The Constitution as Architecture: Legislative and Administrative Courts Under Article III

Symposium: Paul Bator: Legislative and Administrative Courts Under Article II

Polymeric Ablation Induced by Free Burning Arcs in Air

We investigate the influence of switching arcs on different polymers and their interaction. We describe a set of experiments on a simplified model geometry typical for low voltage switchgear. In a broad range of experimental conditions and parameters such as arc current, polymeric material or contact material, the voltage, the mass loss and the corresponding pressure build-up are examined. From this raw data, we deduce the arc influence on the ablation process as well as the feedback on some arc plasma properties

UMA ANALISE SIMPLES DA MAXIMIZAÇÃO DO BEM-ESTAR

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Laser ablation of ceramic Al2O3 at 193 nm and 248 nm: The importance of single-photon ionization processes

9 págs.; 8 figs.The aim of this work is to demonstrate that single-photon photoionization processes make a significant difference in the expansion and temperature of the plasma produced by laser ablation of ceramic Al2O3 in vacuum as well as to show their consequences in the kinetic energy distribution of the species that eventually will impact on the film properties produced by pulsed laser deposition. This work compares results obtained by mass spectrometry and optical spectroscopy on the composition and features of the plasma produced by laser ablation at 193 nm and 248 nm, i.e., photon energies that are, respectively, above and below the ionization potential of Al, and for fluences between threshold for visible plasma and up to ≈2 times higher. The results show that the ionic composition and excitation of the plasma as well as the ion kinetic energies are much higher at 193 nm than at 248 nm and, in the latter case, the population of excited ions is even negligible. The comparison of Maxwell-Boltzmann temperature, electron temperatures, and densities of the plasmas produced with the two laser wavelengths suggests that the expansion of the plasma produced at 248 nm is dominated by a single population. Instead, the one produced at 193 nm is consistent with the existence of two populations of cold and hot species, the latter associated to Al+ ions that travel at the forefront and produced by single photon ionization as well as Al neutrals and double ionized ions produced by electron-ion impact. The results also show that the most energetic Al neutrals in the plasma produced at the two studied wavelengths are in the ground state. © 2013 AIP Publishing LLC.This work has been partially supported by project IZK0Z2 of the Swiss National Science Foundation. R.P. acknowledges a grant from the JAE-doc program, co-funded by European Social Fund.Peer Reviewe

Impact of Stark Shifts on the Radiation Cooling of Cu-Dominated Plasmas

We study the impact of Stark line shifts reported recently for Cu I transitions on the radiative cooling of Cu-dominated plasmas. The observed detuning in absorption between the hot core and cold shell of the arc leads to a reduction in radiation reabsorption compared to the case where Stark line shifts are neglected. Using a modeling based on a phenomenological treatment of the Stark line shift, we show that this reduction is below 2%