PHASE EQUILIBRIUM IN SYSTEM (LiF)2 – Li2CO3 – Li2SO4

The liquidus surface of the system (LiF)2-Li2SO4-Li2CO3 was studied by the calculated and differential thermal method of physicochemical analysis. An analysis of the systems of lower dimensionality of the facets of the investigated object showed that the most informative, for the experimental study, is the sections located in the crystallization field of lithium fluoride. A study of the DTA of a number of compositions located at the initially chosen polythermal section in the lithium fluoride crystallization field, the ratios of lithium sulfate and carbonate in the eutectic are determined. The composition of the triple eutectic was revealed by studying a non-invariant cut from the vertex of the triangle (LiF), through a point showing a constant ratio of sulfate and lithium carbonate in the eutectic, to the fusion of the thermal effects of the primary and tertiary crystallizations. The complexity of the study was that lithium carbonate is the most fusible component in the system, and according to the literature, after the melting of lithium carbonate, decomposition begins, which greatly complicates the interpretation of research results. In order to avoid the decomposition of lithium carbonate, each experimentally studied composition was heated to the melting temperature of lithium carbonate and kept in isothermal mode, at a temperature below its melting. Thus, the theoretical melting calculations and the region of location of the non-invariant composition have been extrapolated, allowing to limit the number of experimentally studied samples, and the subsequent experimental investigation of DTA of two polythermal sections revealed a eutectic composition crystallizing at 476 ° C and containing LiF-20 eq.%, Li2SO4 - 51 eq.%, Li2CO3 – 29 eq.%. The discrepancies between theoretical calculations and experimental studies are 8.3% in temperature and 5.05% in composition.

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Liquidus surface of the quasi-ternary system Cu2S–In2S3–FeS

Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases ◽

10.17308/kcmf.2021.23/3293 ◽

2021 ◽

Vol 23 (1) ◽

pp. 16-24

Author(s):

Ikhtiyar Bahram oglu Bakhtiyarly ◽

Ruksana Jalal kizi Kurbanova ◽

Shahri Seyfaly kizi Abdullaeva ◽

Ziyafat Mamed kizi Mukhtarova ◽

Fatmahanum Mamed Mammadova

Keyword(s):

Ternary System ◽

Binary Systems ◽

Liquidus Surface ◽

Equilibrium Points ◽

Experimental Studies ◽

Physicochemical Analysis ◽

Monovariant Equilibrium ◽

Binary Compounds ◽

Quasi Ternary System ◽

Primary Crystallisation

A projection of the liquidus surface of the quasi-ternary system Cu2S-In2S3-FeS was constructed as a result of experimental studies of quasi-binary and non-quasi-binary sections and based on the data on binary systems comprising a ternary system.Each section (six quasi-binary and four non-quasi-binary ones) was studied separately using complex methods of physicochemical analysis: differential thermal analysis, X-ray phase analysis, and microstructural analysis.It was found that the quasi-ternary system Cu2S-In2S3-FeS has six fields of primary crystallisation of separate phases and eleven monovariant equilibrium curves along which two phases are co-crystallised. Non-variant equilibrium points were obtained through the extrapolation of the direction of monovariant equilibrium curves.The quasi-ternary system Cu2S-In2S3-FeS is characterised by 17 non-variant equilibrium points, where Е1-Е5 are triple eutectic points.The projection diagram of the liquidus surface is characterised by three crystallisation fields of the initial componets (Cu2S, In2S3, FeS), four fields of binary compounds, and one field of a complex compound (CuFeIn3S6).Since complete solubility of the initial components in liquid and solid states is observed in the quasi-binary section CuIn5S8‑FeIn2S4, the fields of primary crystallisation of CuIn5S8 and FeIn2S4 are absent; they are replaced by an unlimited solid solution based on these components.The fields of primary crystallisation of Cu2S, FeS, and CuInS2 are the most extensive in the ternary system Cu2S-In2S3-FeS. The reactions occurring at monovariant equilibrium points are presented.

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Theoretical and experimental studies of palladium-catalyzed site-selective C(sp3)−H bond functionalization enabled by transient ligands

10.26434/chemrxiv.5717950 ◽

2017 ◽

Author(s):

Haibo Ge ◽

Lei Pan ◽

Piaoping Tang ◽

Ke Yang ◽

Mian Wang ◽

...

Keyword(s):

Bond Activation ◽

Theoretical Calculations ◽

Experimental Studies ◽

Bond Functionalization ◽

Aliphatic Ketones ◽

Site Selectivity ◽

Mechanistic Investigation ◽

Palladium Catalyzed ◽

Metal Catalyzed ◽

Site Selective

Transition metal-catalyzed selective C–H bond functionalization enabled by transient ligands has become an extremely attractive topic due to its economical and greener characteristics. However, catalytic pathways of this reaction process on unactivated sp3 carbons of reactants have not been well studied yet. Herein, detailed mechanistic investigation on Pd-catalyzed C(sp3)–H bond activation with amino acids as transient ligands has been systematically conducted. The theoretical calculations showed that higher angle distortion of C(sp2)-H bond over C(sp3)-H bond and stronger nucleophilicity of benzylic anion over its aromatic counterpart, leading to higher reactivity of corresponding C(sp3)–H bonds; the angle strain of the directing rings of key intermediates determines the site-selectivity of aliphatic ketone substrates; replacement of glycine with β-alanine as the transient ligand can decrease the angle tension of the directing rings. Synthetic experiments have confirmed that β-alanine is indeed a more efficient transient ligand for arylation of β-secondary carbons of linear aliphatic ketones than its glycine counterpart.

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PHASE EQUILIBRIA IN SYSTEM (LiF)2 – (NaCl)2 – Na3FSO4

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/tcct.20176010.5631 ◽

2017 ◽

Vol 60 (10) ◽

pp. 4

Author(s):

Sabina M. Omarova ◽

Zaira N. Verdieva ◽

Alibek B. Alkhasov ◽

Uhumaali G. Magomedbekov ◽

Patimat A. Arbukhanova ◽

...

Keyword(s):

Phase Equilibria ◽

Thermal Energy ◽

Crystallization Temperature ◽

Lithium Fluoride ◽

Eutectic Composition ◽

Polythermal Section ◽

Inert Gases ◽

Constant Ratio ◽

Starting Point ◽

Triple Eutectic

The liquidus surface of the quasi-triple system LiF–NaCl–Na3FSO4 was studied by a differential-thermal method of physicochemical analysis. As a result of the studies, the crystallization temperature (554 °C) and the composition of the three-component eutectic, which can be used as a heat accumulator in thermal energy storage devices, are determined. When designing plants based on renewable energy sources, it is necessary to provide storage tanks for the concentration of thermal energy, so that the stored heat energy can be used even in the period of absence of solar radiation. The most suitable for thermal accumulation are salt eutectic mixtures. Priority in this respect is research devoted to the development of compositions as possible with large values of the latent heat of the solid-liquid phase transition. The experiment was carried out on the synchronous thermal analysis unit STA 449 F3 Phoenix, the company Netzsch, designed to operate in the temperature range from room temperature to 1500 ° C in an atmosphere of inert gases (argon). All facet triangle (LiF)2 – (NaCl)2 – Na3FSO4: stable diagonal (LiF)2 – (NaCl)2 of the triple mutual system Li, Na // F, Cl and quasibinary systems: LiF–Na3FSO4; NaCl – Na3FSO4 is of the eutectic type, therefore it can be assumed that a triple eutectic is formed in the system. To determine the thermo physical characteristics of the eutectic composition, the experiment is planned in accordance with the general rules of the projection-thermographic method. The one-dimensional polythermal section AB located in the crystallization field of lithium fluoride, where A is 50% (LiF)2+ 50% Na3FSO4, B is 50% (LiF)2+ 50% (NaCl)2 was experientally studied. The study of the AB section reveals the direction to the triple eutectic, from the poles of lithium fluoride crystallization, i.e. the study of this section revealed a constant ratio of sodium chloride and sulfate-sodium fluoride in the triple eutectic. At the point showing a constant ratio of the two initial components in the eutectic, the thermal effects of the secondary and tertiary crystallizations are combined, and the primary crystallization is fixed at 657 °C. This composition is the starting point for the investigation of the next section. The content of lithium fluoride in the eutectic is determined by studying the polythermal section of lithium fluoride from the crystallization pole and passing through the projection Ē to the side of the triangle (NaCl)2 – Na3FSO4. As a result of the studies, the crystallization temperature and the concentration of the initial salts in the triple eutectic have been established. The detected eutectic composition (EΔ) crystallizes at 554 °C and contains eq. %: (LiF)2 – 26; (NaCl)2 – 23; Na3FSO4 – 51.Forcitation:Omarova S.M., Verdieva Z.N., Alkhasov A.B., Magomedbekov U.G., Arbukhanova P.A., Verdiev N.N. Phase equilibria in system (LiF)2 – (NaCl)2 – Na3FSO4. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 10. P. 4-8

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Research of stamping of unequal channel bars. Part 5. Methods for calculating the extrusion of channels. 2. Extrusion of non-strengthening material

10.36652/0042-4633-2021-10-46-52 ◽

2021 ◽

pp. 46-52

Author(s):

A.L. Vorontsov

Keyword(s):

Plane Strain ◽

Theoretical Calculations ◽

Experimental Studies ◽

High Accuracy ◽

Experimental Results ◽

Die Forging

The results of experimental studies on the extrusion of channels from non-strengthening material are presented. Comparison of theoretical calculations with experimental results showed the high accuracy of the derived formulas. Keywords: die forging, extrusion, punch, matrix, misalignment, plane strain. [email protected]

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Recovering Lithium from the Cathode Active Material in Lithium-Ion Batteries via Thermal Decomposition

Metals ◽

10.3390/met10040433 ◽

2020 ◽

Vol 10 (4) ◽

pp. 433

Author(s):

Shunsuke Kuzuhara ◽

Mina Ota ◽

Fuka Tsugita ◽

Ryo Kasuya

Keyword(s):

Lithium Ion Batteries ◽

Lithium Fluoride ◽

Active Material ◽

Lithium Ion ◽

Lithium Carbonate ◽

A Value ◽

Flow Test ◽

Percent Recovery ◽

Co2 Flow ◽

Recovered Material

In this study, calcination tests were performed on a mixed sample of lithium cobalt oxide and activated carbon at 300–1000 C under an argon atmosphere. The tests were conducted to discover an effective method for recovering lithium and cobalt from the cathode active material used in lithium-ion batteries. Additionally, the effect of soluble fluorine on the purification of lithium carbonate was investigated by the addition of lithium fluoride to an aqueous lithium hydroxide solution and a CO2 flow test was performed. The lithium recovery was ≥90% when the calcination occurred at temperatures of 500–600 C. However, the percent recovery decreased at temperatures ≥700 C. It was demonstrated that in order to increase the recovery while maintaining 99% purity of lithium carbonate in the recovered material, it was imperative to increase the temperature of the solution and to limit the F/Li ratio (mass%/mass%) in the solution to a value that did not exceed 0.05.

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Platinum–copper single atom alloy catalysts with high performance towards glycerol hydrogenolysis

Nature Communications ◽

10.1038/s41467-019-13685-2 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 33

Author(s):

Xi Zhang ◽

Guoqing Cui ◽

Haisong Feng ◽

Lifang Chen ◽

Hui Wang ◽

...

Keyword(s):

Active Sites ◽

High Performance ◽

Reaction Pathway ◽

Theoretical Calculations ◽

Experimental Studies ◽

Value Added ◽

Catalytic Performance ◽

Single Atom ◽

Glycerol Hydrogenolysis ◽

Single Atom Alloy

AbstractSelective hydrogenolysis of biomass-derived glycerol to propanediol is an important reaction to produce high value-added chemicals but remains a big challenge. Herein we report a PtCu single atom alloy (SAA) catalyst with single Pt atom dispersed on Cu nanoclusters, which exhibits dramatically boosted catalytic performance (yield: 98.8%) towards glycerol hydrogenolysis to 1,2-propanediol. Remarkably, the turnover frequency reaches up to 2.6 × 103 molglycerol·molPtCu–SAA−1·h−1, which is to our knowledge the largest value among reported heterogeneous metal catalysts. Both in situ experimental studies and theoretical calculations verify interface sites of PtCu–SAA serve as intrinsic active sites, in which the single Pt atom facilitates the breakage of central C–H bond whilst the terminal C–O bond undergoes dissociation adsorption on adjacent Cu atom. This interfacial synergistic catalysis based on PtCu–SAA changes the reaction pathway with a decreased activation energy, which can be extended to other noble metal alloy systems.

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Numerical simulation of the stress-strain state of complex-reinforced elements

Tehnički glasnik ◽

10.31803/tg-20190417112619 ◽

2019 ◽

Vol 13 (2) ◽

pp. 110-115

Author(s):

Olena Krantovska ◽

Mykola Petrov ◽

Liubov Ksonshkevych ◽

Matija Orešković ◽

Sergii Synii ◽

...

Keyword(s):

Numerical Simulation ◽

Strain State ◽

Theoretical Calculations ◽

Experimental Studies ◽

Theoretical Studies ◽

Stress Strain ◽

Narrow Strip ◽

Stress Strain State ◽

Graphical Environment ◽

Experimental And Theoretical Studies

The article describes a developed technique of a numerical simulation of the stress-strain state of complex-reinforced elements, which allows you to create models of double-span continuous. The performed experimental and theoretical studies allowed us to carry out the testing of the developed design model and to justify the reliability of the proposed numerical simulation methodology. The results of the experimental studies were compared with those of the theoretical studies. The theoretical calculus algorithm was developed by using the finite element method. Theoretical calculations were performed by using the mathematical-graphical environment software system LIRA-SOFT and the mathematical and computer program MATLAB. On the basis of the experimental research, the iso-fields of displacements and stresses in the materials of an eccentrically compressed beam with a small bend of the slab were constructed, which collapse behind the inclined narrow strip of concrete and displacements and stresses in the materials of the eccentrically stretched beam, which is destroyed due to the yield of the upper mounting armature.

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Graph-Analytical Estimation Method of Natural Ventilation Efficiency during Natural Gas Combustion

Materials Science Forum ◽

10.4028/www.scientific.net/msf.931.901 ◽

2018 ◽

Vol 931 ◽

pp. 901-904 ◽

Cited By ~ 1

Author(s):

Victor I. Chebotarev ◽

Anastasia P. Pirozhnikova ◽

Alla V. Koroleva

Keyword(s):

Natural Gas ◽

Natural Ventilation ◽

Theoretical Calculations ◽

Residential Buildings ◽

Experimental Studies ◽

Estimation Method ◽

Combustion Products ◽

Gas Combustion ◽

Analytical Estimation ◽

Ventilation Duct

Open burning of natural gas when using gas equipment in the premises of residential buildings is considered, taking into account the formation of combustion products, depending on the coefficients of excess air. Theoretical and experimental studies of combustion processes are presented. To determine the aerodynamic process in the ventilation duct, theoretical calculations of the dependence of the discharge at the entrance to the ventilation duct from the outside temperature of the atmospheric air were made. Graph-analytic method of evaluating the effectiveness of natural ventilation is carried out.

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Multilayered stable 2D nano-sheets of Ti2NTx MXene: synthesis, characterization, and anticancer activity

Journal of Nanobiotechnology ◽

10.1186/s12951-019-0545-4 ◽

2019 ◽

Vol 17 (1) ◽

Cited By ~ 10

Author(s):

A. Szuplewska ◽

A. Rozmysłowska-Wojciechowska ◽

S. Poźniak ◽

T. Wojciechowski ◽

M. Birowska ◽

...

Keyword(s):

Biological Activity ◽

Mammary Epithelial Cells ◽

Theoretical Calculations ◽

Experimental Studies ◽

Reactive Oxygen ◽

Decisive Role ◽

Max Phase ◽

Mechanisms Of Toxicity ◽

Biological Studies

Abstract Background The biological activity of MXenes has been studied for several years because of their potential biomedical applications; however, investigations have so far been limited to 2D titanium carbides. Although monolayered Ti2NTx MXene has been expected to have biological activity, experimental studies revealed significant difficulties due to obstacles to its synthesis, its low stability and its susceptibility to oxidation and decomposition. Results In this paper, we report our theoretical calculations showing the higher likelihood of forming multilayered Ti2NTx structures during the preparation process in comparison to single-layered structures. As a result of our experimental work, we successfully synthesized multilayered Ti2NTx MXene that was suitable for biological studies by the etching of the Ti2AlN MAX phase and further delamination. The biocompatibility of Ti2NTx MXene was evaluated in vitro towards human skin malignant melanoma cells, human immortalized keratinocytes, human breast cancer cells, and normal human mammary epithelial cells. Additionally, the potential mode of action of 2D Ti2NTx was investigated using reactive oxygen tests as well as SEM observations. Our results indicated that multilayered 2D sheets of Ti2NTx showed higher toxicity towards cancerous cell lines in comparison to normal ones. The decrease in cell viabilities was dose-dependent. The generation of reactive oxygen species as well as the internalization of the 2D sheets play a decisive role in the mechanisms of toxicity. Conclusions We have shown that 2D Ti2NTx in the form of multilayered nanoflakes exhibits fair stability and can be used for in vitro studies. These results show promise for its future applications in biotechnology and nanomedicine.

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Modeling the mechanical wear of the contact elements of pantograph during high-speed movement

E3S Web of Conferences ◽

10.1051/e3sconf/202015701022 ◽

2020 ◽

Vol 157 ◽

pp. 01022

Author(s):

Victor Philippov ◽

Alexandr Smerdin

Keyword(s):

Service Life ◽

High Speed ◽

Theoretical Calculations ◽

Experimental Studies ◽

Maximum Error ◽

Life Assessment ◽

Rolling Stock ◽

Mechanical Wear ◽

Wear Process ◽

Mechanical Component

The use of contact elements with an extended service life is one of the most economical and least costly ways to ensure reliable, economical and environmentally friendly transmission of electricity to rolling stock. To evaluate the service life in OSTU, a methodology for conducting experimental studies of contact pairs of pantograph has been developed and successfully tested, involving bench tests for each pair of contact materials “contact insert - contact wire” in order to determine their optimal combination to reduce wear and increase service life. Assessment of the amount of wear and prediction of the life of the contact elements are made, including using mathematical modeling. The purpose of this article is to improve the mechanical component of the wear model of the contact elements of pantograph in high-speed conditions. The results of experimental studies and theoretical calculations of the mechanical wear of contact elements are presented. The analysis of the graphs allows us to conclude that it is possible to use an improved mathematical model for modeling the mechanical component of the wear process of the elements of contact pairs with a maximum error value of not more than 5%.

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