Showing 92 results for Type of Study: S
T Seifi, Mr Imanpur, Ch Makhdomi,
Volume 11, Issue 4 (2-2012)
Abstract
In this study, the effects of semen ion ratios on spermatological parameters and pH in carp were evaluated. The Spermatological and biochemical parameters from 14 males fish in the laboratory by microcentrifuge, stereomicroscope, spectrophotometer, flame photometer and ph meter were measured. Na+/K+, Na+/Ca2+, Na+/Mg2+, K+/Ca2+, K+/Mg2+ and Ca2+/Mg2+ ion ratios of each treatment were divided into three groups. The results of this study showed that sperm quality increased with increasing of Na+/K+ but decreased with increasing of Na+/ Ca2+, K+/ Mg2+ and K+/Ca2+. Also, change of ion ratios Ca2+/Mg2+ and Na+/Mg2+ has no influence on sperm quality. The refore, it can be concluded that ion ratios are effective in increase or decrease of sperm quality.
M Nabuni, Z Reesi,
Volume 11, Issue 4 (2-2012)
Abstract
Maternal alcohol abuse causes abnormal fetal development, a condition called fetal alcohol syndrome (FAS). Hydrocephalus is one of the main features accompanying this condition. The early sign of hydrocephalus in the fetal period is ventricolumegaly, followed by reduction in the cortex thickness. In this research hydrocephaly and its effect during ethanol exposure was investigated .To inducing FAS, pregnant Wistar rats were fed with 5) % w/v (liquid alcoholic diet from day 8 of pregnancy to delivery. Embryos of E18 and E19 days were decapitated and brains were removed and sectioned and stained by H&E and immunohistochemistry. The analysis of the brain sections revealed significant decrease (p
Am Shahrezaee, M Hoseini Nia,
Volume 12, Issue 1 (11-2012)
Abstract
در این مقاله سه نوع از مسائل معکوس سهموی از نوع هدایت گرمایی و تشعشع گرمایی به روش تجزیه آدومیان بررسی می شود و برای حل این نوع مسائل معکوس از یک شرط فوق ¬اضافی در یک نقطه داخلی ناحیه مفروض مسأله استفاده می شود. این روش با سرعت همگرایی بالا، تقریب عددی از جواب دقیق مسأله بدون نیاز به خطی¬سازی یا گسسته سازی می¬دهد. در واقع روش تجزیه آدومیان، نیاز به حل کردن هر سیستم خطی یا غیرخطی از معادلات جبری را از بین می¬برد. نتایج عددی به دست آمده از این روش حاکی از دقت و سرعت بالای این روش است
Ar Fakharzadeh Jahromi, N Ahmadi,
Volume 12, Issue 1 (11-2012)
Abstract
بخش مهمی از مسائل قابل هدایت در مهندسی، از جمله مهندسی شیمی، مسائل کنترلی از نوع تنظیمکننده هستند. از طرفی روشهای گرادیان مزدوج تعمیم یافته و روش نشاندن قابلیتهای توانمندی در حل این مسائل دارند. این مقاله با معرفی الگوریتم آنها برای حل مسائل کنترل بهینه، به مقایسه این دو شیوه کارا، از نظر تحلیلی و عددی خواهد پرداخت. همچنین چگونگی کاربرد آنها در محاسبه مسیر و کنترل بهینه یک مخزن هم زده شده پیوسته راکتور شیمیایی را که تا کنون از این دو شیوه حل نشدهاند، بیان و بررسی مینماید. در این راستا با بیان مثالهای عددی، مقادیر بهینه همراه با مسیر و کنترل بهینه حاصل از این روشها، مقایسه خواهند شد.
Amir Eskandari, F Masoudi, N Farahkhah,
Volume 12, Issue 2 (11-2012)
Abstract
In this research, based on spatial distribution and size of crystals, the role of physical processes affecting formation of the igneous rocks such as kinetics of crystallization (nucleation and growth of crystals), dynamics of magmatic systems (e.g. mixing and convection currents) and equilibrium processes such as textural coarsening are investigated.
To this end, the spatial distribution pattern (SDP) of plagioclase, amphibole and quartz crystals were quantified in the microdiorite-quartz diorites and results were combined with petrography to discuss the factors affecting plagioclase packing arrangements and physical processes operated during formation of these rocks. The study area is located in 120 Km southeast of Birjand. The 8 thin sections of rocks were processed and geometrical features e.g. length, width and centre of 3098 crystals were measured. Then, R values (a descriptive value) were measured using nearest neighbor distance method with BigR and ArcGIS software's and the data were plotted against porosity (modal abundance of other phases in igneous rocks.) Results show that crystals have clustered SDP. The degree of plagioclases clustering is different in sections with change of crystal sizes and shapes. The origin of crystal clusters is likely to involve heterogeneous nucleation, textural coarsening and overgrowth of crystals.
P Abdolmaleki, B Nahidian, A Paeez, F Ghanati,
Volume 12, Issue 3 (11-2012)
Abstract
There are many reports on the effects of magnetic fields on the plants, but the exact mechanisms of these effects are poorly understood. In this study we compared the effects of different magnetic fields on the germination and early growth of wheat seeds. The seeds of wheat (Triticum aestivum L.) in two groups, dry and imbibed, were treated with static magnetic field (SMF 30mT) and electromagnetic field (EMF 10KHz) for 4 days and 5 hour for a day. After treatment, seed water uptake, the percent and speed of germination, early growth characteristics and electrolyte leakage of seeds coat and seedlings root membrane were estimated. The results showed that treatment with SMF and EMF had not significant effect on the germination percent of imbibed wheat seeds, but accelerated the speed of germination, fresh and dry weight and vigor index II, compared to control groups. In dry wheat group only positive effect of magnetic field had seen on the length of seedlings. Magnetic field treatment decreased the electrolyte leakage of seeds coat and seedlings root membranes however had not increased the water uptake of seeds. So elevated speed of germination and growth of seedlings probably was due to increase of membrane integrity, content or activity of the germination enzymes or antioxidant enzymes. In general, effects of magnetic field on the imbibed seeds is better than dry seeds and SMF had better effect than EMF on the germination and early growth of wheat seedlings.
Roya Karamian, M Asadbigi, M Ranjbar,
Volume 12, Issue 3 (11-2012)
Abstract
Salvia L. is one of the important genera of the Lamiaceae family, that most of its species have nutritious and medicinal values. This study aimed to examine the total phenol and flavonoid contents and the antioxidant activities of S. aethiopis using spectrophotometric method. The essential oil of this species was analyzed using GC and GC/MS methods. In addition, antibacterial activities of the essential oil and methanolic extract were evaluated against six gram positive and negative bacteria, respectively. Results showed that the extract has high content of phenolic compounds with high antioxidant activity. From GC analysis, 11 different compounds were indentified in which &alpha-copaene was the most abundant compound with 33.48%. The extract of the species showed a high antibacterial activity against Proteus vulgaris. However, the essential oil of S. aethiopis had no effect on examined bacteria.
,
Volume 12, Issue 4 (11-2013)
Abstract
Biosurfactants are widely used in industries like oil, cosmetics, food, and pharmaceutics. Surface tension reduction, the ability to emulsify oil and high biodegradability are among the main characteristics of these biosurfactants. These favorable features make biosurfactants as potential alternatives of chemically synthesized surfactants in a variety of applications. In this research,Bacillus subtilis NLIM0110 was used to produce a lipopeptide-type biosurfactant (surfactin) in an innovative bioreactor tailored to solve the problems of severe foaming arising from production of the biosurfactant. To cope with the rapid foam generation, a conventional fermentor was integrated with a foam collector. The other aims of this study were purification, identification of surfactin, optimization of agitation rate and aeration rate which were used to increase the surfactin production. The results showed the production of biosurfactant was proportional to the cell growth representing biosurfactant as a growth-associated product. The best condition for bioreactor was 300 rpm and 1.5 vvm, giving Yp/s, Yp/x and Y of 0.595 gg&minus1, 0.25 gg&minus1, and 0.057 gl&minus1h&minus1, respectively. The production of surfactin was confirmed by FTIR and HNMR analysis.Thus, these results show the potential effectiveness of the microorganism and the technique used in biosurfactant production.
Azim Aminataei,
Volume 13, Issue 3 (11-2013)
Abstract
In this study, we simulate numerically the process of oxygen mass transport in the human circulatory system incorporating the contribution of axial diffusion. Simulated equation is a time dependent convective-diffusion partial differential equation wherein has applicable application in the bioengineering problems such as boundary layer of fluids, electrical circuits in cables and mass transport problems.
The analytical solution of this kind of equations is complicated. Therefore, the numerical solution for obtaining the approximate solution is important and the convergence and stability in this method of solution, is always a question. In this study, we try to answer the above questions with respect to this special equation and for this we use finite differences.
Alireza Sarakhsi, Mohammad Jahanshahi,
Volume 13, Issue 3 (11-2013)
Abstract
In this papear, we produce the method for formation and recognizing boundary layers in singular perturbation problems. This method involves four step for localization of non-local boundary conditions to local case.For the given problem some sufficient and necessary conditions are given for formation and non formation of boundary layers. Since the existence of boundary layers and their places has a direct relation with the structure of approximate solutions and uniform solutions, therefore the main purpose of this paper is recognition and formation of boundary layers in singular perturbation problems with non-local boundary conditions. This process will be done by using fundamental solution of adjoint given differential equation and necessary conditions.In fact by using these necessary conditions and given boundary conditions, we make an algebraic system.By solving this algebraic system by Cramer rule we obtain boundary values of unknown function.These values of unknown function are local boundary conditions.The mathematical model for this kind of problem usually is in the form
of either ordinary differential equations (O.D.E) or partial differential equations (P.D.E) in which the highest derivative is multiplied by some powers of as a positive small parameter.
Vahid Ahadnejad,
Volume 13, Issue 4 (2-2014)
Abstract
The magnetic anisotropy of rocks results from the contributions of diamagnetic, paramagnetic, & ferromagnetic minerals. This bulk anisotropy of magnetic susceptibility, which can be rapidly measured with modern instruments, generally provides a better understanding of the rock deformation history. Different minerals in a rock can form at different times and also respond to deformation in different manners. Therefore it is useful to separate their respective contributions to the whole rock magnetic fabric. Various techniques available to achieve this separation among them measurement of the magnetic properties at high fields, above the saturation magnetization of ferromagnetic minerals, effectively separates the diamagnetic-paramagnetic magnetic anisotropy. In this paper, the anisotropies of ferromagnetic and paramagnetic components are separated using High-Field Analysis torque for 37 samples of natural rocks. These samples are igneous rocks of Malayer that are mainly composed of paramagnetic minerals (e.g. biotite and amphibole) and few portions of ferromagnetic minerals (e.g. titanomagnetite) which are located in the quratz-feldespathic (diamagnetic) context. Anisotropy of Magnetic Susceptibility (AMS) in low field analyses indicated that paramagnetic phases are the dominant control of the magnetic fabric. This is confirmed by High Field Analyses (HFA) which implied that magnetic characteristics are dominated by paramagnetic minerals, except for three samples.
E Moradian Teshnizi, Mostafa Ghomashi, Ali Ahmadi, Hadi Aminrasoli,
Volume 13, Issue 4 (2-2014)
Abstract
The study area is located to the south, west and north Esfahan province. this research is geochemical and petrographic study of Lower cretaceous dolomites. Five dolomite type have been identified.
The first type is very fine-fine crystalline dolomite formed in near surface conditions and in early stages of diagenesis, in tidal flat to lagoonal environments. The Sr content is high (2537ppm) and Fe (8861ppm) and Mn (852ppm) is low.
The second type is fine-medium-grained, subhedral to euhedral, crystalline dolomites. Compared to the first type, Sr content is lower and Fe and Mn content is higher. This type of dolomites is most likely formed in early burial diagenesis.
The third type is medium-coarse-grained, euhedral and subhedral, crystalline dolomite and show clear rim and cloudy center. Compared to the type1 and type2, this type of dolomite contains higher Fe and Mn and lower Sr. They are likely formed in deeper burial diagenesis and by dolomitization of earlier calcareous deposits or recrystalization of first- and second- type dolomites.
The medium-coarse-grained, crystalline dolomite fill in pores and fractures, and are called "four-type" in this study. This type of dolomite is likely formed during late diagenesis and under conditions of medium pressure and temperatures less than 60-80 °C. In this dolomite values of Fe and Mn increase from the fringes of pores and fractures to the center.
The fifth dolomite type is coarse, crystalline, saddle dolomite filling pores and fractures. This dolomite
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