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    Simultaneous separation of H2S and CO2 from CH4 by a high silica CHA-type zeolite membrane

    , Article Journal of Membrane Science ; Vol. 470, issue , 2014 , pp. 159-165 ; ISSN: 03767388 Maghsoudi, H ; Soltanieh, M ; Sharif University of Technology
    A high silica CHA-type membrane was synthesized by the in-situ crystallization method on a disk like α-alumina porous support to separate both acid (H2S, CO2) gases from methane. The membrane showed a permeance of 3.39×10-8mol/m2sPa for pure CO2with CO2/CH4 ideal selectivity of 21.6 at 303K and 100kPa pressure difference across the membrane. The membrane was also tested with N2 and O2 pure gases indicating a small O2/N2 selectivity of 1.2-1.4, which shows that this type of membrane is not suitable for O2/N2 separation. The membrane performance was also analyzed by binary (CO2-CH4) and ternary (H2S-CO2-CH4) gas mixtures, with compositions near the real sour natural gas (CO2: 2.13mol%, H2S:... 

    Structural analysis of Y3Ba5Cu8O 19-δ high-Tc superconductor by ab initio density functional theory

    , Article Physica C: Superconductivity and its Applications ; Volume 497 , 15 February , 2014 , 2014, Pages 84-88 ; ISSN: 09214534 Khosroabadi, H ; Rasti, M ; Akhavan, M ; Sharif University of Technology
    The details of the crystal structure of the recently discovered Y 3Ba5Cu8O18+δ (Y358) superconductor have been determined by ab initio density functional theory. Total energy calculation has been performed for three different suggested structures with different oxygen content. The structure with a center of inversion symmetry and the highest oxygen concentration has the lowest total energy. Thus, it is the best choice for the Y358 crystal structure. By investigating the detailed structure, it is seen that this compound is arranged either of YBa2Cu3O7 and YBaCu2O 5 or YBaCu2O5 and BaCuO2 substructural blocks in the c direction. The difference between the total energy of Y358 compound and the... 

    Electrospun titania sol-gel-based ceramic composite nanofibers for online micro- solid-phase extraction with high-performance liquid chromatography

    , Article Journal of Separation Science ; Vol. 37, issue. 15 , August , 2014 , pp. 1982-1988 ; ISSN: 16159306 Bagher, H ; Piri-Moghadam, H ; Rastegar, S ; Taheri, N ; Sharif University of Technology
    Titanium(IV) tetraisopropoxide was employed as a metal oxide sol-gel precursor to prepare ceramic composite nanofibers by the electrospinning system. To facilitate this process and obtain the desired nanofibers with higher aspect ratios and surface area, poly(vinylpyrrolidone) was added to the sol of titania. Four ceramic nanofibers sheets based on titania were prepared while each sheet contained different transition metals such as Fe-Mn, Fe-Ni, Fe-Co, and Fe-Mn-Co-Ni. The scanning electron microscope images showed good homogeneity for all the prepared ceramic composites with a diameter range of 100-250 nm. The sorption efficiency was investigated by a micro-solid-phase extraction setup in... 

    Preparation and characterization of SAPO-34 nanoparticles-mixed matrix membranes (MMM) via combined phase separation method for CO2/CH4 gas separation application

    , Article Technical Proceedings of the NSTI Nanotechnology Conference and Expo, NSTI-Nanotech ; Vol. 1 , 2014 , pp. 253-256 ; ISBN: 9781482258264 Jahanbakhsh Asl, H ; Soltanieh, M ; Azadi, R ; Sharif University of Technology
    Phase separation is one of the common methods for fabrication of polymeric membrane, which classifies into the categories of Thermally Induced Phase Separation (TIPS) and Nonsolvent Induced Phase Separation (NIPS), i.e. heat and mass transfer induced phase separation, respectively. NIPS has been applied more commonly than TIPS, but the membranes which have resulted from this technique have macro finger-like voids, weak mechanical strength and not high separation ability in comparison with the TIPS. In contrast, membranes produced by the TIPS method have micro scale pores, high mechanical strength and also high separation capability, however, polymeric solutions prepared at high temperatures... 

    A novel magnetic poly(aniline-naphthylamine)-based nanocomposite for micro solid phase extraction of rhodamine B

    , Article Analytica Chimica Acta ; Volume 794 , 2013 , Pages 38-46 ; 00032670 (ISSN) Bagheri, H ; Daliri, R ; Roostaie, A ; Sharif University of Technology
    A novel Fe3O4-poly(aniline-naphthylamine)-based nanocomposite was synthesized by chemical oxidative polymerization process as a magnetic sorbent for micro solid phase extraction. The scanning electron microscopy images of the synthesized nanocomposite revealed that the copolymer posses a porous structure with diameters less than 50nm. The extraction efficiency of this sorbent was examined by isolation of rhodamine B, a mutagenic and carcinogenic dye, from aquatic media in dispersion mode. Among different synthesized polymers, Fe3O4/poly(aniline-naphthylamine) nanocomposite showed a prominent efficiency. Parameters including the desorption solvent, amount of sorbent, desorption time, sample... 

    High-throughput micro-solid phase extraction on 96-well plate using dodecyl methacrylate-ethylen glycol dimethacrylate monolithic copolymer

    , Article Analytica Chimica Acta ; Volume 792 , August , 2013 , Pages 59-65 ; 00032670 (ISSN) Bagheri, H ; Es'haghi, A ; Es-haghi, A ; Mohammadkhani, E ; Sharif University of Technology
    A novel high-throughput device based on 96-micro-solid phase extraction (96-μ-SPE) system was constructed for multiresidue determination of nine pesticides in aquatic samples. The extraction procedure was performed on a commercially available 96-well plate system. The extraction module consisted of 96 pieces of 1cm×3cm of cylindrically shaped stainless steel meshes. The prepared meshes were fixed in a home-made polytetrafluoroethylene-based constructed ninety-six holes block for possible simultaneous immersion of meshes into the center of individual wells. Dodecyl methacrylate and ethylene glycol dimethacrylate was copolymerized as a monolithic polymer and placed in the cylindrically shaped... 

    Multivariate curve resolution-particle swarm optimization: A high-throughput approach to exploit pure information from multi-component hyphenated chromatographic signals

    , Article Analytica Chimica Acta ; Volume 772 , 2013 , Pages 16-25 ; 00032670 (ISSN) Parastar, H ; Ebrahimi Najafabadi, H ; Jalali Heravi, M ; Sharif University of Technology
    Multivariate curve resolution-particle swarm optimization (MCR-PSO) algorithm is proposed to exploit pure chromatographic and spectroscopic information from multi-component hyphenated chromatographic signals. This new MCR method is based on rotation of mathematically unique PCA solutions into the chemically meaningful MCR solutions. To obtain a proper rotation matrix, an objective function based on non-fulfillment of constraints is defined and is optimized using particle swarm optimization (PSO) algorithm. Initial values of rotation matrix are calculated using local rank analysis and heuristic evolving latent projection (HELP) method. The ability of MCR-PSO in resolving the chromatographic... 

    Photoactive and self-cleaning TiO 2-SiO 2 thin films on 316L stainless steel

    , Article Thin Solid Films ; Volume 520, Issue 20 , 2012 , Pages 6355-6360 ; 00406090 (ISSN) Boroujeny, B. S ; Afshar, A ; Dolati, A ; Sharif University of Technology
    In this study, TiO 2-SiO 2 nanocomposite films with different amounts of SiO 2 were prepared by sol-gel process and were coated onto stainless steel 316L. The effect of addition of various amount of SiO 2 in the precursor solution on the photocatalysis, photo-generated hydrophilicity and self-cleaning property of TiO 2 thin films was investigated by X-ray diffraction, Fourier transform infrared spectroscopy, water contact angle measurements and UV spectroscopy. In the tested ranges of SiO 2 content and sintering temperature, the highest photocatalytic activity and self-cleaning property were observed in the 15 mol% SiO 2 sample sintered at 750 °C. Addition of less than 30 mol% SiO 2 had a... 

    Effects of nucleation agents on the preparation of transparent glass-ceramics

    , Article Journal of the European Ceramic Society ; Volume 32, Issue 11 , August , 2012 , Pages 2989-2994 ; 09552219 (ISSN) Ghasemzadeh, M ; Nemati, A ; Baghshahi, S ; Sharif University of Technology
    Elsevier  2012
    Formation of transparent glass-ceramic in the system MgO-SiO 2-Al 2O 3-K 2O-B 2O 3-F with and without addition of LiF and NaF has been investigated. Crystallization of glass-sample was conducted by controlled thermal heat-treatment, at determined nucleation and crystallization temperatures. In this regard, the effects of addition of LiF and NaF were investigated on the crystallization behavior and transparency of the samples. Low transmission (less than 80% at 600. nm) was observed in the basic composition (K).The addition of NaF and LiF caused more intense phase separation in the system. The results indicated that the glass-ceramic can remain transparent if fine grains with nano size are... 

    Simulation of two-phase liquid-vapor flows using a high-order compact finite-difference lattice Boltzmann method

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 92, Issue 5 , November , 2015 ; 15393755 (ISSN) Hejranfar, K ; Ezzatneshan, E ; Sharif University of Technology
    American Physical Society  2015
    A high-order compact finite-difference lattice Boltzmann method (CFDLBM) is extended and applied to accurately simulate two-phase liquid-vapor flows with high density ratios. Herein, the He-Shan-Doolen-type lattice Boltzmann multiphase model is used and the spatial derivatives in the resulting equations are discretized by using the fourth-order compact finite-difference scheme and the temporal term is discretized with the fourth-order Runge-Kutta scheme to provide an accurate and efficient two-phase flow solver. A high-order spectral-type low-pass compact nonlinear filter is used to regularize the numerical solution and remove spurious waves generated by flow nonlinearities in smooth regions... 

    Sol-gel-based silver nanoparticles-doped silica - Polydiphenylamine nanocomposite for micro-solid-phase extraction

    , Article Analytica Chimica Acta ; Volume 886 , July , 2015 , Pages 56-65 ; 00032670 (ISSN) Bagheri, H ; Banihashemi, S ; Sharif University of Technology
    Elsevier  2015
    A nanocomposite of silica-polydiphenylamine doped with silver nanoparticles (Ag-SiO2-PDPA) was successfully synthesized by the sol-gel process. For its preparation, PDPA was mixed with butanethiol capped Ag nanoparticles (NPs) and added to the silica sol solution. The Ag NPs were stabilized as a result of their adsorption on the SiO2 spheres. The surface characteristic of nanocomposite was investigated using scanning electron microscopy (SEM). In this work the Ag-SiO2-PDPA nanocomposite was employed as an efficient sorbent for micro-solid-phase extraction (μ-SPE) of some selected pesticides. An amount of 15 mg of the prepared sorbent was used to extract and... 

    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) Abedini Najafabadi, H ; 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) Bagheri, H ; 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,... 

    Resorcinol-formaldehyde xerogel as a micro-solid-phase extraction sorbent for the determination of herbicides in aquatic environmental samples

    , Article Journal of Separation Science ; Volume 38, Issue 13 , 2015 , Pages 2305-2311 ; 16159306 (ISSN) Es Haghi, A ; Zare, M ; Piri Moghadam, H ; Bagheri, H ; Sharif University of Technology
    In this study, organic aerogels were synthesized by the sol-gel polycondensation of mixed cresol with formaldehyde in a slightly basic aqueous solution. Carbon aerogels and xerogels are generated by pyrolysis of organic aerogels. The novel sol-gel-based micro-solid-phase extraction sorbent, resorcinol-formaldehyde xerogel, was employed for preconcentration of some selected herbicides. Three herbicides of the aryloxyphenoxypropionate group, clodinafop-propargyl, haloxyfop-etotyl, and fenoxaprop-P-ethyl, were extracted from aqueous samples by micro-solid-phase extraction and subsequently determined by gas chromatography with mass spectrometry. The effect of different parameters influencing the... 

    Synthesis and analysis of the properties of ferro-fluids

    , Article ICONN 2010 - Proceedings of the 2010 International Conference on Nanoscience and Nanotechnology, 22 February 2010 through 26 February 2010, Sydney, NSW ; 2010 , Pages 91-93 ; 9781424452620 (ISBN) Maleki Jirsaraei, N ; Ghane Motlagh, B ; Ghane Golmohamadi, F ; Ghane Motlagh, R ; Rouhani, S ; Sharif University of Technology
    We report the rheological properties of ferro-fluid (FF) containing iron oxide nano-particles. At first, a FF was synthesized by using chemical co-precipitaton[1]. The microstructure study using SEM revealed that the FF contained nano-particles with the mean particle size of 35nm. The XRD study revealed that we have well crystallized structures of magnetite; they appeared to be approximately single crystalline structures. The rheological results proved that the FF has non Newtonian behavior, it is a shear thinning fluid in all magnetic fields, Moreover, the magnetic field increases the viscosity in a definite shear rate due to the nano-particles agglomerations and formation of chain-like... 

    Extraordinary swelling behavior of poly (AMPS) organogelin solvent/DMSO binary mixed media

    , Article Journal of Applied Polymer Science ; Volume 117, Issue 2 , July , 2010 , Pages 1127-1136 ; 00218995 (ISSN) Zohuriaan Mehr, M. J ; Kabiri, K ; Kheirabadi, M ; Sharif University of Technology
    The present article deals with super-swelling behavior of crosslinked homopolymer of 2-acrylamido-2-methylpropane sulfonic acid, poly(AMPS), in binary mixtures of dimethyl sulfoxide (DMSO) and various polar solvents including water, mono-, and polyhydric alcohols, and amide solvents such as N-methyl pyrrolidone. Extraordinary phase transition sequences including a new unusual swelling phenomenon, referred to as "overentrant" swelling, was observed for this polymeric organogel in the solvent/DMSO mixtures. The swelling behaviors were preliminarily explained based on the major interactions involved in the solvation process and dielectric constant of the swelling media. It was established that... 

    Investigation of the interphase effects on the mechanical behavior of carbon nanotube polymer composites by multiscale modeling

    , Article Journal of Applied Polymer Science ; Volume 117, Issue 1 , March , 2010 , Pages 361-367 ; 00218995 (ISSN) Montazeri, A ; Naghdabadi, R ; Sharif University of Technology
    In this article, a multiscale modeling procedure is implemented to study the effect of interphase on the Young's modulus of CNT/polymer composites. For this purpose, a three-phase RVE is introduced which consists of three components, i.e., a carbon nanotube, an interphase layer, and an outer polymer matrix. The nanotube is modeled at the atomistic scale using molecular structural mechanics. Moreover, three-dimensional elements are employed to model the interphase layer and polymer matrix. The nanotube and polymer matrix are assumed to be bonded by van der Waals interactions based on the Lennard-Jones potential at the interface. Using this Molecular Structural Mechanics/Finite Element... 

    A flow injection μ-solid phase extraction system based on electrospun polyaniline nanocomposite

    , Article Journal of Chromatography A ; Volume 1433 , February , 2016 , Pages 34–40 ; 00219673 (ISSN) Bagheri, H ; Khanipour, P ; Roostaie, A ; Sharif University of Technology
    In this study, a fast and sensitive flow injection μ-solid phase extraction (FI-μ-SPE) technique based on an electrospun polyaniline (PANI) nanocomposite in conjunction with gas chromatography-mass spectrometry (GC-MS) was developed. The PANI-based nanocomposite was synthesized by electrospinning of a solution containing polyvinyl alcohol (PVA)/PANI. The majority of PVA template was subsequently removed from the whole PVA/PANI nanofibers blend by exposing the electrospun nanocomposite to hot water. The homogeneity, porosity and characterization of the electrospun nanofibers were investigated by the scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. Due to... 

    Core-shell electrospun polybutylene terephthalate/polypyrrole hollow nanofibers for micro-solid phase extraction

    , Article Journal of Chromatography A ; Volume 1434 , 2016 , Pages 19-28 ; 00219673 (ISSN) Bagheri, H ; Rezvani, O ; Banihashemi, S ; Sharif University of Technology
    Elsevier B.V  2016
    In the present work, a new micro-solid phase extraction (μ-SPE) sorbent as an extracting medium based on core-shell nanofibers was synthesized by electrospinning. The core-shell nanofibers of polyvinylpyrrolidone-Polybutylene terephthalate/polypyrrole (PVP-PBT/PPy) were electrospun and subsequently, modified hollow nanofibers were prepared by removing the central PVP moiety. Moreover, conventional PBT/PPy was also prepared for the comparison purposes. The homogeneity and the porous surface structure of the core-shell nanofibers were confirmed by scanning electron microscopy (SEM). The applicability of the fabricated nanofibers-coating was examined by immersed μ-SPE of some selected triazine... 

    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) Bagheri, H ; Es Haghi, A ; Basiri Pour, F ; Sharif University of Technology
    Wiley-VCH Verlag 
    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...