Rheological properties of wood/bacterial cellulose and chitin nano‐hydrogels as a function of concentration and their nano‐films properties

In this study, rheological properties of the Wood Cellulose NanoFibers (WCNF), Bacterial Cellulose NanoFibers (BCNF), and Chitin NanoFibers (ChNF) as well as physical properties of films prepared from each nano‐hydrogel were investigated. Each nano‐hydrogel was prepared in 2 concentrations of 0.5 and 1 wt% for rheological study. Rheological properties were measured using a rotational rheometer. The flow behaviour data were fitted with rheological models. Apparent viscosity was higher in higher concentrations of nano‐hydrogels. Herschel‐Bulkley model was the best model for flow behaviour data fitting. BCNF nano‐hydrogels had the highest hysteresis loop while WCNF nano‐hydrogels had the best structure recovery and lowest hysteresis loop. At LVE (Linear Viscoelastic Region), G′ (storage modulus) and G″ (loss modulus) had a constant value, but as strain increased their values decreased. Storage modulus was found to be greater than loss modulus in all samples during frequency sweep test. BCNF nano‐hydrogel showed the lowest frequency dependency. Chitin nanofilms had the highest elongation and stress value.     

Solvent extraction and separation of light rare earth elements (La,Pr and Nd) in the presence of lactic acid as a complexing agent by Cyanex 272 in kerosene and the effect of citric acid,acetic acid and Titriplex III as auxiliary agents

At present, the use of rare earth elements (REEs) has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to control high volumes of liquids with electrical load. With the aim of improving a separation technology that would be superior to the existing extraction systems, the extraction behaviors of La(III), Pr(III), and Nd(III) from an HCl medium with Cyanex 272 in the presence of the complexing agent lactic acid (HLac) and auxiliary agents citric acid (H₃Cit), acetic acid (HAc), and Titriplex III have been reported. The effect of pH and lactic acid concentration has been examined. The use of lactic acid as a complexing agent leading to a high extraction of REEs with Cyanex 272 at pH = 5 was compared with systems without lactic acid. The results show that the use of acetic acid along with lactic acid leads to an increase in the extraction percentage of LREEs. While use of citric acid and Titriplex III reduces the extraction percentage of LREEs. Finally, the presence of Titriplex III together with lactic acid could lead to an increase in the separation factor of Pr and Nd.     

A new method for comparing the transfer function of transformers in order to detect the location and amount of winding faults

Since the transfer function (TF) is an acknowledged method for detecting power transformer faults, introduction of a proper manner to compare these TFs is necessary. Although a lot of effort has been made, proposed methods are not reliable. This paper presents a new approach based on weight functions, compared with all other methods. This comparison shows that the weight function method is much more effective than the others.     

Formulation and characterization of alprazolam-loaded nanoliposomes: screening of process variables and optimizing characteristics using RSM

This research study aimed to develop a novel sustained release formulation of alprazolam that can also be used for transdermal delivery. This was carried out, for the first time, through encapsulation of alprazolam in nanoliposomes using ethanol injection. In order to obtain the best formulation, four process variables, including the solvent/nonsolvent volume ratio, phospholipid concentration, alprazolam concentration, and cholesterol content were considered as key factors. Response surface methodology (RSM) and a central composite design (CCD) model were used to investigate the effect of these factors on vesicle size (VS) and encapsulation efficiency (EE) as the major properties of nanoliposomes. Experimental data were statistically analyzed, and two significant quadratic models were developed to test the VS and EE responses. The findings indicate that alprazolam and phospholipid concentrations have a significant effect on the mean VS. However, EE was significantly affected by both the alprazolam and phospholipid concentrations and the cholesterol content. The optimized formulation for preparation of alprazolam-loaded nanoliposomes with appropriate VS and EE was suggested. Small unilamellar vesicles (SUVs), ranging in size from 50 to 100?nm were clearly observed in the transmission electron microscopy (TEM) images, which is appropriate for transdermal delivery of alprazolam. The study of the prepared nanoliposomes over 28 days at 4?°C confirmed the stability of the formulations containing cholesterol. The results of an in vitro release study of alprazolam-loaded nanoliposomes in phosphate buffered saline (PBS), pH 7.4 for 24?h at 37?°C using dialysis, indicated the sustained release of alprazolam due to encapsulation.     

Solvent extraction and separation of light rare earth elements (La,Pr and Nd) in the presence of lactic acid as a complexing agent by Cyanex 272 in kerosene and the effect of citric acid,acetic acid and Titriplex Ⅲ as auxiliary agents

At present, the use of rare earth elements(REEs) has become an inevitable necessity in many modern industries. In general, liquid extraction is the best commercial method for extracting REEs due to its ability to control high volumes of liquids with electrical load. With the aim of improving a separation technology that would be superior to the existing extraction systems, the extraction behaviors of La(Ⅲ),Pr(Ⅲ), and Nd(Ⅲ) from an HCI medium with Cyanex 272 in the presence of the complexing agent lactic acid(HLac) and auxiliary agents citric acid(H_3 Cit), acetic acid(HAc), and Titriplex Ⅲ have been reported.The effect of pH and lactic acid concentration has been examined. The use of lactic acid as a complexing agent leading to a high extraction of REEs with Cyanex 272 at pH = 5 was compared with systems without lactic acid. The results show that the use of acetic acid along with lactic acid leads to an increase in the extraction percentage of LREEs. While use of citric acid and Titriplex Ⅲ reduces the extraction percentage of LREEs. Finally, the presence of Titriplex Ⅲ together with lactic acid could lead to an increase in the separation factor of Pr and Nd.