Search results for "Argo"

Gas jet studies towards an optimization of the IGISOL LIST method

2011

Abstract Gas jets emitted from an ion guide have been studied as a function of nozzle type and gas cell-to-background pressure ratio in order to obtain a low divergent, uniform jet over a distance of several cm. The jet has been probed by imaging the light emitted from excited argon or helium gas atoms. For a simple exit hole or converging-diverging nozzle, the jet diameter was found to be insensitive to the nozzle shape and inlet pressure. Sonic jets with a FWHM below 6 mm were achieved with a background pressure larger than 1 mbar in the expansion chamber. The measurements are supported by the detection of radioactive 219 Rn recoils from an alpha recoil source mounted within the gas cell.…

Surface investigation of plasma HMDSO membranes post-treated by CF4/Ar plasma

2002

Fluorination treatment has been performed on polysiloxane membranes using a plasma glow discharge of a gases mixture CF4 and argon (plasma enhanced chemical vapor deposition). Atomic force microscopy, XPS analyses and contact angle measurements have been undertaken to explain the surface transformation and behavior, which strongly depend on the morphology, the composition and the hydrophilic/hydrophobic character of the plasma-polymerized initial membranes. Main result is that fluorination, which leads to hydrophobic membranes, has a more relevant effect on amorphous silica-like membranes than on polymer-like ones, according to their chemical composition whereas the plasma surface reaction …

Hydrodynamics of the cocurrent downflow of a gas and a foaming liquid through a packed bed. Part I. Estimation of the transition boundary between the…

2004

Abstract In the study the results of investigations are presented aimed at determining such values of the operating parameters for which the change of the hydrodynamic regime occurs from the gas continuous flow (GCF) to the pulsing flow (PF). Nitrogen, helium and argon were used as the gas phase while the liquid phase was formed by the aqueous solutions of the alcohols C 1 –C 4 of the concentrations which ensured the foaming of the system. Thus a wide range of physicochemical properties of the system was covered in the experiments. The present study, as well as Part II, contain a wealth of experimental data which characterise the PF through the packing for the foam-forming systems. It is de…

Unprecedented layered coordination polymers of dithiolene group 10 metals: Magnetic and electrical properties

2016

One-pot reactions between Ni(ii), Pd(ii) or Pt(ii) salts and 3,6-dichloro-1,2-benzenedithiol (HSC6H2Cl2SH) in KOH medium under argon lead to a series of bis-dithiolene coordination polymers. X-ray analysis shows the presence of a common square planar complex [M(SC6H2Cl2S)2]2- linked to potassium cations forming either a two-dimensional coordination polymer network for {[K2(μ-H2O)2(μ-thf)(thf)2][M(SC6H2Cl2S)2]}n [M = Ni (1) and Pd (2)] or a one-dimensional coordination polymer for {[K2(μ-H2O)2(thf)6][Pt(SC6H2Cl2S)2]}n (3). In 3 the coordination environment of the potassium ions may slightly change leading to the two-dimensional coordination polymer {[K2(μ-H2O)(μ-thf)2][Pt(SC6H2Cl2S)2]}n (4) …

Juan Bautista Hermán: discípulo de Gregorio Mayans. Los entresijos de la curia valenciana. Una persecución en dos actos

1998

Pelargonium leaves as bioaccumulator of polynuclear aromatic hydrocarbons: Analysis and evaluation of sources and air quality in Palermo area

2006

The leaves of Pelargonium zonale have been chosen because this plant is widespread in both the Mediterranean metropolitan and peripheral areas. The paper describes the analytical method, and the results concerning the determination of PAHs in Pelargonium leaves collected in the Palermo area, and their possible origins. The GC-MS method was applied, since identification of all the different compounds with spectra libraries is possible. Samples were analyzed for 22 PAHs. The reported analytical method is complete within 2 hours, and more convenient than that of other researches. Total PAH concentrations in leaves varied between 24-357 g/kg d.w. The relative abundance of the analyzed PAHs can …

2021

FTIR spectroscopy was combined with the matrix isolation technique and quantum chemical calculations with the aim of studying complexes of isocyanic acid with sulfur dioxide. The structures of the HNCO⋯SO2 complexes of 1:1, 1:2 and 2:1 stoichiometry were optimized at the MP2, B3LYPD3, B2PLYPD3 levels of theory with the 6-311++G(3df,3pd) basis set. Five stable 1:1 HNCO⋯SO2 complexes were found. Three of them contain a weak N-H⋯O hydrogen bond, whereas two other structures are stabilized by van der Waals interactions. The analysis of the HNCO/SO2/Ar spectra after deposition indicates that mostly the 1:1 hydrogen-bonded complexes are present in argon matrices, with a small amount of the van de…

Readiness of the ATLAS liquid argon calorimeter for LHC collisions

2010

The ATLAS liquid argon calorimeter has been operating continuously since August 2006. At this time, only part of the calorimeter was readout, but since the beginning of 2008, all calorimeter cells have been connected to the ATLAS readout system in preparation for LHC collisions. This paper gives an overview of the liquid argon calorimeter performance measured in situ with random triggers, calibration data, cosmic muons, and LHC beam splash events. Results on the detector operation, timing perfor-mance, electronics noise, and gain stability are presented. High energy deposits from radiative cosmic muons and beam splash events allow to check the intrinsic constant term of the energy resolutio…

A 4 tonne demonstrator for large-scale dual-phase liquid argon time projection chambers

2018

A 10 kilo-tonne dual-phase liquid argon TPC is one of the detector options considered for the Deep Underground Neutrino Experiment (DUNE). The detector technology relies on amplification of the ionisation charge in ultra-pure argon vapour and offers several advantages compared to the traditional single-phase liquid argon TPCs. A 4.2 tonne dual-phase liquid argon TPC prototype, the largest of its kind, with an active volume of \three has been constructed and operated at CERN. In this paper we describe in detail the experimental setup and detector components as well as report on the operation experience. We also present the first results on the achieved charge amplification, prompt scintillat…

Line Identification of Atomic and Ionic Spectra of Holmium in the Near-UV. II. Spectra of Ho ii and Ho iii

2017

Fourier Transform spectra of holmium (Ho) in the UV spectral range from 31,530 to 25,000 cm−1 (317 to 400 nm) have been investigated, particularly focusing on the ionic lines. The distinction between the different degrees of ionization (I, II, and III) is based on differences in signal-to-noise ratios from two Ho spectra, which have been measured with different buffer gases, i.e., neon and argon. Based on 106 known Ho ii and 126 known Ho iii energy levels, 97 lines could be classified as transitions of singly ionized Ho and 9 lines could be classified as transitions of doubly ionized Ho. Of the 97 Ho ii lines, 6 have not been listed in the extant literature. Another 215 lines have been assi…