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Modified CMC: Part1-optimized synthesis of carboxymethyl cellulose-g-polyacrylonitrile
, Article Iranian Polymer Journal (English Edition) ; Volume 14, Issue 2 , 2005 , Pages 131-138 ; 10261265 (ISSN) ; Pourjavadi, A ; Sadeghi, M ; Sharif University of Technology
2005
Abstract
As the first part of a continued research on conversion of carboxymethyl cellulose-sodium salt (CMC) to useful biopolymer-based materials, large numbers of cyanide functional groups were introduced onto CMC by grafting with polyacrylonitrile (PAN). The graft copolymerization reactions were carried out under nitrogen atmosphere using ceric ammonium nitrate (CAN) as an initiator. Evidence of grafting was obtained by comparing FTIR spectra of CMC and the graft copolymer as well as solubility characteristics of the products. The synthetic conditions were systematically optimized through studying the effective factors including temperature and concentrations of initiator, acrylonitrile monomer,...
Dendrimers and Other Nanostructures by the Approach of Graph Theory
, M.Sc. Thesis Sharif University of Technology ; Mahmoodian, Ebadollah (Supervisor)
Abstract
In this thesis, we study the application of graph theory in chemistry. Such as, molecular graphs, modeling, algorithms, topologicalindicesandsoon. Themaingoalinthisresearchis collecting problems in chemistry which have mathematical models, specially in graph theory. Also we study the methods applied to them by considering the problems in chemistry with mathematical approach. In particular case, dendrimers and other structures of chemistry have been attributed to some graphs, where by studying their graphical parameters, like connectivity, independent sets, perfect matchings, isomorphism and topological indices and other parameters, we obtain some results in chemistry
A Survey on Electronic Structure of the Chlorophyll Molecules Participating in Photosynthesis Process
, M.Sc. Thesis Sharif University of Technology ; Vesaghi, Mohammad Ali (Supervisor)
Abstract
Optimized structure of the chlorophyll a and b molecules was obtained for LDA and GGA approximation by SIESTA package. Calculation illustrate that tails are curved in the optimized structure for both chlorophyll a and chlorophyll b molecules; in addition, Antennas, which are attached to the head of molecules, are located in optimized-spatial state. This optimized structure of chlorophyll a is similar to the calculated structure in ref [42]. Electrical dipole are calculated from ground state electron density of chlorophylls. Total electrical dipole of chlorophyll a for GGA and LDA approximation are 4.662 and 4.813 Debay, and these value for chlorophyll b are 1.435 and 1.302 Debay,...
Synthesis and Characterization of Grapheme Foams Fabricated by Chemical Vaporization Deposition
, M.Sc. Thesis Sharif University of Technology ; Akhavan, Omid (Supervisor) ; Azimirad, Rouhollah (Co-Advisor)
Abstract
The main purpose of this theses is to synthesize graphene by chemical vapor deposition (CVD) of a hydrocarbon gas such as methane on the nickel foam substrate and then to characterize this kind of graphene. Graphene is a single layer of carbon atoms, discovered in 2004, which has led mankind to new eras in all fields by its extraordinary features such as extra high electron mobility, high thermal conductivity, excellent mechanical strength, optical transparence and extra high specific surface. The advantage of this method compared to other methods is that the graphene generated has a better structural quality. Graphene foam firstly, because of the continuity of the foam structure, has better...
Storage of Information in Chemical Compounds
, M.Sc. Thesis Sharif University of Technology ; Shafiee, Afshin (Supervisor)
Abstract
Regarding the notable progress in communication and competition theories as well as natural sciences, the study of the concepts of information has displayed more attention in recent years.Information, entropy and energy are interrelated concepts. In one hand one can infer that entropy is a quantitation measure of information and on the other hand systems which carry information can accumulated energy.Here, we are going to survey the qualitation as well as quantitation aspects of information with concentration on the behavior of chemical agents as information processors
The study of growth and coagulation of titania nanoparticles by chemical vapor synthesis
, Article Journal of Nuclear Science and Technology ; No.53 , 2010 , pp. 20-29 ; Saberyan, K ; Shahri, F ; Simchi, A. (Abdolreza) ; Sharif Univesity of Technology
Abstract
Chemical Vapor Synthesis route was used for synthesis of titanium dioxide (TiO2) nanoparticles in hot-walled reactor at 800degreeC using TiCl4 as precursor. The effect of processing parameters e.g., temperature and amount of precursor on phase structure, size, purity, coagulation and agglomeration of nanoparticles were investigated in this respect. Also, the H2O effects on the size, crystallinity, phase transformation and purity of nanoparticles were studied. Comprehensive experimental observations were confirmed by transmission electron microscopy, X-ray diffraction analysis and thermal gravimetric-differential thermal analysis results. The obtained results showed that by increasing the...
Studying the Mechanistic Behavior of Heavy Oil Displacement Using a Group of Alkalis and Surfactant Mixtures
, Article Chemical Engineering Communications ; Vol. 202, issue. 3 , May , 2015 , p. 366-374 ; ISSN: 00986445 ; Jadaly, A ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
Abstract
In this study, a mixture-based sulfonate-based surfactant with a novel formula capable of functioning in real oil reservoir conditions was prepared and some microscopic parameters, like its compatibility state, emulsion behavior, interfacial tension, and temperature dependency in the presence of a heavy oil sample, and two of the most popular alkalis were analyzed; then the results were compared with those of a commercial sulfate-based surfactant. The designed surfactant provided an optimum three-phase region in relatively high salinity media; however, its optimum value decreased when adding any alkaline materials; this trend was reversed for the solutions made with the sulfate-based...
Predictions of toughness and hardness by using chemical composition and tensile properties in microalloyed line pipe steels
, Article Neural Computing and Applications ; 2014 ; Khalaj, G ; Pouraliakbar, H ; Jandaghi, M. R ; Sharif University of Technology
Abstract
Artificial neural networks with multilayer feed forward topology and back propagation algorithm containing two hidden layers are implemented to predict the effect of chemical composition and tensile properties on the both impact toughness and hardness of microalloyed API X70 line pipe steels. The chemical compositions in the forms of "carbon equivalent based on the International Institute of Welding equation (CEIIW)", "carbon equivalent based on the Ito-Bessyo equation (CEPcm)", "the sum of niobium, vanadium and titanium concentrations (VTiNb)", "the sum of niobium and vanadium concentrations (NbV)" and "the sum of chromium, molybdenum, nickel and copper concentrations (CrMoNiCu)", as well...
Interaction of 3D dewetting nanodroplets on homogeneous and chemically heterogeneous substrates
, Article Journal of Physics Condensed Matter ; Vol. 26, Issue. 22 , 2014 ; ISSN: 09538984 ; Moosavi, A ; Sharif University of Technology
Abstract
Long-time interaction of dewetting nanodroplets is investigated using a long-wave approximation method. Although three-dimensional (3D) droplets evolution dynamics exhibits qualitative behavior analogous to two-dimensional (2D) dynamics, there is an extensive quantitative difference between them. 3D dynamics is substantially faster than 2D dynamics. This can be related to the larger curvature and, as a consequence, the larger Laplace pressure difference between the droplets in 3D systems. The influence of various chemical heterogeneities on the behavior of droplets has also been studied. In the case of gradient surfaces, it is shown how the gradient direction could change the dynamics. For a...
Application of ideal temperature gradient technology to optimize the chemical exchange and distillation process of boron isotopes separation by (CH3)2O-BF3 complex
, Article Chemical Engineering and Processing: Process Intensification ; Volume 76 , February , 2014 , Pages 26-32 ; ISSN: 02552701 ; Ahmadi, S. J ; Sharif University of Technology
Abstract
To exert the optimum effect, the chemical exchange process to boron isotope separation was investigated. In this enrichment method the distillation of dimethyl ether-boron trifluoride complex, which was one of the most efficient industrial methods for purification of isotope boron-10, was optimized. In chemical exchange process of boron isotopes separation two chemical reactions occur. The first one is the decomposition reaction that is an endothermic reaction. The second one is the exchange reaction that is a pyrogenic reaction. With increasing temperature, the decomposition reaction is speeded while the exchange reaction is slowed down. Affecting on both decomposition and exchange...
Probing theoretical level effect on fluorine chemical shielding calculations
, Article Concepts in Magnetic Resonance Part A: Bridging Education and Research ; Volume 42, Issue 4 , 2013 , Pages 140-153 ; 15466086 (ISSN) ; Tafazzoli, M ; Sharif University of Technology
2013
Abstract
The extensive quantum-chemical calculations are assessed for prediction of the 19F nuclear magnetic shielding constants. The methods within domain of density functional theory (DFT) and ab initio, Hartree-Fock (HF), and second-order Møller-Plesset perturbation theory (MP2) are employed for calculation of the 19F chemical shielding constants for a series of 30 small fluorine-containing molecules. The importance of inclusion of four factors, namely, electron correlation treatment, triple-ξ valence shell, diffuse function, and polarization function on calculating the fluorine NMR chemical shieldings for a variety of Pople's standard basis sets at gauge invariant atomic orbital (GIAO) and...
Michael addition reaction of anthrone to nitroolefins in water
, Article Synthetic Communications ; Volume 43, Issue 5 , May , 2013 , Pages 744-748 ; 00397911 (ISSN) ; Karimi, N ; Saidi, M. R ; Sharif University of Technology
2013
Abstract
Michael addition reaction of anthrone to nitroolefins is described in water without using any catalyst to prepare 9-(2-nitro-1-arylethyl)anthracene-10(9H)- ones. This method is green and efficient and gives good yields of products. The solvent effect is also investigated
An approach to evaluation of 19F-NMR chemical shifts via basis functions analysis in fluorinated small compounds
, Article Concepts in Magnetic Resonance Part A: Bridging Education and Research ; Volume 40 A, Issue 4 , 2012 , Pages 192-204 ; 15466086 (ISSN) ; Tafazzoli, M ; Sharif University of Technology
Wiley
2012
Abstract
An extensive GIAO (gauge-including atomic orbital) calculation has been made within Hartree-Fock (HF), density functional theory (DFT) and second-order Møller-Plesset perturbation theory (MP2), in conjunction with selected basis sets for the prediction of 19F chemical shift values of 26 different F nuclei in small fluorine-containing molecules. The effect of four factors, namely, electron correlation treatment, triple-ξ valence shell, diffuse function and polarization function were assessed using a systematic comparison of the results. Based on types of series, the optimized wave functions were proposed for different molecules. An additional comparison of the principal components of the...
Nano-layered manganese oxides as low-cost, easily synthesized, environmentally friendly and efficient catalysts for epoxidation of olefins
, Article RSC Advances ; Volume 2, Issue 9 , 2012 , Pages 3654-3657 ; 20462069 (ISSN) ; Najafpour, M. M ; Nayeri, S ; Pashaei, B ; Bagherzadeh, M ; Sharif University of Technology
2012
Abstract
Incorporation of calcium(ii), zinc(ii) and aluminium(iii) to manganese oxides greatly improved the activity of manganese oxide towards the epoxidation of olefins in the presence of anhydrous tert-butyl hydroperoxide as an oxidant
Boric acid/glycerol as an efficient catalyst for regioselective epoxide ring opening by aromatic amines in water
, Article Green Chemistry Letters and Reviews ; Volume 5, Issue 1 , 2012 , Pages 1-5 ; 17518253 (ISSN) ; Gholami, H ; Saidi, M. R ; Sharif University of Technology
Abstract
Regioselective epoxides ring opening with aromatic amines using boric acid and glycerol in water as a green media have been investigated. Corresponding β-amino alcohols were obtained with excellent yields and considerable regioselectivity. High yields of the products and mild reaction conditions using green catalyst and water as a green solvent are some advantages of this procedure
Domino effect in process-industry accidents - An inventory of past events and identification of some patterns
, Article Journal of Loss Prevention in the Process Industries ; Volume 24, Issue 5 , 2011 , Pages 575-593 ; 09504230 (ISSN) ; Abbasi, T ; Rashtchian, D ; Abbasi, S. A ; Sharif University of Technology
Abstract
The paper presents an inventory, perhaps the most comprehensive till date, of the major process-industry accidents involving 'domino effect'. The inventory includes, among other relevant information, the sequence of accidents that had occurred in each domino episode. The information has been analyzed to identify several patterns which may be useful in further work on understanding domino effect and reducing the probability of its occurrence in future. A concept of 'local domino effect' has been introduced
Synthesis of titanium nano-particles via chemical vapor condensation processing
, Article Journal of Alloys and Compounds ; Volume 509, Issue 19 , 2011 , Pages 5825-5828 ; 09258388 (ISSN) ; Halali, M ; Sobhani, M ; Ghandehari, R. T ; Sharif University of Technology
Abstract
In the present study, titanium nano-particles have been synthesized using chemical vapor condensation (CVC) process. Reaction of sodium and titanium tetrachloride vapors in the tube furnace resulted in the production of titanium nano-particles that were encapsulated in sodium chloride. Dried Argon gas was employed as a carrying agent. Titanium nano-particles were contained in an ethanol bath. Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) were employed for analysis and characterization of nano-particles. The size of primary particles was smaller than 100 nm and secondary particles were submicron agglomerations
The prediction of amino proton chemical shifts using optimally selected wave function
, Article Concepts in Magnetic Resonance Part A: Bridging Education and Research ; Volume 38 A, Issue 2 , 2011 , Pages 25-32 ; 15466086 (ISSN) ; Iravani, M ; Tafazzoli, M ; Sharif University of Technology
2011
Abstract
Gas phase amino proton chemical shifts in the 54 of amines have been predicted using Gauge-independent atomic orbital (GIAO) method and optimally selected wave function. The effects of electron correlation, triple-ξ valance shell, diffuse function, and polarization function on calculated amino proton chemical shifts have been investigated using factorial design as a multivariate technique. Different optimized wave functions for different groups of amines were recommended. A wave function as the best level of the theory is proposed for homologue amines covered. In this context, B3LYP/6-311+G and HF/6-311+G wave functions have been recommended as the best and the most efficient level of theory...
Fabrication and characterization and biosensor application of gold nanoparticles on the carbon nanotubes
, Article Applied Surface Science ; Volume 355 , November , 2015 , Pages 1175-1179 ; 01694332 (ISSN) ; Aghababaie, N ; Mobasheri, H ; Zand Salimi, K ; Akbarzadeh Pasha, M ; Vesaghi, M. A ; Sharif University of Technology
Elsevier
2015
Abstract
Gold nanoparticles (Au NPs) were synthesized by co-deposition of RF-sputtering and RF-PECVD from acetylene gas and Au target on the carbon nanotubes (CNTs). The CNTs were prepared by thermal chemical vapor deposition (TCVD) and Pd nanoparticles catalyst. TEM image shows that high-density and uniform distribution of Au NPs were grown on the CNTs. XRD analysis indicates that Au NPs have fcc crystal structure and CNTs have a good graphite structure. Raman spectroscopy results suggest that our sample includes double-walled CNTs. It is resulted that intensity of D-band reduces and G-band intensity raises and radial breathing mode (RBM) is changed by immobilizing of Au NPs on the CNTs. Raman...
Studying the mechanistic behavior of heavy oil displacement using a group of alkalis and surfactant mixtures
, Article Chemical Engineering Communications ; Volume 202, Issue 3 , 2015 , Pages 366-374 ; 00986445 (ISSN) ; Jadaly, A ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
Taylor and Francis Ltd
2015
Abstract
In this study, a mixture-based sulfonate-based surfactant with a novel formula capable of functioning in real oil reservoir conditions was prepared and some microscopic parameters, like its compatibility state, emulsion behavior, interfacial tension, and temperature dependency in the presence of a heavy oil sample, and two of the most popular alkalis were analyzed; then the results were compared with those of a commercial sulfate-based surfactant. The designed surfactant provided an optimum three-phase region in relatively high salinity media; however, its optimum value decreased when adding any alkaline materials; this trend was reversed for the solutions made with the sulfate-based...