82 research outputs found

    Radiation-Induced Degradation of Organic Compounds and Radiation Technologies for Purification of Aqueous Systems

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    Environmental application of radiation technologies is an important part of radiation processing. Radiation treatment of aqueous systems contaminated with organic compounds is a promising method of water and wastewater purification and corresponding technologies are being developed. In this chapter, the following aspects of radiation treatment process are considered: sources of contamination and major contaminants of water and wastewater; primary processes in aqueous systems initiated by ionizing radiation; principal ways of contaminant conversion as consequences of primary processes (complete mineralization of organic compounds, partial decomposition of organic molecules resulted in detoxification, decolorization, disinfection of polluted water, and improvement in biological degradation of contaminant, polymerization of monomers’ contaminants, oxidation-reduction processes, and coagulation of colloids); sources of ionizing radiation; and main equipment applied in radiation technologies of aqueous system purification

    Duality in multi-channel Luttinger Liquid with local scatterer

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    We have devised a general scheme that reveals multiple duality relations valid for all multi-channel Luttinger Liquids. The relations are universal and should be used for establishing phase diagrams and searching for new non-trivial phases in low-dimensional strongly correlated systems. The technique developed provides universal correspondence between scaling dimensions of local perturbations in different phases. These multiple relations between scaling dimensions lead to a connection between different inter-phase boundaries on the phase diagram. The dualities, in particular, constrain phase diagram and allow predictions of emergence and observation of new phases without explicit model-dependent calculations. As an example, we demonstrate the impossibility of non-trivial phase existence for fermions coupled to phonons in one dimension

    Numerical simulation of mesomechanical behavior of porous brittle materials

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    The influence of the types of porous structure on the features of deformation, damage accumulation and fracture of mesovolumes of brittle materials is studied. At the mesoscale, the pores of different shape are taken into account explicitly. The digital models were made using random values of coordinates and radii of spherical voids or solid spheres. For numerical modeling of the mechanical behavior up to failure, the evolutionary approach is applied with considering the nonlinear constitutive equations to describe damage accumulation and its influence on the degradation of the strength properties of the frame of porous ceramics. The calculated averaged stress-strain diagrams were shown to be sensitive not only to the value of porosity but also to the shape of pores. The simulation results are validated with experimental data for zirconia and alumina ceramics. Good qualitative and quantitative agreement of modeling results with experimental data suggests that taking into account of two-scale porosity in the form of explicit consideration of large pores at the mesoscale and implicit integrated consideration of tiny pores and cracks from the microscale in the form of accumulated damage is quite sufficient in the framework of the hierarchical modeling

    Blow-up regimes in failure of rock specimens

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    For damage evaluation, the stage of superfast catastrophic failure of a medium and its mechanical behavior in a state of self-organized criticality prior to the onset of a blow-up fracture mode is of great interest for identification of its precursors. In this work, the data of experimental and numerical investigations of mechanical behavior of a medium before its catastrophic failure and the onset of a blow-up fracture mode are presented. Rock samples and ceramic specimens are subjected to three-point bending and uniaxial compression testing. Surface velocities of the loaded specimens are registered using a laser Doppler vibrometer. The blow-up regime duration is measured to be about 10–20β€…ms. The specimens’ mechanical behavior is numerically simulated under experimental conditions, including the regime of catastrophic fracture. The model parameters of damage accumulation are determined from a comparison with the experimental data. A number of features of the material mechanical response before the catastrophic fracture are identified, which could be treated as failure precursors

    The Use of Umbilical Cord Blood Nucleated Cells in the Treatment of Regressive Autism: A Case Report

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    BACKGROUND: Interest in the issue of childhood autism has surged in the recent decades. At the same time, despite the significant progress achieved in understanding the etiological and pathogenetic aspects of the condition, effective ways to treat it have continued to elude us. Stem cell therapy appears to hold great promise in the treatment and rehabilitation of patients with both neurological diseases (cerebral palsy, hydrocephalus) and mental disorders (autism, schizophrenia). METHODS: This article presents a case report describing the use of nucleated cord blood cells in a patient with regressive autism and resistance to standard therapies. The child’s condition was assessed before treatment and 6 and 12 months after. RESULTS: Clinical observation, psychometric, and instrumental diagnostic methods led to a significant improvement in the child’s condition in the form of perception development, reduction of somatosensory disorders, normalization of emotional status, and a development of social and communication skills. CONCLUSION: We assume that the result obtained may be associated with the normalization of the immunological status of our patient thanks to the cord blood cells therapy and consider it necessary to conduct further studies into the effectiveness of the method, taking the pathogenic mechanisms of autism into account

    Brittle porous material mesovolume structure models and simulation of their mechanical properties

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    To study the mechanical response of brittle porous materials at mesoscale, porous samples were generated and their deformation was numerically modelled. Two types of pore space morphology such as overlapping spherical pores and overlapping spherical solids were explicitly considered. For deformation modelling, an evolutionary approach including the nonlinear constitutive equations used to describe damage accumulation and its impact on the degradation of the solid frame strength properties was applied. The numerical results have shown that an average stress-strain diagram is sensitive to pore morphology as well as porosity
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