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Estimation of the Compressive Strength of GGBFS based Alkali-Activated Concrete
, M.Sc. Thesis Sharif University of Technology ; Toufigh, Vahab (Supervisor)
Abstract
Ground granulated blast furnace slag (GGBFS) based alkali-activated concrete (GAAC) is one of the eco-friendly alternatives of traditional concrete, which uses industrial byproducts instead of ordinary Portland cement (OPC). Besides environmental benefits, substituting OPC concrete with GAAC has some economic advantages, while it successfully meets the concrete structural requirements in both mechanical and durability characteristics. Despite this fact, employing GAAC in the construction industry has been limited due to a lack of standard mix design code.This study aims to develop an accurate prediction model for the compressive strength of GAAC by employing the most appropriate machine...
Effect of Chemical Composition on Atomic Structure and Mechanical Properties of Mg-Zn Glass Alloys Using Molecular Dynamics Simulation
, M.Sc. Thesis Sharif University of Technology ; Tavakoli, Rohollah (Supervisor)
Abstract
In this research, Mg-Zn bulk metallic glasses have been investigated using molecular dynamics simulation. In order to study the structure of this alloy, coordination number, short and medium order of chemical range, Voronoi analysis, glass conversion temperature and atomic pair distribution function have been used. According to the results, the full icosahedral structure with IS connection type in comparison with other structures has an essential role in the stability of the system during cooling and creating medium-scale areas. The results show that the ability to form glass depends on the chemical composition and cooling rate. In this research, the cooling rate is considered to be 1011 K/s...
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
Electronic structure of some thymol derivatives correlated with the radical scavenging activity: Theoretical study
, Article Food Chemistry ; Vol. 165, issue , Dec , 2014 , p. 451-459 ; Jebeli Javanb, M ; Sharif University of Technology
Abstract
Molecules acting as antioxidants capable of scavenging reactive oxygen species (ROS) are of upmost importance in the living cell. Thymol derivatives exhibit various antioxidant activities and potential health benefits. Exploration of structure-radical scavenging activity (SAR) was approached with a wide range of thymol derivatives. To accomplish this task, the DPPH experimental assay along with quantum-chemical calculations were also employed for these compounds. By comparing the structural properties of the derivatives of interest, their antioxidant activity was explained by the formation of an intramolecular hydrogen bond and the presence of unsaturated double bond (–CHdouble bond; length...
Spectrophotometric determination of sulfide based on peroxidase inhibition by detection of purpurogallin formation
, Article Ecotoxicology and Environmental Safety ; Volume 91 , 2013 , Pages 117-121 ; 01476513 (ISSN) ; Kariminia, H. R ; Roosta Azad, R ; Sharif University of Technology
2013
Abstract
This paper presents a new method for spectrophotometirc detection of sulfide applying fungal peroxidase immobilized on sodium alginate. The sensing scheme was based on decrease of the absorbance of the orange compound, purpurogallin produced from pyrogallol and H2O2 as substrates, due to the inhibition of peroxidase by sulfide. Absorbance of purpurogallin was detected at 420nm by using a spectrophotometer. The proposed method could successfully detect the sulfide in the concentration range of 0.6-7.0μM with a detection limit of 0.4μM. The kinetic parameters of Michaelis-Menten with and without sulfide were also calculated. Possible inhibition mechanism of peroxidase by sulfide was deduced...
Modeling and stability analysis of truncated high density lipoprotein (HDL) system using MARTINI coarse grain technique
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Volume 3 A , November , 2013 ; 9780791856215 (ISBN) ; Rouhollahi, A ; Sohrabi, S ; Mehr, S. M. N ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2013
Abstract
Lipoproteins are biochemical compounds containing both proteins and lipids. These particles carry chemicals like cholesterol and triglycerides that are not soluble in aqueous solutions. This paper presents modeling of lipoprotein system using coarse grain molecular dynamics technique and stability analysis of this system in a water solution like blood. A high density lipoprotein (HDL) that consists of two annular monomers is modeled. Also there are lipid bilayers located in center of the rings, so the whole HDL and lipid bilayers are called lipoprotein system. First, all atom model is provided and then coarse-grain model is obtained using MARTINI technique. Modeling of the system in all atom...
A quantitative structure-property relationship for determination of enthalpy of fusion of pure compounds
, Article Journal of Thermal Analysis and Calorimetry ; Volume 109, Issue 1 , June , 2012 , Pages 501-506 ; 13886150 (ISSN) ; Gohar, M. R. S ; Vayeghan, M. G ; Sharif University of Technology
2012
Abstract
In this study, the quantitative structure-property relationship method is applied to predict the enthalpy of fusion of pure chemical compounds at their normal melting point. A genetic algorithm-based multivariate linear regression is used to select the most statistically effective molecular descriptors for evaluating this property. To propose a comprehensive and predictive model, 3,846 pure chemical compounds are investigated. The root mean square of error and the average absolute deviation of the model are equal to 2.57 kJ/mol and 9.7%
Reinforced polydiphenylamine nanocomposite for microextraction in packed syringe of various pesticides
, Article Journal of Chromatography A ; Volume 1222 , January , 2012 , Pages 13-21 ; 00219673 (ISSN) ; Ayazi, Z ; Es'haghi, A ; Aghakhani, A ; Sharif University of Technology
2012
Abstract
Reinforced polydiphenylamine (PDPA) nanocomposite was synthesized by oxidation of diphenylamine in 4molL-1 sulfuric acid solution containing a fixed amount of carbon nanotubes (CNTs) in the presence of cetyltrimethylammonium bromide (CTAB). The surface characteristic of PDPA and PDPA/CNT nanocomposites was investigated using scanning electron microscopy (SEM). The prepared PDPA/CNT nanocomposite was used as an extraction medium for microextraction in packed syringe (MEPS) of selected pesticides from aquatic environment. The effect of CNT doping level and the presence of surfactant on the extraction capability of nanocomposite was investigated and it was revealed that when 4% (w/w) of CNT in...
Prediction of standard enthalpy of combustion of pure compounds using a very accurate group-contribution-based method
, Article Energy and Fuels ; Volume 25, Issue 6 , April , 2011 , Pages 2651-2654 ; 08870624 (ISSN) ; Mirkhani, S. A ; Tofangchi Mahyari, A. R ; Sharif University of Technology
2011
Abstract
The artificial neural network-group contribution (ANN-GC) method is applied to estimate the standard enthalpy of combustion of pure chemical compounds. A total of 4590 pure compounds from various chemical families are investigated to propose a comprehensive and predictive model. The obtained results show the squared correlation coefficient (R 2) of 0.999 99, root mean square error of 12.57 kJ/mol, and average absolute deviation lower than 0.16% for the estimated properties from existing experimental values
Prediction of absolute entropy of ideal gas at 298 K of pure chemicals through GAMLR and FFNN
, Article Energy Conversion and Management ; Volume 52, Issue 1 , 2011 , Pages 630-634 ; 01968904 (ISSN) ; Bagheri, M ; Ghaniyari-Benis, S ; Aslebagh, R ; Kamaloo, E ; Sharif University of Technology
2011
Abstract
Thermodynamical optimization for energy conversion system can be performed by decreasing entropy generation. For calculation of entropy, we need to know entropy of ideal gases at 298 K as a reference point. Entropy is a thermodynamic quantity which is not easily measured and prediction of entropy by molecular structures for new designed molecules may be a challenge. An easy and accurate equation for prediction of absolute entropy of pure ideal gas at 298 K was introduced for the first time based on the quantitative structure property relationship (QSPR) approach. Thousand seven hundred pure chemical compounds and 3224 molecular descriptors were used for finding this easy equation by genetic...
Supercritical synthesis and in situ deposition of PbS nanocrystals with oleic acid passivation for quantum dot solar cells
, Article Materials Chemistry and Physics ; Volume 156 , 2015 , Pages 163-169 ; 02540584 (ISSN) ; Simchi, A ; Aashuri, H ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Colloidal quantum dot solar cells have recently attracted significant attention due to their low-processing cost and surging photovoltaic performance. In this paper, a novel, reproducible, and simple solution-based process based on supercritical fluid toluene is presented for in situ growth and deposition PbS nanocrystals with oleic-acid passivation. A lead precursor containing sulfur was mixed with oleic acid in toluene and processed in a supercritical fluid condition at different temperatures of 140, 270 and 330 °C for 20 min. The quantum dots were deposited on a fluorine-doped tin oxide glass substrate inside the supercritical reactor. Transmission electron microscopy, X-ray diffraction,...
Investigation of photocatalytic performance of TiO2 network and fiber geometries
, Article Desalination and Water Treatment ; Volume 57, Issue 50 , 2016 , Pages 23644-23650 ; 19443994 (ISSN) ; Sadrnezhaad, S. K ; Kheilnejad, A ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
In typical photocatalytic processes slurry reactors are used in which catalyst particles have to be separated from the solution after the process ends which means much higher time and costs. Hence, immobilizing process is carried out on the catalyst to overcome this problem. In this work, fiber and network geometries were produced by particle precipitation on substrates. The obtained structures were characterized by XRD, SEM, and Brunauer–Emmett–Teller analyses. Photocatalytic performance of the samples was investigated by methyl orange degradation and also by hydrogen generation from water/methanol splitting. From the SEM images, the size range of the TiO2 particles in the network...
Biocatalysts in microbial electrolysis cells: A review
, Article International Journal of Hydrogen Energy ; Volume 41, Issue 3 , 2016 , Pages 1477-1493 ; 03603199 (ISSN) ; Mardanpour, M. M ; Yaghmaei, S ; Sharif University of Technology
Elsevier Ltd
Abstract
Microbial electrolysis cells (MECs) are bioelectrochemical reactors in which chemical energy stored in organic compounds are converted to hydrogen through biocatalytic oxidation by microorganisms. The performance of MECs is highly affected by microbial communities that are impartible parts of this technology. A better understanding of microbial interactions and competitions mechanisms, has aided the comprehension of ideas and guidelines for cost effective commercial scales design. In this study, a comprehensive review of current knowledge in the microbial characterization, enrichment, and evaluation of effective parameters of microbial community in microbial electrolysis cells for typical...
Facile one-pot synthesis of polytypic (wurtzite–chalcopyrite) CuGaS2
, Article Applied Physics A: Materials Science and Processing ; Volume 122, Issue 3 , 2016 , Pages 1-10 ; 09478396 (ISSN) ; Mirkazemi, S. M ; Tahir, M. N ; Iraji Zad, A ; Ghasemzadeh, R ; Tremel, W ; Sharif University of Technology
Springer Verlag
2016
Abstract
Abstract: In this investigation, monodisperse CuGaS2 nanoparticles intended for use as visible-light-absorbing materials were synthesized using a facile one-step heating method that involved dissolving the precursors copper chloride, gallium acetylacetonate, and thiourea in a solvent consisting of either oleylamine alone or a combination of oleylamine, oleic acid, and 1-octadecene. The shapes of the resulting nanoparticles were either elongated, polygonal, or a mixture of both, depending on whether the crystal structure of the nanoparticles was predominantly wurtzite, predominantly chalcopyrite, or a more balanced mixture of both wurtzite and chalcopyrite (i.e., the nanoparticles were...
A single–step synthesized supehydrophobic melamine formaldehyde foam for trace determination of volatile organic pollutants
, Article Journal of Chromatography A ; Volume 1525 , 2017 , Pages 10-16 ; 00219673 (ISSN) ; Zeinali, S ; Baktash, M. Y ; Sharif University of Technology
Abstract
Superhydrophobic materials have attracted many attentions in recent years while their application in sample preparation remained almost intact. In this project, a rough surface of melamine formaldehyde foam was silanized by chemical deposition of trichloromethylsilane to form a highly porous and superhydrophobic material, presumably a suitable medium for extracting non–polar compounds such as benzene and its methyl derivatives. The prepared sorbent was packed in a needle for the headspace needle–trap microextraction of benzene, toluene, ethylbenzene and xylenes (BTEX). Major parameters associated with the extraction/desorption processes were considered for optimization. Under the optimized...
Triethylamine removal using biotrickling filter (BTF): effect of height and recirculation liquid rate on BTFs performance
, Article International Journal of Environmental Science and Technology ; Volume 14, Issue 8 , 2017 , Pages 1615-1624 ; 17351472 (ISSN) ; Sotoudeheian, S ; Bayat, R ; Sharif University of Technology
Center for Environmental and Energy Research and Studies
2017
Abstract
This study investigated the removal of triethylamine using a biotrickling filter. The influence of affecting parameters, such as height and recirculation liquid rate (VL) on contaminant removal efficiency, was examined in detail. The results demonstrated that in the constant empty bed residence time (EBRT), when VL was increased, the removal efficiency (RE) increased. Also, for a specific VL, increasing EBRT could also increase RE values. However, it seems that an increasing VL is a more cost-effective way to enhance RE as compared to an increasing EBRT. The obtained outcomes represented that for a constant EBRT, an increase in inlet loading (IL) could decrease RE. For lower ILs, the removal...
Terahertz time domain spectroscopy for mixture detection: A quantitative study
, Article 4th International Conference on Millimeter-Wave and Terahertz Technologies, MMWaTT 2016, 20 December 2016 through 22 December 2016 ; 2017 , Pages 17-19 ; 21570965 (ISSN); 9781509054145 (ISBN) ; Yahyaei, B ; Kouhanestani, M. K ; Mousavi, M ; Darbani, M. R ; Majde, A. E ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
Terahertz spectroscopy is a useful and an efficient method for detection of pure materials and also mixture compounds. In the present study the terahertz spectra of the α-lactose, high explosives RDX and also the binary mixture of mentioned materials has been obtained in the transition mode. The obtained spectra of the pure materials were in a very good agreement with literatures in the range of 0.1 to 1.5 terahertz. The spectra of mixture samples which show the specific fingerprint characters of each component, declare that terahertz spectroscopy can be used effectively for the detection of explosives and chemical compounds even in the mixture samples. © 2016 IEEE
Superhydrophobic surfaces with a dual-layer micro- and nanoparticle coating for drag reduction
, Article Energy ; Volume 125 , 2017 , Pages 1-10 ; 03605442 (ISSN) ; Moosavi, A ; Nouri Borujerdi, A ; Daeian, M. A ; Vafaeinejad, S ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
We propose a facile and cost effective method for fabricating superhydrophobic surfaces with significant drag reduction in a wide velocity range. A dual structure superhydrophobic aluminum surface with a hydrophobic Al2O3micro- and nanoparticle coating and also another superhydrophobic surface with a nanoparticle layer coating are fabricated. Then, the resulted drag from each of these surfaces is measured carefully in different velocities and compared with the drag of the as-received aluminum surface. Our results reveal that the surface with the dual structure experiences drag reduction in a wider velocity range compared with the nanoparticle coated sample. Drag reduction of the dual...
Aqueous-phase reforming of glycerol for production of alkanes over Ni/CexZr1-xO2 nano-catalyst: Effects of the support's composition
, Article Renewable Energy ; Volume 108 , 2017 , Pages 417-424 ; 09601481 (ISSN) ; Kazemeini, M ; Larimi, A. S ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
The aqueous phase reforming (APR) reaction of glycerol considered to be environmentally green. It converted polyols into value added products including; H2 and alkanes. Ni species known for its capability of producing alkane-rich gas under the APR process conditions might be utilized for this purpose. In this research, the conversion of glycerol into alkanes demonstrated using 10wt% Ni/CexZr1-xO2 (with x = 0, 0.3, 0.5, 0.7 and 1) catalysts. In order to better understand the behavior of these materials, they were evaluated physio-chemically through the; XRD, BET, H2-TPR, H2-Chemisorption and TEM analyses. Moreover; performances of the synthesized materials were determined through their...
Seasonal trends, chemical speciation and source apportionment of fine PM in Tehran
, Article Atmospheric Environment ; Volume 153 , 2017 , Pages 70-82 ; 13522310 (ISSN) ; Hosseini, V ; Zare Shahne, M ; Bigdeli, M ; Lai, A ; Schauer, J. J ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Frequent air pollution episodes have been reported for Tehran, Iran, mainly because of critically high levels of fine particulate matter (PM2.5). The composition and sources of these particles are poorly known, so this study aims to identify the major components and heavy metals in PM2.5along with their seasonal trends and associated sources. 24-hour PM2.5samples were collected at a main residential station every 6 days for a full year from February 2014 to February 2015. The samples were analyzed for ions, organic carbon (including water-soluble and insoluble portions), elemental carbon (EC), and all detectable elements. The dominant mass components, which were determined by means of...