Measurement and modelling of static dielectric constants of aqueous solutions of methanol, ethanol and acetic acid at T=293.15K and 91.3kPa

Mohsen-Nia, M.; Amiri, Hamid

doi:10.1016/j.jct.2012.08.009

Cited by 26 publications

(19 citation statements)

References 32 publications

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“…To match the solvent polarity of 70% ethanol in water, methanol was chosen as solvent for LCMS analysis. The dielectric constant which reflects solvation power of 100% methanol was reported to be at 33.0 ε, while the respective value of 70% ethanol was 33.5 ε [ 20 ]. Further, comparable total phenol contents were obtained from extraction of propolis using methanol and water/ethanol [ 21 ].…”

Section: Resultsmentioning

confidence: 99%

Chemical Profile of Launaea nudicaulis Ethanolic Extract and Its Antidiabetic Effect in Streptozotocin-Induced Rats

et al. 2021

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Launaea nudicaulis is used in folk medicine worldwide to treat several diseases. The present study aimed to assess the antidiabetic activity of L. nudicaulis ethanolic extract and its effect on diabetic complications in streptozotocin-induced hyperglycemic rats. The extract was orally administrated at 250 and 500 mg/kg/day for 5-weeks and compared to glibenclamide as a reference drug at a dose of 5 mg/kg/day. Administration of the extract exhibited a potential hypoglycemic effect manifested by a significant depletion of serum blood glucose concurrent with a significant elevation in serum insulin secretion. After 5-weeks, extract at 250 and 500 mg/kg/day decreased blood glucose levels by about 53.8 and 68.1%, respectively, compared to the initial values (p ≤ 0.05). The extract at the two dosages prevented weight loss of rats from the 2nd week till the end of the experiment, compared to diabetic control rats. The extract further exhibited marked improvement in diabetic complications including liver, kidney and testis performance, oxidative stress, and relative weight of vital organs, with respect to diabetic control. Histopathological examinations confirmed the previous biochemical analysis, where the extract showed a protective effect on the pancreas, liver, kidney, and testis that degenerated in diabetic control rats. To characterize extract composition, UPLC-ESI–qTOF-MS identified 85 chromatographic peaks belonging to flavonoids, phenolics, acyl glycerols, nitrogenous compounds, and fatty acids, with four novel phenolics reported. The potential anti-diabetic effect warrants its inclusion in further studies and or isolation of the main bioactive agent(s).

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Section: Resultsmentioning

confidence: 99%

Chemical Profile of Launaea nudicaulis Ethanolic Extract and Its Antidiabetic Effect in Streptozotocin-Induced Rats

et al. 2021

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“…Non-covalent molecular interactions are particularly influenced by the solvent exchange. EtOH has a much lower relative permittivity than water, which influences electrostatic interactions [ 13 ]. In addition, water interacts much stronger with the nonpolar solvent than with the proteins [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Ethanol on the Textural Properties of Whey Protein and Egg White Protein Hydrogels during Water-Ethanol Solvent Exchange

et al. 2020

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This study aims at investigating the effect of ethanol (EtOH) on the textural properties of whey protein and egg white protein hydrogels. The hydrogels were produced by thermally induced gel formation of aqueous protein solutions. The water contained in the gel network was subsequently exchanged by EtOH to assess structural changes upon exposure of hydrogels to ethanolic aqueous phases. The textural properties of the hydrogel and alcogel samples were analyzed by uniaxial compression tests. For both protein sources, the hardness increased exponentially when pH and EtOH concentration were increased. This increase correlated with a shrinkage of the gel samples. The gel texture was found to be elastic at low EtOH concentrations and became stiff and hard at higher EtOH concentrations. It was found that the solvent exchange influences the ion concentration within the gels and, therefore, the interactions between molecules in the gel structure. Non-covalent bonds were identified as substantially responsible for the gel structure.

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“…To explain the discharge phenomenon above, the effects of the water conductivity on corona inception characteristics were analysed from the perspective of relative permittivity. The relationship between the relative permittivity of water and the amount of NaCl is shown in (3) [23, 24]

ε = ε_{0} false(1 - 6.6 y false)

where ɛ is the relative permittivity of water with NaCl, ɛ 0 is the relative permittivity of pure water, and y is the amount of NaCl dissolved in water, and its unit is mol/l [22].…”

Section: Experimental Results and Analysismentioning

confidence: 99%

Section: Effect Of Conductivity Of Water Droplets On Corona Inceptionmentioning

confidence: 99%

Influencing of water droplets on corona inception characteristics of composite insulator recorded by UV imager

Lü

Niu

Wang

et al. 2020

IET Science, Measurement &Amp; Technology

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Water droplets on the surface of insulators can distort the electric field and cause the generation of surface partial discharge or flashover. In this study, the inception and the development of surface partial discharges on a 110 kV composite insulator were evaluated by using a solar-blind ultraviolet imager. Several experiments were conducted by using water droplets differing in volume, conductivity, and position on an insulator housing. The results showed that the corona inception voltage decreases with the increasing volume of the water droplets. The relative permittivity of the water droplet decreases with the increase of the conductivity and then reduces the electric field intensity and increases the corona inception voltage. Installing the grading ring can increase the value of the corona inception voltage by 38% at most. To investigate the influence of the water droplets on the corona inception characteristics of the insulator, the sheath and shed models were proposed according to the feature of the electric field distribution. By changing the parameters of the water droplets, the corona inception voltage, discharge position, and electric field were analysed. Furthermore, the flashover voltage of the water droplets is influenced by its conductivity, while the corona inception voltage by its relative permittivity.

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Measurement and modelling of static dielectric constants of aqueous solutions of methanol, ethanol and acetic acid at T=293.15K and 91.3kPa

Cited by 26 publications

References 32 publications

Chemical Profile of Launaea nudicaulis Ethanolic Extract and Its Antidiabetic Effect in Streptozotocin-Induced Rats

Chemical Profile of Launaea nudicaulis Ethanolic Extract and Its Antidiabetic Effect in Streptozotocin-Induced Rats

Effect of Ethanol on the Textural Properties of Whey Protein and Egg White Protein Hydrogels during Water-Ethanol Solvent Exchange

Influencing of water droplets on corona inception characteristics of composite insulator recorded by UV imager

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