Study of Magnetic Superexchange in diluted Systems Znx Cd1-xCr2Se4 ( 0.35 ≤ x ≤ 0.58 )

The effects of cationic substitutions at different concentrations within the lattice Znx Cd1-xCr2Se4 (0.35≤x≤0.58) on the electronic transfer in chromium ions are investigated. For this propose, after taking into account the exchange integrals, we use the Anderson’s-Kanamori theory of superexchange to determine the transfer integrals bσσ and bπσ . With the use of the conventional molecular orbital model the covalency-mixing parameters, λσ and λπ, the electron spin transfer coefficients, ƒ i (i=σ, π, s ), and the total charge, C, transferred from ligand to the chromium ions, are evaluated. The variation of bσσ and bσπ with x agree with the passage of the system from ferromagnetic to antiferromagnetic order. For the compound presenting re-entrant behaviour (0.45≤x≤0.58), f s exhibits anomalous. The increasing in C with x is consistent with the expected decrease in covalency of the non magnetic cation in tetrahedral site.The effects of cationic substitutions at different concentrations within the lattice Znx Cd1-xCr2Se4 (0.35≤x≤0.58) on the electronic transfer in chromium ions are investigated. For this propose, after taking into account the exchange integrals, we use the Anderson’s-Kanamori theory of superexchange to determine the transfer integrals bσσ and bπσ . With the use of the conventional molecular orbital model the covalency-mixing parameters, λσ and λπ, the electron spin transfer coefficients, ƒ i (i=σ, π, s ), and the total charge, C, transferred from ligand to the chromium ions, are evaluated. The variation of bσσ and bσπ with x agree with the passage of the system from ferromagnetic to antiferromagnetic order. For the compound presenting re-entrant behaviour (0.45≤x≤0.58), f s exhibits anomalous. The increasing in C with x is consistent with the expected decrease in covalency of the non magnetic cation in tetrahedral site

Structure – properties study of sodium bismuth borate glasses

Sodium bismuth borate glasses with composition (100–x)(0.785B2O3–0.215Bi2O3)–xNa2O where x=0, 2, 4, 6, and 8 mol%, were prepared by standard synthesized melt–quenching method. The amorphous and vitreous nature of these samples was confirmed by X–ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis. The density of the samples was measured using Archimedes principle and the molar volumes were determined from the density data. The spectroscopic properties of glass samples were studied using Fourier Transform Infrared Spectrometer (FTIR) and Raman spectroscopic techniques. The density of the samples was found to vary non–linearly with the Na2O content, however, a slight variation of the glass transition temperature was observed. The addition of Na2O in 78.5B2O3–21.5Bi2O3 glass causes changes in the features of the FTIR and Raman spectra. Both types of IR and Raman spectroscopic revealed that the network structure of the studied glasses is mainly based on BO3 and BO4 units, and bismuth exists as BiO3 pyramidal and BiO6 octahedral units

Reconstruction of longitudinal electrons bunch profiles at FACET, SLAC

Work supported by funding from Universite Paris Sud, program "Attractivite" and by the ANR under contract ANR-12-JS05-0003-01 - http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/thpme093.pdfInternational audienceThe E-203 collaboration is testing a device on FACET at SLAC to measure the longitudinal profile of electron bunches using Smith-Purcell radiation [1]. At FACET the electron bunches have an energy of 20 GeV and a duration of a few hundred femtoseconds [2]. Smith-Purcell radiation is emitted when a charged particle passes close to the sur- face of a metallic grating. We have studied the stability of the measurement from pulse to pulse and the resolution of the measure depending on the number of gratings used

Corrosion Inhibition Influence of the Synthetized Chromen-6-One Derivatives on Mild Steel in 1.0 M HCl Electrolyte: Electrochemical, Spectroscopic and Theoretical Investigations

In this work, two new chromen-6-one derivatives (BCC), namely 7-phenyl-6H,7H-benzo[f]chromeno[4,3-b] chromen-6-one (BCC-Ph) and 7-(furan-2-yl)-6H, 7H-benzo[f] chromeno [4,3-b] chromen-6-one (BCC-Fur), were prepared and identified by spectroscopic technique (NMR). Their performances inhibitions were assessed by electrochemical measurements, and they confirmed and explained using scanning electron microscope combined with energy dispersive X-ray spectroscopy (SEM/EDX) and theoretical studies (DFT calculation and MD simulation). Both electrochemical techniques revealed that the obtained performance value rises with the content of inhibitors to reach 94.94% and 83.57% at 10-3 M BCC-Ph and BCC-Fur, correspondingly. Moreover, according to the PDP method, these compounds behave as mixed-type inhibitors in 1.0 M HCl medium. In addition, the influence of temperature indicated that the performance of the chromen-6-one derivatives slightly decreases with the temperature, and they are characterized by the physico-chemical adsorptions process with chemical dominance, and they act according to the Langmuir approach. The SEM/EDX analysis revealed a significant reduction of the heterogeneity of the metal surface by the establishment of anti-corrosive layer. Finally, the DFT calculations and MD simulation explain the mode of the chromen-6-one derivatives molecules adsorption, and confirm the obtained experimental results

Spectra of Coherent Smith-Purcell Radiation Observed from Short Electron Bunches: Numerical and Experimental Studies

MOPWA056 - ISBN978-3-95450-122-9International audienceThere is a significant interest in the development of compact particle accelerators within research areas including X-ray and THz (T-ray) sources of radiation, particle physics and medical sciences. To support the progress in these areas, non-invasive, electron beam diagnostics that are capable of measuring a single femtosecond electron bunch are required. At the current stage such beam diagnostics for femtosecond-long electron bunches are still not available. The goal of the work presented is to understand the spectral characteristics of coherent Smith-Purcell radiation to enable its quick and reliable interpretation including the longitudinal profile reconstruction of electron bunches. The research presented comprises results from numerical modelling and experimental studies. Using the numerical data, we discuss the radiated spectra dependence on the electron bunch profile and analyse the results. We also discuss the experimental data and compare it with theoretical predictions

Longitudinal Profile Monitor Using Smith-Purcell Radiation: Recent Results from the E-203 Collaboration

TUPC38 - Work supported by seed funding from the John Fell Fund, University of Oxford, Université Paris-Sud, program "Attractivité" and by the ANR under contract ANR-12-JS05-0003-01International audienceWe report on recent measurements made at FACET by the E-203 collaboration to test a longitudinal bunch profile monitor based on Coherent Smith-Purcell radiation. The capacity of this monitor to resolve sub-picosecond bunches will be shown as well as a comparison of profile reconstructed for different beam compression settings. We will also present recent electromagnetic simulations of the interactions between the beam and the grating as well as the expected resolution of such monitor. Comparison between Coherent Smith-Purcell radiation measurement and those made with other techniques will also be discussed. Finally future upgrades of the experiment and steps toward the construction of a single shot longitudinal profile monitor will be presented

Inhibicija rasta plijesni Aspergillus ochraceus ZMPBF 318 i Penicillum expansum ZMPBF 565 djelovanjem četiriju eteričnih ulja

Fungi produce a large variety of extracellular proteins, organic acids, and other metabolites and can adapt to several environmental conditions. Mycotoxin-producing moulds of the genera Aspergillus and Penicillium are common food contaminants. One of the natural ways to protect food from mould contamination is to use essential oils. In this study, we evaluated the effect of essential oils of cinnamon, lavender, rosemary, and sage at 1 % (v/v) concentration in yeast media inoculated with spores (fi nal concentration 106 mL-1 media) of Aspergillus ochraceus ZMPBF 318 and Penicillium expansum ZMPBF 565, alone or in combination, on fungal biomass. Cinnamon showed the best inhibitory effect (100 %). Lavender oil best inhibited the growth of Aspergillus ochraceus (nearly 100 %), and was less successful with Penicillium expansum (having dropped to 57 % on day 28). With cultivation time the inhibitory effect of sage and rosemary oil grew for Aspergillus ochraceus and dropped for Penicillium expansum. These results suggest that fungi can be controlled with essential oils, especially with cinnamon oil.Plijesni su poznate po svojoj visokoj sposobnosti proizvodnje različitih izvanstaničnih proteina, organskih kiselina i drugih metabolita i po svojoj mogućnosti prilagodbe na nepovoljne okolišne uvjete, a primjenjuju se i u obradi otpadnih voda. Plijesni iz rodova Aspergillus i Penicillium česti su kontaminanti u hrani i posebno opasne jer tvore toksične metabolite mikotoksine. Eterična ulja mogu se primijeniti kao prirodna sredstva za zaštitu hrane od kontaminacije plijesnima. U radu su prikazani rezultati istraživanja utjecaja eteričnih ulja cimeta, lavande, ružmarina i kadulje na kontrolu rasta biomase plijesni Aspergillus ochraceus ZMPBF 318 i Penicillium expansum ZMPBF 565, u obliku čistih i miješanih kultura. Ulja su dodavana u koncentraciji od 1 % (v/v), a podloga (kvaščev ekstrakt) bila je nacijepljena suspenzijama spora plijesni (106 mL-1 podloge). Eterično ulje cimeta pokazalo je najveći inhibitorni učinak (100 %). Inhibitorni učinak eteričnog ulja lavande bio je veći na rast Aspergillusa ochraceusa (skoro 100 %) nego Penicilliuma expansuma (57 %). Eterična ulja kadulje i ružmarina pokazala su suprotne učinke. Inhibitorni učinak na Aspergillus ochraceus tijekom perioda uzgoja je rastao, a na Penicillium expansum opadao. Rezultati pokazuju da se rast plijesni može kontrolirati primjenom eteričnih ulja, a posebno uljem cimeta. Također upućuju na ekonomsku vrijednost takvih tretmana