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.

Comparative Analysis of anti-Shine- Dalgarno Function in Flavobacterium johnsoniae and Escherichia coli

The anti-Shine-Dalgarno (ASD) sequence of 16S rRNA is highly conserved across Bacteria, and yet usage of Shine-Dalgarno (SD) sequences in mRNA varies dramatically, depending on the lineage. Here, we compared the effects of ASD mutagenesis in Escherichia coli, a Gammaproteobacteria which commonly employs SD sequences, and Flavobacterium johnsoniae, a Bacteroidia which rarely does. In E. coli, 30S subunits carrying any single substitution at positions 1,535–1,539 confer dominant negative phenotypes, whereas subunits with mutations at positions 1,540–1,542 are sufficient to support cell growth. These data suggest that CCUCC (1,535–1,539) represents the functional core of the element in E. coli. In F. johnsoniae, deletion of three ribosomal RNA (rrn) operons slowed growth substantially, a phenotype largely rescued by a plasmid-borne copy of the rrn operon. Using this complementation system, we found that subunits with single mutations at positions 1,535–1,537 are as active as control subunits, in sharp contrast to the E. coli results. Moreover, subunits with quadruple substitution or complete replacement of the ASD retain substantial, albeit reduced, activity. Sedimentation analysis revealed that these mutant subunits are overrepresented in the subunit fractions and underrepresented in polysome fractions, suggesting some defect in 30S biogenesis and/or translation initiation. Nonetheless, our collective data indicate that the ASD plays a much smaller role in F. johnsoniae than in E. coli, consistent with SD usage in the two organisms.

Estimation features of winter bread wheat quality by the method of sedimentation analysis

It is known that the breeding process is in a great need for fast methods, working on minimal weights of experimental material and revealing the qualitative potential of the varieties. For this purpose, in order to get rid of unpromising numbers, the laboratory assessments widely use a sedimentation analysis, this type of analysis being the main one at the primary stages of breeding and when estimating winter wheat in the pre-harvesting period. The purpose of the current study was to identify the most valuable genotypes in seed plots by sedimentation analysis to optimize the breeding process of winter bread wheat for grain quality. The sedimentation index was estimated by the method using a 2% surfactant (SAS) solution of the sodium dodecyl sulfate (SDS) and 9.4% lactic acid. Gluten content and its quality, volumetric bread yield and falling number were assessed according to generally accepted methods. For the most accurate interpretation of the study results there has been used a one-way analysis of variance. The range of variation of the sedimentation index in the seed plot of CVT was 35–57 ml (2017); 50–83 ml (2018); 56–84 ml (2019); in KP-1 it was 44–95 ml (there were analyzed 945 samples); in KP-2 it was 50–94 ml (there were analyzed 100 samples). Inthe studied seed plot of CVT, which was laid fallow, 25 of 36 variety samples were very strong in quality; 7 ones were strong; 4 ones were medium; there were not identified any satisfactory and weak samples. As for the seed plot KP-2, 88 of 100 were very strong, 11 ones were strong and only one sample was average in quality. In the seed plot KP-1 480 of 945 were very strong (51%); 440 samples were strong (46%), and only 3% (25 pieces) were average in quality; there were not identified any satisfactory and weak samples.

Stabilization of oil-in-water emulsions via soy protein and soy soluble polysaccharide interactions

The stabilizing behaviour of soluble soy polysaccharide (SSPS) on acidified dispersions of soy protein isolate (SPI) and SPI-stabilized emulsions was studied. SPI and SSPS suspensions were characterized via light scattering, surface charge measurement, turbidity, sedimentation analysis, and light microscopy. At acidic pH (pH 6-3), it was found the addition of at least 0.25 wt% SSPS was required to stabilize 0.75 wt% SPI suspensions against aggregation and phase separation, likely via steric repulsion. The mechanism of SPI-SSPS interaction was shown to be electrostatic in nature by testing the effects of increased ionic strength of the suspensions. The stabilizing effect of SSPS on SPI was then applied to 5% oil-in-water emulsions. The presence of SSPS stabilized the emulsions against droplet size increases and phase separation over time. Overall, the results demonstrated that it was possible for SSPS to stabilize SPI suspensions and that SPI-SSPS interactions may be used as a tool to stabilize O/W emulsions.

Stabilization of oil-in-water emulsions via soy protein and soy soluble polysaccharide interactions

The stabilizing behaviour of soluble soy polysaccharide (SSPS) on acidified dispersions of soy protein isolate (SPI) and SPI-stabilized emulsions was studied. SPI and SSPS suspensions were characterized via light scattering, surface charge measurement, turbidity, sedimentation analysis, and light microscopy. At acidic pH (pH 6-3), it was found the addition of at least 0.25 wt% SSPS was required to stabilize 0.75 wt% SPI suspensions against aggregation and phase separation, likely via steric repulsion. The mechanism of SPI-SSPS interaction was shown to be electrostatic in nature by testing the effects of increased ionic strength of the suspensions. The stabilizing effect of SSPS on SPI was then applied to 5% oil-in-water emulsions. The presence of SSPS stabilized the emulsions against droplet size increases and phase separation over time. Overall, the results demonstrated that it was possible for SSPS to stabilize SPI suspensions and that SPI-SSPS interactions may be used as a tool to stabilize O/W emulsions.

SEDIMENTATION ANALYSIS OF THE DISPERSED PHASE DURING TREATMENT OF PHENOLIC WASTEWATER OF COKE-CHEMICAL PRODUCTION BY GLAUCONITE

Kinetic regularities of adsorption treatment of phenolic wastewater with glauconite have been revealed. It was found that glauconite at a dose of 2 g/dm3 in combination with a 0.1% solution of cationic flocculant, which provides removal of resinous substances up to 94% for 10 min and phenols up to 20% during 20 min. As a result, the MPC of phenols and resinous substances was achieved at the stage of mechanical treatment of effluents, which are then fed for biochemical processing into aeratanks, which is 415 mg/dm³ and 25 mg/dm3, respectively. The dispersed composition of sediments after treatment of industrial wastewater with glauconite was studied. It was found that the particle radii of the polydisperse system "liquid waste – glauconite" in combination with cationic flocculant were the largest and reached r = 537 mkm, which is twice the maximum polydisperse systems "liquid waste – glauconite" and "liquid waste – glauconite" with an anionic flocculant. Sedimentation analysis showed that the sedimentation time of the sediment decreased from 17 min to 6 min in the system "liquid waste – glauconite" in combination with cationic flocculant and formed a precipitate of loose flakes, which settled quickly. The introduction of a flotation plant with a dosage of natural glauconite 2 g/dm3 in combination with a 0.1% solution of cationic flocculant at industrial treatment facilities is proposed. Engineering solutions will improve the quality of wastewater supplied for coke quenching and will make it possible to transport and dispose of sludge after waste treatment with glauconite, which is planned to be used as a raw material for the manufacture of pavements in asphalt plants.