%, =iota=0.5 equilibrium computed from the final NCSX coil set. We first compare these two methods for a specific plate geometry, and conclude with a comparison of the strike characteristics

  20. The field line map approach for simulations of magnetically confined plasmas

    NASA Astrophysics Data System (ADS)

    Stegmeir, Andreas; Coster, David; Maj, Omar; Hallatschek, Klaus; Lackner, Karl

    2016-01-01

    Predictions of plasma parameters in the edge and scrape-off layer of tokamaks is difficult since most modern tokamaks have a divertor and the associated separatrix causes the usually employed field/flux-aligned coordinates to become singular on the separatrix/X-point. The presented field line map approach avoids such problems as it is based on a cylindrical grid: standard finite-difference methods can be used for the discretisation of perpendicular (w.r.t. magnetic field) operators, and the characteristic flute mode property (k∥ ≪k⊥) of structures is exploited computationally via a field line following discretisation of parallel operators which leads to grid sparsification in the toroidal direction. This paper is devoted to the discretisation of the parallel diffusion operator (the approach taken is very similar to the flux-coordinate independent (FCI) approach which has already been adopted to a hyperbolic problem (Ottaviani, 2011; Hariri, 2013)). Based on the support operator method, schemes are derived which maintain the self-adjointness property of the parallel diffusion operator on the discrete level. These methods have very low numerical perpendicular diffusion compared to a naive discretisation which is a critical issue since magnetically confined plasmas exhibit a very strong anisotropy. Two different versions of the discrete parallel diffusion operator are derived: the first is based on interpolation where the order of interpolation and therefore the numerical diffusion is adjustable; the second is based on integration and is advantageous in cases where the field line map is strongly distorted. The schemes are implemented in the new code GRILLIX, and extensive benchmarks and numerous examples are presented which show the validity of the approach in general and GRILLIX in particular.

  1. Does soil water saturation mobilize metals from riparian soils to adjacent surface water? A field monitoring study in a metal contaminated region.

    PubMed

    Van Laer, Liesbeth; Smolders, Erik

    2013-06-01

    In the Noorderkempen (NW Belgium), a large area (about 280 km(2)) is contaminated with cadmium (Cd) and zinc (Zn) due to historical pollution by the Zn smelters. Direct aquatic emissions of metals have diminished over time, however the surface water metal concentration largely exceeds quality standards, mainly during winter periods. Monitoring data were analyzed to reveal whether these fluctuations are related to seasonal redox reactions in associated contaminated riparian soils that drain into the rivers. A field survey was set up with soil pore-water and groundwater monitored for three years in transects of soil monitoring points perpendicular to rivers at contaminated and non-contaminated sites. Site averaged surface water concentrations of a 15 year dataset exceeded local quality standards 4 to 200-fold. Winter averaged metal concentrations significantly exceeded the corresponding summer values 1.3-1.8 (Zn) and 1.5-2.4 fold (Cd). Zinc and Cd concentrations in water were positively related to Fe and Mn but not to Ca, K or Na suggesting that redox reactions and not dilution processes are involved. In ground- and pore-water of the associated riparian soils, the concentrations of Zn fluctuate by the same order of magnitude as in surface water but were generally smaller than in the corresponding contaminated rivers. In addition, correlations of dissolved Zn with Fe and Mn were lacking. This analysis suggests that redox reactions in streams, and not in riparian soils, explain the seasonal trends of Zn and Cd in surface water. Hence, river sediments and not riparian soils may be the cause of the winter peaks of Zn and Cd in these rivers.

  2. Empirical Predictions for (Sub-)millimeter Line and Continuum Deep Fields

    NASA Astrophysics Data System (ADS)

    da Cunha, Elisabete; Walter, Fabian; Decarli, Roberto; Bertoldi, Frank; Carilli, Chris; Daddi, Emanuele; Elbaz, David; Ivison, Rob; Maiolino, Roberto; Riechers, Dominik; Rix, Hans-Walter; Sargent, Mark; Smail, Ian; Weiss, Axel

    2013-03-01

    Modern (sub-)millimeter/radio interferometers such as ALMA, JVLA, and the PdBI successor NOEMA will enable us to measure the dust and molecular gas emission from galaxies that have luminosities lower than the Milky Way, out to high redshifts and with unprecedented spatial resolution and sensitivity. This will provide new constraints on the star formation properties and gas reservoir in galaxies throughout cosmic times through dedicated deep field campaigns targeting the CO/[C II] lines and dust continuum emission in the (sub-)millimeter regime. In this paper, we present empirical predictions for such line and continuum deep fields. We base these predictions on the deepest available optical/near-infrared Advanced Camera for Surveys and NICMOS data on the Hubble Ultra Deep Field (over an area of about 12 arcmin2). Using a physically motivated spectral energy distribution model, we fit the observed optical/near-infrared emission of 13,099 galaxies with redshifts up to z = 5, and obtain median-likelihood estimates of their stellar mass, star formation rate, dust attenuation, and dust luminosity. We combine the attenuated stellar spectra with a library of infrared emission models spanning a wide range of dust temperatures to derive statistical constraints on the dust emission in the infrared and (sub-)millimeter which are consistent with the observed optical/near-infrared emission in terms of energy balance. This allows us to estimate, for each galaxy, the (sub-)millimeter continuum flux densities in several ALMA, PdBI/NOEMA, and JVLA bands. As a consistency check, we verify that the 850 μm number counts and extragalactic background light derived using our predictions are consistent with previous observations. Using empirical relations between the observed CO/[C II] line luminosities and the infrared luminosity of star-forming galaxies, we infer the luminosity of the CO(1-0) and [C II] lines from the estimated infrared luminosity of each galaxy in our sample. We then

  3. Simulation investigation of a Ku-band radial line oscillator operating at low guiding magnetic field

    SciTech Connect

    Dang, Fangchao Zhang, Xiaoping; Zhong, Huihuang; Li, Yangmei; Qi, Zumin

    2014-06-15

    A novel radial line oscillator operating at Ku-band with low guiding magnetic field is proposed in this paper. By using an oversized radial structure, the power handling capacity is enhanced significantly. Based on the small-signal theory, the π/2 mode in radial TM{sub 01} mode is selected as the working mode. Furthermore, a radial uniform guiding magnetic field, made up of four solenoids, is designed. As indicated in 2.5-dimensional fully electromagnetic particle-in-cell simulation, high power microwaves with a power of 2.2 GW and a frequency of 14.25 GHz are generated with over 40% efficiency when the electron beam voltage is 300 kV, the beam current 18 kA, and the guiding magnetic field is only 0.6 T. There is no angular non-asymmetric mode discovered in three-dimensional simulation.

  4. Drifts, boundary conditions and plasma convection on open magnetic field lines

    SciTech Connect

    Cohen, R. H.

    1998-11-20

    In a number of plasmas of practical interest, including the scrape-off layer of a tokamak with a divertor or toroidal limiter, some gas discharge devices, and in the vicinity of spacecraft, magnetic field lines intersect bounding surfaces at shallow angles. Under these circumstances a number of interesting and important effects arise. Drifts can compete with parallel flows in establishing the boundary conditions for plasma mass-flow and current (sheath current-voltage characteristics). We derive the mass-flow constraints including both poloidal and radial drifts, review the current boundary conditions, and survey the consequences, including along-field density and heat-flux asymmetries, convection created by a wavy surface, generation of electric fields and surface currents associated with shadows from surface structures, and modification of instability growth.

  5. Simulation investigation of a Ku-band radial line oscillator operating at low guiding magnetic field

    NASA Astrophysics Data System (ADS)

    Dang, Fangchao; Zhang, Xiaoping; Zhong, Huihuang; Li, Yangmei; Qi, Zumin

    2014-06-01

    A novel radial line oscillator operating at Ku-band with low guiding magnetic field is proposed in this paper. By using an oversized radial structure, the power handling capacity is enhanced significantly. Based on the small-signal theory, the π/2 mode in radial TM01 mode is selected as the working mode. Furthermore, a radial uniform guiding magnetic field, made up of four solenoids, is designed. As indicated in 2.5-dimensional fully electromagnetic particle-in-cell simulation, high power microwaves with a power of 2.2 GW and a frequency of 14.25 GHz are generated with over 40% efficiency when the electron beam voltage is 300 kV, the beam current 18 kA, and the guiding magnetic field is only 0.6 T. There is no angular non-asymmetric mode discovered in three-dimensional simulation.

  6. Spectral response of atmospheric electric field measurements near AC high voltage power lines

    NASA Astrophysics Data System (ADS)

    Silva, H. G.; Matthews, J. C.; Wright, M. D.; Shallcross, D. E.

    2015-10-01

    To understand the influence of corona ion emission on the atmospheric electrical field, measurements were made near to two AC high voltage power lines. A JCI 131 field-mill recorded the atmospheric electric field over one year. Meteorological measurements were also taken. The data series is divided in four zones (dependent on wind direction): whole zones, Z0; zone 1, Z1; zone 2, Z2; zone 3, Z3. Z3 is the least affected by corona ion emission and for that reason it is used as a reference against Z1 and Z2, which are strongly influenced by this phenomena. Analysis was undertaken for all weather days and dry days only. The Lomb-Scargle strategy developed for unevenly spaced time-series is used to calculate the spectral response of the aforementioned zones. Only frequencies above 1 minute are considered.

  7. Field trials of line transect methods applied to estimation of desert tortoise abundance

    USGS Publications Warehouse

    Anderson, David R.; Burnham, Kenneth P.; Lubow, Bruce C.; Thomas, L. E. N.; Corn, Paul Stephen; Medica, Philip A.; Marlow, R.W.

    2001-01-01

    We examine the degree to which field observers can meet the assumptions underlying line transect sampling to monitor populations of desert tortoises (Gopherus agassizii). We present the results of 2 field trials using artificial tortoise models in 3 size classes. The trials were conducted on 2 occasions on an area south of Las Vegas, Nevada, where the density of the test population was known. In the first trials, conducted largely by experienced biologists who had been involved in tortoise surveys for many years, the density of adult tortoise models was well estimated (-3.9% bias), while the bias was higher (-20%) for subadult tortoise models. The bias for combined data was -12.0%. The bias was largely attributed to the failure to detect all tortoise models on or near the transect centerline. The second trials were conducted with a group of largely inexperienced student volunteers and used somewhat different searching methods, and the results were similar to the first trials. Estimated combined density of subadult and adult tortoise models had a negative bias (-7.3%), again attributable to failure to detect some models on or near the centerline. Experience in desert tortoise biology, either comparing the first and second trials or in the second trial with 2 experienced biologists versus 16 novices, did not have an apparent effect on the quality of the data or the accuracy of the estimates. Observer training, specific to line transect sampling, and field testing are important components of a reliable survey. Line transect sampling represents a viable method for large-scale monitoring of populations of desert tortoise; however, field protocol must be improved to assure the key assumptions are met.

  8. Observations of Field Line Resonances by Low-Altitude ST-5 Satellites

    NASA Technical Reports Server (NTRS)

    Le, G.; Chi, P. J.; Strangeway, R. J.; Slavin, J. A.

    2010-01-01

    Space Technology 5 (ST-5) mission is a three micro-satellite constellation deployed into a 300 x 4500 km, dawn-dusk, and sun synchronous polar orbit with 105.6deg inclination angle. Due to the Earth's rotation and the dipole tilt effect, the spacecraft's dawn-dusk orbit track can reach as low as subauroral latitudes during the course of a day. Whenever the spacecraft traverse across the dayside closed field line region at subauroral latitudes, they frequently observe strong transverse oscillations at 30-200 mHz, or in the Pe 2-3 frequency range. These Pc 2-3 waves appear as wave packets with durations in the order of 5-10 minutes. As the maximum separations of the ST-5 spacecraft are in the order of 10 minutes, the three ST-5 satellites often observe very similar wave packets, implying these wave oscillations occur in a localized region. The coordinated ground-based magnetic observations at the spacecraft footprints, however, do not see waves in the Pc 2- 3 band; instead, the waves appear to be the common Pc 4-5 waves associated with field line resonances. We suggest that this unique Pc 2-3 waves seen by ST-5 are in fact the Doppler-shifted Pc 4-5 waves as a result of rapid traverse of the spacecraft across the resonant field lines azimuthally at low altitudes. The observations with the unique spacecraft dawn-disk orbits at proper altitudes and magnetic latitudes reveal the azimuthal characteristics of field-aligned resonances.

  9. Bias-field controlled phasing and power combination of gyromagnetic nonlinear transmission lines.

    PubMed

    Reale, D V; Bragg, J-W B; Gonsalves, N R; Johnson, J M; Neuber, A A; Dickens, J C; Mankowski, J J

    2014-05-01

    Gyromagnetic Nonlinear Transmission Lines (NLTLs) generate microwaves through the damped gyromagnetic precession of the magnetic moments in ferrimagnetic material, and are thus utilized as compact, solid-state, frequency agile, high power microwave (HPM) sources. The output frequency of a NLTL can be adjusted by control of the externally applied bias field and incident voltage pulse without physical alteration to the structure of the device. This property provides a frequency tuning capability not seen in many conventional e-beam based HPM sources. The NLTLs developed and tested are mesoband sources capable of generating MW power levels in the L, S, and C bands of the microwave spectrum. For an individual NLTL the output power at a given frequency is determined by several factors including the intrinsic properties of the ferrimagnetic material and the transmission line structure. Hence, if higher power levels are to be achieved, it is necessary to combine the outputs of multiple NLTLs. This can be accomplished in free space using antennas or in a transmission line via a power combiner. Using a bias-field controlled delay, a transient, high voltage, coaxial, three port, power combiner was designed and tested. Experimental results are compared with the results of a transient COMSOL simulation to evaluate combiner performance.

  10. Bias-field controlled phasing and power combination of gyromagnetic nonlinear transmission lines

    SciTech Connect

    Reale, D. V. Bragg, J.-W. B.; Gonsalves, N. R.; Johnson, J. M.; Neuber, A. A.; Dickens, J. C.; Mankowski, J. J.

    2014-05-15

    Gyromagnetic Nonlinear Transmission Lines (NLTLs) generate microwaves through the damped gyromagnetic precession of the magnetic moments in ferrimagnetic material, and are thus utilized as compact, solid-state, frequency agile, high power microwave (HPM) sources. The output frequency of a NLTL can be adjusted by control of the externally applied bias field and incident voltage pulse without physical alteration to the structure of the device. This property provides a frequency tuning capability not seen in many conventional e-beam based HPM sources. The NLTLs developed and tested are mesoband sources capable of generating MW power levels in the L, S, and C bands of the microwave spectrum. For an individual NLTL the output power at a given frequency is determined by several factors including the intrinsic properties of the ferrimagnetic material and the transmission line structure. Hence, if higher power levels are to be achieved, it is necessary to combine the outputs of multiple NLTLs. This can be accomplished in free space using antennas or in a transmission line via a power combiner. Using a bias-field controlled delay, a transient, high voltage, coaxial, three port, power combiner was designed and tested. Experimental results are compared with the results of a transient COMSOL simulation to evaluate combiner performance.

  11. Wide-Field Emission-Line Imaging of Galactic Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Winkler, P. Frank; Smith, R. Chris

    2001-02-01

    We propose to complete narrow-band emission-line imaging of all the southern supernova remnants (SNRs) for which optical emission has been reported. The great majority of these have never been systematically studied using CCDs. Images in Hα, S II, and O III will enable us to distinguish shock-heated SNR filaments from photo-ionized nebulosity and to search for rare, ejecta-dominated filaments. With matched continuum images we will subtract the stars to give pure emission-line images and reveal faint diffuse features. The results will be used in conjunction with X-ray and radio images for multi-wavelength studies of SNRs and the ISM. We plan to assemble an emission-line atlas of SNRs, to be available in both published form and on-line as digital images. This study requires the unique wide field and fast beam of the Schmidt, so we request sufficient time to complete it in the last semester of this instrument's availability. In addition, we plan deep, broad-band imaging of the SN 1006 remnant in attempt at the first measurement of optical synchrotron emission behind an SNR shock. Detection at the level expected from extrapolation of radio and X-ray power-law spectra would support the picture that Fermi acceleration of electrons to TeV energies produces both X-ray emission and cosmic rays, while significant upper limits would raise questions about this picture.

  12. Line-patterning of polyaniline coated MWCNT on stepped substrates using DC electric field

    PubMed Central

    Ko, Young Gun; Do, Tae Gu; Oh, Hyun Chul; Lee, Hyun Jeong; Han, Hung-gu; Kim, Choong Hyun; Choi, Ung Su

    2014-01-01

    Printing electronic components on a chip edge and a stepped substrate with functional inks are an attractive approach for achieving flexible and inexpensive circuits for applications such as flexible displays and large-area chemo/bio/radioactivity sensors. However, it is still challenging because a sufficient cover of the 100 μm high step at the chip edge with a high-resolution pattern is the hardest part of the layer assembling by inkjet printing. Herein, we present a simple and effective strategy to generate electrically conductive line-patterns on stepped substrates by applying the DC electric field. On the surface of flat polyimide substrate, the fine line-pattern (less than 850 nm in line width) is achieved with a polyaniline coated MWCNT dispersed ink. Furthermore, 9.9 μm of line width is successfully patterned on the high stepped poly(dimethylsiloxane) substrate, higher than 100 μm, by printing only 1 time. PMID:25325776

  13. Effect of transverse magnetic fields on a simulated in-line 6 MV linac

    NASA Astrophysics Data System (ADS)

    St. Aubin, J.; Steciw, S.; Fallone, B. G.

    2010-08-01

    The effects of a transverse magnetic field on an in-line side-coupled 6 MV linear accelerator are given. The results are directly applicable to a linac-MR system used for real-time image guided adaptive radiotherapy. Our previously designed end-to-end linac simulation incorporated the results from the axisymmetric 2D electron gun program EGN2w. However, since the magnetic fields being investigated are non-axisymmetric in nature for the work presented here, the electron gun simulation was performed using OPERA-3d/SCALA. The simulation results from OPERA-3d/SCALA showed excellent agreement with previous results. Upon the addition of external magnetic fields to our fully 3D linac simulation, it was found that a transverse magnetic field of 6 G resulted in a 45 ± 1% beam loss, and by 14 G, no electrons were incident on the target. Transverse magnetic fields on the linac simulation produced a highly asymmetric focal spot at the target, which translated into a 13% profile asymmetry at 6 G. Upon translating the focal spot with respect to the target coordinates, profile symmetry was regained at the expense of a lateral shift in the dose profiles. It was found that all points in the penumbra failed a 1%/1 mm acceptance criterion for fields between 4 and 6 G. However, it was also found that the lateral profile shifts were corrected by adjusting the jaw positions asymmetrically.

  14. Effects of external radiation fields on line emission—application to star-forming regions

    SciTech Connect

    Chatzikos, Marios; Ferland, G. J.; Williams, R. J. R.; Porter, Ryan; Van Hoof, P. A. M.

    2013-12-20

    A variety of astronomical environments contain clouds irradiated by a combination of isotropic and beamed radiation fields. For example, molecular clouds may be irradiated by the isotropic cosmic microwave background, as well as by a nearby active galactic nucleus. These radiation fields excite atoms and molecules and produce emission in different ways. We revisit the escape probability theorem and derive a novel expression that accounts for the presence of external radiation fields. We show that when the field is isotropic the escape probability is reduced relative to that in the absence of external radiation. This is in agreement with previous results obtained under ad hoc assumptions or with the two-level system, but can be applied to complex many-level models of atoms or molecules. This treatment is in the development version of the spectral synthesis code CLOUDY. We examine the spectrum of a Spitzer cloud embedded in the local interstellar radiation field and show that about 60% of its emission lines are sensitive to background subtraction. We argue that this geometric approach could provide an additional tool toward understanding the complex radiation fields of starburst galaxies.

  15. DIRECT OBSERVATION OF SOLAR CORONAL MAGNETIC FIELDS BY VECTOR TOMOGRAPHY OF THE CORONAL EMISSION LINE POLARIZATIONS

    SciTech Connect

    Kramar, M.; Lin, H.; Tomczyk, S. E-mail: lin@ifa.hawaii.edu

    2016-03-10

    We present the first direct “observation” of the global-scale, 3D coronal magnetic fields of Carrington Rotation (CR) Cycle 2112 using vector tomographic inversion techniques. The vector tomographic inversion uses measurements of the Fe xiii 10747 Å Hanle effect polarization signals by the Coronal Multichannel Polarimeter (CoMP) and 3D coronal density and temperature derived from scalar tomographic inversion of Solar Terrestrial Relations Observatory (STEREO)/Extreme Ultraviolet Imager (EUVI) coronal emission lines (CELs) intensity images as inputs to derive a coronal magnetic field model that best reproduces the observed polarization signals. While independent verifications of the vector tomography results cannot be performed, we compared the tomography inverted coronal magnetic fields with those constructed by magnetohydrodynamic (MHD) simulations based on observed photospheric magnetic fields of CR 2112 and 2113. We found that the MHD model for CR 2112 is qualitatively consistent with the tomography inverted result for most of the reconstruction domain except for several regions. Particularly, for one of the most noticeable regions, we found that the MHD simulation for CR 2113 predicted a model that more closely resembles the vector tomography inverted magnetic fields. In another case, our tomographic reconstruction predicted an open magnetic field at a region where a coronal hole can be seen directly from a STEREO-B/EUVI image. We discuss the utilities and limitations of the tomographic inversion technique, and present ideas for future developments.

  16. ¹⁴N Quadrupole Resonance line broadening due to the earth magnetic field, occuring only in the case of an axially symmetric electric field gradient tensor.

    PubMed

    Aissani, Sarra; Guendouz, Laouès; Marande, Pierre-Louis; Canet, Daniel

    2015-01-01

    As demonstrated before, the application of a weak static B0 magnetic field (less than 10 G) may produce definite effects on the ¹⁴N Quadrupole Resonance line when the electric field gradient tensor at the nitrogen nucleus level is of axial symmetry. Here, we address more precisely the problem of the relative orientation of the two magnetic fields (the static field and the radio-frequency field of the pure NQR experiment). For a field of 6G, the evolution of the signal intensity, as a function of this relative orientation, is in very good agreement with the theoretical predictions. There is in particular an intensity loss by a factor of three when going from the parallel configuration to the perpendicular configuration. By contrast, when dealing with a very weak magnetic field (as the earth field, around 0.5 G), this effect drops to ca. 1.5 in the case Hexamethylenetetramine (HMT).This is explained by the fact that the Zeeman shift (due to the very weak magnetic field) becomes comparable to the natural line-width. The latter can therefore be determined by accounting for this competition. Still in the case of HMT, the estimated natural line-width is half the observed line-width. The extra broadening is thus attributed to earth magnetic field. The latter constitutes therefore the main cause of the difference between the natural transverse relaxation time (T₂) and the transverse relaxation time derived from the observed line-width (T₂(⁎)).

  17. Wave-particle interaction in parallel transport of long mean-free-path plasmas along open field magnetic field lines

    NASA Astrophysics Data System (ADS)

    Guo, Zehua; Tang, Xianzhu

    2012-03-01

    A tokamak fusion reactor dumps a large amount of heat and particle flux to the divertor through the scrape-off plasma (SOL). Situation exists either by necessity or through deliberate design that the SOL plasma attains long mean-free-path along large segments of the open field lines. The rapid parallel streaming of electrons requires a large parallel electric field to maintain ambipolarity. The confining effect of the parallel electric field on electrons leads to a trap/passing boundary in the velocity space for electrons. In the normal situation where the upstream electron source populates both the trapped and passing region, a mechanism must exist to produce a flux across the electron trap/passing boundary. In a short mean-free-path plasma, this is provided by collisions. For long mean-free-path plasmas, wave-particle interaction is the primary candidate for detrapping the electrons. Here we present simulation results and a theoretical analysis using a model distribution function of trapped electrons. The dominating electromagnetic plasma instability and the associated collisionless scattering, that produces both particle and energy fluxes across the electron trap/passing boundary in velocity space, are discussed.

  18. Non-contact single shot elastography using line field low coherence holography

    PubMed Central

    Liu, Chih-Hao; Schill, Alexander; Wu, Chen; Singh, Manmohan; Larin, Kirill V.

    2016-01-01

    Optical elastic wave imaging is a powerful technique that can quantify local biomechanical properties of tissues. However, typically long acquisition times make this technique unfeasible for clinical use. Here, we demonstrate non-contact single shot elastographic holography using a line-field interferometer integrated with an air-pulse delivery system. The propagation of the air-pulse induced elastic wave was imaged in real time, and required a single excitation for a line-scan measurement. Results on tissue-mimicking phantoms and chicken breast muscle demonstrated the feasibility of this technique for accurate assessment of tissue biomechanical properties with an acquisition time of a few milliseconds using parallel acquisition. PMID:27570694

  19. Ultra-fast line-field low coherence holographic elastography using spatial phase shifting.

    PubMed

    Liu, Chih-Hao; Schill, Alexander; Raghunathan, Raksha; Wu, Chen; Singh, Manmohan; Han, Zhaolong; Nair, Achuth; Larin, Kirill V

    2017-02-01

    Optical coherence elastography (OCE) is an emerging technique for quantifying tissue biomechanical properties. Generally, OCE relies on point-by-point scanning. However, long acquisition times make point-by-point scanning unfeasible for clinical use. Here we demonstrate a noncontact single shot line-field low coherence holography system utilizing an automatic Hilbert transform analysis based on a spatial phase shifting technique. Spatio-temporal maps of elastic wave propagation were acquired with only one air-pulse excitation and used to quantify wave velocity and sample mechanical properties at a line rate of 200 kHz. Results obtained on phantoms were correlated with data from mechanical testing. Finally, the stiffness of porcine cornea at different intraocular pressures was also quantified in situ.

  20. Ultra-fast line-field low coherence holographic elastography using spatial phase shifting

    PubMed Central

    Liu, Chih-Hao; Schill, Alexander; Raghunathan, Raksha; Wu, Chen; Singh, Manmohan; Han, Zhaolong; Nair, Achuth; Larin, Kirill V.

    2017-01-01

    Optical coherence elastography (OCE) is an emerging technique for quantifying tissue biomechanical properties. Generally, OCE relies on point-by-point scanning. However, long acquisition times make point-by-point scanning unfeasible for clinical use. Here we demonstrate a noncontact single shot line-field low coherence holography system utilizing an automatic Hilbert transform analysis based on a spatial phase shifting technique. Spatio-temporal maps of elastic wave propagation were acquired with only one air-pulse excitation and used to quantify wave velocity and sample mechanical properties at a line rate of 200 kHz. Results obtained on phantoms were correlated with data from mechanical testing. Finally, the stiffness of porcine cornea at different intraocular pressures was also quantified in situ. PMID:28270998

  1. Line-field parallel swept source MHz OCT for structural and functional retinal imaging.

    PubMed

    Fechtig, Daniel J; Grajciar, Branislav; Schmoll, Tilman; Blatter, Cedric; Werkmeister, Rene M; Drexler, Wolfgang; Leitgeb, Rainer A

    2015-03-01

    We demonstrate three-dimensional structural and functional retinal imaging with line-field parallel swept source imaging (LPSI) at acquisition speeds of up to 1 MHz equivalent A-scan rate with sensitivity better than 93.5 dB at a central wavelength of 840 nm. The results demonstrate competitive sensitivity, speed, image contrast and penetration depth when compared to conventional point scanning OCT. LPSI allows high-speed retinal imaging of function and morphology with commercially available components. We further demonstrate a method that mitigates the effect of the lateral Gaussian intensity distribution across the line focus and demonstrate and discuss the feasibility of high-speed optical angiography for visualization of the retinal microcirculation.

  2. Line-field parallel swept source MHz OCT for structural and functional retinal imaging

    PubMed Central

    Fechtig, Daniel J.; Grajciar, Branislav; Schmoll, Tilman; Blatter, Cedric; Werkmeister, Rene M.; Drexler, Wolfgang; Leitgeb, Rainer A.

    2015-01-01

    We demonstrate three-dimensional structural and functional retinal imaging with line-field parallel swept source imaging (LPSI) at acquisition speeds of up to 1 MHz equivalent A-scan rate with sensitivity better than 93.5 dB at a central wavelength of 840 nm. The results demonstrate competitive sensitivity, speed, image contrast and penetration depth when compared to conventional point scanning OCT. LPSI allows high-speed retinal imaging of function and morphology with commercially available components. We further demonstrate a method that mitigates the effect of the lateral Gaussian intensity distribution across the line focus and demonstrate and discuss the feasibility of high-speed optical angiography for visualization of the retinal microcirculation. PMID:25798298

  3. An asymptotic preserving method for strongly anisotropic diffusion equations based on field line integration

    NASA Astrophysics Data System (ADS)

    Tang, Min; Wang, Yihong

    2017-02-01

    In magnetized plasma, the magnetic field confines the particles around the field lines. The anisotropy intensity in the viscosity and heat conduction may reach the order of 1012. When the boundary conditions are periodic or Neumann, the strong diffusion leads to an ill-posed limiting problem. To remove the ill-conditionedness in the highly anisotropic diffusion equations, we introduce a simple but very efficient asymptotic preserving reformulation in this paper. The key idea is that, instead of discretizing the Neumann boundary conditions locally, we replace one of the Neumann boundary condition by the integration of the original problem along the field line, the singular 1 / ɛ terms can be replaced by O (1) terms after the integration, which yields a well-posed problem. Small modifications to the original code are required and no change of coordinates nor mesh adaptation are needed. Uniform convergence with respect to the anisotropy strength 1 / ɛ can be observed numerically and the condition number does not scale with the anisotropy.

  4. Retinal photoreceptor imaging with high-speed line-field parallel spectral domain OCT (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Ginner, Laurin; Fechtig, Daniel J.; Schmoll, Tilman; Wurster, Lara M.; Pircher, Michael; Leitgeb, Rainer A.; Drexler, Wolfgang

    2016-03-01

    We present retinal photoreceptor imaging with a line-field parallel spectral domain OCT modality, utilizing a commercially available 2D CMOS detector array operating at and imaging speed of 500 B-scans/s. Our results demonstrate for the first time in vivo structural and functional retinal assessment with a line-field OCT setup providing sufficient sensitivity, lateral and axial resolution and 3D acquisition rates in order to resolve individual photoreceptor cells. The setup comprises a Michelson interferometer illuminated by a broadband light source, where a line-focus is formed via a cylindrical lens and the back-propagated light from sample and reference arm is detected by a 2D array after passing a diffraction grating. The spot size of the line-focus on the retina is 5μm, which corresponds to a PSF of 50μm and an oversampling factor of 3.6 at the detector plane, respectively. A full 3D stack was recorded in only 0.8 s. We show representative enface images, tomograms and phase-difference maps of cone photoreceptors with a lateral FOV close to 2°. The high-speed capability and the phase stability due to parallel illumination and detection may potentially lead to novel structural and functional diagnostic tools on a cellular and microvascular imaging level. Furthermore, the presented system enables competitive imaging results as compared to respective point scanning modalities and facilitates utilizing software based digital aberration correction algorithms for achieving 3D isotropic resolution across the full FOV.

  5. Retinal photoreceptor imaging with high-speed line-field parallel spectral domain OCT (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Fechtig, Daniel J.; Ginner, Laurin; Kumar, Abhishek; Pircher, Michael; Schmoll, Tilman; Wurster, Lara M.; Drexler, Wolfgang; Leitgeb, Rainer A.

    2016-03-01

    We present retinal photoreceptor imaging with a line-field parallel spectral domain OCT modality, utilizing a commercially available 2D CMOS detector array operating at and imaging speed of 500 B-scans/s. Our results demonstrate for the first time in vivo structural and functional retinal assessment with a line-field OCT setup providing sufficient sensitivity, lateral and axial resolution and 3D acquisition rates in order to resolve individual photoreceptor cells. The phase stability of the system is manifested by the high phase-correlation across the lateral FOV on the level of individual photoreceptors. The setup comprises a Michelson interferometer illuminated by a broadband light source, where a line-focus is formed via a cylindrical lens and the back-propagated light from sample and reference arm is detected by a 2D array after passing a diffraction grating. The spot size of the line-focus on the retina is 5μm, which corresponds to a PSF of 50μm and an oversampling factor of 3.6 at the detector plane, respectively. A full 3D stack was recorded in only 0.8 s. We show representative enface images, tomograms and phase-difference maps of cone photoreceptors with a lateral FOV close to 2°. The high-speed capability and the phase stability due to parallel illumination and detection may potentially lead to novel structural and functional diagnostic tools on a cellular and microvascular imaging level. Furthermore, the presented system enables competitive imaging results as compared to respective point scanning modalities and facilitates utilizing software based digital aberration correction algorithms for achieving 3D isotropic resolution across the full FOV.

  6. Studies of Dynamic, Radiative Macroscopic Magnetized HED Plasmas with Closed B-Field Lines

    SciTech Connect

    Frese, Michael H.; Frese, Sherry D.

    2013-11-01

    The purpose of this research has been to study the physics of macroscopic magnetized high-energy-density laboratory plasmas (HEDLPs) created through the compression of a high-beta compact toroid (CT) plasma having closed magnetic field lines. The high-beta CT chosen for this work is a field-reversed configuration (FRC). The basic approach is to investigate CT plasmas as they are compressed to a HED state by the electromagnetic implosion of a surrounding metallic shell or solid liner (Figure 1). The shell provides an axisymmetric, electrically-conducting boundary around the plasma and its supporting magnetic field and is imploded by means of the magnetic pressure force arising from axial current flow in the liner interacting with its associated azimuthal magnetic field. Compression of the CT will bring the plasma to fusion temperatures at higher densities and magnetic fields (multi-MegaGauss [MG]) than have previously been present in conventional magnetic fusion approaches. The resulting energy densities will be ~1 Mbar or greater and thus will place the plasma in a parameter space intermediate to MFE and IFE. This work has been a collaboration between the Air Force Research Laboratory, Los Alamos National Laboratory, and NumerEx, LLC.

  7. Developments in digital in-line holography enable validated measurement of 3D particle field dynamics.

    SciTech Connect

    Guildenbecher, Daniel Robert

    2013-12-01

    Digital in-line holography is an optical technique which can be applied to measure the size, three-dimensional position, and three-component velocity of disperse particle fields. This work summarizes recent developments at Sandia National Laboratories focused on improvement in measurement accuracy, experimental validation, and applications to multiphase flows. New routines are presented which reduce the uncertainty in measured position along the optical axis to a fraction of the particle diameter. Furthermore, application to liquid atomization highlights the ability to measure complex, three-dimensional structures. Finally, investigation of particles traveling at near sonic conditions prove accuracy despite significant experimental noise due to shock-waves.

  8. HHFW Power Flow Along Magnetic Field Lines In The Scrape-off Layer of NSTX

    SciTech Connect

    Rory Perkins, et. al.

    2012-02-27

    A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast wave heating and current drive.

  9. Kilometric radio waves generated along auroral field lines observed by ground facilities - A theoretical model

    NASA Technical Reports Server (NTRS)

    Ziebell, L. F.; Wu, C. S.; Yoon, Peter H.

    1991-01-01

    A theory of generation of radio waves observed by ground-based facilities in the frequency range 150-700 kHz is discussed. This work is a continuation of an earlier discussion (Wu et al., 1989) in which it was proposed that the trapped electrons along the auroral field lines can lead to a cyclotron instability which amplifies the whistler waves observed at ground level. The objective of the present study is to investigate the propagation effect on the wave amplification and to examine whether the proposed mechanism is indeed viable.

  10. Magnetic field connected fast line profile variability in spectra of bright O supergiants

    NASA Astrophysics Data System (ADS)

    Kholtygin, A.; Brown, J.; Fabrika, S.; Surkov, A.

    2004-10-01

    Results of study of fast line profile variability (lpv) in the spectra of selected bright O-stars are reported. A regular component of lpv in the spectra of the star λ Ori A with estimated period P≈ 3 d have been detected. We suppose that the formation of long time-scale regular components of lpv can be explained in the framework of the magnetically confined wind-shock (MCWS) model of Babel & Montmerle (1997a). In the context of testing the MCWS model the program of searching for weak magnetic fields in bright O and early B stars is outlined. The possibility of measuring weak longitudinal magnetic fields (Bl ≈ 100 G) is demonstrated.

  11. A novel lateral diffused metal oxide semiconductor (LDMOS) by attracting the electric field Lines

    NASA Astrophysics Data System (ADS)

    Orouji, Ali A.; Hanaei, Mahsa

    2015-11-01

    In this paper, a novel silicon on insulator (SOI) lateral diffused metal oxide semiconductor (LDMOS) transistor with high voltage and high frequency performance is presented. In this work we try to reduce the electric field crowding in the drift region. The proposed structure consists of a metal in the buried oxide and also connected to the source. The inserted metal attracts the electric field lines in the buried oxide. It causes 67% improvement in the breakdown voltage in comparison with a conventional SOI-LDMOS (C-LDMOS). Our simulations with two dimensional ATLAS simulator show that the gate-drain capacitance improves in the proposed structure. The unilateral power gain also enhances. So, the proposed structure is suitable for high voltage and high frequency applications.

  12. Time-reversed particle dynamics calculation with field line tracing at Titan - an update

    NASA Astrophysics Data System (ADS)

    Bebesi, Zsofia; Erdos, Geza; Szego, Karoly; Juhasz, Antal; Lukacs, Katalin

    2014-05-01

    We use CAPS-IMS Singles data of Cassini measured between 2004 and 2010 to investigate the pickup process and dynamics of ions originating from Titan's atmosphere. A 4th order Runge-Kutta method was applied to calculate the test particle trajectories in a time reversed scenario, in the curved magnetic environment. We evaluated the minimum variance directions along the S/C trajectory for all Cassini flybys during which the CAPS instrument was in operation, and assumed that the field was homogeneous perpendicular to the minimum variance direction. We calculated the magnetic field lines with this method along the flyby orbits and we could determine those observational intervals when Cassini and the upper atmosphere of Titan could be magnetically connected. We used three ion species (1, 2 and 16 amu ions) for time reversed tracking, and also considered the categorization of Rymer et al. (2009) and Nemeth et al. (2011) for further features studies.

  13. A Morphological Study of Compact Narrow Emission Line Galaxies In The COSMOS Field

    NASA Astrophysics Data System (ADS)

    Baldassare, Vivienne; Feldman, D.; Greenbaum, A.; Hasan, I.; Mahalchick, S.; Liu, C.; COSMOS Team

    2010-01-01

    We present a morphological study of 139 spectroscopically selected compact narrow emission line galaxies (CNELGs) from the COSMOS HST Treasury Survey, using a comparison sample of field galaxies of similar magnitude obtained from the COSMOS field. The CNELGs range in magnitude from 18.13 < V < 21.95 and in redshift from 0 < z < 0.9. Preliminary results indicate that, whereas statistically the CNELGs are clearly morphologically distinct from our comparison sample, at HST resolution they are also clearly not all - or even predominantly - "compact." This work was supported by an NSF REU Site grant to The City University of New York and American Museum of Natural History; an NSF STEAM grant to the College of Staten Island; the NASA New York Space Grant program; Barnard College; and the CUNY Macaulay Honors College.

  14. Auroral displays near the 'foot' of the field line of the ATS-5 satellite

    NASA Technical Reports Server (NTRS)

    Akasofu, S.-I.; Deforest, S.; Mcilwain, C.

    1974-01-01

    Summary of an extensive correlative study of ATS-5 particle and magnetic field data with all-sky photographs from Great Whale River which is near the 'foot' of the field lines passing through the ATS-5 satellite. In particular, an effort is made to identify specific particle features with specific auroral displays during substorms, such as a westward traveling surge, poleward expansive motion, and drifting patches. It is found that, in early evening hours, the first encounter of ATS-5 with hot plasma is associated with the equatorward shift of the diffuse aurora, but not necessarily with westward traveling surges (even when the satellite is embedded in the plasma sheet). In the midnight sector, an injection corresponds very well to the initial brightening of an auroral arc. Specific features of morning sector auroras are difficult to correlate with specific particle features.

  15. Field fabrication and installation of flangeless connections for plastic-lined piping

    SciTech Connect

    Kalnins, J.M.

    1996-07-01

    The chemical process industries have relied on Plastic-Lined Piping (PLP) to solve complex corrosion problems for over forty years. The Fugitive Emissions Regulations of the 1990 Clean Air Act Amendments have created concerns about the large number of flanged connections traditionally associated with PLP. In the past several years, new joint reduction technologies have been introduced to minimize the number of flanged connections in a PLP system. These technologies incorporate new piping and bending technology and flangeless joints to create fabricated PLP assemblies. Until recently, the flangeless joints were limited to factory-fabricated assemblies. New technology permits the flangeless joints to be created in the field using a novel mechanical connection. This novel mechanical connection, field-fabrication and installation aspects of the flangeless connection are discussed.

  16. Ion gyroradius effects on particle trapping in kinetic Alfven waves along auroral field lines

    DOE PAGES

    Damiano, P. A.; Johnson, J. R.; Chaston, C. C.

    2016-11-10

    In this study, a 2-D self-consistent hybrid gyrofluid-kinetic electron model is used to investigate Alfven wave propagation along dipolar magnetic field lines for a range of ion to electron temperature ratios. The focus of the investigation is on understanding the role of these effects on electron trapping in kinetic Alfven waves sourced in the plasma sheet and the role of this trapping in contributing to the overall electron energization at the ionosphere. This work also builds on our previous effort by considering a similar system in the limit of fixed initial parallel current, rather than fixed initial perpendicular electric field.more » It is found that the effects of particle trapping are strongest in the cold ion limit and the kinetic Alfven wave is able to carry trapped electrons a large distance along the field line yielding a relatively large net energization of the trapped electron population as the phase speed of the wave is increased. However, as the ion temperature is increased, the ability of the kinetic Alfven wave to carry and energize trapped electrons is reduced by more significant wave energy dispersion perpendicular to the ambient magnetic field which reduces the amplitude of the wave. This reduction of wave amplitude in turn reduces both the parallel current and the extent of the high-energy tails evident in the energized electron populations at the ionospheric boundary (which may serve to explain the limited extent of the broadband electron energization seen in observations). Here, even in the cold ion limit, trapping effects in kinetic Alfven waves lead to only modest electron energization for the parameters considered (on the order of tens of eV) and the primary energization of electrons to keV levels coincides with the arrival of the wave at the ionospheric boundary.« less

  17. Ion gyroradius effects on particle trapping in kinetic Alfven waves along auroral field lines

    SciTech Connect

    Damiano, P. A.; Johnson, J. R.; Chaston, C. C.

    2016-11-10

    In this study, a 2-D self-consistent hybrid gyrofluid-kinetic electron model is used to investigate Alfven wave propagation along dipolar magnetic field lines for a range of ion to electron temperature ratios. The focus of the investigation is on understanding the role of these effects on electron trapping in kinetic Alfven waves sourced in the plasma sheet and the role of this trapping in contributing to the overall electron energization at the ionosphere. This work also builds on our previous effort by considering a similar system in the limit of fixed initial parallel current, rather than fixed initial perpendicular electric field. It is found that the effects of particle trapping are strongest in the cold ion limit and the kinetic Alfven wave is able to carry trapped electrons a large distance along the field line yielding a relatively large net energization of the trapped electron population as the phase speed of the wave is increased. However, as the ion temperature is increased, the ability of the kinetic Alfven wave to carry and energize trapped electrons is reduced by more significant wave energy dispersion perpendicular to the ambient magnetic field which reduces the amplitude of the wave. This reduction of wave amplitude in turn reduces both the parallel current and the extent of the high-energy tails evident in the energized electron populations at the ionospheric boundary (which may serve to explain the limited extent of the broadband electron energization seen in observations). Here, even in the cold ion limit, trapping effects in kinetic Alfven waves lead to only modest electron energization for the parameters considered (on the order of tens of eV) and the primary energization of electrons to keV levels coincides with the arrival of the wave at the ionospheric boundary.

  18. On the Sources Above the Neutral Line of Radial Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Stupishin, A. G.; Bogod, V. M.; Yasnov, L. V.

    2012-04-01

    In this work we continue the investigation of the radio sources above the neutral line of radial magnetic field (NLS), since their nature remains still unclear. So, for example, the problem of non-thermal nature of "halo" sources (NLSs with relatively big angular size) requires additional discussion. We investigated NLSs with wide range of their sizes and with quite different spectral characteristic of emission. It was noted that the flux of NLS increases with the increasing of quasi-longitudinal magnetic field gradient on the photosphere. NLS in AR NOAA 10486 lies in the base of the current sheet. It is quite possible that this fact is the reason of the narrow-band spectral peculiarity: the antenna temperature (in polarization) is positive at the wavelength 5.26 cm, while it is negative on the neighbor wavelengths. The sharp temperature change from positive to negative values (temperature inversion) occurs while the wavelength changes from 5.26 cm to 6.52 cm. Such spectral behavior causes by relative decreasing of the extraordinary emission, and can be observed when hot areas (with a characteristic size about 1 Mm) occurs on the line-of-sight. Such spectral detail can be related to the "bridge" between two regions of photosphere magnetic fields through the region of the field with opposite polarity. It is most probably that NLSs are placed in the top of the coronal loop. Observed weak polarization of NLSs (including halo-NLS) describes well in the terms of cyclotron emission mechanism. Theoretical analysis of the sources spectra in the top of the coronal loop (i.e. in the quasi-transversal propagation conditions) shows that the modeled emission angle distribution is like the halo-NLS one (e.g. the polarization degree decreases in the range of 60 to 85 degrees).

  19. Detecting planets around active stars: impact of magnetic fields on radial velocities and line bisectors

    NASA Astrophysics Data System (ADS)

    Hébrard, É. M.; Donati, J.-F.; Delfosse, X.; Morin, J.; Boisse, I.; Moutou, C.; Hébrard, G.

    2014-09-01

    Although technically challenging, detecting Earth-like planets around very low mass stars is in principle accessible to the existing velocimeters of highest radial-velocity (RV) precision. However, low-mass stars being active, they often feature dark spots and magnetic regions at their surfaces generating a noise level in RV curves (called activity jitter) that can severely limit our practical ability at detecting Earth-like planets. Whereas the impact of dark spots on RV data has been extensively studied in the literature, that of magnetic features only received little attention up to now. In this paper, we aim at quantifying the impact of magnetic fields (and the Zeeman broadening they induce) on line profiles, line bisectors and RV data. With a simple model, we quantitatively study the RV signals and bisector distortions that small magnetic regions or global magnetic dipoles can generate, especially at infrared wavelengths where the Zeeman broadening is much larger than that in the visible. We report in particular that the impact of magnetic features on line bisectors can be different from that of cool spots when the rotational broadening is comparable to or larger than the Zeeman broadening; more specifically, we find in this case that the top and bottom sections of the bisectors are anticorrelated, i.e. the opposite behaviour of what is observed for cool spots. We finally suggest new options to show and ultimately filter the impact of the magnetic activity on RV curves.

  20. High-magnetic-field transport properties and irreversibility line of single crystals (2212) and ceramics of BPSCCO (2223)

    NASA Astrophysics Data System (ADS)

    Pradhan, A. K.; Chen, C.; Wanklyn, B. M.

    1995-02-01

    We have measured the high-magnetic-field (up to 15 T) transport properties of (BiPb) 2Sr 2Ca 1Cu 2O y (BPSCCO) single crystals and (2223) ceramics. We have extracted the melting line of BPSCCO crystals from the measurements of precise I- V curves when the field is applied parallel to the c-axis and shown that the melting line coincides with the irreversibility line measured by the magnetisation technique. This is explained for the case of weak pinning. The depinning line was found to be 10 to 12 K above the melting line. The observed hump in the magnetoresistance curve above 2 T predicts the depinning of flux from the weak pinning centres when the temperature approaches the depinning temperature. The basic behavior of ceramic BPSCCO, although having a higher Tc, is similar to its single crystal analogue with (2212) phase except for the enhanced depinning line.

  1. 3-D Modelling of Stretched Solitary Waves along Magnetic Field Lines

    NASA Astrophysics Data System (ADS)

    Muschietti, L.; Roth, I.; Carlson, C. W.; Berthomier, M.

    2001-12-01

    A model is presented for a new type of fast solitary waves which is observed by FAST in downward current regions of the auroral zone. The three-dimensional, coherent structures are electrostatic, have a positive potential, and move along the ambient magnetic field lines with speeds on the order of the electron drift. Their potential profile in the parallel direction, which can be directly measured, is flat-top whereby it cannot fit to the Gaussian shape used in previous work. Their potential profile in the perpendicular direction can only be inferred from a measured unipolar electric signal. We develop an extended BGK model which includes a flattened potential and an assumed cylindrical symmetry around a centric magnetic field line. The model envisions concentric shells of trapped electrons slowly drifting azimuthally while bouncing back and forth in the parallel direction. The electron dynamics is analysed in terms of three basic motions that occur on different time scales. These are defined by the cyclotron frequency Ω e, the bounce frequency ω b, and the azimuthal drift frequency ω γ , for which explicit analytical expressions are obtained. Subject to the ordering ω γ <<ωb<< Ωe, we calculate self-consistent distribution functions in terms of approximate constants of motion. Constraints on the parameters characterizing the amplitude and shape of the stretched solitary wave are discussed.

  2. Propagation speed of rotation signals for field lines undergoing magnetic reconnection

    SciTech Connect

    Lapenta, Giovanni; Goldman, Martin; Newman, David; Markidis, Stefano

    2013-10-15

    Reconnection is associated with two bending of the magnetic field lines. Considering the usual plane of a 2D reconnection simulation, the first bending is in-plane and produces the needed topological changes by bringing oppositely directed filed lines in proximity. The second is typical of fast reconnection and is out of plane, leading to the formation of the Hall magnetic field. This second rotation has recently been observed to proceed at superAlfvénic speeds and to carry substantial energy fluxes (Shay et al., Phys. Rev. Lett. 107, 065001 (2011)). We revisit these rotations with a new diagnostics based on dispersing a multitude of virtual probes into a kinetic simulation, akin the approach of multi spacecraft missions. The results of the new diagnostics are compared with the theory of characteristics applied to the two fluid model. The comparison of virtual probes and the method of characteristics confirm the findings relative to the out of plane rotation and uncover the existence of two families of characteristics. Both are observed in the simulation. The early stage of reconnection develops on the slower compressional branch and the later faster phase develops on the faster torsional branch. The superAlfvénic signal is only relevant in the second phase.

  3. Global Simulation of Proton Precipitation Due to Field Line Curvature During Substorms

    NASA Technical Reports Server (NTRS)

    Gilson, M. L.; Raeder, J.; Donovan, E.; Ge, Y. S.; Kepko, L.

    2012-01-01

    The low latitude boundary of the proton aurora (known as the Isotropy Boundary or IB) marks an important boundary between empty and full downgoing loss cones. There is significant evidence that the IB maps to a region in the magnetosphere where the ion gyroradius becomes comparable to the local field line curvature. However, the location of the IB in the magnetosphere remains in question. In this paper, we show simulated proton precipitation derived from the Field Line Curvature (FLC) model of proton scattering and a global magnetohydrodynamic simulation during two substorms. The simulated proton precipitation drifts equatorward during the growth phase, intensifies at onset and reproduces the azimuthal splitting published in previous studies. In the simulation, the pre-onset IB maps to 7-8 RE for the substorms presented and the azimuthal splitting is caused by the development of the substorm current wedge. The simulation also demonstrates that the central plasma sheet temperature can significantly influence when and where the azimuthal splitting takes place.

  4. Quasilinear theory of interchange modes in a closed field line configuration

    SciTech Connect

    Kouznetsov, A.; Freidberg, J. P.; Kesner, J.

    2007-10-15

    Two important issues for any magnetic fusion configuration are the maximum achievable values of {beta} and energy confinement time when ideal magnetohydrodynamic (MHD) modes are excited. It is well known that the excitation of the MHD unstable modes typically can lead to violent restructuring of the plasma profiles. The particle and energy transport associated with these modes normally dominates all other transport mechanisms and can lead to plasma disruptions and a rapid loss of energy. This paper analytically investigates the transport of particle density, energy, and magnetic field due to the ideal MHD interchange mode in a closed-line system using the quasilinear approximation. The transport equations are derived for a static plasma in a hardcore Z-pinch configuration and generalized to an arbitrary axisymmetric toroidal closed poloidal field line configuration. It is shown that violation of the marginal stability criterion leads to rapid quasilinear transport that drives the pressure profile back to its marginal profile and forces the particle density to be inversely proportional to {integral}dl/B. The applicability of the quasilinear approximation is numerically tested for the hardcore Z-pinch magnetic configuration using a full nonlinear code.

  5. Development and field performance of nitrogen use efficient rice lines for Africa.

    PubMed

    Selvaraj, Michael Gomez; Valencia, Milton Orlando; Ogawa, Satoshi; Lu, Yingzhi; Wu, Liying; Downs, Christopher; Skinner, Wayne; Lu, Zhongjin; Kridl, Jean C; Ishitani, Manabu; van Boxtel, Jos

    2016-11-27

    Nitrogen (N) fertilizers are a major input cost in rice production, and its excess application leads to major environmental pollution. Development of rice varieties with improved nitrogen use efficiency (NUE) is essential for sustainable agriculture. Here, we report the results of field evaluations of marker-free transgenic NERICA4 (New Rice for Africa 4) rice lines overexpressing barley alanine amino transferase (HvAlaAT) under the control of a rice stress-inducible promoter (pOsAnt1). Field evaluations over three growing seasons and two rice growing ecologies (lowland and upland) revealed that grain yield of pOsAnt1:HvAlaAT transgenic events was significantly higher than sibling nulls and wild-type controls under different N application rates. Our field results clearly demonstrated that this genetic modification can significantly increase the dry biomass and grain yield compared to controls under limited N supply. Increased yield in transgenic events was correlated with increased tiller and panicle number in the field, and evidence of early establishment of a vigorous root system in hydroponic growth. Our results suggest that expression of the HvAlaAT gene can improve NUE in rice without causing undesirable growth phenotypes. The NUE technology described in this article has the potential to significantly reduce the need for N fertilizer and simultaneously improve food security, augment farm economics and mitigate greenhouse gas emissions from the rice ecosystem.

  6. Remote field trips and on-line exhibitions: public understanding of research projects at the Exploratorium

    NASA Astrophysics Data System (ADS)

    Semper, R.; Hawkins, I.

    2003-04-01

    Science museums and science centers provide an opportunity for students and members of the general public to explore the world of science and technology through exhibits, objects and public programs. But it is often difficult to present the flavor and atmosphere of current scientific exploration in a museum setting. Recent advances in technology have facilitated the development of remote field trips to places of science creation and online exhibitions using the actual data of science research for both an on site and on line audiences. Over the past five years the Exploratorium has explored using its museum design sensibilities in combination with the Internet to present current scientific research to a broad public and school audience. Live @ the Exploratorium combines remote production from interesting scientific locations with a live studio audience on the museum’s exhibit floor to create Webcasts and Websites which provide an on-line audience with a unique fieldtrip experience. This program has visited research laboratories in Antarctica, field sites along the San Andrea Fault in California, and the Space Telescope Science Institute in Baltimore that operates the Hubble Space Telescope. The Research Explorer project uses museum exhibit interpretive skills to create an on-line exhibition on current research data in global climate change or solar activity by providing a window onto the actual dynamic research activity available on the Web. In both of these projects the museum makes use of its content, pedagogy and design capabilities to act as a mediator between the world of science and the world of the public.

  7. Diagnostics of Local Magnetic Fields in Solar Flares Using FeI 5383 and MgI 5528 Lines

    NASA Astrophysics Data System (ADS)

    Lozitsky, V. G.; Lozitsky, O. V.

    Main purpose of the present work is to estimate upper limit of the local magnetic field strength in solar flares using spectral lines FeI 5383 and MgI 5528. These lines like FeI 5233 have low Lande factors (1.12 and 1.00, respectively) and relatively large spectral width (0.2-0.3 Å). On this account, even in a case of very strong fields (3-4 kG) they must show the simple picture of the Zeeman splitting, with parallel to each other the bisectors of profiles I+V and I - V. In actual fact, another picture was found for nine flares: bisectors of these lines have maximums of splitting on certain distances from line center, what must not be in the homogeneous magnetic field. In particular, both lines have peak of bisector splitting on distance 150-170 mÅ from line center. If we assume the Zeeman nature of named peculiarities then necessary fields are 11.2 kG for FeI 5383 and 10.5-11.2 kG for MgI 5528. Likely, this agreement of field values is a new argument to reality of such very strong magnetic fields in flares.

  8. Latitude-independent Pc5 Geomagnetic Pulsations Associated With Field Line Resonance

    NASA Astrophysics Data System (ADS)

    Sung, S.; Kim, K.; Lee, D.; Cattell, C. A.; Andre, M.; Khotyaintsev, Y. V.

    2004-12-01

    The latitude-independent Pc5 pulsations with a spectral peak at ˜2.8 mHz were observed with IMAGE and SAMNET magnetometer array in the morning sector (0700-1000 local time) on April 29 (Day 119), 2001. The spectral amplitude had a local peak at ˜67° geomagnetic latitude, where a sudden phase change of ˜180° appeared. A vortical equivalent ionospheric current structure centered at latitude between 67° and 71° was observed during the Pc5 pulsations and the rotational sense of the current vortex was reversed for one cycle of the pulsation. During the interval of the enhancement of the Pc5 pulsations, the POLAR spacecraft in the morning side crossed near the magnetic shell (L ˜ 8) corresponding to the latitude where the spectral amplitude was maximum, and observed ˜2.8 mHz pulsations in the radial electric field and compressional magnetic field components. Since the toroidal mode Alfvén waves in the magnetosphere are characterized by an electric field perturbation in the radial direction, the simultaneous presence of the pulsations in both components indicates that a field line resonance (FLR) was driven by compressional Pc5 pulsations. Using solar wind data, we conformed that the compressional Pc5 pulsations at POLAR occurred during an interval of enhanced solar wind dynamic pressure. From the analysis of the ground magnetometer data and POLAR data, we suggest that latitude independent ground magnetic perturbations are caused by the vortical equivalent current generated by FLR-associated field-aligned currents.

  9. On the Distribution of Ion Density Depletion Along Magnetic Field Lines as Deduced Using C-NOFS

    NASA Technical Reports Server (NTRS)

    Dao, E.; Kelley, M. C.; Hysell, D. L.; Retterer, J. M.; Su, Y.-J.; Pfaff, Robert F.; Roddy, P. A.; Ballenthin, J. O.

    2012-01-01

    To investigate ion density depletion along magnetic field lines, we compare in situ-measured ion density fluctuations as seen from C/NOFS and compare them to the field-line-integrated depletion of the whole bubble as inferred from electric field measurements. Results show that, within C/NOFS' range, local measurement of the normalized density depletion, (Delta)n/n(sub 0), near the apex may be far less than at other points on the same field line. We argue that the distribution of (Delta)n/n(sub 0) is a weighted distribution concentrated at latitudes of the Appleton anomalies and becomes more heavily weighted the closer the field-aligned bubble rises to the peak of the anomalies. A three-dimensional simulation of an ionospheric bubble verifies our arguments.

  10. Relative localization in wireless sensor networks for measurement of electric fields under HVDC transmission lines.

    PubMed

    Cui, Yong; Wang, Qiusheng; Yuan, Haiwen; Song, Xiao; Hu, Xuemin; Zhao, Luxing

    2015-02-04

    In the wireless sensor networks (WSNs) for electric field measurement system under the High-Voltage Direct Current (HVDC) transmission lines, it is necessary to obtain the electric field distribution with multiple sensors. The location information of each sensor is essential to the correct analysis of measurement results. Compared with the existing approach which gathers the location information by manually labelling sensors during deployment, the automatic localization can reduce the workload and improve the measurement efficiency. A novel and practical range-free localization algorithm for the localization of one-dimensional linear topology wireless networks in the electric field measurement system is presented. The algorithm utilizes unknown nodes' neighbor lists based on the Received Signal Strength Indicator (RSSI) values to determine the relative locations of nodes. The algorithm is able to handle the exceptional situation of the output permutation which can effectively improve the accuracy of localization. The performance of this algorithm under real circumstances has been evaluated through several experiments with different numbers of nodes and different node deployments in the China State Grid HVDC test base. Results show that the proposed algorithm achieves an accuracy of over 96% under different conditions.

  11. A partially mesh-free scheme for representing anisotropic spatial variations along field lines

    NASA Astrophysics Data System (ADS)

    McMillan, Ben F.

    2017-03-01

    A common numerical task is to represent functions which are highly spatially anisotropic, and to solve differential equations related to these functions. One way such anisotropy arises is that information transfer along one spatial direction is much faster than in others. In this situation, the derivative of the function is small in the local direction of a vector field B. In order to define a discrete representation, a set of surfaces Mi indexed by an integer i are chosen such that mapping along the field B induces a one-to-one relation between the points on surface Mi to those on Mi+1. For simple cases Mi may be surfaces of constant coordinate value. On each surface Mi, a function description is constructed using basis functions defined on a regular structured mesh. The definition of each basis function is extended from the surface M along the lines of the field B by multiplying it by a smooth compact support function whose argument increases with distance along B. Function values are evaluated by summing contributions associated with each surface Mi. This does not require any special connectivity of the meshes used in the neighbouring surfaces M, which substantially simplifies the meshing problem compared to attempting to find a space filling anisotropic mesh. We explore the numerical properties of the scheme, and show that it can be used to efficiently solve differential equations for certain anisotropic problems.

  12. Relative Localization in Wireless Sensor Networks for Measurement of Electric Fields under HVDC Transmission Lines

    PubMed Central

    Cui, Yong; Wang, Qiusheng; Yuan, Haiwen; Song, Xiao; Hu, Xuemin; Zhao, Luxing

    2015-01-01

    In the wireless sensor networks (WSNs) for electric field measurement system under the High-Voltage Direct Current (HVDC) transmission lines, it is necessary to obtain the electric field distribution with multiple sensors. The location information of each sensor is essential to the correct analysis of measurement results. Compared with the existing approach which gathers the location information by manually labelling sensors during deployment, the automatic localization can reduce the workload and improve the measurement efficiency. A novel and practical range-free localization algorithm for the localization of one-dimensional linear topology wireless networks in the electric field measurement system is presented. The algorithm utilizes unknown nodes' neighbor lists based on the Received Signal Strength Indicator (RSSI) values to determine the relative locations of nodes. The algorithm is able to handle the exceptional situation of the output permutation which can effectively improve the accuracy of localization. The performance of this algorithm under real circumstances has been evaluated through several experiments with different numbers of nodes and different node deployments in the China State Grid HVDC test base. Results show that the proposed algorithm achieves an accuracy of over 96% under different conditions. PMID:25658390

  13. Jet outflow and open field line measurements on the C-2U advanced beam-driven field-reversed configuration plasma experiment

    NASA Astrophysics Data System (ADS)

    Sheftman, D.; Gupta, D.; Roche, T.; Thompson, M. C.; Giammanco, F.; Conti, F.; Marsili, P.; Moreno, C. D.

    2016-11-01

    Knowledge and control of the axial outflow of plasma particles and energy along open-magnetic-field lines are of crucial importance to the stability and longevity of the advanced beam-driven field-reversed configuration plasma. An overview of the diagnostic methods used to perform measurements on the open field line plasma on C-2U is presented, including passive Doppler impurity spectroscopy, microwave interferometry, and triple Langmuir probe measurements. Results of these measurements provide the jet ion temperature and axial velocity, electron density, and high frequency density fluctuations.

  14. Solar magnetic field studies using the 12 micron emission lines. I - Quiet sun time series and sunspot slices

    NASA Technical Reports Server (NTRS)

    Deming, Drake; Boyle, Robert J.; Jennings, Donald E.; Wiedemann, Gunter

    1988-01-01

    The use of the extremely Zeeman-sensitive IR emission line Mg I, at 12.32 microns, to study solar magnetic fields. Time series observations of the line in the quiet sun were obtained in order to determine the response time of the line to the five-minute oscillations. Based upon the velocity amplitude and average period measured in the line, it is concluded that it is formed in the temperature minimum region. The magnetic structure of sunspots is investigated by stepping a small field of view in linear 'slices' through the spots. The region of penumbral line formation does not show the Evershed outflow common in photospheric lines. The line intensity is a factor of two greater in sunspot penumbrae than in the photosphere, and at the limb the penumbral emission begins to depart from optical thinness, the line source function increasing with height. For a spot near disk center, the radial decrease in absolute magnetic field strength is steeper than the generally accepted dependence.

  15. Relaxation dynamics of vortex lines in disordered type-II superconductors following magnetic field and temperature quenches.

    PubMed

    Assi, Hiba; Chaturvedi, Harshwardhan; Dobramysl, Ulrich; Pleimling, Michel; Täuber, Uwe C

    2015-11-01

    We study the effects of rapid temperature and magnetic field changes on the nonequilibrium relaxation dynamics of magnetic vortex lines in disordered type-II superconductors by employing an elastic line model and performing Langevin molecular dynamics simulations. In a previously equilibrated system, either the temperature is suddenly changed or the magnetic field is instantaneously altered which is reflected in adding or removing flux lines to or from the system. The subsequent aging properties are investigated in samples with either randomly distributed pointlike or extended columnar defects, which allows us to distinguish the complex relaxation features that result from either type of pinning centers. One-time observables such as the radius of gyration and the fraction of pinned line elements are employed to characterize steady-state properties, and two-time correlation functions such as the vortex line height autocorrelations and their mean-square displacement are analyzed to study the nonlinear stochastic relaxation dynamics in the aging regime.

  16. High-speed, digitally refocused retinal imaging with line-field parallel swept source OCT

    NASA Astrophysics Data System (ADS)

    Fechtig, Daniel J.; Kumar, Abhishek; Ginner, Laurin; Drexler, Wolfgang; Leitgeb, Rainer A.

    2015-03-01

    MHz OCT allows mitigating undesired influence of motion artifacts during retinal assessment, but comes in state-of-the-art point scanning OCT at the price of increased system complexity. By changing the paradigm from scanning to parallel OCT for in vivo retinal imaging the three-dimensional (3D) acquisition time is reduced without a trade-off between speed, sensitivity and technological requirements. Furthermore, the intrinsic phase stability allows for applying digital refocusing methods increasing the in-focus imaging depth range. Line field parallel interferometric imaging (LPSI) is utilizing a commercially available swept source, a single-axis galvo-scanner and a line scan camera for recording 3D data with up to 1MHz A-scan rate. Besides line-focus illumination and parallel detection, we mitigate the necessity for high-speed sensor and laser technology by holographic full-range imaging, which allows for increasing the imaging speed by low sampling of the optical spectrum. High B-scan rates up to 1kHz further allow for implementation of lable-free optical angiography in 3D by calculating the inter B-scan speckle variance. We achieve a detection sensitivity of 93.5 (96.5) dB at an equivalent A-scan rate of 1 (0.6) MHz and present 3D in vivo retinal structural and functional imaging utilizing digital refocusing. Our results demonstrate for the first time competitive imaging sensitivity, resolution and speed with a parallel OCT modality. LPSI is in fact currently the fastest OCT device applied to retinal imaging and operating at a central wavelength window around 800 nm with a detection sensitivity of higher than 93.5 dB.

  17. Influence of line-edge roughness on multiple-gate tunnel field-effect transistors

    NASA Astrophysics Data System (ADS)

    Choi, Woo Young

    2017-04-01

    The influence of fin-line-edge roughness (fin-LER) and gate-LER on multiple-gate (MG) tunnel field-effect transistors (TFETs) has been investigated compared with MG MOSFETs by using full three-dimensional technology computer-aided design (TCAD) simulation. From simulation results, two interesting results have been observed. First, MG TFETs show much less severe gate-LER than MG MOSFETs, which means that only fin-LER can be considered when evaluating the total LER of MG TFETs. Second, TFETs show ∼3× more LER improvement than MOSFETs when their structures are changed from double-gate (DG) to triple-gate (TG) ones. Our findings provide the useful design guidelines of variation-tolerant TFETs.

  18. Semi-flexible gas-insulated transmission line using electric field stress shields

    DOEpatents

    Cookson, A.H.; Dale, S.J.; Bolin, P.C.

    1982-12-28

    A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by use of main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. The flexing elements and the stress shields may also be utilized in connection with a plug and socket arrangement for providing electrical connection between main conductor sections. 10 figs.

  19. Semi-flexible gas-insulated transmission line using electric field stress shields

    DOEpatents

    Cookson, Alan H.; Dale, Steinar J.; Bolin, Philip C.

    1982-12-28

    A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by use of main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. The flexing elements and the stress shields may also be utilized in connection with a plug and socket arrangement for providing electrical connection between main conductor sections.

  20. A boron-lined proportional counter (BLPC) used in a mixed field of reactors

    NASA Astrophysics Data System (ADS)

    Chen, Guo-Yun; Wei, Zhi-Yong; Xin, Yong; Lei, Sheng-Jie; Huang, Fu-Cheng; Huang, San-Bo; Zhu, Li; Zhao, Jing-Wu; Ma, Jia-Yi

    2012-05-01

    A boron-lined proportional counter (BLPC) with a count rate limit close to the multi-wire proportional counter was manufactured to measure the mixed field around reactors. After measurement with a standard Am-Be neutron source (activity: 100 mCi), the results show that the operating voltage of the BLPC is 800 V, the plateau length is 100 V and the slope is 13.2%/100 V. The width and rise time of the output pulse of the BLPC are 1.26 μs and 370 ns, respectively. When the BLPC works at a count rate of 1.0×105 count/s, the pulse pile-up probability of the BLPC is 3.6%. A clear peak can be seen in the pulse height spectrum of the BLPC. and the performances illustrate that a BLPC working in pulse mode can serve as a source range detector of reactors.

  1. Kinetic PIC simulations of reconnection signal propagation parallel to magnetic field lines: Implifications for substorms

    NASA Astrophysics Data System (ADS)

    Shay, M. A.; Drake, J. F.

    2009-12-01

    In a recent substorm case study using THEMIS data [1], it was inferred that auroral intensification occurred 96 seconds after reconnection onset initiated a substorm in the magnetotail. These conclusions have been the subject of some controversy [2,3]. The time delay between reconnection and auroral intensification requires a propagation speed significantly faster than can be explained by Alfvén waves. Kinetic Alfvén waves, however, can be much faster and could possibly explain the time lag. To test this possiblity, we simulate large scale reconnection events with the kinetic PIC code P3D and examine the disturbances on a magnetic field line as it propagates through a reconnection region. In the regions near the separatrices but relatively far from the x-line, the propagation physics is expected to be governed by the physics of kinetic Alfvén waves. Indeed, we find that the propagation speed of the magnetic disturbance roughly scales with kinetic Alfvén speeds. We also examine energization of electrons due to this disturbance. Consequences for our understanding of substorms will be discussed. [1] Angelopoulos, V. et al., Science, 321, 931, 2008. [2] Lui, A. T. Y., Science, 324, 1391-b, 2009. [3] Angelopoulos, V. et al., Science, 324, 1391-c, 2009.

  2. Role of finite ionospheric conductivity on toroidal field line oscillations in the Earth's magnetosphere -- Analytic solutions

    NASA Astrophysics Data System (ADS)

    Bulusu, Jayashree; Sinha, A. K.; Vichare, Geeta

    2016-06-01

    An analytic solution has been formulated to study the role of ionospheric conductivity on toroidal field line oscillations in the Earth's magnetosphere. The effect of ionospheric conductivity is addressed in two limits, viz, (a) when conductance of Alfvén wave is much different from ionospheric Pedersen conductance and (b) when conductance of Alfvén wave is close to the ionospheric Pedersen conductance. In the former case, the damping is not significant and standing wave structures are formed. However, in the latter case, the damping is significant leading to mode translation. Conventionally, "rigid-end" and "free-end" cases refer to eigenstructures for infinitely large and vanishingly small limit of ionospheric conductivity, respectively. The present work shows that when the Pedersen conductance overshoots (undershoots) the Alfvén wave conductance, a free-end (rigid-end) mode gets transformed to rigid-end (free-end) mode with an increase (decrease) in harmonic number. This transformation takes place within a small interval of ionospheric Pedersen conductance around Alfvén wave conductance, beyond which the effect of conductivity on eigenstructures of field line oscillations is small. This regime of conductivity limit (the difference between upper and lower limits of the interval) decreases with increase in harmonic number. Present paper evaluates the damping effect for density index other than the standard density index m = 6, using perturbation technique. It is found that for a small departure from m = 6, both mode frequency and damping rate become a function of Pedersen conductivity.

  3. FIELD LINES TWISTING IN A NOISY CORONA: IMPLICATIONS FOR ENERGY STORAGE AND RELEASE, AND INITIATION OF SOLAR ERUPTIONS

    SciTech Connect

    Rappazzo, A. F.; Velli, M.; Einaudi, G.

    2013-07-10

    We present simulations modeling closed regions of the solar corona threaded by a strong magnetic field where localized photospheric vortical motions twist the coronal field lines. The linear and nonlinear dynamics are investigated in the reduced magnetohydrodynamic regime in Cartesian geometry. Initially the magnetic field lines get twisted and the system becomes unstable to the internal kink mode, confirming and extending previous results. As typical in this kind of investigations, where initial conditions implement smooth fields and flux-tubes, we have neglected fluctuations and the fields are laminar until the instability sets in. However, previous investigations indicate that fluctuations, excited by photospheric motions and coronal dynamics, are naturally present at all scales in the coronal fields. Thus, in order to understand the effect of a photospheric vortex on a more realistic corona, we continue the simulations after kink instability sets in, when turbulent fluctuations have already developed in the corona. In the nonlinear stage the system never returns to the simple initial state with ordered twisted field lines, and kink instability does not occur again. Nevertheless, field lines get twisted, although in a disordered way, and energy accumulates at large scales through an inverse cascade. This energy can subsequently be released in micro-flares or larger flares, when interaction with neighboring structures occurs or via other mechanisms. The impact on coronal dynamics and coronal mass ejections initiation is discussed.

  4. [Evaluation of reports on environmental measurements of electromagnetic fields generated by high voltage transmission lines and substations].

    PubMed

    Szuba, Marek

    2007-01-01

    This paper presents some situations, in which measurements of electromagnetic fields generated by transmission lines and substations should be performed. The range of measurements may differ, but maximum values of electric and magnetic fields and flux density must be identified in all situations. The area with electric field exceeding 1 kV/m should be identified as well. The author also presents basic requirements to be met by the measurement technique. These requirements are specified according to the national standard. Special attention should be paid to the identification of the spatial distribution of electric field and flux density generated in the vicinity of high voltage transmission lines. To verify the measurement results, it is necessary to calculate the distribution of both aforesaid field components. For environmental protection purposes, it is also proposed that the report should include measurements of electromagnetic fields of 50 Hz along with calculated results presented in tables and diagrams.

  5. Excitation of dayside chorus waves due to magnetic field line compression in response to interplanetary shocks

    NASA Astrophysics Data System (ADS)

    Zhou, Chen; Li, Wen; Thorne, Richard M.; Bortnik, Jacob; Ma, Qianli; An, Xin; Zhang, Xiao-jia; Angelopoulos, Vassilis; Ni, Binbin; Gu, Xudong; Fu, Song; Zhao, Zhengyu

    2015-10-01

    The excitation of magnetospheric whistler-mode chorus in response to interplanetary (IP) shocks is investigated using wave data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft. As an example, we show a typical chorus wave excitation following an IP shock event that was observed by THEMIS in the postnoon sector near the magnetopause on 3 August 2010. We then analyze characteristic changes during this event and perform a survey of similar events during the period 2008-2014 using the THEMIS and OMNI data set. Our statistical analysis demonstrates that the chorus wave excitation/intensification in response to IP shocks occurs only at high L shells (L > 8) on the dayside. We analyzed the variations of magnetic curvature following the arrival of the IP shock and found that IP shocks lead to more homogeneous background magnetic field configurations in the near-equatorial dayside magnetosphere; and therefore, the threshold of nonlinear chorus wave growth is likely to be reduced, favoring chorus wave generation. Our results provide the observational evidence to support the concept that the geomagnetic field line configuration plays a key role in the excitation of dayside chorus.

  6. Field test of spectral line intensity parameters for tropospheric water vapor

    NASA Astrophysics Data System (ADS)

    Sierk, B.; Solomon, S.; Daniel, J. S.; Portmann, R. W.; Gutman, S. I.; Langford, A. O.; Eubank, C. S.; Holub, K. H.; Florek, S. V.

    2003-06-01

    We report the results of a field experiment designed to study atmospheric water vapor absorption in the visible and near-infrared spectral regions between 550 and 1000 nm. We carried out spectroscopic ground measurements of direct solar radiation under clear-sky conditions in Boulder, Colorado. The data with a spectral resolution of approximately 1 nm were analyzed using the differential optical absorption spectroscopy (DOAS) technique in five different absorption bands of water vapor. We show that this technique can reveal the broadband effects of errors and inconsistencies in absorption spectra information for the water molecule. Retrievals of column tropospheric water vapor from the field spectra were compared to simultaneous independent estimates from Global Positioning System (GPS) data and radiosonde soundings. The data set is used to critically assess the widely used High-Resolution Transmission Molecular Absorption Database (HITRAN) [, 1998]. The results indicate that line intensities in the 3ν + δ polyad centered at 820 nm are underestimated by 21% with respect to the strong 3ν polyad centered at 940 nm, while the 4ν polyad at 720 nm shows agreement within the measurement accuracy of 3%. Two weaker bands centered at 650 and 590 nm were found to be overestimated by about 8-10%. The effect of the proposed corrections on the absorption of incoming solar flux for a clear-sky atmosphere is estimated to be 0.6 W/m2 for an overhead Sun.

  7. Tomographic imaging system for measuring impurity line emission in a field-reversed configuration

    SciTech Connect

    Roche, T.; Heidbrink, W. W.; McWilliams, R.; Bolte, N.; Garate, E.; Wessel, F.

    2012-10-15

    A 16 chord optical tomography system has been developed and implemented in the flux coil generated-field reversed configuration (FRC). The chords are arranged in two fans of eight, which cover {approx}35% of the vessel area at the midplane. Each illuminate separate photomultiplier tubes (PMTs) which are fitted with narrow band-pass filters. In this case, filters are centered at 434.8 nm to measure emission from singly ionized argon. PMT crosstalk is negligible. Background noise due to electron radiation and H{sub {gamma}} line radiation is <10% of argon emission. The spatial resolution of the reconstruction is 1.5 cm. Argon is introduced using a puff valve and tube designed to impart the gas into the system as the FRC is forming. Reconstruction of experimental data results in time-dependent, 2D emissivity profiles of the impurity ions. Analysis of these data show radial, cross-field diffusion to be in the range of 10-10{sup 3} m{sup 2}/s during FRC equilibrium.

  8. Kubo number and magnetic field line diffusion coefficient for anisotropic magnetic turbulence.

    PubMed

    Pommois, P; Veltri, P; Zimbardo, G

    2001-06-01

    The magnetic field line diffusion coefficients Dx and D(y) are obtained by numerical simulations in the case that all the magnetic turbulence correlation lengths l(x), l(y), and l(z) are different. We find that the variety of numerical results can be organized in terms of the Kubo number, the definition of which is extended from R=(deltaB/B(0))(l(parallel)/l(perpendicular)) to R=(deltaB/B(0))(l(z)/l(x)), for l(x) > or = l(y). Here, l(parallel) (l(perpendicular)) is the correlation length along (perpendicular to) the average field B(0)=B(0)ê(z). We have anomalous, non-Gaussian transport for R less, similar 0.1, in which case the mean square deviation scales nonlinearly with time. For R greater, similar 1 we have several Gaussian regimes: an almost quasilinear regime for 0.1 less, similar R less, similar 1, an intermediate, transition regime for 1 less, similar R less, similar 10, and a percolative regime for R greater, similar 10. An analytical form of the diffusion coefficient is proposed, D(i)=D(deltaBl(z)/B(0)l(x))(mu)(l(i)/l(x))(nu)l(2)(x)/l(z), which well describes the numerical simulation results in the quasilinear, intermediate, and percolative regimes.

  9. Residential magnetic fields, contact voltage and their relationship: the effects of distribution unbalance and residential proximity to a transmission line.

    PubMed

    Kavet, Robert; Daigle, Jeff P; Zaffanella, Luciano E

    2006-12-01

    In previous studies, modeling and measurements have suggested a positive relationship between the average residential magnetic field (B(avg)) and the voltage from the residential water line to earth (V(W-E)). This voltage is the source of exposure to contact current that has been hypothesized to behave as a confounder with respect to the association between residential magnetic fields and childhood leukemia. The previous modeling effort has only considered the influence of distribution lines on the B(avg):V(W-E) relationship. This study extends that analysis to include the effect of distribution line unbalance and the presence of nearby transmission lines. The results show that, compared to balanced systems, unbalanced distribution systems had increased B(avg) and V(W-E), with a relatively greater effect on (VW-E). The presence of a transmission line proportionally increased B(avg) and V(W-E) more on balanced systems than unbalanced systems and attenuated the relationship of B(avg) with V(W-E) on systems with 25% unbalance. Increases in B(avg) due to the transmission line were confined to distances within 100-200 m of the line, but increases in V(W-E) extended to the furthest distance included in the model (365 m). The observations reported may be relevant to prior epidemiological studies of magnetic fields and childhood leukemia, and suggest that research efforts continue to explore the role of contact current in potentially explaining those studies.

  10. Gamma-Gamma Absorption in the Broad Line Region Radiation Fields of Gamma-Ray Blazars

    NASA Astrophysics Data System (ADS)

    Böttcher, Markus; Els, Paul

    2016-04-01

    The expected level of γγ absorption in the Broad Line Region (BLR) radiation field of γ-ray loud Flat Spectrum Radio Quasars (FSRQs) is evaluated as a function of the location of the γ-ray emission region. This is done self-consistently with parameters inferred from the shape of the spectral energy distribution (SED) in a single-zone leptonic EC-BLR model scenario. We take into account all geometrical effects both in the calculation of the γγ opacity and the normalization of the BLR radiation energy density. As specific examples, we study the FSRQs 3C279 and PKS 1510-089, keeping the BLR radiation energy density at the location of the emission region fixed at the values inferred from the SED. We confirm previous findings that the optical depth due to γγ absorption in the BLR radiation field exceeds unity for both 3C279 and PKS 1510-089 for locations of the γ-ray emission region inside the inner boundary of the BLR. It decreases monotonically, with distance from the central engine and drops below unity for locations within the BLR. For locations outside the BLR, the BLR radiation energy density required for the production of GeV γ-rays rapidly increases beyond observational constraints, thus making the EC-BLR mechanism implausible. Therefore, in order to avoid significant γγ absorption by the BLR radiation field, the γ-ray emission region must therefore be located near the outer boundary of the BLR.

  11. Astronomy behind Enemy Lines: Colonial American Field Expeditions, 1761--1780

    NASA Astrophysics Data System (ADS)

    Schechner, Sara J.

    2012-09-01

    In May 1761, John Winthrop packed up two students, two telescopes, a clock, and an octant, and embarked for Newfoundland, to observe the Transit of Venus. Winthrop's departure was hasty. Only days before had the President and Fellows of Harvard College approve Professor Winthrop's request to take the college apparatus behind enemy lines during the French and Indian War, to serve the cause of science. Winthrop knew he had no time to waste if he were to reach St. Johns and properly calibrate his equipment before the Transit. In 1761 Winthrop was the sole North American astronomer in a global network helping to determine the distance from the Earth to the Sun. The expedition was a major achievement for colonial astronomy, especially in time of war. Winthrop, however, looked forward to a second chance to observe a transit in 1769. Benjamin Franklin urged him to go to Lake Superior, but preparations for the transit were thwarted by two events: the loss of Harvard's apparatus in a 1764 fire; and pre-Revolutionary War politics in the American colonies. In the end, Winthrop was forced to content himself with observations in Cambridge. In 1780 Winthrop's successor at Harvard, Samuel Williams, risked the college apparatus once again. During the American War of Independence, he received permission to go behind British enemy lines in order to observe a total solar eclipse in Penobscot Bay, Maine. Limitations placed on his encampment led him to be slightly outside totality, but able to observe what would later be known as Baily's beads. This paper will examine the challenges of observational science in provincial America, especially when one had to negotiate with enemies to have access to the best apparatus and field sites.

  12. In-line application of electric field in capillary separation systems: Joule heating, pH and conductivity.

    PubMed

    Eriksson, Björn O; Skuland, Inger Lill; Marlin, Nicola D; Andersson, Magnus B O; Blomberg, Lars G

    2008-03-15

    This study concerns the technique electric field-assisted capillary liquid chromatography. In this technique, an electric field is applied over the separation capillary in order to provide an additional selectivity. In this technique, the electric field is applied in-line in the separation capillary and here the electric current is the factor limiting the magnitude of applied electric field. The influence of Joule heating and other factors on the current in such systems has been investigated. The temperature in the capillary was first measured within a standard CE set-up, as function of effect per unit of length. Then the same cooling system was applied to an in-line set-up, to replicate the conditions between the two systems, and thus the temperature. Thus Joule heating effects could then be calculated within the in-line system. It was found that for systems applying an electric field in line, the direct influence from Joule heating was only relatively small. The pH in the capillary was measured in the in-line set-up using cresol red/TRIS solutions as pH probe. Significant changes in pH were observed and the results suggested that electrolysis of water is the dominant electrode reaction in the in-line system. In summary, the observed conductivity change in in-line systems was found to be mainly due to the pH change by hydrolysis of water, but primarily not due the temperature change in the capillary column.

  13. Linear polarization of resonance lines in the absence of magnetic fields. I - Slabs of finite optical thickness

    NASA Astrophysics Data System (ADS)

    Faurobert, M.

    1987-05-01

    Effects of partial frequency redistribution on resonance polarization of spectral lines in the absence of magnetic fields are studied for resonance lines formed in finite slabs. The emphasis is on testing the validity (for polarization calculations) of various approximate forms of the so-called RII frequency redistribution function which describes the formation of resonance lines formed in dilute media. Polarization profiles obtained with the angle-dependent RII are compared to profiles calculated with the angle-averaged form of RII and its approximate versions proposed by Kneer and Ayres. A comparison with complete frequency redistribution polarization profiles is also presented.

  14. Characterization of vertical electric fields and associated voltages induced on a overhead power line from close artificially initiated lightning

    NASA Astrophysics Data System (ADS)

    Rubinstein, Marcos; Uman, Martin A.; Thomson, Ewen M.; Medelius, Pedro J.

    1991-08-01

    Measurements were characterized of simultaneous vertical electric fields and voltages induced at both ends of a 448 m overhead power line by artificially initiated lightning return strokes. The lightning discharges struck ground about 20 m from one end of the line. The measured line voltages could be grouped into two categories: those in which multiple, similarly shaped, evenly spaced pulses were observed, which are called oscillatory; and those dominated by a principal pulse with subsidiary oscillations of much smaller amplitude, which are called impulsive. Voltage amplitudes range from tens of kilovolts for oscillatory voltages to hundreds of kilovolts for impulsive voltages.

  15. Laboratory Performance Predicts the Success of Field Releases in Inbred Lines of the Egg Parasitoid Trichogramma pretiosum (Hymenoptera: Trichogrammatidae).

    PubMed

    Coelho, Aloisio; Rugman-Jones, Paul F; Reigada, Carolina; Stouthamer, Richard; Parra, José R P

    2016-01-01

    In this study we assessed the relationship between the laboratory and field performance of different isofemale lines of Trichogramma pretiosum Riley. In comparative assays, we used three rare mitochondrial haplotypes as genetic markers of the isofemale lines, and by introgressing these mitochondrial haplotypes into each of 15 genetically different nuclear lines, also tested the assumption that mitochondria are neutral markers. In a laboratory trial, 45 isofemale lines (15 nuclear genotypes x three mitochondrial haplotypes) were ranked in three categories (best, intermediate and worst) according to the mean offspring production and the proportion of female offspring. Subsequently, lines from each of the three categories were selected for field releases to quantify field parasitism on Ephestia kuehniella. Temporally separate releases were done in a transgenic Bt cornfield, with four plots, each with 50 points of recapture. The points of recapture consisted of trap cards with eggs of E. kuehniella collected daily. The trap cards were maintained in the laboratory at 25°C until the adult wasps emerged, and the maternal identity of the wasps was determined using qPCR and high-resolution melt curve analysis to determine the mitochondrial haplotype. The results showed that these measures of laboratory performance (fecundity and offspring sex ratio) were good predictors of field success in T. pretiosum. We also report strong evidence discrediting the assumption that mitochondria are neutral, in view of the correlation between performance and mitochondrial haplotype.

  16. Laboratory Performance Predicts the Success of Field Releases in Inbred Lines of the Egg Parasitoid Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)

    PubMed Central

    Coelho, Aloisio; Rugman-Jones, Paul F.; Reigada, Carolina; Stouthamer, Richard; Parra, José R. P.

    2016-01-01

    In this study we assessed the relationship between the laboratory and field performance of different isofemale lines of Trichogramma pretiosum Riley. In comparative assays, we used three rare mitochondrial haplotypes as genetic markers of the isofemale lines, and by introgressing these mitochondrial haplotypes into each of 15 genetically different nuclear lines, also tested the assumption that mitochondria are neutral markers. In a laboratory trial, 45 isofemale lines (15 nuclear genotypes x three mitochondrial haplotypes) were ranked in three categories (best, intermediate and worst) according to the mean offspring production and the proportion of female offspring. Subsequently, lines from each of the three categories were selected for field releases to quantify field parasitism on Ephestia kuehniella. Temporally separate releases were done in a transgenic Bt cornfield, with four plots, each with 50 points of recapture. The points of recapture consisted of trap cards with eggs of E. kuehniella collected daily. The trap cards were maintained in the laboratory at 25°C until the adult wasps emerged, and the maternal identity of the wasps was determined using qPCR and high-resolution melt curve analysis to determine the mitochondrial haplotype. The results showed that these measures of laboratory performance (fecundity and offspring sex ratio) were good predictors of field success in T. pretiosum. We also report strong evidence discrediting the assumption that mitochondria are neutral, in view of the correlation between performance and mitochondrial haplotype. PMID:26730735

  17. Bird Radar Validation in the Field by Time-Referencing Line-Transect Surveys

    PubMed Central

    Dokter, Adriaan M.; Baptist, Martin J.; Ens, Bruno J.; Krijgsveld, Karen L.; van Loon, E. Emiel

    2013-01-01

    Track-while-scan bird radars are widely used in ornithological studies, but often the precise detection capabilities of these systems are unknown. Quantification of radar performance is essential to avoid observational biases, which requires practical methods for validating a radar’s detection capability in specific field settings. In this study a method to quantify the detection capability of a bird radar is presented, as well a demonstration of this method in a case study. By time-referencing line-transect surveys, visually identified birds were automatically linked to individual tracks using their transect crossing time. Detection probabilities were determined as the fraction of the total set of visual observations that could be linked to radar tracks. To avoid ambiguities in assigning radar tracks to visual observations, the observer’s accuracy in determining a bird’s transect crossing time was taken into account. The accuracy was determined by examining the effect of a time lag applied to the visual observations on the number of matches found with radar tracks. Effects of flight altitude, distance, surface substrate and species size on the detection probability by the radar were quantified in a marine intertidal study area. Detection probability varied strongly with all these factors, as well as species-specific flight behaviour. The effective detection range for single birds flying at low altitude for an X-band marine radar based system was estimated at ∼1.5 km. Within this range the fraction of individual flying birds that were detected by the radar was 0.50±0.06 with a detection bias towards higher flight altitudes, larger birds and high tide situations. Besides radar validation, which we consider essential when quantification of bird numbers is important, our method of linking radar tracks to ground-truthed field observations can facilitate species-specific studies using surveillance radars. The methodology may prove equally useful for optimising

  18. Bird radar validation in the field by time-referencing line-transect surveys.

    PubMed

    Dokter, Adriaan M; Baptist, Martin J; Ens, Bruno J; Krijgsveld, Karen L; van Loon, E Emiel

    2013-01-01

    Track-while-scan bird radars are widely used in ornithological studies, but often the precise detection capabilities of these systems are unknown. Quantification of radar performance is essential to avoid observational biases, which requires practical methods for validating a radar's detection capability in specific field settings. In this study a method to quantify the detection capability of a bird radar is presented, as well a demonstration of this method in a case study. By time-referencing line-transect surveys, visually identified birds were automatically linked to individual tracks using their transect crossing time. Detection probabilities were determined as the fraction of the total set of visual observations that could be linked to radar tracks. To avoid ambiguities in assigning radar tracks to visual observations, the observer's accuracy in determining a bird's transect crossing time was taken into account. The accuracy was determined by examining the effect of a time lag applied to the visual observations on the number of matches found with radar tracks. Effects of flight altitude, distance, surface substrate and species size on the detection probability by the radar were quantified in a marine intertidal study area. Detection probability varied strongly with all these factors, as well as species-specific flight behaviour. The effective detection range for single birds flying at low altitude for an X-band marine radar based system was estimated at ~1.5 km. Within this range the fraction of individual flying birds that were detected by the radar was 0.50 ± 0.06 with a detection bias towards higher flight altitudes, larger birds and high tide situations. Besides radar validation, which we consider essential when quantification of bird numbers is important, our method of linking radar tracks to ground-truthed field observations can facilitate species-specific studies using surveillance radars. The methodology may prove equally useful for optimising

  19. Evaluating (and Improving) Estimates of the Solar Radial Magnetic Field Component from Line-of-Sight Magnetograms

    NASA Astrophysics Data System (ADS)

    Leka, K. D.; Barnes, G.; Wagner, E. L.

    2017-02-01

    Although for many solar physics problems the desirable or meaningful boundary is the radial component of the magnetic field Br, the most readily available measurement is the component of the magnetic field along the line of sight to the observer, B_{los}. As this component is only equal to the radial component where the viewing angle is exactly zero, some approximation is required to estimate Br at all other observed locations. In this study, a common approximation known as the "μ-correction", which assumes all photospheric field to be radial, is compared to a method that invokes computing a potential field that matches the observed B_{los}, from which the potential field radial component, Br^{pot} is recovered. We demonstrate that in regions that are truly dominated by a radially oriented field at the resolution of the data employed, the μ-correction performs acceptably if not better than the potential-field approach. However, it is also shown that for any solar structure that includes horizontal fields, i.e. active regions, the potential-field method better recovers both the strength of the radial field and the location of magnetic neutral line.

  20. Ion acceleration by Alfvén waves on auroral field lines

    NASA Astrophysics Data System (ADS)

    Bingham, Robert; Eliasson, Bengt; Tito Mendonça, José; Stenflo, Lennart

    2013-05-01

    Observations of ion acceleration along auroral field lines at the boundary of the plasma sheet and tail lobe of the Earth show that the energy of the ions increases with decreasing density. The observations can be explained by ion acceleration through Landau resonance with kinetic Alfvén waves (KAWs) such that kA·vi = ωA, where kA is the wave vector, vi is the ion resonance velocity and ωA is the Alfvén wave frequency. The ion resonance velocities are proportional to the Alfvén velocity which increases with decreasing density. This is in agreement with the data if the process is occurring at the plasma sheet tail lobe boundary. A quasi-linear theory of ion acceleration by KAWs is presented. These ions propagate both down towards and away from the Earth. The paths of the Freja and Polar satellites indicate that the acceleration takes place between the two satellites, between 1Re and 5Re. The downward propagating ions develop a horseshoe-type of distribution which has a positive slope in the perpendicular direction. This type of distribution can produce intense lower hybrid wave activity, which is also observed. Finally, the filamentation of shear Alfvén waves is considered. It may be responsible for large-scale density striations. In memory of Padma Kant Shukla, a great scientist and a good friend.

  1. Identifying Vortex-Core-Line using a tetrahedral satellite configuration: Field Topology Approach

    NASA Astrophysics Data System (ADS)

    Jiang, Yao; Lembege, Bertrand; Nishikawa, Ken-ichi; Cai, DongSheng; Hasegawa, Hiroshi

    2016-04-01

    Identifying vortices are the key to understanding the turbulence in plasma shear layers. Here, the term 'vortex' or 'vortex core' is associated with a region of Galilean invariance [Jeong and Hussain, 1995]. Unfortunately, no single precise definition of a vortex is currently universally accepted, despite the fact that many space plasma authors claim that many observations have detected "vortices" (as Kelvin-Helmholtz vortices at/around the magnetopause). By using the four satellite velocity data, and Taylor series, we expand the velocity data around the satellites, calculate its first order tensor, and linearly approximate the field. We can identify the vortex structures by using various vortex identification criteria as follows: (i) The first criterion is Q-criterion that defines vortices as regions in which the vorticity energy prevails other energies; (ii) the second criterion is the lambda2-criterion that is related to the minus of the Hessian matrix of the pressure related term; and (iii) the third criterion requires the existence of vortex-core-lines that is the Galilean invariance inside the four satellite tetrahedral region. Using these methods, we can identify and analyze more precisely the 3D vortex using tetrahedral satellite configuration.

  2. Multichannel Double-Row Transmission Line Array for Human MR Imaging at Ultrahigh Fields

    PubMed Central

    Yan, Xinqiang; Pedersen, Jan Ole; Wei, Long

    2017-01-01

    Objective In microstrip transmission line (MTL) transmit/receive (transceive) arrays used for ultrahigh field MRI, the array length is often constrained by the required resonant frequency, limiting the image coverage. The purpose of this study is to increase the imaging coverage and also improve its parallel imaging capability by utilizing a double-row design. Methods A 16-channel double-row MTL transceive array was designed, constructed, and tested for human head imaging at 7 T. Array elements between two rows were decoupled by using the induced current elimination or magnetic wall decoupling technique. In vivo human head images were acquired, and g-factor results were calculated to evaluate the performance of this double-row array. Results Testing results showed that all coil elements were well decoupled with a better than −18 dB transmission coefficient between any two elements. The double-row array improves the imaging quality of the lower portion of the human head, and has low g-factors even at high acceleration rates. Conclusion Compared with a regular single-row MTL array, the double-row array demonstrated a larger imaging coverage along the z-direction with improved parallel imaging capability. Significance The proposed technique is particularly suitable for the design of large-sized transceive arrays with large channel counts, which ultimately benefits the imaging performance in human MRI. PMID:25706499

  3. Advanced Discontinuous Galerkin Algorithms and First Open-Field Line Turbulence Simulations

    NASA Astrophysics Data System (ADS)

    Hammett, G. W.; Hakim, A.; Shi, E. L.

    2016-10-01

    New versions of Discontinuous Galerkin (DG) algorithms have interesting features that may help with challenging problems of higher-dimensional kinetic problems. We are developing the gyrokinetic code Gkeyll based on DG. DG also has features that may help with the next generation of Exascale computers. Higher-order methods do more FLOPS to extract more information per byte, thus reducing memory and communications costs (which are a bottleneck at exascale). DG uses efficient Gaussian quadrature like finite elements, but keeps the calculation local for the kinetic solver, also reducing communication. Sparse grid methods might further reduce the cost significantly in higher dimensions. The inner product norm can be chosen to preserve energy conservation with non-polynomial basis functions (such as Maxwellian-weighted bases), which can be viewed as a Petrov-Galerkin method. This allows a full- F code to benefit from similar Gaussian quadrature as used in popular δf gyrokinetic codes. Consistent basis functions avoid high-frequency numerical modes from electromagnetic terms. We will show our first results of 3 x + 2 v simulations of open-field line/SOL turbulence in a simple helical geometry (like Helimak/TORPEX), with parameters from LAPD, TORPEX, and NSTX. Supported by the Max-Planck/Princeton Center for Plasma Physics, the SciDAC Center for the Study of Plasma Microturbulence, and DOE Contract DE-AC02-09CH11466.

  4. Field study of age-differentiated strain for assembly line workers in the automotive industry.

    PubMed

    Börner, Kerstin; Scherf, Christian; Leitner-Mai, Bianca; Spanner-Ulmer, Birgit

    2012-01-01

    A field study in an automotive supply industry company was conducted to explore age-differentiated strain of assembly line workers. Subjective and objective data from 23 female workers aged between 27 and 57 years were collected at the workplace belt buckle assembly during morning shifts. Subjects with medication or chronic diseases affecting heart rate and breath rate were excluded. For subjective data generation different questionnaires were used. Before the Work Ability Index and the Munich Chronotype Questionnaire were completed by the subjects. Short questionnaires (strain-ratings, NASA-TLX) directly at begin and end of the work were used for obtaining shift-related data. During the whole shift (6 a.m. - 2.45 p.m.) bodily functions were logged with a wireless chest strap. In addition, the motion of the hand-arm-system was recorded for 30 times, 3 minutes each after a fixed time-schedule. First results show that younger subjects need significant less time for assembly (mean = 14.940 s) compared to older subjects (mean = 17.040 s; t(472.026) = -9.278 , p < 0.01).

  5. HF radar observations of Pc 5 field line resonances in the midnight/early morning MLT sector

    SciTech Connect

    Ruohoniemi, J.M.; Greenwald, R.A.; Baker, K.B. ); Samson, J.C. )

    1991-09-01

    On a number of occasions The Johns Hopkins University/Applied Physics Laboratory HF radar at Goose Bay, Labrador, has observed the effects of field line resonances on the drift velocities of irregularities in the F region of the high-latitude ionosphere. One of the most interesting sets of resonances occurs near midnight MLT and may be associated with shear in the convective flow in the magnetotail. This paper discusses in detail a particularly clear example which shows field line resonance equatorward of a region of shear flow in the early morning sector. The motions were predominantly in the geomagnetic east-west direction, indicating north-south electric fields. As expected of field line resonance pulsations, these oscillations had pronounced peaks in their latitudinal power distribution. The pulsations could occur simultaneously but remained distinct as the latitude of peak response was observed to vary inversely with the frequency of the pulsation. The authors interpret these features in terms of field line resonance theory and discuss the possible sources of the pulsation energy.

  6. Rotational Sweepback of Magnetic Field Lines in Geometrical Models of Pulsar Radio Emission

    NASA Technical Reports Server (NTRS)

    Dyks, J.; Harding, Alice K.

    2004-01-01

    We study the rotational distortions of the vacuum dipole magnetic field in the context of geometrical models of the radio emission from pulsars. We find that at low altitudes the rotation deflects the local direction of the magnetic field by at most an angle of the order of r(sup 2 sub n), where r(sub n) = r/R(sub lc), r is the radial distance and R(sub lc) is the light cylinder radius. To the lowest (i.e. second) order in r(sub n) this distortion is symmetrical with respect to the plane containing the dipole axis and the rotation axis ((Omega, mu) plane). The lowest order distortion which is asymmetrical with respect to the (Omega, mu) plane is third order in r(sub n). These results confirm the common assumption that the rotational sweepback has negligible effect on the position angle (PA) curve. We show, however, that the influence of the sweep back on the outer boundary of the open field line region (open volume) is a much larger effect, of the order of r(sup 1/2 sub n). The open volume is shifted backwards with respect to the rotation direction by an angle delta(sub o nu) approx. 0.2 sin alpha r(sup 1/2 sub n) where alpha is the dipole inclination with respect to the rotation axis. The associated phase shift of the pulse profile Delta phi(sub o nu) approx. 0.2 r(sup 1/2 sub n) can easily exceed the shift due to combined effects of aberration and propagation time delays (approx. 2r(sub n)). This strongly affects the misalignment of the center of the PA curve and the center of the pulse profile, thereby modifying the delay radius relation. Contrary to intuition, the effect of sweepback dominates over other effects when emission occurs at low altitudes. For r(sub n) < or approx. 3 x 10(exp -3) the shift becomes negative, i.e. the center of the position angle curve precedes the profile center. With the sweepback effect included, the modified delay-radius relation predicts larger emission radii and is in much better agreement with the other methods of determining r

  7. Phase transformations in aqueous low molar mass poly(vinyl methyl ether) solutions: theoretical prediction and experimental validation of the peculiar solvent melting line, bimodal LCST, and (adjacent) UCST miscibility gaps.

    PubMed

    Van Durme, Kurt; Van Assche, Guy; Nies, Erik; Van Mele, Bruno

    2007-02-15

    Supported by theoretical predictions based on the Wertheim Lattice Thermodynamic Perturbation Theory, modulated temperature differential scanning calorimetry (MTDSC) was used to further the knowledge of the phase behavior of aqueous poly(vinyl methyl ether) (PVME) solutions. Using a narrowly dispersed low molar mass PVME, we determined the following phase boundaries: (i) a bimodal lower critical solution temperature (LCST) miscibility gap at physiological temperature (around 37 degrees C), (ii) an upper critical solution temperature (UCST) two-phase area at sub-zero temperatures and high polymer concentration, and (iii) the melting line of the solvent across the entire concentration range, showing a peculiar stepwise decrease with composition. The location of the glass transition region and its influence on the crystallization/melting behavior of the solvent is discussed.

  8. Irreversibility Line Measurement and Vortex Dynamics in High Magnetic Fields in Ni- and Co-Doped Iron Pnictide Bulk Superconductors

    DOE PAGES

    Nikolo, Martin; Singleton, John; Zapf, Vivien S.; ...

    2016-07-20

    The de-pinning or irreversibility lines were determined by ac susceptibility, magnetization, radio-frequency proximity detector oscillator (PDO), and resistivity methods in Ba(Fe0.92Co0.08)2As2 ( Tc = 23.2 K), Ba(Fe0.95Ni0.05)2As2 ( Tc = 20.4 K), and Ba(Fe0.94Ni0.06)2As2 ( Tc = 18.5 K) bulk superconductors in ac, dc, and pulsed magnetic fields up to 65 T. A new method of extracting the irreversibility fields from the radio-frequency proximity detector oscillator induction technique is described. Wide temperature broadening of the irreversibility lines, for any given combination of ac and dc fields, is dependent on the time frame of measurement. Increasing the magnetic field sweep ratemore » (dH/dt) shifts the irreversibility lines to higher temperatures up to about dH/d t = 40,000 Oe/s; for higher dH/dt, there is little impact on the irreversibility line. There is an excellent data match between the irreversibility fields obtained from magnetization hysteresis loops, PDO, and ac susceptibility measurements, but not from resistivity measurements in these materials. Lower critical field vs. temperature phase diagrams are measured. Their very low values near 0 T indicate that these materials are in mixed state in nonzero magnetic fields, and yet the strength of the vortex pinning enables very high irreversibility fields, as high as 51 T at 1.5 K for the Ba(Fe0.92Co0.08)2As2 polycrystalline sample, showing a promise for liquid helium temperature applications.« less

  9. Researching of sea waves influence on a coastal line transformation (based on field observation results)

    NASA Astrophysics Data System (ADS)

    Chernov, A.; Kouznetsov, K.; Kurkin, A.; Shevchenko, G.

    2009-04-01

    The long duration registrations of bottom pressure, temperature and meteorological data took place in June - October 2007 on the shelf near 104th - 110th kilometer of interstate road Yuzhno-Sakhalinsk - Okha. Sediment transport and abrasion processes are observed in this place, it is a dangerous factor for road and railroad constructions, it can also be threat for some buildings of Vzmorie town. Distributed network of autonomous pressure gauges was installed for wave structure studying. Gauges were installed in tree lines with 100, 150 and 200 meters far from each other. Gathered data contains information about different wave's regimes under different weather conditions, it's allowed us to make analysis. Different data rows for different wave regimes were taken for analysis. Transformation of wave field along shoreline and opposite was observed. The results of observation are showed that disposition of waves was determined by swell waves with period 8-9 second. Wind waves were weaker than swell waves, conceivably because of big depths in the studied area. Much more interesting results were found in the infragravity waves range (0.5 - 5 min). For example, peaks with period above 150 and 75 seconds are presented in the spectral estimation of record from gauge 23. The same peaks were not observed in other gauges to the North and to the South from 23. However, low frequency peak was much stronger at the storm weather, but 75 seconds peak was stayed non-changed under the different weather conditions. For understanding mechanism of infra-gravitation waves generation group structure of waves were studied. Spectrum characteristics of different data rows for different wave regimes and also for their envelopes were provided. Results of this research allow us to consider that wave packets with common period 7 - 8 seconds make infra-gravitation waves with period above 5 minutes which forcing sediment transport processes. Satellite images of studied place were used in this

  10. Elastic line deformed on a surface by an external field: Intrinsic formulation and preliminary application to nucleosome energetics

    SciTech Connect

    Manning, G.S.

    1988-09-15

    If an elastically resilient thin rod (elastic line) is subjected to a static force field, it adopts a trajectory that minimizes the sum of its elastic energy and its energy of interaction with the field. Using ''intrinsic'' methods of differential geometry and variational calculus, we formulate and solve this problem for an elastic line confined to a general surface. The biological structure known as the nucleosome core particle provides motivation to apply the solution to an elastic line (DNA) subject to a centrosymmetric force emanating from a circle. In this case the surface is a plane (although the surface will be curved in a more accurate model). In preliminary numerical work we are able to represent the angular deviation of the elastic line to fifth order in powers of arc length. The result of greatest interest may be that the equilibrium trajectory appears not to approach the circle progressively with increasing strength of the attraction between line and circle. Instead, the line approaches a ''barrier'' trajectory and, as it does, becomes unstable relative to the circular arc.

  11. Coherent artifact suppression in line-field reflection confocal microscopy using a low spatial coherence light source.

    PubMed

    Liu, Changgeng; Cao, Hui; Choma, Michael A

    2016-10-15

    Line-field reflection confocal microscopy (LF-RCM) has the potential to add a dimension of parallelization to traditional confocal microscopy while reducing the need for two-axis beam scanning. LF-RCM systems often employ light sources with a high degree of spatial coherence. This high degree of spatial coherence potentially leads to unwanted coherent artifact in the setting of nontrivial sample scattering. Here, we (a) confirm that a coherent artifact is a nontrivial problem in LF-RCM when using spatially coherent light, and (b) demonstrate that such a coherent artifact can be mitigated through the use of reduced spatial coherence line-field sources. We demonstrate coherent noise suppression in a full-pupil line-field confocal microscope using a large number of mutually incoherent emitters from a vertical-cavity surface-emitting lasers (VCSEL) array. The coherent noise from a highly scattering sample is significantly suppressed by the use of this synthesized reduced spatial coherence light source compared to a fully coherent light source. Lastly, with scattering samples, the axial confocality of line-field confocal microscopy is compromised independent of the source spatial coherence, as demonstrated by our experimental result. Our results highlight the importance of spatial coherence engineering in parallelized reflection confocal microscopy.

  12. First in situ evidence of electron pitch angle scattering due to magnetic field line curvature in the Ion diffusion region

    NASA Astrophysics Data System (ADS)

    Zhang, Y. C.; Shen, C.; Marchaudon, A.; Rong, Z. J.; Lavraud, B.; Fazakerley, A.; Yao, Z.; Mihaljcic, B.; Ji, Y.; Ma, Y. H.; Liu, Z. X.

    2016-05-01

    Theory predicts that the first adiabatic invariant of a charged particle may be violated in a region of highly curved field lines, leading to significant pitch angle scattering for particles whose gyroradius are comparable to the radius of the magnetic field line curvature. This scattering generates more isotropic particle distribution functions, with important impacts on the presence or absence of plasma instabilities. Using magnetic curvature analysis based on multipoint Cluster spacecraft observations, we present the first investigation of magnetic curvature in the vicinity of an ion diffusion region where reconnected field lines are highly curved. Electrons at energies > 8 keV show a clear pitch angle ordering between bidirectional and trapped distribution in surrounding regions, while we show that in the more central part of the ion diffusion region electrons above such energies become isotropic. By contrast, colder electrons (~1 keV) retain their bidirectional character throughout the diffusion regions. The calculated adiabatic parameter K2 for these electrons is in agreement with theory. This study provides the first observational evidence for particle pitch angle scattering due to magnetic field lines with well characterized curvature in a space plasma.

  13. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... encirclement welded split sleeve of appropriate design, unless the transmission line is joined by mechanical... method that reliable engineering tests and analyses show can permanently restore the serviceability...

  14. 49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... encirclement welded split sleeve of appropriate design, unless the transmission line is joined by mechanical... method that reliable engineering tests and analyses show can permanently restore the serviceability...

  15. The hybrid reactor project based on the straight field line mirror concept

    NASA Astrophysics Data System (ADS)

    Ågren, O.; Noack, K.; Moiseenko, V. E.; Hagnestâl, A.; Källne, J.; Anglart, H.

    2012-06-01

    The straight field line mirror (SFLM) concept is aiming towards a steady-state compact fusion neutron source. Besides the possibility for steady state operation for a year or more, the geometry is chosen to avoid high loads on materials and plasma facing components. A comparatively small fusion hybrid device with "semi-poor" plasma confinement (with a low fusion Q factor) may be developed for industrial transmutation and energy production from spent nuclear fuel. This opportunity arises from a large fission to fusion energy multiplication ratio, Qr = Pfis/Pfus>>1. The upper bound on Qr is primarily determined by geometry and reactor safety. For the SFLM, the upper bound is Qr≈150, corresponding to a neutron multiplicity of keff=0.97. Power production in a mirror hybrid is predicted for a substantially lower electron temperature than the requirement Te≈10 keV for a fusion reactor. Power production in the SFLM seems possible with Q≈0.15, which is 10 times lower than typically anticipated for hybrids (and 100 times smaller than required for a fusion reactor). This relaxes plasma confinement demands, and broadens the range for use of plasmas with supra-thermal ions in hybrid reactors. The SFLM concept is based on a mirror machine stabilized by qudrupolar magnetic fields and large expander tanks beyond the confinement region. The purpose of the expander tanks is to distribute axial plasma loss flow over a sufficiently large area so that the receiving plates can withstand the heat. Plasma stability is not relying on a plasma flow into the expander regions. With a suppressed plasma flow into the expander tanks, a possibility arise for higher electron temperature. A brief presentation will be given on basic theory for the SFLM with plasma stability and electron temperature issues, RF heating computations with sloshing ion formation, neutron transport computations with reactor safety margins and material load estimates, magnetic coil designs as well as a discussion on

  16. A WFC3 Grism Emission Line Redshift Catalog in the GOODS-South Field

    NASA Astrophysics Data System (ADS)

    Morris, Aaron M.; Kocevski, Dale D.; Trump, Jonathan R.; Weiner, Benjamin J.; Hathi, Nimish P.; Barro, Guillermo; Dahlen, Tomas; Faber, Sandra M.; Finkelstein, Steven L.; Fontana, Adriano; Ferguson, Henry C.; Grogin, Norman A.; Grützbauch, Ruth; Guo, Yicheng; Hsu, Li-Ting; Koekemoer, Anton M.; Koo, David C.; Mobasher, Bahram; Pforr, Janine; Salvato, Mara; Wiklind, Tommy; Wuyts, Stijn

    2015-06-01

    We combine Hubble Space Telescope (HST)/Wide Field Camera3 (WFC3) imaging and G141 grism observations from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and 3D-HST surveys to produce a catalog of grism spectroscopic redshifts for galaxies in the CANDELS/GOODS-South field. The WFC3/G141 grism spectra cover a wavelength range of 1.1≤slant λ ≤slant 1.7 μm with a resolving power of R∼ 130 for point sources, thus providing rest-frame optical spectra for galaxies out to z∼ 3.5. The catalog is selected in the H-band (F160W) and includes both galaxies with and without previously published spectroscopic redshifts. Grism spectra are extracted for all H-band detected galaxies with H ≤slant 24 and a CANDELS photometric redshift {{z}phot}≥slant 0.6. The resulting spectra are visually inspected to identify emission lines, and redshifts are determined using cross-correlation with empirical spectral templates. To establish the accuracy of our redshifts, we compare our results against high-quality spectroscopic redshifts from the literature. Using a sample of 411 control galaxies, this analysis yields a precision of {{σ }NMAD}=0.0028 for the grism-derived redshifts, which is consistent with the accuracy reported by the 3D-HST team. Our final catalog covers an area of 153 arcmin2 and contains 1019 redshifts for galaxies in GOODS-S. Roughly 60% (608/1019) of these redshifts are for galaxies with no previously published spectroscopic redshift. These new redshifts span a range of 0.677≤slant z≤slant 3.456 and have a median redshift of z = 1.282. The catalog contains a total of 234 new redshifts for galaxies at z\\gt 1.5. In addition, we present 20 galaxy pair candidates identified for the first time using the grism redshifts in our catalog, including four new galaxy pairs at z∼ 2, nearly doubling the number of such pairs previously identified.

  17. Design of soft x-ray varied-line-spacing grating based on electron beam lithography-near field lithography

    NASA Astrophysics Data System (ADS)

    Lin, Dakui; Chen, Huoyao; Kroker, Stefanie; Käsebier, Thomas; Liu, Zhengkun; Qiu, Keqiang; Liu, Ying; Kley, Ernst-Bernhard; Xu, Xiangdong; Hong, Yilin; Fu, Shaojun

    2016-10-01

    Soft x-ray varied line spacing grating (VLSG), which is a vital optical element for laser plasma diagnosis and spectrometry analysis, is conventionally fabricated by holographic lithography or mechanical ruling. In order to overcome the issues of the above fabrication methods, a method based on electron beam lithography-near field lithography (EBL-NFH) is proposed to make good use of the flexibility of EBL and the high throughput of NFH. In this paper, we showed a newly designed soft x-ray VLSG with a central groove density of 3600 lines/mm, which is to be realized based on EBL-NFH. First, the optimization of the spatial distribution of line density and groove profile of the VLSG was shown. As an important element in NFH, a fused silica mask plays a key role during NFH in order to obtain a required line density of VLSG. Therefore, second, the transfer relationship of spatial distribution of line densities between fused silica mask and resist grating was investigated in different exposure modes during NFH. We proposed a formulation about the transfer of line density to design of the groove density distribution of a fused silica grating mask. Finally, the spatial distribution of line densities between the fused silica mask, which is to be fabrication by using EBL, was demonstrated.

  18. Greenhouse and Field Evaluation of Multiple Virus Resistant Lagenaria siceraria Lines Potentially useful for Watermelon Rootstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In previous evaluations we identified numerous lines of bottle gourd (Lagenaria siceraria) with complete or partial resistance to Zucchini yellow mosaic virus (ZYMV). In the present study, we were interested in developing bottle gourd lines with multiple virus resistance that could be useful as roo...

  19. Field data and numerical modeling: A multiple lines of evidence approach for assessing vapor intrusion exposure risks.

    PubMed

    Pennell, Kelly G; Scammell, Madeleine K; McClean, Michael D; Suuberg, Eric M; Moradi, Ali; Roghani, Mohammadyousef; Ames, Jennifer; Friguglietti, Leigh; Indeglia, Paul A; Shen, Rui; Yao, Yijun; Heiger-Bernays, Wendy J

    2016-06-15

    USEPA recommends a multiple lines of evidence approach to make informed decisions at vapor intrusion sites because the vapor intrusion pathway is notoriously difficult to characterize. Our study uses this approach by incorporating groundwater, soil gas, indoor air field measurements and numerical models to evaluate vapor intrusion exposure risks in a Metro-Boston neighborhood known to exhibit lower than anticipated indoor air concentrations based on groundwater concentrations. We collected and evaluated five rounds of field sampling data over the period of one year. Field data results show a steep gradient in soil gas concentrations near the groundwater surface; however as the depth decreases, soil gas concentration gradients also decrease. Together, the field data and the numerical model results suggest that a subsurface feature is limiting vapor transport into indoor air spaces at the study site and that groundwater concentrations are not appropriate indicators of vapor intrusion exposure risks in this neighborhood. This research also reveals the importance of including relevant physical models when evaluating vapor intrusion exposure risks using the multiple lines of evidence approach. Overall, the findings provide insight about how the multiple lines of evidence approach can be used to inform decisions by using field data collected using regulatory-relevant sampling techniques, and a well-established 3-D vapor intrusion model.

  20. A Field Study of Lightning Overvoltages on Low-voltage Distribution Lines

    NASA Astrophysics Data System (ADS)

    Ishii, Tsunayoshi; Oguchi, Syuichi; Sakamoto, Yoshiki; Okabe, Shigemitsu

    Recently, the number of home electric appliances, such as personal computers and telephones, is rapidly increased. Lightning damage to these home electric appliances has a great impact on highly sophisticated information society. There are some cases that lightning overvoltages on low-voltage distribution lines cause malfunction of them, though they equipped surge protective devices to protect against lightning overvoltages. Therefore, for lightning protection of low-voltage equipments including home electric appliances, it's important to understand the phenomenon of lightning overvoltages on low-voltage distribution lines. However, it's not so clear including the generation of them. The Tokyo Electric Power Company carries out the lightning observation on low-voltage distribution lines. The observation results provide the statistical distribution of lightning overvoltages on low-voltage distribution lines. The generation mechanism of lightning overvoltages on low-voltage distribution lines is assumed based on observed waveforms and facilities data.

  1. New operating strategies for molten salt in line focusing solar fields - Daily drainage and solar receiver preheating

    NASA Astrophysics Data System (ADS)

    Eickhoff, Martin; Meyer-Grünefeldt, Mirko; Keller, Lothar

    2016-05-01

    Nowadays molten salt is efficiently used in point concentrating solar thermal power plants. Line focusing systems still have the disadvantage of elevated heat losses at night because of active freeze protection of the solar field piping system. In order to achieve an efficient operation of line focusing solar power plants using molten salt, a new plant design and a novel operating strategy is developed for Linear Fresnel- and Parabolic Trough power plants. Daily vespertine drainage of the solar field piping and daily matutinal refilling of the solar preheated absorber tubes eliminate the need of nocturnal heating of the solar field and reduce nocturnal heat losses to a minimum. The feasibility of this new operating strategy with all its sub-steps has been demonstrated experimentally.

  2. An examination of underlying physical principles. The interaction of power-line electromagnetic fields with the human body.

    PubMed

    King, R W

    1998-01-01

    A detailed examination of the scientific foundations contained in a number of recent articles has revealed some serious errors. The careful application of advanced mathematical-physical methods to study the penetration of externally applied electric fields into the organs and cells of the human body has obtained new and significant results [8, 9, 32]. Specifically, Eqs. (11) and (12) establish a definite relationship between an incident low-frequency electric field and the current, current density, and electric field induced in the body when the arms are in contact with it and the incident field is parallel to its length. Corresponding formulas with the arms raised are available [10] as are formulas for the current density and electric field in the organs of the body [9]. It is these currents and electric fields that must be used by biomedical research workers to determine their effect on living cells. The proposed interpretation of epidemiological data [31] indicates a risk of leukemia in children when the incident 50-60-Hz electric field generated by a high-voltage transmission line is Einc > or = 61 V/m. (23). The corresponding maximum electric field at approximately 10 m from a 440-kV transmission line is Einc approximately 2100 V/m [8, 9]. The electric fields induced in the different organs of the body by these electric fields are in the range 25.2 < or = E1z < or = 119 microV/m for Einc2z = 61 V/m and 0.87 < or = E1z < or = 4.1 mV/m for Einc2z = 2100 V/m [9]. These are in the range of applied fields in in vitro experiments, which showed significant effects on cells [4], and should serve as guidelines for such experiments.

  3. The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Search for [CII] Line and Dust Emission in 6

    NASA Astrophysics Data System (ADS)

    Aravena, M.; Decarli, R.; Walter, F.; Bouwens, R.; Oesch, P. A.; Carilli, C. L.; Bauer, F. E.; Da Cunha, E.; Daddi, E.; Gónzalez-López, J.; Ivison, R. J.; Riechers, D. A.; Smail, I.; Swinbank, A. M.; Weiss, A.; Anguita, T.; Bacon, R.; Bell, E.; Bertoldi, F.; Cortes, P.; Cox, P.; Hodge, J.; Ibar, E.; Inami, H.; Infante, L.; Karim, A.; Magnelli, B.; Ota, K.; Popping, G.; van der Werf, P.; Wagg, J.; Fudamoto, Y.

    2016-12-01

    We present a search for [C ii] line and dust continuum emission from optical dropout galaxies at z > 6 using ASPECS, our Atacama Large Millimeter submillimeter Array Spectroscopic Survey in the Hubble Ultra-deep Field (UDF). Our observations, which cover the frequency range of 212-272 GHz, encompass approximately the range of 6 < z < 8 for [C ii] line emission and reach a limiting luminosity of L [C ii] ˜ (1.6-2.5) × 108 L ⊙. We identify 14 [C ii] line emitting candidates in this redshift range with significances >4.5σ, two of which correspond to blind detections with no optical counterparts. At this significance level, our statistical analysis shows that about 60% of our candidates are expected to be spurious. For one of our blindly selected [C ii] line candidates, we tentatively detect the CO(6-5) line in our parallel 3 mm line scan. None of the line candidates are individually detected in the 1.2 mm continuum. A stack of all [C ii] candidates results in a tentative detection with S 1.2 mm = 14 ± 5 μJy. This implies a dust-obscured star-formation rate (SFR) of (3 ± 1) M ⊙ yr-1. We find that the two highest-SFR objects have candidate [C ii] lines with luminosities that are consistent with the low-redshift L [C ii] versus SFR relation. The other candidates have significantly higher [C ii] luminosities than expected from their UV-based SFR. At the current sensitivity, it is unclear whether the majority of these sources are intrinsically bright [C ii] emitters, or spurious sources. If only one of our line candidates was real (a scenario greatly favored by our statistical analysis), we find a source density for [C ii] emitters at 6 < z < 8 that is significantly higher than predicted by current models and some extrapolations from galaxies in the local universe.

  4. Depth and all-in-focus images obtained by multi-line-scan light-field approach

    NASA Astrophysics Data System (ADS)

    Štolc, Svorad; Huber-Mörk, Reinhold; Holländer, Branislav; Soukup, Daniel

    2014-03-01

    We present a light-field multi-line-scan image acquisition and processing system intended for the 2.5/3-D inspection of fine surface structures, such as small parts, security print, etc. in an industrial environment. The system consists of an area-scan camera, that allows for a small number of sensor lines to be extracted at high frame rates, and a mechanism for transporting the inspected object at a constant speed. During the acquisition, the object is moved orthogonally to the camera's optical axis as well as the orientation of the sensor lines. In each time step, a predefined subset of lines is read out from the sensor and stored. Afterward, by collecting all corresponding lines acquired over time, a 3-D light field is generated, which consists of multiple views of the object observed from different viewing angles while transported w.r.t. the acquisition device. This structure allows for the construction of so-called epipolar plane images (EPIs) and subsequent EPI-based analysis in order to achieve two main goals: (i) the reliable estimation of a dense depth model and (ii) the construction of an all-in-focus intensity image. Beside specifics of our hardware setup, we also provide a detailed description of algorithmic solutions for the mentioned tasks. Two alternative methods for EPI-based analysis are compared based on artificial and real-world data.

  5. Assessment of electromagnetic field levels from surrounding high-tension overhead power lines for proposed land use.

    PubMed

    Al-Bassam, E; Elumalai, A; Khan, A; Al-Awadi, L

    2016-05-01

    The surrounding outdoor environment for new development has a big effect on the indoor quality of life. The main aim of this work was to determine the suitability of the area for building new schools with reference to electromagnetic field (EMF) effects. The specific objective of this study was to detect the safe distance from the EMF posed by the high-tension overhead power lines in the vicinity of the specified area. The measurements were taken for both the electric and magnetic fields in different months in order to detect the highest EMF levels during the peak power load season. EMDEX II with E-probe and EMDEX II with Linda were used for the measurements. These instruments were all calibrated by ENERTECH Company in USA. The EMF associated with high tension transmission lines that surrounded the proposed site has to be below 0.2 μT (Italian EMF regulations are the most suitable regulations for the establishment of schools in Kuwait). The safety clearance distance from the existing 300-kV high-tension power line has been assigned as 200 m and from other existing 132-kV high-tension power line was 50 m. The proposed site with its predefined boundaries has a magnetic field below the Italian EMF regulations for the establishment of new schools.

  6. High-voltage overhead power lines in epidemiology: patterns of time variations in current load and magnetic fields.

    PubMed

    Reitan, J B; Tynes, T; Kvamshagen, K A; Vistnes, A I

    1996-01-01

    In epidemiological studies of electromagnetic fields and health effects, exposure classification is crucial. There is no generally accepted biophysical interaction mechanism, but many studies are based on the hypothesis of a causal relationship with the strength of magnetic field. Some definition of the magnitude of exposure must be used, e.g., mean magnetic flux density, the integral of magnetic flux and time, or a peak value. Magnetic fields around a particular power line depend on the current load. The aim of the present study was to follow variations in line current load in the power supply system of the largest Norwegian city on a yearly, monthly, daily and diurnal basis. Fairly large variations in load were found, but increases in consumption were not necessarily reflected in current load on high voltage lines. The correlation between outdoor temperature and current load varied widely, depending on the type of power station feeding the line in question. The registered time variations are large enough to interfere with epidemiological classification of residences and testing of epidemiological hypotheses.

  7. Temperature and field dependence of the flux-line-lattice symmetry in V{sub 3}Si

    SciTech Connect

    Yethiraj, M.; Christen, D.K.; Gapud, A.A.; Paul, D. McK.; Crowe, S.J.; Dewhurst, C.D.; Cubitt, R.; Porcar, L.; Gurevich, A.

    2005-08-01

    In V{sub 3}Si, a first-order structural phase transition from hexagonal to square flux-line lattice occurs at approximately 1 T with H parallel to the a axis. In this paper, we demonstrate the reentrant structural transition in the flux-line lattice, which reverts to hexagonal symmetry as the magnetic field approached H{sub c2}(T). This behavior is described very well by a nonlocal London theory with thermal fluctuations. The phase diagram of the flux lattice topology is mapped out for this geometry.

  8. A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Lens Environments and Line-of-Sight Structures

    NASA Astrophysics Data System (ADS)

    Wilson, Michelle; Zabludoff, Ann I.; Wong, Kenneth C.; Keeton, Charles R.; French, Katheryn Decker; Momcheva, Ivelina G.; Williams, Kurtis A.

    2016-01-01

    Galaxy-scale strong gravitational lensing has long been used to measure cosmological parameters such as the Hubble constant as well as the dark matter properties of galaxy halos. Additional mass around the lens galaxy or projected in the line-of-sight affects the light bending and needs to be incorporated into lensing analyses. We present new results from a spectroscopic survey to characterize the environmental and line-of-sight mass for 28 galaxy-scale lens fields. We show how the external convergence, number of lensed images, and lensed image separation are altered by groups at the lens and along the sightline.

  9. A marching method for calculating line and continuum radiation in high energy flow fields

    NASA Technical Reports Server (NTRS)

    Bolz, C. W., Jr.

    1979-01-01

    A method is presented for calculating nongrey radiative fluxes and intensities in a highly ionized, low temperature plasma with extreme line broadening. The method was developed to study radiative heating phenomena in the mass-injected hypersonic shock-layer environments characteristic of outer planet atmospheric entry, although it is not limited to such studies. The radiative properties model assumed local thermodynamic equilibrium and used standard continuum and molecular band models. The atomic line model, however, used a frequency-marching method for the frequency integration, which not only accounted completely for line overlapping (reabsorption) effects, but compared favorably in economy with the best equivalent-width methods. An assessment of hydrogen line-far-wing treatments, with recommendations for engineering models, is also presented.

  10. Subexponential Divergence and Diffusive Twist of Turbulent Magnetic Field Lines in the Limit of the Very Short Separations

    NASA Astrophysics Data System (ADS)

    Ragot, B. R.

    2008-08-01

    Turbulent magnetic field lines have long been thought to be diverging from each other (or converging toward each other) at exponential rates known as Lyapunov exponents. It is argued here that in a turbulent magnetized plasma, subexponential divergence (convergence) and diffusive twist better characterize the dispersal of magnetic field lines (MFLs) in the limit of the very small separations ρ than do the usual Lyapunov exponents or exponentiation rates. In that limit of the very small separations, the field-line equations give a variation rate for ln ρ , not ρ, and the implied log-normality of the ρ distribution makes langle (ln ρ/ρ0)2rangle a much better probe of the exponential divergence of core MFLs. A fully nonlinear calculation shows that the separation logarithm, ln ρ , and twist or rotation angle, Δ θ , between pairs of MFLs diffuse with the distance Δ z elapsed along the main field, as soon as Δ z exceeds min (k-1II,ζII) , the minimum of the parallel correlation length k-1II ≡ L∥ ∇ of the turbulent field gradients and of the associated nonlinear scale, ζII ≡ ζ∇, defined as the field-aligned length scale for which the mean cross-field displacement langle (rζ - r0)2rangle1/2 reaches 21/2ξ k-1II ≡ 21/2L⊥ ∇, with kII the wavenumber where the turbulence spectrum becomes steeper than (k2∥ + ξ2k2⊥)-1 and ξ the anisotropy parameter of the turbulence. The average growth of the core field-line separation ρ0elangle (ln ρ/ρ0)2rangle1/2 = epropto (Δ z)1/2 along the direction of fastest growth, being subexponential, is not compatible with the definition of Lyapunov exponents. The largest exponentiation rate of the core MFLs actually decreases with the distance Δ z. Application of the new nonlinear calculation to the solar wind shows a substantial MFL rotation in a plane transverse to the main field.

  11. Improved phase sensitivity in spectral domain phase microscopy using line-field illumination and self phase-referencing

    PubMed Central

    Yaqoob, Zahid; Choi, Wonshik; Oh, Seungeun; Lue, Niyom; Park, Yongkeun; Fang-Yen, Christopher; Dasari, Ramachandra R.; Badizadegan, Kamran; Feld, Michael S.

    2010-01-01

    We report a quantitative phase microscope based on spectral domain optical coherence tomography and line-field illumination. The line illumination allows self phase-referencing method to reject common-mode phase noise. The quantitative phase microscope also features a separate reference arm, permitting the use of high numerical aperture (NA > 1) microscope objectives for high resolution phase measurement at multiple points along the line of illumination. We demonstrate that the path-length sensitivity of the instrument can be as good as 41 pm/Hz, which makes it suitable for nanometer scale study of cell motility. We present the detection of natural motions of cell surface and two-dimensional surface profiling of a HeLa cell. PMID:19550464

  12. The effects of magnetic fringe fields on beam dynamics in a beam transport line of a terahertz FEL source

    NASA Astrophysics Data System (ADS)

    Zeng, Han; Xiong, Yongqian; Pei, Yuanji

    2014-11-01

    The transport line used in a terahertz FEL device has to transport electron beam through the entire system efficiently and meet the requirements of the beam parameters at the undulator entrance. Due to space limitations, the size of the magnets (five quadrupoles and two bending magnets) employed in the transport line was limited, and some devices were densely packed. In this paper, analyses of the effect of fringe fields and magnetic interference of magnets are presented. 3D models of these magnets are built and their linear optical properties are compared with those obtained by hard edge models. The results indicated that the effects of these factors are significant and they would cause a mismatch of the beam at the exit of the transport line under the preliminary lattice design. To solve this problem, the beam was re-matched using the particle swarm optimization algorithm.

  13. Full-zone spectral envelope function formalism for the optimization of line and point tunnel field-effect transistors

    SciTech Connect

    Verreck, Devin Groeseneken, Guido; Verhulst, Anne S.; Mocuta, Anda; Collaert, Nadine; Thean, Aaron; Van de Put, Maarten; Magnus, Wim; Sorée, Bart

    2015-10-07

    Efficient quantum mechanical simulation of tunnel field-effect transistors (TFETs) is indispensable to allow for an optimal configuration identification. We therefore present a full-zone 15-band quantum mechanical solver based on the envelope function formalism and employing a spectral method to reduce computational complexity and handle spurious solutions. We demonstrate the versatility of the solver by simulating a 40 nm wide In{sub 0.53}Ga{sub 0.47}As lineTFET and comparing it to p-n-i-n configurations with various pocket and body thicknesses. We find that the lineTFET performance is not degraded compared to semi-classical simulations. Furthermore, we show that a suitably optimized p-n-i-n TFET can obtain similar performance to the lineTFET.

  14. Emission-Line Galaxies from the PEARS Hubble Ultra Deep Field: A 2-D Detection Method and First Results

    NASA Technical Reports Server (NTRS)

    Gardner, J. P.; Straughn, Amber N.; Meurer, Gerhardt R.; Pirzkal, Norbert; Cohen, Seth H.; Malhotra, Sangeeta; Rhoads, james; Windhorst, Rogier A.; Gardner, Jonathan P.; Hathi, Nimish P.; Xu, Chun; Gronwall, Caryl; Koekemoer, Anton M.; Walsh, Jeremy; diSeregoAlighieri, Sperello

    2007-01-01

    The Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) grism PEARS (Probing Evolution And Reionization Spectroscopically) survey provides a large dataset of low-resolution spectra from thousands of galaxies in the GOODS North and South fields. One important subset of objects in these data are emission-line galaxies (ELGs), and we have investigated several different methods aimed at systematically selecting these galaxies. Here we present a new methodology and results of a search for these ELGs in the PEARS observations of the Hubble Ultra Deep Field (HUDF) using a 2D detection method that utilizes the observation that many emission lines originate from clumpy knots within galaxies. This 2D line-finding method proves to be useful in detecting emission lines from compact knots within galaxies that might not otherwise be detected using more traditional 1D line-finding techniques. We find in total 96 emission lines in the HUDF, originating from 81 distinct "knots" within 63 individual galaxies. We find in general that [0 1111 emitters are the most common, comprising 44% of the sample, and on average have high equivalent widths (70% of [0 1111 emitters having rest-frame EW> 100A). There are 12 galaxies with multiple emitting knots; several show evidence of variations in H-alpha flux in the knots, suggesting that the differing star formation properties across a single galaxy can in general be probed at redshifts approximately greater than 0.2 - 0.4. The most prevalent morphologies are large face-on spirals and clumpy interacting systems, many being unique detections owing to the 2D method described here, thus highlighting the strength of this technique.

  15. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  16. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  17. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  18. 46 CFR 148.445 - Adjacent spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Adjacent spaces. 148.445 Section 148.445 Shipping COAST... THAT REQUIRE SPECIAL HANDLING Additional Special Requirements § 148.445 Adjacent spaces. When... following requirements must be met: (a) Each space adjacent to a cargo hold must be ventilated by...

  19. Magnetic Reconnection: studies of collisionless momentum balance near an X-line with a guide magnetic field

    NASA Astrophysics Data System (ADS)

    Fox, William; Egedal, J.; Porkolab, M.; Plasma Science, Mit; Center, Fusion

    2004-11-01

    A long-standing problem in reconnection research is what provides balance for the reconnecting electric field along an X-line. Two different types of theories can account for momentum balance: turbulence theories invoke unstable waves which provide a non-linear force on the particle species, and laminar models invoke terms in the momentum equation which are typically subdominant, such as electron inertia. For a laminar theory with a strong guide field, we present a study of all these tems, and a kinetic study where we have relaxed the condition that the X-line must be a stagnation point of the reconnection plasma flow, i.e. we construct solutions with plasma flow across, not just into and out of, the X-line. We present experimental evidence from the VTF open cusp configuration that the X-line is indeed not a stagnation point, and discuss consequences for momentum balance. Second, we present the first measurements of plasma turbulence in the new VTF closed configuration and discuss their relevance for momentum balance. This work was funded by an Oak Ridge Fusion Energy Sciences Fellowship, and by NSF/DoE Award DE-FG02-03ER54712

  20. Magnetic and Electric Field Diagnostics of Chromospheric Jets by Spectropolarimetric Observations of the HI Paschen Lines

    NASA Astrophysics Data System (ADS)

    Anan, T.; Casini, R.; Ichimoto, K.

    2014-10-01

    In order to study the magnetic and electric fields of chromospheric jets, we observed the full Stokes spectra of the Paschen series of neutral hydrogen in active region jets that took place at the solar limb on May 5, 2012. For the observations, we used the spectropolarimeter of the Domeless Solar Telescope at Hida observatory, Japan. Inversion of the Stokes spectra taking into account the effect of magnetic field on the energy structure and polarization of the hydrogen levels (including the Hanle effect and level-crossing effects) elucidates the magnetic field approximately aligned with the visible structure of the jets. In addition to the magnetic field, the energy structure and the polarization of the hydrogen levels is sensitive to electric field through the Stark effect, electric Hanle effect (analogous effect with the Hanle effect by magnetic field), and the level-crossing effects. Since, we found no definitive evidence of the polarization produced by the effect of electric field in the observed Stokes profiles, we derived upper limits of electric field felt by neutral atom moving across the magnetic field, and conclude that the velocity of the neutral atom perpendicular to the magnetic field was below several percents of the velocity bulk plasma motion.

  1. Performance of sheath electric field measurement by saturation spectroscopy in Balmer-α line of atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Nishiyama, Shusuke; Katayama, Kento; Nakano, Haruhisa; Goto, Motoshi; Sasaki, Koichi

    2017-03-01

    We developed a diode laser-based system for measuring the sheath electric fields in low-temperature plasmas. The Stark spectrum of the Balmer-α line of atomic hydrogen was measured by saturation spectroscopy with a fine spectral resolution. The spectrum observed experimentally was consistent with the theoretical Stark spectrum, and we succeeded in evaluating the electric field strength on the basis of the experimental Stark spectrum. A sensitive detection limit of 10 V/cm was achieved by the developed system.

  2. Irreversibility Line Measurement and Vortex Dynamics in High Magnetic Fields in Ni- and Co-Doped Iron Pnictide Bulk Superconductors

    SciTech Connect

    Nikolo, Martin; Singleton, John; Zapf, Vivien S.; Jiang, Jianyi; Weiss, Jeremy D.; Hellstrom, Eric E.

    2016-07-20

    The de-pinning or irreversibility lines were determined by ac susceptibility, magnetization, radio-frequency proximity detector oscillator (PDO), and resistivity methods in Ba(Fe0.92Co0.08)2As2 ( Tc = 23.2 K), Ba(Fe0.95Ni0.05)2As2 ( Tc = 20.4 K), and Ba(Fe0.94Ni0.06)2As2 ( Tc = 18.5 K) bulk superconductors in ac, dc, and pulsed magnetic fields up to 65 T. A new method of extracting the irreversibility fields from the radio-frequency proximity detector oscillator induction technique is described. Wide temperature broadening of the irreversibility lines, for any given combination of ac and dc fields, is dependent on the time frame of measurement. Increasing the magnetic field sweep rate (dH/dt) shifts the irreversibility lines to higher temperatures up to about dH/d t = 40,000 Oe/s; for higher dH/dt, there is little impact on the irreversibility line. There is an excellent data match between the irreversibility fields obtained from magnetization hysteresis loops, PDO, and ac susceptibility measurements, but not from resistivity measurements in these materials. Lower critical field vs. temperature phase diagrams are measured. Their very low values near 0 T indicate that these materials are in mixed state in nonzero magnetic fields, and yet the strength of the vortex pinning enables very high irreversibility fields, as high as 51 T at 1.5 K for the Ba(Fe0.92Co0.08)2As2 polycrystalline sample, showing a promise for liquid helium temperature applications.

  3. Ubiquity of chaotic magnetic-field lines generated by three-dimensionally crossed wires in modern electric circuits.

    PubMed

    Hosoda, M; Miyaguchi, T; Imagawa, K; Nakamura, K

    2009-12-01

    We investigate simple three-dimensionally crossed wires carrying electric currents which generate chaotic magnetic-field lines (CMFLs). As such wire systems, cross-ring and perturbed parallel-ring wires are studied, since topologically equivalent configurations to these systems can often be found in contemporary electric and integrated circuits. For realistic fundamental wire configurations, the conditions for wire dimensions (size) and current values to generate CMFLs are numerically explored under the presence of the weak but inevitable geomagnetic field. As a result, it is concluded that CMFLs can exist everywhere; i.e., they are ubiquitous in the modern technological world.

  4. Modeling the Pulse Line Ion Accelerator (PLIA): an algorithm for quasi-static field solution.

    SciTech Connect

    Friedman, A; Briggs, R J; Grote, D P; Henestroza, E; Waldron, W L

    2007-06-18

    The Pulse-Line Ion Accelerator (PLIA) is a helical distributed transmission line. A rising pulse applied to the upstream end appears as a moving spatial voltage ramp, on which an ion pulse can be accelerated. This is a promising approach to acceleration and longitudinal compression of an ion beam at high line charge density. In most of the studies carried out to date, using both a simple code for longitudinal beam dynamics and the Warp PIC code, a circuit model for the wave behavior was employed; in Warp, the helix I and V are source terms in elliptic equations for E and B. However, it appears possible to obtain improved fidelity using a ''sheath helix'' model in the quasi-static limit. Here we describe an algorithmic approach that may be used to effect such a solution.

  5. CONTINUUM INTENSITY AND [O i] SPECTRAL LINE PROFILES IN SOLAR 3D PHOTOSPHERIC MODELS: THE EFFECT OF MAGNETIC FIELDS

    SciTech Connect

    Fabbian, D.; Moreno-Insertis, F. E-mail: fmi@iac.es

    2015-04-01

    The importance of magnetic fields in three-dimensional (3D) magnetoconvection models of the Sun’s photosphere is investigated in terms of their influence on the continuum intensity at different viewing inclination angles and on the intensity profile of two [O i] spectral lines. We use the RH numerical radiative transfer code to perform a posteriori spectral synthesis on the same time series of magnetoconvection models used in our publications on the effect of magnetic fields on abundance determination. We obtain a good match of the synthetic disk-center continuum intensity to the absolute continuum values from the Fourier Transform Spectrometer (FTS) observational spectrum; the match of the center-to-limb variation synthetic data to observations is also good, thanks, in part, to the 3D radiation transfer capabilities of the RH code. The different levels of magnetic flux in the numerical time series do not modify the quality of the match. Concerning the targeted [O i] spectral lines, we find, instead, that magnetic fields lead to nonnegligible changes in the synthetic spectrum, with larger average magnetic flux causing both of the lines to become noticeably weaker. The photospheric oxygen abundance that one would derive if instead using nonmagnetic numerical models would thus be lower by a few to several centidex. The inclusion of magnetic fields is confirmed to be important for improving the current modeling of the Sun, here in particular in terms of spectral line formation and of deriving consistent chemical abundances. These results may shed further light on the still controversial issue regarding the precise value of the solar oxygen abundance.

  6. Solar Energetic Electron Probes of Magnetic Cloud Field Line Lengths (Postprint)

    DTIC Science & Technology

    2012-03-02

    clouds (MCs) are large interplanetary coronal mass ejections of enhanced and low‐variance fields with rotations indicative of magnetic flux ropes...published 21 January 2011. [1] Magnetic clouds (MCs) are large interplanetary coronal mass ejections of enhanced and low‐variance fields with...enhanced magnetic field strengths, and ( 3 ) low proton temperatures and low proton b. They compose about one quarter of all inter- planetary CMEs (ICMEs

  7. VIMOS integral field spectroscopy of blue compact galaxies. I. Morphological properties, diagnostic emission-line ratios, and kinematics

    NASA Astrophysics Data System (ADS)

    Cairós, L. M.; Caon, N.; Weilbacher, P. M.

    2015-05-01

    Context. Blue compact galaxies (BCG) are gas-rich, low-luminosity, low-metallicity systems that undergo a violent burst of star formation. These galaxies offer us a unique opportunity to investigate collective star formation and its effects on galaxy evolution in a relatively simple environment. Spatially resolved spectrophotometric studies of BCGs are essential for a better understanding of the role of starburst-driven feedback processes on the kinematical and chemical evolution of low-mass galaxies near and far. Aims: We carry out an integral field spectroscopic study of a sample of BCGs, with the aim of probing the morphology, kinematics, dust extinction, and excitation mechanisms of their warm interstellar medium. Methods: Eight BCGs were observed with the VIMOS integral field unit at the Very Large Telescope using blue and orange grisms in high-resolution mode. At a spatial sampling of 0''&dotbelow;67 per spaxel, we covered about 30″ × 30″ on the sky, with a wavelength range of 4150...7400 Å. Emission lines were fitted with a single Gaussian profile to measure their wavelength, flux, and width. From these data we built two-dimensional maps of the continuum and the most prominent emission-lines, as well as diagnostic line ratios, extinction, and kinematic maps. Results: An atlas has been produced with the following: emission-line fluxes and continuum emission; ionization, interstellar extinction, and electron density maps from line ratios; velocity and velocity dispersion fields. From integrated spectroscopy, it includes tables of the extinction corrected line fluxes and equivalent widths, diagnostic-line ratios, physical parameters, and the abundances for the brightest star-forming knots and for the whole galaxy. Based on observations made with ESO Telescopes at the Paranal Observatory under program ID 079.B-0445.The reduced datacubes and their error maps (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp

  8. RISK ASSESSMENT ANALYSES USING EPA'S ON-LINE SITE-SPECIFIC TRANSPORT MODELS AND FIELD DATA

    EPA Science Inventory

    EPA has developed a suite of on-line calculators and transport models to aid in risk assessment for subsurface contamination. The calculators (www.epa.gov/athens/onsite) provide several levels of tools and data. These include tools for generating commonly-used model input param...

  9. Hybridization of downregulated-COMT transgenic switchgrass lines with field selected switchgrass for improved biomass traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic switchgrass (Panicum virgatum L.) has been produced for improved cell walls for biofuels. Downregulated caffeic acid 3-O-methyltransferase (COMT) switchgrass produced significantly more biomass and biofuel than the non-transgenic progenitor line. In the present study we sought to further...

  10. Conversion of the 6302 / 6301 Stokes V Line Ratio to the 5250 / 5247 Ratio for the Diagnostics of Quiet-Sun Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Demidov, M. L.; Stenflo, J. O.; Bianda, M.; Ramelli, R.

    2014-10-01

    Observations in the "green" spectral lines Fe I 5247.06 and 5250.22 Å and in the "red" lines Fe I 6301.50 and 6302.50 Å are widely used to explore the properties of solar magnetic fields. The green line pair was introduced in 1973 as part of the line-ratio technique, which has been a powerful tool for investigations of intrinsic magnetic field properties at spatially unresolved scales (magnetic flux tubes with kG strengths). The red line pair has recently played a major role for magnetic-field diagnostics due to the large amount of high-quality data provided by the Hinode space observatory. These red lines however differ not only in the values of their Landé factors, but also in their line-formation properties, with the consequence that the magnetic-field information in their line ratio gets tangled up with thermodynamic effects. In contrast, as the green Fe I 5247.06 and 5250.22 Å lines differ only in their Landé factors, the magnetic field effects become cleanly separated from the thermodynamics, which allows the intrinsic magnetic field parameters to be extracted without ambiguties. The red and green line-ratio values are however statistically correlated. By determining the statistical regression function that relates them, it becomes possible to convert the "contaminated" and ambiguous red line ratio into the green line ratio, with which a reliable direct interpretation in terms of intrinsic field strengths is possible. To determine how the two line ratios are related we have made Stokesmeter observations in these four spectral lines with two solar instruments equipped with high-precision spectropolarimeters, ZIMPOL-3 at IRSOL (Locarno, Switzerland), and the STOP telescope at the Sayan Solar Observatory (Irkutsk, Russia). Most of the obtained results are based on IRSOL observations of quiet-sun magnetic fields. In the case of STOP the full-disk magnetograms of large-scale solar magnetic fields are analyzed. A major advantage at IRSOL is the possibility to

  11. LY-alpha Line Emission in a Field of Super-Clustered Damped LY-alpha Absorbers

    NASA Astrophysics Data System (ADS)

    Møller, Palle; Warren, Stephen J.

    1993-12-01

    The quasar pair Q2138-4427 and Q2139-4434 is separated by 8 arcmin on the sky (~ 6 Mpc), and they have correlated damped \\lya absorption (DLA) at two redshifts, z=2.380 and z=2.853 (Francis, P. J., and Hewett, P. C., 1993, AJ 105, 1633). On three nights in September 1993 we imaged the field of Q2138-4427 in B, I, and a narrow band tuned to the DLA at z=2.853. The observations were carried out with the ESO 3.6m telescope. We find two emission line candidates in the field. The two candidates have line fluxes similar to the three sources found in the field of Q0528-250 (M{\\o}ller, P., and Warren, S. J., 1993, \\aa 270, 43) but they are much brighter in the continuum. The two candidates are lying quite far from the quasar, so even if they are spectroscopically confirmed to be \\lya emitters, they are unlikely to be identified with the absorber. Their continuum fluxes make them more likely to be either OII emitters at low redshift, or high redshift AGNs associated with the super-cluster structure reported by Francis and Hewett. \\lya emission sources similar to the ones detected in the field of Q0528-250 are not seen. A comparison of these new results with our previous detections will allow us to draw general conclusions on the nature of the damped systems.

  12. Comparison of sound reproduction using higher order loudspeakers and equivalent line arrays in free-field conditions.

    PubMed

    Poletti, Mark A; Betlehem, Terence; Abhayapala, Thushara D

    2014-07-01

    Higher order sound sources of Nth order can radiate sound with 2N + 1 orthogonal radiation patterns, which can be represented as phase modes or, equivalently, amplitude modes. This paper shows that each phase mode response produces a spiral wave front with a different spiral rate, and therefore a different direction of arrival of sound. Hence, for a given receiver position a higher order source is equivalent to a linear array of 2N + 1 monopole sources. This interpretation suggests performance similar to a circular array of higher order sources can be produced by an array of sources, each of which consists of a line array having monopoles at the apparent source locations of the corresponding phase modes. Simulations of higher order arrays and arrays of equivalent line sources are presented. It is shown that the interior fields produced by the two arrays are essentially the same, but that the exterior fields differ because the higher order sources produces different equivalent source locations for field positions outside the array. This work provides an explanation of the fact that an array of L Nth order sources can reproduce sound fields whose accuracy approaches the performance of (2N + 1)L monopoles.

  13. Childhood cancer and magnetic fields from high-voltage power lines in England and Wales: a case–control study

    PubMed Central

    Kroll, M E; Swanson, J; Vincent, T J; Draper, G J

    2010-01-01

    Background: Epidemiological evidence suggests that chronic low-intensity extremely-low-frequency magnetic-field exposure is associated with increased risk of childhood leukaemia; it is not certain the association is causal. Methods: We report a national case–control study relating childhood cancer risk to the average magnetic field from high-voltage overhead power lines at the child's home address at birth during the year of birth, estimated using National Grid records. From the National Registry of Childhood Tumours, we obtained records of 28 968 children born in England and Wales during 1962–1995 and diagnosed in Britain under age 15. We selected controls from birth registers, matching individually by sex, period of birth, and birth registration district. No participation by cases or controls was required. Results: The estimated relative risk for each 0.2 μT increase in magnetic field was 1.14 (95% confidence interval 0.57 to 2.32) for leukaemia, 0.80 (0.43–1.51) for CNS/brain tumours, and 1.34 (0.84–2.15) for other cancers. Conclusion: Although not statistically significant, the estimate for childhood leukaemia resembles results of comparable studies. Assuming causality, the estimated attributable risk is below one case per year. Magnetic-field exposure during the year of birth is unlikely to be the whole cause of the association with distance from overhead power lines that we previously reported. PMID:20877338

  14. X-ray Spectroscopy of Hot Dense Plasmas: Experimental Limits, Line Shifts and Field Effects

    SciTech Connect

    Renner, Oldrich; Sauvan, Patrick; Dalimier, Elisabeth; Riconda, Caterina; Rosmej, Frank B.; Weber, Stefan; Nicolai, Philippe; Peyrusse, Olivier; Uschmann, Ingo; Hoefer, Sebastian; Kaempfer, Tino; Loetzsch, Robert; Zastrau, Ulf; Foerster, Eckhart; Oks, Eugene

    2008-10-22

    High-resolution x-ray spectroscopy is capable of providing complex information on environmental conditions in hot dense plasmas. Benefiting from application of modern spectroscopic methods, we report experiments aiming at identification of different phenomena occurring in laser-produced plasma. Fine features observed in broadened profiles of the emitted x-ray lines and their satellites are interpreted using theoretical models predicting spectra modification under diverse experimental situations.

  15. Field Test Results of Corrosion-Resistant Coatings for Carbon-Steel Steam Condensate Return Lines

    DTIC Science & Technology

    1994-04-01

    20 and 40 ppm. Note that addition of sodium sulfite promotes a higher level of total dissolved solids, which increases the boiler blowdown rate. 2O...some form of external treatment process, including- 1. Demineralization 2. Hot lime softening 3. Split-stream, sodium hydrogen, ion exchange 4. Chloride...water due to system leakage occuring in carbon-steel condensate return lines within buildings. The makeup water is taken from the Potomac River, sodium

  16. Biogeochemistry of hydrothermally and adjacent non-altered soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a field/lab project, students in the Soil Biogeochemistry class of the University of Nevada, Reno described and characterized seven pedons, developed in hydrothermally and adjacent non-hydrothermally altered andesitic parent material near Reno, NV. Hydrothermally altered soils had considerably lo...

  17. Measurement Methods to Determine Air Leakage Between Adjacent Zones

    SciTech Connect

    Hult, Erin L.; Dickerhoff, Darryl J.; Price, Phillip N.

    2012-09-01

    Air leakage between adjacent zones of a building can lead to indoor air quality and energy efficiency concerns, however there is no existing standard for measuring inter-zonal leakage. In this study, synthesized data and field measurements are analyzed in order to explore the uncertainty associated with different methods for collecting and analyzing fan pressurization measurements to calculate interzone leakage.

  18. Freja observations of electromagnetic ion cyclotron ELF waves and transverse oxygen ion acceleration on auroral field lines

    SciTech Connect

    Erlandson, R.E.; Zanetti, L.J.; Acuna, M.H.; Eliasson, L.; Boehm, M.H.; Blomberg, L.G.

    1994-08-15

    Extremely low-frequency (ELF) magnetic and electric field plasma wave emissions were recorded on 2 October 1993 on auroral field lines by the Magnetic Field Experiment during Freja orbit 4770. The ELF wave frequencies were below the local oxygen gyrofrequency (25 Hz) and between the helium and proton gyrofrequencies (100 to 400 Hz). The ELF waves, interpreted as electromagnetic ion cyclotron (EMIC) waves, were observed in a region of inverted-V-type electron precipitation. The EMIC waves were correlated over time with auroral and lower energy ({approximately} 100 eV) electrons, which are both possible sources of free energy, and also with transversely accelerated oxygen ions. The waves above the helium gyrofrequency were more closely correlated with the transverse oxygen ion acceleration than the waves below the oxygen gyrofrequency. These observations are consistent with a scenario in which electron beams generate EMIC waves, which then produce transverse oxygen ion acceleration through a gyroresonant interaction. 16 refs., 4 figs.

  19. Two-spacecraft charged particle observations interpreted in terms of electrostatic potential drops along polar cap field lines

    NASA Astrophysics Data System (ADS)

    Pollock, C. J.; Chappell, C. R.; Horwitz, J. L.; Winningham, J. D.

    We are studying the possible occurrence and magnitude of field-aligned electrostatic potential drops over the ionospheric polar caps. For this purpose, signatures in upgoing and downgoing photoelectrons, obtained in the topside ionosphere using the low altitude plasma instrument (LAPI) on the Dynamics Explorer 2 (DE 2), spacecraft are analyzed [Winningham and Gurgiolo, 1982]. These data are compared with positive ion data obtained at high altitude using the retarding ion mass spectrometer (RIMS) on the DE 1 spacecraft. Data were selected from intervals when DE 1 and DE 2 were approximately connected along polar cap magnetic field lines and when upflowing 0+ beams were observed in the RIMS data. We present here one case in which the comparison of data from the two DE spacecraft is quite favorable regarding its interpretation in terms of a field-aligned potential drop.

  20. A laboratory study of ion energization by EIC waves and subsequent upstreaming along diverging magnetic field lines

    NASA Technical Reports Server (NTRS)

    Cartier, S. L.; Dangelo, N.; Merlino, R. L.

    1986-01-01

    A laboratory study related to energetic upstreaming ions in the ionosphere-magnetosphere system is described. The experiment was carried out in a cesium Q machine plasma with a region of nonuniform magnetic field. Electrostatic ion cyclotron waves were excited by drawing an electron current to a small biased exciter electrode. In the presence of the instability, ions are heated in the direction perpendicular to B. Using a gridded retarding potential ion energy analyzer, the evolution of the ion velocity distribution was followed as the ions passed through the heating region and subsequently flowed out along the diverging B field lines. As expected, the heated ions transfer their energy from perpendicular to parallel motion as they move through the region of diverging B field. Both their parallel thermal energy and the parallel drift energy increase at the expense of the perpendicular energy.

  1. HIDES spectroscopy of bright detached eclipsing binaries from the Kepler field - I. Single-lined objects

    NASA Astrophysics Data System (ADS)

    Hełminiak, K. G.; Ukita, N.; Kambe, E.; Kozłowski, S. K.; Sybilski, P.; Ratajczak, M.; Maehara, H.; Konacki, M.

    2016-09-01

    We present results of our spectroscopic observations of nine detached eclipsing binaries (DEBs), selected from the Kepler Eclipsing Binary Catalog, that only show one set of spectral lines. Radial velocities (RVs) were calculated from the high-resolution spectra obtained with the HIgh-Dispersion Echelle Spectrograph (HIDES) instrument, attached to the 1.88-m telescope at the Okayama Astrophysical Observatory, and from the public Apache Point Observatory Galactic Evolution Experiment archive. In our sample, we found five single-lined binaries, with one component dominating the spectrum. The orbital and light-curve solutions were found for four of them, and compared with isochrones, in order to estimate absolute physical parameters and evolutionary status of the components. For the fifth case, we only update the orbital parameters, and estimate the properties of the unseen star. Two other systems show orbital motion with a period known from the eclipse timing variations (ETVs). For these we obtained parameters of outer orbits, by translating the ETVs to RVs of the centre of mass of the eclipsing binary, and combining with the RVs of the outer star. Of the two remaining ones, one is most likely a blend of a faint background DEB with a bright foreground star, which lines we see in the spectra, and the last case is possibly a quadruple bearing a sub-stellar mass object. Where possible, we compare our results with literature, especially with results from asteroseismology. We also report possible detections of solar-like oscillations in our RVs.

  2. Why an ac magnetic field shifts the irreversibility line in type-II superconductors.

    PubMed

    Brandt, Ernst Helmut; Mikitik, Grigorii P

    2002-07-08

    We show that for a thin superconducting strip placed in a transverse dc magnetic field--the typical geometry of experiments with high-T(c) superconductors--the application of a weak ac magnetic field perpendicular to the dc field generates a dc voltage in the strip. This voltage leads to the decay of the critical currents circulating in the strip, and eventually the equilibrium state of the superconductor is established. This relaxation is not due to thermally activated flux creep but to the "walking" motion of vortices in the two-dimensional critical state of the strip with in-plane ac field. Our theory explains the shaking effect that was used for detecting phase transitions of the vortex lattice in superconductors.

  3. Environmental Assessment: Construct Wastewater Re-use Line at Hurlburt Field

    DTIC Science & Technology

    2003-09-01

    EM, Eglin AFB, FL • Randy Trent - 16 CES/CEV, Hurlburt Field, FL • Don Williams - 16 CES/CEO, Hurlburt Field, FL 23 I I I I I I I I I I I...8217 Duncan Jay Cairns Chief, Bur. Env. & Res. Ping. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I

  4. Magnetic fields of high voltage power lines and risk of cancer in Finnish adults: nationwide cohort study.

    PubMed Central

    Verkasalo, P. K.; Pukkala, E.; Kaprio, J.; Heikkilä, K. V.; Koskenvuo, M.

    1996-01-01

    OBJECTIVE: To investigate the risk of cancer in association with magnetic fields in Finnish adults living close to high voltage power lines. DESIGN: Nationwide cohort study. SUBJECTS: 383,700 people who lived during 1970-89 within 500 metres of overhead power lines of 110-400 kV in a magnetic field calculated to be > or = 0.01 microT. Study subjects were identified by record linkages of nationwide registers. MAIN OUTCOME MEASURES: Numbers of observed and expected cases of cancer, standardised incidence ratios, and incidence rate ratios adjusted for sex, age, calendar year, and social class--for example, by continuous cumulative exposure per 1 microT year with 95% confidence intervals from multiplicative models for all cancers combined and 21 selected types. RESULTS: Altogether 8415 cases of cancer were observed (standardised incidence ratio 0.98; 95% confidence interval 0.96 to 1.00) in adults. All incidence rate ratios for both sexes combined were non-significant and between 0.91 and 1.11. Significant excesses were observed in multiple myeloma in men (incidence rate ratio 1.22) and in colon cancer in women (1.16). CONCLUSIONS: Typical residential magnetic fields generated by high voltage power lines do not seem to be related to the risk of overall cancer in adults. The previously suggested associations between extremely low frequency magnetic fields and tumours of the nervous system, lymphoma, and leukaemia in adults and breast cancer in women were not confirmed. PMID:8898595

  5. The Spreading of X-lines in Three Dimensions during Magnetic Reconnection with a Guide Field

    NASA Astrophysics Data System (ADS)

    Shepherd, L. S.; Cassak, P.

    2011-12-01

    Naturally occurring magnetic reconnection often begins in a spatially localized region and spreads in the out-of-plane direction as time progresses. This has been studied by a number of authors for magnetotail applications such as substorms and bursty bulk flows, for which the out-of-plane (guide) field is typically small. However, this same behavior has been observed in laboratory experiments, in two-ribbon solar flares (such as the Bastille Day flare), and at the dayside of the magnetopause. In each of these settings, a significant guide field is present. Without a guide field, it was shown that the reconnection spreading is controlled by the species that carries the current. However, laboratory experiments with a large guide field (Katz et al., Phys. Rev. Lett., 104, 255004, 2010) revealed that the spreading takes place in both directions at the Alfven speed based on the guide magnetic field. We present three-dimensional two-fluid numerical simulations to address the condition on the guide field at which the nature of the spreading switches from being caused by the current carriers to being caused by Alfven waves. Applications for the corona will be discussed.

  6. Spectropolarimetry in the Sodium 589.6nm D1 line: Evaluating the Resulting Chromospheric (?) Vector Field Maps.

    NASA Astrophysics Data System (ADS)

    Leka, K. D.

    2012-05-01

    Pioneering work by T. R. Metcalf almost two decades ago pointed to the Na 589.6nm D1 line as a contender for providing chromospheric vector magnetic field measurements (using the Zeeman effect). We report here on a systematic examination of what can be expected from Sodium 589.6nm spectropolarimetry, with respects to polarization-signal amplitudes and retrieval, and the implementation of the inversion for this line based on the Jeffries, Lites & Skumanich Weak-Field Approximation algorithm. The analysis is performed using both synthetic data and observations from the Imaging Vector Magnetograph, for which a large dataset of Sodium 589.6nm vector spectropolarimetry exists. The synthetic data are based on a 3-D field extrapolated from photospheric vector magnetograms of two active regions, four distinct model atmospheres coupled with NLTE synthesis of the emergent NaI D1 Stokes polarization spectra, computed for a variety of viewing angles. In this manner, a broad representation of active-region features, field strengths and observing angles are tested using ``hare & hound'' approaches, including evaluating algorithm performance in the presence of noise and instrumental effects. We compare retrieval algorithms for the very weak (as expected) polarization signals, and evaluate the retrieved vector magnetic field at a range of inferred heights. Finally, we provide an example from the IVM and discuss the prospects for obtaining and interpreting chromospheric vector magnetic field maps. Support for this work comes from NASA NAG5-12466, NASA NNH09CE60C, AFOSR F49620-03-C-0019, NSF/NSWP ATM-0519107, NSF/SHINE ATM-0454610, and NSF CRG ATM-0551055.

  7. The Effect of Dissipation Mechanism and Guide Field Strength on X-line Spreading in 3D Magnetic Reconnection

    NASA Astrophysics Data System (ADS)

    Shepherd, Lucas; Cassak, P.; Drake, J.; Gosling, J.; Phan, T.; Shay, M. A.

    2013-07-01

    In two-ribbon flares, the fact that the ribbons separate in time is considered evidence of magnetic reconnection. However, in addition to the ribbons separating, they can also elongate (as seen in animations of, for example, the Bastille Day flare). The elongation is undoubtedly related to the reconnection spreading in the out-of-plane direction. Indeed, naturally occurring magnetic reconnection generally begins in a spatially localized region and spreads in the direction perpendicular to the reconnection plane as time progresses. For example, it was suggested that X-line spreading is necessary to explain the observation of X-lines extending more than 390 Earth radii (Phan et al., Nature, 404, 848, 2006), and has been seen in reconnection experiments. A sizeable out-of-plane (guide) magnetic field is present at flare sites and in the solar wind. Here, we study the effect of dissipation mechanism and the strength of the guide field has on X-line spreading. We present results from three-dimensional numerical simulations of magnetic reconnection, comparing spreading with the Hall term to spreading with anomalous resistivity. Applications to solar flares and magnetic reconnection in the solar wind will be discussed.

  8. Electric Mars: A large trans-terminator electric potential drop on closed magnetic field lines above Utopia Planitia

    NASA Astrophysics Data System (ADS)

    Collinson, Glyn; Mitchell, David; Xu, Shaosui; Glocer, Alex; Grebowsky, Joseph; Hara, Takuya; Lillis, Robert; Espley, Jared; Mazelle, Christian; Sauvaud, Jean-André; Fedorov, Andrey; Liemohn, Mike; Andersson, Laila; Jakosky, Bruce

    2017-02-01

    Parallel electric fields and their associated electric potential structures play a crucial role in ionospheric-magnetospheric interactions at any planet. Although there is abundant evidence that parallel electric fields play key roles in Martian ionospheric outflow and auroral electron acceleration, the fields themselves are challenging to directly measure due to their relatively weak nature. Using measurements by the Solar Wind Electron Analyzer instrument aboard the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) Mars Scout, we present the discovery and measurement of a substantial (ΦMars=7.7 ± 0.6 V) parallel electric potential drop on closed magnetic field lines spanning the terminator from day to night above the great impact basin of Utopia Planitia, a region largely free of crustal magnetic fields. A survey of the previous 26 orbits passing over a range of longitudes revealed similar signatures on seven orbits, with a mean potential drop (ΦMars) of 10.9 ± 0.8 V, suggestive that although trans-terminator electric fields of comparable strength are not ubiquitous, they may be common, at least at these northerly latitudes.

  9. Pc 3-4 Pulsations Near the Cusp: Latitude dependence near the open-closed field line boundary

    NASA Astrophysics Data System (ADS)

    Yeoman, T. K.; Wright, D. M.; Clausen, L. B.; Engebretson, M.; Lu, F.; Posch, J.; Lessard, M.; Kim, H.

    2008-12-01

    Dayside ground magnetometer records at high latitudes frequently show evidence of Pc 3-4 pulsations (f ~ 10-100 mHz) which originate in the ion foreshock upstream of the Earth's bow shock due to the interaction between reflected ions and the solar wind. Previous studies have noted increased Pc 3-4 wave power in the vicinity of the dayside cusp and inferred that the upstream waves gained entry via the cusp, although more recent studies have revealed a more complex picture. Here, we examine Pc3-4 wave power near local noon observed by search coil magnetometers at three closely-spaced stations on Svalbard. Three intervals are chosen when the upstream conditions are favourable for Pc3-4 generation, clear band-limited Pc3-4 wave power is observed near local noon, and an extended interval of HF radar backscatter indicative of the cusp is detected by the Hankasalmi SuperDARN radar. A stereo mode of radar operation is employed, such that 3 s time resolution is available on one radar beam, whilst the high latitude convection is revealed with 1 min. resolution. The location of the equatorward edge of the HF radar cusp may then be directly compared with the Pc3-4 wave power measured at three latitudes as the cusp migrates across the stations. The radar data show clear evidence of transient ionospheric flows and high spectral widths associated with field lines newly- opened by dayside reconnection processes, but no evidence of oscillations in the Pc3-4 frequency range. In the ground magnetic field a peak in Pc3-4 power is generally observed in the equatormost magnetometer, except when the cusp is significantly poleward of the stations, consistent with a peak in wave power ~4 degrees equatorward of the cusp, but suggesting a modest dependence of wave power with latitude on closed field lines When the cusp does move equatorward of the magnetometer stations the Pc3-4 power drops rapidly, and does so earliest at the most poleward magnetometer station, suggesting a sharp drop in

  10. Estimation of local planetary gravity fields using line of sight gravity data and an integral operator

    NASA Technical Reports Server (NTRS)

    Barriot, J. P.; Balmino, G.

    1992-01-01

    A novel method is presented for mapping line-of-sight gravity data (LOSGD) joining planetary probes and observers during Doppler tracking operations, with a view to geodetic and geophysical applications. LOSGD are in this case mapped as gravity anomalies along a radial direction, at constant altitude, using an inversion procedure in conjunction with a Tikhonov-Arsenine regularization method. The application of different regularization-parameter choices to a synthetic case is followed by application to the real case of Pioneer-Venus orbiter data for Venus' Gula Mons.

  11. Linear polarization of resonance lines in the absence of magnetic fields. II - Semi-infinite atmospheres

    NASA Astrophysics Data System (ADS)

    Faurobert, M.

    1988-04-01

    Polarization profiles of resonance lines formed in magnetic free semiinfinite atmospheres having either a uniform temperature or a chromospheric-type temperature rise are considered. In the isothermal case, a comparison is made between profiles calculated with the angle- and frequency-dependent R(II) partial redistribution and those given by the angle-averaged form of R(II), which is a simplified version of it introduced by Ayres (1985) and the Kneer (1975) approximation. It is found that, in chromospheric models, a maximum of polarization perpendicular to the surface appears at frequencies which are formed in the region of the temperature rise.

  12. Estimation of local planetary gravity fields using line of sight gravity data and an integral operator

    NASA Astrophysics Data System (ADS)

    Barriot, J. P.; Balmino, G.

    1992-09-01

    A novel method is presented for mapping line-of-sight gravity data (LOSGD) joining planetary probes and observers during Doppler tracking operations, with a view to geodetic and geophysical applications. LOSGD are in this case mapped as gravity anomalies along a radial direction, at constant altitude, using an inversion procedure in conjunction with a Tikhonov-Arsenine regularization method. The application of different regularization-parameter choices to a synthetic case is followed by application to the real case of Pioneer-Venus orbiter data for Venus' Gula Mons.

  13. Aerodynamic Mixing Downstream from Line Source of Heat in High-intensity Sound Field

    NASA Technical Reports Server (NTRS)

    Mickelson, William R; Baldwin, Lionel V

    1956-01-01

    Theory and measurement showed that the heat wake downstream from a line source is displaced by a transverse standing sound wave in a manner similar to a flag waving in a harmonic mode. With a 147 db, 104 cps standing wave, time-mean temperatures were reduced by an order of magnitude except near the displacement-pattern nodal points. The theory showed that a 161 db, 520 cps standing wave considerably increased the mixing in both the time-mean and instantaneous senses.

  14. A Physics-based Automated Technique for the Detection of Field Line Resonance Frequency in Ground Magnetometer Data

    NASA Astrophysics Data System (ADS)

    Boudouridis, A.; Zesta, E.; Moldwin, M.

    2015-12-01

    The accurate determination of the Field Line Resonance (FLR) frequency of a resonating geomagnetic field line is necessary for the remote monitoring of the plasmaspheric mass density during geomagnetic storms and quiet times alike. Under certain assumptions the plasmaspheric mass density at the equator is inversely proportional to the square of the FLR frequency. The most common techniques to determine the FLR frequency from ground magnetometer measurements are the amplitude ratio and phase difference techniques, both based on geomagnetic field measurements at two latitudinally separated ground stations. Previously developed automated techniques have used statistical methods to pinpoint the FLR frequency using the amplitude ratio and phase difference calculations. We now introduce a physics-based automated technique that can reproduce the resonant wave characteristics from the two ground station data, and from those determine the FLR frequency. The advantage of the new technique, besides moving away from ambiguous statistical manipulations of the ground data, is the estimation of physically determined errors of the FLR frequency, which can yield physically determined errors of the equatorial plasmaspheric mass density. We present preliminary results of the new technique calculations, and test it using data from the new Inner-Magnetospheric Array for Geospace Science (iMAGS) ground magnetometer chain along the coast of Chile and the east coast of the United States. We compare the results with the results of previously published statistical automated techniques.

  15. VLF Radio Field Strength Measurement of power line carrier system in San Diego, California

    NASA Technical Reports Server (NTRS)

    Mertel, H. K.

    1981-01-01

    The radio frequency interference (RFI) potential was evaluated for a Powerline Carriet (PLC) installed in San Diego which monitors the performance of an electrical power system. The PLC system generated 30 amperes at 5.79 kHz. The RF radiations were measured to be (typically) 120 dBuV/m at the beginning of the 12 kV powerline and 60 dBuV/m at the end of the powerline. The RF fields varied inversely as the distance squared. Measurements were also performed with a 45 kHz PLC system. The RF fields were of similar amplitude.

  16. In vitro cytotoxicity of Selol-loaded magnetic nanocapsules against neoplastic cell lines under AC magnetic field activation

    NASA Astrophysics Data System (ADS)

    Falqueiro, A. M.; Siqueira-Moura, M. P.; Jardim, D. R.; Primo, F. L.; Morais, P. C.; Mosiniewicz-Szablewska, E.; Suchocki, P.; Tedesco, A. C.

    2012-04-01

    The goals of this study are to evaluate invitro compatibility of magnetic nanomaterials and their therapeutic potential against cancer cells. Highly stable ionic magnetic fluid sample (maghemite, γ-Fe2O3) and Selol were incorporated into polymeric nanocapsules by nanoprecipitation method. The cytotoxic effect of Selol-loaded magnetic nanocapsules was assessed on murine melanoma (B16-F10) and oral squamous cell carcinoma (OSCC) cell lines following AC magnetic field application. The influence of different nanocapsules on cell viability was investigated by colorimetric MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. In the absence of AC magnetic field Selol-loaded magnetic nanocapsules, containing 100 µg/mL Selol plus 5 × 1012 particle/mL, showed antitumoral activity of about 50% on B16-F10 melanoma cells while OSCC carcinoma cells demonstrated drug resistance at all concentrations of Selol and magnetic fluid (range of 100-500 µg/mL Selol and 5 × 1012-2.5 × 1013 particle/mL). On the other hand, under AC applied fields (1 MHz and 40 Oe amplitude) B16-F10 cell viability was reduced down to 40.5% (±3.33) at the highest concentration of nanoencapsulated Selol. The major effect, however, was observed on OSCC cells since the cell viability drops down to about 33.3% (±0.38) under application of AC magnetic field. These findings clearly indicate that the Selol-loaded magnetic nanocapsules present different toxic effects on neoplastic cell lines. Further, the cytotoxic effect was maximized under AC magnetic field application on OSCC, which emphasizes the effectiveness of the magnetohyperthermia approach.

  17. High intensity proton beam transportation through fringe field of 70 MeV compact cyclotron to beam line targets

    NASA Astrophysics Data System (ADS)

    Zhang, Xu; Li, Ming; Wei, Sumin; Xing, Jiansheng; Hu, Yueming; Johnson, Richard R.; Piazza, Leandro; Ryjkov, Vladimir

    2016-06-01

    From the stripping points, the high intensity proton beam of a compact cyclotron travels through the fringe field area of the machine to the combination magnet. Starting from there the beams with various energy is transferred to the switching magnet for distribution to the beam line targets. In the design of the extraction and transport system for the compact proton cyclotron facilities, such as the 70 MeV in France and the 100 MeV in China, the space charge effect as the beam crosses the fringe field has not been previously considered; neither has the impact on transverse beam envelope coupled from the longitudinal direction. Those have been concerned much more with the higher beam-power because of the beam loss problem. In this paper, based on the mapping data of 70 MeV cyclotron including the fringe field by BEST Cyclotron Inc (BEST) and combination magnet field by China Institute of Atomic Energy (CIAE), the beam extraction and transport are investigated for the 70 MeV cyclotron used on the SPES project at Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (INFN-LNL). The study includes the space charge effect and longitudinal and transverse coupling mentioned above, as well as the matching of beam optics using the beam line for medical isotope production as an example. In addition, the designs of the ±45° switching magnets and the 60° bending magnet for the extracted beam with the energy from 35 MeV to 70 MeV have been made. Parts of the construction and field measurements of those magnets have been done as well. The current result shows that, the design considers the complexity of the compact cyclotron extraction area and fits the requirements of the extraction and transport for high intensity proton beam, especially at mA intensity levels.

  18. Field Trial of LANL On-Line Advanced Enrichment Monitor for UF6 GCEP

    SciTech Connect

    Ianakiev, Kiril D.; Lombardi, Marcie; MacArthur, Duncan W.; Parker, Robert F.; Smith, Morag K.; Keller, Clifford; Friend, Peter; Dunford, Andrew

    2012-07-13

    The outline of this presentation is: (1) Technology basis of on-line enrichment monitoring; (2) Timescale of trial; (3) Description of installed equipment; (4) Photographs; (5) Results; (6) Possible further development; and (7) Conclusions. Summary of the good things about the Advanced Enrichment Monitor (AEM) performance is: (1) High accuracy - normally better than 1% relative, (2) Active system as accurate as passive system, (3) Fast and accurate detection of enrichment changes, (4) Physics is well understood, (5) Elegant method for capturing pressure signal, and (6) Data capture is automatic, low cost and fast. A couple of negative things are: (1) Some jumps in measured passive enrichment - of around +2% relative (due to clock errors?); and (2) Data handling and evaluation is off-line, expensive and very slow. Conclusions are: (1) LANL AEM is being tested on E23 plant at Capenhurst; (2) The trial is going very well; (3) AEM could detect production of HEU at potentially much lower cost than existing CEMO; (4) AEM can measure {sup 235}U assay accurately; (5) Active system using X-Ray source would avoid need for pressure measurement; (6) Substantial work lies ahead to go from current prototype to a production instrument.

  19. On-line field measurements of VOC emissions from a spruce tree at SMEAR Estonia

    NASA Astrophysics Data System (ADS)

    Bourtsoukidis, Efstratios; Bonn, Boris; Noe, Steffen

    2013-04-01

    We have investigated VOC emissions from a Norway spruce tree (Picea abies) in a hemi-boreal mixed forest in September and October 2012, using Proton Transfer Reaction Mass Spectrometry and Gas Chromatography - Mass Spectrometry techniques, applied in a dynamic branch enclosure system that was automatically operated with an electrical compressor. Parallel to BVOC measurements a vast amount of atmospheric (CO2, CH4, H2O, CO, particles) and meteorological (temperature, relative humidity, photosynthetic active radiation, wind speed and direction, precipitation) parameters were measured in the ambient atmosphere and inside the cuvette enclosure (temperature, relative humidity, O3). Prior to the measuring period, an innovatory experimental setup was built at Järvselja forest station, in order to accomplish the detection of BVOC and minimize sampling losses. Therefore, a new inlet line, consisting of 19.4m of heated and isolated glass tube was constructed. The new inlet system applied, allowed the on-line detection and calculation of sesquiterpene (SQT) emission rates for the first time in a hemi-boreal forest site. It total, 12 atmospheric relevant BVOCs were continuously monitored for a three week period and the emission rates were derived. Along with diurnal profiles and continuous timeless, some interesting observations showed the possibility of ozone effect on SQT emissions, the possibility of radiation effect on MT emissions, the higher induced emissions due to mechanical stress and the possibility for a valid intercomparison between different spruce trees located in mountain Kleiner Feldberg (Germany) and in Järvseja forest station (Estonia).

  20. Investigation of superparamagnetic (Fe3O4) nanoparticles and magnetic field exposures on CHO-K1 cell line

    NASA Astrophysics Data System (ADS)

    Coker, Zachary; Estlack, Larry; Hussain, Saber; Choi, Tae-Youl; Ibey, Bennett L.

    2016-03-01

    Rapid development in nanomaterial synthesis and functionalization has led to advanced studies in actuation and manipulation of cellular functions for biomedical applications. Often these actuation techniques employ externally applied magnetic fields to manipulate magnetic nanomaterials inside cell bodies in order to drive or trigger desired effects. While cellular interactions with low-frequency magnetic fields and nanoparticles have been extensively studied, the fundamental mechanisms behind these interactions remain poorly understood. Additionally, modern investigations on these concurrent exposure conditions have been limited in scope, and difficult to reproduce. This study presents an easily reproducible method of investigating the biological impact of concurrent magnetic field and nanoparticle exposure conditions using an in-vitro CHO-K1 cell line model, with the purpose of establishing grounds for in-depth fundamental studies of the mechanisms driving cellular-level interactions. Cells were cultured under various nanoparticle and magnetic field exposure conditions from 0 to 500 μg/ml nanoparticle concentrations, and DC, 50 Hz, or 100 Hz magnetic fields with 2.0 mT flux density. Cells were then observed by confocal fluorescence microscopy, and subject to biological assays to determine the effects of concurrent extreme-low frequency magnetic field and nanoparticle exposures on cellnanoparticle interactions, such as particle uptake and cell viability by MTT assay. Current results indicate little to no variation in effect on cell cultures based on magnetic field parameters alone; however, it is clear that deleterious synergistic effects of concurrent exposure conditions exist based on a significant decrease in cell viability when exposed to high concentrations of nanoparticles and concurrent magnetic field.

  1. Field evaluation of soybean lines from a new source of resistance to Cercospora kikuchii, 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purple seed stain, which is caused by the fungus Cercospora kikuchii, is an important seed disease which causes soybean seed quality losses when environmental conditions favor its growth, and harvest is delayed due to wet field conditions. Frogeye leaf spot caused by the fungus Cercospora sojina is...

  2. Biological effects from electric fields associated with high voltage transmission lines

    SciTech Connect

    Not Available

    1983-11-01

    Efforts during the past year by the US Department of Energy and the Electric Power Research Institute-funded laboratories to investigate the biological effects from electric fields are described in resume form. Investigations generally have been summarized with objectives, accomplishments of the past year, and some indication of projected studies.

  3. Effects of sinusoidal magnetic field observed on cell proliferation, ion concentration, and osmolarity in two human cancer cell lines.

    PubMed

    Huang, Lingzhen; Dong, Liang; Chen, Yantian; Qi, Hanshi; Xiao, Dengming

    2006-01-01

    Low frequency magnetic fields have previously been shown to affect cell functions. In this article, the effects of 20 mT, 50 Hz sinusoidal magnetic field on cell proliferation, ion concentration, and osmolarity in two human cancer cell lines (HL-60 and SK-Hep-1) were investigated. Inhibition of cell growth was observed. On the other hand, the exposure also increased the Na+, K+ ion concentration and osmolarity in cell supernatant compared to the control group. To our knowledge, this is the first study on cancer cells where magnetic fields affect osmolarity in cell supernatant. In addition, a model of cells exposed to the oscillating magnetic field is described as well as the characteristics of ions in and out of cells. The experimental data appears to be consistent with the theoretical analysis. The results are also discussed in terms of the relationships among cell growth, ion concentration, and osmolarity. Magnetic field inhibitions of cell growth in vitro may relate to changes in cell ion concentration and osmolarity.

  4. High-harmonic fast-wave power flow along magnetic field lines in the scrape-off layer of NSTX.

    PubMed

    Perkins, R J; Hosea, J C; Kramer, G J; Ahn, J-W; Bell, R E; Diallo, A; Gerhardt, S; Gray, T K; Green, D L; Jaeger, E F; Jaworski, M A; LeBlanc, B P; McLean, A; Maingi, R; Phillips, C K; Roquemore, L; Ryan, P M; Sabbagh, S; Taylor, G; Wilson, J R

    2012-07-27

    A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive.

  5. The dayside open/closed field line boundary as seen from space- and ground-based instrumentation

    NASA Astrophysics Data System (ADS)

    Johnsen, M. G.; Lorentzen, D. A.

    2012-03-01

    In this paper we validate the method of Johnsen et al. (2012) for obtaining the cusp open/closed field line boundary (OCB) by the means of a single meridian scanning photometer (MSP). Three cases of conjugate measurements between the Longyearbyen MSP and the NOAA-16 satellite are presented. The satellite OCB as obtained by the energetic particle detectors carried onboard the NOAA-16 satellite is well co-located with the OCB as obtained by the ground-based MSP and well within the calculated uncertainties. We conclude that the method presented by Johnsen et al. (2012) for deriving the cusp OCB using a single MSP produces conscientious results.

  6. The GEANT4 toolkit capability in the hadron therapy field: simulation of a transport beam line

    NASA Astrophysics Data System (ADS)

    Cirrone, G. A. P.; Cuttone, G.; Di Rosa, F.; Raffaele, L.; Russo, G.; Guatelli, S.; Pia, M. G.

    2006-01-01

    At Laboratori Nazionali del Sud of the Instituto Nazionale di Fisica Nucleare of Catania (Sicily, Italy), the first Italian hadron therapy facility named CATANA (Centro di AdroTerapia ed Applicazioni Nucleari Avanzate) has been realized. Inside CATANA 62 MeV proton beams, accelerated by a superconducting cyclotron, are used for the radiotherapeutic treatments of some types of ocular tumours. Therapy with hadron beams still represents a pioneer technique, and only a few centers worldwide can provide this advanced specialized cancer treatment. On the basis of the experience so far gained, and considering the future hadron-therapy facilities to be developed (Rinecker, Munich Germany, Heidelberg/GSI, Darmstadt, Germany, PSI Villigen, Switzerland, CNAO, Pavia, Italy, Centro di Adroterapia, Catania, Italy) we decided to develop a Monte Carlo application based on the GEANT4 toolkit, for the design, the realization and the optimization of a proton-therapy beam line. Another feature of our project is to provide a general tool able to study the interactions of hadrons with the human tissue and to test the analytical-based treatment planning systems actually used in the routine practice. All the typical elements of a hadron-therapy line, such as diffusers, range shifters, collimators and detectors were modelled. In particular, we simulated the Markus type ionization chamber and a Gaf Chromic film as dosimeters to reconstruct the depth (Bragg peak and Spread Out Bragg Peak) and lateral dose distributions, respectively. We validated our simulated detectors comparing the results with the experimental data available in our facility.

  7. WIDE-FIELD SURVEY OF EMISSION-LINE STARS IN IC 1396

    SciTech Connect

    Nakano, M.; Sugitani, K.; Watanabe, M.; Fukuda, N.; Ishihara, D.; Ueno, M.

    2012-03-15

    We have made an extensive survey of emission-line stars in the IC 1396 H II region to investigate the low-mass population of pre-main-sequence (PMS) stars. A total of 639 H{alpha} emission-line stars were detected in an area of 4.2 deg{sup 2} and their i' photometry was measured. Their spatial distribution exhibits several aggregates near the elephant trunk globule (Rim A) and bright-rimmed clouds at the edge of the H II region (Rim B and SFO 37, 38, 39, 41), and near HD 206267, which is the main exciting star of the H II region. Based on the extinction estimated from the near-infrared color-color diagram, we have selected PMS star candidates associated with IC 1396. The age and mass were derived from the extinction-corrected color-magnitude diagram and theoretical PMS tracks. Most of our PMS candidates have ages of <3 Myr and masses of 0.2-0.6 M{sub Sun }. Although it appears that only a few stars were formed in the last 1 Myr in the east region of the exciting star, the age difference among subregions in our surveyed area is not clear from the statistical test. Our results may suggest that massive stars were born after the continuous formation of low-mass stars for 10 Myr. The birth of the exciting star could be the late stage of slow but contiguous star formation in the natal molecular cloud. It may have triggered the formation of many low-mass stars at the dense inhomogeneity in and around the H II region by a radiation-driven implosion.

  8. Wide-field Survey of Emission-line Stars in IC 1396

    NASA Astrophysics Data System (ADS)

    Nakano, M.; Sugitani, K.; Watanabe, M.; Fukuda, N.; Ishihara, D.; Ueno, M.

    2012-03-01

    We have made an extensive survey of emission-line stars in the IC 1396 H II region to investigate the low-mass population of pre-main-sequence (PMS) stars. A total of 639 Hα emission-line stars were detected in an area of 4.2 deg2 and their i' photometry was measured. Their spatial distribution exhibits several aggregates near the elephant trunk globule (Rim A) and bright-rimmed clouds at the edge of the H II region (Rim B and SFO 37, 38, 39, 41), and near HD 206267, which is the main exciting star of the H II region. Based on the extinction estimated from the near-infrared color-color diagram, we have selected PMS star candidates associated with IC 1396. The age and mass were derived from the extinction-corrected color-magnitude diagram and theoretical PMS tracks. Most of our PMS candidates have ages of <3 Myr and masses of 0.2-0.6 M ⊙. Although it appears that only a few stars were formed in the last 1 Myr in the east region of the exciting star, the age difference among subregions in our surveyed area is not clear from the statistical test. Our results may suggest that massive stars were born after the continuous formation of low-mass stars for 10 Myr. The birth of the exciting star could be the late stage of slow but contiguous star formation in the natal molecular cloud. It may have triggered the formation of many low-mass stars at the dense inhomogeneity in and around the H II region by a radiation-driven implosion.

  9. Field Research Facility Data Integration Framework Data Management Plan: Survey Lines Dataset

    DTIC Science & Technology

    2016-08-01

    for 5 GB of data storage and 5 GB for the OS and utilities. A minimum of 4 GB memory (RAM) is required. A multiple core Intel or AMD processor ...ER D C/ CH L SR -1 6- 4 Coastal Ocean Data Systems Program Field Research Facility Data Integration Framework Data Management Plan...for other technical reports published by ERDC, visit the ERDC online library at http://acwc.sdp.sirsi.net/client/default. Coastal Ocean Data

  10. Picosecond wide-field time-correlated single photon counting fluorescence microscopy with a delay line anode detector

    NASA Astrophysics Data System (ADS)

    Hirvonen, Liisa M.; Becker, Wolfgang; Milnes, James; Conneely, Thomas; Smietana, Stefan; Le Marois, Alix; Jagutzki, Ottmar; Suhling, Klaus

    2016-08-01

    We perform wide-field time-correlated single photon counting-based fluorescence lifetime imaging (FLIM) with a crossed delay line anode image intensifier, where the pulse propagation time yields the photon position. This microchannel plate-based detector was read out with conventional fast timing electronics and mounted on a fluorescence microscope with total internal reflection (TIR) illumination. The picosecond time resolution of this detection system combines low illumination intensity of microwatts with wide-field data collection. This is ideal for fluorescence lifetime imaging of cell membranes using TIR. We show that fluorescence lifetime images of living HeLa cells stained with membrane dye di-4-ANEPPDHQ exhibit a reduced lifetime near the coverslip in TIR compared to epifluorescence FLIM.

  11. Ion gyroradius effects on particle trapping in kinetic Alfvén waves along auroral field lines

    NASA Astrophysics Data System (ADS)

    Damiano, P. A.; Johnson, J. R.; Chaston, C. C.

    2016-11-01

    In this study, a 2-D self-consistent hybrid gyrofluid-kinetic electron model is used to investigate Alfvén wave propagation along dipolar magnetic field lines for a range of ion to electron temperature ratios. The focus of the investigation is on understanding the role of these effects on electron trapping in kinetic Alfvén waves sourced in the plasma sheet and the role of this trapping in contributing to the overall electron energization at the ionosphere. This work also builds on our previous effort by considering a similar system in the limit of fixed initial parallel current, rather than fixed initial perpendicular electric field. It is found that the effects of particle trapping are strongest in the cold ion limit and the kinetic Alfvén wave is able to carry trapped electrons a large distance along the field line yielding a relatively large net energization of the trapped electron population as the phase speed of the wave is increased. However, as the ion temperature is increased, the ability of the kinetic Alfvén wave to carry and energize trapped electrons is reduced by more significant wave energy dispersion perpendicular to the ambient magnetic field which reduces the amplitude of the wave. This reduction of wave amplitude in turn reduces both the parallel current and the extent of the high-energy tails evident in the energized electron populations at the ionospheric boundary (which may serve to explain the limited extent of the broadband electron energization seen in observations). Even in the cold ion limit, trapping effects in kinetic Alfvén waves lead to only modest electron energization for the parameters considered (on the order of tens of eV) and the primary energization of electrons to keV levels coincides with the arrival of the wave at the ionospheric boundary.

  12. A wide-field TCSPC FLIM system based on an MCP PMT with a delay-line anode.

    PubMed

    Becker, Wolfgang; Hirvonen, Liisa M; Milnes, James; Conneely, Thomas; Jagutzki, Ottmar; Netz, Holger; Smietana, Stefan; Suhling, Klaus

    2016-09-01

    We report on the implementation of a wide-field time-correlated single photon counting (TCSPC) method for fluorescence lifetime imaging (FLIM). It is based on a 40 mm diameter crossed delay line anode detector, where the readout is performed by three standard TCSPC boards. Excitation is performed by a picosecond diode laser with 50 MHz repetition rate. The photon arrival timing is obtained directly from the microchannel plates, with an instrumental response of ∼190 to 230 ps full width at half maximum depending on the position on the photocathode. The position of the photon event is obtained from the pulse propagation time along the two delay lines, one in x and one in y. One end of a delay line is fed into the "start" input of the corresponding TCSPC board, and the other end is delayed by 40 ns and fed into the "stop" input. The time between start and stop is directly converted into position, with a resolution of 200-250 μm. The data acquisition software builds up the distribution of the photons over their spatial coordinates, x and y, and their times after the excitation pulses, typically into 512 × 512 pixels and 1024 time channels per pixel. We apply the system to fluorescence lifetime imaging of cells labelled with Alexa 488 phalloidin in an epi-fluorescence microscope and discuss the application of our approach to other fluorescence microscopy methods.

  13. A wide-field TCSPC FLIM system based on an MCP PMT with a delay-line anode

    NASA Astrophysics Data System (ADS)

    Becker, Wolfgang; Hirvonen, Liisa M.; Milnes, James; Conneely, Thomas; Jagutzki, Ottmar; Netz, Holger; Smietana, Stefan; Suhling, Klaus

    2016-09-01

    We report on the implementation of a wide-field time-correlated single photon counting (TCSPC) method for fluorescence lifetime imaging (FLIM). It is based on a 40 mm diameter crossed delay line anode detector, where the readout is performed by three standard TCSPC boards. Excitation is performed by a picosecond diode laser with 50 MHz repetition rate. The photon arrival timing is obtained directly from the microchannel plates, with an instrumental response of ˜190 to 230 ps full width at half maximum depending on the position on the photocathode. The position of the photon event is obtained from the pulse propagation time along the two delay lines, one in x and one in y. One end of a delay line is fed into the "start" input of the corresponding TCSPC board, and the other end is delayed by 40 ns and fed into the "stop" input. The time between start and stop is directly converted into position, with a resolution of 200-250 μm. The data acquisition software builds up the distribution of the photons over their spatial coordinates, x and y, and their times after the excitation pulses, typically into 512 × 512 pixels and 1024 time channels per pixel. We apply the system to fluorescence lifetime imaging of cells labelled with Alexa 488 phalloidin in an epi-fluorescence microscope and discuss the application of our approach to other fluorescence microscopy methods.

  14. Ising spin glass under continuous-distribution random magnetic fields: Tricritical points and instability lines.

    PubMed

    Crokidakis, Nuno; Nobre, Fernando D

    2008-04-01

    The effects of random magnetic fields are considered in an Ising spin-glass model defined in the limit of infinite-range interactions. The probability distribution for the random magnetic fields is a double Gaussian, which consists of two Gaussian distributions centered, respectively, at +H0 and -H0, presenting the same width sigma . It is argued that such a distribution is more appropriate for a theoretical description of real systems than its simpler particular two well-known limits, namely, the single Gaussian distribution (sigma>H0) and the bimodal one (sigma=0) . The model is investigated by means of the replica method, and phase diagrams are obtained within the replica-symmetric solution. Critical frontiers exhibiting tricritical points occur for different values of sigma , with the possibility of two tricritical points along the same critical frontier. To our knowledge, it is the first time that such a behavior is verified for a spin-glass model in the presence of a continuous-distribution random field, which represents a typical situation of a real system. The stability of the replica-symmetric solution is analyzed, and the usual Almeida-Thouless instability is verified for low temperatures. It is verified that the higher-temperature tricritical point always appears in the region of stability of the replica-symmetric solution; a condition involving the parameters H0 and sigma , for the occurrence of this tricritical point only, is obtained analytically. Some of our results are discussed in view of experimental measurements available in the literature.

  15. Acoustic emission and magnification of atomic lines resolution for laser breakdown of salt water in ultrasound field

    SciTech Connect

    Bulanov, Alexey V.; Nagorny, Ivan G.

    2015-10-28

    Researches of the acoustic effects accompanying optical breakdown in a water, generated by the focused laser radiation with power ultrasound have been carried out. Experiments were performed by using 532 nm pulses from Brilliant B Nd:YAG laser. Acoustic radiation was produced by acoustic focusing systems in the form hemisphere and ring by various resonance frequencies of 10.7 kHz and 60 kHz. The experimental results are obtained, that show the sharply strengthens effects of acoustic emission from a breakdown zone by the joint influence of a laser and ultrasonic irradiation. Essentially various thresholds of breakdown and character of acoustic emission in fresh and sea water are found out. The experimental result is established, testifying that acoustic emission of optical breakdown of sea water at presence and at absence of ultrasound essentially exceeds acoustic emission in fresh water. Atomic lines of some chemical elements like a Sodium, Magnesium and so on were investigated for laser breakdown of water with ultrasound field. The effect of magnification of this lines resolution for salt water in ultrasound field was obtained.

  16. Generalized potentials for a mean-field density functional theory of a three-phase contact line

    NASA Astrophysics Data System (ADS)

    Lin, Chang-You; Widom, Michael; Sekerka, Robert F.

    2013-07-01

    We investigate generalized potentials for a mean-field density functional theory of a three-phase contact line. Compared to the symmetrical potential introduced in our previous article [Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.85.011120 85, 011120 (2012)], the three minima of these potentials form a small triangle located arbitrarily within the Gibbs triangle, which is more realistic for ternary fluid systems. We multiply linear functions that vanish at edges and vertices of the small triangle, yielding potentials in the form of quartic polynomials. We find that a subset of such potentials has simple analytic far-field solutions and is a linear transformation of our original potential. By scaling, we can relate their solutions to those of our original potential. For special cases, the lengths of the sides of the small triangle are proportional to the corresponding interfacial tensions. For the case of equal interfacial tensions, we calculate a line tension that is proportional to the area of the small triangle.

  17. Depth Estimation and Specular Removal for Glossy Surfaces Using Point and Line Consistency with Light-Field Cameras.

    PubMed

    Tao, Michael W; Su, Jong-Chyi; Wang, Ting-Chun; Malik, Jitendra; Ramamoorthi, Ravi

    2016-06-01

    Light-field cameras have now become available in both consumer and industrial applications, and recent papers have demonstrated practical algorithms for depth recovery from a passive single-shot capture. However, current light-field depth estimation methods are designed for Lambertian objects and fail or degrade for glossy or specular surfaces. The standard Lambertian photoconsistency measure considers the variance of different views, effectively enforcing point-consistency, i.e., that all views map to the same point in RGB space. This variance or point-consistency condition is a poor metric for glossy surfaces. In this paper, we present a novel theory of the relationship between light-field data and reflectance from the dichromatic model. We present a physically-based and practical method to estimate the light source color and separate specularity. We present a new photo consistency metric, line-consistency, which represents how viewpoint changes affect specular points. We then show how the new metric can be used in combination with the standard Lambertian variance or point-consistency measure to give us results that are robust against scenes with glossy surfaces. With our analysis, we can also robustly estimate multiple light source colors and remove the specular component from glossy objects. We show that our method outperforms current state-of-the-art specular removal and depth estimation algorithms in multiple real world scenarios using the consumer Lytro and Lytro Illum light field cameras.

  18. Hybridization of downregulated-COMT transgenic switchgrass lines with field-selected switchgrass for improved biomass traits

    SciTech Connect

    Baxter, Holly L.; Alexander, Lisa W.; Mazarei, Mitra; Haynes, Ellen; Turner, Geoffrey B.; Sykes, Robert W.; Decker, Stephen R.; Davis, Mark F.; Dixon, Richard A.; Wang, Zeng-Yu; Neal Stewart, C.

    2016-01-21

    Transgenic switchgrass (Panicum virgatum L.) has been produced for improved cell walls for biofuels. For instance, downregulated caffeic acid 3-O-methyltransferase (COMT) switchgrass produced significantly more biomass and biofuel than the non-transgenic progenitor line. In this present study we sought to further improve biomass characteristics by crossing the downregulated COMT T1 lines with high-yielding switchgrass accessions in two genetic backgrounds ('Alamo' and 'Kanlow'). Crosses and T2 progeny analyses were made under greenhouse conditions to assess maternal effects, plant morphology and yield, and cell wall traits. Female parent type influenced morphology, but had no effect on cell wall traits. T2 hybrids produced with T1 COMT-downregulated switchgrass as the female parent were taller, produced more tillers, and produced 63% more biomass compared with those produced using the field selected accession as the female parent. Transgene status (presence or absence of transgene) influenced both growth and cell wall traits. T2 transgenic hybrids were 7% shorter 80 days after sowing and produced 43% less biomass than non-transgenic null-segregant hybrids. Cell wall-related differences included lower lignin content, reduced syringyl-to-guaiacyl (S/G) lignin monomer ratio, and a 12% increase in total sugar release in the T2 transgenic hybrids compared to non-transgenic null segregants. This is the first study to evaluate the feasibility of transferring the low-recalcitrance traits associated with a transgenic switchgrass line into high-yielding field varieties in an attempt to improve growth-related traits. Lastly, our results provide insights into the possible improvement of switchgrass productivity via biotechnology paired with plant breeding.

  19. Hybridization of downregulated-COMT transgenic switchgrass lines with field-selected switchgrass for improved biomass traits

    DOE PAGES

    Baxter, Holly L.; Alexander, Lisa W.; Mazarei, Mitra; ...

    2016-01-21

    Transgenic switchgrass (Panicum virgatum L.) has been produced for improved cell walls for biofuels. For instance, downregulated caffeic acid 3-O-methyltransferase (COMT) switchgrass produced significantly more biomass and biofuel than the non-transgenic progenitor line. In this present study we sought to further improve biomass characteristics by crossing the downregulated COMT T1 lines with high-yielding switchgrass accessions in two genetic backgrounds ('Alamo' and 'Kanlow'). Crosses and T2 progeny analyses were made under greenhouse conditions to assess maternal effects, plant morphology and yield, and cell wall traits. Female parent type influenced morphology, but had no effect on cell wall traits. T2 hybrids producedmore » with T1 COMT-downregulated switchgrass as the female parent were taller, produced more tillers, and produced 63% more biomass compared with those produced using the field selected accession as the female parent. Transgene status (presence or absence of transgene) influenced both growth and cell wall traits. T2 transgenic hybrids were 7% shorter 80 days after sowing and produced 43% less biomass than non-transgenic null-segregant hybrids. Cell wall-related differences included lower lignin content, reduced syringyl-to-guaiacyl (S/G) lignin monomer ratio, and a 12% increase in total sugar release in the T2 transgenic hybrids compared to non-transgenic null segregants. This is the first study to evaluate the feasibility of transferring the low-recalcitrance traits associated with a transgenic switchgrass line into high-yielding field varieties in an attempt to improve growth-related traits. Lastly, our results provide insights into the possible improvement of switchgrass productivity via biotechnology paired with plant breeding.« less

  20. Hybridization of downregulated-COMT transgenic switchgrass lines with field-selected switchgrass for improved biomass traits

    SciTech Connect

    Baxter, Holly L.; Alexander, Lisa W.; Mazarei, Mitra; Haynes, Ellen; Turner, Geoffrey B.; Sykes, Robert W.; Decker, Stephen R.; Davis, Mark F.; Dixon, Richard A.; Wang, Zeng-Yu; Neal Stewart, C.

    2016-01-21

    Transgenic switchgrass (Panicum virgatum L.) has been produced for improved cell walls for biofuels. For instance, downregulated caffeic acid 3-O-methyltransferase (COMT) switchgrass produced significantly more biomass and biofuel than the non-transgenic progenitor line. In the present study we sought to further improve biomass characteristics by crossing the downregulated COMT T1 lines with high-yielding switchgrass accessions in two genetic backgrounds ('Alamo' and 'Kanlow'). Crosses and T2 progeny analyses were made under greenhouse conditions to assess maternal effects, plant morphology and yield, and cell wall traits. Female parent type influenced morphology, but had no effect on cell wall traits. T2 hybrids produced with T1 COMT-downregulated switchgrass as the female parent were taller, produced more tillers, and produced 63% more biomass compared with those produced using the field selected accession as the female parent. Transgene status (presence or absence of transgene) influenced both growth and cell wall traits. T2 transgenic hybrids were 7% shorter 80 days after sowing and produced 43% less biomass than non-transgenic null-segregant hybrids. Cell wall-related differences included lower lignin content, reduced syringyl-to-guaiacyl (S/G) lignin monomer ratio, and a 12% increase in total sugar release in the T2 transgenic hybrids compared to non-transgenic null segregants. This is the first study to evaluate the feasibility of transferring the low-recalcitrance traits associated with a transgenic switchgrass line into high-yielding field varieties in an attempt to improve growth-related traits. Our results provide insights into the possible improvement of switchgrass productivity via biotechnology paired with plant breeding.

  1. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  2. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  3. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  4. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  5. 43 CFR 420.3 - Adjacent lands.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Adjacent lands. 420.3 Section 420.3 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR OFF-ROAD VEHICLE USE § 420.3 Adjacent lands. When administratively feasible, the regulation of...

  6. The magnetic field of an isolated neutron star from X-ray cyclotron absorption lines.

    PubMed

    Bignami, G F; Caraveo, P A; De Luca, A; Mereghetti, S

    2003-06-12

    Isolated neutron stars are highly magnetized, fast-rotating objects that form as an end point of stellar evolution. They are directly observable in X-ray emission, because of their high surface temperatures. Features in their X-ray spectra could in principle reveal the presence of atmospheres, or be used to estimate the strength of their magnetic fields through the cyclotron process, as is done for X-ray binaries. Almost all isolated neutron star spectra observed so far appear as featureless thermal continua. The only exception is 1E1207.4-5209 (refs 7-9), where two deep absorption features have been detected, but with insufficient definition to permit unambiguous interpretation. Here we report a long X-ray observation of the same object in which the star's spectrum shows three distinct features, regularly spaced at 0.7, 1.4 and 2.1 keV, plus a fourth feature of lower significance, at 2.8 keV. These features vary in phase with the star's rotation. The logical interpretation is that they are features from resonant cyclotron absorption, which allows us to calculate a magnetic field strength of 8 x 10(10) G, assuming the absorption arises from electrons.

  7. Interplanetary Magnetic Field Line Mixing Deduced from Impulsive Solar Flare Particles.

    PubMed

    Mazur; Mason; Dwyer; Giacalone; Jokipii; Stone

    2000-03-20

    We have studied fine-scale temporal variations in the arrival profiles of approximately 20 keV nucleon-1 to approximately 2 MeV nucleon-1 ions from impulsive solar flares using instrumentation on board the Advanced Composition Explorer spacecraft at 1 AU between 1997 November and 1999 July. The particle events often had short-timescale ( approximately 3 hr) variations in their intensity that occurred simultaneously across all energies and were generally not in coincidence with any local magnetic field or plasma signature. These features appear to be caused by the convection of magnetic flux tubes past the observer that are alternately filled and devoid of flare ions even though they had a common flare source at the Sun. Thus, we have used the particles to study the mixing of the interplanetary magnetic field that is due to random walk. We deduce an average timescale of 3.2 hr for these features, which corresponds to a length of approximately 0.03 AU.

  8. Health effects of magnetic fields generated from power lines: new clues for an old puzzle.

    PubMed

    Comba, Pietro; Fazzo, Lucia

    2009-01-01

    Thirty years ago, Nancy Wertheimer and Ed Leeper published the first report on the association between childhood cancer and "electrical current configuration" of houses in Denver, Colorado. In 2001 the International Agency for Research on Cancer defined 50-60 Hz magnetic fields as "possibly carcinogenic to humans" because of the "limited evidence" of carcinogenicity of residential exposure relatively to childhood leukemia. With respect to health effects other than cancer, namely neurodegenerative disorders, miscarriage, subtle differences in the timing of melatonin release, altered autonomic control of the heart, and changes in the number of natural killer cells, some open questions still remain. Several authors recommended further investigation of the possible long-term effects of magnetic fields, focussing on populations experiencing high exposure levels. In this frame a research team of ISS searched for a suitable location to implement an epidemiological study aimed at a wide range of outcomes for which a priori hypotheses could be formulated. The recently published findings of this project showed an increase of primary and secondary malignant neoplasms, ischaemic disease and haematological diseases. Future studies should thus address the most exposed sectors of the population, take into account different outcomes (all neoplasms, neurodegenerative diseases, immunological disorders, specific cardiovascular effects) and follow research protocols that enable subsequent pooled analyses. A precautionary approach may provide the frame for decision making where the available resources for environmental remediation be prioritatively allocated to worst-off situations.

  9. Broad-line Reverberation in the Kepler-field Seyfert Galaxy Zw 229-015

    NASA Astrophysics Data System (ADS)

    Barth, Aaron J.; Nguyen, My L.; Malkan, Matthew A.; Filippenko, Alexei V.; Li, Weidong; Gorjian, Varoujan; Joner, Michael D.; Bennert, Vardha Nicola; Botyanszki, Janos; Cenko, S. Bradley; Childress, Michael; Choi, Jieun; Comerford, Julia M.; Cucciara, Antonino; da Silva, Robert; Duchêne, Gaspard; Fumagalli, Michele; Ganeshalingam, Mohan; Gates, Elinor L.; Gerke, Brian F.; Griffith, Christopher V.; Harris, Chelsea; Hintz, Eric G.; Hsiao, Eric; Kandrashoff, Michael T.; Keel, William C.; Kirkman, David; Kleiser, Io K. W.; Laney, C. David; Lee, Jeffrey; Lopez, Liliana; Lowe, Thomas B.; Moody, J. Ward; Morton, Alekzandir; Nierenberg, A. M.; Nugent, Peter; Pancoast, Anna; Rex, Jacob; Rich, R. Michael; Silverman, Jeffrey M.; Smith, Graeme H.; Sonnenfeld, Alessandro; Suzuki, Nao; Tytler, David; Walsh, Jonelle L.; Woo, Jong-Hak; Yang, Yizhe; Zeisse, Carl

    2011-05-01

    The Seyfert 1 galaxy Zw 229-015 is among the brightest active galaxies being monitored by the Kepler mission. In order to determine the black hole mass in Zw 229-015 from Hβ reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad Hβ flux. From cross-correlation measurements, we find that the Hβ light curve has a rest-frame lag of 3.86+0.69 -0.90 days with respect to the V-band continuum variations. We also measure reverberation lags for Hα and Hγ and find an upper limit to the Hδ lag. Combining the Hβ lag measurement with a broad Hβ width of σline = 1590 ± 47 km s-1 measured from the rms variability spectrum, we obtain a virial estimate of M BH = 1.00+0.19 -0.24 × 107 M sun for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei.

  10. BROAD-LINE REVERBERATION IN THE KEPLER-FIELD SEYFERT GALAXY Zw 229-015

    SciTech Connect

    Barth, Aaron J.; Nguyen, My L.; Malkan, Matthew A.; Filippenko, Alexei V.; Li, Weidong; Cenko, S. Bradley; Choi, Jieun; Duchene, Gaspard; Ganeshalingam, Mohan; Gorjian, Varoujan; Joner, Michael D.; Bennert, Vardha Nicola; Botyanszki, Janos; Childress, Michael; Cucciara, Antonino; Comerford, Julia M.; Da Silva, Robert; Gates, Elinor L.; Gerke, Brian F.

    2011-05-10

    The Seyfert 1 galaxy Zw 229-015 is among the brightest active galaxies being monitored by the Kepler mission. In order to determine the black hole mass in Zw 229-015 from H{beta} reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad H{beta} flux. From cross-correlation measurements, we find that the H{beta} light curve has a rest-frame lag of 3.86{sup +0.69}{sub -0.90} days with respect to the V-band continuum variations. We also measure reverberation lags for H{alpha} and H{gamma} and find an upper limit to the H{delta} lag. Combining the H{beta} lag measurement with a broad H{beta} width of {sigma}{sub line} = 1590 {+-} 47 km s{sup -1} measured from the rms variability spectrum, we obtain a virial estimate of M{sub BH} = 1.00{sup +0.19}{sub -0.24} x 10{sup 7} M{sub sun} for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei.

  11. The Bottom Line: Cable Telegraphy and the Rise of Field Theory in the Victorian British Empire

    NASA Astrophysics Data System (ADS)

    Hunt, Bruce

    The networks of telegraph wires and undersea cables that began to spread across the world in the 1840s and 1850s had far-reaching effects on commerce and the dissemination of news. They also had deep effects on electrical science. In this paper, I will argue that what might at first appear to be a prime example of pure science--the development of electromagnetic field theory in Britain in the middle decades of the 19th century--was in fact driven in important ways by developments in the telegraph industry, particularly British scientists' and engineers' encounters with puzzling new phenomenon of the `retardation' of signals that turned up on underground wires and undersea cables in the early 1850s.

  12. Effect of low frequency (LF) electric fields on gene expression of a bone human cell line.

    PubMed

    Caputo, Mariella; Zirpoli, Hylde; De Rosa, Maria Caterina; Rescigno, Tania; Chiadini, Francesco; Scaglione, Antonio; Stellato, Claudia; Giurato, Giorgio; Weisz, Alessandro; Tecce, Mario Felice; Bisceglia, Bruno

    2014-12-01

    We evaluated the effects, on cultured human SaOS-2 cells, of exposures to the low frequency (LF) electric signal (60 kHz sinusoidal wave, 24.5 V peak-to-peak voltage, amplitude modulated by a 12.5 Hz square wave, 50% duty cycle) from an apparatus of current clinical use in bone diseases requiring regenerating processes. Cells in flasks were exposed to a capacitively coupled electric field giving electric current density in the sample of 4 µA/cm(2). The whole expressed cellular mRNAs were systematically analyzed by "DNA microchips" technology to identify all individual species quantitatively affected by field exposure. Comparisons were made between RNA samples from exposed and control sham-exposed cells. Results indicated that immediately and 4 h after exposure there were almost no differentially modulated mRNA species. However, samples obtained at 24 h after exposure showed a small number of limitedly differential signals (7 down-regulated and 3 up-regulated with a cut-off value of ±1.5; 38 and 11, respectively, with a cut-off value of ±1.3), which included mostly mRNA encoding transcription factors and DNA binding proteins. Nevertheless, in identical experimental conditions, we previously demonstrated enzymatic changes of alkaline phosphatase occurring immediately after exposure and declining in a few hours. Therefore, since enzymatic changes occur before those observed at gene regulation level, it is conceivable that only earlier effects are directly due the treatment and then these effects are later able to affect gene expression only indirectly.

  13. Integral field spectroscopy of planetary nebulae: mapping the line diagnostics and hydrogen-poor zones with VLT FLAMES

    NASA Astrophysics Data System (ADS)

    Tsamis, Y. G.; Walsh, J. R.; Péquignot, D.; Barlow, M. J.; Danziger, I. J.; Liu, X.-W.

    2008-05-01

    Results from the first dedicated study of Galactic planetary nebulae (PNe) by means of optical integral field spectroscopy with the Very Large Telescope Fibre Large Array Multi Element Spectrograph Argus integral field unit are presented. Three typical Galactic disc PNe have been mapped with the 11.5 × 7.2-arcsec2 Argus array: 2D spectral maps of the main shell of NGC5882 and of large areas of NGC 6153 and NGC 7009 with 297 spatial pixels per target were obtained at subarcsec resolutions. A corresponding number of 297 spectra per target were obtained in the 396.4-507.8nm range. Spatially resolved maps of emission lines and of nebular physical properties such as electron temperatures, densities and ionic abundances were produced. The abundances of helium and of doubly ionized carbon and oxygen, relative to hydrogen, were derived from optical recombination lines (ORLs), while those of O2+ were also derived from the classic collisionally excited lines (CELs). The occurrence of the abundance discrepancy problem, pertaining to oxygen, was investigated by mapping the ratio of ORL/CEL abundances for O2+ [the abundance discrepancy factor (ADF)] across the face of the PNe. The ADF varies between targets and also with position within the targets, attaining values of ~40 in the case of NGC 6153 and ~30 in the case of NGC 7009. Correlations of the ADF with geometric distance from the central star and plasma surface brightness (for NGC 6153), as well as with [OIII] electron temperature, plasma ionization state and other physical properties of the targets are established. Very small values of the temperature fluctuation parameter in the plane of the sky, t2A(O2+), are found in all cases. It is argued that these results provide further evidence for the existence in run-of-the-mill PNe of a distinct nebular component consisting of hydrogen-deficient, super-metal-rich plasma. The zones containing this posited component appear as undulations in the CII and OII ORL abundance

  14. SELFI: an object-based, Bayesian method for faint emission line source detection in MUSE deep field data cubes

    NASA Astrophysics Data System (ADS)

    Meillier, Céline; Chatelain, Florent; Michel, Olivier; Bacon, Roland; Piqueras, Laure; Bacher, Raphael; Ayasso, Hacheme

    2016-04-01

    We present SELFI, the Source Emission Line FInder, a new Bayesian method optimized for detection of faint galaxies in Multi Unit Spectroscopic Explorer (MUSE) deep fields. MUSE is the new panoramic integral field spectrograph at the Very Large Telescope (VLT) that has unique capabilities for spectroscopic investigation of the deep sky. It has provided data cubes with 324 million voxels over a single 1 arcmin2 field of view. To address the challenge of faint-galaxy detection in these large data cubes, we developed a new method that processes 3D data either for modeling or for estimation and extraction of source configurations. This object-based approach yields a natural sparse representation of the sources in massive data fields, such as MUSE data cubes. In the Bayesian framework, the parameters that describe the observed sources are considered random variables. The Bayesian model leads to a general and robust algorithm where the parameters are estimated in a fully data-driven way. This detection algorithm was applied to the MUSE observation of Hubble Deep Field-South. With 27 h total integration time, these observations provide a catalog of 189 sources of various categories and with secured redshift. The algorithm retrieved 91% of the galaxies with only 9% false detection. This method also allowed the discovery of three new Lyα emitters and one [OII] emitter, all without any Hubble Space Telescope counterpart. We analyzed the reasons for failure for some targets, and found that the most important limitation of the method is when faint sources are located in the vicinity of bright spatially resolved galaxies that cannot be approximated by the Sérsic elliptical profile. The software and its documentation are available on the MUSE science web service (muse-vlt.eu/science).

  15. Operational parameter fields in hyperbaric plasma keyhole welding of mild steel line pipe

    SciTech Connect

    Hoffmeister, H.; Huismann, G.; Sommer, U.; Knagenhjelm, H.O.

    1996-12-01

    Based on recent work on orbital plasma keyhole welding of Duplex Stainless Steels and Low Carbon Martensitic 12--13% Cr-Steels, the capability of the plasma keyhole process for hyperbaric positional welding is explored. Based on respective nozzle geometry development, constant position welding of 100 mm OD 5 mm wall thickness St 35 pipe test pieces is carried out at constant welding speeds of 3mm/s at various constant currents and plasma Argon gas flow rates. As a result, the operational parameter fields are basically limited by lack of penetration (LOP) at too low gas flows and cutting (CT) together with dropping at too high gas flow rates. Based on present hyperbaric specifications for fabrication, limiting conditions for minimum root weld widths of 3mm and maximum root reinforcements of 2mm are established, for 11 and 41 bar as well as for the 3h, 6h and 12 h position. As common operating parameter sets for all positions, 135 A and 1.5 l/min plasma gas flow and 120 A and 1.8 l/min plasma gas flow are identified for 11 bar and 41 bar respectively.

  16. On-line Sample Preconcentration Using Field-amplified Stacking Injection in Microchip Capillary Electrophoresis

    PubMed Central

    Gong, Maojun; Wehmeyer, Kenneth R.; Limbach, Patrick A.; Arias, Francisco; Heineman, William R.

    2008-01-01

    Previous reports describing sample stacking on microchip capillary electrophoresis (μCE) have regarded the microchip channels as a closed system and treated the bulk flow as in traditional capillary electrophoresis. This work demonstrates that the flows arising from the cross region should be investigated as an open system. It is shown that the pressure-driven flows into or from the branch channels due to bulk velocity mismatch in the main channel should not be neglected but can be used for liquid transportation in the channels. Based on these concepts, a sample preconcentration scheme was developed in a commercially available glass, single-cross chip for μCE. Similar to field-amplified stacking injection in traditional CE, a low conductivity sample buffer plug was introduced into the separation channel immediately before the negatively charged analyte molecules were injected. The detection sensitivity was improved by 94-, 108- and 160-fold for fluorescein-5-isothiocyanate, fluorescein disodium and 5-carboxyfluorescein, respectively, relative to a traditional pinched injection. The calibration curves for fluorescein and 5-carboxyfluorescein demonstrated good linearity in the concentration range (1 to 60 nM) investigated with acceptable reproducibility of migration time and peak height and area ratios (4 to 5% RSD). This preconcentration scheme will be of particular significance to the practical use of μCE in the emerging miniaturized analytical instrumentation. PMID:16737230

  17. Comparison of on-line detectors for field flow fractionation analysis of nanomaterials.

    PubMed

    Bednar, A J; Poda, A R; Mitrano, D M; Kennedy, A J; Gray, E P; Ranville, J F; Hayes, C A; Crocker, F H; Steevens, J A

    2013-01-30

    Characterization of nanomaterials must include analysis of both size and chemical composition. Many analytical techniques, such as dynamic light scattering (DLS), are capable of measuring the size of suspended nanometer-sized particles, yet provide no information on the composition of the particle. While field flow fractionation (FFF) is a powerful nanoparticle sizing technique, common detectors used in conjunction with the size separation, including UV, light-scattering, and fluorescence spectroscopy, do not provide the needed particle compositional information. Further, these detectors do not respond directly to the mass concentration of nanoparticles. The present work describes the advantages achieved when interfacing sensitive and elemental specific detectors, such as inductively coupled plasma atomic emission spectroscopy and mass spectrometry, to FFF separation analysis to provide high resolution nanoparticle sizing and compositional analysis at the μg/L concentration level, a detection at least 10-100-fold lower than DLS or FFF-UV techniques. The full benefits are only achieved by utilization of all detector capabilities, such as dynamic reaction cell (DRC) ICP-MS. Such low-level detection and characterization capability is critical to nanomaterial investigations at biologically and environmentally relevant concentrations. The techniques have been modified and applied to characterization of all four elemental constituents of cadmium selenide-zinc sulfide core-shell quantum dots, and silver nanoparticles with gold seed cores. Additionally, sulfide coatings on silver nanoparticles can be detected as a potential means to determine environmental aging of nanoparticles.

  18. Anomalous, quasilinear, and percolative regimes for magnetic-field-line transport in axially symmetric turbulence

    PubMed

    Zimbardo; Veltri; Pommois

    2000-02-01

    We studied a magnetic turbulence axisymmetric around the unperturbed magnetic field for cases having different ratios l( ||)/l( perpendicular). We find, in addition to the fact that a higher fluctuation level deltaB/B(0) makes the system more stochastic, that by increasing the ratio l( ||)/l( perpendicular) at fixed deltaB/B(0), the stochasticity increases. It appears that the different transport regimes can be organized in terms of the Kubo number R=(deltaB/B(0))(l( ||)/l( perpendicular)). The simulation results are compared with the two analytical limits, that is the percolative limit and the quasilinear limit. When R<1 weak chaos, closed magnetic surfaces, and anomalous transport regimes are found. When R approximately 1 the diffusion regime is Gaussian, and the quasilinear scaling of the diffusion coefficient D( perpendicular) approximately (deltaB/B(0))(2) is recovered. Finally, for R>1 the percolation scaling of the diffusion coefficient D( perpendicular) approximately (deltaB/B(0))(0.7) is obtained.

  19. Magnetic fields dispersed by high-voltage power lines: an advanced evaluation method based on 3-D models of electrical lines and the territory.

    PubMed

    Andreuccetti, D; Zoppetti, N

    2004-01-01

    An advanced numerical evaluation tool is proposed for calculating the magnetic flux density dispersed by high-voltage power lines. When compared to existing software packages based on the application of standardized methods, this tool turned out to be particularly suitable for making accurate evaluations on vast portions of the territory, especially when the contribution of numerous aerial and/or underground lines must be taken into account. The aspects of the tool of greatest interest are (1) the interaction with an electronic archive of power lines, from which all the information necessary for the calculation is obtained; (2) the use of three-dimensional models of both the power lines and the territory crossed by these; (3) the direct interfacing with electronic cartography; and finally (4) the use of a representation procedure for the results that is based on contour maps. The tool had proven to be very useful especially for Environmental Impact Assessment procedures relative to new power lines.

  20. Transmitted sound field due to an impulsive line acoustic source bounded by a plate followed by a vortex sheet

    NASA Technical Reports Server (NTRS)

    Miura, T.; Chao, C. C.

    1980-01-01

    The propagation of sound due to a line acoustic source in the moving stream across a semiinfinite vortex sheet which trails from a rigid plate is examined in a linear theory for the subsonic case. A solution for the transmitted sound field is obtained with the aid of multiple integral transforms and the Wiener-Hopf technique for both the steady state (time harmonic) and initial value (impulsive source) situations. The contour of inverse transform and hence the decomposition of the functions are determined through causality and radiation conditions. The solution obtained satisfies causality and the full Kutta conditions. The transmitted sound field is composed of two waves in both the stady state and initial value problems. One is the wave scattered from the edge of the plate which is associated with the bow wave and the instability wave. These waves exist in the downstream sectors. The other is the wave transmitted through the vortex sheet which is also associated with the instability wave. Regional divisions of the transmitted sound field are identified.

  1. Effects of low frequency electric fields on synaptic integration in hippocampal CA1 pyramidal neurons: implications for power line emissions

    PubMed Central

    Cavarretta, Francesco; Carnevale, Nicholas T.; Tegolo, Domenico; Migliore, Michele

    2014-01-01

    The possible cognitive effects of low frequency external electric fields (EFs), such as those generated by power lines, are poorly understood. Their functional consequences for mechanisms at the single neuron level are very difficult to study and identify experimentally, especially in vivo. The major open problem is that experimental investigations on humans have given inconsistent or contradictory results, making it difficult to estimate the possible effects of external low frequency electric fields on cognitive functions. Here we investigate this issue with realistic models of hippocampal CA1 pyramidal neurons. Our findings suggest how and why EFs, with environmentally observed frequencies and intensities far lower than what is required for direct neural activation, can perturb dendritic signal processing and somatic firing of neurons that are crucially involved in cognitive tasks such as learning and memory. These results show that individual neuronal morphology, ion channel dendritic distribution, and alignment with the electric field are major determinants of overall effects, and provide a physiologically plausible explanation of why experimental findings can appear to be small and difficult to reproduce, yet deserve serious consideration. PMID:25346660

  2. Stark spectroscopy of atomic hydrogen balmer-alpha line for electric field measurement in plasmas by saturation spectroscopy

    NASA Astrophysics Data System (ADS)

    Nishiyama, S.; Katayama, K.; Nakano, H.; Goto, M.; Sasaki, K.

    2016-09-01

    Detailed structures of electric fields in sheath and pre-sheath regions of various plasmas are interested from the viewpoint of basic plasma physics. Several researchers observed Stark spectra of Doppler-broadened Rydberg states to evaluate electric fields in plasmas; however, these measurements needed high-power, expensive tunable lasers. In this study, we carried out another Stark spectroscopy with a low-cost diode laser system. We applied saturation spectroscopy, which achieves a Doppler-free wavelength resolution, to observe the Stark spectrum of the Balmer-alpha line of atomic hydrogen in the sheath region of a low-pressure hydrogen plasma. The hydrogen plasma was generated in an ICP source which was driven by on-off modulated rf power at 20 kHz. A planar electrode was inserted into the plasma. Weak probe and intense pump laser beams were injected into the plasma from the counter directions in parallel to the electrode surface. The laser beams crossed with a small angle above the electrode. The observed fine-structure spectra showed shifts, deformations, and/or splits when varying the distance between the observation position and the electrode surface. The detection limit for the electric field was estimated to be several tens of V/cm.

  3. Feasibility of gravity field recovery from GRACE line-of-sight (LOS) gradiometry observations using the torus approach

    NASA Astrophysics Data System (ADS)

    Xu, C.; Sideris, M. G.; Sneeuw, N.

    2007-12-01

    The dedicated satellite gravity field mission \\textsc{Grace} employs the concept of satellite-to-satellite tracking in low-low mode (\\textsc{sst}-ll). The ratio between the precise inter-satellite K-band range and the range acceleration (ρ/\\ddot{ρ}) can be treated approximately as a line-of-sight (\\textsc{los}) gradiometry observable. Theoretically, this observable has a similar pattern as the gravity gradient tensor along-track component Vxx. The \\textsc{Grace} \\textsc{los} gradiometry data from both real and simulated range and range acceleration observations are processed by the torus-based semi-analytical approach to recover the gravity field. The torus-based approach shows its efficiency in gravity field determination in terms of the time and storage requirements and its flexibility of dealing with any geopotential functional. Our preliminary results show that the estimated spherical harmonic coefficients are not accurate enough compared to a reference model. The major reason would be that the ≍ 220 km baseline of \\textsc{Grace} does not fulfill the \\textsc{los} gradiometry assumption of a sufficiently small baseline. Another possible reason is the additional error from interpolation, which can be improved by iteration.

  4. Late Quaternary history of the southwestern St. Lawrence Lowlands and adjacent Adirondack Highlands

    SciTech Connect

    Pair, D.L. . Dept. of Geology)

    1993-03-01

    The reconstruction of Late Wisconsinan ice retreat, proglacial lakes, and Champlain Sea history from the northwest Adirondack slope and adjacent St. Lawrence Lowlands is critical to the synthesis of a regional picture of deglacial events in the eastern Great Lakes region. Unfortunately, these same areas are well known for their limited exposures, landforms covered by thick forest, large tracts of land inaccessible to detailed field mapping, and the overall paucity of glacial materials preserved on upland surfaces. Despite these limitations, a model which utilizes multiple and field-truthed evidence has been used to designate areas where ice border deposits indicate a substantial recessional position. It employs the following criteria in this analysis: sedimentology and morphostratigraphy of morainal landform segments and related sediments; orientation and continuity of ice border drainage channels; and the relationship of ice borders and drainage systems to well documented local and regional water bodies which accompanied ice retreat. The results of this approach have provided a unique regional picture of deglaciation. Despite the inherent limitations of working in upland areas to reconstruct glacial events, detailed morphostratigraphic correlations based on multiple lines of evidence can yield important information. The positions of five former ice borders have been reconstructed from the available data. These ice margins correspond closely with those documented previously by others adjoining areas. This type of study, utilizing multiple and field-truthed lines of evidence, constitutes a tangible step towards understanding the nature and history of ice retreat along this portion of the Laurentide Ice Sheet.

  5. Effects of low intensity static electromagnetic radiofrequency fields on leiomyosarcoma and smooth muscle cell lines.

    PubMed

    Karkabounas, Spyridon; Havelas, Konstantinos; Kostoula, Olga K; Vezyraki, Patra; Avdikos, Antonios; Binolis, Jayne; Hatziavazis, George; Metsios, Apostolos; Verginadis, Ioannis; Evangelou, Angelos

    2006-01-01

    In this study we investigated the effects of low intensity static radiofrequency electromagnetic field (EMF) causing no thermal effects, on leiomyosarcoma cells (LSC), isolated from tumors of fifteen Wistar rats induced via a 3,4-benzopyrene injection. Electromagnetic resonance frequencies measurements and exposure of cells to static EMF were performed by a device called multi channel dynamic exciter 100 V1 (MCDE). The LSC were exposed to electromagnetic resonance radiofrequencies (ERF) between 10 kHz to 120 kHz, for 45 min. During a 24h period, after the exposure of the LSC to ERF, there was no inhibition of cells proliferation. In contrast, at the end of a 48 h incubation period, LSC proliferation dramatically decreased by more than 98% (P<0.001). At that time, the survived LSC were only 2% of the total cell population exposed to ERF, and under the same culture conditions showed significant decrease of proliferation. These cells were exposed once again to ERF for 45 min (totally 4 sessions of exposure, of 45 min duration each) and tested using a flow cytometer. Experiments as above were repeated five times. It was found that 45% of these double exposed to ERF, LSC (EMF cells) were apoptotic and only a small percentage 2%, underwent mitosis. In order to determinate their metastatic potential, these EMF cells were also counted and tested by an aggregometer for their ability to aggregate platelets and found to maintain this ability., since they showed no difference in platelet aggregation ability compared to the LSC not exposed to ERF (control cells). In conclusion, exposure of LSC to specific ERF, decreases their proliferation rate and induces cell apoptosis. Also, the LSC that survived after exposed to ERF, had a lower proliferation rate compared to the LSC controls (P<0.05) but did not loose their potential for metastases (platelet aggregation ability). The non-malignant SMC were not affected by the EMF exposure (P<0.4). The specific ERF generated from the MCDE

  6. Study on reduction in electric field, charged voltage, ion current and ion density under HVDC transmission lines by parallel shield wires

    SciTech Connect

    Amano, Y.; Sunaga, Y.

    1989-04-01

    An important problem in the design and operation of HVDC transmission lines is to reduce electrical field effects such as ion flow electrification of objects, electric field, ion current and ion density at ground level in the vicinity of HVDC lines. Several models of shield wire were tested with the Shiobara HVDC test line. The models contain typical stranded wires that are generally used to reduce field effects at ground level, neutral conductors placed at lower parts of the DC line, and an ''earth corona model'' to cancel positive or negative ions intentionally by generating ions having opposite polarity to ions flowing into the wire. This report describes the experimental results of the effects of these shield wires and a method to predict shielding effects.

  7. High I on/I off current ratio graphene field effect transistor: the role of line defect.

    PubMed

    Tajarrod, Mohammad Hadi; Saghai, Hassan Rasooli

    2015-01-01

    The present paper casts light upon the performance of an armchair graphene nanoribbon (AGNR) field effect transistor in the presence of one-dimensional topological defects. The defects containing 5-8-5 sp(2)-hybridized carbon rings were placed in a perfect graphene sheet. The atomic scale behavior of the transistor was investigated in the non-equilibrium Green's function (NEGF) and tight-binding Hamiltonian frameworks. AGNRFET basic terms such as the on/off current, transconductance and subthreshold swing were investigated along with the extended line defect (ELD). The results indicated that the presence of ELDs had a significant effect on the parameters of the GNRFET. Compared to conventional transistors, the increase of the I on/I off ratio in graphene transistors with ELDs enhances their applicability in digital devices.

  8. Approximate analytical solution for nuclear matter in a mean-field Walecka model and Coester line behavior

    SciTech Connect

    Delfino, A.; Silva, J.B.; Malheiro, M.

    2006-03-15

    We study nuclear matter, at the mean-field approximation, by considering as equal the values of the scalar and the vector density in the Walecka model, which is a very reasonable approximation up to the nuclear matter saturation density. It turns out that the model has an analytical solution for the scalar and vector couplings as functions only of the nuclear matter density and binding energy. The nuclear matter properties are very close to the original version of the model. This solution allows us to show that the correlation between the binding energy and the saturation density is Coester line like. The liquid-gas phase transition is also studied and the critical and flash temperatures are again very similar to the original ones.

  9. Signatures of the nightside open closed magnetic field-line boundary during moderately disturbed conditions and ionospheric substorms

    NASA Astrophysics Data System (ADS)

    Parkinson, M. L.; Pinnock, M.; Dyson, P. L.; Devlin, J. C.

    The comparatively low latitude of the Tasman International Geospace Environment Radar (TIGER) (147.2°E, 43.4°S, geographic; -54.6°Λ), a Southern Hemisphere HF SuperDARN radar, facilitates the observation of extensive backscatter from decametre-scale irregularities drifting in the auroral and polar cap ionosphere in the midnight sector. The radar often detects a persistent, sharp increase over ˜90 km of range in line-of-sight Doppler velocity spread, or spectral width, from <50 m s -1 at lower latitude to >200 m s -1 at higher latitude. It was previously shown that for moderately disturbed conditions in the pre-midnight sector, the location of the spectral width boundary (SWB) corresponds to the poleward edge of the auroral oval, as determined from energy spectra of precipitating particles measured on board Defense Meteorology Satellite Program satellites. This implies the radar SWB is a proxy for the open-closed magnetic field-line boundary (OCB) under these particular conditions. Here we investigate whether the radar SWB is aligned with the satellite OCB under a broader range of geomagnetic conditions including small to moderate substorms occurring in the pre- and post-magnetic midnight sectors. The behaviour of the SWB can be reconciled with the spatial and temporal variations of energetic particle precipitation throughout the substorm cycle.

  10. DNA damage, cell kinetics and ODC activities studied in CBA mice exposed to electromagnetic fields generated by transmission lines.

    PubMed

    Svedenstål, B M; Johanson, K J; Mattsson, M O; Paulsson, L E

    1999-01-01

    CBA mice were exposed outdoors to 50 Hz electromagnetic fields (EMF), with a flux density of about 8 microT rms (root mean square), generated by a 220 kV transmission line. Assays were performed in order to investigate, the possible genotoxic effects after 11, 20 and 32 days of exposure, as well as the effects on body weight, leukocytes, erythrocytes, and the level of ornithine decarboxylase (ODC) activity in spleen and testis. DNA migration was studied on brain cells by single cell electrophoresis (comet assay). After 32 days of exposure a highly significant change of the tail/head ratio of the comets was observed (p < 0.001), showing DNA-damage. Further, a decreased number of mononuclear leukocytes (0.02 < p < 0.05) was observed in mice EMF-exposed for 20 days. In summary, our data indicate that transmission lines of this type may induce genotoxic effects in mice, seen as changes in the DNA migration. These results might have an important implication for health effects.

  11. Hybrid Simulation of Supersonic Flow of Weakly Ionized Plasma along Open Field Magnetic Line Effect of Background Pressure

    NASA Astrophysics Data System (ADS)

    Laosunthara, Ampan; Akatsuka, Hiroshi

    2016-09-01

    In previous study, we experimentally examined physical properties of supersonic flow of weakly ionized expanding arc-jet plasma through an open magnetic field line (Bmax 0.16T). We found supersonic velocity of helium plasma up to Mach 3 and the space potential drop at the end of the magnets. To understand the plasma in numerical point of view, the flows of ion and neutral are treated by particle-based Direct Simulation Monte Carlo (DSMC) method, electron is treated as a fluid. The previous numerical study, we assumed 2 conditions. Ion and electron temperatures were the same (LTE condition). Ion and electron velocities were the same (current-free condition). We found that ion velocity decreased by collision with residual gas molecules (background pressure). We also found that space potential changing with background pressure. In other words, it was indicated that electric field exists and the current-free assumption is not proper. In this study, we add electron continuity and electron momentum equations to obtain electron velocity and space potential. We find that space potential changing with background pressure slightly. It is indicated that electron is essential to space potential formation than ion.

  12. The effect of line damping, magneto-optics and parasitic light on the derivation of sunspot vector magnetic fields

    NASA Technical Reports Server (NTRS)

    Skumanich, A.; Lites, B. W.

    1985-01-01

    The least square fitting of Stokes observations of sunspots using a Milne-Eddington-Unno model appears to lead, in many circumstances, to various inconsistencies such as anomalously large doppler widths and, hence, small magnetic fields which are significantly below those inferred solely from the Zeeman splitting in the intensity profile. It is found that the introduction of additional physics into the model such as the inclusion of damping wings and magneto-optic birefrigence significantly improves the fit to Stokes parameters. Model fits excluding the intensity profile, i.e., of both magnitude as well as spectral shape of the polarization parameters alone, suggest that parasitic light in the intensity profile may also be a source of inconsistencies. The consequences of the physical changes on the vector properties of the field derived from the Fe I lambda 6173 line for the 17 November 1975 spot as well as on the thermodynamic state are discussed. A Doppler width delta lambda (D) - 25mA is bound to be consistent with a low spot temperature and microturbulence, and a damping constant of a = 0.2.

  13. Crystal-field analysis and calculation of two-photon absorption line strengths of dicesium sodium hexachlorogadolinate(III).

    PubMed

    Duan, Chang-Kui; Tanner, Peter A

    2010-03-31

    The crystal-field energy level calculation of the 4f(7) ion Gd(3+) in the crystal Cs(2)NaGdCl(6) has fitted 45 levels with standard deviation 12 cm(-1), with the energy parameters being consistent with those from other studies. The resulting eigenvectors have been employed in the calculation of two-photon absorption (TPA) intensities of transitions from the electronic ground state (8)S(7/2) to the crystal-field levels of excited (6)P, (6)I and (6)D multiplet terms. The TPA line strengths are highly polarization dependent and exhibit striking differences for linearly polarized incident radiation compared with circularly polarized radiation. The relative intensities are compared with those available from previous experimental studies and some reassignments have been made. Good agreement of calculated and experimental TPA spectra is found, except for the intensity ratio of the transitions to (6)P(7/2) or (6)P(5/2) compared with that to (6)P(3/2), for linear and circular polarizations, where the calculation overestimates the ratio. Reasons for this disagreement are presented.

  14. Constraining possible variations of the fine structure constant in strong gravitational fields with the Kα iron line

    SciTech Connect

    Bambi, Cosimo

    2014-03-01

    In extensions of general relativity and in theories aiming at unifying gravity with the forces of the Standard Model, the value of the ''fundamental constants'' is often determined by the vacuum expectation value of new fields, which may thus change in different backgrounds. Variations of fundamental constants with respect to the values measured today in laboratories on Earth are expected to be more evident on cosmological timescales and/or in strong gravitational fields. In this paper, I show that the analysis of the Kα iron line observed in the X-ray spectrum of black holes can potentially be used to probe the fine structure constant α in gravitational potentials relative to Earth of Δφ ≈ 0.1. At present, systematic effects not fully under control prevent to get robust and stringent bounds on possible variations of the value of α with this technique, but the fact that current data can be fitted with models based on standard physics already rules out variations of the fine structure constant larger than some percent.

  15. An area-preserving mapping in natural canonical coordinates for magnetic field line trajectories in the DIII-D tokamak

    NASA Astrophysics Data System (ADS)

    Punjabi, Alkesh

    2009-11-01

    The new approach of integrating magnetic field line trajectories in natural canonical coordinates (Punjabi and Ali 2008 Phys. Plasmas 15 122502) in divertor tokamaks is used for the DIII-D tokamak (Luxon and Davis1985 Fusion Technol. 8 441). The equilibrium EFIT data (Evans et al 2004 Phys. Rev. Lett. 92 235003, Lao et al 2005 Fusion Sci. Technol. 48 968) for the DIII-D tokamak shot 115467 at 3000 ms is used to construct the equilibrium generating function (EGF) for the DIII-D in natural canonical coordinates. The EGF gives quite an accurate representation of the closed and open equilibrium magnetic surfaces near the separatrix, the separatrix, the position of the X-point and the poloidal magnetic flux inside the ideal separatrix in the DIII-D. The equilibrium safety factor q from the EGF is somewhat smaller than the DIII-D EFIT q profile. The equilibrium safety factor is calculated from EGF as described in the previous paper (Punjabi and Ali 2008 Phys. Plasmas 15 122502). Here the safety factor for the open surfaces in the DIII-D is calculated. A canonical transformation is used to construct a symplectic mapping for magnetic field line trajectories in the DIII-D in natural canonical coordinates. The map is explored in more detail in this work, and is used to calculate field line trajectories in the DIII-D tokamak. The continuous analogue of the map does not distort the DIII-D magnetic surfaces in different toroidal planes between successive iterations of the map. The map parameter k can represent effects of magnetic asymmetries in the DIII-D. These effects in the DIII-D are illustrated. The DIII-D map is then used to calculate stochastic broadening of the ideal separatrix from the topological noise and field errors, the low mn, the high mn and peeling-ballooning magnetic perturbations in the DIII-D. The width of the stochastic layer scales as 1/2 power of amplitude with a maximum deviation of 6% from the Boozer-Rechester scaling (Boozer and Rechester 1978 Phys

  16. Differential microstrip lines with reduced crosstalk and common mode effect based on spoof surface plasmon polaritons.

    PubMed

    Wu, Jin Jei; Hou, Da Jun; Liu, Kexin; Shen, Linfang; Tsai, Chi An; Wu, Chien Jang; Tsai, Dichi; Yang, Tzong-Jer

    2014-11-03

    We apply the concept of spoof surface plasmon polaritons (SPPs) to the design of differential microstrip lines by introducing periodic subwavelength corrugations on their edges. The dispersion relation and field distribution of those lines are analyzed numerically. And then through designing practical coupling circuits, we found that compared with conventional differential microstrip lines, the electromagnetic field can be strongly confined inside the grooves of the corrugated microstrip lines, so the crosstalk between the differential pair and the adjacent microstrip lines is greatly reduced, and the conversion from the differential signal to the common mode signal can also be effectively suppressed. The propagation length of those lines is also very long in a wide band. Moreover, the experimental results in time domain demonstrate those lines perform very well in high-speed circuit. Therefore, those novel kinds of spoof SPPs based differential microstrip lines can be widely utilized in high-density microwave circuits and guarantee signal integrity in high-speed systems.

  17. Using BRDFs for accurate albedo calculations and adjacency effect corrections

    SciTech Connect

    Borel, C.C.; Gerstl, S.A.W.

    1996-09-01

    In this paper the authors discuss two uses of BRDFs in remote sensing: (1) in determining the clear sky top of the atmosphere (TOA) albedo, (2) in quantifying the effect of the BRDF on the adjacency point-spread function and on atmospheric corrections. The TOA spectral albedo is an important parameter retrieved by the Multi-angle Imaging Spectro-Radiometer (MISR). Its accuracy depends mainly on how well one can model the surface BRDF for many different situations. The authors present results from an algorithm which matches several semi-empirical functions to the nine MISR measured BRFs that are then numerically integrated to yield the clear sky TOA spectral albedo in four spectral channels. They show that absolute accuracies in the albedo of better than 1% are possible for the visible and better than 2% in the near infrared channels. Using a simplified extensive radiosity model, the authors show that the shape of the adjacency point-spread function (PSF) depends on the underlying surface BRDFs. The adjacency point-spread function at a given offset (x,y) from the center pixel is given by the integral of transmission-weighted products of BRDF and scattering phase function along the line of sight.

  18. Reservoir quality, sediment source, and regional aspects of Norphlet Formation, South State Line field, Greene County, Mississippi

    SciTech Connect

    Thomson, A.; Stancliffe, R.J.; Shew, R.D.

    1987-05-01

    South State Line field, discovered in 1970, is centrally located in the productive Jurassic Norphlet trend of the eastern Gulf Coast. The Norphlet Formation at South State Line has produced gas and condensate from normally pressured eolian sandstones at depths of more than 17,900 ft (5455 m). The 600-ft- (183-m) thick Norphlet Formation is composed of 100% sandstone and consists of two reservoir types: a poorer quality upper sandstone having low permeability (0.6 md) and a good-quality lower sandstone with better permeability (15.5 md). The upper sandstone exhibits tighter compaction of framework grains and more cement than the lower sandstone. Significantly, the upper sandstone contains authigenic illite (which promotes pressure solution), whereas the lower sandstone contains authigenic chlorite (which inhibits cementation and possibly pressure solution). On a regional scale, illite is the principal diagenetic clay mineral in the western area of the Norphlet trend (Mississippi to Texas), whereas chlorite is the principal diagenetic clay mineral in the east (Alabama to Florida). Not surprisingly, reservoir quality is poorer in the western portion of the trend. A comparison of framework grains in the upper and lower sandstones shows no significant compositional differences. Both are mature arkosic sandstones with a transitional-continental source (eastern Appalachians). No evidence was seen of a quartz-rich Ouachita or cratonic source. Volcanic and plutonic rock fragments are slightly more abundant in the lower sandstone, possibly reflecting a shifting of compositional terranes within a single source area along the eastern side of the Appalachians. The lower Norphlet sandstone may have been derived from Triassic volcanics, whereas the upper sandstone may have been derived from a more metamorphic source.

  19. On the time-course of adjacent and non-adjacent transposed-letter priming

    PubMed Central

    Ktori, Maria; Kingma, Brechtsje; Hannagan, Thomas; Holcomb, Phillip J.; Grainger, Jonathan

    2014-01-01

    We compared effects of adjacent (e.g., atricle-ARTICLE) and non-adjacent (e.g., actirle-ARTICLE) transposed-letter (TL) primes in an ERP study using the sandwich priming technique. TL priming was measured relative to the standard double-substitution condition. We found significantly stronger priming effects for adjacent transpositions than non-adjacent transpositions (with 2 intervening letters) in behavioral responses (lexical decision latencies), and the adjacent priming effects emerged earlier in the ERP signal, at around 200 ms post-target onset. Non-adjacent priming effects emerged about 50 ms later and were short-lived, being significant only in the 250-300 ms time-window. Adjacent transpositions on the other hand continued to produce priming in the N400 time-window (300-500 ms post-target onset). This qualitatively different pattern of priming effects for adjacent and non-adjacent transpositions is discussed in the light of different accounts of letter transposition effects, and the utility of drawing a distinction between positional flexibility and positional noise. PMID:25364497

  20. Use of a Field Portable X-Ray Fluorescence Analyzer for Environmental Exposure Assessment of a Neighborhood in Cairo, Egypt Adjacent to the Site of a Former Secondary Lead Smelter.

    PubMed

    Menrath, William; Zakaria, Yehia; El-Safty, Amal; Clark, C Scott; Roda, Sandy M; Elsayed, Essam; Lind, Caroline; Pesce, John; Peng, Hongying

    2015-01-01

    The objectives of this study are to demonstrate for the first time the use of a field portable X-Ray Fluorescence Analyzer (XRF) in a multi-media environmental survey and to use the survey results to determine if residual lead from a once-active secondary lead smelter in Cairo, Egypt, still posed a health risk to the residents when comparing results with US EPA standards. Results were analyzed to determine if relationships among the variables indicated that there were residual impacts of the former smelter. Samples collected inside and near a total of 194 dwellings were analyzed. The mean floor dust lead loading was 7.48 μg lead/ft(2). Almost 10% of the dwellings had at least one floor dust wipe sample that exceeded the United States Environmental Protection Agency's (USEPA) interior settled dust lead level of 40 μg lead/ft(2). The median paint lead level was 0.04 mg lead/cm(2). 17% of the dwellings had at least one interior paint sample that exceeded the USEPA standard of 1.0 mg lead/cm(2). Mean soil lead concentration in the study area was 458 ppm and 91 ppm outside the study area. Four of nine composite soil samples exceeded the US EPA limit for bare soil in play areas. Lead concentrations in samples collected in locations outside the study area did not exceed the limit. The highest concentration was in the plot closest to the smelter and may represent residual impact from the former smelter. Statistically significant relationships were not detected between interior floor dust lead loading and either interior paint lead loading or exterior dust lead concentration. Thus, no significant exposure from the former smelter was indicated by these analyses. This may have resulted from the time elapsed since the closing of the smelter and/or the relatively low paint lead levels. Further study is needed in other areas of Egypt near former and active lead smelters. Elevated levels of mercury and arsenic detected in soil samples do not appear to be related to the smelter

  1. Health responses to a new high-voltage power line route: design of a quasi-experimental prospective field study in the Netherlands

    PubMed Central

    2014-01-01

    Background New high-voltage power transmission lines will be introduced due to increasing demand for reliable and renewable energy supplies. Some residents associate non-specific health complaints with exposure to electromagnetic fields from nearby power lines. This study protocol describes the design and rationale of a prospective study investigating whether the introduction of a new power line triggers health responses in residents living nearby. Methods/Design The study is designed as a quasi-experimental field study with two pretests during the construction of a new power line route, and two posttests after it has been put into operation. Key outcomes are self-reported non-specific somatic and cognitive health complaints, and attribution of these health complaints to a power line. The main determinant is proximity to the new power line route. One member of every household (n = 2379) residing in close proximity (0-500 meters) to the overhead parts of a new power line route in the Netherlands is invited to participate, as well as a sample of household members (n = 2382) residing farther away (500-2000 meters). Multilevel analysis will be employed to test whether an increase in key outcome measures is related to proximity to the line. Longitudinal structural equation models will be applied to test to what extent health responses are mediated by psychosocial health mechanisms and moderated by negative oriented personality traits. Discussion This is the first study to investigate health responses to a new power line route in a prospective manner. The results will provide theoretical insight into psychosocial mechanisms operating during the introduction of an environmental health risk, and may offer suggestions to policymakers and other stakeholders for minimizing adverse health responses when introducing new high-voltage power lines. PMID:24606914

  2. Field-Lines-Threaded Model for: (1) the Low Solar Corona; (2) Electrons in the Transition Region; and (3) Solar Energetic Particle Acceleration and Transport

    NASA Astrophysics Data System (ADS)

    Sokolov, I.; van der Holst, B.; Jin, M.; Gombosi, T. I.; Taktakishvili, A.; Khazanov, G. V.

    2013-12-01

    In numerical simulations of the solar corona, both for the ambient state and especially for dynamical processes the most computational resources are spent for maintaining the numerical solution in the Low Solar Corona and in the transition region, where the temperature gradients are very sharp and the magnetic field has a complicated topology. The degraded computational efficiency is caused by the need in a highest resolution as well as the use of the fully three-dimensional implicit solver for electron heat conduction. On the other hand, the physical nature of the processes involved is rather simple (which still does not facilitate the numerical methods) as long as the heat fluxes as well as slow plasma motional velocities are aligned with the magnetic field. The Alfven wave turbulence, which is often believed to be the main driver of the solar wind and the main source of the coronal heating, is characterized by the Poynting flux of the waves, which is also aligned with the magnetic field. Therefore, the plasma state in any point of the three-dimensional grid in the Low Solar Corona can be found by solving a set of one-dimensional equations for the magnetic field line ('thread'), which passes through this point and connects it to the chromosphere and to the global Solar Corona. In the present paper we describe an innovative computational technology based upon the use of the magnetic-field-line-threads to find the local solution. We present the development of the AWSoM code of the University of Michigan with the field-lines-threaded Low Solar Corona. In the transition region, where the essentially kinetic description of the electron energy fluxes is required, we solve the Fokker-Plank equation on the system of threads, to achieve the physically consistent description of chromosphere evaporation. The third application for the field-lines-treaded model is the Solar Energetic Particle (SEP) acceleration and transport. Being the natural extension of the Field-Line

  3. Measurement of the DC Stark shift for visible NeI lines and electric field distribution in the cathode sheath of an abnormal glow discharge

    NASA Astrophysics Data System (ADS)

    Ivanović, N. V.; Šišović, N. M.; Spasojević, Dj; Konjević, N.

    2017-03-01

    We present the results of an experimental study of the DC Stark shift for seven visible NeI lines in the plane cathode sheath region of an abnormal glow discharge operated in neon with a small admixture of hydrogen. The electric field (up to 13.4 kV cm‑1) in the cathode sheath region is measured from the π-polarized profile of the H alpha line of hydrogen using the Stark polarization spectroscopy technique. Within the realized range of the electric field, the NeI lines exhibit a quadratic Stark effect. The values of coefficients, correlating Stark shift and electric field strength, were determined, enabling their future use for unknown electric field strength measurements. Among the studied lines, so far only the Stark effect analysis of the NeI 511.367 nm line has been reported, in which case our results are in good agreement with the best fit formula proposed by Jäger and Windholz (1984 Phys. Scr. 29 344) for one out of three Stark components detected under our experimental conditions.

  4. Pinning in the flux-line-cutting regime of Bi 2Sr 2Ca 1Cu 2O 8 single crystals at high field

    NASA Astrophysics Data System (ADS)

    D'Anna, G.; André, M.-O.; Indenbom, M. V.; Benoit, W.

    1994-09-01

    Using a low-frequency torsion pendulum we show that in a Bi 2Sr 2Ca 1Cu 2O 8 single crystal the irreversibility line Birr( T) is frequency dependent down to 10 -5 Hz in the high-field regime. The activation energy has a logarithmic field dependence, U0( B)= U∗ 1n( B∗/ B). A microscopic model for flux-line-cutting and pancake collision yields quantitative expressions for U0 and for Birr( T)= B∗ exp(- T/T∗), which reproduce the experimental data very well.

  5. X-ray-induced apoptosis of BEL-7402 cell line enhanced by extremely low frequency electromagnetic field in vitro.

    PubMed

    Jian, Wen; Wei, Zhao; Zhiqiang, Cheng; Zheng, Fang

    2009-02-01

    This study was designed to test whether extremely low frequency electromagnetic field (ELF-EMF) could enhance the apoptosis-induction effect of X-ray radiotherapy on liver cancer cell line BEL-7402 in vitro. EMF exposure was performed inside an energized solenoid coil. X-ray irradiation was performed using a linear accelerator. Apoptosis rates of BEL-7402 cells were analyzed using Annexin V-Fit Apoptosis Detection kit. Apoptosis rates of EMF group and sham EMF group were compared when combined with X-ray irradiation. Our results suggested that the apoptosis rate of BEL-7402 cells exposed to low doses of X-ray irradiation could be significantly increased by EMF. More EMF exposures obtain significantly higher apoptosis rates than fewer EMF exposures when combined with 2 Gy X-ray irradiation. These findings suggested that ELF-EMF could augment the cell apoptosis effects of low doses of X-ray irradiation on BEL-7402 cells in a synergistic and cumulative way.

  6. Comparisons of Earthward Poynting flux and the kinetic energy flux of up-flowing transversely heated ions from the Polar spacecraft on cusp magnetic field lines

    NASA Astrophysics Data System (ADS)

    Tian, S.; Wygant, J. R.; Cattell, C. A.; Scudder, J. D.; Mozer, F.; Russell, C. T.

    2013-12-01

    This paper presents estimates of the Poynting flux flowing along magnetic field lines in the Earth's cusp region over altitudes from 0.8 Re to 7 Re using measurements during several passes from the Polar spacecraft. The Poynting flux is calculated from measurements of electric fields from the University of California, Berkeley double probe electric field instrument, and from magnetic field measurements from the U.C.L.A. fluxgate magnetometer. The estimates of Poynting flux are of special interest because the high altitude mapping of the cusp magnetic flux tubes may connect to newly reconnected field lines and the low altitude mapping of these field lines is the scene of powerful acceleration processes, most notably transverse heating and outflow of ions. The data show that the Poynting flux is predominantly downward over the frequency range from 1 mHz to 1 Hz . This frequency range includes the Poynting flux due to steady state convection and field-aligned current systems, Alfven waves, and kinetic Alfven waves. Measurement of transversely heated ions over the energy ranges from 10 eV to several keV and their associated ion kinetic energy flux are presented from the University of Iowa Hydra instrument and compared to the values of the downward Poynting flux. Generally the downward Poynting flux exceeds the upward kinetic energy flux of the ions.

  7. Stress Wave Interaction Between Two Adjacent Blast Holes

    NASA Astrophysics Data System (ADS)

    Yi, Changping; Johansson, Daniel; Nyberg, Ulf; Beyglou, Ali

    2016-05-01

    Rock fragmentation by blasting is determined by the level and state of stress in the rock mass subjected to blasting. With the application of electronic detonators, some researchers stated that it is possible to achieve improved fragmentation through stress wave superposition with very short delay times. This hypothesis was studied through theoretical analysis in the paper. First, the stress in rock mass induced by a single-hole shot was analyzed with the assumptions of infinite velocity of detonation and infinite charge length. Based on the stress analysis of a single-hole shot, the stress history and tensile stress distribution between two adjacent holes were presented for cases of simultaneous initiation and 1 ms delayed initiation via stress superposition. The results indicated that the stress wave interaction is local around the collision point. Then, the tensile stress distribution at the extended line of two adjacent blast holes was analyzed for a case of 2 ms delay. The analytical results showed that the tensile stress on the extended line increases due to the stress wave superposition under the assumption that the influence of neighboring blast hole on the stress wave propagation can be neglected. However, the numerical results indicated that this assumption is unreasonable and yields contrary results. The feasibility of improving fragmentation via stress wave interaction with precise initiation was also discussed. The analysis in this paper does not support that the interaction of stress waves improves the fragmentation.

  8. Fouling assemblages on offshore wind power plants and adjacent substrata

    NASA Astrophysics Data System (ADS)

    Wilhelmsson, Dan; Malm, Torleif

    2008-09-01

    A significant expansion of offshore wind power is expected in the near future, with thousands of turbines in coastal waters, and various aspects of how this may influence the coastal ecology including disturbance effects from noise, shadows, electromagnetic fields, and changed hydrological conditions are accordingly of concern. Further, wind power plants constitute habitats for a number of organisms, and may locally alter assemblage composition and biomass of invertebrates, algae and fish. In this study, fouling assemblages on offshore wind turbines were compared to adjacent hard substrate. Influences of the structures on the seabed were also investigated. The turbines differed significantly from adjacent boulders in terms of assemblage composition of epibiota and motile invertebrates. Species number and Shannon-Wiener diversity were, also, significantly lower on the wind power plants. It was also indicated that the turbines might have affected assemblages of invertebrates and algae on adjacent boulders. Off shore wind power plant offer atypical substrates for fouling assemblages in terms of orientation, depth range, structure, and surface texture. Some potential ecological implications of the addition of these non-natural habitats for coastal ecology are discussed.

  9. Line shapes and time dynamics of the Förster resonances between two Rydberg atoms in a time-varying electric field

    NASA Astrophysics Data System (ADS)

    Yakshina, E. A.; Tretyakov, D. B.; Beterov, I. I.; Entin, V. M.; Andreeva, C.; Cinins, A.; Markovski, A.; Iftikhar, Z.; Ekers, A.; Ryabtsev, I. I.

    2016-10-01

    The observation of the Stark-tuned Förster resonances between Rydberg atoms excited by narrowband cw laser radiation requires usage of a Stark-switching technique in order to excite the atoms first in a fixed electric field and then to induce the interactions in a varied electric field, which is scanned across the Förster resonance. In our experiments with a few cold Rb Rydberg atoms, we have found that the transients at the edges of the electric pulses strongly affect the line shapes of the Förster resonances, since the population transfer at the resonances occurs on a time scale of ˜100 ns, which is comparable with the duration of the transients. For example, a short-term ringing at a certain frequency causes additional radio-frequency-assisted Förster resonances, while nonsharp edges lead to asymmetry. The intentional application of the radio-frequency field induces transitions between collective states, whose line shape depends on the interaction strengths and time. Spatial averaging over the atom positions in a single interaction volume yields a cusped line shape of the Förster resonance. We present a detailed experimental and theoretical analysis of the line shape and time dynamics of the Stark-tuned Förster resonances Rb (n P3 /2) +Rb (n P3 /2) →Rb (n S1 /2) +Rb ([n +1 ] S1 /2) for two Rb Rydberg atoms interacting in a time-varying electric field.

  10. Pulsed electromagnetic field affects intrinsic and endoplasmatic reticulum apoptosis induction pathways in MonoMac6 cell line culture.

    PubMed

    Kaszuba-Zwoinska, J; Chorobik, P; Juszczak, K; Zaraska, W; Thor, P J

    2012-10-01

    Current studies were aimed to elucidate influence of pulsed electromagnetic field stimulation on cell viability and apoptosis induction pathways. For the experimental model we have chosen monocytic cell line MonoMac6 and several apoptosis inducers with different mechanism of death induction like puromycin, colchicine, cyclophosphamide, minocycline and hydrogen peroxide. MonoMac6 cell line was grown at density 1x10(5) cells/well in 96-well culture plates. To induce cell death cell cultures were treated with different apoptosis inducers like puromycin, colchicine, cyclophosphamide, minocycline, hydrogen peroxide and at the same time with pulsed electromagnetic field 50 Hz, 45±5 mT (PEMF) for 4 hour per each stimulation, three times, in 24 hours intervals. Afterwards, cells were harvested for flow cytometry analysis of cell viability measured by annexin V-APC labeled and propidium iodide staining. Expression of apoptosis related genes was evaluated by semi quantitative reverse transcription (RT)-PCR assay. NuPAGE Novex Western blot analysis was carried out for apoptosis inducing factor (AIF) abundance in cytosolic and nuclear extracts of MonoMac6 cells. Puromycin, colchicine and minocycline activated cells and simultaneously treated with PEMF have shown out diminished percentage of annexinV positive (AnV+) cells comparing to controls without PEMF stimulation. MonaMac6 cells puromycin/colchicyne and PEMF treated were to a higher extent double stained (AnV+,PI+), which means increased late apoptotic as well as necrotic (PI+) cells, than non-stimulated controls. On the other hand, minocycline activated cells prior to PEMF treatment showed diminished amount of apoptotic and necrotic (annexin V, annexin V and propidium iodide, propidium iodide positive staining) cells. The opposite effect of PEMF on the percentage of annexin V positively stained cells has been achieved after treatment of MonoMac6 culture with cyclophoshamide and hydrogen peroxide. PEMF enhanced early

  11. An algorithm for approximating the L * invariant coordinate from the real-time tracing of one magnetic field line between mirror points

    NASA Astrophysics Data System (ADS)

    Lejosne, Solène

    2014-08-01

    The L * invariant coordinate depends on the global electromagnetic field topology at a given instance, and the standard method for its determination requires a computationally expensive drift contour tracing. This fact makes L * a cumbersome parameter to handle. In this paper, we provide new insights on the L * parameter, and we introduce an algorithm for an L * approximation that only requires the real-time tracing of one magnetic field line between mirrors points. This approximation is based on the description of the variation of the magnetic field mirror intensity after an adiabatic dipolarization, i.e., after the nondipolar components of a magnetic field have been turned off with a characteristic time very long in comparison with the particles' drift periods. The corresponding magnetic field topological variations are deduced, assuming that the field line foot points remain rooted in the Earth's surface, and the drift average operator is replaced with a computationally cheaper circular average operator. The algorithm results in a relative difference of a maximum of 12% between the approximate L * and the output obtained using the International Radiation Belt Environment Modeling library, in the case of the Tsyganenko 89 model for the external magnetic field (T89). This margin of error is similar to the margin of error due to small deviations between different magnetic field models at geostationary orbit. This approximate L * algorithm represents therefore a reasonable compromise between computational speed and accuracy of particular interest for real-time space weather forecast purposes.

  12. Interaction of Cracks Between Two Adjacent Indents in Glass

    NASA Technical Reports Server (NTRS)

    Choi, S. R.; Salem, J. A.

    1993-01-01

    Experimental observations of the interaction behavior of cracks between two adjacent indents were made using an indentation technique in soda-lime glass. It was specifically demonstrated how one indent crack initiates and propagates in the vicinity of another indent crack. Several types of crack interactions were examined by changing the orientation and distance of one indent relative to the other. It was found that the residual stress field produced by elastic/plastic indentation has a significant influence on controlling the mode of crack interaction. The interaction of an indent crack with a free surface was also investigated for glass and ceramic specimens.

  13. Empires and percolation: stochastic merging of adjacent regions

    NASA Astrophysics Data System (ADS)

    Aldous, D. J.; Ong, J. R.; Zhou, W.

    2010-01-01

    We introduce a stochastic model in which adjacent planar regions A, B merge stochastically at some rate λ(A, B) and observe analogies with the well-studied topics of mean-field coagulation and of bond percolation. Do infinite regions appear in finite time? We give a simple condition on λ for this hegemony property to hold, and another simple condition for it to not hold, but there is a large gap between these conditions, which includes the case λ(A, B) ≡ 1. For this case, a non-rigorous analytic argument and simulations suggest hegemony.

  14. Laboratory toxicity and benthic invertebrate field colonization of Upper Columbia River sediments: Finding adverse effects using multiple lines of evidence

    USGS Publications Warehouse

    Fairchild, J.F.; Kemble, N.E.; Allert, A.L.; Brumbaugh, W.G.; Ingersoll, C.G.; Dowling, B.; Gruenenfelder, C.; Roland, J.L.

    2012-01-01

    studies in an experimental pond (8-week duration) indicated that two of the most metal-contaminated UCR sediments (dominated by high levels of sand-sized slag particles) exhibited decreased invertebrate colonization compared with sand-based reference sediments. Field-exposed SIR-300 resin samples also exhibited decreased invertebrate colonization numbers compared with reference materials, which may indicate behavioral avoidance of this material under field conditions. Multiple lines of evidence (analytical chemistry, laboratory toxicity, and field colonization results), along with findings from previous studies, indicate that high metal concentrations associated with slag-enriched sediments in the UCR are likely to adversely impact the growth and survival of native benthic invertebrate communities. Additional laboratory toxicity testing, refinement of the applications of sediment benchmarks for metal toxicity, and in situ benthic invertebrate studies will assist in better defining the spatial extent, temporal variations, and ecological impacts of metal-contaminated sediments in the UCR system.

  15. Reconnection of vorticity lines and magnetic lines

    NASA Technical Reports Server (NTRS)

    Greene, John M.

    1993-01-01

    Magnetic field and fluid vorticity share many features. First, as divergence-free vector fields they are conveniently visualized in terms of their field lines, curves that are everywhere tangent to the field. The lines indicate direction and their density indicates field strength. The question arises of the extent to which the evolution of the fields can be treated in terms of the evolution of their field lines. Newcomb (1958) derived the general conditions on the evolution of vector fields that permit the identification of field lines from one instant to the next. The equations of evolution of the vorticity field and the magnetic field fall within Newcomb's analysis. The dynamics of the flows differ between these two systems, so that geometrically similar phenomena happen in different ways in the two systems. In this paper the geometrical similarities are emphasized. Reconnection will be defined here as evolution in which it is not possible to preserve the global identification of some field lines. There is a close relation between reconnection and the topology of the vector field lines. Nontrivial topology occurs where the field has null points or there are field lines that are closed loops.

  16. Adjacent Segment Pathology after Anterior Cervical Fusion

    PubMed Central

    Chung, Jae Yoon; Park, Jong-Beom; Seo, Hyoung-Yeon

    2016-01-01

    Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion. PMID:27340541

  17. Calibrating R-LINE model results with observational data to develop annual mobile source air pollutant fields at fine spatial resolution: Application in Atlanta

    NASA Astrophysics Data System (ADS)

    Zhai, Xinxin; Russell, Armistead G.; Sampath, Poornima; Mulholland, James A.; Kim, Byeong-Uk; Kim, Yunhee; D'Onofrio, David

    2016-12-01

    The Research LINE-source (R-LINE) dispersion model for near-surface releases is a dispersion model developed to estimate the impacts of line sources, such as automobiles, on primary air pollutant levels. In a multiyear application in Atlanta, R-LINE simulations overestimated concentrations and spatial gradients compared to measurements. In this study we present a computationally efficient procedure for calculating annual average spatial fields and develop an approach for calibrating R-LINE concentrations with observational data. Simulated hourly concentrations of PM2.5, CO and NOx from mobile sources at 250 m resolution in the 20-county Atlanta area based on average diurnal emission profiles and meteorological categories were used to estimate annual averages. Compared to mobile source PM2.5 impacts estimated by chemical mass balance with gas constraints (CMB-GC), a source apportionment model based on PM2.5 speciation measurements, R-LINE estimates of traffic-generated PM2.5 impacts were found to be higher by a factor of 1.8 on average across all sites. Compared to observations of daily 1 h maximum CO and NOx, R-LINE estimates were higher by factors of 1.3 and 4.2 on average, respectively. Annual averages estimated by R-LINE were calibrated by regression with observations from 2002 to 2011 at multiple sites for daily 1 h maximum CO and NOx and with measurement-based mobile source impacts estimated by CMB-GC for PM2.5. The calibration reduced normalized mean bias (NMB) from 29% to 0.3% for PM2.5, from 22% to -1% for CO, and from 303% to 49% for NOx. Cross-validation analysis (withholding sites one at a time) leads to NMB of 13%, 1%, and 69% for PM2.5, CO, and NOx, respectively. The observation-calibrated R-LINE annual average spatial fields were compared with pollutant fields from observation-blended, 12 km resolution Community Multi-scale Air Quality (CMAQ) model fields for CO and NOx, with Pearson correlation R2 values of 0.55 for CO and 0.54 for NOx found. The

  18. Space-charge compensation measurements in electron cyclotron resonance ion source low energy beam transport lines with a retarding field analyzer

    SciTech Connect

    Winklehner, D.; Leitner, D. Cole, D.; Machicoane, G.; Tobos, L.

    2014-02-15

    In this paper we describe the first systematic measurement of beam neutralization (space charge compensation) in the ECR low energy transport line with a retarding field analyzer, which can be used to measure the potential of the beam. Expected trends for the space charge compensation levels such as increase with residual gas pressure, beam current, and beam density could be observed. However, the overall levels of neutralization are consistently low (<60%). The results and the processes involved for neutralizing ion beams are discussed for conditions typical for ECR injector beam lines. The results are compared to a simple theoretical beam plasma model as well as simulations.

  19. Printed circuit dispersive transmission line

    DOEpatents

    Ikezi, Hiroyuki; Lin-Liu, Yuh-Ren; DeGrassie, John S.

    1991-01-01

    A printed circuit dispersive transmission line structure is disclosed comprising an insulator, a ground plane formed on one surface of the insulator, a first transmission line formed on a second surface of the insulator, and a second transmission line also formed on the second surface of the insulator and of longer length than the first transmission line and periodically intersecting the first transmission line. In a preferred embodiment, the transmission line structure exhibits highly dispersive characteristics by designing the length of one of the transmission line between two adjacent periodic intersections to be longer than the other.

  20. Printed circuit dispersive transmission line

    DOEpatents

    Ikezi, H.; Lin-Liu, Y.R.; DeGrassie, J.S.

    1991-08-27

    A printed circuit dispersive transmission line structure is disclosed comprising an insulator, a ground plane formed on one surface of the insulator, a first transmission line formed on a second surface of the insulator, and a second transmission line also formed on the second surface of the insulator and of longer length than the first transmission line and periodically intersecting the first transmission line. In a preferred embodiment, the transmission line structure exhibits highly dispersive characteristics by designing the length of one of the transmission line between two adjacent periodic intersections to be longer than the other. 5 figures.

  1. New species of Amanita from the eastern Himalaya and adjacent regions.

    PubMed

    Yang, Zhu L; Weiß, M; Oberwinkler, F

    2004-01-01

    Four new species of Amanita, Amanita-ceae (Agaricales) are described from the eastern Himalaya and adjacent regions of southwestern China. Amanita altipes and A. parvipantherina are members of section Amanita, while A. orientifulva and A. liquii are representatives of section Vaginatae. They are compared with similar species and illustrated with line drawings.

  2. 33 CFR 110.140 - Buzzards Bay, Nantucket Sound, and adjacent waters, Mass.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Buzzards Bay, Nantucket Sound..., Nantucket Sound, and adjacent waters, Mass. (a) New Bedford Outer Harbor—(1) Anchorage A. West of Sconticut... Sounds—(1) Anchorage E. South of a line beginning at a point bearing 180° about 3.25 miles from...

  3. 33 CFR 110.140 - Buzzards Bay, Nantucket Sound, and adjacent waters, Mass.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Buzzards Bay, Nantucket Sound..., Nantucket Sound, and adjacent waters, Mass. (a) New Bedford Outer Harbor—(1) Anchorage A. West of Sconticut... Sounds—(1) Anchorage E. South of a line beginning at a point bearing 180° about 3.25 miles from...

  4. 33 CFR 110.140 - Buzzards Bay, Nantucket Sound, and adjacent waters, Mass.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Buzzards Bay, Nantucket Sound..., Nantucket Sound, and adjacent waters, Mass. (a) New Bedford Outer Harbor—(1) Anchorage A. West of Sconticut... Sounds—(1) Anchorage E. South of a line beginning at a point bearing 180° about 3.25 miles from...

  5. 33 CFR 110.140 - Buzzards Bay, Nantucket Sound, and adjacent waters, Mass.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Buzzards Bay, Nantucket Sound..., Nantucket Sound, and adjacent waters, Mass. (a) New Bedford Outer Harbor—(1) Anchorage A. West of Sconticut... Sounds—(1) Anchorage E. South of a line beginning at a point bearing 180° about 3.25 miles from...

  6. Diagnosis of magnetic and electric fields of chromospheric jets through spectropolarimetric observations of H I Paschen lines

    SciTech Connect

    Anan, T.; Ichimoto, K.; Casini, R. E-mail: ichimoto@kwasan.kyoto-u.ac.jp

    2014-05-10

    Magnetic fields govern the plasma dynamics in the outer layers of the solar atmosphere, and electric fields acting on neutral atoms that move across the magnetic field enable us to study the dynamical coupling between neutrals and ions in the plasma. In order to measure the magnetic and electric fields of chromospheric jets, the full Stokes spectra of the Paschen series of neutral hydrogen in a surge and in some active region jets that took place at the solar limb were observed on 2012 May 5, using the spectropolarimeter of the Domeless Solar Telescope at Hida observatory, Japan. First, we inverted the Stokes spectra taking into account only the effect of magnetic fields on the energy structure and polarization of the hydrogen levels. Having found no definitive evidence of the effects of electric fields in the observed Stokes profiles, we then estimated an upper bound for these fields by calculating the polarization degree under the magnetic field configuration derived in the first step, with the additional presence of a perpendicular (Lorentz type) electric field of varying strength. The inferred direction of the magnetic field on the plane of the sky approximately aligns to the active region jets and the surge, with magnetic field strengths in the range 10 G < B < 640 G for the surge. Using magnetic field strengths of 70, 200, and 600 G, we obtained upper limits for possible electric fields of 0.04, 0.3, and 0.8 V cm{sup –1}, respectively. This upper bound is conservative, since in our modeling we neglected the possible contribution of collisional depolarization. Because the velocity of neutral atoms of hydrogen moving across the magnetic field derived from these upper limits of the Lorentz electric field is far below the bulk velocity of the plasma perpendicular to the magnetic field as measured by the Doppler shift, we conclude that the neutral atoms must be highly frozen to the magnetic field in the surge.

  7. Diagnosis of Magnetic and Electric Fields of Chromospheric Jets through Spectropolarimetric Observations of H I Paschen Lines

    NASA Astrophysics Data System (ADS)

    Anan, T.; Casini, R.; Ichimoto, K.

    2014-05-01

    Magnetic fields govern the plasma dynamics in the outer layers of the solar atmosphere, and electric fields acting on neutral atoms that move across the magnetic field enable us to study the dynamical coupling between neutrals and ions in the plasma. In order to measure the magnetic and electric fields of chromospheric jets, the full Stokes spectra of the Paschen series of neutral hydrogen in a surge and in some active region jets that took place at the solar limb were observed on 2012 May 5, using the spectropolarimeter of the Domeless Solar Telescope at Hida observatory, Japan. First, we inverted the Stokes spectra taking into account only the effect of magnetic fields on the energy structure and polarization of the hydrogen levels. Having found no definitive evidence of the effects of electric fields in the observed Stokes profiles, we then estimated an upper bound for these fields by calculating the polarization degree under the magnetic field configuration derived in the first step, with the additional presence of a perpendicular (Lorentz type) electric field of varying strength. The inferred direction of the magnetic field on the plane of the sky approximately aligns to the active region jets and the surge, with magnetic field strengths in the range 10 G < B < 640 G for the surge. Using magnetic field strengths of 70, 200, and 600 G, we obtained upper limits for possible electric fields of 0.04, 0.3, and 0.8 V cm-1, respectively. This upper bound is conservative, since in our modeling we neglected the possible contribution of collisional depolarization. Because the velocity of neutral atoms of hydrogen moving across the magnetic field derived from these upper limits of the Lorentz electric field is far below the bulk velocity of the plasma perpendicular to the magnetic field as measured by the Doppler shift, we conclude that the neutral atoms must be highly frozen to the magnetic field in the surge.

  8. Measuring 20-100 T B-fields using Zeeman splitting of sodium emission lines on a 500 kA pulsed power machine

    NASA Astrophysics Data System (ADS)

    Banasek, J. T.; Engelbrecht, J. T.; Pikuz, S. A.; Shelkovenko, T. A.; Hammer, D. A.

    2016-11-01

    We have shown that Zeeman splitting of the sodium (Na) D-lines at 5890 and 5896 Å can be used to measure the magnetic field (B-field) produced in high current pulsed power experiments. We have measured the B-field next to a return current conductor in a hybrid X-pinch experiment near a peak current of about 500 kA. Na is deposited on the conductor and then is desorbed and excited by radiation from the hybrid X-pinch. The D-line emission spectrum implies B-fields of about 20 T with a return current post of 4 mm diameter or up to 120 T with a return current wire of 0.455 mm diameter. These measurements were consistent or lower than the expected B-field, thereby showing that basic Zeeman splitting can be used to measure the B-field in a pulsed-power-driven high-energy-density (HED) plasma experiment. We hope to extend these measurement techniques using suitable ionized species to measurements within HED plasmas.

  9. CAFE — A New On-Line Resource for Planning Scientific Field Investigations in Planetary Analogue Environments

    NASA Astrophysics Data System (ADS)

    Preston, L. J.; Barber, S. J.; Grady, M. M.

    2012-03-01

    The Concepts for Activities in the Field for Exploration (CAFE) project is creating a complete catalogue of terrestrial analogue environments that are appropriate for testing human space exploration-related scientific field activities.

  10. The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Implications for Spectral Line Intensity Mapping at Millimeter Wavelengths and CMB Spectral Distortions

    NASA Astrophysics Data System (ADS)

    Carilli, C. L.; Chluba, J.; Decarli, R.; Walter, F.; Aravena, M.; Wagg, J.; Popping, G.; Cortes, P.; Hodge, J.; Weiss, A.; Bertoldi, F.; Riechers, D.

    2016-12-01

    We present direct estimates of the mean sky brightness temperature in observing bands around 99 and 242 GHz due to line emission from distant galaxies. These values are calculated from the summed line emission observed in a blind, deep survey for spectral line emission from high redshift galaxies using ALMA (the ALMA spectral deep field observations “ASPECS” survey). In the 99 GHz band, the mean brightness will be dominated by rotational transitions of CO from intermediate and high redshift galaxies. In the 242 GHz band, the emission could be a combination of higher order CO lines, and possibly [C ii] 158 μm line emission from very high redshift galaxies (z ˜ 6-7). The mean line surface brightness is a quantity that is relevant to measurements of spectral distortions of the cosmic microwave background, and as a potential tool for studying large-scale structures in the early universe using intensity mapping. While the cosmic volume and the number of detections are admittedly small, this pilot survey provides a direct measure of the mean line surface brightness, independent of conversion factors, excitation, or other galaxy formation model assumptions. The mean surface brightness in the 99 GHZ band is: T B = 0.94 ± 0.09 μK. In the 242 GHz band, the mean brightness is: T B = 0.55 ± 0.033 μK. These should be interpreted as lower limits on the average sky signal, since we only include lines detected individually in the blind survey, while in a low resolution intensity mapping experiment, there will also be the summed contribution from lower luminosity galaxies that cannot be detected individually in the current blind survey.

  11. Isophotes of a field in the Cygnus loop photographed in the (O III) and (N II)+H. cap alpha. lines

    SciTech Connect

    Sitnik, T.G.; Toropova, M.S.

    1982-11-01

    From interference-filter image-tube photographs of a 9' field in the western part of the Cygnus Loop supernova remnant, taken in the lambda5007 (O III) and lambdalambda 6584, 6563 (N II) + H..cap alpha.. lines, sets of isophotes are derived by an equidensitometry technique based on the Sabattier effect. The emission regions in these lines exhibit a relative displacement, interpreted as evidence for radiative cooling of the gas behind the shock generated in the supernova outburst. An explanation is offered for the differing morphology of the nebular filaments in the (O III) and (N II) + H..cap alpha.. lines. The anomalously high I/sub Otsi/II/I/sub H/..beta.. intensity ratio may reflect a spatial separation of the corresponding emission zones.

  12. Inhibition of cellular proliferation and enhancement of hydrogen peroxide production in fibrosarcoma cell line by weak radio frequency magnetic fields.

    PubMed

    Castello, Pablo R; Hill, Iain; Sivo, Frank; Portelli, Lucas; Barnes, Frank; Usselman, Robert; Martino, Carlos F

    2014-12-01

    This study presents experimental data for the effects of weak radio frequency (RF) magnetic fields on hydrogen peroxide (H2O2) production and cellular growth rates of fibrosarcoma HT1080 cells in vitro. Cells were exposed either to 45 µT static magnetic fields (SMFs)-oriented vertical to the plane of growth or to SMFs combined with weak 5 and 10 MHz RF magnetic fields of 10 µTRMS intensity perpendicular to the static field. Cell numbers were reduced up to 30% on Day 2 for the cells exposed to the combination of SMF and a 10 MHz RF magnetic field compared with the SMF control cells. In addition, cells exposed to 10 MHz RF magnetic fields for 8 h increased H2O2 production by 55%. The results demonstrate an overall magnetic field-induced biological effect that shows elevated H2O2 levels with accompanying decrease in cellular growth rates.

  13. Probability of acoustic transmitter detections by receiver lines in Lake Huron: results of multi-year field tests and simulations

    USGS Publications Warehouse

    Hayden, Todd A.; Holbrook, Christopher M.; Binder, Thomas; Dettmers, John M.; Cooke, Steven J.; Vandergoot, Christopher S.; Krueger, Charles C.

    2016-01-01

    BackgroundAdvances in acoustic telemetry technology have led to an improved understanding of the spatial ecology of many freshwater and marine fish species. Understanding the performance of acoustic receivers is necessary to distinguish between tagged fish that may have been present but not detected and from those fish that were absent from the area. In this study, two stationary acoustic transmitters were deployed 250 m apart within each of four acoustic receiver lines each containing at least 10 receivers (i.e., eight acoustic transmitters) located in Saginaw Bay and central Lake Huron for nearly 2 years to determine whether the probability of detecting an acoustic transmission varied as a function of time (i.e., season), location, and distance between acoustic transmitter and receiver. Distances between acoustic transmitters and receivers ranged from 200 m to >10 km in each line. The daily observed probability of detecting an acoustic transmission was used in simulation models to estimate the probability of detecting a moving acoustic transmitter on a line of receivers.ResultsThe probability of detecting an acoustic transmitter on a receiver 1000 m away differed by month for different receiver lines in Lake Huron and Saginaw Bay but was similar for paired acoustic transmitters deployed 250 m apart within the same line. Mean probability of detecting an acoustic transmitter at 1000 m calculated over the study period varied among acoustic transmitters 250 m apart within a line and differed among receiver lines in Lake Huron and Saginaw Bay. The simulated probability of detecting a moving acoustic transmitter on a receiver line was characterized by short periods of time with decreased detection. Although increased receiver spacing and higher fish movement rates decreased simulated detection probability, the location of the simulated receiver line in Lake Huron had the strongest effect on simulated detection probability.ConclusionsPerformance of receiver

  14. Second solar spectrum of the Sr I 4607 Å line: depth probing of the turbulent magnetic field strength in a quiet region

    NASA Astrophysics Data System (ADS)

    Derouich, M.; Bommier, V.; Malherbe, J. M.; Landi Degl'Innocenti, E.

    2006-10-01

    Aims.This paper is devoted to an interpretation of Quiet-Sun, spatially-resolved spectropolarimetric observations of the Hanle effect in terms of turbulent weak magnetic field determination. Methods: . Observations: the slit was positioned perpendicular to the limb, and the spatial resolution along the slit was 1 arcsec, leading to a depth probing along 132 different limb distances. The new polarimeter of the Pic-du-Midi Turret Dome was used on May 14, 2004 to observe a quiet region at the East limb equator in the resonance line of neutral Strontium at 4607 Å. Results: . For each limb distance, we properly adjusted the theoretical intensity profile obtained by applying a zero-field model to the observed one. Micro- and macroturbulent velocities were thus derived (average values v{micro}=1.77 km s-1 and v{macro}=1.95 km s-1). The magnetic field was determined in a second step by interpreting the Hanle effect on the line center linear polarization degree. The depolarizing collisions with neutral hydrogen were taken fully into account through a semi-classical calculation of their rates. An average value of B=38 Gauss was thus derived. Finally, error bars on the magnetic field values were evaluated from a) the polarimetric inaccuracy, b) the limb distance determination inaccuracy, and c) the uncertainty on our theoretical collisional depolarizing rates that we evaluated. This combination leads to 10-20% as total relative error on the magnetic field determination by the Hanle effect method. Since the inaccuracy due to the model itself was hard to properly evaluate, it was ignored. An uncertainty of ±60 km on the line formation depth was, however, derived from the contribution functions. The magnetic field is found to increase slowly with height in the height range 220-300 km above τ5000=1 and then decrease in the height range 300-370 km.

  15. Effects of vortex line shape on critical current density in high Tc superconducting film with nano-rod pinning centers under applied magnetic field of various orientations

    NASA Astrophysics Data System (ADS)

    Kwak, K.; Rhee, J.; Lee, W.; Lee, H.; Youm, D.; Yoo, J.

    2013-03-01

    We measured magneto-optical images (MOIs) on a coated conductor comprised of (Gd,Y)1Ba2Cu3O7-δ-BaZrO3 film under applied magnetic field of various orientations. MOIs showed systematic changes of asymmetric distribution of magnetic flux density and critical current density. TEM measurements showed that nano-rod pinning centers (RPCs) tilt by ∼13° from the c-axis. We were able to explain the results of MOI measurements using a simple model calculation about vortex line shapes, which change according to the magnitude and the orientation of applied magnetic field. In this model the critical current density, which is due to the vortex pinning, is determined by the geometrical relationship of the curved vortex lines and the tilted RPCs.

  16. The formation of interstellar molecular lines in a turbulent velocity field with finite correlation length III. Spherical clouds in hydrostatic equilibrium.

    NASA Astrophysics Data System (ADS)

    Piehler, G.; Kegel, W. H.

    1995-05-01

    We investigated the formation of interstellar molecular lines in a turbulent velocity field with finite correlation length, extending previous work (Albrecht & Kegel 1987; Kegel et al. 1992) to isothermal spheres in hydrostatic equilibrium as cloud models with σ>>v_ therm _. For this we use the transformed generalized radiative transfer equation (Kegel et al. 1992). We concentrate our calculations on the CO-molecule with up to 12 energy levels. We give numerical results for models with T_kin_=50K, σ=3.9km/sec (σ/v_ therm _=22), and different values of the central H_2_ density and different values of the correlation length. As our results show, accounting for a velocity field with a finite correlation length affects the line profiles, the center-to-limb variation, and the intensity ratios. We find that the higher transitions are more strongly affected than the J=1-0 transition.

  17. Method for making a superconducting gradiometer having a three-dimensional structure and associated connecting lines for a device for measuring weak magnetic fields

    SciTech Connect

    Daalmans, G.M.

    1987-09-22

    This patent describes a method for manufacturing a gradiometer having a three-dimensional structure for a device for the single-or multichannel measurement of magnetic fields with field intensities down to less than 10/sup -10/T and in particular, below 10/sup -12/T. At least one superconducting gradiometer coil of predetermined dimensions is arranged a support body and connected by means of superconducting connecting lines and a coupling coil to a superconducting quantum interference element (SQUID) in a magnetically coupling manner. The gradiometer coil and at least the connecting lines associated with the coil are applied as thick or thin films together and simultaneously to a common three-dimensional support body in which at least one coating operation is preceded for the position-wise fixation of the corresponding conductor runs by a lithographic process.

  18. Multi-fields direct design approach in 3D: calculating a two-surface freeform lens with an entrance pupil for line imaging systems.

    PubMed

    Nie, Yunfeng; Thienpont, Hugo; Duerr, Fabian

    2015-12-28

    Including an entrance pupil in optical systems provides clear benefits for balancing the overall performance of freeform and/or rotationally symmetric imaging systems. Current existing direct design methods that are based on perfect imaging of few discrete ray bundles are not well suited for wide field of view systems. In this paper, a three-dimensional multi-fields direct design approach is proposed to balance the full field imaging performance of a two-surface freeform lens. The optical path lengths and image points of numerous fields are calculated during the procedures, wherefore very few initial parameters are needed in advance. Design examples of a barcode scanner lens as well as a line imaging objective are introduced to demonstrate the effectiveness of this method.

  19. Environmental magnetic fields inhibit the antiproliferative action of tamoxifen and melatonin in a human breast cancer cell line.

    PubMed

    Harland, J D; Liburdy, R P

    1997-01-01

    We have previously reported that environmental-level magnetic fields (1.2 microT [12 milligauss], 60 Hz) block the growth inhibition of the hormone melatonin (10(-9) M) on MCF-7 human breast cancer cells in vitro. We now report that the same 1.2 microT, 60 Hz magnetic fields significantly block the growth inhibitory action of pharmacological levels of tamoxifen (10(-7) M). In biophysical studies we have taken advantage of Faraday's Law of Current Induction and tested whether the 1.2 microT magnetic field or the associated induced electric field is responsible for this field effect on melatonin and tamoxifen. We observe that the magnetic field component is associated with the field blocking effect on melatonin and tamoxifen function. To our knowledge the tamoxifen studies represent the first experimental evidence for an environmental-level magnetic field modification of drug interaction with human breast cancer cells. Together, these findings provide support to the theory that environmental-level magnetic fields can act to modify the action of a drug or hormone on regulation of cell proliferation. Melatonin and tamoxifen may act through different biological pathways to down-regulate cell growth, and further studies are required to identify a specific biological site of interaction for the 1.2 microT magnetic field.

  20. Magnetic field sensing with an in-line Fabry-Perot interferometer based on capillary optical fiber and Terfenol-D