scholarly journals INVESTIGATION OF RHEOLOGICAL PROPERTIES OF HYDROXYAPATITE AND FLUORAPATITE IN COLLOIDAL STATE

Author(s):  
Екатерина Анатольевна Богданова ◽  
Владимир Михайлович Скачков

В статье обсуждается возможность практического применения суспензии гидроксиапатита и фторапатита в качестве компонентов лекарственных средств, фармацевтических композиций и биоматериалов. С использованием физикохимических методов анализа оценены их вязкость, плотность и степень дисперсности. Определены концентрационные интервалы, в которых исследуемые системы обладают свойствами, необходимыми для создания фармацевтических композиций и биоматериалов. Биологическая активность апатитов во многом зависит от степени дисперсности и проявляется тем больше, чем меньше размер их частиц, а полученные в данной работе наночастицы гидроксиапатита и фторапатита в суспензиях имеют размер частиц порядка менее 100 нм, и, следовательно, реологические свойства у них проявятся наиболее полно. The article discusses the possibility of practical application of a suspension of hydroxyapatite and fluorapatite as components of medicines, pharmaceutical compositions, and biomaterials. Their viscosity, density and degree of dispersion were estimated by using the physical and chemical analysis methods. The concentration intervals in which the studied systems have the properties necessary for creating pharmaceutical compositions and biomaterials are determined. The biological activity of apatites largely depends on the degree of dispersion and manifests itself the more, the smaller the size of their particles, and the obtained in this work nanoparticles of hydroxyapatite and fluorapatite in suspensions have a particle size of the order of less than 100 nm, and, consequently, their rheological properties will be most fully manifested.

2021 ◽  
Vol 3 (10(74)) ◽  
pp. 30-33
Author(s):  
N. Mamedova

The phase equilibrium of the Sb2Te3-HoTe3 system was studied by means of physical and chemical analysis methods DTA, RFA, MQA, as well as density and microhardness measurements, and its phase diagram was constructed. It has been determined that the Sb2Te3-HoTe3 system is a partial quasi-binary cross section of the ternary Bi-Ho-Te system. The system undergoes a process of eutectic equilibrium and peritectic transformation. In the Sb2Te3-HoTe3 system at room temperature, of the based Sb2Te3 solid solutions extend to 4.5 mol % and of the based HoTe3 solid solutions have practically not been established.


2010 ◽  
Vol 13 (3) ◽  
pp. 29-38
Author(s):  
Ha Bich Phan ◽  
Thach Ngoc Le

Coriandrum sativum L. belongs to the Apiaceae family, which is cultivated in Dong Nai province, in this paper its seed oil of was studied. The essential oil was extracted by hydrodistillation. We used two methods for activating of hydrodistillation: conventional heating and microwave irradiating. Its physical and chemical indexes were measured. The chemical composition of this oil was identified by GC/MS and quantified by GC/FID. Linalool (75.51-77.21 %), and geranyl acetate (15.64-12.79 %) were the main constituents of the oil which were obtained in 0,32-0.39 % yield. The biological activity of this oil was reported.


Soft Matter ◽  
2021 ◽  
Vol 17 (39) ◽  
pp. 8925-8936
Author(s):  
Heedong Yoon ◽  
Zachary R. Hinton ◽  
James Heinzman ◽  
Clarence E. Chase ◽  
Manesh Gopinadhan ◽  
...  

There is a clear correlation between pyrolysis time and the extensional properties of pitch. Chemical analysis shows an increase in aromatic species and a shift to higher molecular weight. We hypothesize that these results are important in understanding pitch spinnability.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Dianbin Su ◽  
Xin-Di Zhu ◽  
Yong Wang ◽  
Dong Li ◽  
Li-Jun Wang

Abstract Citrus fiber dispersion with different concentrations (5–25 g/kg) was treated by high-pressure homogenization (90 and 160 MPa) for two cycles. The particle size distribution, hydration properties of powders, morphology and rheological measurements were carried out to study the microstructure and rheological properties changes by high-pressure homogenization (HPH). In conclusion, the HPH can reduce the particle size of fiber, improve the water holding capacity and water binding capacity. Furthermore, fiber shape can be modified from globular cluster to flake-like slices, and tiny pores can be formed on the surface of citrus fiber. The apparent viscosity, storage modulus and loss modulus were increased by HPH whereas the activation energy was reduced. The Hershcel–Bulkley model, Carreau model and Power Law mode were selected to evaluate the rheological properties.


2003 ◽  
Vol 12 (1) ◽  
pp. 13-22 ◽  
Author(s):  
W. A. P. J. Premaratne ◽  
N. A. Rowson

An investigation has been carried out to study the mineralogical and chemical characteristics of beach sand deposits from Sri Lanka and application and optimisation of different magnetic separators (induced roll magnetic separator and disc magnetic separator) to improve the recovery of titanium from the deposit. Commercial grade titanium concentrates could be achieved employing both induced roll and disc magnetic separators. However, the titanium recovery increased greatly in the magnetic fraction with a titanium content of commercial grade (up to 63.9% TiO2) when paramagnetic titanium-bearing minerals were separated from beach sand using the disc magnetic separator. The results of the mineralogical and chemical analysis tests for the beach sand deposit indicated that 71% of beach sand was smaller than 355 μm in particle size and more than 99% of titanium content of the deposit was contained in this fraction.


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