Showing 8 results for Mortezaei
Volume 6, Issue 20 (6-2018)
Abstract
Khaqani is a poet of Arrani style (Azerbaijani), and one of the most prominent features of this style is the use of various tools to make the discourse difficult. Having benefited from a reach cultural background besides a deep understanding of science and technology of his own era, Khaqani has created the magnificent images and has avoided any obscenity in his words. In other words, this diversity and variety in his poetic images may be due to the extent of Khaqani's information, research and his knowledge of historical interpretive books. One of the tools used by this poet to create his own images is allusion which can be considered a featured style of Khaqani due to its high frequency in his Divan. In his allusions, Khaqani occasionally refers to the indications which we cannot find their resources and references in the official and written literature; therefore we should search folk and oral narratives to find those references. In this research, we intend to look at the sources of some Shahnameh allusions of Khaqani which are based on oral and folk narratives and they are not mentioned in the official and written sources.
Volume 9, Issue 1 (12-2017)
Abstract
Sakestan has always been an important region during the Sassanian era. The mints of this region have been the most active of all in Iranshahr from the reign of Khosrow I to Khosrow II, demonstrating the full dominance of Sassanians over Sakestan. After the death of Khosrow II, the mints of the region were inactive intermittently. A coin from the reign of Ardashir III which is currently kept in Hazrat Masumeh Museum of Qom is the only gold coin found of this king and the first with the mint mark of Sakestan. In this research, apart from studying this coin and comparing the findings with archeological data from the late Sassanian period in Sakestan, the political situation of southeastern Iran after Khosrow II has been explored using the archeological and historical data. This paper is considered an original research concerning its objective, and a historical and analytical-descriptive research in terms of its methodology and context. Data and information gathering were carried out in the field and library. Based on the results of this study, it seems that Sakestan region was under the control of the main branch of Sassanian dynasty, loyal to Khosrow II during the late Sassanian period. The importance of this study is that it can clarify the political status of southeastern Iran in the late Sassanian period based on new findings.
Volume 10, Issue 3 (12-2010)
Abstract
Abstract
Due to its simplicity, the structural engineering profession uses the nonlinear static analysis or
pushover analysis. Modeling of such analysis requires the determination of the nonlinear properties of
each component in the structure, quantified by strength and deformation capacities depending on the
modeling assumptions. Pushover analysis is carried out for either user-defined nonlinear hinge
properties or default-hinge properties, available in some programs based on the FEMA guidelines.
While such documents provide the hinge properties for several ranges of detailing, the programs may
implement averaged values. The user needs to be careful; becduse the misuse of default-hinge
properties may lead to unreasonable displacement capacities for existing structures. This paper studies
the possible differences in the results of push-over analysis due to default and user-defined nonlinear
component properties. Four- and eight-story buildings were considered to represent low- and mediumrise
buildings for this study.
Plastic hinge length and transverse reinforcement spacing were assumed as effective parameters in the
user-defined hinge properties. The observations showed that plastic hinge length and transverse
reinforcement spacing have no influence on the base shear capacity, while these parameters have
considerable effects on the displacement capacity of the frames. The comparisons pointed out that an
increase in the amount of transverse reinforcement improves the Frames displacement capacity. Also
Our findings clearly showed that the user-defined hinge model is better than the default-hinge model
in reflecting the nonlinear behavior compatible with the element properties. However, although the
default-hinge model is preferred due to its simplicity, the user should be aware of the circumstances
provided in the program and thus should avoid the misuse of default-hinge properties.
Habib Sarsangi Aliabad, Abolfazl Naji, Seyed Reza Seyed Mortezaei, Iman Sourinejad, Arash Akbarzadeh,
Volume 10, Issue 3 (9-2021)
Abstract
Biofloc technology has mentioned as a new tool for sustainable aquaculture development and has overcome the problems of water scarcity and discharge of aquaculture effluents to the environment. In this system, nitrogenous wastes (Ammonia and Ammonium) are simultaneously recovered by bacteria and converted into microbial proteins that can be consumed by aquatic animals. The purpose of this study was to investigate the factors affecting the production of biofloc and evaluate it for use in aquaculture. The effect of different temperature levels (24, 28, 32 °C), salinity (0, 4, 8 g/l) ,and C/N ratio (10:1, 15:1, 20:1) which are the main key factors to the formation and function of biofloc system was evaluated by using a response surface method designing. Moreover, the influence of those factors on total ammonia nitrogen, nitrite, nitrate, floc volume, protein, and lipid content of biofloc was investigated. The results showed that the temperature had a significant effect on floc volume and protein content of biofloc (P < 0.05), but it had no significant effect on other nitrogenous compounds and lipid content (p > 0.05). The protein, lipid and moisture of biofloc particles were decreased by increasing salinity significantly (P < 0.05). Also, TAN and nitrite concentration influenced by C/N ratio inversely. According to the factors Optimization, providing 27 °C and C/N ratio of 18:1 in brackish water and 29 °C and C/N ratio of 14:1 in fresh water resulted in high quality biofloc production and control of nitrogenous wastes in water.
Faezeh Mortezaei, Bahram Falahatkar, Mir Masoud Sajjadi, Roghieh Safari,
Volume 12, Issue 4 (12-2023)
Abstract
The objective of this study was to evaluate the performance of nutritional programming on growth and hematological indices of sterlet sturgeon (Acipenser ruthenus) during the larval stage by partial replacement of fish meal (FM) with soybean meal (S). Sterlet sturgeon with initial mean weight of 0.32 ± 0.01 g were randomly distributed into twelve circular concrete tanks (260 fish per each tank) and fed four experimental diets with substitution levels of 0 (control/FM), 15% (S15), 30% (S30) and 45% (S45) of fish meal with soybean meal during three phases in three replicates. In phase 1 (programming), fish were fed four different diets for 28 days. All the groups were then fed with FM during phases 2 (intermediate) and S45 at phase 3 (challenge) for 28 days. At the end of each phase, growth indices were measured. Hematological indices including red blood cell, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were assessed at the end of the challenge phase. The growth performance was not significantly different in either phases 1 or 2 (P > 0.05); however, final weight, weight gain, specific growth rate, and average daily growth were significantly higher in S45 than FM during phase 3 (P < 0.05). Moreover, no significant difference was indicated among the groups in hematological indices (P > 0.05). According to the obtained results, early nutritional programming could effectively enhance the adaptation of sterlet sturgeon to plant-based protein later in life.
Volume 15, Issue 1 (5-2015)
Abstract
One of the strengthening methods in reinforced concrete frame buildings is improving seismic behavior of such structures by means of steel bracing. When influenced by compressive stresses, traditional steel braces would buckle and are free of any ductility. As a result, efforts in order to restrain buckling problem for steel braces has led to creation of steel unbonded brace. In these braces, Eulerian buckling of central steel core is controlled by placing in a steel tube full of mortar. In this paper, RC buildings of 6, 12 and 18 stories are first designed based on standard 2800 and then controlled based on the rehabilitation regulation and the third edition of standard 2800. After analyzing and in order to improve seismic behavior, these buildings are strengthened by the use of common braces and steel unbonded braces and the columns of braced frames are also reinforced by concrete jacket. Totally, 42 models were analyzed by nonlinear static analysis (pushover analysis). The results indicate that structures with traditional braces have weakness in high level of drifts due to buckling of compressive braces and the energy absorption in 12 and 18 stories structures is even lower than non-strengthened structures. Nevertheless, this defect is removed by applying unbounded braces because of somehow identical behavior in extension and pressure as well as utilizing total capacity of these kinds of brace. Also, in comparison with structures with traditional braces and non-strengthened structures, a high level of energy absorption will be obtained. One of the strengthening methods in reinforced concrete frame buildings is improving seismic behavior of such structures by means of steel bracing. When influenced by compressive stresses, traditional steel braces would buckle and are free of any ductility. As a result, efforts in order to restrain buckling problem for steel braces has led to creation of steel unbonded brace. In these braces, Eulerian buckling of central steel core is controlled by placing in a steel tube full of mortar. In this paper, RC buildings of 6, 12 and 18 stories are first designed based on standard 2800 and then controlled based on the rehabilitation regulation and the third edition of standard 2800. After analyzing and in order to improve seismic behavior, these buildings are strengthened by the use of common braces and steel unbonded braces and the columns of braced frames are also reinforced by concrete jacket. Totally, 42 models were analyzed by nonlinear static analysis (pushover analysis). The results indicate that structures with traditional braces have weakness in high level of drifts due to buckling of compressive braces and the energy absorption in 12 and 18 stories structures is even lower than non-strengthened structures. Nevertheless, this defect is removed by applying unbounded braces because of somehow identical behavior in extension and pressure as well as utilizing total capacity of these kinds of brace. Also, in comparison with structures with traditional braces and non-strengthened structures, a high level of energy absorption will be obtained.
Volume 19, Issue 6 (June 2019)
Abstract
In this study, a constitutive equation based on the hyperbolic sine Arrhenius-type model has been developed to describe the hot deformation behavior of a Fe-17Cr-7Ni (17-7PH), semi-austenitic precipitation hardening stainless steel. The experimental data obtained from hot compression tests at 950-1100°C and strain rates of 0.001-1 s-1 establish the constitutive equation. The material constants of α, A, n, and Q were calculated, using the developed model related to the applied strain by 6 The average error (AARE) and correlation coefficient (R) were used to evaluate the accuracy of the constitutive equation. The average values obtained for AARE and R were 5.17% and 0.9904, respectively. The results indicated that the developed constitutive equation can predict the flow stress behavior of the studied alloy with good accuracy over a wide range of experimental conditions. The model can be, therefore, recommended for analysis of hot deformation mechanism and microstructure evolution.
Volume 23, Issue 5 (9-2021)
Abstract
The aim of this study was to evaluate the effects of feed supplemented with different levels of Selenium Nanoparticles (SeN) on growth, survival, and biochemical indices of
Acanthopagrus latus. Yellow-tail seabream fish with a mean weight of 52±3 gwasfed with four experimental diets containing 0, 0.5, 1, and 2 mg kg
-1 SeN for 8 weeks. At the end of the experiment, the fish fed 0.5 mg kg
-1 SeN showed a significant improvement of weight gain compared to the control (P< 0.05). Specific growth rate, feed conversion ratio, and survival were not significantly different between treatments (
P> 0.05). The lowest activity of alkaline phosphatase, alanine amino transferase, creatinine phosphokinase and cholesterol were observed in 0.5 mg kg
-1 SeN treatment, which was significantly lower than the control (P< 0.05). Although aspartate amino transferase, lactate dehydrogenase, triglyceride and creatinine were not significantly different among experimental treatments (P> 0.05), total protein and albumin levels were significantly increased in the 1 and 2 mg kg
-1 SeN treatments compared to the control group. The highest level of globulin was observed in the 2 mg kg
-1 SeN treatment. According to the results, the addition of 0.5 mg kg
-1 SeN to fish feed could improve growth and biochemical parameters.
