3 research outputs found
Study of thermal effects of silicate-containing hydroxyapatites
The possibility of modifications of hydroxyapatite silicate ions, from the extracellular fluid prototype solution under near-physiological conditions has been studied. Formation of silicon-structured hydroxyapatite with different extent of substitution of phosphate groups in the silicate group has been established through chemical and X-ray diffraction analyses, FTIR spectroscopy and optical microscopy. The results obtained are in agreement and suggest the possibility of substitution of phosphate groups for silicate groups in the hydroxyapatite structure when introducing different sources of silica, tetraethoxysilane and sodium silicate, in the reaction mixture. Growth in the amount of silicon in Si-HA results in the increase in the thermal stability of the samples. The greatest mass loss occurs at temperatures in the range of 25-400 Β°Π‘ that is caused by the removal of the crystallization and adsorption water and volatile impurities. It is shown that the modified apatites are of imperfect structure and crystallize in a nanocrystalline state
Evaluation of the occupational risk of dock engineer of the seaport in Saint-Petersburg city
The aim of the study is assessment of harmful factors affecting the dock engineerβs health basing on the models of evaluation of the occupational risk to develop preventive measures in following.Π¦Π΅Π»ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΡΠ²Π»ΡΠ΅ΡΡΡ ΠΎΡΠ΅Π½ΠΊΠ° Π²Π»ΠΈΡΠ½ΠΈΡ Π²ΡΠ΅Π΄Π½ΡΡ
ΡΠ°ΠΊΡΠΎΡΠΎΠ² Π½Π° Π·Π΄ΠΎΡΠΎΠ²ΡΠ΅ Π΄ΠΎΠΊΠ΅ΡΠΎΠ² β ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·Π°ΡΠΎΡΠΎΠ² Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΡ ΠΌΠΎΠ΄Π΅Π»Π΅ΠΉ ΠΏΡΠΎΡΠ΅ΡΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΡΠΈΡΠΊΠ° Π΄Π»Ρ ΠΏΠΎΡΠ»Π΅Π΄ΡΡΡΠ΅ΠΉ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΏΡΠΎΡΠΈΠ»Π°ΠΊΡΠΈΡΠ΅ΡΠΊΠΈΡ
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