s.a. razavi

Buckling restrained braces (BRBs) have gained significant popularity in advanced engineering due to their high ductility and nearly identical behavior under tension and compression. A key advantage of BRBs lies in the flexibility to adjust the length of the brace core, allowing for independent selection of stiffness and strength. In this research, carbon fiber reinforced polymer (CFRP) is employed as an alternative to steel encasing in reduced length buckling restrained braces. The proposed design incorporates the reduced length BRB as a metallic damper at the end of the brace within the frame. The elastic portion is designed to remain elastic under tension with a safety factor and to prevent overall buckling under compression. By reducing the length of the BRB, its stiffness increases, and the post-yield stiffness becomes significantly higher compared to conventional BRBs. To evaluate the performance of this brace, two types of tests were conducted. In the first test, a reduced length BRB specimen with a concrete encasing and CFRP was subjected to a uniaxial load. In the second test, a complete brace specimen with a short buckling restrained portion and the rest of brace was subjected to cyclic loading. The results demonstrate that using CFRP instead of steel encasing facilitates the prefabrication of these braces and leads to desirable seismic behavior and proper energy dissipation.

This paper discusses a special situation in project management in which an analyst wants to prioritize several independent activities to handle all them one after another, in such a way that there are no precedence relationships over the activities. As a novel idea, in this research, the notion is that the structure of prioritized activities is a linear arrangement, and therefore it could be taken into account as a combinatorial optimization problem. The paper formulates a mathematical model, develops a row-generation solving procedure, and reports the computational results for the problem instances of size up to 300 activities. The results demonstrate the applicability and efficiency of the proposed methodology.

Buckling-Restrained Braces (BRBs) are one of the new seismic resistant systems. The cross-sectional area and length of the BRB brace is one of the most important characteristics of these braces that directly affects the cost of BRB frames. Since beams, columns, and connections are designed for the maximum forces developed in BRB, the decrease in cross-sectional area of the BRBs decreases the steel consumption in the whole structure.The main purpose of this study is to optimize the weight of the structure, BRBs weight while uniforming the drift profile by changing the cross-sectional area and the length of the BRBs using genetic algorithms and other multi-objective optimization algorithms. Optimization is based on the results of nonlinear time history analysis under seven earthquake records using OpenSEES software. For this purpose, the objective function and constraints were defined in the genetic algorithm NSGA_II, MOPSO, MOEA_D, PESA_II, SPEA_II, and the initial population produced was entered as the initial cross-sectional area and length of the braces in the OpenSEES software. The optimization results show that for all three objective functions, the optimization values with high percentages of structural performance were optimized in such a way that the weight of BRB can be decreased up to about 50%.

In order to yield comparison of eight cold barley promising lines including CB-85-19,CB-85-14, CB-85-9, CB-85-15 and CB-85-10 along with three barley varieties checks(Bahman, Makoui, valfager), these experiments were conducted using RCBD withthree replications in farmer field of Torbat-e-haydaria and Fariman during 2010-2011cropping season.During the stages of growth and development, the necessary records of agriculturaland morphological traits, including the dates of spike emergence, physiologicalmaturity, plant height and 1000 seeds weight, were evaluated and after harvesting,weighing and recording the seed yield of each line, variance analysis was carried out.A randomized complete block design was performed based on the grain yield. Theresults of combining analysis showed that there were significant differences (P< 0.05)between two experimental locations for grain yield and 1000 kernels weight. Inaddition, there was a significant difference for interaction of genotype × location on1000 kernels weight. The highest grain yield (6.242 t/ha) related to CB-85-10 barleygenotype which was produced from farmer’s field in Torbat-e-haydaria and Fariman.

A better understanding of the dynamic behavior and seismic performance of structures has led to advances in structural design in recent years, but despite recent advances, many existing structures are not earthquake resistant. Steel Moment Resisting Frames (SMRFs) are one of the common structural systems in construction that has been considered by engineers due to its ease of implementation, relatively good seismic behavior and architectural considerations. However, Steel Moment Resisting Frames, in addition to being costly and performing defects in joints, has a low lateral stiffness compared to other strong systems and does not have good resistance to high horizontal displacement and structural and non-structural elements are exposed to damage. Near-fault Earthquakes are among the factors that increase damage to the structure and also intensify lateral load intensity. In this paper, the seismic behavior of SMRFs with and without Steel Plate Shear Walls (SPSWs) against 40 artificial near and far fault seismic records are evaluated using nonlinear time history analysis. For this purpose, 8-, 15- and 20- story frames were designed without considering the permissible drift criteria. Then, a steel shear wall was added to the frames and while redesigning, the drift criterion was met. The results show that in both cases with and without SPSWs the need for seismic near the fault sequences is greater than the far fault seismic sequences. The presence of SPSWs reduces the need for deformation (except for absolute floor acceleration), and this effect is more pronounced for near faults scenarios. In all cases, the presence or absence of SPSWs has no effect on the maximum floor acceleration. Adding SPSWs always increases the need for base shear force, but the force is still more significant from near fault than far fault scenarios. The results of comparing the effect of successive earthquakes near and far from the fault show that near-fault earthquakes always act to increase the need for the structure.

In this article, to study the effect of pulse-type near-fault earthquakes on the seismic demands of steel moment frames, 15-story 2D-frame was analyzed under the influence of 20 near-fields with forward directivity effect and 2 far-field records. The relationship between Effective Cyclic Energy, ECE and displacement demands, velocity and hysteretic curve of SDOF systems in two near- and far-fault earthquake was evaluated. Then, by examining the relative and absolute cumulative input energy history along with the kinetic energy in one section and the maximum inter-story drift for 4 different levels of nonlinear behaviour (R = 1.0, 2.0, 4.0, and 6.0) in a section, the effect of higher modes was evaluated. The study of inter-story drift profile for two near-fault earthquakes with and without visible pulse indicated the formation of maximum drift concentration, IDRmax, in the upper stories for low nonlinear degrees in record with visible pulse, which itself is an indication of its effect on higher mode contribution. However, in the pulse-free records, in addition to IDRmax intensification in the upper stories, the lower stories also have large structural demands. In other words, in these records, in the lower stories, mainly the dynamic instability is involved.

One of the most important effective parameters in earthquake, is behavior factor, which is depends on various factors such as structural geometric properties, structure ductility (performance level), fundamental period of the structure, damping, soil properties, earthquake characteristics (near- or far- field) and effect of higher modes. The most important feature of the behavior factor is that it allows the structural designer, to be able to evaluate the structural seismic demand, using an elastic analysis, based on force-based principles quickly. In seismic codes such as the Standard 2800, this coefficient is merely dependent on the type of lateral resistance system and is introduced with a fixed number. However, there is a relationship between the behavior factor, ductility (performance level), structural geometric properties, and type of earthquake (near fault and far fault). The purpose of this paper is to establish an accurate intelligent model related to the geometrical characteristics of the structure, performance level and the behavior factor in eccentrically steel frames, under earthquakes near-fault. For this purpose, genetic algorithm is used. Initially a wide database consisting of 12960 data with 3-, 6-, 9-, 12-, 15- and 20- stories, 3 column stiffness types, and 3 brace slenderness types were designed, and analyzed under 20 pulse-type near-fault earthquakes for 4 different performance levels. To generate the proposed model, 6769 training data were used in the form of adaptive-neural fuzzy inference system (ANFIS). Subtractive clustering and Fuzzy C-Mean clustering (FCM) methods have been used to generate the purposed model. The results showed that Fuzzy C-Mean clustering provides more accurate results than the other fuzzy inference system (FIS). To validate the proposed model, 2257 test data were used to calculate the mean squared error of the model. The results of correlation analysis of the proposed model show that the proposed intelligent model has high accuracy.

The use of the concept of earthquake input energy under far-filed earthquakes and types of internal energy in structures has recently been mentioned to develop the performance-based design method. However, the extension of these studies to near-fault pulse-like earthquakes has been less considered. This paper calculates the applied ratios of energy types in the E-SDOF and MDOF systems and identifies the relationship between them. For this purpose, five steel frames (4, 10, 15, 20, and 30 story steel MRFs with 3-span) were designed, and obtained the E-SDOF structure equivalent to the first mode, using modal pushover analysis (MPA) method. All models were analyzed under 10 near-fault pulse-like earthquake records using nonlinear time history analysis. The results show that the total dissipated energy of the structure (TDE) depends on its nonlinear degree and period. The TDE of the MDOF and E-SDOF systems is equal for long periods, and its size is independent of the design resistance (R) and the degree of nonlinearity. However, in short periods, this ratio is close to the effective modal mass coefficient corresponding to the first mode. The story normalized hysteretic energy ratio is also a function of the height, nonlinear degree and period of the structure.

Recognition of learning and study strategies is a fundamental step for educational interventions, especially in the field of medical sciences. This study aimed to determine the relationship between learning and study strategies with Academic performance of dental students of Babol University of Medical Sciences. This descriptive cross-sectional study was carried out on 85 dental students were randomly studied. The second edition of the Learning and Study Strategies Inventory (LASSI) was completed by students after the confirmation of its validity and reliability. For ten area of motivation, attitude, time management, anxiety, concentration, study guide, self-examination, study strategies, main idea choose, time management, data were analyzed using independent t-test and variance and Pearson correlation test. Among the mean scores gained by students, the highest one obtained from ten areas (27.65 ± 5.39) was related to the main idea and the least one (14.88 ± 4.35) was related to the level of anxiety. There was no statistically significant difference between sex and study strategies. (P=0.05) There was positive and strong correlation between study strategies and learning with academic performance. (r=0.52) It seems, post graduate dentistry students need to be guided in some study strategies areas. Particularly, in anxiety area, which has positive and significant correlation.

Salivary glands are the most important of the mouth internal secretory.saliva contains many useful enzymes that help in the digestive process.there are for major salinery glands in cats,including the mandibular,sublingual,parotid,and zygomatic galnd. Adenocarinomacan affect any of these salivary glands in cats,but the major target of this tomur in cats in the parotid gland.sublingual mass of a cat with clinical sign such as dysphagia,saliva drooling, anorexia and weight loss removed by surgical operation and sent for the histopathological evaluation. in microscopic observation:tumor of a glandular epithelium was seen.acinar cells had been established a solid and adenoid pattern.Malignansy sings,including mitotic formation,hyperchromatism and pleomorphism were clearly visible in nucleus of the neoplastic cells.clinical and histopathological finding reveals an acinic cell adenocarcinoma and in our knowledge,this is the first report of this kind of tumor in salivary gland of a cat.