Experimental research and the numerical simulation of the non-standard pump for the flow-circulation type reactor

The paper shows the results of the experimental measurements and the numerical simulation of the flow-circulation type reactor pump main characteristics. The mathematical model based on Navier-Stokes equations and standard k-epsilon turbulence model was used for the pump CFD simulation. The pump power consumption was calculated by the proposed CFD post-processing method. It is found that the simulation error of the proposed method is not more than 2.9%. The obtained results include the regression equations of the pump full pressure, the pump feed and the power consumption at the pump cross-points. © 2019 IOP Publishing Ltd. All rights reserved

RESEARCH OF THE HYDRODYNAMIC OPERATION MODES OF A HIGH-SPEED SEDIMENTATION CENTRIFUGE

Two hydrodynamic regimes of high-speed sedimentation centrifuge were found. Laminar one is characterized by sedimentation of a solid phase and a liquid phase infinite mixing path. Turbulent is characterized by axial and radial pulsations of a liquid phase and decreasing of sedimentation efficiency

Restoration of the Genus <i>Paraunisaccoides</i> Martin, 1973 (Digenea: Haploporidae) and Description of <i>P. elegans</i> n. sp. and <i>Unisaccus halongi</i> n. sp. from Mugilid Fish in Vietnam

We restore the genus Paraunisaccoides (Haploporidae), synonymised earlier with the genus Skrjabinolecithum. Adult worms, detected in Vietnamese mullet fish, were highly similar to trematodes described as P. lobolecithum via digestive and genital system structures and relative organ arrangement. Differences are expressed as absence and presence of pads on the hermaphrodite duct, respectively, and the disjunction of some metric parameter values, namely body, ovary and eggs. Ribosomal DNA sequences, based on the phylogenetic analysis of Haploporidae, indicates that new worms represent a sister clade to Unisaccus tonkini. Genetic divergence between new worms and Skrjabinolecithum species can be interpreted as intergeneric. Based on morphological and molecular data, we recognise Paraunisaccoides as a valid genus within Waretrematinae and worms from Vietnam as a new species of this genus, P. elegans n. sp. Other worms detected in Vietnamese mugilids are morphologically similar to representatives of Paraunisaccoides и Skrjabinolecithum. However, molecular-based phylogenetic analysis showed that these trematodes are closely related to Unisaccus tonkini; the genetic divergence between them is at the interspecific level, despite considerable differences in vitellarium structure as intergeneric character. Accepting the priority of molecular results, we include these new worms into the genus Unisaccus as new species, Unisaccus halongi n. sp

A thermophilic L-lactic acid producer of high optical purity: isolation and identification

Biodegradable polymers, specifically polylactide, are an important part of food packaging and medical devices. Microbiological synthesis uses cheap renewable raw materials and industrial waste to produce a high yield of lactic acid, the monomer of polylactide. This method needs new effective lactic acid producing strains, e.g., thermophilic bacteria. The research involved thermophilic bacterial strains isolated from soil and compost samples. Their ability to produce organic acids and extracellular enzymes was tested using the method of high-performance liquid chromatography (HPLC) and microbiological tests respectively. The real-time polymerase chain reaction method (PCR) detected L-lactate dehydrogenase structural genes of L-lactate dehydrogenase of Bacillaceae. Strain T7.1 was fermented using glucose and yeast extract as carbon and nitrogen sources, respectively. The optical purity of lactic acid was evaluated using quantitative gas chromatography on a chiral column to separate lactate isomers. The molecular genetic analysis of the 16S rRNA gene sequence was applied to identify strain T7.1. The chromatographic analysis proved that 10 out of 13 isolated thermophilic strains were effective lactic acid producers. They demonstrated proteolytic, amylolytic, or cellulase activities. During the fermentation, strain T7.1 produced 81 g/L of lactic acid with a peak productivity at 1.58 g/(L·h). The optical purity of the product exceeded 99.9% L-lactate. The genetic analysis identified strain T7.1 as Weizmannia coagulans (Bacillus coagulans). The research revealed a promising thermophilic producer of optically pure L-lactic acid. Further research is needed to optimize the cultivation conditions, design an effective and cheap nutrient medium, and develop engineering and technological solutions to increase the yield