SwePub
Tyck till om SwePub Sök här!
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Nanayakkara N) srt2:(2018)"

Sökning: WFRF:(Nanayakkara N) > (2018)

  • Resultat 1-2 av 2
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Chandimal, A. P. L., et al. (författare)
  • Impedance Behavior of Earth Enhancing Compound Under Lightning Transient Conditions
  • 2018
  • Ingår i: 2018 34th international conference on lightning protection (ICLP 2018). - New York : IEEE. - 9781538666357
  • Konferensbidrag (refereegranskat)abstract
    • This study was aimed at finding the performance of commercially available earth enhancing compound (EEC) under lightning conditions. Further to that, this is an extension of a previous study conducted by the same authors referring to the same EEC. The selected material seems to perform impressively under lightning conditions passing considerably large current values. The prepared EEC mixture and the setup was tested under dry conditions and exhibited low dynamic impedance characteristics for lightning impulse voltages. Ten-stage Marx-generator was used for the experiment, and due to high conductive nature of the material, HV supply between the sample was unable to increase more than few kV. Thus the 12 cm gap inside the material was complemented with an external air gap of 90 cm. The study was a comparison between "air-gap breakdown" and "air-gap plus material-gap breakdown". The results confirmed a low impedance characteristic for the selected EEC and suggested a very low electric field inside the material gap. An approximate value for the impedance of the test setup was calculated from the collected data. A time window was selected during the steady current discharge appeared just after the point of current peak and the impedance curves for both experiments were compared at a previously defined point at the time axis. The impedance value for EEC setup was estimated to be in the region of 1 - 2 Omega.
  •  
2.
  • Wisotzki, L., et al. (författare)
  • Nearly all the sky is covered by Lyman-alpha emission around high-redshift galaxies
  • 2018
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 562:7726, s. 229-232
  • Tidskriftsartikel (refereegranskat)abstract
    • Galaxies are surrounded by large reservoirs of gas, mostly hydrogen, that are fed by inflows from the intergalactic medium and by outflows from galactic winds. Absorption-line measurements along the lines of sight to bright and rare background quasars indicate that this circumgalactic medium extends far beyond the starlight seen in galaxies, but very little is known about its spatial distribution. The Lyman-alpha transition of atomic hydrogen at a wavelength of 121.6 nanometres is an important tracer of warm (about 104 kelvin) gas in and around galaxies, especially at cosmological redshifts greater than about 1.6 at which the spectral line becomes observable from the ground. Tracing cosmic hydrogen through its Lyman-a emission has been a long-standing goal of observational astrophysics(1-3), but the extremely low surface brightness of the spatially extended emission is a formidable obstacle. A new window into circumgalactic environments was recently opened by the discovery of ubiquitous extended Lyman-alpha emission from hydrogen around high-redshift galaxies(4,5). Such measurements were previously limited to especially favourable systems(6-8) or to the use of massive statistical averaging(9,10) because of the faintness of this emission. Here we report observations of low-surface-brightness Lyman-alpha emission surrounding faint galaxies at redshifts between 3 and 6. We find that the projected sky coverage approaches 100 per cent. The corresponding rate of incidence (the mean number of Lyman-alpha emitters penetrated by any arbitrary line of sight) is well above unity and similar to the incidence rate of high-column-density absorbers frequently detected in the spectra of distant quasars(11-14). This similarity suggests that most circumgalactic atomic hydrogen at these redshifts has now been detected in emission.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-2 av 2

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy