Countercurrent extraction with back-mixing - Evaluation of parameters

1978 ◽  
Vol 43 (10) ◽  
pp. 2682-2706 ◽  
Author(s):  
Anna Slavíčková ◽  
Georgi Angelov ◽  
Aleš Heyberger ◽  
Jaroslav Procházka
Keyword(s):  
Countercurrent Extraction ◽  
Evaluation Of Parameters ◽  
Back Mixing

Comparative assessment of average clinical smile parameters in male and female patients with orthognathic occlusion

2020 ◽  
Vol 25 (2) ◽  
pp. 121-126
Author(s):  
V. G. Galonsky ◽  
N. V. Tarasova ◽  
V. V. Aliamovskii ◽  
I. S. Leonovich
Keyword(s):  
Sexual Dimorphism ◽  
Male And Female ◽  
Young Males ◽  
Young Females ◽  
Female Patients ◽  
Evaluation Of Parameters ◽  
Distinguishing Features ◽  
Vertical Size ◽  
Relative Concept ◽  
The Ideal

Relevance. Separate issues in anthropomorphic sizes of relative norm of the ideal smile, its qualitative and qualitative parameters have not been addressed to sufficiently and are not properly reflected in scientific literature.Purpose. To determine distinguishing features in average smile parameters of the smile in male and female patients with orthognathic occlusion.Materials and methods. A clinical and anthropometric evaluation of parameters in main smile types was carried out for 150 young males and 150 young females aged 19-24 who had identical physiological development parameters.Results. It has been revealed that occurrence frequency of main smile types in patients with orthognathic occlusion has pronounced signs of sexual dimorphism which in over one half of the cases lies in predominance of the incisal smile type in males (52.7%) and the fascial type in females (55.3%). Occurence frequency of the cervical smile type totaled 25% among the studied patients of both genders. Average vertical size parameters in the incisal smile lies within the diapason of 3.91-4.91mm with surpassing by 1mm in males. Analogical data for the fascial smile type form the diapason of 6.21-6.73mm with surpassing by 0.52mm in females. The cervical smile type is characterised by larger vertical size forming the diapason of 7.94-8.91mm with surpassing by 0.97mm in males.Conclusion. The results of the study have shown that the “beautiful and ideal smile” is a relative concept having varied anthropometric characteristics and pronounced signs of sexual dimorphism lying in a broad spectrum of the dentofacial system norm notion with specific vectors for individual morphological deviations.

EVALUATION OF PARAMETERS THAT AFFECT MINIMUM MISCIBILITY PRESSURE DURING GAS INJECTION PROCESSES.

2017 ◽  
Vol 5 (2) ◽  
pp. 165-173
Author(s):  
IzuwaNkemakolam C. ◽  
◽  
NwabiaFrancis N. ◽  
OkoliNnanna O. ◽  
NwukoEjike S. ◽  
...  
Keyword(s):  
Gas Injection ◽  
Minimum Miscibility Pressure ◽  
Evaluation Of Parameters

Studies on extraction V. Determination of back-mixing and efficiency of stagewise extractors

1966 ◽  
Vol 31 (4) ◽  
pp. 1695-1711 ◽  
Author(s):  
F. Souhrada ◽  
J. Procházka ◽  
J. Landau
Keyword(s):  
Back Mixing

An experimental study of gas phase back mixing under the counter-current gas-liquid flow on a vertical expanded metal sheet packing by static tracer technique

1980 ◽  
Vol 45 (1) ◽  
pp. 214-221
Author(s):  
Jan Červenka ◽  
Mirko Endršt ◽  
Václav Kolář
Keyword(s):  
Gas Phase ◽  
Flow Model ◽  
Plug Flow ◽  
Packed Bed ◽  
Metal Sheet ◽  
Concentration Profiles ◽  
Expanded Metal ◽  
Gas Liquid Flow ◽  
Counter Current ◽  
Back Mixing

Gas phase back mixing has been measured in a column packed with vertical expanded metal sheet under the counter-current flow of gas and liquid by the static method using a tracer. The observed experimental concentration profiles has not confirmed our earlier proposed model of back mixing, based on the concentration profiles in absorption runs. These profiles do not even conform with the axially dispersed plug flow model currently used to describe axial mixing in packed bed columns. The concentration profiles may be described by a combination of the axially dispersed plug flow model with back flow.

Systematic errors in equilibrium composition of ternary liquid-liquid systems and their effect on the calculated number of theoretical stages of countercurrent extraction

1988 ◽  
Vol 53 (6) ◽  
pp. 1172-1180
Author(s):  
Ján Dojčanský ◽  
Soňa Bafrncová ◽  
Július Surový
Keyword(s):  
Equilibrium Composition ◽  
Systematic Errors ◽  
Liquid Equilibrium ◽  
Countercurrent Extraction ◽  
Liquid Systems ◽  
Equilibrium Concentrations ◽  
Line Slope ◽  
Tie Line ◽  
Calculated Number

The influence of magnitude of systematic errors in the determination of ternary liquid-liquid equilibrium concentrations on the accuracy of the calculated number of theoretical stages of countercurrent extraction is evaluated on using five hypothetical systems differing in the extent of mutual solubility of components, tie-line slope, and type of binodal curve.

The effect of systematic errors of the equilibrium distribution concentrations on the number of stages of countercurrent extraction with various consumption of extractant

1989 ◽  
Vol 54 (4) ◽  
pp. 981-989
Author(s):  
Ján Dojčanský ◽  
Soňa Bafrncová ◽  
Július Surový
Keyword(s):  
Equilibrium Distribution ◽  
Systematic Errors ◽  
Mutual Solubility ◽  
Operating Conditions ◽  
Liquid Equilibrium ◽  
Countercurrent Extraction ◽  
Absolute Deviation ◽  
Line Slope ◽  
Tie Line ◽  
Calculated Number

On using five hypothetical systems differing in the extent of mutual solubility of components, tie-line slope, and type of binodal curve, the effect is evaluated of systematic errors in the form of absolute deviation in the liquid-liquid equilibrium distribution concentrations on the accuracy of calculated number of theoretical stages of isothermal countercurrent extraction under various operating conditions.

Microwave Assisted Multi-Stage Countercurrent Extraction of Dihydromyricetin from Ampelopsis grossedentataa

2011 ◽  
Vol 7 (4) ◽  
Author(s):  
Wei Li ◽  
Cheng Zheng ◽  
Jian Zhao ◽  
Zhengxiang Ning
Keyword(s):  
Extraction Efficiency ◽  
Extraction Process ◽  
Extraction Time ◽  
Countercurrent Extraction ◽  
Bioactive Substances ◽  
Extraction Solvent ◽  
Microwave Assisted ◽  
Multi Stage ◽  
The Matrix ◽  
Substantial Concentration

A novel microwave assisted multi-stage countercurrent extraction (MAMCE) technique was developed for the extraction of dihydromyricetin from Chinese rattan tea, Ampelopsis grossedentata. The technique combined the advantages of microwave heating and dynamic multi-stage countercurrent extraction and achieved marked improvement in extraction efficiency over microwave assisted batch extraction. Analysis of dihydromyricetin concentrations in the solvent and matrix throughout the extraction process showed that by dividing the extraction into multiple stages and exchanging of solvents between stages, steady and substantial concentration gradients were established between the matrix and solvent, thus enabling the achievement of high extraction efficiency. The yield of dihydromyricetin was significantly affected by temperature, pH, solvent/material ratio and extraction time, and optimal extraction conditions were found to be 80-100°C, at acidic pH with a solvent/material ratio of 25-30 to 1 and extraction time of 5-10 min. With the high extraction efficiency and low usage of extraction solvent, MAMCE could prove to be a promising extraction technique which can be applied to the extraction of dihydromyricentin and other bioactive substances from natural materials.

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