Hemagglutination in gill capillaries of sheepshead, Archosargus probatocephalus (Perciformes: Sparidae), infected by a myxosporidean

During a survey Myxozoa, four specimens of the sheepshead (18 ± 1.5 cm and 59 ± 2.5 g) (Archosargus probatocephalus) were collected in the Ipioquinha river (Maceió/AL). Transmission electron microscopy observations revealed erythrocyte agglutinations in gill capillaries located near spherical cysts containing myxospores of the genus Henneguya. This hemagglutination partially or totally obstructed the gill capillaries. Erythrocytes occurred in close adherence to each other, with a closed intercellular space. A few lysed erythrocytes were observed among agglutinated cells. The reduced lumen of the capillaries was partially filled with amorphous dense homogenous material adhering to the erythrocytes. In addition, heterogeneous masses of irregular lower electron density were observed in the reduced channel of the capillary. The agglutinated erythrocytes appeared dense and homogenous, lacking cytoplasmic organelles. The nuclei had the appearance of normal condensed chromatin masses, generally without visible nucleoli. This occurrence of hemagglutination only in the capillaries located in close proximity to the developing myxozoan cysts suggests that parasite development may be a factor triggering erythrocyte agglutination. This is supported by previous experimental studies that showed a probable correlation between parasitic infections and hemagglutination. Nonetheless, further studies are necessary in order to better understand the physicochemical processes involved in this phenomenon.

Gas brazing of thin-sheet galvanized steel with aluminum solders

. In this work, the first stage of experimental research was carried out to estimate the main physicochemical processes that determine the qualitative characteristics of a brazed joint made of thin sheet galvanized steel during gas brazing with aluminum solder systems. In particular, an estimation was made of the ability of spreading and wetting of aluminum solders (AlSi5, AlSi12) on the surface of thin sheet galvanized steel ( DX56D + Z of 0.4 mm thick and zinc-coated layer of 45–65 microns) at a step-by-step increase in the heating area of the base metal in the presence and absence of flux (Al-Flux 726). The aluminum alloys was heated “not directly,” but through the base metal to maximize the preservation of the anticorrosive zinc coating at the interface between the liquid solder and the base material.

Relationship between corrosion and nanoscale friction on a metallic glass

Metallic glasses are promising materials for micro-devices, where corrosion and friction limit their effectiveness and durability. We investigated nanoscale friction on a metallic glass in corrosive solutions after different immersion times using atomic force microscopy to elucidate the influence of corrosion on nanoscale friction. The evolution of friction upon repeated scanning cycles on the corroded surfaces reveals a bilayer surface oxide film, where the outer layer is removed by the scanning tip. Friction and adhesion after different immersion times in different solutions allow to compare the physicochemical processes of surface dissolution at the interfaces of the two layers. The findings contribute to the understanding of mechanical contacts with metallic glasses in corrosive conditions by exploring the interrelation of microscopic corrosion mechanisms and nanoscale friction.

Numerical modeling of strong effects on ionospheric plasma

В работе представлены постановка задачи начальной стадии мощного антропогенного возмущения ионосферы для последующего вычисления высотно-временного распределения ионосферно-магнитосферных параметров. Данная задача имеет огромное значение в плане теоретического исследования таких возмущений на математических моделях изучаемой среды. Такие возмущения сопровождаются различными физико-химическими процессами, которые к настоящему времени плохо изучены. Основным источником сильных возмущений ионосферы являются мощные электромагнитные излучения (сильная солнечная вспышка, мощный ядерный взрыв). Такие электромагнитные возмущения могут вызывать сильнейшие глобальные перераспределение всей атмосферы Земли, которые к настоящему времени недостаточно надежно изучены, и одним из способов их изучения, является математическое моделирование. Приводится результаты вычислительного эксперимента начальной стадии ионизации нейтрального газа, которые могут помочь в дальнейшем исследовании такого процесса. The paper presents the formulation of the problem of the initial stage of a powerful anthropogenic disturbance of the ionosphere for the subsequent calculation of the altitude-time distribution of the ionosphere-magnetospheric parameters. This problem is of great importance in terms of the theoretical study of such perturbations on mathematical models of the studied environment. Such disturbances are accompanied by various physicochemical processes, which are poorly understood by now. The main source of strong disturbances in the ionosphere are powerful electromagnetic radiation (strong solar flare, powerful nuclear explosion). Such electromagnetic disturbances can cause the strongest global redistribution of the entire atmosphere of the Earth, which by now have not been sufficiently studied reliably, and one of the ways to study them is mathematical modeling. The results of a computational experiment of the initial stage of ionization of a neutral gas are presented, which can help in further investigation of such a process.

Production of corundum armored ceramics

The purpose of this study was to develop the compositions and technology of corundum armored ceramics with high ballistic characteristics based on aluminum oxide with an α-Al2O3 content of more than 99 wt.%. The results of the study of the physicochemical processes of obtaining corundum ceramics modified with complex additives consisting of magnesium - aluminosilicate eutectic mixture and oxides of magnesium, yttrium, titanium, zirconium are presented. The introduction of complex additives into the composition of corundum ceramics provides a significant reduction (100-150°C) of the sintering temperature of the product. In this case, additives of yttrium and zirconium oxides contribute to the formation of a uniform-grained microstructure of ceramics, and in the case of adding titanium oxide, a collective recrystallization of corundum grains is noted. The use of small additives (0.3-0.5 wt.%) of magnesium and yttrium oxides together with a eutectic mixture in the compositions of corundum ceramics based on high-quality alumina contributes to the formation of a uniform-grained, dense structure of the material and giving it a high level of physical and mechanical properties as a result of directional the action of each component of the additive on the physicochemical processes of phase formation of the crystalline matrix. A model idea of the mechanism of action of additives on the formation of the microstructure of ceramics during stage-by-stage heating from 1350 to 1650°C in the sintering mode of products is presented. The developed compositions and technologies of corundum armored ceramics have a production focus and implementation in practice.

Successive H-atom Addition to Solid OCS on Compact Amorphous Solid Water

Carbonyl sulfide (OCS) is an abundant sulfur (S)-bearing species in the interstellar medium. It is present not only in the gas phase, but also on interstellar grains as a solid; therefore, OCS very likely undergoes physicochemical processes on icy surfaces at very low temperatures. The present study experimentally and computationally investigates the reaction of solid OCS with hydrogen (H) atoms on amorphous solid water at low temperatures. The results show that the addition of H to OCS proceeds via quantum tunneling, and further addition of H leads to the formation of carbon monoxide (CO), hydrogen sulfide (H2S), formaldehyde (H2CO), methanol (CH3OH), and thionformic acid (HC(O)SH). These experimental results are explained by our quantum chemical calculations, which demonstrate that the initial addition of H to the S atom of OCS is the most predominant, leading to the formation of OCS-H radicals. Once the formed OCS-H radical is stabilized on ice, further addition of H to the S atom yields CO and H2S, while that to the C atom yields HC(O)SH. We have also confirmed, in a separate experiment, the HC(O)SH formation by the HCO reactions with the SH radicals. The present results would have an important implication for the recent detection of HC(O)SH toward G+0.693–0.027.

Density and Viscosity of LiCl, LiBr, LiI and Kcl in Aqueous Methanol at 313.15K

The densities and viscosities of electrolytes are essential to understand many physicochemical processes that are taking place in the solution. In the present research, the densities and viscosities of lithium halides, LiX (X = Cl, Br, I ) and KCl in (0, 20, 40, 50, 60, 80 and 100) mass % of methanol + water at 313.15K were calculated employing experimental densities (ρ), the apparent molar volumes( ϕv) and limiting apparent molar volumes (0v) of the electrolytes. The (0v) of electrolyte offer insights into solute-solution interactions. In terms of the Jones-Dole equation for strong electrolyte solution, the experimental data of viscosity were explored. Viscosity coefficients A and B have been interpreted and discussed. The B-coefficient values in these systems increase with increase of methanol in the solvents mixtures. This implied that when the dielectric constant of the solvent decreases, so do the solvent-solvent interactions in these systems.

Video registration of physicochemical processes in BOF cavity at bath top blowing at application oxygen lances of various designs. Report 1. Facility and methodology of the study

Interaction of the upper oxygen jets with the BOF bath considerably effects the hot metal refining flow. To optimize the lances designs and methods of BOF bath blowing, information is needed on the actual physical and technical phenomena taking place during top blowing of BOF bath by groups of ultrasonic and sonic oxygen jets. It was shown that obtaining the information is possible at high temperature simulation of the BOF bath blowing by application oxygen lances of various designs and video registration. Results of previous studies by filming of the blowing in a BOF and OHF presented. Description of modern facilities of high temperature simulation within a multi-purpose 160 and 60‒80 kg BOFs, equipped by special manholes for observation and registration by video camera the physicochemical processes taking place on the surface of the bath presented. In particular the manholes made it possible to observe the processes taking place at various methods of top and combined blowing of the BOF bath by application regular, two-circuit and double-flow oxygen lances. A methodology of test heats carrying out presented, which ensured obtaining important practical information on forming and variation of dimensions of the reaction zone. In particular, information was obtained about the interaction of ultrasonic and sonic oxygen jets with the metal melt, development of afterburning, emission out of reaction zone C to CO2 in the subsonic and sonic oxygen jets with forming high temperature flares directed on the BOF bath surface or penetrated in the foamed slag, emissions of slag-metal suspension out the BOF, forming of metal-slag sculls on the lance tube during the blowing with various level of foamed slag-metal emulsion.

Chitosan and graphene oxide-based nanocomposites for water purification and medical applications: A review

Chitosan (CS) is a natural polysaccharide isolated from insects, molluscs, and fungi. The specific properties of chitosan can be enhanced using physicochemical processes. The composites prepared using CS and graphene oxide (GO) contain active functional groups such as epoxide, carboxyl, and hydroxyl, which possess excellent biocompatibility, high adsorption capacity, and biodegradability. Their low cost and ease of scale-up make them employable for multiple applications in water-treatment plants, electronics, solar cells, and pharmaceuticals. This review provides an overview of sources, types, and properties of chitin, chitosan, and graphene oxide. The use of these composites for the preparation of anti-microbial drugs has been discussed here. The article also explores the applicability of such composites for removal of heavy metals (lead, copper, chromium, cobalt, mercury, etc.), dyes (methylene blue and other reactive dyes), and organic and inorganic contaminants (ofloxacin, naphthanol, phenol, and oil, etc.). The article highlights various knowledge gaps in the field and the scope of future work.