eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
2017-07-01
28
3
205
219
62686
The Study of Biological Technologies for the Removal of Sulfur Compounds
F. Nazari
1
ME. Kefayati
2
J. Raheb
3
1Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Islamic Republic of Iran
2Department of Chemical Engineering, Faculty of Engineering, University of Tehran, Tehran, Islamic Republic of Iran
1Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Islamic Republic of Iran
Combustion of sulfur components of fossil fuels such as oil causes the emission of SO2 in the atmosphere and lead to the formation of acidic rain in the environment. The conventional approach for desulfurization of fossil fuels is the chemical procedure of hydrodesulfurization (HDS). However, this method has low efficiency for desulfurization of ring components of sulfur such as dibenzothiophene (DBT) that include a significant percentage of the total sulfur content of fossil fuel. biodesulfurization (BDS), is a biological method proposed for desulfurization of ring components of sulfur which is a non-destructive pathway to remove sulfur from hydrocarbons of petroleum in the mild conditions which potentially used as complementary with HDS. For industrial application of BDS, the approach needs the new challenge to enhance desulfurization activity by genetic engineering methods and bioreactor development to achieve from a fantasy technique to an industrial and reality method for reduction of sulfur from fossil fuels. In this review, we studied and evaluated the BDS and advances in the two last decades.
https://jsciences.ut.ac.ir/article_62686_502d7f2d01e5c5fc1178e85df69987b3.pdf
biodesulfurization
Hydrodesulfurization
dibenzothiophene
Fossil fuels
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
2017-07-01
28
3
221
230
62687
Synthesis of Oxazolone and Imidazolone Derivatives in Presence of H2O2 Promoted Fly Ash as a Novel and Efficient Catalyst
S. Fozooni
1
H. Khoshdast
2
H. Hassani
3
H. Hamidian
4
1 Department of Mining Engineering, Higher Education Complex of Zarand, Zarand, Islamic Republic of Iran.
1 Department of Mining Engineering, Higher Education Complex of Zarand, Zarand, Islamic Republic of Iran.
Department of Chemistry, Payam-e Noor University (PNU), 19395-4697 Tehran, Islamic Republic of Iran.
Department of Chemistry, Payam-e Noor University (PNU), 19395-4697 Tehran, Islamic Republic of Iran.
A new catalyst was prepared by promoting fly ash with hydrogen peroxide. The catalytic activity of H2O2 promoted fly ash (HPFA) was evaluated by synthesis 5(4H)-oxazolone and imidazolone derivatives under solvent free conditions. The possible mechanisms of synthesis reactions were also suggested. These proposed methods benefit in terms of low-cost catalyst, high yields, ease of workup, survival of different functional groups, reusability of the catalyst and short reaction time. These advantages render HPFA to be a promising catalyst for synthesis of organic materials.
https://jsciences.ut.ac.ir/article_62687_032c8d4b19ffd7406a57d3547b1a0e31.pdf
Imidazolone
microwave irradiation
Oxazolone
H2O2 promoted fly ash
Solvent-free
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
2017-07-01
28
3
231
241
62688
Estimating the Mechanical Properties of Travertine Building Stones Due to Salt Crystallization Using Multivariate Regression Analysis
A. Jamshidi
1
M.R. Nikudel
2
M. Khamehchiyan
3
A. Zalooli
4
H. Yeganehfar
5
1Department of Geology, Faculty of Basic Sciences, Lorestan University, Khorramabad, Islamic Republic of Iran
2Department of Geology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Islamic Republic of Iran
2Department of Geology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Islamic Republic of Iran
2Department of Geology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Islamic Republic of Iran
3Department of Geology, Faculty of Basic Sciences, Payame Noor University, Tehran, Islamic Republic of Iran
Salt crystallization is one of the most powerful weathering agents that may cause a rapid change in the mechanical properties of stones, and thus limit their durability. Consequently, determining the mechanical properties of stones due to salt crystallization is important for natural building stones used in marine environmental and mild climatic conditions, which expose excessive salt crystallization cycles. In this study, multivariate regression analysis was performed for estimating the mechanical properties of travertine building stones after salt crystallization test. For this purpose, 12 travertine samples were selected and their physical and mechanical properties (density, porosity, uniaxial compressive strength, Brazilian tensile strength, and P-wave velocity) were determined. Then salt crystallization test was carried out at sodium sulfate solution (Na2SO4) up to 50 cycles and, after every 5 cycles, the uniaxial compressive strength, Brazilian tensile strength and P-wave velocity of the samples were measured. Using data analysis, regression equations were developed for estimating the mechanical properties of deteriorated samples at any cycle of the salt crystallization test. In these equations, the mechanical properties of the samples after salt crystallization were considered to be the dependent variable, which is dependent on the independent variables of the number of salt crystallization cycles, initial mechanical properties of the stones and their porosities. The validity of the equations was verified with the mechanical properties data of a researcher for salt crystallization test. The results showed that regression equations are in good accuracy for estimating the mechanical properties of stones, and thus making a rapid durability assessment.
https://jsciences.ut.ac.ir/article_62688_17609998eee079dff8ce5674638ce093.pdf
Salt crystallization
Uniaxial compressive strength
Brazilian tensile strength
P-wave velocity
regression equations
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
2017-07-01
28
3
243
253
62689
Characterizing Tourmaline in Metapelitic Schists from The Gasht Area, North Iran and Boron Source in Metamorphic Fluids
M. Moazzen
1
R. Michaeli
2
M. Ahangari
3
U. Altenberger
4
1-Department of Earth Sciences, Faculty of Sciences,University of Tabriz, 51664, Tabriz, Islamic Republic of Iran. 2-Research Institute for Fundamental Sciences (RIFS), 51664, Tabriz, Islamic Republic of Iran
1Department of Earth Sciences, Faculty of Sciences,University of Tabriz, 51664, Tabriz, Islamic Republic of Iran
3Department of Geology, Faculty of Sciences ,University of Urmia, Urmia, Islamic Republic of Iran
4Institut für Erd und Umweltwissenschaften, Universität Potsdam, 14476 Potsdam, Germany
Metapelitic rocks in the Gasht area include micaschist, kyanite schist, andalusite schist, garnet schist, staurolite schist, cordierite schist and sillimanite schist. Tourmaline occurs as accessory mineral in all of these rock types. These schists are metamorphosed regionally and are affected by contact metamorpism subsequently. Based on the textural relations and the fact that CaO and TiO2 contents in the studied tourmalines are low, they are formed during regional metamorphism. They appear in the rock matrix and as inclusions in other minerals, especially biotite and albite. The studied tourmalines are of alkali type and are rich in dravite end-member. Cl and F contents are below the detection limit testifying for hydro-tourmaline nature of the studied minerals. Na and K are higher in the X-site in comparison with Ca. Low Ca shows neglegible amounts of Ca end-member or uvite. Mg content is much higher than Fe in the structure of the studied tourmalines, which are not zoned or show weak zoning and are grown at nearly constant P-T conditions. These tourmalines are crystallized from pelitic to psammitic protoliths in equlibrium with a fluid phase, rich in Al. Boron in fluid more likely was from the boron adsorbed on clay minerals surface in the protolith, released during metamorphism and boron from B-bearing mica breakdown during high tempertaure metamorphism, while boron released from the subducting oceanic crust is not a likely source for tourmaline crystallization in the studied rocks since there is no evidence for tourmaline in the associated oceanic crust mafic rocks.
https://jsciences.ut.ac.ir/article_62689_5ae136eb41ec7d0b743ae4f91f4b8c03.pdf
Tourmaline
Dravite, Metapelites, Metamorphic Fluids
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
2017-07-01
28
3
255
265
62691
Urgonian Type Microfossils of the Dariyan Formation, from Southwest of Iran (Northeast of Shiraz)
M. Yavari
1
M. Yazdi
2
H. Ghalavand
3
M. H. Adabi
4
Department of Geology, Faculty of Science, University of Isfahan, 81746, Isfahan, Islamic Republic of Iran
Department of Geology, Faculty of Science, University of Isfahan, 81746, Isfahan, Islamic Republic of Iran
Third Central Building, National Iranian Oil Company, Tehran, Islamic Republic of Iran
Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran. Islamic Republic of Iran
The Lower Cretaceous Carbonate deposits of the Dariyan Formation of the HighZagros Belt are mainly composed of thick to medium bedded limestone. These depositscontain abundant and diversified benthic foraminifera which have been recovered fromcarbonate rocks. A rich assemblage of microfossils with characteristic: Palorbitolinalenticularis (Blumenbach), Mesorbitolina subconcava (Leymerie), Mesorbitolina texana(Roemer), Mesorbitolina parva (Douglass) Pseudocyclammina hedbergi (Maync),Archalveolina reicheli (de Castro), Praechrysalidina infracretacea Luperto Sinni,Chofatella decipiens (Schlumberger), Debarina hahonerensis (Fourcade, Raoul et Vila),Rumanoculina ponticuli (Neagu), Rumanoloculina pseudominima (Bartenstein etKovatcheva), Istriloculina cf. elliptica (Iovcheva) indicate paleoenviromental conditionsof shallow water carbonate sedimentation and Urgonian type facies. Based onmicrofossils distribution and biozones identification in study sections, the age of theDariyan Formation is assigned late Barremian-early Albian. The microfossilsassemblages are regarded to be comparable with the Urgonian-type fauna known fromthe peri-Mediterranean Tethys in the Barremian-Albian time interval.
https://jsciences.ut.ac.ir/article_62691_52b755e2d8dd070ebc4b806c1740bedd.pdf
Cretaceous
Dariyan Formation
Foraminifera
Urgonian
Zagros
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
2017-07-01
28
3
267
272
62692
Detecting Outliers in Exponentiated Pareto Distribution
M. Jabbari Nooghabi
1
Department of Statistics, Faculty of Mathematical Sciences, Ferdowsi University of Mashhad, Mashhad, Islamic Republic of Iran
In this paper, we use two statistics for detecting outliers in exponentiated Paretodistribution. These statistics are the extension of the statistics for detecting outliers inexponential and gamma distributions. In fact, we compare the power of our test statisticsbased on the simulation study and identify the better test statistic for detecting outliers inexponentiated Pareto distribution. At the end, we describe an example from insurancecompany.
https://jsciences.ut.ac.ir/article_62692_ae2f31235ddfef633c71de761922cecf.pdf
Exponentiated Pareto sample
Z statistic, Dixon’s statistic
Outliers
Upper outlier
eng
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
2345-6914
2017-07-01
28
3
273
285
62693
Hypercube Bivariate-Based Key Management for Wireless Sensor Networks
I. Qasemzadeh Kolagar
1
H. Haj Seyyed Javadi
2
M. Anzani
3
Department of Mathematics and Computer Sciences, Faculty of Basic Sciences, University of Shahed, Tehran, Islamic Republic of Iran
Department of Mathematics and Computer Sciences, Faculty of Basic Sciences, University of Shahed, Tehran, Islamic Republic of Iran
Department of Mathematics and Computer Sciences, Faculty of Basic Sciences, University of Shahed, Tehran, Islamic Republic of Iran
Wireless sensor networks are composed of very small devices, called sensor nodes,for numerous applications in the environment. In adversarial environments, the securitybecomes a crucial issue in wireless sensor networks (WSNs). There are various securityservices in WSNs such as key management, authentication, and pairwise keyestablishment. Due to some limitations on sensor nodes, the previous key establishmenttechniques are unsuitable for WSNs. To overcome these problems, researchers proposeseveral key pre-distribution schemes. Our proposed approach uses a combinatorialframework in the hypercube-based (HB) scheme to pre-distribute keys to each sensornode. By this way, the number of common keys between two nodes in a wirelesscommunication range increases. Therefore, the level of security in terms of resilienceagainst node capture attack and the probability of re-establishing an indirect key will beimproved.
https://jsciences.ut.ac.ir/article_62693_cba2efa457a241a1934f1d26aa09e9d7.pdf
Wireless Sensor Network
Key pre-distribution
Hypercube
Balanced incomplete block design (BIBD)
Dynamic key path discovery algorithm