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Abstract The prediction of active earth pressures is essential to the design of retaining walls in case of reinforced and unreinforced soils. In this study, a new analytical method is presented to determine the coefficient of earth pressure. The horizontal slice method is used to compute the active earth pressure behind a rigid retaining wall in consideration of the granular soils. To verify the correctness of the suggested method, its results were compared with those of existing studies. Results show that the developed formulation for non-cohesive soils has a good agreement with the results of software simulations. Also, a new formulation for cohesive soils was presented and its results were compared with the Rankine method. The effect of parameters such as the cohesion of soil mass, the angle of internal friction and the angle of wall friction were assessed. In all cases, it is shown that the horizontal slice method has good capability to predict the active earth pressure.

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Abstract-Two-fluid models are the most accurate and complex models for analysis of two-phase flows. There are two different two-fluid models for analyzing compressible isothermal two-phase flows which are Single Pressure Model (SPM) and Two-Pressure Model (TPM). In spite of capabilities of these models in capturing two-phase flow behavior, it is not possible to express them in conservative form due to existence of non-conservative term in momentum equation of phases. Therefore, the classical Rankine-Hugoniot condition across discontinuities in the flow filed is not applicable for these equations and there would be difficulty in using classical numerical methods for solving these equations. In this paper a new path-conservative method is used to overcome this difficulty. In this method, one can apply general Rankine-Hugoniot condition along a path connecting left and right states of the discontinuity. After expressing path-conservative form of the employed central numerical methods which are Lax-Fridriches, Lax-Wendroff and Rusanove, water faucet and large relative velocity shock tube problems are solved by using these schemes. Grid independence was achieved using different grid sizes. For water faucet problem, comparison of numerical results with analytical solution show good agreement and for shock tube problem, the results indicate that this method is highly capable in capturing discontinuities in two-phase flow.

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In recent years using steel plate shear wall system, because of its advantages in comparison with other earthquake resistant systems, has been a matter of attention. Some of its advantages relative to other systems include abundance advantage, high ductility, good hysteretic behavior and energy absorption capacity, high stiffness and economic advantages. Regarding that in Iran there is high seismicity risk and the need to strengthen old and unsafe urban textures and buildings, using this system as a lateral load resistant system seems appropriate and economical. In the present research strengthening of x-braced steel frames with steel plate shear walls is evaluated. Addition of bracing to unbraced frame spans, substituting braces with thin steel shear wall panels and adding thin steel shear wall panels to unbraced spans which do not have architectural requirements are considered as retrofitting strategies. The focus is on the methods in which retrofitting is only done by adding steel plate shear wall elements to braced frames. Some of these methods have many economic and practical advantages. Others are only proper for some special cases. In this study a number of x-braced steel frames designed by the first edition of Iranian code of practice for seismic resistant design of buildings (Iranian Standard No. 2800) are taken as basic frames which need to be retrofitted. These basic frames are retrofitted by adding steel panels with different methods. Then nonlinear static analysis (pushover analysis) with displacement control pattern has been done on both basic and retrofitted finite element frame models and the capacity curves (diagram of story displacements against base shear) of basic frames and retrofitted frames are compared. Considering the results of the pushover analysis of models in which seismic retrofitting is done by replacing x-bracing earthquake resistant system with steel plate shear walls and the results of other methods of strengthening, it is seen that seismic behavior of retrofitted frames is more desirable in terms of overstrength factor (Ω) and overall ductility of structure ( ). The failure and fracture mode in most of the medium-rise frames was ductile but in the short-rise frames the fracture was brittle. Thus, replacing the braces in short-rise structure with thin steel shear walls seems irrational and unjustified economically. But it is to be mentioned that strengthening and increasing the moment of inertia of the adjacent columns of steel shear wall panels in structures with brittle fracture mode could result the change from brittle to ductile fracture. The results of this research show that in the case of steel braced frames with regard to some scientific, technical and practical points; replacing concentric steel bracing earthquake resistant system by steel plate shear walls can be used as a suitable method for retrofitting a wide range of existing steel structures in Iran.

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In this paper; reduced order modeling (ROM) of unsteady two-phase flows is performed based upon two-fluid models and a proper-orthogonal decomposition (POD) method. The four-equation two-phase flow model is used as a mathematical model to describe physics of the problem. After presenting the governing equations, direct numerical solution of the problem is introduced using AUSMDV* method. Then, the POD method is introduced as a mathematical tool to reduce computational time of the transient problems. In the present research, an equation free/Galerkine free POD method is used for ROM of the unsteady two-phase flows. In this approach, the singular value decomposition (SVD) method is used to compute the base vectors of the reduced space. A shock tube and water-air separation two-phase problems are solved using the present ROM method. Results show that this approach can reduce computational time of unsteady simulations about 35%. Reduction of the computational time directly depends on the size of the computational gird. The results also indicate that application of POD method on the fine grids is more efficient than on the coarse grids.

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Field experiments were conducted to investigate the effects of sowing dates and irrigation on seed quality of a spring-type safflower cultivar, in Karaj-Iran, during 2008 and 2009 growing seasons. A split plot design based on a randomized complete block layout with three replications was used in which sowing dates and irrigation treatments comprised the main plot and sub-plot, respectively. The results showed the highest oil yield, oil content, protein yield, and linoleic acid content of safflower seed for sowing date of 19^th of April and under non-water stress conditions. The highest seed protein, oleic acid, and palmitic acid contents were obtained for sowing dates of May 5^th and 20^th along with ceasing irrigation at heading, flowering, and seed filling stages, respectively. Under arid and semiarid Mediterranean conditions prevailing in Karaj, late sowing date led to a greater simultaneity of reproductive stages and higher temperature, which made the negative effect of water stress more prominent than in the early sowing dates.

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In the present research, the high-order DG-ADER method is used to solve governing equations of two-phase drift flux model. The drift flux model is suitable for studying two-phase flows where the phases are strongly coupled. This model is composed of three differential equations including two continuity equations for two phases and a mixture momentum equation. The mixture model uses also an algebraic relation to link the velocity of the phases. The high-order DG-ADER numerical method, which is a new scheme to get high order accuracy of results, is used to solve the governing equations. The DG-ADER is a nonlinear method in which the reconstruction process is performed using WENO method and the time evolution part is achieved by discontinues Galerkine approach. The results are compared with those reported by other researchers. Three problems including two two-phase shock tubes and a pure rarefaction test problem are solved using this method. The results show that DG-ADER method can solve the two-phase flow problems with a very good accuracy even on a coarse grid. The drawback of this method is presenting numerical fluctuations with limited domain at the position of shock waves.

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In this paper, gas-liquid two-phase flow in the annulus of a real well during under-balanced drilling operations is simulated numerically. Oil and gas flow from the reservoir in to the annulus is considered due to under-balanced drilling condition. A numerical code based on one-dimensional form of steady-state single pressure two-fluid model in the Eulerian frame of reference is developed and its results are validated using experimental data from two real wells. The results of numerical simulation show better accuracy in comparison with other researches. Given the importance of prediction and control of the bottom-hole pressure and the amount of oil and gas production during the drilling operations, the effects of controlling parameters such as liquid and gas injection flow rate and choke pressure are discussed. Also, the effects of different controlling parameters on the characteristics of two-phase flow pattern, including liquid and gas void fractions, liquid and gas velocities and pressure distribution along with the annulus are discussed. According to the results, the effects of choke pressure and injected liquid flow rate on the production of the oil from the reservoir are independent of the values of each other and are dependent on the injected gas flow rate.

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In this study, the effects of geometrical parameters of 6-DOF Hexa parallel robot on kinematic, and dynamic performance indices are investigated and its structure is optimized using the intelligent multi-objective Bees Algorithm. In this way, after describing the structure and specifying the geometrical parameters of the robot, inverse kinematic relations of the robot are obtained. Jacobian matrix that maps velocity from joint space to Cartesian space is developed. Mass matrix is obtained from calculating the total kinetic energy of the manipulator in terms of the actuated joints vector. Inverse of the homogen jacobian based condition number is considered as a index to evaluate the kinematic dexterity. based on mass matrix as relation between acceleration vector of the end effecter and torque vector of actuated joints, dynamic dexterity index is presented. Using the multi-objective Bees Algorithm and considering dynamic and kinematic performance indices in a pre-determined workspace as the objective functions, structure of Hexa parallel robot is optimized. In this way, the proper geometrical constraints such as limitation of universal and spherical joins, and the constraints to singularity avoidance are considered. Pareto front of the multi objective optimization of the robot is drawn. Diagrams of the kinematic and dynamic performance indices variation in the workspace and the effects of geometrical parameters variation on them are presented.

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Berangan banana were treated with hot water at 50 ºC for 0 (control), 10, and 20 min and then kept at room temperature (25±2 ºC), 75-80% RH to observe the ripening progress. Firmness and activity of cell wall degradation enzymes such as polygalacturonase (PG), pectin methylesterase (PME), and pectate lyase (PL) were determined for treated and untreated banana. The microstructure of banana peel cell wall was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Treated fruit was firmer than the control fruit during ripening process. PG, PME, and PL activities were reduced in the treated bananas when compared with the control treatment. Hot water treatment disturbed cell wall degrading enzymes activity and delayed the disassembling of pectin fraction of Berangan banana. The micrographs of SEM and TEM exhibited lower changes in cell compartment and less loosening of cell wall fibril fractions in treated fruits. The electrolyte leakage in Berangan banana decreased with the increase of exposure time. The results of this study indicated that hot water treatment at 50 ºC slowed down the ripening process and extended shelf lifeof banana.

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The purpose of this research is design of solar panels for a satellite which put in to geostationary orbit considering siutable reliability. The process of solar panel design is conducted according to the Design Structure Matrix (DSM) method. In this regard, an initial plan, a subsequent design process improvement, and a final optimized design process are provided. The first level of designed mechanism product tree includes released mechanism, development mechanism, lock and rotation components. Given the importance of ensuring the proper operation of mechanisms in space and reported mission failures due to lack of mechanism’s operation, the reliability network of designed mechanism is constructed and the reliability of designed panel is calculated. The amount of achieved relaiability is then verified according to the mission and system engineering requirements. Nessecary changes are applied on initial design to achieve into the satisfactory reliability for whole solar mechanism. In this regard, the critical paths in reliability network which lead to reduced reliability are investigated, and improvement of the critical path are proposed, to the extend of increasing reliability by discarding redundant components for critical parts.

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Recycled asphalt chips after shaving are considered to be a waste material that has an adverse environmental impact on the environment. On the other hand, the heavy cost of constructing new ways and damages caused by the destruction of existing roads will cause many problems. Therefore, the aim of this study was to investigate the effect of mixed bitumen with filler change on mechanical and functional properties of asphalt foam mixtures of recycled materials. Research method is field study. All experiments were carried out at the Technical and Mechanical Laboratory of the Ministry of Construction in Tehran.  In this project, aggregates consumed from asphalt tracks of the 29th straight Shahid Dastgheib International Airport in Shiraz were prepared. The bitumen used in this research was selected as bitumen from Tehran refinery in Tehran. Also, Portland cement fillers of type 425-1, lime and cement and lime mixture as active filler were used and the amount of active filler added in all designs was considered the same. Samples were made by adding cement fillers, lime with different bitumen content and under dry and saturated treatment conditions. Samples were made with filler cement (1.5%), lime (1.5%) and cement, lime (0.75% and 0.75%) and a control sample. Then, the experiments were performed on the modulus of resilience, the strength of the marshall and the indirect pull resistance. To increase the number of observations and increase the accuracy of the mathematical model, samples with cement filler with a ratio of 1 and 2 percent with bitumen 1, 2 and 3 were constructed using Marshall Hammer. Marshall Strength tests, modulus of resistivity and indirect pull resistance were carried out in dry and saturated conditions. Using the results of the modulus of resilience test, the finite element modeling was performed using ABAQUS and KenLayer software, and the effect of changing the modulus on the number of load repetitions that resulted in fatigue failure was evaluated. Finally, a mathematical model was presented. The results of this study, using SPSS and Statisca software, show that in Marshall's strength test, in all plans, increasing the bitumen from 1 to 2 percent, the Marshall Strength increases and then decreases with increasing bitumen by 2 to 3 percent. Marshall Strength ratio (obtained by dividing the Marshall strength of saturated samples to the Marshall strength of dry specimens) revealed that these types of mixtures are sensitive to moisture conditions and at best (2% bitumen and with cement lime filler) this amount reaches 0.46.  Also, results of indirect resistance test show that, with increasing bitumen from 1 to 3%, in all designs, indirect resistance is increased during drying, saturation is continuously increased.  The cement filler with lime in all treatment modes has the greatest effect on increasing the indirect pull resistance, and the effect of increasing the strength of the filler-containing specimens is more than dry in terms of saturation processing.  The results of three-dimensional modeling of Abacus showed that increasing the modulus of the base layer, the number of repetitions leads to fatigue failure greatly increases. Also, half-life parameters, expansion ratio and index of bitumen were measured and the parameters of these parameters were plotted against water percent.

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In order to investigate the effect of GABA postharvest treatment on storage life and nutritional quality of fresh cut button mushroom, mushrooms treatment with five concentrations (0, 0.01, 0.1, 1 and 10 mM) of GABA done, and stored in the refrigerator for 15 days at a temperature of 4 °C and a relative humidity of 90±5 %, and the mushroom were sampled on days 0, 5, 10 and 15. The results showed that the concentration of 1 mM GABA had a greater effect on reducing the browning index of fresh cut button mushrooms than other concentrations of GABA. Reduction of electrolyte leakage and accumulation of malondialdehyde was observed in fresh cut mushrooms treated with a concentration of 1 mM GABA, which reduced weight loss in these mushrooms. High activity of phenylalanine ammonialyase enzyme in mushroom treated with 1 mM GABA increased the content of phenolic compounds which was associated with decreased activity of polyphenol oxidase enzyme. An increase in antioxidant capacity was observed in 1 mM GABA-treated mushrooms, which was accompanied by a significant increase in ascorbic acid accumulation in these mushrooms. Therefore, GABA as a safe and effective method can be used to increase the shelf life of fresh cut button mushrooms.

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Selection based on the traits affecting grain yield is used for its indirect improvement. The objective of the present study was to determine the quantity and mechanism of effects of agro-morphological and physiological traits on grain yield of bread wheat under terminal drought conditions. Thirty six advanced lines of wheat were evaluated in a Randomized Complete Block Design with three replications during three sequential growing seasons 2010-2013 under rainfed conditions. Stepwise regression, path analysis, and canonical correlation analysis were conducted. All three components of yield had a significant positive effect on grain yield. The first canonical variable of predictive traits (U₁) and yield components (V₁) were studied. In general, selection for shorter vegetative stage and longer grain filling period is recommended to improve wheat grain yield per plant under rainfed conditions. Also, the desirable lines were those that had high amounts of biomass, average plant height and spike length, and low amount of canopy temperature. These types of lines are expected to produce higher numbers of grain per plant (not per spike) and 1000-grain weight, simultaneously, and thus higher grain yield per plant.
 

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The Maragheh observatory site was excavated in 1970. Prior to the excavation, there was very little known about this architectural masterpiece. The observatory was constructed on the top of a hill called "Rasad Dāghi". In fact, Samarkand and Jaipur observatories had derived the idea and astronomical units from the Maragheh construction. So, we can use those as comparisons while aiming to better understand and interpret the existing works in order to properly reconstruct the Maragheh observatory. Compared to similar monuments in India, the Maragheh observatory can be renovated only using the Maragheh architectural units. Comparing existing evidence of observation, including archaeological, historical and scientific evidence, will lead us to better understand the realities of the original design. With the reference to the architecture of the existing ancient observatories, the hypothesis was that through a comparative study, an architectural algorithm/pattern could be found and used to determine the shape and arrangement of the Maragheh observatory. The main objective here is to compare the historical and archaeological evidence of Iran's observation instruments with other countries in order to develop the knowledge of Archaeoastronomy. The sky and astronomical phenomenon provided the tools for time reckoning, calendar organization and celestial navigation that supported those human voyages.

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This research examines the optimization of expansion loops in steam pipeline systems using a neuro-fuzzy network. Stress analysis was conducted based on the ASME B31.3 design code using CAESAR II software. Additionally, a neuro-fuzzy network was developed and optimized in MATLAB. The results indicate that the neuro-fuzzy network outperforms traditional methods and the MLP neural network. Combining this network with the Bee Colony Optimization algorithm led to the identification of an optimal loop that minimizes pipeline length and reduces static and thermal stresses. The optimized loop obtained from the Perceptron network increased the loop length by 20 cm (1.14%) and reduced the total sum of standard stresses by 14.6%. In contrast, the optimized loop from the neuro-fuzzy network reduced the loop length by 120 cm (6.78%) and decreased the total sum of standard stresses by 9.5%. These findings demonstrate that the application of artificial intelligence techniques in expansion loop design significantly reduces thermal stresses and enhances design efficiency