260 research outputs found

    A Simple Model For the Intermolecular Interactions in Halogene Crystals

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    A simple effective atom-atom intermolecular potential for halogene solids (F2, Cl-, Br2 and 12) is proposed. The centers of inter action of the effective potential (6-exp type) are shifted from\u27 the atomic sites in order to reduce anisotropy of the intermolecular distances. The calculated results of the static properties for fluorine and chlorine are in good agreement with the experimental results. The calculated results for bromine and iodine crystals are less satisfactory. The limitations of the atom-atom model for description of the dynamical properties of halogene solids are also briefly discusse

    A Simple Model For the Intermolecular Interactions in Halogene Crystals

    Get PDF
    A simple effective atom-atom intermolecular potential for halogene solids (F2, Cl-, Br2 and 12) is proposed. The centers of inter action of the effective potential (6-exp type) are shifted from\u27 the atomic sites in order to reduce anisotropy of the intermolecular distances. The calculated results of the static properties for fluorine and chlorine are in good agreement with the experimental results. The calculated results for bromine and iodine crystals are less satisfactory. The limitations of the atom-atom model for description of the dynamical properties of halogene solids are also briefly discusse

    HELMINTH COMMUNITIES AND ECOLOGICAL APPRAISAL FOR THE CONDITION OF THE VELEKA RIVER, BLACK SEA REGION, BULGARIA

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    Abstract Biodiversity and ecological particularities of the parasite communities of the Black Sea Roach (Rutilus frisii (Nordmann, 1840)) and (Alburnus chalcoides (Güldenstädt, 1772

    Data Driven Root Cause Analyses in Multistage Manufacturing Utilising Life Cycle Wide Product Information

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    Root cause analyses in multistage manufacturing represents inspiration for constant improvement of existing methodologies and implementation of new ones. Using quality information data from manufacturing stage and customer perception, robust model that can be utilized in line in actual manufacturing plant is created. In this paper, a new approach for managing dimensional quality and improvement of the product geometry has been presented. New methodology was checked and then applied in major automotive factory

    Far Infrared and Raman Spectroscopic Investigations of the Lattice:Modes of Crystalline Thiophene

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    Vibrational spectroscopic measurements combined with the lattice statics and lattice mod es calculations have been applied in order to derive the most probable structure of the low temperature (stable) phase V of thiophene (below 112 K). The far infrared spectrum has been recorded from 135 to 30 cm? of this phase of thiophene at 20 K. The low frequency Raman spectrum from 150 to 10 cm" has also been record ed for the phase V at 35 K. From the fact that there is coincidence between lattice mode frequencies observed in the infrared and Raman spectra, one can exclude centrosymmetric space groups. The observations of 20 lattice modes in the Raman spectrum and 14 modes in the FIR spectrum eliminate the possibility of tetragonal symmetry, but the data are consistent with orthorhombic symmetry with the unit cell containing 4 molecules on Cl sites. In spite of the glassy-like transition observed for this phase at 42 K, both spectra bear striking resemblance to the typical low frequency spectra of molecular crystals. Therefore, it is assumed, for the purposes of the static and dynamic studies, that the thiophene in phase V can be considered as an ideally ordered crystal. Calculations of the lattice energy and lattice mode frequencies, based on the atom-atom potential, appear to be most consistent with space group Pca2l (C2v5) which is in agreement with most of the earlier predictions made for the structure of the thiophene phase V. The Raman spectrum of the metastable phase II2 is also given

    Far Infrared and Raman Spectroscopic Investigations of the Lattice:Modes of Crystalline Thiophene

    Get PDF
    Vibrational spectroscopic measurements combined with the lattice statics and lattice mod es calculations have been applied in order to derive the most probable structure of the low temperature (stable) phase V of thiophene (below 112 K). The far infrared spectrum has been recorded from 135 to 30 cm? of this phase of thiophene at 20 K. The low frequency Raman spectrum from 150 to 10 cm" has also been record ed for the phase V at 35 K. From the fact that there is coincidence between lattice mode frequencies observed in the infrared and Raman spectra, one can exclude centrosymmetric space groups. The observations of 20 lattice modes in the Raman spectrum and 14 modes in the FIR spectrum eliminate the possibility of tetragonal symmetry, but the data are consistent with orthorhombic symmetry with the unit cell containing 4 molecules on Cl sites. In spite of the glassy-like transition observed for this phase at 42 K, both spectra bear striking resemblance to the typical low frequency spectra of molecular crystals. Therefore, it is assumed, for the purposes of the static and dynamic studies, that the thiophene in phase V can be considered as an ideally ordered crystal. Calculations of the lattice energy and lattice mode frequencies, based on the atom-atom potential, appear to be most consistent with space group Pca2l (C2v5) which is in agreement with most of the earlier predictions made for the structure of the thiophene phase V. The Raman spectrum of the metastable phase II2 is also given

    Risk Model for Integrated Management System

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    The purpose of this paper is to develop an integrated risk management model for standardized management systems: ISO 9001:2015 for quality management, ISO 14001:2015 for environmental management, ISO/IEC 27001:2013 for information security management, ISO 45001:2018 for Occupational Health and Safety Management, and ISO 22000:2005 for food safety management in order to enable organizations can manage their processes and associated risks versus requirements of each internal and external stakeholder through only one MS instead of several individual MSs defined and implemented in an isolated way according to a specific MSS and hence to decrease the number of resources employed and to enhance the organization performance

    IxodIdae tIcks of small rumInants In the regIon of ParvomaI, southern BulgarIa

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    , 2014. ixodidae ticks of small ruminants in the region of parvomai, Southern Bulgaria. Bulg. J. Agric. Sci., The species composition and the distribution of ticks from the family Ixodidae, invading domestic goats (Capra aegagrus hircus) and sheep (Ovis aries) near parvomay (region of plovdiv) were studied. The indicators of an invasion (extension invasion and intensity of invasion) and the seasonal changes in the invasion of goats and sheep by tick species were found out. The daily activity of Ixodes ricinus in a habitat near the Gradina village was observed. 637 specimens of goats and 810 specimens of sheep from 12 farms in different villages in the parvomay Municipality were examined, the study was conducted in all four seasons. it is found out that goats and sheep in the regions investigated is invaded by 7 species of ixodidae ticks -Rhipicephalus bursa, Rhipicephalus sanguineus, Ixodes ricinus, Dermacentor marginatus, Haemaphysalis sulcata, Haemaphysalis punctata and Hyaloma plumbeum. The predominant invasive species in both animals is Rhipicephalus bursa. The maximum of invasion in both host species was identified -in the spring by Ixodes ricinus and Dermacentor marginatus; in the summer -the species Rhipicephalus bursa and Rhipicephalus sanguineus; in the spring and autumn seasons -by Haemaphysalis sulcata and Haemaphysalis punctata. Single specimens from the species Hyaloma plumbeum were found in March and november. Changes in the daily activity of ticks of the species Ixodes ricinus were reported -related to the fluctuations of temperature and relative humidity and the solar radiation
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