نتایج جستجو برای: solvent ratio
تعداد نتایج: 553282 فیلتر نتایج به سال:
It is unclear whether specific agent groups are associated with outcomes in cases of poisoning-induced out-of-hospital cardiac arrest (P-OHCA). The study population comprised cases of confirmed P-OHCA drawn from the national out-of-hospital cardiac arrest (OHCA) registry (2008-2013). Exposures were categorized into five groups according to the International Classification of Disease, 10th versi...
BACKGROUND Biobutanol production is still not economically competitive because of some principal drawbacks including high cost in feedstock consumption, low butanol concentration in the fermentation broth caused by severe product inhibition. An alternative fermentation mode is becoming an urgent requirement to solve these problems. Biobutanol production by absorbent fermentation with a renewabl...
The constraint in synthesis of ß-lactams by penicillin acylase is the hydrolysis of the activated acyl donor and the synthetic product. The thermodynamically controlled synthesis of ß-lactams deals with direct acylation of a nucleophile (6APA, 7-ACA or 7-ADCA) by free acids in acidic pH and high concentration of solvent to achieve good yield. On the other hand, the kinetically controlled synthe...
Mung bean (Vigna radiata) sprout is commonly consumed as a vegetable, while the coat of the germinated mung bean is a waste. In this paper, an ultrasound-assisted extraction method has been developed to extract natural antioxidants from the seed coat of mung bean. Several experimental parameters-which included ethanol concentration, solvent/material ratio, ultrasound extraction time, temperatur...
An ultrasound-assisted extraction (UAE) method was developed for the efficient extraction of natural antioxidants from the flowers of Jatropha integerrima. Four independent variables, including ethanol concentration, solvent/material ratio, ultrasound irradiation time and temperature were studied by single factor experiments. Then, the central composite rotatable design and response surface met...
Nanoparticles were obtained by nanoprecipitation and emulsion solvent evaporation (ESE) method. In the ESE method, size of particles depended on type concentration surfactant (in water phase) polymer organic phase). The best results with ionic surfactants, however, use such compounds may accelerate degradation process polymers. ratio (methylene chloride) to non-solvent (hexane) has a significan...
Dragon fruit peel can be utilized as a natural dye due to betacyanin content, redviolet pigment of betalain group. Betacyanin is unstable to temperature, oxygen, and light, consequently microencapsulation technology is required to maintain its stability. This study aims to determine microencapsulation efficiency of dragon fruit peel extract with variation of encapsulation ratio and to perceive ...
An efficient and environmental-friendly extraction method has been developed for extraction of ursolic acid (UA) from Hedyotis diffusa by using subcritical water extraction (SWE). The experiments were carried out at different particle sizes (20–100 mesh), extraction temperature (120–200 ◦C), extraction time (10–50 min), solvent/solid ratio (20–40 mL/g), and extraction pressure (0.6–3.0 MPa). Re...
The solvent extraction of neodymium, a rare earth metal, was studied with a continuous stirred vessel. One of the widely used extractants, 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A), diluted with kerosene was selected as an extracting organic solvent. First, the extraction equilibrium of neodymium between aqueous and organic phases was measured in a batch-wise experimental ru...
The current work concerns the optimization process of phenolic compounds solid liquid extraction from grape byproducts at high temperatures and short incubation times. The effect of five experimental parameters (solidliquid ratio, particle size, time, temperature and solvent mixture) mostly believed to affect the extraction process was undertaken. A first response surface methodology experiment...
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