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Showing 92 results for Type of Study: S

Hamid Nassery, Rouhollah Adinehvand, Abdalrahim Salavitabar,
Volume 13, Issue 4 (2-2014)
Abstract

Tabriz plain with area of 869 square kilometers is a part of the Urmieh lake's catchment. The purpose of this study is to simulate the behavior of Tabriz aquifer against various stresses and determine the permissible level for the operation of the aquifer. To achieve the above objective the system dynamics simulation method has been used.
In this regard, the required information includes ground water resources data (wells, springs, qanat), sources and consumptions after analysis to eliminate defects was given to the VENSIM PLE+ software, and a dynamic simulation model was developed. Then by define the range of allowed water table fluctuations and the allocation of extracted water under these conditions, the allowable water level and safe yield of the aquifer was determined.
According to the obtained results in the six-year modeling period, the maximum amount of monthly and annual extraction without any damage from the aquifer is 12.70 and 152.45 million cubic meters respectively. The average of minimum and maximum allowable water table level during this period are 1317.35 and 1322.34 meters respectively.
H Amani,
Volume 14, Issue 1 (4-2014)
Abstract

The petroleum industry generates large amounts of solid and semisolid wastes known as oily sludges. Oily sludges can be generated in several steps of the petroleum production and refining in the bottom of tanks. The accumulation of oily residues in petroleum industry poses aserious environmental problem.The aim of this research was to evaluate an alternative process of removal of oily sludge from storage tanks that can be carried out by using biosurfactants. One of the most important properties of biosurfactants is reduction of surface tension and formation of oil/water emulsions. In this research, the ability of Pseudomonas aeruginosa PTCC 1570 to produce rhamnolipid was shown and the production of rhamnoilipd was confirmed by TLC and HPLC analysis. The rhamnolipid production started at exponential growth phase and continued during the stationary phase. During investigation of rhamnolipid production on sunflower oil as sole carbon, the results showed that the maximum rhamnolipid reached about 0.5 g/l. Finally, crude oil recovery from an oil storage tank using produced rhamnolipd was also demonstrated at CMC concentration. An oil recovery of up to 70 % was obtained in a storage tank using this method.
Seyed Lotfollah Sharifi, Hadi Sadeghi, Akbar Mirzaei,
Volume 14, Issue 1 (4-2014)
Abstract

In this study, manganese dioxide nanoparticles were synthesized in the pores of zeolite 13X by supporting method and its morphology and structure were characterized by SEM, XRD, IR and AAS techniques. Decontamination reaction of 2-chloroethyl ethyl sulfide (a mustard agent simulant) was investigated by GC technique. The results of GC analysis showed that 2-CEES was completely absorbed by Nano-MnO2/Zeolite13X composite after 168 hours and converted to less toxic chemical product. Decontamination products formed via hydrolysis were hydroxyl ethyl ethyl sulfide and ethyl vinyl sulfide. Destruction reaction of DMMP nerve agent simulant via 31P NMR analysis showed that this composite after 36 hours demolished almost 32 percent of nerve agent simulant
Zhaleh Ebrahimi, Ali Asghar Shokri,
Volume 14, Issue 1 (4-2014)
Abstract

in this paper, the effect of rough interface is investigated on spin dependent transmission in a magnetic tunneling junction. For calculating of transmission probability the transfer matrix technique and the approximation of effective mass is used in calculations.  The mentioned magnetic structure includes of two semiconductor ferromagnetic separated by a nonmagnetic layer which is attached to two metal nonmagnetic electrodes. The different components of spin dependent  transmission probability (direct and indirect)   in the presence of roughness is studied while the roughness is distributed as random islands in interfaces. The results of calculations show that roughness  affects the transport of incident electrons through mentioned double barrier structure, effectively. Because the scattering due to roughness of interface and therefore opening addition conduction  channels, results to reduce the peak of incident electrons transmission probability. Also, the effect of percent of interface roughness is studied on component of indirect  transmission probability. 
Behzad Mahmoudian, Mohsen Mohammadzadeh Darrodi, ,
Volume 14, Issue 2 (7-2014)
Abstract

In this article a spatial model is presented for extreme values with marginal generalized extreme value (GEV) distribution. The spatial model would be able to capture the multi-scale spatial dependencies. The small scale dependencies in this model is modeled by means of copula function and then in a hierarchical manner a random field is related to location parameters of marginal GEV distributions in order to account for large scale dependencies. Bayesian inference of presented model is accomplished by offered Markov chain Monte Carlo (MCMC) design, which consisted of Gibbs sampler, random walk Metropolis-Hastings and adaptive independence sampler algorithms. In proposed MCMC design the vector of location parameters is updated simultaneously based on devised multivariate proposal distribution. Also, we attain Bayesian spatial prediction by approximation of the predictive distribution. Finally, the estimation of model parameters and possibilities for capturing and separation of multi-scale spatial dependencies are investigated in a simulation example and analysis of wind speed extremes.
Mahmod Bahar, H Golnabi, Mahsima Hamidi,
Volume 14, Issue 3 (10-2014)
Abstract

The aim of this study was to estimate Specific Absorption Rate (SAR) induced in human head tissues, by assuming human head as a cubical model filled with lossy dielectric material and exposed to electromagnetic plane waves. The research is carried out by computational simulation using C programming codes. The numerical technique used in this study was Finite Difference in Time Domain (FDTD) method, along with Perfectly Matched Layer (PML) as an appropriate absorbing boundary condition. Different conditions including exposure conditions as well as physical parameters are employed, in order to compare the results to the past literature. Finally, the penetration depth of one of the specified models is expressed by means of interpolation. The results which are in complete agreement with the others in some cases, suggests that considering the biological tissues as dispersive media, would result in correct estimations whereas changing in the structure of the model, doesn’t differ if precise predictions are not important. Furthermore, the penetration depth correlation to frequency is in line with what is expressed in theoretical papers.
H Amani,
Volume 14, Issue 4 (6-2015)
Abstract

In this research, the ability of Pseudomonas aeruginosa NP2to produce rhamnolipid biosurfactant was investigated. Rhamnolipid has various applications in oil industry including cleaning oil sludge filters, cleaning oil storage tanks and biological treatment of oil wastes.The purpose of this paper was optimization of biosurfactant production for reduction of costs using taguchi experimental design methods. Source of carbon, salt concentration, phosphorus concentration and nitrogen concentration at three levels were investigated. The best condition for biosurfactant production was observed when sucrose was used as carbon source, 50 g/l Nacl as salt source, 6.75 g/l NaH2PO4 as phosphorus source, and 1g/l (NH4)2SO4 as nitrogen source. The highest rhamnoliopd production among different experiments was 2.8 g/l. Also the evaluation of emulsification index (E24) of the produced rhamnolipid was studied and the emulsification index value of 80% was reached for crude oil (API=34).
N Samadani, V Jodaeian,
Volume 14, Issue 4 (6-2015)
Abstract

The aim of this study is to investigate the possibility of the using rice bran as a natural and suitable adsorbent for the removal of formic acid whose is an organic acid from liquid solution and the effect of various parameters such as adsorbent dose, initial concentration adsorbate, temperature and time on the adsorption process and determination of adsorption isotherm constants. Removal of organic acids from liquid solutions is an important environmental challenge. Batch adsorption experiments showed that the adsorption increased with the increasing of the amount of adsorbent, initial concentration of adsorbate and decreasing temperature and adsorption process is reached the equilibrium state after one hour. The adsorption data was analyzed using the various isotherm models. From these various isotherm models, the adsorption process obeys the Langmuir and Freundlich adsorption isotherms. The results show a good agreement with both methods.The average amount of adsorbate per 3 degrees of freedom and confidence 95% ، 10.39±0.095 ، is obtained
Salman Ahmady-Asbchin, Naser Jafari,
Volume 15, Issue 1 (4-2015)
Abstract

Abstract
Methods of physical and chemical adsorption of heavy metals, has some disadvantages such as high cost and are ineffective at low concentrations. Methods for biological uptake of heavy metals in recent decades were considered. Among the biological adsorbent include: bacteria, fungi and alga, algae have the highest efficiency of metal uptake. This study determined that the main role in the uptake of metals, nickel (II) and cadmium (II) Alginic acid is responsible. Focus serratus brown alga, as adsorbent in this study used a cost-effective biological and biological uptake of cadmium and nickel ions simultaneously in a batch reactor has been studied. Surface structure of algae has been studied. Adsorption kinetics have been studied, the equilibrium time is about 300 minutes, the Langmuir adsorption isotherm using the equation can be interpreted as the maximum adsorption of about 0/85and 0/95mmol/g are, respectively, for cadmium(II) and nickel(II).
G Rabani, R Ezati,
Volume 15, Issue 1 (4-2015)
Abstract

Acid rain, which is a wet form of gaseous air pollutants, is formed when air pollutants such as SO2, NO2, CO2 in atmosphere combine with water vapor of clouds. With the addition of concentration of these pollutants the amount of acid rain is increases. Acid rain that is the mixture of sulphuric acid, nitric acid and carbonic acid lead to change in the soil like the decrease in pH, nutrient liberation, the increase of releasing in toxic metals and the decline in fertility of soil that these cases results negative effects on plants. In present work wheat plants irrigated  and leaf spraied with  four treatments of acid rain which contain sulphuric acid and nitric acid with  pH= 2.5, 3.5, 4.5, 5.6 for a period of 32 days, whereas, control plants irrigated and leaf spraied by normal water at  pH= 7.4 . According to the results control plants in whole of growth and physiological indexes were better than treatments of  acid rain at pH= 2.5 and 3.5, also plants of acid rain treatment at pH= 4.5 and 5.6, were lower in other factors except photosynthetic rate, pigment content and carbohydrate content than control plants. Also acid rain at pH= 2.5 and 3.5 causes white spot in both surface of  leaf and tip and border atrophy.
M Ranjbar,
Volume 15, Issue 2 (2-2015)
Abstract

In this research, plant morphology and pollen morphology of 14 populations of 3 species belonging to two sections Plethiosphace and Hemisphace of Salvia genus in Iran were studied. In morphological study 25 quantitative and qualitative characters were investigated and results of this study clearly separated species into two groups. The pollen grains from the herbarium specimens were prepared by acetolysis method and then 4 quantitative characters were examined by light microscopy. Data analysis was carried out by principal component analysis method. Results of the study showed that although the pollen grains in the section are comparatively homogenous and all of them are 6-colpate with reticulate ornamentation, but show a considerable variation in studied quantitative characters. However among the studied characters, equatorial and polar diameters of pollen grains are the most significant characters and based of these characters the members of these sections can be divided into two groups based on these characters that confirmed the results of morphology.
M Soltani Najafabadi, Sa. Babazadeh,
Volume 16, Issue 42 (5-2015)
Abstract

The various species of Alveolina for biostratigraphy of Eocene sedimentary rocks are very important. In this research, the species of Alveolina  are reported for the first time in three cross sections: Chalonak, Kalaterood and East Beinabad. These sections are attributes to Early- Middle Eocene age. The 55 samples collected from Chalonak section and the thickness is reached to 245 m. In this section, four biozones are distinguished. They are following: Alveolina globula-Alveolina solida interval range zone, Alveolina solida-A .globosa interval range zone, Alveolina globusa total range  zone and  Alveolina aragonesis  total range zone. On the basis of index fossils such as  Alveolinana  avellana, A. aragonensis,A. globula, A. leupoldi, A. globusa, A. elliptica nutalli, A. rotundata, A. corbarica, A.solida, which are existing in these biozones, the age of this section is attributed to Early Eocene. Of course two species of Nummulites (Nummulites globulus, N. atacicus) and Cuvilierina valensis are determined in Chalonak section. The 80 samples are collected from Kalaterood section and the thickness is reached to 242 m. In this section, four biozones are distinguished. They are following: Alveolina solida- A. globosa interval range zone, Alveolina globosa total range zone, Alveolina aragonensis-A. canavarii interval range zone and A. canavarii total range zone. The several index fossils are found in this section following: Alveolina aragonensis, A. decipiens, A. Avellana, A. laxa, A. pasticillata, A. canavari, A . globosa and A. solida. The age of this section is Early Eocene.  The 150 samples are collected from East Binabad section and the thickness is reached to 900 m. In this section, four biozones are presented. They are Glomalveolina   lepidula – Alveolina solida interval rage zone. Alveolina elliptica nutali- Alveolina corbarica interval range zone, Alveolina corbarica total range zone and Alveolina ruetimeyeri-Alveolina levantina assemblage zone. There are several index fossils such as Alveolina corbarica, A. elliptica nuttalli, A.levantina,  A. roetimeyeri  and  A. decipiens, Glomalveolina lepidula. The age of this section is early Eocene.
F Noori Sandbani, H Azizi,
Volume 16, Issue 42 (5-2015)
Abstract

Gabbroic bodies with NW-SE trend outcropped in the southwest of Sahneh in the north of Gamassiab River, W. Iran are part of Zagros ophiolite . This complex is separated from the other geological units by deep faults and cut by pyroxenitic dikes. The field evidences, petrographic, geochemical and mineral paragenesis of these rocks are completely different from the fresh and un-altered gabbroic rocks. Furthermore the high ratios of 143Nd/144Nd (0.512945-0.513021) and low ratios of 87Sr/86Sr (0.70334-0.70656) indicate the sub-oceanic depleted mantle source for the origin of these rocks. Low variation of 143Nd/144Nd ratios, increasing of 87Sr/86Sr ratios, decreasing of SiO2 and increasing of CaO and Al2O3 mainly concludes the high reaction of gabbroic rocks with seawater. The pargenetic assemblages of altered gabbros are grossular/hydrogrossular, anderadite, epidote, idocrase (vesuvianite) and diopside. The mineral paragenesis reveals that the rodingitization was occurred by reaction of gabbroic bodies with high alkali water at a shallow depth
Azhdar Soleymanpour Bakefayat, Nader Dastranj,
Volume 17, Issue 40 (9-2015)
Abstract

In this paper, We Stabilize a subclass of nonlinear control systems by using neural networks and Zobov's theorem. Zobov’s Theorem is one of the theorems which indicates the conditions for the stability of a nonlinear systems with specific attraction region. We applied neural networks to approximate some functions mentioned in Zobov’s theorem, So as to find the controller of a nonlinear controlled system which is difficult task to find its law in mathematic manner. also we apply nelder meed optimization method to learning neural network. Finally, the effectiveness and the applicability of the proposed method are demonstrated by using some numerical examples.
Nasrin Mahdianfard, Mohsen Mohammadzadeh,
Volume 17, Issue 40 (9-2015)
Abstract

Linking between geographic information systems and decision making approach own the invention and development of spatial data melding methods. Data melding methods combine the data, to achieve a better result and their aim is, to detect the information available in the data set in order to enhance the ability of interpreting data and increase the accuracy of the data analysis. In this paper, Bayesian melding method has been studied for combination of measurements, outputs of deterministic models and kriging methods. By spatial Bayesian melding and kriging an attempted is made to spatial prediction of ozone data in Tehran and results are validated and compared using the mean square error criterion.

Volume 18, Issue 55 (6-2001)
Abstract

Olibanum (Frankincense) is a plant resin, which could be obtained from Boswellia carerii and some species of genus Boswellia. Survay in the field of Iranian and Islamic medicine customy indicating that most former and recent medicine customy philosophers believe that following consumption of Olibanum, specially during pregnancy, might increase intelligence, memory and learning abilities in the children. In the present investigation, thin layer chromatography method was used to identify plant species. The main goal of this research was to determine if Olibanum extract has any effect on learning abilities as well as memory in the next generation. Twenty wirgin Wistar rats were mated and the first day of gestation was determined by observation of vaginal plaque. The pregnant animals were divided into two experiment.11 (n=7) and one control (n=6) groups. From day 10 of gestation to 10 day post -paturition, every five day, the peregnant rats were injected intraperitoneally of 0.2 ml of aqueou extraction of Olibanum (%5 and %10 in experimental groups 1 and 2 respectively). The control rats were received equal volume of normal saline. When nevborns became two months old, randomly from each litters, one male and one female were selected. A T-complex maze was used first to test learning abilities by counting their errors and also measuring the time of reaching the goal. To test the effects of Olibanum on 1ong term memory. The examined animals were left free of any test for a period or 20 days. Then, they were tested again by the same maze. The results indicating that, in comparison with control animals, administration of Olibanum aqueous extraction specially 5% solution could significantly increase (p < 0.001) the rate of learning abilities and long-term memory as well.

Volume 18, Issue 55 (6-2001)
Abstract

In this research, the effect of water stress on the soluble sugars, starch and proteins content of two different cultivars (kaka and jam) of chickpea (Cicer arietinum) was studied. The results showed that the soluble sugars increased while starch decreased during the stress in shoot and root of both cultivars. Increasing of soluble sugars and decreasing of starch hall a positive correlation with water stress. Variations of soluble sugars in two cultivars were significant, but its amount was higher in kaka than in jam. Variations of starch in tow cultivars were significant too, but its amount were higher in jam than in kaka, This may suggests that kaka is more tolerant to water stress than jam. Consideration of the electrophorogram of proteins showed the changes of protein bands under drought stress.

Volume 18, Issue 55 (6-2001)
Abstract

Ahangaran lead-silver deposit is located 25 km southeast of Malayer on Malayer Arak road. The deposit is tectonically situated in Sanandej-Sirjan zone. Mineralization in Ahangaran mine occurs between sandstone and dolomite units, which is expanded into dolomite unit. The host rock of the deposit is limestone, which is early Cretaceous in age and apparently mineralization, occurs in the same time. Ahangaran deposit has been conformed of two parts including statiform and epigenetic vein type. Studies on the minerals such as pyrrhotite, chalcopyrite, and sphalerite reveal that the veins have formed in high temperature, while the stratiform zone was formed in a low temperature sedimentary environment. Mineralogical and geological characteristics of the Ahangaran deposit indicate the deposit to be a sedimentary exhalative type and the relationships between Ag and Pb confirm this idea. As a whole it can be said that the Ahangaran deposit is a polygenetic deposit which is formed in four stages: hypogene epigenetic, hypogene syngenetic, supergene epigenetic and supergene syngenetic. volume of normal saline. When nevborns became two months old, randomly from each litters, one male and one female were selected. AT-complex maze was used first to test learning abilities by counting their errors and also measuring the time of reaching the goal. To test the effects of Olibanum on long-term memory, the examined animals were left free of any test for a period of 20 days. Then, they were tested again by the same maze. The results indicating that, in comparison with control animals, administration of Olibanum aqueous extraction specially 5% solution could significantly increase (p<0.00l) the rate of learning abilities and long-term memory as well.
1

Volume 1356, Issue 2 (8-1977)
Abstract

1
Bahare Noohi, Mansour Zahedi, Mina Ghiasi,
Volume 1356, Issue 2 (8-1977)
Abstract

The most prevalent and important mechanism of bacterial resistance to &beta-lactam antibiotics, is the production of &beta-lactamase enzymes which inactivate these drugs by the hydrolytic cleavage of the four-membered &beta-lactam ring during two steps which is including the nucleophilic attack of the bridging hydroxide ion on the substrate and eventual protonation of the leaving amine group. During this reaction, metal ions play an important role in the catalytic process. Despite the availability of &beta-lactamase crystallographic structures, their mechanism of action is still unclear and no clinically useful inhibitors of these enzymes have been reported. Density functional theory (DFT) using B3LYP and 6-31G, 6-31G* and 6-311G** basis sets have been employed to calculate the details of electronic structure and electronic energy of catalytic reaction of CcrA enzyme active center from metallo-&beta-lactamase enzymes (M&betaLs), penicillin from &beta-lactam antibiotics, and the formed complexes including ES, ETS1, EI1, EI2, ETS2 and EP respectively, has been used. Also all the thermodynamic functions including ∆Hº, ∆Sº and ∆Gº to form two transition states, ETS1 and ETS2, and for the total reaction are evaluated at 25 °C, 31 °C, 37 °C and 40 °C and 1 atmosphere pressure. In all calculations solvent effects have been considered by using PCM method for water, ethanol, protein environment, nitro methane and carbon tetrachloride. Finally this reaction proceeds during an exothermic and spontaneous process, and the first step, the nucleophilic attack of the bridging hydroxide ion on the substrate, is the rate-limiting step

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