Mathematical modeling of the sedimentation process for determining the fractional composition of suspensions

Exceptional prospects for use in science, technology and industry are opened by highly dispersed powders (ultradispersed diamonds, nanoceramics, medicinal powders) and materials based on them. The properties of such materials depend on the particle size determined by sedimentation analysis. An equation is proposed for processing sedimentation analysis data, which does not depend on the size distribution law of polydisperse system particles, and is used to describe the distribution functions of particles with radii for clay suspensions. A program in the Microsoft Visual Basic for Applications (VBA) language has been created for calculating the fractional composition of suspensions according to the proposed equation; the correctness of its operation on a model system has been checked and confirmed. Experimental research has confirmed that the use of the developed program and the "Search for a solution" add-on for the MS Excel environment makes it possible to determine the fractional composition of suspensions. It has been proven that the proposed method can be used to analyze polydisperse systems. It has been found that for the suspensions under consideration, as containing 25 fractions, it is possible to determine the integral curve of the distribution of the masses of the particles of the dispersed phase along the radii. This allows to assert the possibility of using the proposed equation for processing sedimentation analysis data, which does not depend on the law of mass distribution of polydisperse system particles by size. Thus, there is reason to assert about the possibility of a reasonable determination of the fractional composition of any polydisperse systems. It is possible to obtain certain effects from the introduction of sedimentation analysis data processing according to the proposed equation in production, where the fractional composition of dispersed phases is regulated.

HÖVSAN AERASİYA STANSİYASINDA TEXNOLOJİ PROSES ZAMANI ƏMƏLƏ GƏLƏN İZAFİ LİLİN TƏDQİQİ

hovsan Aeration Station provides treatment and processing of wastewater in baku. The amount of annual sludge here reaches 2 million cubic meters. These sludges contain complex multicomponent substances of organic and mineral origin. Taking this into consideration, we analyzed surplus sludge that generated during the technological process at hovsan Aeration Station. The studied surplus sample is a substance that is thickened in the mechanical workshop of the station, and then the substances are dehydrated in a centrifuge. They consist of a complex polydisperse system. The study of surplus sludge formed during the technological process at hovsan aeration station revealed that the main component of sludge consists of organic substances. The mineralogical composition is dominated by silicon dioxide and magnesium calcite. Keywords: wastewater, surplus sludge, mineral service, organic matter

Milk as a Complex Multiphase Polydisperse System: Approaches for the Quantitative and Qualitative Analysis

Milk is a product that requires quality control at all stages of production: from the dairy farm, processing at the dairy plant to finished products. Milk is a complex multiphase polydisperse system, whose components not only determine the quality and price of raw milk, but also reflect the physiological state of the herd. Today’s production volumes and rates require simple, fast, cost-effective, and accurate analytical methods, and most manufacturers want to move away from methods that use reagents that increase analysis time and move to rapid analysis methods. The review presents methods for the rapid determination of the main components of milk, examines their advantages and disadvantages. Optical spectroscopy is a fast, non-destructive, precise, and reliable tool for determination of the main constituents and common adulterants in milk. While mid-infrared spectroscopy is a well-established off-line laboratory technique for the routine quality control of milk, near-infrared technologies provide relatively low-cost and robust solutions suitable for on-site and in-line applications on milking farms and dairy production facilities. Other techniques, discussed in this review, including Raman spectroscopy, atomic spectroscopy, molecular fluorescence spectroscopy, are also used for milk analysis but much less extensively. Acoustic methods are also suitable for non-destructive on-line analysis of milk. Acoustic characterization can provide information on fat content, particle size distribution of fat and proteins, changes in the biophysical properties of milk over time, the content of specific proteins and pollutants. The basic principles of ultrasonic techniques, including transmission, pulse-echo, interferometer, and microbalance approaches, are briefly described and milk parameters measured with their help, including frequency ranges and measurement accuracy, are given.

Aggregation Features of Monodisperse Palladium Nanoparticles Supported on g-Al2O3

The production of supported on γ-A12O3 palladium catalysts by colloidal solution deposition method have been improved. Influence of temperature on the structure and dispersion characteristics of supported nanosized palladium particles during catalyst preparation and activation was investigated. It has been shown that at temperatures below 300oC monodisperse particles palladium catalysts are stable. Further temperature increase leads to aggregation of monodisperse metal nanoparticles by the mechanism of reaction-limited aggregation (RLA) to form polydisperse system.