360 research outputs found

    Intermolecular interactions effects on magnetization tunnelling in molecular magnets

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    Using a pure quantum calculations and magnons approach, we investigated the magnetic properties of SMMs with crystal-field anisotropy. Our analysis introduces a clear physical mechanism for the appearance of the magnetic plateaus in the system which is related to tunnel and relaxation magnetization effects. We consider two cases of interest: when the SMM are completely independent and when there are inter-cluster magnetic couplings, especially super exchange and dipolar interactions. In such case, we give a special attention to single-ion anisotropies and dipole-dipole interactions. The dispersion relations and magnetization behaviours are explored and analyzed in the quantum magnons formalism taking into account the experimental reality and using commonly parameters values.Using a pure quantum calculations and magnons approach, we investigated the magnetic properties of SMMs with crystal-field anisotropy. Our analysis introduces a clear physical mechanism for the appearance of the magnetic plateaus in the system which is related to tunnel and relaxation magnetization effects. We consider two cases of interest: when the SMM are completely independent and when there are inter-cluster magnetic couplings, especially super exchange and dipolar interactions. In such case, we give a special attention to single-ion anisotropies and dipole-dipole interactions. The dispersion relations and magnetization behaviours are explored and analyzed in the quantum magnons formalism taking into account the experimental reality and using commonly parameters values

    ENERGY VALORIZATION OF OLIVE WASTE WATER, THEIR SLUDGE AND TREATMENT BY METHANE PRODUCTION

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    The anaerobic digestion of oil wastes water and the sludges of their treatment is a biological process that allows the production of energy in the form of biogas. Our study is based on the comparison of the methanogenic capacity between the biogas of the oil wastes water and the sludges of their treatment.Olive wastes water were previously treated by electrocoagulation and adsorption in optimal conditions. The sludge generated by the various treatments, estimated at 50 g/L of oil wastes water, is in turn treated by anaerobic digestion.The production of methane from the two wastes is accompanied by the reduction of their pollutant load evaluated in non-biodegradable organic matter, polyphenols and fat respectively by 39 %, 45 % and 39 % for sludge of oil wastes water and 36 %, 31 % and 39 % for oil waste water; a total yield of pollutant load of oil waste water from about 75 % to 78 %. The total amount of methane produced for 30 days and 49 days respectively by olive mill wastewater and their treatment sludge is 300.7 cm3/L and 889.9 cm3/L is an energy equivalent of 2.92 Wh/L and 8.72 Wh/L.The use of the anaerobic digestion process of oil wastes water treatment sludge is efficient and cost-effective for biogas production while eliminating their harmful effects on the environment.

    Impact of earthworm activity on the chemical fertility of irrigated soil with urban effluents

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    The reuse of urban effluents to irrigate the soils of peri-urban grasslands in the vicinity of the town of Setif (northeastern Algeria) is an old and widespread practice. In this context, the present study was conducted to evaluate the effect of the irrigation with urban effluents on the biological and chemical behavior of soils. Effluents analysis showed significant organic and particulate pollution, the latter contributed to earthworm abundance and increased the richness of irrigated soils with nutrients. The analysis of turricules revealed the role of earthworms through the activity of bioturbation in the increase of the rate of organic matter as well as in the bioavailability of the nutrients of the irrigated soils. In space, permanent vegetation cover has played an important role as a biofilter. This was confirmed by the inter-site differences recorded through the measured variables particularly organic ones.Keywords: Natural grasslands, urban effluents, earthworm activity, turricles, organic matte

    Assessment of organo-mineral fraction during co-composting of sewage sludge-lignocellulosic waste by XRD and FTIR analysis

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    This investigation focuses mainly on highlighting the contribution of the IR spectrum of the mineral matrix in co-composts after removing the organic phase by slow pyrolysis. The mineral matrix is still confusion subject in the interpretation of FTIR spectra of co-composts. The XRF and XRD analysis of the low pyrolysis substrates of sewage sludge and date palm waste during six months of co-composting, show that the mineral fraction is homogeneous in the samples and that the inorganic matrix consists mainly of silica and carbonates including a residual portion remaining after pyrolysis.The comparison of FTIR spectra of heated samples at 105°C and 650°C shows that the 3500-3280 cm-1 region characterises essentially the hydroxyl groups OH (ν(OH)) of water molecules. The observed bands in this region provide information on the co-compost hydrophilic nature but can only provide limited information about the humic substances composition. The band at 1035 cm-1, assigned commonly to organic material, which persists after the thermal treatment, should be assigned for the Si-O vibration of silica

    Morphological and chemical characterization of carob pulps collected from four moroccan regions

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    The present research is included in a strategy of conservation and management of genetic resources for Carob tree (Ceratonia Siliqua L.) in Morocco. It has as one of its objectives, the evaluation of the morphological and chemical characteristics of four Moroccan ecotypes of carob pulps. The study related to morphological characterization reveals that there was a significant difference between the four populations from Meknes, Fez, Khemisset and Marrakech collected in 2018 and 2019. The lipid profile of carob pulp extracts analyzed by GC-MS is constituted of fatty acids, hydrocarbons, non-oxygenated compounds, sterols and tocopherols. The concentration of these compounds varies according to the population and year of collection. According to the results, the fatty acid contents are relatively high in 2019 with the dominance of palmitic acid. Additionally, our study approved the dominance of 1-Hexacosene, Tetracosane, Heptadecane. 1-iodo Hexadecane, 1-chloro Octadecane and 1, 54-dibromo Tetrapentacontane. Furthermore, it is noted that Stigmasterol, gamma-Sitosterol, beta-Sitosterol, alpha-Tocospiro A, alpha-Tocospiro B and Vitamin E are present in the samples. Moreover, the hierarchical analysis based on the results of the morphological and chromatographic characterization of the four populations’ pulps identify three groups. The first group included populations P3 and P4 respectively from Marrakech and Khemisset. The second group presented by the population P1 from Meknes. The population P2 from Fez constituted the third group

    Test of the CLAS12 RICH large scale prototype in the direct proximity focusing configuration

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    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c up to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Laboratory. The adopted solution foresees a novel hybrid optics design based on aerogel radiator, composite mirrors and high-packed and high-segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). We report here the results of the tests of a large scale prototype of the RICH detector performed with the hadron beam of the CERN T9 experimental hall for the direct detection configuration. The tests demonstrated that the proposed design provides the required pion-to-kaon rejection factor of 1:500 in the whole momentum range.Comment: 15 pages, 23 figures, to appear on EPJ

    First Measurement of Λ Electroproduction off Nuclei in the Current and Target Fragmentation Regions

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    We report results of Λ hyperon production in semi-inclusive deep-inelastic scattering off deuterium, carbon, iron, and lead targets obtained with the CLAS detector and the Continuous Electron Beam Accelerator Facility 5.014 GeV electron beam. These results represent the first measurements of the Λ multiplicity ratio and transverse momentum broadening as a function of the energy fraction (z) in the current and target fragmentation regions. The multiplicity ratio exhibits a strong suppression at high zand an enhancement at low z. The measured transverse momentum broadening is an order of magnitude greater than that seen for light mesons. This indicates that the propagating entity interacts very strongly with the nuclear medium, which suggests that propagation of diquark configurations in the nuclear medium takes place at least part of the time, even at high z. The trends of these results are qualitatively described by the Giessen Boltzmann-Uehling-Uhlenbeck transport model, particularly for the multiplicity ratios. These observations will potentially open a new era of studies of the structure of the nucleon as well as of strange baryons

    First Exclusive Measurement of Deeply Virtual Compton Scattering off \u3csup\u3e4\u3c/sup\u3eHe: Toward the 3D Tomography of Nuclei

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    We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized 4He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling 4He nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only 4He Compton form factor, HA. This first measurement of coherent deeply virtual Compton scattering on the 4He nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei
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