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The rule "There is No Effect on the Existence Except Allah" is emphasized by the Ash'arites and Mulla Sadra. But each has offered a different interpretation of this rule; According to this rule, the Ash'arites have denied any causation, influence, or effect among the possibilities, and attribute all actions exclusively and directly to God Almighty. But Mulla Sadra, based on his philosophical principles in transcendent wisdom, while proving the near activity of God for all actions, also accepts a role for other possibilities in actions and proves a kind of influence and effect among the obligatory sub-transcendence. In this article, with a descriptive-analytical-critical method, both views in this regard were examined. Accordingly, neither view is flawed. Of course, Mulla Sadra's view, with the explanation given by Mullah Ali Modarres, is largely free from problems.
 

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The present study aimed to analyze affecting factors on agricultural experts moving toward becoming agricultural e-marketing users. During a correlation-descriptive research method, variables of the study were prioritized through Theory of Planned Behavior (TPB) and correlation between variables and adoption was computed and finally the most effective variables on adoption were determined using logistic regression. Results showed that behavioral belief (Attitude), normative belief (Subjective norm) and control belief (Perceived Behavioral Control) were affecting adoption. Among personal abilities and skills, engagement in agricultural jobs had the greatest effect on adoption which was related to control belief of the respondents. positive belief toward e-marketing and believing that had next great effect on decreasing traditional interferences respectively and variables related to behavioral belief had more important role in forming attitude of experts. Finally, agricultural companies were the most affecting variables on subjective norm of experts among other affecting components of agricultural market included in normative belief. Respondents selected network of agricultural advisory service companies which had an interference role between producers and customers as a proper option in e-marketing for local farmers. In this case, companies could merely deal with providing information of farmers’ products to suppliants through internet websites without playing direct role in buying and selling.     

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The most important application of explosive welding in cylindrical geometry is cladding of cylindrical surfaces in order to increase corrosion and wear resistance and also improving the mechanical properties of bimetal product. In this study, the explosive welding of bimetal tubes made of steel and Phosphor-Bronze was investigated using two explosives (TNT and Amatol 5-95) with different explosion velocity. At first the explosive window of two metals was achieved using the theoretical-experimental relations, and then using different experiments, the key role of explosion velocity and also the position of selected parameters of explosive window in the metals weldability were determined. At the end, the successfull method of manufacturing of this bimetal tubes is presented and commented upon.

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Aims: This research aimed to study the effect of virtual social networks on self-care of the users concerning COVID-19.
Instrument & Methods: This survey research was conducted from April to June 2020. The study sample included social network users (WhatsApp, Instagram and Telegram) in Hormozgan province who were selected by convenience sampling. The measuring instrument was an online questionnaire extracted from Dorthea E. Orem’s self-care model, Gerbner's cultivation theory and Kaplan and Haenlein's media-richness-theory. Modeling was carried out using SPSS 28 and Amos 26 software.
Findings: The results of explanation and modeling in the present research not only indicate a significant and direct relationship between the independent variables of Presence and interaction in the social networks and user orientation to the type of social network with the dependent variable of users concerning COVID-19 self-care (p<0.0009), but also, 45% of changes in COVID-19 self-care variable was covered by a set of social networking indices. Structural equation modelling in the self-care variable also showed that independent variables; Presence and interaction in the social networks and user orientation to the type of social network had the highest and lowest effects on the psychological support dimension with a standard coefficient of 0.99 and the dimension of awareness and attention to COVID-19 effects and outcomes with a standard coefficient of 0.95, respectively.
Conclusions: As a result, we suggest that health officials and disease control and prevention centers use the potential of social networks such as WhatsApp and Instagram in self-care of users concerning COVID-19.

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Abstract: Applications of two-phase flow in nuclear power plants, transmission lines, oil and gas have been considered in recent decades. Different models have been introduced that can contribute to the current two-phase flow approach to numerical analysis. Two-fluid model is the most widely used and most accurate model for predicting two-phase flow in channels during different regimes of unstable flow. This study addressed the PFM model Hyperbolicity. Hyperbolicity of this model is the most important for the well-posed condition; otherwise the model is in ill-posed condition and the results are unstable numerically. Hydrodynamic instability of two-phase gas-liquid by using the PFM model is calculated and discussed.

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In this article, for the first time the numerical solution of Godunov method with HLLC Riemann solver is extended for a hyperbolic five equations two-fluid model. The flow field is considered for two-space dimensional case. So far, two main difficulties include non-monotonic behavior of mixture sound relation and inability of shock transition from interface was mentioned during working with this model. In this research these difficulties were overcome by selecting an appropriate mixture sound relation and appropriate discretization of non-conservative term. The mutual effect of shock wave impact with a droplet and two droplets with different diameters were simulated and studied. During the shock wave impact with 1.47 and 6 Mach with the droplet, a complicated shape of interface was formed with high pressure zone and low pressure zone of cavitations. The results obtained from the present attempt were compared with the experimental and related similar results of that obtained by the other numerical methods and models. The comparison of the results was good. It was also concluded that the numerical method used in the present work has enough accuracy with high capability in capturing two-phase flow interfacial instability and shock wave impact transmission from the droplet.

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Studying of connection between a carbon nanotube (CNT) and its surrounding matrix is an important issue in investigation of the behavior of nanocomposites reinforced with carbon nanotubes. In this paper, the carbon nanotube and its surrounding matrix is considered as a volume element and its mechanical behavior is analyzed using finite element method. Interface joints are modeled utilizing nonlinear spring elements; and effective force between CNT and matrix is determined based on Lennard-Jones equation. The interface thickness is changed between 1.7-3.8Am, to study its effect on the volume element behavior. Tensile loading of volume element is applied in two ways to investigate the perfect connection between nanotube and matrix. Subsequently, tensile longitudinal elastic modulus of volume elements with different aspect ratios of nanotube and thickness of interface are calculated and compared with the results of rule of mixture theory in micro mechanics field. The results of this research indicate that for low aspect ratios, the amount of elastic modulus is near to individual resin or nanotube. But, increasing the aspect ratio causes the connections to be more efficient and results converge to rule of mixture

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In this paper, a unit cell based micromechanical model is presented to predict the elastic-viscoplastic response of aligned short fiber titanium matrix composites subjected to combined axial loading in the presence of fiber/matrix interfacial damage. The effects of manufacturing process thermal Residual Stress (RS) are also included in the analysis. The representative volume element (RVE) of the short fiber composites consists of c×r×h cells in three dimensions in which a quarter of the short fiber is surrounded by matrix sub-cells. In order to obtain elastic-viscoplastic curves, the fiber is assumed to be linear elastic, while the matrix exhibits elastic-viscoplastic behavior. The Evolving Compliance Interface (ECI) model is employed to analysis interface damage. This model allows debonding to progress via unloading of interfacial stresses even as global loading of the composite continues. Results revealed that for more realistic predictions, in comparison with available experimental and the other models results, both interfacial damage and thermal residual stress effects should be considered in the analysis.

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Marine transportation is the most conventional method for transportation of natural gas, mostly liquid form; namely, Liquefied Natural Gas (LNG) to international far market. Hereon provide safe transportation of natural gas is very important. In the event of exterior material contact to LNG, swift boiling and exploding anticipated. The paper, investigates thermo physical water contact (0oC as a fluid with higher temperature) with liquid methane (cause the similarity of thermo physical properties to LNG) at low temperature (-162oC). The intensity of heat transfer between water particle and liquefied methane resulted to swift pressure increase in vapor film. It causes the generation and swift growth of methane vapor film which has been resulted from abrupt evaporation and results to liquid methane explosion. In this situation, the intense vapor explosion phenomena, endangers the safety of system. Mathematical model of these phenomena has been developed by assuming saturation condition on interface phase. Then, the effects of different thermo physical parameter changes on vapor film growth have been investigated. Based on the results, in some cases, the vapor pressure pulse created in the film has been more than 3 times the initial pressure, which can endanger the safety of system.

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The cone-penetration test (CPT) is a well-established in situ test in geotechnical engineering for soil classification and estimation of soil properties. In a CPT, a cone shaped penetrometer is pushed into the ground at a constant rate. The resistance on the cone tip is measured and is then related to soil classification and soil properties. In this research, the finite difference analysis of large deformations for the cone penetration testing (CPT) in the cohesive soil have been conducted using FLAC 2D Software. In this modeling, interface elements between penetrometer and soil are considered and it is assumed that the penetrometer materials show rigid behavior in reaction to the soil materials. FLAC provides interfaces that are characterized by Coulomb sliding and/or tensile separation. Interfaces have the properties of friction, cohesion, dilation, normal and shear stiffness, and tensile strength there is an in-situ state of stress in the ground, before any excavation or construction is started. In FLAC 2D, an attempt is made to reproduce this in-situ state by setting initial conditions. Ideally, information about the initial state comes from field measurements. Boundary conditions are modeled as axesymmetry. Horizontal and vertical direction at the bottom boundary and horizontal direction at the vertical boundary of soil model are fixed. Soil behavior follows full elastic–plastic model and Mohr-Coulomb failure criterion. Numerical model is analyzed to achieve mesh convergency at the various grids. The values of cone and frictional resistance have been obtained through software calculations and then compared with the results obtained from cone penetration test at the aluminum melt factory in Lamard, Fars Province. Stress and displacement contours are related for evaluation of the penetration process. Steady state is considered to achieve steady stress range in which the hole diameter is equal with the CPT hole. The numerical modeling results of CPT test by FLAC 2D software shows good agreement with the field tests results. Furthermore, the results have been discussed by using Robertson Chart 1986 and Eslami- Felonious Chart 1997. Charts almost show same profile with the field test results at the aluminum melt factory site.

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Due to high strength and stiffness in comparison with their weights, laminated composite materials are widely used in many structures such as aerospace and naval structures. Therefore, the understanding of their failure mechanisms to predict their mechanical response is of high importance. One of the major aforementioned mechanisms is the delamination which commonly occurs in skin/stiffener joints. In the present paper, a comparative study on the delamination in composite skin/stringer structures under 3 point and 4 point bending loads is performed by the finite element method (FEM) employing the cohesive elements. The detailed effects of stacking sequence on the damage of structure are investigated. A user defined interface element has been implemented in the Ansys software in continuum damage mechanics framework based on the bilinear cohesive zone model. The advantage of this method is the modeling of delamination growth without any requirements to the presence of initial crack and remeshing. Comparison of the obtained results from FEM with that of experiment justifies the capability of the employed model to predict the delamination initiation and propagation. The results indicate that in the 3 point bending load, the damage initiates from the adhesive between skin and stringer, while in 4 point bending load it initiates from the interface elements between skin layers near the adhesive bond. Finally, in order to increase the strength of skin/stringer structures, the results strongly recommends preventing the use of 45 and 90 degrees plies near each other around the adhesive bond.

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Numerical modeling of compressible two-phase flow is a challenging and important subject in practical cases and research problems. In these problems, mutual effect of shock wave interaction creates a discontinuity in fluid properties and interface of two fluids as a second discontinuity lead to some difficulties in numerical approximations and estimating an accurate interface during hydro-dynamical capturing process. The objective of this research is to increase the accuracy of numerical simulation of two-phase flow using two dimensional five-equation two-fluid model. For this purposes, MUSCL strategy was used for increasing the Godunov numerical scheme accuracy from 1st order to 2nd order. The privilege of this method is high accuracy, low numerical oscillation and low numerical diffusion. The problems considered for the verification of the results are the water-air shock tube, a square bubble with moving interface in a uniform flow and a shock wave with 1.72 Mach having interaction with an air bubble in a water pool. The obtained numerical results showed that, the results that have been obtained by second order accuracy have less diffusion in the two-phase flow interface.

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Explosive welding is used for excellent bonding of similar and dissimilar materials with the wide variety of thicknesses,area dimensions and different thermal and mechanical properties. In this study, an Al/St/Al multilayer sheet was fabricated by explosive welding process and the effects of annealing temperature on the interfacial properties of explosively bonded Al/Cu bimetal have been investigated. For this purpose, hardness changes along the thickness of the samples have been measured, and the thickness and type of intermetallic compounds formed at the joining interface have been explored by means of optical microscopy (OM), scanning electron microscopy (SEM) and also energy dispersive spectroscopy (EDS). By heat treatment of the samples at 300, 350 and 400°C, it was observed that intermetallic layer was formed at the interfaces. The obtained results indicate that, with the increase of the annealing temperature, the thickness of intermetallic compounds has increased and the amount of hardness along the thickness of the joining interface has diminished. In the annealed sample at 300 °C for 60 min, it was observed that intermetallic layers have formed at the interface of Al/St bimetals. These layers consist of the intermetallic compound Al2Fe and its thickness gets to about 35 μm at some points.

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In present work, models that predict contact angle of a droplet with a solid surface, are considered and compared with each other. Two phases were assumed to be Newtonian, incompressible and immiscible fluids. OpenFOAM software is applied to simulate the two phases interface by using Color function VOF (CF-VOF) method. Different models for contact angle of a droplet as Tanner and Yokoi models are implemented in the OpenFOAM. In addition, the dynamics and statics contact angle models were used to compare with recent models in order to choose the best one. The outcome of study shows, even though the static contact angle model is simple to understand, however, it could be the best model to predict the droplet behavior in a wide range of different conditions. The fluid viscosity effect was also considered in different models of the present study. It concluded that the fluid viscosity affects the type of pattern of droplet impact and as viscosity of fluid increases; more energy is needed to uplift the droplet again from the surface. Kelvin-Helmholtz instability (K-H) was also simulated and explained in details which initiates on the interface of two fluids due to velocity differences of droplet and the surrounded air.

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Extended finite element method (X-FEM) has been recently emerged as an approach to implicitly create a discontinuity based on discontinuous partition of unity enrichment (PUM) of the standard finite element approximation spaces. Despite numerous progresses in mesh generating updating of finite element mesh during crack propagation remain extremely heavy and difficult. This problem becomes more complicate, when there are many discontinuities in the finite element domain. However, the extended finite element method (X-FEM) in the combination with level set method (LSM) could overcome this cumbersome issue. In this contribution, predefined cracks and internal boundaries are created using level set functions and also the effects of soft/hard inclusions (interfaces) and voids are considered on crack propagation schemes. In fact, the interaction of crack and heterogeneities are considered. The level set functions are utilized to represent the locations and the evolutions of internal interfaces. In addition, the stress intensity factors for mixed mode crack problems are numerically calculated by using the interaction integral method. Different crack growth paths are simulated automatically for different oriented edge and center cracks and the interactions of internal boundaries on crack propagations are shown. All numerical examples are demonstrated the flexibility and capabilities of X-FEM in the applied fracture mechanics.

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Applications of aluminium and magnesium castings have been increased, as a result of increasing demand for the light weight components in various sectors of industries, in recent years. In this work an Al/Mg bimetal was prepared by casting Al melt into a cylindrical Mg bush, with 35 mm height and 76 and 84 inner and outer inner diameter, rotating at 1200 and 1600 revolutions per minute (rpm), 0.9, 1.6 and 2.7 melt-to-solid volume ratio and 30, 120, 150 and 200 oC preheating temperature, respectively. Vertical centrifugal casting process was selected for producing samples. In this process melt is under effect of centrifugal, coriolis and gravity forces during filling. Difference between shrinkage of Al and Mg led to the formation of mechanical bond in the interface. The results of scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis showed that concentration gradient changes from Mg to Al side in such a way that three sub layers including Al3Mg2 and Al12Mg17 intermetallics plus eutectic microstructure (Al12Mg17 and δ), were formed, based on aluminium and magnesium phase diagram, in the interface

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Using the soft fingers increases stability and dexterity in object grasping and manipulation. This is because of the enlarged contact interface between soft fingers and object. Although slippage phenomenon has a crucial role in robust grasping and stable manipulation, in the most of previous researches in the field of finger manipulation, it is assumed that the slippage between finger and object does not occur. In this paper, slippage dynamic modeling in object grasping and manipulation using soft fingers is studied. Because of the enlarged contact interface between soft fingers and object, a frictional moment along with tangential frictional force and normal force is applied on the contact interface. Therefore, a novel method for dynamic modeling of planar slippage using the concept of Friction Limit Surface is presented. In this method, equality and inequality relations of different states of planar contact is rewritten in the form of a single second-order differential equation with variable coefficients. These coefficients are determined based on the slippage conditions. This kind of dynamic modeling of contact forces can be used for designing the controllers to cancel the undesired slippage. The method is used in study of slippage analysis of a three-link soft finger manipulating a rigid object on a horizontal surface. In order to increase the accuracy of dynamic modeling of soft finger, dynamics of soft tip is integrated with the dynamic of finger linkage. Dynamic behavior of this system is shown in the numerical simulations.

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Due to the influence of Internet and mobile service in every part of our lives in addition to pervasive demand for them, next generation wireless networks should be able to address different kind of objectives or demands. New generation of cellular networks must achieve high user quality of experience (QoE) in order to satisfy the user demands and survive in market. To meet this demands, drastic revision need to be made in previous network architecture. This paper reviews some of the key technologies which are emerged to improve future network architecture and meet the demands of users, especially in Fifth generation (5G) cellular network. In this paper, the prime focus is on the air interface of 5G
which includes millimeter wave communication, multiple access technologies, carrier aggregation (CA), and massive Multiple-Input Multiple-Output (MIMO).

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In electromagnetic motors, increase in output torque leads to increase in rotor inertia. Various robotics applications, especially haptic interfaces, oblige convenient dynamic performances of electromagnetic motors which are strongly in turn influenced by the rotor’s inertia. In the present paper, a robust control method for a viscous hybrid actuator is developed which supplies a desired varying torque while maintaining a constant low inertia. This hybrid actuator includes two dc motors with the shafts coupled through a rotational damper using a viscous non-contact coupler. This coupling method is based on Eddy current to provide the required performances. The large far motor eliminates or reduces the inertial forces and external dynamics effects on the actuator. The small near motor provides the desired output torque. Since the system is essentially linear, the applied robust control method is based on Hꝏ and parametric uncertainties and physical constraints including motors’ voltages saturation, rotary damper’s speed saturation, fastest user’s speed and acceleration applied to the actuator and force sensor noise are considered in its design. Also the robust method of µ-synthesis for the system in presence of parameteric uncertainties and other physical constraints are studied. The implementation of the controller on a 1 dof haptic interface model validate the achievement of the desired performances.

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The elastic behavior of an edge dislocation located inside the core of a core-shell nanowire which is embedded in an infinite matrix is studied within the surface/interface elasticity theory. The corresponding boundary value problem is solved exactly by using complex potential functions and Laurent series expansion. An important parameter so-called interface characteristic parameter which has the dimension of length and is a combination of the interface moduli enters the formulations. The stress field of the dislocation, image force acting on the dislocation, and the dislocation strain energy is calculated by considering the interface effect. The stress field of the dislocation is shown as contour plots and the results are compared with classical case. The image forces acting on the dislocation are studied in details and it is shown that they depend on the interface characteristic parameter, nanowire dimension, dislocation orientation, and dislocation distance from the interface. Moreover, the repelling and attracting effects of the interface parameter on the image force are discussed. The equilibrium position of the dislocation is also studied. The dislocation strain energy in the interface elasticity framework is only slightly different from that of traditional elasticity when the dislocation is placed in the central region of the core and reaches its maximum value when it is located near the core–shell interface.