scholarly journals Effects of radiative losses on the relativistic jets of high-mass microquasars

Author(s):  
A. Charlet ◽  
R. Walder ◽  
A. Marcowith ◽  
D. Folini ◽  
J. Favre ◽  
...  
2008 ◽  
Vol 17 (10) ◽  
pp. 1819-1826
Author(s):  
PAUL DEMPSEY ◽  
PETER DUFFY

We investigate the acceleration and simultaneous radiative losses of electrons in the vicinity of relativistic shocks. Particles undergo pitch angle diffusion, gaining energy as they cross the shock by the Fermi mechanism and also emitting synchrotron radiation in the ambient magnetic field. Using a semi-analytic approach we find that the cut-off energy differs greatly from the nonrelativistic approximation. Our results also show that, while low energy particles remain nearly isotropic, high energy particles downstream of the shock have a large degree of anisotropy which increases with the Lorentz factor of the shock. The implications for the synchrotron emission of relativistic jets, such as those in microquasars and blazars, are discussed.


2020 ◽  
Author(s):  
Urbi Pal ◽  
Fangfang Chen ◽  
Derick Gyabang ◽  
Thushan Pathirana ◽  
Binayak Roy ◽  
...  

We explore a novel ether aided superconcentrated ionic liquid electrolyte; a combination of ionic liquid, <i>N</i>-propyl-<i>N</i>-methylpyrrolidinium bis(fluorosulfonyl)imide (C<sub>3</sub>mpyrFSI) and ether solvent, <i>1,2</i> dimethoxy ethane (DME) with 3.2 mol/kg LiFSI salt, which offers an alternative ion-transport mechanism and improves the overall fluidity of the electrolyte. The molecular dynamics (MD) study reveals that the coordination environment of lithium in the ether aided ionic liquid system offers a coexistence of both the ether DME and FSI anion simultaneously and the absence of ‘free’, uncoordinated DME solvent. These structures lead to very fast kinetics and improved current density for lithium deposition-dissolution processes. Hence the electrolyte is used in a lithium metal battery against a high mass loading (~12 mg/cm<sup>2</sup>) LFP cathode which was cycled at a relatively high current rate of 1mA/cm<sup>2</sup> for 350 cycles without capacity fading and offered an overall coulombic efficiency of >99.8 %. Additionally, the rate performance demonstrated that this electrolyte is capable of passing current density as high as 7mA/cm<sup>2</sup> without any electrolytic decomposition and offers a superior capacity retention. We have also demonstrated an ‘anode free’ LFP-Cu cell which was cycled over 50 cycles and achieved an average coulombic efficiency of 98.74%. The coordination chemistry and (electro)chemical understanding as well as the excellent cycling stability collectively leads toward a breakthrough in realizing the practical applicability of this ether aided ionic liquid electrolytes in lithium metal battery applications, while delivering high energy density in a prototype cell.


2020 ◽  
Vol 16 ◽  
Author(s):  
Chiara Fanali ◽  
Giovanni D’Orazio ◽  
Alessandra Gentili ◽  
Salvatore Fanali

: In this review paper, miniaturized techniques, including both electromigration and liquid chromatographic ones, have been considered discussing their main features in the analytical field for the separation and analysis of nonsteroidal anti-inflammatory drugs (NSAIDs). In capillary electrophoresis (CE) and nano-liquid chromatography (nano-LC), separation are performed in capillaries with internal diameter (I.D.) lower than 100 m and therefore flow rates in the range 100- 1000 nL/min are applied. Therefore due to the low flow rate, high mass sensitivity can be obtained. Usually conventional UV detectors are used on-line; however these techniques can be coupled with mass spectrometry (MS). CE and nano-LC have been also applied to the separation of NSAIDs using silica stationary phases (SP) modified with C18 promoting interaction with analytes mainly based on hydrophobic interaction. In addition the use of chiral SP resulted effective for the chiral resolution of these compounds. In addition to silica phases, monolithic (both organic and inorganic) material has also been used. Although most of the presented studies aimed to demonstrate the usefulness of the considered microfluidic techniques, some applications to real samples have also been reported.


2018 ◽  
Vol 9 (1) ◽  
pp. 133-139
Author(s):  
Waleed S. Mohammed ◽  
Ahmed H. El-Shazly ◽  
Marwa F. Elkady ◽  
Masahiro Ohshima

Introduction: The utilization of biodiesel as an alternative fuel is turning out to be progressively famous these days because of worldwide energy deficiency. The enthusiasm for utilizing Jatropha as a non-edible oil feedstock is quickly developing. The performance of the base catalyzed methanolysis reaction could be improved by a continuous process through a microreactor in view of the high mass transfer coefficient of this technique. Materials & Methods: Nanozirconium tungstovanadate, which was synthetized using sol-gel preparation method, was utilized in a complementary step for biodiesel production process. The prepared material has an average diameter of 0.066 &µm. Results: First, the NaOH catalyzed methanolysis of Jatropha oil was investigated in a continuous microreactor, and the efficient mixing over different mixers and its impact on the biodiesel yield were studied under varied conditions. Second, the effect of adding the nanocatalyst as a second stage was investigated. Conclusion: The maximum percentage of produced methyl esters from Jatropha oil was 98.1% using a methanol/Jatropha oil molar ratio of 11 within 94 s using 1% NaOH at 60 &°C. The same maximum conversion ratio was recorded with the nanocatalyst via only 0.3% NaOH.


2020 ◽  
Vol 451 ◽  
pp. 116313 ◽  
Author(s):  
Kenneth W. Lee ◽  
Gregory S. Eakins ◽  
Mark S. Carlsen ◽  
Scott A. McLuckey

2005 ◽  
Vol 620 (2) ◽  
pp. 795-799 ◽  
Author(s):  
C. J. Lintott ◽  
S. Viti ◽  
J. M. C. Rawlings ◽  
D. A. Williams ◽  
T. W. Hartquist ◽  
...  
Keyword(s):  

2020 ◽  
Vol 496 (1) ◽  
pp. 638-648 ◽  
Author(s):  
Timo L R Halbesma ◽  
Robert J J Grand ◽  
Facundo A Gómez ◽  
Federico Marinacci ◽  
Rüdiger Pakmor ◽  
...  

ABSTRACT We investigate whether the galaxy and star formation model used for the Auriga simulations can produce a realistic globular cluster (GC) population. We compare statistics of GC candidate star particles in the Auriga haloes with catalogues of the Milky Way (MW) and Andromeda (M31) GC populations. We find that the Auriga simulations do produce sufficient stellar mass for GC candidates at radii and metallicities that are typical for the MW GC system (GCS). We also find varying mass ratios of the simulated GC candidates relative to the observed mass in the MW and M31 GCSs for different bins of galactocentric radius metallicity (rgal–[Fe/H]). Overall, the Auriga simulations produce GC candidates with higher metallicities than the MW and M31 GCS and they are found at larger radii than observed. The Auriga simulations would require bound cluster formation efficiencies higher than 10 per cent for the metal-poor GC candidates, and those within the Solar radius should experience negligible destruction rates to be consistent with observations. GC candidates in the outer halo, on the other hand, should either have low formation efficiencies, or experience high mass-loss for the Auriga simulations to produce a GCS that is consistent with that of the MW or M31. Finally, the scatter in the metallicity as well as in the radial distribution between different Auriga runs is considerably smaller than the differences between that of the MW and M31 GCSs. The Auriga model is unlikely to give rise to a GCS that can be consistent with both galaxies.


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