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BACKGROUND: The present work describes the facile, fast and economic base‐catalyzed acylation of benzenediols with vinyl acetate. The Hirshfeld surface analysis of benzene‐1,4‐diol O,O′‐diacetate is also described. NaOH, KOH and K2CO3 were the bases used for the catalysis of the acylation of benzene‐1,x‐diols (x = 2, 3, 4) with vinyl acetate to obtain the corresponding O,O′‐diacetyl derivatives. RESULTS: The yields were quite good, up to 99% under solvent‐free conditions. This method represents an alternative 'green' process for the preparation of O‐acetyl derivatives of hydroxyaryls. The benzene‐1,4‐diol O,O′‐diacetate crystal structure was obtained and described using Hirshfeld surface analysis. A noticeable contribution of the C⋯H contacts is shown (16.7%), despite the insignificant area of the Hirshfeld surface occupied by the carbon atoms (9.4%). By using two‐dimensional fingerprint plots, it was proved that C⋯H contacts were due to the presence of π‐stacking. The O⋯H contacts (41.4%) were the most numerous ones, relating mainly to typical hydrogen bonds (de + di ≈ 2.6 Å). The high saturation of the C⋯H and O⋯H contacts (enrichment ratios (E) = 1.30 and 1.36, respectively), despite their smaller contribution to the overall surface as compared to the H⋯H contacts (E = 0.84), is shown. CONCLUSION: The novelty of this work is the development of a method based on an inexpensive, safe and easy‐to‐use catalyst (K2CO3). This method is fast with high yields. Besides, it may be used for acylation at an industrial scale. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

This paper presents the principles of the designing metal working machine tools mechatronic systems of surface generation which are optimal from the point of view of reproducing given part profiles. It is shown that the degree of their optimality is determined by the proximity of their characteristics to the frequency characteristics of an ideal low-pass filter. Mathematical methods for building compact mathematical models of the drive hardware, adequately describing the inertial and elastic characteristics of the elements of its structure, is described. These models are convenient for simulating control loops of the machine tools feed drives. A method for the parametric synthesis of a two-mass mathematical model of a subordinate control system for a feed drive with an elastic-dissipative coupling between equivalent lumped masses which simulate a moving unit and rotating elements of the drive mechanism is proposed. The synthesis problem is reduced to solving a system of nonlinear equations. Examples to demonstrate the proposed methods and models capabilities are given.

Selection of direct drives for tool and workpiece rotation based on their computed torques for gear-hobbing machines of new generation is considered. Significant influence of torsional stiffness of electromechanical drive system, their tuning and peculiarities of operation in the continuous tracking mode on the drives' maximum torque is shown.

Despite a long history of research, there is almost no information regarding the major biogeochemical fluxes that could characterize the past and present state of the European Lake Onego ecosystem and be used for reliable prognostic estimates of its future. To enable such capacity, we adapted and implemented a three-dimensional coupled hydrodynamical biogeochemical model of the nutrient cycles in Lake Onego. The model was used to reconstruct three decades of Lake Onego ecosystem dynamics with daily resolution on a 2 x 2 km grid. A comparison of available information from Lake Onego and other large boreal lakes proves that this hindcast is plausible enough to be used as a form of reanalysis. As new regional phenological knowledge, the reanalysis quantifies that the spring phytoplankton bloom, previously overlooked, reaches a maximum of 500 ± 128 mg C m-2 d-1 in May, contributes to approximately half of the lake's annual primary production of 17.0-20.6 g C m-2yr-1, and is triggered by increasing light availability rather than by an insignificant rise in water temperature. Coherent nutrient budgets provide reliable estimates of phosphorus and nitrogen residence times of 47 and 17 years, respectively. The shorter nitrogen residence time is explained by sediment denitrification, which in Lake Onego removes over 90% of the bioavailable nitrogen input, but is often ignored in studies of other large lakes. This model can be used for longterm projections as soon as the corresponding scenarios of climate change and socio-economic development become available for north-western Russia. [ABSTRACT FROM AUTHOR]

A family of thiourea based derivatives, RNHC(S)NHP(S)(OiPr)2 [R = Ph (YEZNUN), 2‐MeC6H4 (AQOYAH), 2,5‐Me2C6H3 (WARREO), 2,6‐Me2C6H3 (GUJGUO), 2,4,6‐Me3C6H2 (AQOYEL), PhNH (QORXUR), 1‐naphthyl (MOWPEU)], has been studied to understand the synergy between dihydrogen and other (non)conventional non‐covalent interactions. It was established that all monomers are stabilized through intramolecular dihydrogen C–H···H–C interactions. Additionally, C–H···π interactions are noted in AQOYAH, WARREO, and MOWPEU; N–H···O interactions in AQOYAH, and WARREO; C–H···S interactions in GUJGUO, YEZNUN, and AQOYEL; N–H···S interactions in GUJGUO, AQOYEL, MOWPEU, and YEZNUN; and N–H···N interactions in QORXUR. The crystal structures of all the thioureas are further stabilized by the most pronounced intermolecular C–H···H–C interactions followed by N–H···S and C–H···S with the formation of centrosymmetric R22(8) dimers. These non‐covalent interactions are augmented by the π···π stacking in YEZNUN and MOWPEU; C–H···π in WARREO, GUJGUO, AQOYEL and MOWPEU; N–H···π in QORXUR. The synergy between intra‐ and intermolecular C–H···H–C and other types of non‐covalent interactions lead to the extraordinary stability of these systems as indicated by the ETS‐NOCV Scheme Although the London dispersion forces cover ≈ 70–80 % of the overall C–H···H–C stabilization, the covalent‐like charge delocalization based on depletion of electron charge from the σ(C–H) orbitals to the inter‐atomic H···H region contributes notably up to 15 %. We have synthesized a new family of substituted thioureas RNHC(S)NHP(S)(OiPr)2 differing in donor‐acceptor properties of ancillary ligands (R = Ph, 2‐MeC6H4, 2,5‐Me2C6H3, 2,6‐Me2C6H3, 2,4,6‐Me3C6H2, PhNH, 1‐naphthyl) to study the nature and cooperativity of inter‐ and intramolecular hydrogen‐hydrogen close contacts together with other types of nonconventional non‐covalent interactions. [ABSTRACT FROM AUTHOR]

The results of the study aimed to assess the influence of future nuclear power plant "Hanhikivi-1" upon the local hydrological conditions in the Bothnian Bay in the Baltic Sea are presented. A number of experiments with different numerical models were also carried out in order to estimate the extreme hydro-meteorological conditions in the area of the construction. The numerical experiments were fulfilled both with analytically-specified external forcing and with real external forcing for two years: a cold year (2010) and a warm year (2014). The study has shown that the extreme values of sea level, water temperature, the characteristics of wind waves and sea ice in the vicinity of the future nuclear power plant can be significant and sometimes catastrophic. Permanent release of heat into the marine environment from operating nuclear power plant will lead to a strong increase in temperature and the disappearance of ice cover around 2 km vicinity of the station. These effects should be taken into account when assessing local climate changes in the future. [ABSTRACT FROM AUTHOR]