Anti-corrosion ceramic coatings on the surface of Nd-Fe-B repelling magnets

The results of vacuum-arc deposition of thin ZrO₂coatings to protect the surface of Nd-Fe-B permanent magnets used as repelling devices in orthodontics are presented. The structure, phase composition and mechanical properties of zirconium dioxide films have been investigated by means of SEM, XRD, EDX, XRF and nanoindentation method. It was revealed the formation of polycrystalline ZrO₂ films of monoclinic modification with average grain size 25 nm. The influence of the ZrO₂ coating in terms of its barrier properties for corrosion in quasi-physiological 0.9 NaCl solution has been studied. Electrochemical measurements indicated good barrier properties of the coating on specimens in the physiological solution environment

ГРАНУЛООБРАЗОВАНИЕ В ПОРОШКООБРАЗНЫХ МАТЕРИАЛАХ ПРИ ИСПОЛЬЗОВАНИИ ТЕХНОЛОГИИ «FATTENING»

In this paper we considered the granules formation process using the "fattening" technology in a granulation bowl. Development of rolling overgranulation technology primarily due to the need to obtain granules of larger size with much better quality indicators than those that can be attained in granular towers. Also, this technology gives granules with a complex chemical composition. Fattening is the process of overgranulation of an initial pellet by powder (with or without binding) by rolling in different devices, including bowls. The mathematical description of various embodiments of the process: with or without the birth of pellets. Besides, the process of fragmentation of the granules is considered separately. Fragmentation is usually an undesirable process, but sometimes it is not possible to get rid of it. The calculation results obtained by the models are represented as a series of graphic dependencies. We also develop algorithms that allow for the effect of fragmentation and agglomeration in arbitrary ratios. A block diagram of the implementation of the algorithm is also presented in the paper.Р ассмотрен процесс гранулообразования при использовании технологии «fattening» в грануляторах тарельчатого типа. Дано математическое описание различных вариантов протекания процесса, в том числе с учетом зарождения гранул и их возможного дробления

Влияние образования отложений в порах фильтровальной перегородки на процесс фильтрации

The aim of the work is to consider the mechanism of clogging the pores of the filter unit by small particles from the flow of filtrate inside them. Theoretical ideas about the process of filtering with the deposition of small particles from the filtrate on the pore walls and attribution of its fundamentals to restructuring from the original structure to the final structure allow to describe the process of clogging the pores using well studied concepts of known processes with phase transformations (in particular, crystallization). Based on this analogy and the approach to the description of the transformation of the "old" structure into a "new" one in time, using experimental data and their processing we calculated the rate of nucleation of the sediment centers (ωnucl), the linear (υlin) and volumetric rates of sediment plaques growth in the pores of the filter unit at different values of the process driving force, at different pressure difference in the system, and at different concentrations of solid particles in the suspension. Interpolation and extrapolation dependences were obtained for analyzing the mechanisms of sediments formation and growth for determining and calculating these (ωnucl, υlin) rates. Using the concepts of nonequilibrium thermodynamics to assess the influence of the driving forces we studied their influence (changes in the concentration of solid particles in the filtrate suspension and pressure drop across the filtering layer) on the dynamics of the filtration process. Using the data obtained it is possible to find the degree of clogging of through pores, which determines the filtration conditions, the filter septum type, and the filter overall dimensions.Целью работы является рассмотрение механизма закупоривания пор фильтрующего блока мелкими частицами из протекающего внутри них потока фильтрата. Теоретические представления о ходе процесса фильтрования с отложением на стенках пор частиц мелких фракций из фильтрата и отнесение его основ к протеканию процессов с перестройкой из исходной структуры в конечную позволяют описать процесс закупорки пор, используя хорошо изученные представления известных процессов с фазовыми превращениями (в частности, кристаллизацию). Опираясь на эту аналогию и подход к описанию процесса превращения «старой» структуры в «новую» во времени, рассчитали скорости зарождения центров отложений (ωnucl), линейную и объемную скорости (υlin) роста отложений в порах фильтровального блока фильтра при различных значениях движущей силы процесса, разности давлений в системе, при разных концентрациях твердых частиц в суспензии. Получили интерполяционные и экстраполяционные зависимости для анализа механизмов образования и роста отложений определения и расчета этих (ωnucl, υlin) скоростей. С использованием представлений неравновесной термодинамики для оценки влияния движущих сил изучено их влияние (изменения концентрации твердых частиц в суспензии фильтрата и перепада давления на фильтрующем слое) на динамику процесса фильтрования. Используя полученные данные, можно найти степень закупоривания сквозных пор, которая определяет условия проведения фильтрации, тип фильтровальной перегородки, габаритные размеры фильтра

Comparative Assessment of Prospective Protein Bases for Microbiological Media

Objective of the work is to carry out comparative assessment of the pancreatic hydrolysates of protein-containing products, both phytogenous and zoogenous, as nutrient base for microbiological media. Gelatine, soy, soy concentrate, maize gluten, fish meal, common kilka, and bovine blood have been used as a feedstock. Protein stuff hydrolysis, hydrolysate purification, and validation of physical-chemical properties were performed in accordance with conventional techniques. Testing of peptone biological parameters has been carried out on the model of nutrient agar using Shigella flexneri 1a 8516, Shigella sonnei “S form”, Pseudomonas aeruginosa 27/99, Serratia plymuthica 1 test strains. Identified have been physical-chemical parameters of the hydrolysates under study. Detected are the variations in quantity, diameter and frequency of dissociation among the colonies of Shigella flexneri 1a 8516, Shigella sonnei “S form”, chromogenesis in Pseudomonas aeruginosa 27/99, Serratia plymuthica 1, cultivated on agar media with hydrolysates under study. Obtained are the comparative data on physical-chemical and biological parameters of all experimental hydrolysates, which offers an opportunity to differentiate their choice when adding them into bacteriological nutrient media

Green synthesis of silver nanoparticles using aqueous extract of hot chili pepper fruits and its antimicrobial activity against Pseudomonas aeruginosa

Green synthesis of different nanoparticles using the plants aqueous extracts has several advantages over other methods due to the environmentally favorable nature of plants. Moreover, such approach is also cost effective. This work describes the biosynthesis of silver nanoparticles (Ag-NPs) with the use of the aqueous extract of dry pericarps of hot chili peppers (Capsicum sp. cv. Teja (S-17) and cv. Carolina Reaper) with different levels of pungency and their antibacterial effect on the antibiotic resistant Pseudomonas aeruginosa. Phytochemical screening of pericarp tissues showed great distinction in contents of phenolic compounds and capsaicinoids as potential reducing agents wich correlated with total antiradical activity as analyzed by reduction of DPPH radicals. The biosynthesized Ag-NPs were characterized by UV-vis spectrophotometry and scanning electron microscopy (SEM). The average size of the nanoparticles in both samples was less than 25 nm. Іnitial concentration of both samples of Ag-NPs inhibited P. aeruginosa growth with equal efficiency

Experimental Solid Medium for Legionella Cultivation

Presented is the principal scheme for preparation of experimental medium for Legionella cultivation on the basis of fermentative hydrolysate of pig lung. Shown is that the culture medium has good growth properties and meets the requirements of regulatory documentation for culture medium used for isolation and cultivation of the causative agent of legionellosis