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154 Abstract Numerical Analysis of Ground Reinforced with a Stone Column Group Saeedeh Tabarsaz and Abbas Soroush School of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran soroush@aut.ac.ir Abstract This paper presents the numerical analyses of a group of stone columns penetrated in a 10 m deep soft clay stratum. A rigid raft transfers the super-structure's loading to the stone columns and the parent ground. The columns group comprises of five columns with a symmetric configuration. The numerical analyses are performed on a plane strain idealization of the structure, using an elasto plastic constitutive behavior for both the stone columns and the soft clay layer. Additional numerical analyses with different range of parameter, like number of columns, space of columns, column’s length, foundation’s size, Poison ratio of soil and stone columns’ material and modulus of elasticity ratio of the stone columns’ material were conducted. The results of analyses showed that lateral displacements (bulging) occur in the upper parts of the columns (between 2D and 4D from the top; D is the column diameter) and the lateral displacements are comparatively higher for the side columns. The major result of the analyses is that for a group of stone columns supporting a rigid raft under spread loading, the lengths of the stone columns could be designed unequal, i.e., inside the columns can be shorter, without significantly increasing of the settlements of the column group.

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Holding companies differ in nature from commercial companies. Adopting a specific policy towards products and services, holding companies support and control their subsidiaries. Competition and strategic planning conceptually differ in companies and ordinary commercial companies owing to the fact that no two holding companies, which provide similar products and services can be found, even at the international level. Information systems strategic planning (ISSP) is accomplished to develop an orientation toward the investment in information and communications technologies that aligns with the strategic objectives of the organization. As mentioned earlier, due to the differences between parent companies and ordinary commercial companies with single- or multi-products/services in terms of strategic planning and competition, the information systems strategic planning process in holding companies follows quite different steps. This distinguishing nature leads us to take considerations into account in ISSP steps. Applying balanced scoredcard method, this article concentrates the limited resources of investment on the processes that fulfill an essential role in accomplishing the strategic objectives of holding companies.

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Objective: Sea cucumber is a traditional food and medical item and has been reported to exhibit Antioxidant, antifungal, anti tumoral and antibacterial bioactivity. The objective of this study is to describe the antibacterial activity of 4 extracts of Holoturia. Sp (sea cucumber), collected from Hengam Island of Persian Gulf. Materials and Methods: Methanol, hexane, aqueous and chloroform extracts from body wall tissue of the sea cucumber were screened for antibacterial activity against three strains of Escherichia coli Top 10 F´, TG1 and K12 using disc diffusion and broth microdilution tests methods. Result: The growth of all these strains were inhibited using concentration from 0.78 to 100 mg/ml of methanol, hexan and chloroform extracts. Among the extracts just methanol and chloroform with 100 mg/ml had bactericidal effect on TG1 and K12 strains. On the other hand, Aqueous extract had induced growth in of the all strains. Conclusion: The results suggest the possibility of applying sea cucumber as source of potential anti bacterial agents, whose compounds can be good candidates to make antibiotic products.

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Abstract: Some of the structures founded on clay soils in the desert area of the country, especially in Yazd, have suffered damages, most probably due to swelling of the soil. The ambiguity in the interpretation of the mechanisms and causes of these damages has necessitated studying swelling characteristics of these soils. Thirty soil samples, taken from 1.5m to 3.0m below the ground surface, were tested.  Tests included: (a) physical tests including determination of Atterberg Limits, hydrometer method gradation, natural dry density, water content, and swelling pressure/percentage; (b) chemical tests for determining chemical substances and cations of the samples and (c) XRD tests to determine the soil mineralogy. According to the indirect methods of swelling assessment, most of the samples lie in the medium to low swelling potential catgories. The direct oedometer test support this notion. The prevailing minerals present in the soil samples are illite and calcium montmorillonite. The paper also presents the relationships between the swelling potential and the Atterberg Limits, clay fraction, sodium and calcium contents of the soil.

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Using adaptive minimum variance beamforming (MV) results in a significant improvement in image resolution, but it’s success in enhancing contrast has not yet been satisfactory. In some researches, eigenspace-based minimum variance beamforming (EIBMV) method has been applied to medical ultrasound imaging system, so that it has improved image contrast while maintaining its resolution. In this paper we apply another eigenspace-based beamforming called eigencanceler (EC) and show it can yield more satisfactory results. However EC needs the noise – interference covariance matrix, whereas the MV and EIBMV use the data covariance matrix. So an altered EC is proposed for the ultrasound imaging. In this method, while canceling the desired signal does not occur, any weight vector is considered to lie in the noise subspace, the subspace orthogonal to the dominant eigenvectors. Otherwise, the weight vector is defined uniformly. Simulation results show the superiority of this method over the MV and EIBMV methods in the contrast aspect. Moreover, the method is more robust against the sound speed errors and can obtain images with better definition of boundaries.    

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The main problems in machining of thin-walled parts made of high-strength aluminum alloys are distortion and dimensional instability, which lead to an increase in distorted part scraps and production costs. This article attempts to investigate the correlation between machining-induced and quench-induced residual stresses and the distortion of thin-walled parts made of AL7075 alloy. The experiments are carried out in two steps. In the first step, the effects of polymer and uphill quenching methods in comparison with water quenching in the reduction of residual stresses are investigated on an experimental basis. By conducting the machining tests, the effect of residual stress on distortion is investigated. In the second step, several experiments are carried out under different machining conditions. To study the effect of mechanical and thermal loads on the residual stresses and distortion, the machining force and temperature of cutting area are measured. Finally, the correlation between the machining-induced residual stress and distortion is studied by measurement of stress on some parts. The results indicate that both machining and quench-induced residual stresses are effective in distortion of thin walled parts.

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In this paper, simultaneous impact of two parallel drops on a thin liquid film is investigated using the lattice Boltzmann method. The purpose of this study is to investigate the effects of surface tension (characterized by Weber number), distance between two drops, and gas kinematic viscosity on the impact. The developed numerical model in this paper which is based on the Shan and Chen pseudo-potential two-phase model makes it possible to access large density ratios, low viscosities, and tunable values of surface tension independent of the density ratio. The model is validated by comparing the coexistence densities with those of Maxwell analytical solution, evaluating the Laplace law for a droplet, and simulating single droplet impact on a thin liquid film. Simulation results of two drops simultaneous impact show that after impact, two jets raised between the drops join each other and form a central jet. Height of this jet increases with time leading to separation of secondary droplets from its tip. When the surface tension value is decreased, the central jet height is increased, but size of the separated droplets is reduced. The crown shape observed in single drop impact is also seen in simultaneous impact of two drops. Increasing distance between two drops leads to a smaller central jet height and an increase in the crown radius. The crown height, however, was found to be independent of the distance. Finally, increasing gas kinematic viscosity reduces the central jet rising speed and delays separation of secondary droplets from the jet.

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In this study a numerical model based on the finite element method is used to simulate the behavior of human lumber spine. Due to lack of realistic models, in the present work a lumber spine model is generated from Computational tomography (CT-Scan) images by Mimics 17 software. Also, according to the wide range of loading conditions, to achieve realistic results, optimized loads acquired from other researches are used. Human lumber spine model which is used in this study consists of five vertebrae, five discs, and all ligaments. Model is loaded under statically conditions and calculated with ANSYS-Abaqus 16 (Simulia Inc., Providence, USA) software. Obtained results are compared with other numerical simulation results and experimental measurements which are reported in other researches. Numerical modeling consists of six cases as follows: intervertebral rotation, interadiscal pressure and facet joint forces under the axial rotation and lateral bending with compressive follower force loadings. In all cases, intervertebral rotation, interadiscal pressure and facet joint forces are reported. Comparisons show that obtained results have a good agreement with experimental measurements. Therefore, results show that realistic model with optimized loadings predicted the behavior of lumber spine more accurate than other numerical models.

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In this study, the hydrostatic vibration analysis of an isotropic rectangular microplate in partial contact with a bounded fluid is studied. Modified couple stress theory based on the Kirchhoff plate assumptions are used to mathematically model the problem. The extended Hamilton’s principle is employed to drive the governing differential equation of motion and the corresponding boundary conditions. The transverse displacement of the microplate is approximated by a set of admissible functions which must satisfy the geometric boundary conditions. The fluid is assumed to be incompressible, inviscid and irrotational and the fluid velocity potential is obtained using the boundary and compatibility conditions. Natural frequencies of the microplate are calculated using the Rayleigh-Ritz method. To validate the present results, the natural frequencies of an isotropic macroplate in contact with fluid are compared with the available data in the literature and very good agreements are observed. Finally using the numerical data, the effect of different parameters such as thickness to length scale parameter, aspect ratio, length to thickness ratio and boundary conditions on the natural frequencies of the microplate are discussed in detail. We have observed that the difference between the natural frequencies predicted using the classical theory and the one evaluated by the modified couple stress theory is significant when thickness of the microplate is small, but diminishes as thickness increases.

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In this paper, a new method is proposed to reach high density ratios and low viscosities based on the Shan-Chen multiphase model in the lattice Boltzmann Method. In this new method the interaction force and as a result the pressure tensor is modified purposefully so that the density of the phases can be adjusted to coincide the corresponding values from the Maxwell equal area rule in thermodynamics. This leads to higher stability and therefore the mentioned purposes are achieved. This new method takes advantage of simplicity and the same implementing procedure in 2D and 3D problems with single or multi relaxation time collision operators. In order to validate the new method, first the coexistence densities of the phases at different subcritical temperatures are compared with those of the Maxwell rule, then the validity of the Laplace law for a droplet is evaluated, after that the spurious velocities around the droplet are evaluated, and finally the broken dam problem is simulated and its results are compared with an experimental data. Results show that the developed model is properly stable and is capable of simulating different multiphase flows at a wide range of density ratios and viscosities.

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The robot has to adapt its movement with the various condition of surfaces and ensuring the stability with the proper motion of its bust and legs in order to be able to move on different surfaces. A lot of basic parameters of the gait can be expressed by the planned seven-linked bipedal robot. One of the issues that have always attracted the attention of researchers, in this field, is to predict the motion path that guarantees the stability and minimizes the energy. In this study, parameter optimization being used which means that at the first, joint angles are defined as a parameter functions and then with respect to kinematics constraints that define maximum and minimum of joint angles, the problem of motion obtained in the way that maximizing stability of robot and minimizing energy and puts the robot in the permitted stable region. Also, we tried to have zero moment point scale used to calculate the stability of robot. Experimental tests in order to motion analysis for walking healthy were performed and the results were validated. Finally, due to the presented model and predicted path, the robot can move like a person. Comparison of experimental results and the result of presented model were used in each step to validate the accuracy of the proposed method.

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Due to progressive consumption of fried food products in the country, increase of quality and oil uptake reduction of them is necessary. Acrylamide as a potent human toxicant is present in different heated food products, with unexpectedly high levels in potato products such as french fries. Prevention of acrylamide formation in food could minimize its dietary exposure and therefore decrease its potential health risks to humans. For this purpose, blanched potato slices were immersed in curcumin extracts (0, 5 and 10% w/w) for 15 minutes, followed by friying in oil. Water content, oil uptake, shrinkage, color (L*, a*, b*), acrylamide content and sensory properties were analysed. The results showed that increasing curcumin concentration increased the water content and decreased the oil uptake and shrinkage in all samples. Color parameters indicated that by increasing curcumin extract concentrations, L* and a*of the potatoes decreased, but b* was increased. The immersion in a solution of curcumin extract reduced the content of acrylamide in french fries significantly. As increasing concentration of curcumin up to 10% the amount of acrylamide decreased in 47% compared to control sample. Sensory characteristics (appearance, smell, taste) with the exception of flavor at a concentration of 10% curcumin extract improved with increasing extract concentration. Useing of curcumin extract, along with improving the quality and sensory properties, led to a significant reduction in acrylamide formation in fried potatoes and could be suggested as a method to reduce the formation of this toxic compound.

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Lipid oxidation is important issues that can lead to the degradation and destruction of foods containing lipids. A number of antioxidants have been used to solve this problem. Stachys lavandulifolia is a medicinal herb with antioxidant properties. Given that the impact of new technologies compared to traditional methods in terms of saving time, energy, and increase the efficiency of extraction have been identified. The aim of this study was modeling the extraction of antioxidant compounds from Stachys lavandulifolia by ultrasound-assisted extraction method. For this purpose, to model the extraction efficiency of neural network antioxidant compounds, artificial neural network hybrids - genetic algorithm and response surface methodology were used. The best model was obtained based on the results of the neural network model with gradient optimization method, with trainbr training and tansig transfer function and the number of hidden layers of this combination with two neurons 8 in the first layer and 4 in the second layer. For this network structure, an error of 0.0128 and a correlation coefficient of 97.30% were determined. By comparing this method with the response level, the model accuracy increased from 92% to 94.68%. The best result for the hybrid model occurred in the trainbr learning algorithm with the tansig transfer function with a hidden layer and 18 neurons. The error rate and correlation coefficient in this method were equal to 0.0693 and 83.27%, respectively. According to the results of the neural network with the logger method, it answered better and the hybrid method of the genetic algorithm with the neural network was not a suitable model for prediction. Finally, it can be said that mountain tea can be considered as a potential source of antioxidant compounds and neural network can be considered as a successful application method to predict the extraction efficiency of antioxidant compounds.

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In the past two decades, explaining the technology strategy as one of the most crucial needs of various entities was particularly considered and many experts in the field classified it at a higher level than other operating strategies in terms of its profound influence on other operating firm operational strategies. The aim of developing technology strategy in an organization is the method of achieving competitive advantage position and how to realize the long-term technological goals. In this study in order to formulate technology strategy in the steel industry after reviewing the conducted studies a model was presented based on the strategy map and the identification of key processes. First, the key processes were identified according to the company's strategic goals. Then, the key process technologies with process approach were identified through the interview with senior managers and the study of electronic sources. Finally, in order to evaluate the identified technologies, the matrix of technology feasibility/attractiveness was used. By putting the technologies in the matrix, 7 technologies were placed in the area of high feasibility and attractiveness, 1 technology in the area of low feasibility and attractiveness, 4 technologies in the area of moderate feasibility and attractiveness, and 2 technologies in the area of high feasibility and moderate attractiveness. For each area an appropriate strategy was proposed.