MODIFICATION OF CALCIUM PHOSPHATE FOAM CERAMICS WITH BIOAPATITE IN SBF SOLUTION

Получена многофазная кальцийфосфатная пенокерамика, представленная Д -трикальцийфосфатом (65 %) и Д -пирофосфатом кальция (25 %), включающая гидроксиапатит ( 5 %) и а -трикальцийфосфат ( 5 %), пористостью 60 - 64 % со сквозной архитектурой пенополиуретана. Нанесение слоя гидроксиапатита приводило к увеличению содержания гидроксиапатита до 25 %, а -трикальцийфосфата до 40 %, и повышению статической прочности до 0,03 МПа при снижении пористости до 49 %. Нанесение второго слоя гидроксиапатита способствовало повышению содержания гидроксиапатита до 40 %, статическая прочность достигала 0,05 МПа при пористости 40%. Формирование биоапатита в виде слоя «пеносфер» размером от 2 до 10 мкм происходило в процессе модифицирования всех видов пенокерамики в растворе SBF в течение 21 - 28 суток. Модифицированная кальцийфосфатная пенокерамика, обогащенная а -трикальцийфосфатом и гидроксиапатитом, характеризовалась максимальной статической прочностью 0,08 МПа при пористости 38%. The multiphase calcium phosphate foam ceramics, represented by р -tricalcium phosphate (65 %) and р -calcium pyrophosphate (25 %), including hydroxyapatite (5 %) and а -tricalcium phosphate (5%), with 60 - 64% porosity and a through architecture of polyurethane foam was obtained. The application of a layer of hydroxyapatite led to an increase in the content of hydroxyapatite to 25 %, а -tricalcium phosphate to 40%, and an increase in static strength to 0,03 MPa with a decrease in porosity to 49%. The application of the second layer of hydroxyapatite promoted an increase in the content of hydroxyapatite to 40%, the static strength reached 0,05 MPa at a porosity 40 %. The bioapatite formation in the shape of «foam spheres» with a size from 2 to 10 pm occurred in the process of modifying all types of foam ceramics in a SBF solution during 21 - 28 days. The modified calcium phosphate foam ceramics enriched with а -tricalcium phosphate and hydroxyapatite, was characterized by the maximum static strength 0,08 MPa at a porosity 38 %.

Static Strength Analysis of Meat Grinder Frame

Meat is one of the agricultural commodities needed to meet protein needs, because meat contains high quality protein, which is able to contribute complete essential amino acids. The purpose of this paper is to design, analyze the static strength of the frame based on theoretical calculations and simulations on solidwork 2018 software. This machine consists of a frame, reservoir, grinding shaft, transmission, and electric motor. The results of the design obtained a Meat Grinding Machine with Length: 610 mm, Width: 500 mm and Height: 750 mm. The material used is 2024-O Alloy with a modulus of elasticity of 72,400 N/mm2. The load force obtained is 576.32 N. And the value from the analysis is the displacement value of 0.174 mm and for theoretical calculations, the displacement value is 0.176 mm. So, the value of the percentage error is 1.176%. For the von Mises value of 68,970 MPa, and for calculations based on the theory, the von Mises value is 52,499 MPa. So, the value of the error percentage is 0.238%. And for the value of the safety factor obtained a value of 1,087, and for calculations based on the theory, the value of the safety factor is 1.428. So, the value of the error percentage is 0.313%.

Dependence of static strength of large single crystals of synthetic diamond type and Ib octahedral habit after heat treatment on their size

This article focuses on the problem of using large single crystals of type Ib synthetic diamond in single crystal and drilling tools. According to the literature review for the use of large diamonds in drilling equipment relevant conditions. The is shown possible negative effects of the temperature load on the diamond single crystal. The is presented developed technique for estimating the static strength of large diamond single crystals. It has been shown that microcrystals in the form of octahedra and cubes are formed as a result of heat treatment on the surface of synthetic diamond single crystals. The results of studies of the strength of large single crystals of synthetic diamonds of millimeter size are shown. In contrast to the classical approach, when IIb crystals are used for the production of drilling equipment, we present Ib crystals because they are closer to natural diamond in terms of physical and mechanical properties. The static strength criterion was used to assess the strength. It has been shown that crystals with a size of 1000 ... 1100 μm have a higher value of static strength than crystals with a size of 1200 μm and larger.

Characteristics of diatomite-alginate-Fe3O4 composite as a phosphate adsorbent

Technological approaches to the use of diatomaceous earth as a raw material for the creation of composite adsorbents for wastewater treatment from phosphate ions are analysed. It is shown that the developed surface of diatomite can be used to create a granular adsorbent, and iron (III) oxides (magnetite, goethite, lepidocrocite, ferrihydrite, hematite and goethite) are environmentally safe, cheap, economically feasible modifiers. Emphasis is placed on the possibility of obtaining magnetic granules due to the formation of magnetite. The use of the deposition method for the formation of the applied granular adsorbent is proposed. The influence of diatomite concentration on the static strength of granules was established. It is determined that the diameter of the nozzle is also an important factor. The selected technical solutions are aimed at solving the problems of granule hardening and ensuring high adsorption activity. Experimental studies of the synthesis and granulation of the composite adsorbent alginate - diatomaceous earth - magnetite have shown that an increase in the content of diatomaceous earth leads to a natural increase in the size of the granules. When increasing the diameter of the nozzle from 1.5 mm to 3.5 mm, for example, the size of the granules 1.5-4.0 (dc = 1.5 mm), 2.0-5.0 mm (dc = 3.0 mm) and 2.5-5.0 mm (dc = 3.5 mm). The diatomaceous earth content of more than 20% does not allow to carry out high-quality granulation on the experimental installation due to the increase in the viscosity of the suspension. The relationship between the size of gel granules and dried. The process of application of the active magnetic phase of the adsorbent is investigated. The dependence of the quality of the granulation process on the solid phase content is established. The measured static strength of the adsorbent granules is in the range of 17 - 25 kPa. It is established that the composite adsorbent with the applied layer of magnetite has magnetic properties. The adsorption of PO43- anions from aqueous solutions was studied. For the adsorbent alginate - diatomite and alginate - diatomite - Fe3O4 - the adsorption capacity is 4 and 9 mg PO43- / g, respectively. The obtained composite adsorbents have a set of functional properties that are promising for use in modern water purification and purification systems.