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The novel inoborate Ni[B2O2(OH)4] was synthesized under high‐pressure/high‐temperature conditions of 9 GPa and 800 °C. Its structure was determined via single‐crystal X‐ray diffraction analysis. The single‐grain IR‐spectrum of Ni[B2O2(OH)4] supports the existence of O−H bonds. The structural similarities and differences with the mineral vimsite, possessing the sum formula Ca[B2O2(OH)4], as well as with the phylloborate HP−Ni(B2O4) is discussed. The title compound can be described as the structural hydrolysis product of the latter. [ABSTRACT FROM AUTHOR]

The novel inoborate Ni[B2O2(OH)4] was synthesized under high‐pressure/high‐temperature conditions of 9 GPa and 800 °C. Its structure was determined via single‐crystal X‐ray diffraction analysis. The single‐grain IR‐spectrum of Ni[B2O2(OH)4] supports the existence of O−H bonds. The structural similarities and differences with the mineral vimsite, possessing the sum formula Ca[B2O2(OH)4], as well as with the phylloborate HP−Ni(B2O4) is discussed. The title compound can be described as the structural hydrolysis product of the latter. [ABSTRACT FROM AUTHOR]

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In this article, the polymerization reaction of elemental sulfur with organic modifiers is studied, and the optimal conditions of the modification process are presented. Also, the process of obtaining polymer sulfur concrete from modified sulfur is presented. Initially, elemental sulfur is heated to a temperature of 140-145 0C, aniline hydrochloride is added, and the temperature of the reaction is raised to 160 0C for 45 minutes. The average density of this obtained sulfur concrete sample was 2382 kg/m3. Sulfur-based concrete was obtained using the modified sulfur obtained in this process. Sulfur-based concrete was obtained by taking 56% sand, 14% ash, and 30% modified sulfur. Physico-chemical properties of sulfur concrete obtained based on modified sulfur and modified sulfur were studied and analyzed using X-ray phase analysis, IR-spectroscopy, scanning electron microscope, gamma-spectroscopy, and X-ray analysis. Also, the thermal analysis of modified sulfur-based concrete was studied using differential-thermal and thermogravimetric analysis. It was calculated that the average particle size d(nm) of the obtained polymer sulfur concrete is equal to 84.14 according to the Debaya-Sherrera equation. [ABSTRACT FROM AUTHOR]

Today a lot of attention is paid to the formation of thermosensitive systems for biomedical and industrial applications. The development of new methods for synthesis of such systems is a dynamically developing direction in chemistry and materials science. In this regard, this paper presents results of the studies of a new synthesized supramolecular polymer system based on polyethylene glycol and tetrafluoroethylene telomers. The films formed from the polymer substance have the property of switching wettability depending on temperature after heating activation. It has been established that the wettability changes at 60 °C. The contact angle of activated hydrophobic polymer film reaches 143°. Additionally, the system exhibits its properties regardless of the pH of the environment. Based on data obtained by the methods of infrared and x-ray photoelectron spectroscopy, differential thermal analysis and thermal analysis in conjunction with wettability and morphology, a model of the behavior of molecules in a polymer system was built that ensures switching of the hydrophilic/hydrophobic surface state. The resulting polymer system, as well as films based on it, can be used in targeted drug delivery, implantation surgery, as sensors, etc. [ABSTRACT FROM AUTHOR]

Pectin, a naturally occurring heteropolysaccharide, has in recent years grown increasingly in importance. In this present study, white pumpkin or bottle gourd was chosen as a representative of the Cucurbitaceae family to extract powder pectin. At initial and final times, treatment (T1) and treatment (T2), the amount of pectin in calcium pectate in fresh pumpkin ranges from 3.7% to 5.8%. Standardized water bath heating was used to extract pectin from white pumpkins by boiling the fruit at atmospheric pressure for five minutes at 95 oC. Distilled water was also tested for pectin isolation from white pumpkins as an extraction solvent. The weight increased by 844.98% at T1 and decreased to 675.67% at T6, following which was precipitation with 95% ethanol yielding maximum on the above during the extraction of pectin by water bath at varied period durations. Finally, the degree of esterification was the rate 68.76% at T1 to 59.87% at T6, with the methoxyl content having a value 9.45% at T1 to 6.82% at T6 and the anhydrouronic acid content (AUA%) being 76.66% at T1 to 64.77% at T6. Moisture, equivalent weight, degree of esterification, and methoxyl concentration all reduced as extraction time increased. However, many indicators, like ash content, acetyl value, and jelly grade, exhibited an early rise in value that later declined as extraction time increased. Thus, the optimal method for pectin isolation involves boiling the pumpkin in water at atmospheric pressure for 5 to 30 minutes. In addition, among different times of extraction pectin that was obtained from 30 minutes had the highest lightness 82.07 while the lowest redness 2.03 and yellowness 5.14 of pectin was recorded at this time. This pectin met the criteria for food additive use, indicating its potential as a commercially viable alternative source.

Two express methods are presented in this paper. The first method is a high-resolution gamma-spectroscopic method based on a germanium detector, the second method is an IR-spectroscopic method. The applied complex of methods allows to determine the sources of uranium and thorium, identify the rhythms of uranium accumulation associated with regional events; identify areas with a high content of uranium due to the influence of local sources (faults, hydrothermal, etc.); determine the amount of authigenous uranium in the composition of total uranium; determine thermal maturity of organic matter in shales without their preliminary demineralization. To identify levels of increased uranium intensity in the high-carbon strata, a set of indicators has been proposed, which includes both applied indicators in practice of geological work and new indicators.New indicators have been tested on the collection of shale reference samples. For them, values were established that characterize the processes of uranium accumulation and uranium removal. On the example of Ukhta Region according to the proposed indicators, the sections from the VendianRiphean to Domanic inclusive were interpreted.The performed work showed the possibility of comparing the calculated gamma-spectroscopic data with the data of other methods. This opens up a broader perspective for the use of express non-destructive gamma-spectroscopic method for detecting levels with a high content of uranium in the shale rocks, to which ore-bearing concentrations of a number of metals are also confined.

The key features of the interaction between peridotites of the continental lithospheric mantle and reduced hydrocarbon-rich fluids have been studied in experiments conducted at 5.5 GPa and 1200 °C. Under this interaction, the original harzburgite undergoes recrystallization while the composition of the fluid changes from CH4-H2O to H2O-rich with a small amount of CO2. The oxygen fugacity in the experiments varied from the iron-wustite (IW) to enstatite-magnesite-olivine-graphite/diamond (EMOG) buffers. Olivines recrystallized in the interaction between harzburgite and a fluid generated by the decomposition of stearic acid contain inclusions composed of graphite and methane with traces of ethane and hydrogen. The water content of such olivines slightly exceeds that of the original harzburgite. Redox metasomatism, which involves the oxidation of hydrocarbons in the fluid by reaction with magnesite-bearing peridotite, leads to the appearance of additional OH absorption bands in the infrared spectra of olivines. The water content of olivine in this case increases by approximately two times, reaching 160–180 wt. ppm. When hydrocarbons are oxidized by interaction with hematite-bearing peridotite, olivine captures Ca-Mg-Fe carbonates, which are products of carbonate melt quenching. This oxidative metasomatism is characterized by the appearance of specific OH absorption bands and a significant increase in the total water content in olivine of up to 500–600 wt. ppm. These findings contribute to the development of criteria for reconstructing metasomatic transformations in mantle rocks based on the infrared spectra and water content of olivines. [ABSTRACT FROM AUTHOR]

The new zinc borate Zn6.1B6O19H7.8 was synthesized via a high‐pressure/high‐temperature multianvil approach at 10 GPa and 1573 K. The structure of the non‐centrosymmetric compound was investigated by single‐crystal X‐ray diffraction measurements, exhibiting (BO4), (ZnO5), and (ZnO6) units including a distinct disorder on a part of the zinc and boron sites. The IR spectroscopic data on the bulk material confirm the presence of hydroxyl groups in this new borate. [ABSTRACT FROM AUTHOR]

The new zinc borate Zn6.1B6O19H7.8 was synthesized via a high‐pressure/high‐temperature multianvil approach at 10 GPa and 1573 K. The structure of the non‐centrosymmetric compound was investigated by single‐crystal X‐ray diffraction measurements, exhibiting (BO4), (ZnO5), and (ZnO6) units including a distinct disorder on a part of the zinc and boron sites. The IR spectroscopic data on the bulk material confirm the presence of hydroxyl groups in this new borate. [ABSTRACT FROM AUTHOR]

A comparative study of the processes of metal-stimulated formation of silicon nanocrystals in SiOx–Sm structures was carried out. Samples with identical oxide matrix stoichiometry and Sm impurity content were formed using two methods: layer-by-layer deposition and coevaporation of SiO and Sm. Studies of PL and IR absorption spectra found that the admixture of samarium in samples of both types accelerates the thermally stimulated decomposition of samarium-doped SiOx films into Si and SiO2 and reduces the transition temperature of silicon nanoparticles from an amorphous state to a crystalline state. However, in (SiOx/Sm)10 multilayers, this effect is more pronounced than in single-layer films obtained using the co-evaporation method. Studying the Raman spectra of (SiOx/Sm)10 multilayers annealed at 750 °C determined that the relative volume fraction of nanocrystals in the silicon phase of the sample is ~ 38%. No line corresponding to the crystalline nc-Si was observed in the Raman spectra of samples deposited by co-evaporation and annealed under the same conditions. For these samples, a narrow line in the Raman spectrum corresponding to crystalline nc-Si appears only after annealing at 970 °C. In this case, the relative fraction of Si nanocrystals in the silicon phase of the sample was ~ 17%, 2.2 times less than for a similar multilayer annealed at 750 °C. This also indicates that, in multilayer (SiOx/Sm)10 samples, the thermally stimulated decomposition of SiOx, as well as the formation and crystallization of silicon nanoparticles, occurs at lower temperatures than in similar samples obtained by coevaporation. A possible mechanism for lowering the crystallization temperature of nc-Si in (SiOx/Sm)10 multilayers is discussed. [ABSTRACT FROM AUTHOR]

The purpose of this paper is determination of the effect of rice flour on the conformational transformations in the structure of wheat bread, which contains lecithin, and its quality indicators. In the last decade, inflammatory bowel diseases, which became a global problem in the world, are a serious threat to human health. In the diet therapy of these diseases, it is recommended not to use a large quantity of dietary fiber. Rice flour is a perspective raw material for production of bakery products for people with this disease, as it contains 8.5 times less dietary fiber than premium wheat flour. Analysis of the chemical composition of bread without rice flour and with its addition showed a slight decrease in protein content by 4.4-10.5%, depending on the dosage (10-40% of wheat flour replacement), and fiber content – by 8.7-35.5%. It was confirmed that conformational changes occur in the structure of proteins and other nutrients of the product in bread making process. The changes of structural groups and their redistribution in the dough after kneading at once and after 3.5 hours of its fermentation and in bread when part of the wheat flour is replaced with rice flour were analyzed. The utilitarian coefficient, redundancy coefficient, DKAS and the indicator of biological value indicated that it is rational to make a replacement of wheat flour with 10% or 20% of rice flour.

Double phosphates compounds may possess catalytic, magnetic, electrophysical, non-linear optical properties and are used as monocrystals or polycrystals, ceramics etc. The tailor-made synthesis of double phosphates of alkali and multivalent metals is the basis for the in-depth research and investigation of physical and chemical properties, composition and structure of the compounds to be used for the development of new materials for multi-purpose use. Episodic syntheses of compounds MI 3MIІ MIV(PO4)3, MI 2MIIMIV(P2O7)2, MI 2MII(PO3)4 and МІ MІІ 4(РО4)3 3 (where МI – Li, Na, K; МIІ – Mn, Co, Ni; MIV – Zr), were made from various starting materials by the sintering method. After all, the selection of compounds for the synthesis of compounds of this type is a rather difficult task, often impossible. A systematic approach to the selection of starting reagents, temperature regime, interaction time between components are factors that can be adjusted and operated to achieve the target. The work used the method of solid-phase synthesis, after working out the synthesis method on the “model” Na2NiZr(P2O7)2. The synthesis was carried out starting from Na2CO3, NiO, CoO, ZrO2, ammonium hydro- and dihydrogen phosphate. The synthesis of compounds was carried out based on preliminary derivatographic studies of the passage of processes according to the corresponding reaction schemes. Completeness of synthesis stages was monitored at all stages using physico-chemical research methods. The DTA method confirmed the possibility of solid-phase synthesis of complex phosphate compounds that contain several transition metals – MI Ni2MIV(PO4)3 (where МI – Li, Na, K; MIV – Ti, Zr, Sn). The optimal temperature conditions for obtaining a number of phosphate compounds based on various starting substances for their synthesis have been found. The synthesized compounds were investigated by X-ray diffraction, DTA and IR spectroscopy, and their complete chemical analysis was carried out. The influence of a number of factors on the conditions of production of phosphate compounds of the MI Ni2MIV(PO4)3 (where МI – Li, Na, K; MIV – Ti, Zr, Sn) has been found. It can be assumed that the ionic conductivity in the synthesized compounds is of the “NASICON” type, and therefore the synthesized substances can be used as functional materials with valuable electro-physical properties. [ABSTRACT FROM AUTHOR]

The effect of Sm on thermally stimulated decomposition of SiOx and the formation of silicon nanocrystals during high-temperature air annealing was studied by measuring the spectra of photoluminescence (PL), infrared (IR) reflection and transmission and Micro-Raman scattering (RS). The SiOx: Sm films were produced by thermal co-evaporation of silicon monoxide and metallic samarium powders in a vacuum onto polished c-Si and silica substrates. The Sm concentration varied from 0.8 to 2.0 wt. %. In the SiOx: Sm films annealed at 970 ºC, an intense PL band of silicon nanocrystals was found in the 850–900 nm region, the position and intensity of which depend on the samarium concentration. The formation of Si nanocrystals in those films is also confirmed by studying their Raman spectra. At the same time, no Si nanocrystals were found in undoped SiOx films annealed under similar conditions. The analysis of these spectra made it possible to determine the sizes of silicon nanocrystals: 3.7 nm from the PL spectra and 3.6 nm from the Raman spectra. A possible mechanism of thermally stimulated interaction of Sm atoms with the SiOx matrix is discussed. [ABSTRACT FROM AUTHOR]

Photooxidation processes during irradiation of the aerosil-filled polyurethane films, based on oligooxypropylene glycol, toluene diisocyanate and trimethylolpropane, for a use as the active media of solid-state lasers were investigated by means of the IR-spectroscopy and dynamic mechanical analysis (DMA) methods, depending on the inorganic dopant concentration (5 and 7 wt%). The IR-spectroscopic experiments showed that the introduction of aerosil slowed down these processes. Data from dynamic mechanical studies indicated that irradiation of aerosil-filled polyurethane matrices caused an increase in its structural heterogeneity and a drop of the elastic modulus. During irradiation of the polyurethane material with 7 wt% of aerosil, a partial destruction of the nanofiller spatial network was possible due to dispersion of the irradiation energy by the nanoparticles. The obtained results demonstrated a positive effect of the aerosil nanofiller on the polyurethane material stability under irradiation with an ultra-high pressure mercury lamp.

A new complex [Dy(C5H7O2)3(C5H5NO)]2·2CHCl3 (1) has been synthesized by the reaction of pyridine-N-oxide with dysprosium (III) acetylacetonate in an n-heptane/chloroform mixture (1/20). X-ray data show that each dysprosium atom is chelate-like coordinated by three acetylacetonate ligands and the oxygen atom from two bridging molecules of pyridine-N-oxide, which unite the dysprosium atoms into a binuclear complex. Static (constant current) and dynamic (alternating current) investigations and ab initio calculations of the magnetic properties of complex 1 were performed. The complex was shown to exhibit a frequency maximum under alternating current. At temperatures above 10 K, the maximum shifts to a higher frequency, which is characteristic of SMM behavior. It is established that the dependence of ln(τ) on 1/T for the relaxation process is nonlinear, which indicates the presence of Raman relaxation mechanisms, along with the Orbach mechanism. [ABSTRACT FROM AUTHOR]

The extraction of Li, Na and K trichloroacetates with B15C5 and tPB15C5 in chloroform has been studied. The compounds of lithium, sodium and potassium trichloroacetates with B15C5 in crystalline form were isolated and characterized by X-ray diffraction and IR spectroscopy techniques. A significant transition of B15C5 into the equilibrium aqueous phase was established. It is shown that the use of its lipophilic analog helps to avoid this problem and leads to a significant increase in lithium extraction. [Display omitted] The extraction of Li, Na and K trichloroacetates by benzo-15-crown-5 ether and its lipophilic analog in chloroform has been studied. Extraction isotherms were obtained and the transition of extractants into the equilibrium aqueous phase was determined. The metal: crown ether ratios in the extracted compounds were determined by the slope analysis method. The thermodynamic extraction parameters of Li, Na and K trichloroacetates in systems with benzo-15-crown-5 ether (B15C5) and 3- tert -pentylbenzo-15-crown-5 ether (tPB15C5) were determined. The complexes [Li 3 (B15C5)(TCA) 3 ], [Na(B15C5)(TCA)] and [K(B15C5) 2 ](DCA)·H 2 O were isolated in crystalline form and characterized by IR spectroscopy and X-ray diffraction. [ABSTRACT FROM AUTHOR]

Currently, diamonds are widely used in science and technology. However, the properties of diamonds due to their defects are not fully understood. In addition to optical methods, positron annihilation spectroscopy (PAS) can be successfully used to study defects in diamonds. Positrons are capable of detecting vacancies, and small and large clusters of vacancies induced by irradiation, by providing information about their size, concentration, and chemical environment. By mapping in the infrared (IR) range, it is possible to consider the admixture composition of the main inclusions of the whole plate. This article presents the results of a study of defects in synthetic diamond plates, one of which was irradiated by electrons. It presents data about the distribution of the defect concentration obtained by Infrared spectroscopy. PAS with a monochromatic positron beam can be used as a non-destructive technique of detecting defects (vacancy) distribution over the depth of diamond plates. [ABSTRACT FROM AUTHOR]

The purpose of this paper is determination of the effect of rice flour on the conformational transformations in the structure of wheat bread, which contains lecithin, and its quality indicators. In the last decade, inflammatory bowel diseases, which became a global problem in the world, are a serious threat to human health. In the diet therapy of these diseases, it is recommended not to use a large quantity of dietary fiber. Rice flour is a perspective raw material for production of bakery products for people with this disease, as it contains 8.5 times less dietary fiber than premium wheat flour. Analysis of the chemical composition of bread without rice flour and with its addition showed a slight decrease in protein content by 4.4-10.5%, depending on the dosage (10-40% of wheat flour replacement), and fiber content - by 8.7-35.5%. It was confirmed that conformational changes occur in the structure of proteins and other nutrients of the product in bread making process. The changes of structural groups and their redistribution in the dough after kneading at once and after 3.5 hours of its fermentation and in bread when part of the wheat flour is replaced with rice flour were analyzed. The utilitarian coefficient, redundancy coefficient, DKAS and the indicator of biological value indicated that it is rational to make a replacement of wheat flour with 10% or 20% of rice flour. [ABSTRACT FROM AUTHOR]

A study was carried out in order to identify the aspects of geochemical processes occurring during the formation of green and light-blue amazonite crystals. Green, light-blue and greenish-blue amazonites from rare-metals deposits of Ukraine (Perzhanske, Ukrainian Shield), rf (Gora Parusna, Ploskogirske, Kola Peninsula; Orlovske, Western Transbaikalia), and USA (Rutherford, Virginia) were investigated using X-ray luminescence (XRL), infrared (IR) spectroscopy and X-ray diffraction. The rock-forming microcline from the Perzhanske, Orlovske and Katuginske (rf) deposits was also studied. It was found that the multi-colored crystals of amazonite have similar degrees of Si/Al ordering. They are represented by the maximum microcline with 2t1 = 0.959—1.0. The various samples only differ significantly in their lead contents that range between 2000 and 10000 ppm in green amazonite and 200 ppm in light-blue colored crystals. Differences between untreated crystals and those annealed in air (1173 K) or under a stream of He (923 K) samples were observed in terms of the composition, ratio of optically active centers and oxygen- hydrogen defects. Their composition and concentration in the untreated natural crystals reflect the genesis conditions of parent rocks, and, first of all, the redox and fO2 conditions of water-containing fluids, which affect the isomorphism of plumbum in the structures of the green and light-blue crystals, mechanisms of crystal chemical compensation of Pb2+ ions and correlates with different degree of ferum oxidation (Fe3+ → Fe2+). Changes in redox and fO2 parameters of the mineral-forming fluid are the most important factors affecting the activity and acid-base properties in the residual water fluids, the process of reduction following 2H2O + 2e– → H2 + 2OH– or oxidation via 2H2O – 4e– → O2 + 4H+. A complex combination of these factors allows the formation of certain nanosized defects in the structures of the amazonite crystals. These include impurity ([Pb2+ – Pb+]3+)and impurity-vacancy (Pb2+ – VK) clusters that serve as chromophore centers for green and light-blue color, respectively. [ABSTRACT FROM AUTHOR]

Pomegranate seed and peel powders are suitable for the production of pectin, oil, proteins and as biologically active additives for food enrichment. Knowledge of the chemical composition and thermal changes of powders allows to control the technological regimes, yield and quality of the final product. As a result of the studies, the chemical composition and thermal properties of a finely dispersed pomegranate peel and seed powder subjected to heat treatment by X-ray diffractometry, IR-, EPR spectroscopy and thermal analysis (TG/DTG/DSC) have been carried out. X-ray diffractometry showed that the crystal structures present in the original samples, when heated in air at 110 °C for 30 min. are destroyed and in all cases the samples pass into the amorphous state, a noticeable difference is found in the position and intensity of the observed bands in the spectra in the initial and heat-treated samples. IR spectroscopy data show that drying the samples at 105 °C in air for 30 min leads to a significant change in the chemical composition of the powders. EPR spectroscopy showed the presence of paramagnetism in the samples and identified organic radicals and paramagnetic centers from Fe3+ ions. The features of the change in the chemical composition during drying of samples, which are characteristic of drying processes, namely, are the result by dehydration, dehydroxylation and denaturation of protein compounds that make up this process, have been established. Temperature intervals (54.2-147.9 and 71.7-95.4 °C, 147.9-343.7 and 343.7-466 °C) associated with changes in the composition of organic compounds, contained in the powders were determined. [ABSTRACT FROM AUTHOR]

FTIR spectral analysis of solvation effects on the frequencies of O–H stretching vibrations of methanol complexes with linear (diethyl ether, di-n-butyl ether, and diglyme) and cyclic ethers (1,4-dioxane, 12-crown-4, 15-crown-5, and 18-crown-6) was carried out. The comparative analysis of the influence of solvation effects on the frequencies of O–H groups of methanol in aprotic solvents for both free and bound molecules with ethers (B) had been performed. Complexes in proton-donor solvents as well as in chloroform were investigated to quantify the change in the strength of X–H···B (where X = O) hydrogen bonds due to cooperative interactions. The influences of structure and size of the ether cycle on the contribution of the cooperativity effect of methanol with ethers are discussed. [ABSTRACT FROM AUTHOR]

Graptolite–argillites (black shales) are studied as potential source of different metals. In the processing technologies of graptolite–argillites, a preceding thermal treatment is often applied. In this study, the thermal behavior of Estonian graptolite–argillite (GA) samples from Toolse, Sillamäe and Pakri areas were studied using a Setaram Labsys Evo 1600 thermoanalyzer coupled with the Pfeiffer OmniStar Mass Spectrometer. The products of thermal treatment were studied by XRD, FTIR, and SEM analytical methods. The experiments were carried out under non-isothermal conditions of up to 1200 °C at different heating rates in the atmosphere containing 79% Ar and 21% O2. The differential isoconversional Friedman method was applied for calculating the kinetic parameters. All studied GA samples are characterized with high content of orthoclase (between 38.0 and 57.3%) and quartz (between 23.8 and 35.5%), and with lower content of muscovite, jarosite, pyrite, etc. The content of organic carbon in GA samples studied varied between 7.3 and 14.2%. The results indicated that, up to 200 °C, the emission of hygroscopic and physically bound water takes place. Between 200 °C and 500–550 °C, this is followed by thermo-oxidative decomposition of organic matter. The first step of thermo-oxidation of pyrite with the emission of water, carbon and sulphur dioxide, nitrogen oxides, and different hydrocarbon fragments indicated the complicated composition of organic matter. At higher temperatures, between 550 °C and 900 °C, the transformations continued by dehydroxylation processes in clay minerals, and the decomposition of jarosite and carbonates took place. At temperatures above 1000–1050 °C, a slow increase in the emission of sulphur dioxide followed, indicating the beginning of the second step of thermo-oxidative decomposition of pyrite, which was not completed for temperatures of up to 1000 °C. Kinetic calculations prove the complicated mechanism of thermal decomposition of GA samples: for Pakri GA samples, it occurs in two steps, and for Silllamäe and Toolse GA samples, it occurs in three steps. Preliminary tests for the estimation of the influence of pre-roasting of GA samples on the solubility of different elements contained in GA at the following leaching in sulphuric acid is based on Toolse GA sample. [ABSTRACT FROM AUTHOR]

The results of the synthesis of lanthanum borate glasses modified with highly polarizable cations (Nb, Ti, Zr, Ta) are described, their crystallization properties were studied, and their structural features were investigated by means of IR spectroscopy. It was determined that glass blanks with refractive index > 1.8 can be obtained in the composition range 25La2O3–xMnOm–(75 – x)B2O3 (M = Nb, Ta, Ti, Zr, x = 5 – 25 mol.%). It is proposed that a network of large polyhedra of the modifying cation, which are bound at the vertices, is formed in addition to the borate network, thereby allowing the melt to retain its glass-forming ability. [ABSTRACT FROM AUTHOR]

The tomato (Solanum lycopersicum Linnaeus) is one of the most important vegetable crops in the world. Still, there are phytopathogenic bacteria that cause a decrease in the yield or can kill the plant, like Pseudomonas syringae pv. tomato (Pst), Xanthomonas vesicatoria (Xv), Clavibacter michiganensis subsp. michiganensis (Cmm), Ralstonia solanacearum (Rs ) and Agrobacterium tumefeciens (At). Synthetic chemical fungicides are primarily used to control plant pathogenic bacteria, but their rapid growth makes them resistant to control. This research work is aimed at assessing the in vitro antibacterial activity of the ethanolic extract of Magnolia tamaulipana Vazquez leaves against Rs, Pst, Xv, Cmm, and At, as well as obtaining information about this plant species' chemical composition. The extract inhibited the growth of the five phytopathogenic bacteria that were tested. The growth inhibition rate ranged between 8.22 and 100%. The inhibitory concentration, IC50(90), required to inhibit 50 (90%) of Pst, Xv, Cmm, and At bacterial growth, was 34.71 (39.62), 23.09 (441.88), 64.75 (176.73) and 97.72 (535.48) ppm, respectively. The phytochemical analysis detected the presence of phenols, tannins, terpenes, saponins. M. tamaulipana ethanolic extract has antimicrobial properties and it must be considered a new control agent.

Introduction. This review describes the physicochemical properties that determine the use of hyaluronic acid in ophthalmology. We have studied methods for determining hyaluronic acid using various analytical methods.Text. Hyaluronic acid is a high molecular weight glycosaminoglycan that consists of repeating disaccharides of N-acetylglucosamine and D-glucuronic acid. Carboxyl, hydroxyl and acetoamide groups give hydrophilic properties to the molecule of this anionic heteropolysaccharide. Depending on how the hyaluronic acid is obtained, its molecular weight varies over a wide range. Researchers developed methods for controlling hyaluronic acid, which include the turbidimetric titration method, the method of high-performance capillary electrophoresis and high-performance liquid chromatography and IR spectroscopic method.Conclusion. Due to its properties, hyaluronic acid is widely used as an active ingredient in pharmaceutical preparations. Today, there are a number of methods for the determination of hyaluronic acid, including the method of turbidimetric titration, the method of capillary electrophoresis. High performance liquid chromatography (HPLC) and IR spectroscopy methods are presented in the Japanese Pharmacopoeia and the European Pharmacopoeia. These techniques are widely used due to their high reproducibility, accuracy, and relative simplicity.

Objectives. This study evaluates the effect of the modification process on the group composition of bitumen and bitumen binders containing rubber powder and hybrid modifier that is based on styrene–butadiene thermoplastic elastomer and rubber crumb. The aim of the study was to determine the presence or absence of functional groups that reflect the direction of physicochemical processes during the preparation of a hybrid modifier in rotary dispersers and during the modification of bitumen binders. Methods. Rubber powder and hybrid modifier were obtained by high-temperature shear grinding using a rotary disperser. Bitumen and modified bitumen binders were investigated via Fouriertransform infrared spectroscopy. Using the method of spectral subtraction, it was determined that during the process of manufacturing modified bitumen binders, structural changes occur in both bitumen and modifiers. During this study, the extraction of modifiers (rubber powder and hybrid modifier) in toluene was performed. Results. The quantitative analysis of changes in the group composition of modifiers before and after the modification procedure was carried out. The active polymer and structural indices were determined. The general trend of the change in the active polymer and structural indices was noted for the initial spectra of the rubber powder and hybrid modifier, and their spectra were obtained after the procedure of subtraction from the spectra of bitumen binders. Conclusions. The interdiffusion of aromatic compounds between the bitumen component and modifier particles was confirmed. On the basis of the results of the extraction of modifiers in toluene, and by taking into account the infrared spectroscopy data, it was determined that during the production of hybrid modifier during the simultaneous grinding of rubber crumb and styrene– butadiene thermoplastic elastomer, there was a chemical interaction between them.

A new complex [Dy(C5H7O2)3(C5H5NO)]2·2CHCl3 (1) has been synthesized by the reaction of pyridine-N-oxide with dysprosium (III) acetylacetonate in an n-heptane/chloroform mixture (1/20). X-ray data show that each dysprosium atom is chelate-like coordinated by three acetylacetonate ligands and the oxygen atom from two bridging molecules of pyridine-N-oxide, which unite the dysprosium atoms into a binuclear complex. Static (constant current) and dynamic (alternating current) investigations and ab initio calculations of the magnetic properties of complex 1 were performed. The complex was shown to exhibit a frequency maximum under alternating current. At temperatures above 10 K, the maximum shifts to a higher frequency, which is characteristic of SMM behavior. It is established that the dependence of ln(τ) on 1/T for the relaxation process is nonlinear, which indicates the presence of Raman relaxation mechanisms, along with the Orbach mechanism.

In the present work, the arsenate [As(V)] adsorption by loam and sandy loam soil was carried out as a function of initial As(V) concentration, pH, contact time, and adsorbent dose to ensure As adsorption and its mobilization in the soil of arsenic-affected areas. The As(V) adsorption with varying time and initial As(V) concentrations were analyzed using the linear and nonlinear forms of the adsorption isotherms and kinetic models. Based on the comparison of R2 values and calculated qe values, the linear pseudo-second order and non-linear pseudo-first order and second-order kinetics showed better applicability of S1 (loam) than S2 (sandy loam) soil samples for arsenate adsorption. The loam soil (S1) also exhibited maximum adsorption capacity and low As(V) mobility due to the presence of soil organic matter and low phosphorus content. The FTIR results showed that soil surface functional groups (─COOH, O─H and Fe─O group) were predominantly involved in As(V) binding via surface complexation or coordination. Results derived from equilibrium adsorption isotherms showed that the data fitted well to both the linear and non-linear Langmuir adsorption isotherms. The monolayer surface adsorption (qmax) in S1 sample (29.41 µg/g) was better than that in the S2 soil (27.39 µg/g), indicating strong surface affinity of S1 toward As(V) than S2 soil sample. This observation was also supported by the separation factor (RL values). Results on thermodynamic parameters (ΔH°, ΔS° and ΔG°) showed spontaneous and endothermic nature of adsorption. The activation energy (Ea) calculated for the surface binding of As(V) onto S1 (4.56 kJ mol–1) and S2 soil (7.15 kJ mol–1) indicated that the surface binding of As(V) by both the soils was an energetically favorable physico-chemisorption. The results on adsorption characteristics of both soil samples indicated that adsorption efficiency and retention ability of loam soil (S1) was better than sandy loam (S2) soil. [ABSTRACT FROM AUTHOR]

Single crystals of Na2Mn3(P2O7)2 compound have been first obtained during the examination of interaction in the Na2O-P2O5-Mn2O3-NaF (10 wt.%.) system in the fluxes with Na2O:P2O5 molar ratios ranging from 0.52 to 0.76 (saturated with manganese(III) oxide 25.0-32.0 wt.%) at the temperatures of 960-880°C. Optimum conditions for the synthesis and growing of single crystals of Na2Mn3(P2O7)2 compound have been determined. Complete X-ray diffraction analysis of the synthesized phosphate Na2Mn3(P2O7)2 has been performed. According to its structure, the double phosphate Na2Mn3(P2O7)2 belongs to the triclinic crystal system, spatial grid P1; lattice parameters are as follows: a=5.359 Å, b=6.563 Å, c=16.299 Å, α=81.29°, β=82.70°, γ=72.44°, V=538.23 ų, Z=4, Ccalc= 3.447 g cm-3. Structural features of synthesized phosphate have been determined. The structure is composed of continuous chain of distorted octahedra [MnO6] spacing along the direction ob. Diphosphate groups of tetrahedra [PO4] divide the chains [MnO6] and also run along ob direction. Pairwise linked pentagonal bipyramids of sodium divide the «units» of polyhedral of manganese and phosphorus, filling the channels along oy axis. The crystalline structure of Na2Mn3(P2O7)2 includes three nonequivalent, according to their crystallography, octahedra of manganese with slightly distorted form. The compound has been studied using X-ray diffraction and X-ray phase analyses, differential thermal analysis, IR spectroscopy and complete chemical analysis. [ABSTRACT FROM AUTHOR]

The present work addresses the problem of stratospheric ozone depletion. While gas phase and photochemically induced reactions of ozone are well studied, the mechanisms of heterogeneous O3 interactions with different halogenated species still remain uncertain. An in situ FTIR investigation of low-temperature heterogeneous reactions of ozone and haloacetic acids in conditions close to stratospheric was performed and supported by ab initio quantum chemical calculations. Products of ozone reaction with differently chlorine and bromine-substituted acetic acids were identified and possible reactions pathways were suggested. Ozone can attach to a carbon atom to release a halogen atom that forms a halogen oxide. Halogen oxide in its turn can take part in the catalytic cycles of ozone depletion. Suggested reaction pathways leading to the additional release of the chlorine oxides can enhance the atmospheric models that calculate ozone concentration. [ABSTRACT FROM AUTHOR]

Copyright of Tribologie und Schmierungstechnik is the property of Narr Francke Attempto Verlag GmbH & Co.KG and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Technisches Messen is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background. The literature data on the synthesis and properties of mixed-metal complexes of 3d metals with ammonium vanadate and 5-amino-2-mercaptobenzimidazole is limited. Thus, the synthesis and study heterometallic compounds allowed elaborating new aspects of coordination chemistry. Purpose. Elaboration of the synthesis method for mixed-metal complexes of Mn (II), Co (II), Ni (II), Cu (II) and Zn nitrates with ammonium vanadate and 5-amino-2-mercaptobenzimidazole (L) and study of their composition and structure with modern physical and chemical methods. Methodology. A technique for synthesis of mixed-metal complex compounds has been elaborated. For their synthesis, an alcoholic solution of the ligand (molar ratio M: M: L=1: 2: 2) was added to solution of ammonium vanadate and metal chlorides, pH 8. The reaction had been carried out at heating for 40 min. The coordinating competitive donor centers, the electronic and geometric structure of the ligand molecule were investigated by quantum-chemical calculations using the DFT / V3LIP / LanL2DZ method in the Gaussian09 software package. The composition and structure of the synthesized mixed-metal complex compounds were investigated by the methods of elemental, thermal analysis and FTIR- spectroscopy. Originality. A procedure has been developed for synthesis of mixed-metal complex compounds: Mn (II), Co (II), Ni (II), Cu (II), Zn nitrates with ammonium vanadate and 5-amino-2-mercaptobenzimidazole. It was found that in complexation reactions the ligand molecule is coordinated through the nitrogen atom with the negative value of the effective partially localized charge. Findings. The data on coordinating competitive donor centers, the electronic and geometric structure of the ligand molecule. [ABSTRACT FROM AUTHOR]

The crystalline complexes CuL2X2 and CuL4X2 , where X = Cl or X = Br were synthesized by the interaction of copper(II) chloride or bromide with 1-tert-butyl-1,2,4-triazole (L) in water or organic solvents. The structure of metal complexes have been studied by elemental analysis, X-ray analysis and IR-spectroscopy in the medium (4000 –500 cm –1 ) and long-wavelength (400–50 cm –1 ) regions. Quantum chemical calculations of the vibrational spectra of the CuL2Cl2 and CuL4Cl2 complexes have been carried out to perform the assignment of the signals in the IR-spectra. It is shown that the polymer structure of CuL2X2 complexes is formed due to bridging of one of their halide ions. In the CuL4X2 complexes, the halide ions and 1-tert-butyl-1,2,4-triazole form an island type structure. In all metal complexes 1-tert-butyl-1,2,4-triazole is coordinated by N(4) atom of heterocycle.

Spectroscopic data, depending on an experimentally controllable variable, contains a wealth of information for researchers. However, complex spectra with overlapping peaks and multiple transitions complicate its straightforward interpretation and often the full contained information cannot be extracted. Here, the Spectram toolbox for MATLAB® and GNU Octave is described which was developed to analyse such data by a method based on singular value decomposition (SVD) and transition model coupled recombination. The method employs user-defined transition models, which depend on the control variable and are often known, or empirical descriptions of the transitions, which often can be guessed, to deconvolute such data. The outcome are the spectral components associated to the transitions and the model parameters. Both can be directly interpreted in terms of their physical meaning. Spectram can be applied to any desired spectroscopic technique and gives full freedom in the choice of the applied models, making it highly reusable. Funding statement: Funding by the European Union’s Horizon 2020 research and innovation program under a Marie Skłodowska-Curie Grant (Agreement No. 705857) is acknowledged.

A sorbent was synthesized by thermal processing of sapropel residue after the extraction of humic acids, and subsequently modified with polyhexamethyleneguanidine and humic acids pre-isolated from sapropel. The humic sorbent transformations have been studied under air at the temperature range of 20-1000°C by thermal analysis. The presence of various functional groups on the surface of a humic sorbent from sapropel has been confirmed by IR-spectroscopy. Sorption of palladium and nickel ions from water solutions was studied. The value of static capacity of the synthesized humic sorbent for palladium was 38.8±2.7, and for nickel ions was 32.0±1.8 mg/g, respectively. It has been established that the equilibrium of sorption was described by the Freundlich isotherm equation.

Thermal behaviour of shelly Estonian phosphorite ores from Iru, Toolse, Ülgase deposits and their concentrates have been studied. The phosphorus-bearing mineral in Estonian phosphate ore is fluorcarbonate apatite (francolite), originated from brachiopod Obolus apollinis shells that makes it different from all other sedimentary phosphate ores. The experiments on a Setaram Labsys Evo 1600 thermoanalyzer coupled with Pfeiffer Omnistar Mass Spectrometer for evolved gases analysis were carried out under non-isothermal condition at the heating rate of 10 °C min−1 up to 1200 °C in an oxidizing and inert atmosphere containing 79% of Ar and 21% of O2 or 100% Ar, respectively. The results obtained indicated the complicated character of transformations occurring at thermal treatment of Estonian phosphorites and certain differences depending on the mineralogical composition of sample and gaseous environment. The changes in francolite structure, probable substitution of sulphur additionally to carbonate, were studied by FTIR and XRD. The oxygen in gaseous atmosphere suppresses the liberation of carbonate and sulphate from the structure of francolite. The character of CO2 and SO2 release at heating depending on the atmosphere composition was explained. The impact of thermal treatment of phosphorite on the P2O5, CaO and SO4−2 solubility in 2% citric acid solution and on the particles pore volume, as well as their dependence on each other, was also studied. [ABSTRACT FROM AUTHOR]

The tomato (Solanum lycopersicum Linnaeus) is one of the most important vegetable crops in the world. Still, there are phytopathogenic bacteria that cause a decrease in the yield or can kill the plant, like Pseudomonas syringae pv. tomato (Pst), Xanthomonas vesicatoria (Xv), Clavibacter michiganensis subsp. michiganensis (Cmm), Ralstonia solanacearum (Rs) and Agrobacterium tumefeciens (At). Synthetic chemical fungicides are primarily used to control plant pathogenic bacteria, but their rapid growth makes them resistant to control. This research work is aimed at assessing the in vitro antibacterial activity of the ethanolic extract of Magnolia tamaulipana Vazquez leaves against Rs, Pst, Xv, Cmm, and At, as well as obtaining information about this plant species' chemical composition. The extract inhibited the growth of the five phytopathogenic bacteria that were tested. The growth inhibition rate ranged between 8.22 and 100%. The inhibitory concentration, IC50(90), required to inhibit 50 (90%) of Pst, Xv, Cmm, and At bacterial growth, was 34.71 (39.62), 23.09 (441.88), 64.75 (176.73) and 97.72 (535.48) ppm, respectively. The phytochemical analysis detected the presence of phenols, tannins, terpenes, saponins. M. tamaulipana ethanolic extract has antimicrobial properties and it must be considered a new control agent. [ABSTRACT FROM AUTHOR]

A review of recent results and new data on the study of the optical response from semiconductor nanocrystals obtained using plasmon-enhanced optical spectroscopy, including surface enhanced Raman scattering (SERS) and plasmon-enhanced IR absorption, is presented. These methods are based on the amplification of the phonon response of semiconductor nanocrystals located in the field of localized surface plasmon resonance (LSPR) of metal nanostructures. Owing to the choice of a specific morphology of metal nanostructures, coincidence of the LSPR energy with the laser excitation energy and / or the energy of optical phonons in nanocrystals is provided. Resonant conditions ensure a significant increase in local electric fields and, as a result, a sharp increase in the Raman signal and IR absorption at the frequencies of surface optical phonons of nanocrystals. Amplification of the optical response makes it possible not only to detect monolayer coatings of nanocrystals, but also to study their crystal structure, phase and element compositions, and internal mechanical stresses. Application of Raman scattering (RS) in combination with atomic force microscopy with the use of a metallized probe has opened up new possibilities for analyzing the vibrational and electronic spectra of nanocrystals with nanometer spatial resolution [ABSTRACT FROM AUTHOR]

Background. According to the synthesis and properties of mixed metal complexes of 3d metals with V (V) and 5-phenyl-1,3,4-oxadiazole-2 (3H) -thione, it has not been reported in the literature. The synthesis of mixed-metal complex compounds opens up new aspects of coordination chemistry. Purpose. A procedure will be developed for the synthesis of new mixed-metal complexes of Co (II), Ni (II), Cu (II) and Mn (II) chlorides with 5-phenyl-1,3,4-oxadiazole-2 (3H) -thione based on ammonium vanadate. The study of the composition and structure of mixed metal complex compounds with modern physicochemical methods. Methodology. A technique for the synthesis of mixed-metal complex compounds has been developed. For synthesis, an aqueous solution of ammonium vanadate and metal chlorides was added to the alcohol solution of the ligand (M: M: L: 1: 1: 1: 2 mol), pH = 8. The reaction mixture was heated for 40 minutes. Originality. А procedure was developed fot the synthesis of new mixed-metal complexes of Cо(II), Ni(II), Cu(II) and Mn(II) chlorides with 5-phenyl-1,3,4-oxadiazole-2(3H)-thione based on ammonium vanadate. Coordinated competing donor centers, electronic and geometric structures of the ligand molecule were studied on the basis of the quantum-chemical software package Gaussian09 LanL2DZ. It was shown that the formation of the complex of ligand-5-phenyl-1,3,4-oxadiazole-2 (3N) -thione is partially coordinated through a localized nitrogen or sulfur atom. Findings. Coordinated competing donor centers, electronic and geometric structures of the ligand molecule were studied on the basis of the quantum-chemical software package Gaussian09 LanL2DZ. The composition and structure of the synthesized mixed-metal complex compounds were studied using elemental analysis, derivatographic analysis, and IR spectroscopy. [ABSTRACT FROM AUTHOR]

Introduction. Studies have been conducted to develop a method for determining the pectin esterification degree in order to limit the use a significant number of costly and hardly available reagents. Materials and methods. The samples of apple and citric pectin were exhibited at Kyiv market with the different degree of esterification according to accompanying documentation. IR-spectroscopy research was provided on device Nexus-475 Nicolet firm. NMR-spectrums were registered by NMR-spectrometer Mercury, VARIAN firm. Mathematical treatment of the results is done according to mathematical modeling concept. Results and discussion. In the IR spectrum of low-esterified pectin, this band is low intensity and is in the oscillations region of 1686.71 cm-1. In spectrum of high-ester pectin the intensive line with three maximums at 3400.56 cm-1, 3316.52 cm-1, 3271.70 cm-1, which corresponds to stretching vOH. In IR-spectrums with esterification till 42% the line of free carboxyl group is available, in IR-spectrums of high-esterified pectin there is an intensive line of carboxylate groups (CO2-), and that differs the given spectrums. The given characteristics of NMR-spectrums show the difference in structure of high- and low-esterified pectin, but it does not give an opportunity to conduct the quantitative determination of esterification degree. While analyzing the results we can make a conclusion that the degree or hyperbolic models are the best for prognosing. The difference between chemical method of esterification degree determination and suggested method is 0.6-1.3%. Conclusions. Determination of the pectin degree esterification is possible by tyranic acidity with subsequent calculation by the regression equation. [ABSTRACT FROM AUTHOR]

• A procedure for the synthesis of the anhydrous CeF 4 by the reaction between CeF 3 and XeF 2 was proposed. • Characterization of the forming CeF 4 was carried out by XRD, FTIR, 19F NMR and thermogravimetry. • The anhydrous CeF 4 was found to undergo hydration when exposed to air. • An approximate formula [CeF 4 •0.2H 2 O]*0.7H 2 O for the crystalline hydrate, formed after exposure to air, was proposed. By reacting CeF 3 with XeF 2 the anhydrous CeF 4 was synthesized and studied by XRD, SEM, FTIR, 19F NMR spectrometry and thermogravimetry. It was found that CeF 4 undergoes hydration upon keeping in air forming the crystalline hydrate with the approximate formula [CeF 4 •0.2H 2 O]*0.7H 2 O. Water molecules both enter the coordination sphere of cerium and form crystalline hydrates with cerium(IV) fluoride due to OH...F hydrogen bonds in the crystal lattice. [Display omitted] [ABSTRACT FROM AUTHOR]

A new approach for synthesis of copper(II) complexes with 1-methyltetrazole based on oxidative dissolution of metallic powdercopper in ethanol – HCl (ammonium thiocyanate) was developed. Composition and structure of the complexes prepared were studied by elemental analysis, X-ray diffraction and infrared spectroscopy in the middle (4000–400 cm–1) and long wave (400–50 cm–1) field. In all complexes ligand shows monodentate coordination. Polymeric structure of complexes studied is formed due to bridging coordination of anions. Magnetochemical studies revealed that copper(II) chloride complexes a low-temperature ferromagnetic.