Monitoring of grinding condition in drum mills based on resulting shaft torque

Grinding is the most energy-intensive process among all stages of raw material preparation and determines the course of subsequent ore beneficiation stages. Level of electricity consumption is determined in accordance with load characteristics forming as a result of ore destruction in the mill. Mill drum speed is one of process variables due to which it is possible to control ore destruction mechanisms when choosing speed operation mode of adjustable electric mill drive. This study on increasing energy efficiency due to using mill electric drive is based on integrated modelling of process equipment – grinding process and electromechanic equipment – electric drive of grinding process. Evaluating load torque by means of its decomposition into a spectrum, mill condition is identified by changing signs of frequency components of torque spectrum; and when studying electromagnetic torque of electric drive, grinding process is monitored. Evaluation and selection of efficient operation mode of electric drive is based on the obtained spectrum of electromagnetic torque. Research results showed that with increasing mill drum speed – increasing impact energy, load torque values are comparable for the assigned simulation parameters. From the spectra obtained, it is possible to identify mill load condition – speed and fill level. This approach allows evaluating the impact of changes in process variables of grinding process on parameters of electromechanical system. Changing speed operation mode will increase grinding productivity by reducing the time of ore grinding and will not lead to growth of energy consumption. Integration of digital models of the technological process and automated electric drive system allows forming the basis for developing integrated methods of monitoring and evaluation of energy efficiency of the entire technological chain of ore beneficiation

The effects of histone H4 tail acetylations on cation-induced chromatin folding and self-association

Understanding the molecular mechanisms behind regulation of chromatin folding through covalent modifications of the histone N-terminal tails is hampered by a lack of accessible chromatin containing precisely modified histones. We study the internal folding and intermolecular self-association of a chromatin system consisting of saturated 12-mer nucleosome arrays containing various combinations of completely acetylated lysines at positions 5, 8, 12 and 16 of histone H4, induced by the cations Na+, K+, Mg2+, Ca2+, cobalt-hexammine3+, spermidine3+ and spermine4+. Histones were prepared using a novel semi-synthetic approach with native chemical ligation. Acetylation of H4-K16, but not its glutamine mutation, drastically reduces cation-induced folding of the array. Neither acetylations nor mutations of all the sites K5, K8 and K12 can induce a similar degree of array unfolding. The ubiquitous K+, (as well as Rb+ and Cs+) showed an unfolding effect on unmodified arrays almost similar to that of H4-K16 acetylation. We propose that K+ (and Rb+/Cs+) binding to a site on the H2B histone (R96-L99) disrupts H4K16 ε-amino group binding to this specific site, thereby deranging H4 tail-mediated nucleosome–nucleosome stacking and that a similar mechanism operates in the case of H4-K16 acetylation. Inter-array self-association follows electrostatic behavior and is largely insensitive to the position or nature of the H4 tail charge modification

Refinement of the geological model of Jurassic deposits accounting the results of stochastic inversion and facies modeling

The paper presents the results of a comprehensive interpretation showing the effective way to integrate seismic data into a three-dimensional geological model. Stochastic inversion was used to increase the reliability of forecasts of productive thicknesses. A comprehensive interpretation of the geological and geophysical information of the Yu21 formation deposits of the Malyshevskaya formation was carried out, including sedimentological analysis of core data, petroelastic modeling of well logging curves for the purposes of stochastic inversion and stochastic inversion of seismic data. An areal forecast of sedimentation environments (facies) was carried out. The resulting three-dimensional geological model, in more detail, compared to the model without taking into account the spatial seismic forecast, emphasizes the heterogeneity of the distribution of properties in the geological environment, which is especially important when planning production drilling with horizontal wells

QUANTITATIVE STRUCTURE-METABOLISM RELATIONSHIP MODELING OF METABOLIC N-DEALKYLATION REACTION RATES

It is widely recognized that preclinical drug discovery can be improved via the parallel assessment of bioactivity, absorption, distribution, metabolism, excretion, and toxicity properties of molecules. High-throughput computational methods may enable such assessment at the earliest, least expensive discovery stages, such as during screening compound libraries and the hit-to-lead process. As an attempt to predict drug metabolism and toxicity, we have developed an approach for evaluation of the rate of N-dealkylation mediated by two of the most important human cytochrome P450s (P450), namely CYP3A4 and CYP2D6. We have taken a novel approach by using descriptors generated for the whole molecule, the reaction centroid, and the leaving group, and then applying neural network computations and sensitivity analysis to Quantitative structure-metabolism relationship (QSMR) models allow the estimation of complex metabolism-related phenomena from relatively simple calculated molecular properties or descriptors. Such models can be used for the design of structural analogs of bioactive compounds with improved pharmacokinetic properties (Bouska et al.

Coordination of Halide and Chalcogenolate Anions to Heavier 1,2,5-Chalcogenadiazoles: Experiment and Theory

New products of coordination of anions X^– (X = F, I, PhS) to the Te atom of 3,4-dicyano-1,2,5-telluradiazole (<b>1</b>) were synthesized in high yields and characterized by X-ray diffraction (XRD) as the salts [(Me₂N)₃S]⁺[<b>1</b>-F]⁻ (<b>9</b>), [K­(18-crown-6)]⁺[<b>1</b>-I]⁻ (<b>10</b>), and [K­(18-crown-6)]⁺[<b>1</b>-SPh]⁻<b>·</b>THF (<b>11</b>), respectively. In the crystal lattice of <b>10</b>, I atoms are bridging between two Te atoms. The bonding situation in anions of the salts <b>9</b>–<b>11</b> and some other adducts of 1,2,5-chalcogenadiazoles (chalcogen = S, Se, Te) and anions X^– (X = F, Cl, Br, I, PhS) was studied using DFT, QTAIM, and NBO calculations, for <b>9</b>–<b>11</b> in combination with UV–vis, IR/Raman, and MS-ESI techniques. In all cases, the nature of the coordinate bond is negative hyperconjugation involving the transfer of electron density from X^– to the heterocycles. The energy of the bonding interaction varies in a range from ∼30 kcal mol^–1 comparable with energies of weak chemical bonds (e.g., internal N–N bond in organic azides) to ∼86 kcal mol^<b>–</b>1 comparable with an energy of the C–C covalent bonds. The thermodynamics of the anions’ coordination to <b>1</b> and their Se and S congeners was also studied by quantum chemical calculations. The general character of this reaction and favorable thermodynamics in the case of heavier chalcogens (Se, Te) were established. Comparison with available data on acyclic analogues, i.e. the chalcogen diimines RNXNR, reveals that they also coordinate various anions but in addition reactions across XN (X = S, Se, Te) double bonds. Attempts to prepare the anion [<b>1</b>-TePh]⁻ led to disintegration of <b>1</b>. The only unambiguously identified product was a rather rare tellurocyanate that was characterized by XRD and elemental analysis as the salt [K­(18-crown-6)]⁺[TeCN]⁻ (<b>13</b>)

High resolution 3D visualization of the spinal cord in a post-mortem murine model

International audienceA crucial issue in the development of therapies to treat pathologies of the central nervous system is represented by the availability of non-invasive methods to study the threedimensional morphology of spinal cord, with a resolution able to characterize its complex vascular and neuronal organization. X-ray phase contrast micro-tomography enables a highquality, 3D visualization of both the vascular and neuronal network simultaneously without the need of contrast agents, destructive sample preparations or sectioning. Until now, high resolution investigations of the post-mortem spinal cord in murine models have mostly been performed in spinal cords removed from the spinal canal. We present here post-mortem phase contrast micro-tomography images reconstructed using advanced computational tools to obtain high-resolution and high-contrast 3D images of the fixed spinal cord without removing the bones and preserving the richness of micro-details available when measuring exposed spinal cords. We believe that it represents a significant step toward the in-vivo application. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen