Search for: phase-separation
Total 72 records
Porous Structured of Polystyrene by Phase Separation in Liquid Nitrogen for Immersed Solvent Supported µ-extraction of Polycyclic Aromatic Hydrocarbons, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib
Porous materials using polymers have been developed for a variety of industrial applications. These structures mostly contain well-aligned microchannels and exhibit good mechanical properties and high porosity.There are several ways to prepare porous polymeric structures, such as sintering, stretching, track etching and phase separation processes. In this work Phase separation method using anti-solvent of selected polymer in liquid nitrogen was used to fabricate the porous structures. Considering physical and chemical peroperties of polycyclic aromatic hydrocarbons, porous polystyrene make to be good sorbents. Solvent supported microextraction technique was applied to extract polycyclic...
Preparation and Characterization of Polymeric Nanocomposite Membrane used in Li-Ion Batteries, M.Sc. Thesis Sharif University of Technology ; Pircheraghi, Gholamreza
In Lithium ion batteries, the separator is membrane that placed between the cathode and the anode is one of critical components. Its primary function is to effectively transport ionic charge carriers between two electrodes as an efficient ionic conductor as well as to prevent the electric contact between them as a good electric insulator. The separator does not involve directly in any cell reactions, but its structure and properties play an important role in determining the battery performance. Commercially available polyolefin separators low cost, good electric resistance, high electrochemical stability, and effectively prevent thermal runaway caused by the electrical short-circuits or...
Numerical Investigation of Turbulent Flow Inside De-Oiling Hydrocyclones Using Large Eddy Simulation Approach, M.Sc. Thesis Sharif University of Technology ; Farhanieh, Bijan
Hydrocyclones are used for separating different materials from liquids in a variety of applications. Compactness, efficiency, reliability and low maintenance costs are their noteworthy characteristics. Dewatering and deoiling hydrocyclones used for refining crude oil or oily waste water in offshore platforms are examples of liquid-liquid hydrocyclones. Separation process in hydrocyclones is based on the fact that swirl flow induces a centrifugal force and leads to separation due to density difference. The density difference in liquid-liquid mixtures is smaller than solid-liquid types and trying to separate one liquid from another takes much more effort than the other type. Increase of...
Study on the Exfoliation of Graphite into Graphene by Electrochemical Method and Its Application in Thermoplastic Polyurethane Nanocomposite, M.Sc. Thesis Sharif University of Technology ; Pircheraghi, Gholamreza
Graphene is two dimensional nanomaterial, single layer of carbon atoms that exhibited excellent properties like high electrical conductivity and stiffness, but producing graphene and obtaining a good dispersion of graphene in a polymer matrix is still a major challenge. In this study by using the electrochemical route several graphene with different degree of oxidation produced in different electrolyte medium. According to XRD data, product of electrochemical exfoliation in dilute HNO3 medium includes 50% few-layer graphene (5 layers) and 25% GO and the rest are multi-layer graphene. Nonsolvent induced phase separation method were used to prepare TPU/Graphene nanocomposite. Different methods...
Simulating Dynamics of Immiscible Liquids Separation Using Microfluidics, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Aliasghar
Most of industrial and laboratory processes are faced with liquid-liquid emulsions particularly aqueous-organic ones in their different product streams which determine the need to perform phase separation due to enviromental problems or need to increase the product purity. In this project, due to presence of a water-hexane two phase flow mixture in the outflow of a microractor that performs Lithium-Bromine exchange reaction, a capillary microchip separator has been designed in order to separate water through capillary channel and hexane through main channel outlet using interfacial forces and wettability effects. To obtain a desired phase separation, the pressure drop through main channel...
Phase Separation in Binary Liquid Crystal Mixtures, M.Sc. Thesis Sharif University of Technology ; Ejtehadi, Mohammad Reza
Phase separation of a 50:50 binary system composed of two prolate ellipsoids with different axis ratios is investigated through molecular dynamics simulation. The system can be considered as a coarse-grained model of a binary liquid crystal mixture. Phase separation has been detected in the system by changing the density as the control parameter. The system goes through two different phase changes, one being the phase change due to phase separation and the other one due to orientational phase transition. In the latter case coexistence of the two particles results in simultaneous phase transition
Construction of Suitable Polymeric Membrane by Thermal Induce Phase Separation (TIPS) for using in the Membrane Bioreactor (MBR), M.Sc. Thesis Sharif University of Technology ; Farhadi, Fathollah ; Mousavi, Abbas
In this study, the response surface methodology (RSM) based on the central composite design (CCD) were used to prepare a polypropylene grafted maleic anhydride (PP-g-MA) microporous flat sheet membrane via thermally induced phase separation (TIPS) method. Mixture of dibutyl phthalate (DBP) and dioctyl phthalate (DOP) were used as diluent. The effect of the polymer composition and coagulation bath temperature on the morphology and performance of the fabricated microporous membranes in a bioreactor (MBR) were investigated. Analysis of variance (ANOVA) was used to determine which variables and interactions between variables have a significant effect on our responses. The ANOVA revealed that the...
Microwave-assisted extraction and high-throughput monolithic-polymer-based micro-solid-phase extraction of organophosphorus, triazole, and organochlorine residues in apple, Article Journal of Separation Science ; Volume 39, Issue 3 , 2016 , Pages 576-583 ; 16159306 (ISSN) ; Es Haghi, A ; Basiri Pour, F ; Sharif University of Technology
A high-throughput micro-solid-phase extraction device based on a 96-well plate was constructed and applied to the determination of pesticide residues in various apple samples. Butyl methacrylate and ethylene glycol dimethacrylate were copolymerized as a monolithic polymer and placed in the cylindrically shaped stainless-steel meshes of 96-micro-solid-phase extraction device and used as an extracting unit. Before the micro-solid-phase extraction, microwave-assisted extraction was employed to facilitate the transfer of the pesticide residues from the apple matrix to liquid media. Then, 1 mL of the aquatic samples was transferred into the 96-well plate and the 96-micro-solid-phase extraction...
Phase segregation susceptibility of ZA27 alloy at different shear rates, Article 9th International Conference on Semi-Solid Processing of Alloys and Composites, S2P 2006, Busan, 11 September 2006 through 13 September 2006 ; Volume 116-117 , 2006 , Pages 225-230 ; 10120394 (ISSN); 3908451264 (ISBN); 9783908451266 (ISBN) ; Aashuri, H ; Shalchi, B ; Sharif University of Technology
Trans Tech Publications Ltd 2006
Back extrusion technique was employed to characterize phase segregation tendency of mechanically stirred ZA27 alloy at different deformation rates. Variation of segregation intensity with ram diameter was found to follow opposite trends at low and high ram speeds. At sufficiently high ram speeds, small rams are of better performance in minimizing segregation whereas at low ram speeds, large rams result in less pronounced segregation. In addition, increasing ram speed invariably decreases segregation degree. Back extrusion at very high shear rates provided via a Drop Extruder Apparatus capable of displacing ram at speeds in excess of 1m/s results in production of very homogeneous products in...
Experimental and numerical investigation of low-temperature performance of modified asphalt binders and mixtures, Article Road Materials and Pavement Design ; 2016 , Pages 1-22 ; 14680629 (ISSN) ; Karimi, M. M ; Tabatabaee, N ; Sharif University of Technology
Taylor and Francis Ltd 2016
Thermal cracking is the prevalent type of distress experienced by asphalt pavements in cold regions. It is widely assumed that when thermal stresses induced in the pavement exceed the tensile strength of the asphalt surface layer, cracking occurs; however, the role of thermal fatigue should not be ignored. To better describe the low-temperature (LT) performance properties of modified asphalt binders, a new parameter, normalised tensile stress (NTS), was defined in this research. NTS values were compared with bending beam rheometer (BBR), direct tension (DT) and semi-circular bending (SCB) fracture test results. The m-value parameter of the BBR test specifies the type of asphalt binder. This...
Plant protein-based hydrophobic fine and ultrafine carrier particles in drug delivery systems, Article Critical Reviews in Biotechnology ; Volume 38, Issue 1 , 2018 , Pages 47-67 ; 07388551 (ISSN) ; Mirshekari, H ; Sahandi Zangabad, P ; Moosavi Basri, S. M ; Baniasadi, F ; Sharifi Aghdam, M ; Karimi, M ; Hamblin, M. R ; Sharif University of Technology
Taylor and Francis Ltd 2018
For thousands of years, plants and their products have been used as the mainstay of medicinal therapy. In recent years, besides attempts to isolate the active ingredients of medicinal plants, other new applications of plant products, such as their use to prepare drug delivery vehicles, have been discovered. Nanobiotechnology is a branch of pharmacology that can provide new approaches for drug delivery by the preparation of biocompatible carrier nanoparticles (NPs). In this article, we review recent studies with four important plant proteins that have been used as carriers for targeted delivery of drugs and genes. Zein is a water-insoluble protein from maize; Gliadin is a 70% alcohol-soluble...
Melt compounding of thermoplastic polyurethanes incorporating 1D and 2D carbon nanofillers, Article Polymer - Plastics Technology and Engineering ; Volume 56, Issue 7 , 2017 , Pages 732-743 ; 03602559 (ISSN) ; Pedrazzoli, D ; Pircheraghi, G ; Manas Zloczower, I ; Sharif University of Technology
Taylor and Francis Inc 2017
Thermoplastic polyurethane nanocomposites incorporating carbon nanotubes and graphene nanoplatelets were prepared through melt blending and compression molding, and the compounding process was optimized taking into account the different physical properties of one-dimensional carbon nanotubes and two-dimensional graphene nanoplatelets. Filler dispersion was further improved in the case of carbon nanotubes by noncovalent surface modification using a specific surfactant. The well-dispersed nanofillers favored enhanced phase separation in the thermoplastic polyurethane, leading to a better microstructure, which is able to improve the load transfer and maximize the tensile and viscoelastic...
PVDF/PU blend membrane separator for lithium-ion batteries via non-solvent-induced phase separation (NIPS), Article Journal of Solid State Electrochemistry ; Volume 25, Issue 8-9 , 2021 , Pages 2385-2394 ; 14328488 (ISSN) ; Fathollahi Zonouz, A ; Soltanieh, M ; Mousavi, S. A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH 2021
Membrane separator based on the polyvinylidene fluoride (PVDF) is prepared via the non-solvent-induced phase separation (NIPS) method with water and ethanol as non-solvent and a mixture of dimethylformamide (DMF) and acetone as solvent. The effect of various acetone/DMF ratios and non-solvent material on the physical and electrochemical properties of the separator is studied by FE-SEM, tensile strength, electrochemical AC-impedance spectroscopy (EIS), thermal stability, and linear sweep voltammetry (LSV). The charge-discharge studies are carried out by fabricating a lithium foil/polymer electrolyte membrane/LiFePO4 cell. The results show that with the change of solvent and non-solvent, the...
Property Investigation of Poly (Ethylene Co-vinyl Acetate)/Poly (l-Lactic Acid)/Organo Clay Nanocomposites, Article Journal of Polymers and the Environment ; Volume 27, Issue 12 , 2019 , Pages 2886-2894 ; 15662543 (ISSN) ; Ramazani SaadatAbadi, A ; Sharif University of Technology
Springer New York LLC 2019
In this study, EVAc/PLA/organo clay nanocomposites were prepared via solution mixing method. The SEM images were used to investigate the morphology of nanocomposites revealing no phase separation or agglomeration of disperse phase in EVAc/PLA blends and nanocomposites. SAXS spectra confirmed the intercalated morphology of nanocomposites. Soil burial test were carried out and the rate of degradation of the samples were measured indirectly. Oxygen gas permeability of EVAc was slightly decreased by adding PLA to the matrix, when small loads of clay caused dramatic improvement in barrier properties. Melt rheological frequency sweep test illustrated the compatibility of EVAc with low contents of...
Pectic acid–graphene oxide nanocomposite as an adsorbent in vortex-assisted dispersive solid-phase extraction for preconcentration of copper ion followed by flame atomic absorption spectrometry, Article Polymer Bulletin ; Volume 77, Issue 6 , 2020 , Pages 2821-2836 ; Shakerian, M ; Majeed, H. J ; Eftekhari, M ; Rezazadeh, N ; Sharif University of Technology
An efficient, green, novel and rapid vortex-assisted dispersive solid-phase extraction (VADSPE) technique was used for the preconcentration and determination of trace levels of Cu2+ followed by flame atomic absorption spectrometry. Graphene oxide (GO) was synthesized from graphite and then modified by pectic acid (poly-d-galacturonic acid, PA) to synthesize the pectic acid–graphene oxide (PA-GO) nanocomposite. The Fourier transform infrared spectrophotometry, field emission scanning electron microcopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis were used to characterize the synthesized GO-PA nanocomposite. By using VADSPE technique, PA-GO was used as an adsorbent for...
Experimental study and thermodynamic modeling for purification of extracted algal lipids using an organic/aqueous two-phase system, Article RSC Advances ; Volume 5, Issue 2 , 2015 , Pages 1153-1160 ; 20462069 (ISSN) ; Pazuki, G ; Vossoughi, M ; Sharif University of Technology
Royal Society of Chemistry 2015
The extraction and purification of lipids from the microalgae Chlorella vulgaris have been investigated. First, a mixture of hexane and ethanol was used to extract lipids from the algal biomass. Ultrasonication was employed to disrupt the cell wall and increase the extraction performance. Under these conditions, over 90% of the fatty acids in the biomass were extracted. Second, a biphasic system was formed by adding water and hexane to the extracted crude oil. In this way, fatty acids were mainly distributed in the organic phase (mostly hexane and ethanol) while most of the contaminants remained in the aqueous phase (mostly water and ethanol). Equilibrium distribution data between the phases...
A combined micro-solid phase-single drop microextraction approach for trace enrichment of volatile organic compounds, Article Analytical Methods ; Volume 7, Issue 16 , Jun , 2015 , Pages 6514-6519 ; 17599660 (ISSN) ; Zare, M ; Piri Moghadam, H ; Es haghi, A ; Sharif University of Technology
Royal Society of Chemistry 2015
An attempt was made to combine μ-solid phase extraction and headspace single drop microextraction techniques and use their advantages for trace determination of some volatile organic compounds in aqueous samples. After performing the two-step preconcentration approach, the desired analytes were determined by gas chromatography-mass spectrometry. A resorcinol-formaldehyde-based xerogel was used as the extraction medium in the μ-solid phase extraction (μ-SPE) method. Then, the extracted BTEX was eluted with a rather large amount of methanol. To remove the laborious process including solvent evaporation and further reconstitution, which is usually accompanied by loss of analytes and accuracy,...
Multi-response optimization followed by multivariate calibration for simultaneous determination of carcinogenic polycyclic aromatic hydrocarbons in environmental samples using gold nanoparticles, Article RSC Advances ; Volume 6, Issue 106 , 2016 , Pages 104254-104264 ; 20462069 (ISSN) ; Parastar, H ; Hormozi Nezhad, M. R ; Sharif University of Technology
Royal Society of Chemistry
In this study, a multivariate-based strategy was developed for simultaneous determination of thirteen carcinogenic polycyclic aromatic hydrocarbons (PAHs) in water samples using gold nanoparticles (AuNPs) as solid-phase extraction (SPE) sorbent combined with gas chromatography (GC). The extraction technique is based on the strong affinity between citrate-capped AuNPs and PAHs. Furthermore, characterization of AuNPs was performed by UV-vis spectroscopy and transmission electron microscopy (TEM) techniques. A rotatable central composite design (CCD) combined with multiple linear regression (MLR) was used for designing the extraction procedure and developing models using the GC peak areas of 13...
Biodegradable polyurethane acrylate/HEMA-grafted nanodiamond composites with bone regenerative potential applications: Structure, mechanical properties and biocompatibility, Article RSC Advances ; Volume 6, Issue 11 , 2016 , Pages 8743-8755 ; 20462069 (ISSN) ; Shojaei, A ; Abdekhodaie, M. J ; Sharif University of Technology
Royal Society of Chemistry
The present study demonstrates HEMA-grafted nanodiamond (ND-HEMA)/acrylate-terminated polyurethane-acrylate diluents (APUA) composites as promising materials for bone implant applications. Neat APUA and APUA composites containing ND-HEMA at different loadings up to 2 wt% were prepared by an in situ polymerization method. Morphological analysis demonstrated that ND-HEMAs were actually in the form of tightly bound aggregates which led to formation of big agglomerates at a concentration of 2 wt%. It was also suggested that ND-HEMAs were preferentially localized in the continuous soft domain of APUA; however it interacted by both soft and hard domains. Moreover, ND-HEMAs caused considerable...
Encapsulation of food components and bioactive ingredients and targeted release, Article International Journal of Engineering, Transactions A: Basics ; Volume 33, Issue 1 , 2020 , Pages 1-11 ; Hajiabbas, M ; Pakzad, H ; Sajadi Dehkordi, S ; Vossoughi, A ; Sharif University of Technology
Materials and Energy Research Center 2020
The potential utilization of encapsulation techniques in food, pharmaceutical and agricultural products preparation, presents a new alternative for complementary technologies such as targeting delivery vehicles and carriers for active food ingredients. Encapsulation could be accomplished by different techniques like: simple or complex coacervation, emulsification technique, phase separation, spray drying, spray chilling or spray cooling, extrusion coating, freeze drying, fluidized-bed coating, liposomal entrapment, centrifugal suspension separation, co-crystallization and molecular inclusion complexation. Encapsulation is a method by which one bioactive material or mixture of materials is...