Search Results

You are looking at 1 - 10 of 307 items for :

  • Refine by Access: All Content x
Clear All

In the present paper a number of difficult passages in the poems of Catullus are discussed: carm. 1.9; 2.8; 4.23; 6.12/17; 10.9; 32.9–11; 36.9; 38.7s; 44.19/21; 54; 55. 13–22; 58b; 64. 219; 65. 5/8; 6.28/74; 67.1; 68.85; 80.8; 84.5; 100.6; 107.3; 110.7; 111.2; 113.7s.

Restricted access
Acta Microbiologica et Immunologica Hungarica
Authors: Bojan Pavlović, Dragana D. Božić, Jovica Milovanović, Ana Jotić, Vojko Djukić, Slobodanka Djukić, Neda Konstantinović, and Ivana Ćirković

biofilm on SS (category 2, ++) compared with non-multidrug resistant strains (category 1, +) ( p  < 0.05; Table  I , Figure  1b ). One (6.7%) S. aureus strain resistant to penicillin, ampicillin, and tetracycline, and three (20.0%) M. catarrhalis

Restricted access

Abstract  

Measurements of 222Rn (“radon”) in the environment are important in the geosciences and radiation-protection fields. We demonstrate here a simple laboratory-based calibration system to evaluate the efficiency of radon detectors with a reproducibility of about ±2%. The system uses a closed-loop air circulation design with 226Ra adsorbed onto MnO2-impregnated fiber as a radon source. Two RAD7 radon detectors (Durridge Co., Inc.) that were precisely calibrated at Durridge’s in-house calibration facility are used as secondary standards. By parallel analysis of the radon-enriched air within the closed loop, the test RAD7s are assigned a calibration coefficient to be applied to future measurements. We also performed a side-by-side intercomparison with two RAD7s in a high-radon natural environmental setting (limestone cave in Florida) that produced comparable results.

Restricted access

Abstract  

Sulfite and SeS2O 6 2− reduce SeO 3 2− in acidic solutions to selenium. Selenandisulfonates are observed as intermediate products. They are separated by high voltage paper ionophoresis in acidic basis electrolytes and identified on the paper by application of35S- and75Se-labelled compounds. The formation of selenandisulfonates depends on thepH of the solution. In neutral systems species exist with up to 4 Seatoms in the chain, in acidic solutions species with up to 7 Se-atoms in the chain are found. Se7S2O 6 2− has been detected for the first time. Selenium precipitates by the decomposition of the selenandisulfonates with the longest chains.

Restricted access

Abstract  

Nickel sulphide (NiS) was characterised using X-ray diffraction, thermal gravimetric analysis (TG) and differential scanning calorimetry (DSC). The 'as received' Millerite, stoichiometric NiS, observed to be slightly nickel deficient, was found to readily decompose in a nitrogen atmosphere at elevated temperatures (450C max.) to the sulphur deficient Godlevskite, Ni7S6. DSC and X-ray measurements demonstrated that the high temperature form of the Godlevskite was readily stabilised at room temperature. The kinetics of the α-β re-transformation in Godlevskite were then investigated using DSC and were observed to be first order.

Restricted access

<a name="abs1"/>Abstract??The high temperature sulfation of CaO with SO2was investigated under vacuum by TG. Experimental data indicated that the sulfation process was a two-stage reaction, a very fast surface reaction in the beginning, and followed by a product-layer diffusion-controlled reaction. The initial period was about 7 s. This process of sulfation was affected by type of limestone, micro structure, particle size and temperature, but hardly affected by SO2concentration. A 59% CaO conversion can be achieved in 30 s at 1000?C and 1 mbar.

Restricted access

Summary  

Using 224Ra radiotracer the first hydrolysis constant (pK1h) of Ra2+ cations has been determined. The pK1h value of Ra2+ was compared with the pK1h values of other Group 2 cations. It has been shown that the electrostatic hydrolysis model based on assumption that pK1h is a linear function of reciprocal ionic radii (1/r i) does not describe well the hydrolysis of Group 2 metal cations. The reason of higher Ra2+ hydrolysis as expected is the influence of relativistic effects on bonding 7s and 7p 1/2 orbitals.

Restricted access

Abstract  

Oxo-centered mixed-valence trinuclear iron dicarboxylic acid complex iron fumarate [Fe3O(O2CCH=CHCO2)3(H2O)3nH2O (n = 18-19), have been synthesized firstly. Variable temperature Mössbauer spectroscopy has been carried out to elucidate the rate of intramolecular electron transfer. It was found that the complex showed a temperature dependent mixed-valence state. At low temperature two quadrupole split doublets were observed corresponding to high spin Fe(III) and high spin Fe(II) state and a complete averaged valence state was observed at about 270 K. At temperatures between 200 and 270 K the spectra showed relaxation effect as the electron transfer rate was comparable to the Mössbauer timescale (-10–7 s).

Restricted access

Abstract  

The terpenes α-(+)-pinene, and α-(−)pinene have been radiolyzed at radiation doses of 150, 300 and 600 kGy. The radiolyzed samples have been analyzed by FT-IR spectroscopy and polarimetry. Both α-(+)-, α-(−)-pinenes show a linear trend to radioracemization as a function of the radiation dose administered ≈2.5·10−3 [α]D/kGy. The solvent fractionation and the liquid chromatographic analysis (HPLC) of the radiolyzed samples shows that both α-pinene enantiomers produce ocimene and dipentene together with minor quantities of other products and a resin. The kinetics of α-pinene decomposition under radiolytic conditions can be described by a pseudofirst order rate constant k∼5.3·10−7s−1 while the radiation chemical yield for the same reaction has a G = 5.0 molecules/100 eV, so that about 30% of the original α-pinene is converted into other products at 600 kGy.

Restricted access