جستجوی مقالات مرتبط با کلیدواژه "گلیسرول" در نشریات گروه "فنی و مهندسی"

Due to the limited soil resources and population increase, the use of contaminated or problematic soil is inevitable. There are different methods to improve the geotechnical properties of clay soils. One of the ways is to stabilize the soil with stabilizers such as Portland cement and lime. Investigation of the combined effect of organic pollutants under the influence of stabilizers (Portland cement (I) and lime) on Kaolinite clay using modified Proctor and CBR experiments constitutes the present research framework. The maximum unit weight decreased with an increase in Anthracene content while its variations were strongly dependent to the Glycerol content. The maximum of dry unit weight and a minimum of optimum water content occurred at a glycerol content of 6%. Based on test results, it was found that the increase in strength of clean Kaolinite using 6% of Portland cement is equivalent to that of 30% lime. It was also found that the contaminants decrease the strength of kaolinite; however, both stabilizers increase it. The effect of Portland cement on the strength of the specimens contaminated with Anthracene was better than that of lime and the effect of Portland cement and lime on the improvement of samples contaminated with Glycerol was considerable.

The purpose of this study was to evaluate the effect of glycyrol (tri-dentate, GLY) and ethylenediamine (double- dentate clay, en) chelating agents on phase and morphology changes of spinel nanoparticles synthesized by sol-gel method. Characterization of samples was performed by X-ray diffraction (XRD) and field-emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray spectrometer (EDX). The results showed that both samples synthesized with GLY and en contain cubic spinel phase. The sample synthesized with ethylenediamine has a pyramidal morphology with particle size in the range of 20-25 nm whereas the specimen prepared with glycerol is spherical with particle size in the range of 20-25 nm. Finally, suggested mechanism for morphological changes of spniel nanoparticles was discussed.

Carbon dioxide (CO2) separation from flue gases as a green-house gas produced from the combustion of fossil fuels is one of the main concerns in controlling the green-house gas emissions. Among the various technologies employed for gas separation, membrane technology due to its many advantages has attracted more attentions. A new blend membranes were prepared by solution casting/solvent evaporation method from poly(ether-b-amide) (Pebax) – as a backbone structure – and glycerol as an additive in the membrane matrix. CO2 and N2 permeability rates were measured at pressures of 2-10 bar and temperature of 25 °C. Afterwards, the CO2/N2 gas permeation properties were determined. Moreover, the effect of different glycerol loadings (0-25 wt%) in the membrane matrix and also the effect of feed pressure on CO2 permeability and CO2/N2 selectivity were investigated. Morphological characteristics of the prepared membranes were determined by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) analyses. The achieved results showed that by addition of glycerol to Pebax matrix, CO2 permeability was decreased somewhat but the CO2/N2 selectivity was considerably increased. At pressure of 10 bar, CO2/N2 selectivity of the blend membrane with 15 wt% glycerol was 172% higher than that of pure Pebax, while the CO2 permeability declined only by about 23%. Therefore, the blend membrane containing 15 wt% glycerol with a good CO2 permeability and a high CO2/N2 selectivity was selected as the optimum membrane. The FE-SEM observations revealed the compatibility and homogeneity of glycerol in the Pebax matrix. The XRD analysis determined that the addition of glycerol decreases the membrane crystallinity and the d-spacing between the polymer chains. The DSC results revealed that the insertion of glycerol in the membrane structure decreased the glass transition temperature. The FTIR spectra showed no new absorption band except for those for the constituent species, which suggests a physical interaction between Pebax and glycerol.

In this research, wheat, corn and potato thermoplastic starch films were prepared through melt mixing method and the effect of starch type and glycerol plasticizer content on their tensile and moisture sorption properties was investigated. The results depicted that by increasing glycerol content at studied range, the tensile strength and elastic modulus of film of all three starch types decreased significantly, while their percentage of elongation at break first raised up to certain amount and then followed a decreasing trend. Also among three thermoplastic starches, potato thermoplastic starch films had the highest tensile strength and elastic modulus and the lowest percentage of elongation at break values due to having higher amount of amylopectin content than other two thermoplastic starches. For all of three thermoplastic starches, increasing glycerol content increased moisture absorption of films so that by increasing glycerol weight percentage from 25 to 35 , the moisture absorption of wheat, corn and potato thermoplastic starch films conditioned at relative humidity of 84% for 7days, increased from 26.8, 29.9 and 36.8 to 30.8, 34.6 and 41.7 respectively. Indeed at the same environment relative humidity and glycerol content, the potato thermoplastic starch films had higher moisture absorption than wheat and corn thermoplastic starch films. The data of moisture sorption isotherm curves for the three thermoplastic starch films was modeled by Peleg model. The obtained correlation coefficients explained the suitability of this model for prediction of changes of moisture absorption of films versus water activity.

Glycerol is a hydrocarbon compound and is considered an environmental organic pollutant. This paper presents the effect of different percentages of glycerol on the strength of soil and soil-cement mixtures. Compressive strength experiments were conducted on natural soil and soil-cement (with %3 and %6 cement) samples contaminated with different percentages (%3, %6 and %9) of glycerol. Results indicated that compressive strength of soil samples prepared with different percentages of glycerol decrease compare to natural soil while increasing compressive strength of soil-cement mixtures at low percentages (%3) of glycerol. Furthermore using higher percentages of glycerol (%6 and %9) caused decrease in the compressive strength for soil-cement mixtures