For extraordinary properties of carbon nanotube (CNT), a lot of research has been done about its application to reinforce different materials such as electronic and building materials, and good effects of CNT have been observed. Experimental approach for determining the properties of composites containing fibers, especially carbon nanotubes, needs using of complex experimental methods and expensive laboratorial equipments. Theoretical approach can lower the cost of predicting properties of these composites. So, in this paper, an analytical relation is presented by continuum mechanics method to predict the compressive strength of cement composite reinforced with carbon nanotube. For simplicity of computations, carbon nanotubes were assumed to be isotropicand firstly oriented unidirectionally and uniformly in the cement composite. Representative Elementary Volume(REV), as anindicatorelement of this nanocompositeis, was chosen and analyzed by continuum mechanics method. A fiber embedded in a cylinder of cement with certain radius is named REV. The strains under loads were calculated and the stresses were obtained by Hook’s law. Then, for prediction failure of composite, von Mises’ yield criterion was applied and by that, the compressive strength of cement composite reinforced with unidirectionally oriented carbon nanotubes was obtained. For real cases, the results of this analysis should be generalized to cement composites reinforced with random orientation of nanotubes, since there is no control on the distribution of fibers in the laboratory and they are oriented randomly in composites, although researchers are studying on production of CNT/cement composites with arbitrary orientation of fibers.To apply the random orientation effect, Cox’s method was used. For this purpose, the fiber's distribution function f () was assumed and it was observed that the random orientation of fibers reduces the effect of fiber reinforcing with respect to unidirectional orientation. Therefore, an orientation factor  1 was used considering random orientation in comparison with unidirectional orientation. As a suggestion, this factor can be experimentally obtained too. Experimental method was used to determine the orientation factor of fibers incomposites and good results were obtained. Then the presented analytical relationship was compared with experimental data. Matches and differences between the analytical method and the experimental data were studied and the suggestions were presented to lower the differences between the analytical and experimental methods. The effect of some parameters such as compressive strength of cement and the amount of carbon nanotubes added on the compressive strength of CNT/cement composite were obtained too. Accordingly that an ideal nanocomposite with regard to economical considerations can be obtained.

Tappeh Bazgir is one of the most important archaeological sites of the Late Bronze Age in northeastern Iran. At this site, a hoard of 759 Bronze Age copper-alloy objects with an approximate weight of more than two tons was excavated. This find is unique in terms of volume and the extraordinary finds it contained. This archaeological hoard was discovered by chance in 2001, and in 2010 a rescue excavation was carried out at the findspot. This hoard had been buried in the virgin soil and deliberately concealed under a residential floor in the Late Bronze Age. The objects recovered served different purposes; they include agricultural and household implements, tools, ceremonial objects and a variety of weapons. The artifacts were all located next to each other in a pit and had been arranged in a regular manner. There were also three shields among these objects. They had been placed next to each other under basins with gutter-shaped pipes and on top of daggers, hatchets, axes, two-pronged forks, and stone rods. These weapons had evidently been positioned at close to the domestic objects. The shields are of strikingly similar shapes, but they differ slightly in the number of openings and bars. Up to now, no similar shields have been found at any other archaeological site. These shields seem to be the oldest shields excavated in Iran. XRD and XRF analyses revealed that one of the shields and other objects of the hoard were made of cast copper-alloy, and they were subjected to cold forging/hammering later.

Increasing population and construction of tall buildings have multiplied the presence of environmental pollutants in cities. On the other hand, people use open urban environments more than before to meet their living needs. In this regard, various factors such as the layout of buildings and the presence of continuous wind currents can play a significant role in the distribution of pollutant particles. The present study was conducted to determine the effect of the layout of high-rise residential buildings on the distribution of pollutant particles by recognizing the air flow in Tehran.

In this research, using descriptive-analytical and comparative methods, using simulation technique using ENVI-met software, wind behavior around the distribution of pollutants has been investigated and analyzed. The method of data collection has been done through library studies and field survey.

According to the modeling of the two different types of layout of selected urban block (Sobhan residential complex in Gheytariyeh district, Tehran)with similar building form–one as the existing situation and the other as the proposed model with orderly layout, the findings demonstrate that the layout alternation of residential blocks affects the natural airflow and wind speed between blocks and an improper and non-methodical locating of high-rise buildings causes a change in natural wind pattern and consequently, leads to secondary effects resulted from intensification or stagnation of wind and thus, influences the dispersion of pollutant particles.

In this research, the obtained results from the two models of buildings layout in the software and the output related to the intensity of wind and the retention level of CO show that the existing situation model is more desirable compared to the proposed layout due to more unified and higher wind speed throughout the site and also proper air circulation between blocks which causes the dispersion of pollution and prevents the retention of pollutant particles.

Perforated thin-walled tubes have always been the focus of researchers as an appropriate energy absorption alternative. In this research, the energy absorption capability of perforated thin-walled tubes with irregular pattern has been compared with thin-walled tubes without holes and regular holes. In this regard, cylindrical thin-walled tubes made of aluminum alloy 6061 have been used under axial loading. At first, the process was modeled using the finite element simulation, and the accuracy of the numerical results was verified using the experimental results. Then, using Taguchi's L16 orthogonal array, the effect of geometrical parameters on the energy-to-weight ratio of the perforated thin-walled tubes with irregular pattern was investigated. Afterward, the optimal arrangement was obtained to achieve the maximum energy-to-weight ratio using the signal-to-noise analysis. Finally, experimental tests were carried out on the tube with the optimal arrangement, the tube without holes and the tube with regular holes. By comparing the energy absorption ability of various tubes, it was found that with the optimal arrangement, the energy-to-weight ratio increases by 19 and 26%, respectively, compared to the non-perforated and regular perforated tubes. Also, using the new proposed pattern, the initial force to average force is reduced by 17 and 19%, respectively, compared to the non-perforated and regular perforated samples.

In this paper, the effects of mooring lines configurations on the dynamic response on truss spar of Kikeh oil field off the coast of Malaysia near the Saba, was investigated. At first, the Aqwa code results were validated. Its results was then compared with Morison equation based DATspar code The RAO results showed that Aqwa software considering diffraction theory gives better results than DATspar code. It means that neglecting the diffraction phenomena leads to unrealistic results and modeling performed in this study is more accurate than previous work. The platform movements in three degrees of freedom in three different layouts of a four-line mooring, including the angles of 0, 22.5 and 45 degrees, respect to wave direction was investigated. The results showed that the effects of mooring configurations on the motions in regular waves in small and large amplitudes are insignificant and considerable respectively. Generally, by increasing the mooring line angle, the response amplitude is increased. For irregular waves, by increasing the mooring line angle from 0 to 22.5 and then from 22.5 to 45 relative to wave, the mean response amplitude of spar initially decreases and then increases. Nevertheless the minimum response amplitude occurs in 22.5 degrees.

Extended Abstract (Paper pages 201-224) Introduction Soil nails are traditionally designed with uniform length and equal spacing to stabilize slopes which do not meet safety requirements. However, nails with uniform layout in a slope may not be the optimal design if the construction cost is taken into account. The optimal layouts lead to a minimum usage of nails and satisfies the allowable factor of safety and wall deformation. In this study a decreasing trend of nails length along the wall height was considered to investigate the stability and the performance of the wall in different nail patterns. Then nail density was introduced as an important factor on the overall stability and deformation of the wall. It can be beneficial in the preliminary estimation of the required nail length at the beginning of a project. Findings of this study are helpful for effective design of soil–nailed slopes. Materials and Methods The finite element analyses were conducted to investigate the effects of nails pattern on the overall stability and deformation of soil–nailed walls. Slope/W software was used to obtain the Factor of safety and Plaxis 2D was used to calculate the deformation of the soil nail walls. Soil hardening model was used to simulate the behavior of soil. In this study, various walls with different specifications were modeled and analyzed. As an example, a 10 m deep soil nail wall with C=10 kN/m2, ?=25 deg, Eoed=20000 kN/m2 is discussed here to monitor the trends (C represents cohesion, ? is the angle of friction and Eoed is the modulus of elasticity of the soil). As it is shown in Figure 1, by considering the decreasing trend of nail length along the wall height, an ordered arrangement (pattern) is introduced by presenting “L” as the base nail length and “” as the inclination of stabilized zone border then, the effect of nail arrangement on the safety factor and deformation of nailed wall is investigated. The nails were installed with an angle of 15 degrees relative to the horizon. According to FHWA a minimum value of 1.35 is considered for the factor of safety. Circular failure surfaces are assumed and the tensile and pullout resistance of the nails crossing the failure surfaces are considered as the governing stabilizing forces. Results and discussion In this study, soil nails pattern effects on the performance and the stability of the soil nail wall are investigated. In Figure 2 variation of safety factors caused by different soil nails arrangements is illustrated. Generally three separated trends are observed in each curve. It demonstrates that at lower values of  with small bond length, the factor of safety is constant. As  increases the bond length behind the slip surface becomes longer and the safety factor is increases gradually. Eventually it reaches a point that the nails are long enough that increasing the nails length is not influential in the stability of the wall. Hence, nails at different elevations of a slope have different contribution to the overall stability of soil–nailed slopes. Wall deformations need to be controlled by the allowable deformation level in designing the soil nailed wall especially when buildings or other underground facilities exist near the excavation. One of the most important parameters on soil nailed wall deformations is the arrangement of nail lengths. Figure 3 shows the effect of nail arrangements on the wall horizontal deflection. In general, as and L increase, horizontal deflection of the wall decreases. The rate of this reduction is higher in lower base length. As it is illustrated in Figure 3, by increasing the length of the nails, the deflection is decreased till no significant reduction is observed. As it is shown the arrangement and the layout of the nails are influential on the stability and deformation of the soil nailed walls. However, it is important to identify an optimal layout in a way that with optimum nail length, allowable stability is reached and the wall deformation stay in an allowable range. Nail density is defined as the ratio of the required nail length per the unit area of the wall surface and defined as below: D_n=(∑_(i=1)^n▒L_i )/A (1) where Li is nail length of each row and A is the stabilization area. Hence, estimating the nail density can be beneficial for the engineers to have a preliminary estimation of the costs of the project at beginning of the project. Figure 4 indicates that the nail density governs the wall deformation. As it is seen, for different layouts with the same nail density, the resulted deflections are so close. Hence, it can be concluded that nail density is a key factor in determination of the wall deflection. It is also illustrated that, as the nail density increases, the reduction rate of the deflection is decreased. Effective nail density is defined as a threshold point that increasing the nail density is no longer effective on deformations. As it is demonstrated in Figure 5, different layouts with a similar nail density have close values of safety factors. In walls with higher nail density increasing the nail length is fruitless and at lower nail density nails are not effective. So Optimum designation should be somewhere at the middle part with an allowable factor of safety. In the middle part the variation of factors of safety is more tangible. Horizontal deflection profile During the construction process the wall tends to move outward. Figure 6 illustrates the effect of soil nails arrangements on the deformation of a 10 m deep wall for a constant base length. As it is shown, by increasing  the horizontal deflection at the top of the wall decreases in a way that at higher  values, the wall deformation mode changes from overturning mode to bulging mode. Conclusion In this paper the effects of soil nail arrangement on the stability and performance of the wall was investigated. An ordered arrangement of the nails was introduced and the effect of various nail lengths at different elevations of the wall was discussed. Major findings concluded from this research are summarized as follows: Nail density was defined as a key parameter and the findings demonstrate that nail density plays an important role in controlling the stability and the performance of the soil nail walls, in a way that patterns with the same nail densities but different arrangements, result in the almost similar factors of safety and deformations. Therefore based on the allowable factor of safety and deformation, nail density can be concluded and the nail arrangement which meets the standards, is selected. Threshold nail density is defined as a value of nail density which no significant reduction of deflection happens afterward. Uniform distribution of the nails and lower values of  generates the maximum deflection at the top of the wall. As  increases, the bond length in the upper parts of the wall controls the deformation. In that case, the deflection value is bounded and the maximum deflection occurs at the middle depth of the wall. Therefore the mode of deformation changes from overturning mode to bulging mode. As a result, in the projects which their adjacent structures are of high importance, it is recommended to use more nail.

in this article, three-dimensional numerical simulation of the steady flow of a Newtonian fluid parallel to a tube assembly with regular triangular arrangements, square and hexagon, which are infinite and there are no walls around them, have been discussed. Fluid flow equations have been solved using SIMPLE method and second-order upwind approximation by Fluent software. The solution process is that first, a uniform velocity distribution is considered on the inlet face around of tubes, and with the movement of the fluid in the parallel direction of the tubes, the flow reaches the developed state. Hydrodynamic inlet length, pressure drop, friction coefficient factor and velocity distribution were investigated according to the ratio of the distance between the centers of the tubes on the diameter. To ensure the accuracy of the simulation performance, the results of the developed part of this research have been compared with the results of valid references. The results show that the length of the hydrodynamic inlet in all arrangements is less than the length of the flow inlet inside a normal circular tube with an equivalent hydraulic diameter and the ratio of this length to the equivalent hydraulic diameter decreases with the increase of the distance between the tubes. Also, by increasing the compactivity of the tubes, or in other words, reducing the distance between the tubes, the pressure drops in the 30-degree arrangement is higher than in the 45 and 60-degree situations.

Hydraulic jump is one of the important phenomena in hydraulic science and it is classified among fast variable flows. This phenomenon enables the consumption of excess water energy downstream of hydraulic structures such as overflows, rapids, and valves. In general, hydraulic jump has a characteristic in which the excess kinetic energy of the flow is lost. This important feature is used as an energy absorber downstream of overflows, valves, rapids, etc. Due to the importance of hydraulic jump in the last seventy years, it has been widely studied and comprehensive information has been published. The aim of these studies was to better understand the jumping mechanism and create relationships to predict its characteristics such as the length of the jump, the depth of the required footing, the amount of energy consumption, the distribution of the flow velocity, pressure fluctuations and the profile of the water level during the jump. Accurate estimation of these characteristics has helped to design more economical and safer energy consuming structures.

In this research, the hydraulic jump in the compound channel with floor roughness has been investigated using Flow 3D software. In this simulation, the composite cross-section is rectangular-rectangular with a length of 12 m, which consists of two sections, the main channel and the floodplain. The depth and width of the main channel are considered constant. The simulations are performed in two width ratios (wr), four relative depths (Dr) and three different roughness height ratios (nr). All simulations are performed at three different speeds. The arrangement of floor roughness is regular. The roughness of the floor is in the form of small cubes, which are located at a distance of 1 meter from the beginning of the channel. The depth and width of the roughness of the bottom of the main channel and flood plains are 6 cm. The height of the roughness of the bottom of the main channel is considered to be 3 cm, but the height of the roughness of the flood plains is 3, 6 and 9 cm according to the defined proportions. The distance between each roughness on the bottom of the main channel is 3 cm and the distance between each roughness on the bottom of the flood plains is 2 cm. The distance between each roughness group is 0.15 meters. Boundary conditions were applied on 6 cubic faces of the solution grid. The boundary conditions used in the simulation are such that the upstream boundary is in the form of flow velocity, the downstream boundary is in the form of outlet, the ymin side wall boundary is in the form of a wall (right floodplain), the ymax side wall boundary is in the form of a wall (left floodplain). the border of the side wall of the main channel was chosen symmetrically, the border at the bottom of the main channel and floodplains was chosen as a wall, and the border at the water level was chosen symmetrically.

According to the results of the simulations, the presence of roughness has reduced the secondary depth of the jump compared to the case without roughness. So that in Silabdasht width of 18 cm and depth ratio of 0.3, roughness height ratio of 2 and speed of 3.5 m/s, the average secondary depth is reduced by 5.64% compared to the channel without roughness. But the increase in the width of the floodplain caused a decrease in the secondary depth of the jump by about 26.26%. The lowest value of the secondary to primary depth ratio of the jump can be seen in the relative depth of 0.7 and the roughness height ratio of 2. It was also observed that with the increase in the ratio of the height of the roughness, the length of the jump decreases significantly in small depth ratios. The length of the jump is reduced by about 10.98% in the lowest value of the roughness height ratio, the width of the flood plain is 18 cm, the speed is 5.3 m/s and the depth ratio is 0.3, and it is reduced by about 47.37% in the highest value of the roughness height ratio, the speed is 5 m/s and the depth ratio is 0.3 find Also, with the increase in the width of the floodplain, the jump length decreases in a constant roughness height ratio.

Nowadays, soil nailing is a common method of excavation stabilization which its design is based on the arrangement of nails along the wall height. Nail arrangement is typically selected by a trial and error approach among different arrangements which satisfy allowable stability safety factor and allowable deformation. In This Study, by considering the decreasing trend of nail length along the wall height, an ordered arrangement is introduced by presenting “L” as base nail length and “” as inclination of stabilized zone border and the effect of nail arrangement on safety factor and deformation of nailed wall is investigated. Also, by introducing nail density per unit area of wall surface (Dn), its effects on soil nail wall behavior is studied in each arrangement. The results show that by increasing L and safety factor increases and wall top deformation decreases. It’s also recognized that safety factor and deformation values, apart from arrangement parameters, are Proportionate and corresponding to the nail density key parameter. It was also found that with an increase in nail density, safety factor increases and deformation decreases but these trends will decline in a specific nail density which is called the effective nail density. By investigating wall deformation mode in different arrangements, it was found that when  is small, maximum wall deformation occurs in its top and the deformation mode is overturning, while by increasing  and enhancing upper nail lengths, maximum deformation of wall transfers to mid depth of the wall and the deformation mode changes to bulging.

In this study, a particle-based model incorporating all inter-particle interactions was employed to simulate the electrophoretic deposition process. This model was also used to investigate the effect of the surface (zeta) potential of particles on the structure and configuration of particles in the deposited layer at the mesoscale. Simulations were then performed with four different values of zeta potential of particles {-5, -25, -50, -100} mV, the results of which showed that zeta potential as an important factor in determining the interaction between particles had an impact on the deposit structure and packing. Upon increasing the zeta potential up to 50 mV, the degree of order increased while the thickness and density of the deposited layer slightly decreased. Increasing the electrostatic repulsion made depositing particles push into the ordered sites in the deposited layer. Due to the high particle repulsion that prevents particles from approaching each other at the zeta potential of 100 mV, incorporation of the particles in the ordered locations decreased again. The findings of this study along with application of the proposed model can help tune the structure and packing of the resulting deposit by varying the zeta potential of particles.