The results of studies to determine the effect of titanium dioxide nanoparticles (nanoTiO 2 ), finely dispersed anatase crystalline titanium dioxide (anatazTiO 2 ) and surface-active substances (surfactants) on the compressive strength, degree of permeability and thermal stability of concrete samples are presented. Adding particles of nanotitanium, anatase titanium and surfactants up to 2 % to cement accelerates the hydration process and increases the strength of concrete, and also has a strong effect on its microstructure.As a result of the studies, it is experimentally proved that the compressive strength of concrete increases with the addition of titanium dioxide (nanoTiO 2 ) nanoparticles by 23.2 %, finely dispersed anatase crystalline titanium dioxide (anatazTiO 2 ) by 21.7 % to 5 % concentration by weight. Original Research Article: full paper (2020), «EUREKA: Physics and Engineering» Number 2 20Chemical EngineeringIn addition, the introduction of these additives reduces the permeability of concrete. This is due to a decrease in the absorption of concrete by water with the addition of nanotitanium and anatase titanium. The introduction of additives from 1 % to 5 % by weight in concrete reduces the depth of chloride penetration by 10-15 times, compared with the control.The use of temperature-programmed desorption mass spectrometry (TPD-MS) method has shown that an increase in the percentage of TiO 2 nanoparticles to 5 % in concrete mixtures correlates with an increase in microporosity and dispersion level of these mixtures, which causes a shift in the peaks of intense gas evolution from the samples when heated to the side low temperatures (for example, carbon dioxide CO 2 ).The resulting concrete samples are planned to be used for the manufacture of floors in livestock buildings. The injected additives are selected because they are not toxic substances and, in contact with the biological environment of livestock buildings (urine, feces), will not react with them.
Long-term operation of reinforced concrete structures in the conditions of chemical enterprises has a powerful negative impact on the physical and chemical properties of concrete, which leads to its destruction. The aim of this research is to determine the effect of biological and chemical corrosion on concrete structures in the workshop for the production of titanium dioxide by the sulphate method and the storage of finished products. In particular, chemical production for the synthesis of titanium dioxide by the sulfate method causes the rapid course of chemical (acid and sulfate) and microbiological (thionic bacteria and microscopic fungi) corrosion processes. These corrosion processes reinforce each other according to a synergistic principle. As a result, temperature-programmed desorption mass spectrometry (TPD MS) and scanning electron microscopy have experimentally proven the presence and spatial localization of colonies of thionic bacteria and microscopic fungi in concrete structures. Correlations between the intensity of biochemical corrosion and the depth of damage to the microstructures of concrete structures have been established. Moreover, a change in the chemical composition of concrete in the workshop for the production of titanium dioxide (increased SO2 content and reduced CO2) and the formation of gypsum crystals (CaSO4 2H2O) as a result of the dissimilation of microorganisms was established. Also, in the storage room for finished products, calcium citrate crystals and a violation of the formation of calcium carbonate are formed in the surface layers of concrete. In addition, the results of the study can be used to develop antimicrobial and anticorrosive protective agents to stop the biochemical corrosion of concrete in a chemical plant
t. A large number of dairy cows in Ukrainian farms suffer from subclinical mastitis, which leads to significant economic losses in agriculture. Conditioned upon the lack of clinical manifestations it is difficult to detect, in particular, explained by insufficient information about the microbial composition of milk. The ban on the use of antibiotics for productive animals is forcing new safe and effective remedies. The aim of the study was to determine the therapeutic effect of Bacillus megaterium NCH 55 in subclinical mastitis of Holstein cows. Research materials – milk of cows with subclinical mastitis, isolates of microorganisms and B. megaterium NCH 55. Methods used: California test for mastitis; microscopic test to count the total number of somatic cells by the method of Prescott and Britt; bacterial method for the study of microorganisms; polymerase chain reaction to determine Mycoplasma spp. in milk; spectrophotometry; method VI Brillis to determine the adhesive properties of Bacillus megaterium NCH 55; determination of antagonistic properties of B. megaterium by diffusion into agar wells; the method of flow cytometry using the device “SomaCount Flow Cytometer”; physiological. The experiment was conducted in dairy farms of the North-Eastern region of Ukraine: LLC agrofirm “Lan”, LLC agrofirm “Vorozhbalatinvest”, LLC agrofirm “Vladana” in the period February-August 2021. Isolates of S. aureus, S. agalactiae, E. coli enterohemorrhagic, E. coli, Candida, E. fecalis, S. epidermidis and Mycoplasma spp. were detected in milk samples from cows with subclinical mastitis. Microscopic studies have shown that Bacillus megaterium NCH 55 are white gram-positive rods that have low adhesive properties and form spores. The greatest antagonism of B. megaterium is shown in relation to bacterial isolates in concentration of 1×109 , CFU/g. In 70% of cows that reached a productivity of more than 30 kg/day on the 30th day of research, milk parameters such as the number of somatic cells (CSC ≤400 thousand/cm3 ) and the number of mesophilic aerobic and facultative anaerobic microorganisms (kMAFANM) (≤100 thousand CFU/cm3 ) corresponded to the class “Extra”. The recovery time of animals with subclinical mastitis depended on the degree of damage to the breast and individual characteristics of the organism. Cows that did not reach a productivity of 30 kg/day continued treatment individually. The number of somatic cells in the milk of cows was ≤500 thousand/cm3 and kMAFAnM ≤200 thousand CF/cm3
The object of this study is the regularity of changes in the biogenic destructive effect of microorganisms on the concrete structural elements of livestock facilities due to the use of the original liquid phase mixture of disinfectant based on aldehyde and surfactant. Microorganisms use construction materials as a substrate for growth and nutrition; they produce citric acid, which leads to a change in the composition and morphology of hydrated cement new formations. The composition of the microflora of the pigsty has been determined, and the minimum concentration of disinfectant based on glutaraldehyde and didecyl dimethyl ammonium chloride was found. By the TPD MS method, a decrease in the intensity of carbon dioxide (CO2) release in concrete samples during the heating of the sample to 900 °C was proved, compared to the control intact corrosion sample. Electron microscopy of concrete samples shows the presence of destructive changes and colonies of micromycetes. It was established that calcite was intensively released in the control sample of concrete, which retained its integrity and was not subjected to corrosion when heated to a temperature of 600 °C. Electron microscopy confirms the preservation of the homogeneous structure of concrete. The use of a disinfectant based on glutaraldehyde and didecyl dimethyl ammonium chloride at a concentration of 1 % destroys colonies of micromycetes, 2 % – the shell of microorganisms, and 3 % – biofilm. Treatment of concrete with a disinfectant at a concentration of 3 % destroys microorganisms Aspergillus fumigatus and Penicillium oxalicum, inhibits the process of biological corrosion of concrete, and strengthens the structure of concrete. The results of the experiment can be applied to inhibit the corrosion of concrete and extend the life of building structures made of concrete through the use of a disinfectant based on aldehyde and didecyl dimethyl ammonium chloride at a concentration of 3 %.
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