Hydrogen removal in circulating vacuum degasser under conditions of PJSC “NLMK”

For high­quality steel smelting, stage­by­stage production is required, which has a complex of metallurgical units capable for producing products with high performance properties and low content of harmful impurities. One of the harmful impurities is hydrogen, so it is important to limit its content in the metal. To ensure the specifed hydrogen content, the metal in the steel out­of­furnace treatment at Converter Shop No. 2 (CS­2) of PJSC “Novolipetsk Metallurgical Plant” (“NLMK”) is subjected to vacuum treatment in a circulating vacuum degasser. Despite the prevalence of circulating vacuum derassers, theoretically, mechanism of hydrogen removal in these metallurgical units has been insufciently studied. To increase efciency of hydrogen removal, theoretical calculations were performed to remove it from the metal. There are several mechanisms for hydrogen removing: direct transfer of hydrogen from metal to the surrounding space; formation of gas bubbles in metal and their direct ascent; nucleation of hydrogen bubbles at the border of refractory wall and metal; removal of hydrogen by metal blowing with neutral gas (argon). It is shown that the main ways of hydrogen removal in a circulating vacuum degasser are direct transfer of hydrogen from metal to the surrounding space and blowing of melt with transporting gas. In the CS­2 of PJSC “NLMK”, both ways are implemented at a circulating vacuum degasser. Vacuum pumps provide pressure in a vacuum chamber of less than 101.3 Pa (0.001 atm.). It promotes intensive removal of hydrogen from the metal surface. To ensure circulation of metal, transporting gas argon is supplied to the inlet pipe of the RH degasser, which also takes part in removal of dissolved gases by transferring hydrogen to neutral gas bubbles. Additionally, performed calculations have shown that the main way of degassing in conditions of CS­2 of PJSC “NLMK” is removal of hydrogen into the bubbles of carrier gas.

DEVELOPMENT AND VALIDATION OF HPLC METHOD FOR SIMULTANEOUS QUANTIFICATION OF VASICINE, GLYCYRRHIZIN AND PIPERINE IN POLY HERBAL COUGH SYRUP

Objective: The present study was undertaken to develop a rapid, simple, specific and economic high performance liquid chromatographic (HPLC) method has been developed, validated and used for simultaneous quantification of Vasicine, Glycyrrhizin and Piperine in poly herbal cough syrup Methods: An Agilent technologies 1200 Series quaternary pump combined with an Agilent 1200 series photo diode array detector (USA), an Agilent 1200 series vacuum degasser (USA) and an Agilent autosampler injector. Chromatographic separation was performed on a Hiber, prepacked column, C18, Size 250x 4.60 mm, 5µ maintained at 25 °C. PJ (solvent A) and HPLC grade Acetonitrile (solvent B). Results: The HPLC developed for quantization was simple, accurate and specific. The drug follows the beer’s lambert’s law in the concentration range of of Vasicine in concentration range 25–250 μg/ml, glycyrrhizin in concentration range 100–1000 μg/ml and Piperine in concentration range of 20–100μg/ml and exhibited good correlation coefficient and excellent mean recovery. Percentage RSD for precision and accuracy of the method was found to be less than 2%. Conclusion: The present standardization provides a specific and rapid tool in the herbal research, permitting to set quality specifications for identity, transparency and reproducibility of these Phytoconsituents in the herbal Cough syrup.

Pharmacokinetic Study and Optimal Formulation of New Anti-Parkinson Natural Compound Schisantherin A

Our recent studies showed that schisantherin A (StA) is a promising candidate for PD treatment, but the pharmacokinetic profile of StA is largely unknown. The effects of different formulations on the pharmacokinetics and bioavailability of StA were investigated by HPLC equipped with a vacuum degasser, a quaternary pump, a manual sampler, and an ultraviolet detector. The absolute bioavailability of StA in nanoemulsion formulation was significantly increased from 4.3% to 47.3%. To the best of our knowledge, this is the first report of absolute bioavailability for StA in rats and successful increase of bioavailability of StA by nanoemulsion formulation. The pharmacokinetic profiles of StA could be significantly improved by a safe nanoemulsion formulation. This study provides a successful example of advanced delivery system for improving the bioavailability of potential central nervous system (CNS) drug candidate with poor solubility. This novel approach could be an effective alternative solution to overcome the shortcomings of conventional poor drug delivery of CNS drugs. The results of present study not only indicate that StA has potential to be developed as a promising oral therapeutic agent for the management of PD but also shed light on novel way to improve bioavailability of PD drugs.

The Wear Mechanism Comparison between MgO-Based Chrome-Free Brick and MgO-Cr2O3 Brick in the Lower Part of RH Vacuum Degasser

The damage and improvement mechanism of rebonded MgO-Cr2O3 brick and MgO-ZrO2 brick used in the lower part of RH vacuum degasser were studied. The results show that the main damage of rebonded MgO-Cr2O3 brick is structure spalling because of the penetration of slag. MgO-ZrO2 brick has characteristics of high direct-bonding degree, small air permeability and making the viscosity of penetrated slag increased by means of ZrO2 absorbing CaO in slag to form CaZrO3 or ZrO2 solid solution, which make the degree of slag penetration decrease and improve the structure spalling resistance. MgO-ZrO2 brick has the defect of poor thermal shock resistance in use, the incorporation of MgO-rich spinel into MgO-ZrO2 brick significantly improved both thermal shock resistance and hot modulus of rupture because of the formation of eutectoid structure of grain-refining spinel and zirconia, which also improved structure spalling resistance because air permeability was decreased to 5% of MgO-ZrO2 brick