MULTICOMPONENT FeCoCrAlTiCuMo COATING CREATED BY ATMOSPHERIC PLASMA METALLIZATION WITH MULTIPLE REFLOW

The microstructure and phase composition of the coating obtained by plasma spraying of FeCoCrAlTiCuMo powder in an equiatomic ratio of components have been investigated. The results showed the possibility of creating a multicomponent single-phase solid solution by plasma spraying and the expediency of studying it.

ДОЦІЛЬНІСТЬ ЗАСТОСУВАННЯ СТЕРИЧНО УСКЛАДНЕНИХ АЦЕНАФТЕНОВИХ СПОЛУК У СКЛАДІ ПРОТИКОРОЗІЙНОЇ КОМПОЗИЦІЇ

Goal. Synthesis and study of the effect of the inhibitory component – sterically complicated acenaphthene compounds – on the effectiveness of the protective composition to prevent corrosion of metal products during the period of temporary preservation.Method. Coke-chemical acenaphthylene was isolated from the absorbing and anthracene fractions of coal tar, the bromination of which led to 1,2-dibromocenaphthene. Subsequent alkylation of azine bases with 1,2-dibromacenaphthene yielded a number of sterically complex acenaphthene compounds. In the conditions of simulation aggressiveness of NSS environment the influence of synthesized additives on efficiency of anticorrosive composition is investigated (ISO 9227:2017). Research methods: chromatography, synthesis, elemental analysis, IR spectroscopy, corrosion tests.Results. On the basis of low-demand, available and inexpensive components of coke production, a number of substances with high anti-corrosion properties were synthesized – Quaternary azine salts with acenaphthene fragment. It was determined that the greatest resistance to the destructive effects of corrosive NSS environment according to the results of accelerated atmospheric corrosion tests was demonstrated by a composite coating containing an inhibitory additive – 1-(2-bromo-1,2-dihydroacenaphthylen-1-yl) quinoline bromide. The dominant role of the structure of the inhibitory additive on the manifestation of anticorrosive properties of the protective composition is shown. The influence of the ratio of components of paints and varnishes on their technological and anti-corrosion properties has been studied. The obtained results allow to create a new formulation of the domestic competitive protective composition to prevent corrosion of the metal for the period of temporary preservation.Scientific novelty. The role of 1,2-dibromacenaphthene as a promising alkylating agent in the synthesis of inhibitory additives - sterically complicated acenaphthene compounds has been determined.Practical significance. The optimal content of inhibitory components – Quaternary azine salts with acenaphthene fragment – for the development of a formulation of an effective anti-corrosion composition for the period of temporary preservation of metal products.

Attraction of the Mosquitoes Aedes aegypti and Aedes albopictus (Diptera: Culicidae) to a 3-Part Phytochemical Blend in a Mesocosm

Aedes aegypti (L.) and Aedes albopictus (Skuse) mosquitoes of both sexes were attracted to a 3-part volatile synthetic phytochemical blend but differed according to their component ratios, 7:3:2 or 1:1:1, and their initial concentrations. These arbovirus vectors were presented with the blends as baits in paired baited and blank CFG traps in a large greenhouse mesocosm. Ae. aegypti attraction was highest at a 7:3:2 blend ratio, but at a concentration half that found most effective for an anopheline mosquito species in outdoor screenhouses. Both lower and higher concentrations yielded substantially lower attraction scores for Ae. aegypti. By contrast, the few tests conducted on Ae. albopictus showed that it was not as sensitive to concentration, but again it was more responsive to the 7:3:2 ratio of components than to the 1:1:1 ratio. The two sexes of both species were represented equally in the trap catches, indicating the potential value of this and similar attractive blends for population surveillance and control of Aedes mosquitoes.

Comparative analysis of the effectiveness of inhibitor-protected cephalosporins fortified with basic antibiotic

Inhibitor-protected cephalosporins are an important tool against hospital infections caused by extended spectrum β-lactamase producers. At the same time, the relative deficiency of the basic antibiotic in combination with the β-lactamase inhibitor sulbactam (1: 1) may be associated with the risk of therapeutic failure.Objective. To compare therapeutic effect of various regimens for prescribing inhibitor-protected cephalosporins in children with severe bacterial infection.Children characteristics and research methods. The authors compared clinical efficacy of cefotaxime / sulbactam, cefoperazone / sulbactam, cefepime / sulbactam at maximum doses and main component-fortified-cefepime / sulbactam. The study included 92 patients aged from 2 months to 12 years with appendicular peritonitis, acute purulent osteomyelitis, complicated hospital infections of the lower respiratory tract, exacerbation of chronic purulent otitis media and chronic urinary tract infections. It was found that inhibitor-protected cephalosporins with a 1: 1 ratio of components more often necessitated a change in therapy. The use of drugs initially containing a basic antibiotic in a high dose (component ratio 2:1) or additionally fortified with a basic antibiotic demonstrated a higher therapeutic efficacy.

Physicochemical properties of graft copolymers of collagen and fibroin with polyacrylic acid

Certain physicochemical properties of the synthesized graft copolymers of raw skin collagen and natural silk fibroin with polyacrylic acid have been determined. The dependence of the solubility, density, and thermal properties of copolymers on the ratio of components and synthesis conditions has been established.

MODIFIED WITH VARIOUS ADDITIVES ARYLALYCLIC COPOLYIMIDES AND COMPOSITE FILMS BASED ON THEIR BASIS

lopment of arylalicyclic copolyimides based on alicyclic dianhydride, aromatic dianhydrides of benzophenone- and diphenyloxidetetracarboxylic acids with 4,4'-diaminodiphenyl oxide at various ratios of alicyclic and aromatic dianhydrides, as well as various compositions based on these copolymers with low- or other high-molecular compounds that enhance the characteristics of the polymer matrix. Composite films were formed from solutions of the obtained polymer mixtures, and their properties were studied. It was noted that at optimal ratio of components, the films have improved thermal and strength properties, etc., exceeding the analogous properties of the initial arylalicyclic copolymer, while the elasticity has acceptable values for such material. The best characteristics had the composite films formed from a ternary composition of copo-lyimide-polyethylene glycol-alkylated montmorillonite. Metal-containing composite films, along with higher thermal stability compared to unmodified copolyimide, were resistant to aggressive reagents, lower values of specific volume and surface resistance, higher viscosity values, and different colors depending on the nature of the salt. By introducing a silicon-containing compound into the copolyimide solution, the new polymer systems have been obtained, and the porous films could be formed.

Kinetics Investigation of the Formation of a Gas-Resistant Glass-Forming Layer during the Oxidation of ZrB2-MoSi2-Y2O3-Al Coatings in the Air Atmosphere

In this article, the coatings of ZrB2-xMoSi2-Y2O3-yAl (x = 24, 35, 45 wt %; y = 10, 15, 20 wt %) were applied to the surface of a carbon/carbon composite to protect against high-temperature oxidation using a multi-chamber detonation accelerator. The kinetic analysis of the formation processes of a glass-forming layer during the oxidation of the initial components of the system ZrB2-MoSi2-Y2O3-Al in an air atmosphere at a temperature of 1400 °C was carried out and the kinetically significant stages of the heterogeneous reaction were determined. It is shown that the speed and density of the formation of a glassy matrix can be adjusted by fine-tuning the ratio of components in the initial powder.

One-Stage Catalytic Oxidation of Adamantane to Tri-, Tetra-, and Penta-Ols

Tertiary tetraols of adamantane (C10H16, Tricyclo[3.3.1.1(3,7)]decan) have been widely used for the synthesis of highly symmetric compounds with unique physical and chemical properties. The methods for one-stage simultaneously selective, deep, and cheap oxidation of adamantane to tetraols of different structures have not yet been developed. In this research, chemically simple, cheap, and environmentally friendly reagents are used and that is the first step in this direction. The conditions, under which the impact of a hydrogen peroxide water solution on adamantane dissolved in acetonitrile results in full conversion of adamantane and formation of a total 72% mixture of its tri-, tetra-, and penta-oxygenated products, predominantly poliols, have been found. Conversion and adamantane oxidation depth are shown to depend on the ratio of components of the water-acetonitrile solution and the method of oxidizer solution introduction when using the dimer form of 1:1 dimethylglyoxime and copper dichloride complex as a catalyst. Under the conditions of mass-spectrometry ionization by electrons (70 eV), fragmentation across three C–C bonds of the molecular ions framework of adamantane tertiary alcohols Ad(OH)n in the range n = 0–4 increases linearly with the rise of n.

Effect of Mechanical Activation and Gamma-Irradiation on Structural-Phase State of Ti-Al-C Powder Reagents

The influence of mechanical activation and gamma-irradiation on the structural-phase state of Ti-Al-C powder reagents was studied. The following compositions were used for research: 1) 78% Ti + 14% Al + 8% C; 2) 80% Ti + 12% Al + 8% C; 3) 81% Ti + 10% Al + 9% C. Mechanical activation of these compositions leads to an increase in the diffuse background, a decrease in the intensity of diffraction reflections of mixture components and a broadening of peaks, as well as micro-deformations. Depending on the ratio of components, the structural parameters can either increase in comparison with the initial ones, or decrease. The effect of gamma radiation with a dose rate of 1 Gy/s and accumulated dose of 3·104 Gy on the mechanocomposites of the Ti-Al-C system causes unsystematic change in crystal lattices of elements, which can be explained by radiation-stimulated diffusion. Gamma-irradiation also reduces micro-deformations that occur after mechanical activation, while crystallites of the components remain nanoscale.