Search for: nitrogen
Total 288 records
Novel synthesis route for preparation of porous nitrogen-doped carbons from lignocellulosic wastes for high performance supercapacitors, Article Journal of Alloys and Compounds ; Volume 827 , 2020 ; Abdolmaleki, H ; Doroudian, M ; Hosseini, S. H ; Sharif University of Technology
Elsevier Ltd 2020
Porous nitrogen-doped carbons derived from biomass wastes are considered as promising materials for energy storage devices. Herein, a novel and scalable synthesis route for preparation of these materials from sugarcane bagasse waste is demonstrated. The synthesis process includes a hydrogel intermediate in which delignified bagasse and polyacrylamide networks are interlaced in molecular scale and calcium acetate serves as a hard template within the polymeric chains. After pre-carbonization and chemical activation of the hydrogel, porous nitrogen-doped carbon with high surface area of 1834.3 m2 g−1 and considerable pore volume of 1.03 cm3 g−1 was obtained with nitrogen and oxygen contents of...
Article Synthetic Communications ; Volume 36, Issue 23 , 2006 , Pages 3599-3607 ; 00397911 (ISSN) ; DokhtTaimoory, S. M ; Ismaili, H ; Rezanejade Bardajee , G ; Sharif University of Technology
KF/Al2O3 efficiently catalyzes N-alkylation of heterocyclic, primary, and secondary amines and S-alkylation of thiols with a variety of alkyl halides. The N-alkylation and S-alkylation adducts were produced in good to excellent yields and in short times. Copyright © Taylor & Francis Group, LLC
A simple, economical, and highly efficient synthesis of β-hydroxynitriles from epoxide under solvent free conditions, Article Journal of Molecular Catalysis A: Chemical ; Volume 247, Issue 1-2 , 2006 , Pages 159-161 ; 13811169 (ISSN) ; Azizi, N ; Saidi, M. R ; Sharif University of Technology
A simple, rapid, and highly regioselective green protocols for the synthesis of β-hydroxylnitriles by the direct reaction of epoxides with trimethylsilyl cyanide in the presence of catalytic amount of lithium perchlorate under solvent free conditions in high to quantitative yield is reported. © 2005 Elsevier B.V. All rights reserved
One‐dimensional convolutional neural networks for hyperspectral analysis of nitrogen in plant leaves, Article Applied Sciences (Switzerland) ; Volume 11, Issue 24 , 2021 ; 20763417 (ISSN) ; Sabzi, S ; Rohban, M. H ; Hernández‐hernández, J. L ; Gallardo‐bernal, I ; Herrera‐miranda, I ; García‐mateos, G ; Sharif University of Technology
Accurately determining the nutritional status of plants can prevent many diseases caused by fertilizer disorders. Leaf analysis is one of the most used methods for this purpose. However, in order to get a more accurate result, disorders must be identified before symptoms appear. Therefore, this study aims to identify leaves with excessive nitrogen using one‐dimensional convolutional neural networks (1D‐CNN) on a dataset of spectral data using the Keras library. Seeds of cucumber were planted in several pots and, after growing the plants, they were divided into different classes of control (without excess nitrogen), N30% (excess application of nitrogen fertilizer by 30%), N60% (60% overdose),...
Article Scientia Iranica ; Volume 14, Issue 2 , 2007 , Pages 152-160 ; 10263098 (ISSN) ; Khorasheh, F ; Gray, M. R ; Sharif University of Technology
Sharif University of Technology 2007
Catalytic hydrocracking of topped Athabasca bitumen was investigated in a continuous stirred-basket 0reactor, using a fresh and spent commercial catalyst, as well as in the presence of no catalyst. A continuous lumping model was developed for kinetic analysis of hydrodenitrogenation and hydrocracking reactions. The normalized boiling point was used to describe the reactant mixture as a continuous mixture. The continuous model, with five adjustable parameters, was used to describe hydrocracking reactions. Reactions of nitrogen compounds were described by series reactions, involving cracking to lower molecular weight products, as well as direct denitrogenation. The model was able to accurately...
A statistical inference approach for the identification of dominant parameters in immiscible nitrogen injection, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, Issue. 12 , 2014 , Pages 1285-1295 ; ISSN: 15567036 ; Ghazvini, M. G ; Dabir, B ; Emadi, M. A ; Rashtchian, D ; Sharif University of Technology
Screening analysis is a useful guideline that helps us with proper field selection for different enhanced oil recovery processes. In this work, reservoir simulation is combined with experimental design to estimate the effect of reservoir rock and fluid properties on performance of immiscible nitrogen injection. Reservoir dip, thickness, and horizontal permeability are found to be the most influential parameters. Possible interactions of parameters are also discussed to increase reliability and robustness of screening results. Finally, significance of both main effects and interactions are evaluated by employing a statistical inference approach (hypothesis testing) and results are compared to...
Effect of the pyrrolic nitrogen functional group in the selective adsorption of CO2: GCMC, MD, and DFT studies, Article Energy and Fuels ; Volume 35, Issue 19 , 2021 , Pages 15918-15934 ; 08870624 (ISSN) ; Mirzaee Valadi, F.M ; Latifi Pour, M ; Rashtchian, D ; Gholami, M. R ; Sharif University of Technology
American Chemical Society 2021
In this paper, the pyrrolic nitrogen functional group's presence is investigated in the selective adsorption of CO2. The grand canonical Monte Carlo (GCMC), molecular dynamics (MD), and density functional theory (DFT) were used for this study's goal. GCMC was used to calculate adsorption isotherms, selectivity, and isosteric heats. MD was used to calculate the radial distribution function (RDF) and diffusion. Reactivity parameters, electrostatic potential (ESP), reduced density gradient (RDG), and independent gradient model (IGM) were calculated using DFT. Adsorption isotherms, selectivity, and isosteric heats demonstrated that the NH group caused the selective adsorption of CO2 among CH4,...
N-doped CNT nanocatalyst prepared from camphor and urea for gas phase desulfurization: experimental and DFT study, Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 85 , April , 2018 , Pages 121-131 ; 18761070 (ISSN) ; Banna Motejadded, H ; Rashidi, A ; Hamzehlouyan, T ; Yousefian, Z
Taiwan Institute of Chemical Engineers 2018
In the present work, mesoporous nitrogen-doped carbon nanotubes (N-CNTs) were synthesized by using a low-cost and unique set of precursors (camphor and urea). The CVD method at 1000 °C was used with different camphor/urea ratios, and Co-Mo/MgO nanocatalyst was utilized as growth catalyst. Application of mesoporous N-CNTs in selective oxidation of H2S was studied experimentally and N-CNTs interactions with H2S was also investigated using DFT calculations. The as-synthesized N-CNTs were characterized using FTIR, FE-SEM, elemental analysis, X-ray diffraction (XRD), XPS and nitrogen adsorption/desorption. The N-CNT2 sample with urea to camphor ratio (U/C) of 1 showed the highest sulfur yield at...
Comparison of different trophic cultivations in microalgal membrane bioreactor containing N-riched wastewater for simultaneous nutrient removal and biomass production, Article Process Biochemistry ; Volume 51, Issue 10 , 2016 , Pages 1568-1575 ; 13595113 (ISSN) ; Mehrnia, M. R ; Shayegan, J ; Sarrafzadeh, M. H ; Sharif University of Technology
Elsevier Ltd 2016
In this study, a submerged membrane was installed in a bioreactor to treat N-riched wastewater and obtain high biomass productivity. Chlorella vulgaris was cultivated under mixotrophic, heterotrophic, and photoautotrophic conditions in different kinds of nitrogen sources (nitrate and ammonium) to compare the microalgae growth and nutrient removal in a membrane bioreactor. Further, the respirometric and photosynthetic activities of microalgae were investigated to evaluate the viability of microalgae in different conditions. The highest biomass productivity was obtained under mixotrophic cultivation in ammonium source (0.230 ± 0.009 gr/L d). Moreover, with this type of cultivation and nitrogen...
An Investigation on Photocatalytic Behavior of N-doped and N-V-doped TiO2 Thin Film, Coated on Glass Surface by Sol-gel Dip Coating Method, M.Sc. Thesis Sharif University of Technology ; Faghihi Sani, Mohammad Ali
In this study, the photocatalytic activity and hydrophilicity of coat improved using Nitrogen and Vanadium elements as dopant in TiO2 coating. By using vanadium and nitrogen elements and silica prelayer, a titania coating was deposited on the soda-lime glass substrate by sol-gel dip coating method to produce self-cleaning surface. XRD and FTIR analyses were done on the powders after heat treating at in 450˚C for 30 min. XPS analysis was done for investigation of N replacement in titania structure. The band-gap energy of formed anatase was derived using UV-Vis analysis. The coating morphology and thickness were also investigated by SEM. Hydrophilicity of coatings was determined by measuring...
Optimization of biomass and biokinetic constant in Mazut biodegradation by indigenous bacteria BBRC10061, Article Journal of Environmental Health Science and Engineering ; Vol. 12, issue. 1 , June , 2014 ; Mashreghi, M ; Yaghmaei, S ; Sharif University of Technology
Optimization based on appropriate parameters can be applied to improve a process. Mazut degradation as a critical issue in environment requires optimization to be efficiently done. To provide biodegradation conditions, experiments were designed on the least interactions among levels of parameters consisting of pH, Tween 80, glucose, phosphorous source, nitrogen source, and time. Kinetic constants and biomass were calculated based on 16 assays, designed using Taguchi method, which constructed various mazut biodegradation conditions. Kinetics of mazut degradation by newly isolated bacteria Enterobacter cloacae closely followed second order kinetic model. Results of the 16 experiments showed...
Article Journal of Sulfur Chemistry ; Volume 32, Issue 4 , 2011 , Pages 335-343 ; 17415993 (ISSN) ; Zare, M ; Sharif University of Technology
The oxidation of sulfides to sulfoxides with hydrogen peroxide in good yield and high selectivity has been catalyzed very effectively by a series of Schiff base salen-type iron complexes in a monophasic medium (CH 2Cl2/CH3OH) at ambient temperature. The results of the present study show that the reaction rate strongly depends on both catalyst steric effects and steric and electronic properties of sulfides. In the system, the electronic spectral studies are applied to explain the formation of a reactive (salen) Fe=O intermediate
Simultaneously energy production and dairy wastewater treatment using bioelectrochemical cells: In different environmental and hydrodynamic modes, Article Chinese Journal of Chemical Engineering ; 2017 ; 10049541 (ISSN) ; Yaghmaei, S ; Mardanpour, M. M ; Ghasemi Naraghi, Z ; Sharif University of Technology
Chemical Industry Press 2017
A successful design, previously adapted for treatment of complex wastewaters in a microbial fuel cell (MFC), was used to fabricate two MFCs, with a few changes for cost reduction and ease of construction. Performance and electrochemical characteristics of MFCs were evaluated in different environmental conditions (in complete darkness and presence of light), and different flow patterns of batch and continuous in four hydraulic retention times from 8 to 30h. Changes in chemical oxygen demand, and nitrate and phosphate concentrations were evaluated. In contrast to the microbial fuel cell operated in darkness (D-MFC) with a stable open circuit voltage of 700mV, presence of light led to growth of...
Fate of intermediate biodegradation products of triethyl amine in a compost-based biofiltration system, Article International Journal of Environmental Research ; Volume 1, Issue 2 , 2007 , Pages 163-169 ; 17356865 (ISSN) ; Keshavarzi Shirazi, H ; Mehrdadi, N ; Sharif University of Technology
Biofiltration of Triethylamine (TEA) vapor used as a catalyst in casting operations was evaluated in this study The unit consisted of a 6-L three-stage biofilter containing a mixture of compost and wood chips (40:60 v/v) as the filter medium. Seed microbial population from municipal activated sludge was acclimated for a period of three weeks prior to the actual experimental runs. In the startup period, high pH values up to 10 was observed due to alkaline nature of TEA and inadequate formation of biofilm and low overall biodegradation. Steady increase of organic-N concentration along with gradual upward trend of pressure drop indicated sound establishment of microbial population. Operational...
Nondestructive nitrogen content estimation in tomato plant leaves by Vis-NIR hyperspectral imaging and regression data models, Article Applied Optics ; Volume 60, Issue 30 , 2021 , Pages 9560-9569 ; 1559128X (ISSN) ; Sabzi, S ; Rohban, M. H ; García Mateos, G ; Arribas, J. I ; Sharif University of Technology
The Optical Society 2021
The present study aims to estimate nitrogen (N) content in tomato (Solanum lycopersicum L.) plant leaves using optimal hyperspectral imaging data by means of computational intelligence [artificial neural networks and the differential evolution algorithm (ANN-DE), partial least squares regression (PLSR), and convolutional neural network (CNN) regression] to detect potential plant stress to nutrients at early stages. First, pots containing control and treated tomato plants were prepared; three treatments (categories or classes) consisted in the application of an overdose of 30%, 60%, and 90% nitrogen fertilizer, called N-30%, N-60%, N-90%, respectively. Tomato plant leaves were then randomly...
Article Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science ; Volume 35, Issue 5 , 2004 , Pages 937-948 ; 10735615 (ISSN) ; Sharif University of Technology
Minerals, Metals and Materials Society 2004
The effects of powder particle size on the densification and microstructure of iron powder in the direct laser sintering process were investigated. Iron powders with particle sizes ranging from 10 to 200 μm were used. It was found that the sintered density increases as the laser energy input is increased. There is, however, a saturation level at which higher density cannot be obtained even at very intensive energy input. This saturation density increases as the size of the iron particles decreases. Meanwhile fine powders with narrow particle size distributions have a tendency toward agglomeration, and coarse powders with broad particle size distributions have a tendency toward segregation,...
Inhibition effect of 3,5 bis (2-pyridil) 4-amino 1,2,4 triazole and 1-10 phenantrolin on corrosion of mild steel in acid solutions, Article British Corrosion Journal ; Volume 37, Issue 1 , 2002 , Pages 76-80 ; 00070599 (ISSN) ; Hosseini, M. G ; Ghorbani, M ; Sharif University of Technology
IOM Communications Ltd 2002
The inhibition effects of 3.5 bis (2-pyridil) 4-amino 1,2,4 triazole (NBTA) and 1-10 phenantrolin (PHEN), on corrosion of mild steel in acid solutions, (sulphuric acid and hydrochloric acid) were studied. The Tafel polarisation and ac impedance techniques were employed. Results obtained reveal that both compounds are relatively good inhibitors. The inhibition efficiencies of NBTA are higher in hydrochloric acid than in sulphuric acid. This has been attributed to the synergistic effect of chloride ions present in hydrochloric acid. The mechanism of inhibition of PHEN is believed to be owing to the formation of insoluble chelates between the organic molecules and atom/ion on the metal surface....
Article 12th International Conference on Microelectronics, ICM 2000, 31 October 2000 through 2 November 2000 ; Volume 2000-October , 2000 , Pages 209-212 ; 9643600572 (ISBN) ; Vashaei, Z ; Mahdavi, S. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2000
We compare Cu/M/SiO2 (M=Cr,V and Ta) multilayers that were deposited on Si substrates. Sample resistance measurements were carried out during annealing in 80% N2+20% H2, N2 and Ar environments. Resistivity measurements, SEM observations, RBS and AES spectroscopies from annealed samples showed good diffusion barrier properties for Cr and V but rather poor properties for Ta buffer layers. This is due to the amorphous nature of Cr films and formation of a continuous Cu overlayer. SEM observation also showed granular structure for Cu/V and Cu/Ta with grain sizes of about 500 and 1000 Å respectively. However, shallow nitrogen implantation in Cu/V samples and DC biasing for Cu/Ta layers during...
M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem
The air cathode of li-air batteries has been identified as a key factor affecting the overall performance of Li-air batteries. Graphene-based cathodes have been investigated as cathode catalysts for lithium-air batteries due to their high activity in accelerating and facilitating oxygen reduction reaction (ORR). In this study at first, graphene oxide was synthesized using Hummers’ method, and then it has been reduced via hydrothermal methode. To increase electrocatalytic properties of the sample Cobalt oxide nanoparticles has been precipitated on reduced graphene oxide, and it has also been doped with Nitrogen. Three samples of reduced graphene aerogel (GA), Nitrogen doped graphene aerogel...
Article Fuel Processing Technology ; Volume 91, Issue 7 , 2010 , Pages 714-722 ; 03783820 (ISSN) ; Mohammadi, M ; Ghorbanpour, A ; Sharif University of Technology
Coke deposition mechanism on a commercial Pt-Re/γ-Al 2O3 naphtha reforming catalyst was studied. A used catalyst that was in industrial reforming operation for 28 months, as well as the fresh catalyst of the unit were characterized using XRD, XRF, and nitrogen adsorption/desorption analyses. Carbon and sulfur contents of the fresh and the used catalysts were determined using Leco combustion analyzer. The pore size distributions (PSD) of the fresh and the used reforming catalysts were determined using BJH and Comparison Plot methods. The Comparison Plot method produced the most reasonable PSDs for the catalysts. Through comparison of the PSDs of the fresh and the used catalysts, it was...