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Laboratory Investigation of the Effects of Sodium Chloride Concentration on Soil Water Retention Curve and Volumetric behavior Using an Unsaturated Automatic Oedometer
, M.Sc. Thesis Sharif University of Technology ; Sadeghi, Hamed (Supervisor)
Abstract
Laboratory studies to investigate the effects of different saline concentrations (such as sodium chloride or calcium chloride) on the soil water retention behavior of clayey soils and their volumetric changes have received much attention recently. However, many previous studies have investigated these effects in only one path of the SWRC (wetting or drying path) and the effects of saline concentration on hydraulic hysteresis have not been considered. In addition, researchers have frequently studied these effects on SWRC on clay samples, and little research has been done on collapsible soils. Therefore, the most important purpose of this study is to investigate the effects of increasing...
Transesterification of sunflower oil to biodiesel fuel utilizing a novel K2CO3/Talc catalyst: Process optimizations and kinetics investigations
, Article Industrial Crops and Products ; Volume 156 , 2020 ; Kazemeini, M ; Sadjadi, S ; Sharif University of Technology
Elsevier B.V
2020
Abstract
A novel efficient and cost-effective heterogeneous catalyst for the production of biodiesel from transesterification of sunflower oil was prepared through the impregnation of K2CO3 upon the Talc material. The physicochemical features of the catalyst were studied through several characterization analyses. The effect of the K2CO3 loading was investigated by comparing the catalytic activity of various prepared catalysts. Moreover, the effect of the calcination temperature upon the catalytic activity was examined. To maximize the yield of the produced biodiesel fuel, reaction variables such as the reaction time and temperature, catalyst concentration, and methanol: oil molar ratio were...
Simulation and performance improvement of cryogenic distillation column, using enhanced predictive Peng–Robinson equation of state
, Article Fluid Phase Equilibria ; Volume 489 , 2019 , Pages 117-130 ; 03783812 (ISSN) ; Bayat, M ; Afshin, H ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In this study, a cryogenic distillation column has been designed and simulated via a computer code based on the theta method of convergence. The required thermodynamic properties are determined from the enhanced predictive Peng-Robinson (E-PPR 78) equation of state which has a good accuracy in predicting the corresponding thermodynamic properties of natural gas components. The combined code of distillation column/equation of state has been verified with that of another study. In the present study, the results are achieved by the constant molar over-flow and inclusion of energy equations assumptions. In order to have more accuracy in the results, the energy equations were considered in the...
Optimization and characterization of tannic acid loaded niosomes for enhanced antibacterial and anti-biofilm activities
, Article Advanced Powder Technology ; 2020 ; Akbarzadeh, I ; Nourouzian, D ; Mirzaie, A ; Bakhshandeh, H ; Sharif University of Technology
Elsevier B.V
2020
Abstract
The purpose of this study was to prepare and characterize an optimized system of tannic acid-loaded niosomes as a potential carrier for antibacterial and anti-biofilm delivery. The niosomal formulation was optimized using response surface methodology (RSM). The effects of the molar ratio of surfactant to cholesterol, drug concentration, and molar ratio of Span 60 to Tween 60 on particle size and drug entrapment efficiency of the niosomal nanocarrier were studied. The optimized nanoparticles were characterized in terms of the morphology, in vitro release profile, and antibacterial properties. Moreover, Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC)...
Investigation of precursors concentration in spray solution on the optoelectronic properties of CuInSe2 thin films deposited by spray pyrolysis method
, Article Journal of Materials Science: Materials in Electronics ; 2020 ; Ghorashi, S. M. B ; Tajabadi, F ; Taghavinia, N ; Sharif University of Technology
Springer
2020
Abstract
Copper indium selenide CuInSe2(CISe) thin films were deposited by chemical spray pyrolysis (CSP) method of CuInS2(CIS) and subsequent selenization process. To study the effects of solution concentration, we prepared different precursors solution of CIS including different amount of indium salts from 0.025 to 0.100 M with In/Cu 1.25 and S/In 4. These results propose that solution concentration is critical for inflecting the morphological, optical, electrical, and electrochemical characteristics of solution-processed CISe films and device performance. The studied morphological properties of deposited samples were homogenous, crack-free with large grains in indium salt concentrations more than...
Investigation of precursors concentration in spray solution on the optoelectronic properties of CuInSe2 thin films deposited by spray pyrolysis method
, Article Journal of Materials Science: Materials in Electronics ; Volume 32, Issue 21 , 2021 , Pages 25748-25757 ; 09574522 (ISSN) ; Ghorashi, S. M. B ; Tajabadi, F ; Taghavinia, N ; Sharif University of Technology
Springer
2021
Abstract
Copper indium selenide CuInSe2(CISe) thin films were deposited by chemical spray pyrolysis (CSP) method of CuInS2(CIS) and subsequent selenization process. To study the effects of solution concentration, we prepared different precursors solution of CIS including different amount of indium salts from 0.025 to 0.100 M with In/Cu 1.25 and S/In 4. These results propose that solution concentration is critical for inflecting the morphological, optical, electrical, and electrochemical characteristics of solution-processed CISe films and device performance. The studied morphological properties of deposited samples were homogenous, crack-free with large grains in indium salt concentrations more than...
Hysteresis of soil water retention and shrinkage behaviour for various salt concentrations
, Article Geotechnique Letters ; Volume 11, Issue 1 , 2021 , Pages 21-29 ; 20452543 (ISSN) ; Nasiri, H ; Sharif University of Technology
ICE Publishing
2021
Abstract
Laboratory investigation on the influence of solute concentration on the soil water-retention curve (SWRC) and volumetric behaviour of expansive soils has received much attention in recent years due to increasing environmental pollution. However, most studies only considered applying wetting or drying path with almost no attention to hydraulic hysteresis. Furthermore, these studies have focused on examining expansive soils and only marginal effort has been devoted to collapsible soils. Therefore, the main objective of this study is to systematically explore the SWRC and shrinkage characteristics of an artificially made collapsible soil at various molar concentrations. The tests were...
Gel combustion synthesis of fluorine-doped tin oxide and its characteristics: applying D-optimal factorial design of experiment
, Article Bulletin of Materials Science ; Volume 42, Issue 3 , 2019 ; 02504707 (ISSN) ; Baghshahi, S ; Sarraf Mamoory, R ; Nemati, A ; Sharif University of Technology
Indian Academy of Sciences
2019
Abstract
Fluorine-doped tin oxide (FTO) nano-powders were synthesized by a gel combustion method. To analyse the effect of processing factors and their interactions and to achieve an equation for nano-powder particle size in terms of code factors, D-optimal factorial design was used. Stannous chloride penta-hydride, ammonium fluoride and citric acid were used to synthesize the FTO nano-powders. The structure, morphology and composition of the synthesized powders were characterized by X-ray diffraction, field emission scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. The results revealed the formation of homogenous FTO nano-powders with an average particle size of 20 nm...
Comparison of single and binary oxide sol-gel gas sensors based on titania
, Article Solid State Sciences ; Volume 10, Issue 7 , 2008 , Pages 884-893 ; 12932558 (ISSN) ; Fray, D. J ; Ghorbani, M ; Sharif University of Technology
Elsevier Masson SAS
2008
Abstract
A systematic comparison of single and binary metal oxides TiO2, TiO2-Ga2O3 and TiO2-Er2O3 thin film gas sensors with nanocrystalline and mesoporous microstructure, prepared by a new particulate sol-gel route, was conducted. The gas sensitivity was increased by introduction of Ga2O3 and Er2O3 into TiO2 film via two mechanisms, firstly through the inhibition of anatase-to-rutile transformation, since the anatase phase accommodates larger amounts of adsorbed oxygen, and secondly through the retardation of grain growth, since the higher surface area provides more active sites for gas molecule adsorption. The binary metal oxide gas sensors exhibited a remarkable response towards low...
Ambient-cured alkali-activated slag paste incorporating micro-silica as repair material: Effects of alkali activator solution on physical and mechanical properties
, Article Construction and Building Materials ; Volume 229 , 2019 ; 09500618 (ISSN) ; Zareei, A. R ; Shoaei, P ; Ameri, F ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this paper, the optimum alkali activator solution properties in alkali-activated pastes based on ground granulated blast furnace slag (GGBFS) and micro-silica (MS) were investigated. For this purpose, sodium hydroxide (NH) solutions with molarities of 8 M, 12 M, and 16 M were prepared and mixed with sodium silicate (NS) solutions at NS:NH ratios of 1.0, 2.5, and 4.0 to produce the final activator solution. Two sets of pastes were manufactured: (1) pastes based on GGBFS, and (2) pastes in which 10% by weight of GGBFS was replaced with MS. The fresh density increased with increasing NH molarity and NS:NH ratio; whereas, the final setting time reduced with an increase in the aforementioned...
Alkali-activated slag (AAS) paste: Correlation between durability and microstructural characteristics
, Article Construction and Building Materials ; 2020 ; Shariati, A ; Trung, N. T ; Shoaei, P ; Ameri, F ; Bahrami, N ; Narimani Zamanabadi, S ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This study was aimed at evaluating the effects of alkali activator solution and utilization of silica fume (SF) on durability and microstructural characteristics of alkali-activated ground granulated blast furnace slag (GGBFS) pastes. The pastes were activated with sodium silicate (SS) blended with NaOH (SH) solution with molar concentrations of 8 M, 12 M, and 16 M and SS:SH ratios of 1.0, 2.5, and 4.0. The same mixes were prepared with SF as partial replacement of GGBFS at a dosage of 10% by weight. The initial and final water absorption as well as the electrical resistivity of the specimens were measured. The optimal paste fabricated with 12 M NaOH solution and SS:SH ratio of 2.5 showed...
Alkali-activated slag (AAS) paste: Correlation between durability and microstructural characteristics
, Article Construction and Building Materials ; Volume 267 , 2021 ; 09500618 (ISSN) ; Shariati, A ; Trung, N. T ; Shoaei, P ; Ameri, F ; Bahrami, N ; Zamanabadi, S. N ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study was aimed at evaluating the effects of alkali activator solution and utilization of silica fume (SF) on durability and microstructural characteristics of alkali-activated ground granulated blast furnace slag (GGBFS) pastes. The pastes were activated with sodium silicate (SS) blended with NaOH (SH) solution with molar concentrations of 8 M, 12 M, and 16 M and SS:SH ratios of 1.0, 2.5, and 4.0. The same mixes were prepared with SF as partial replacement of GGBFS at a dosage of 10% by weight. The initial and final water absorption as well as the electrical resistivity of the specimens were measured. The optimal paste fabricated with 12 M NaOH solution and SS:SH ratio of 2.5 showed...