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For decades, both researchers and EFL learners have been interested in native-like pronunciation. While extensive research has delved into a variety of pedagogical approaches and the complexity of English phonology, an unanswered question is how high-proficiency EFL learners achieve the elusive goal of native-like pronunciation in spoken English. To this end, this multiple-case study aimed to explore the multifaceted strategies employed by 15 high-proficiency EFL learners who had mastery in pronunciation and were selected using the maximum variation sampling method. Data was gathered through the use of diaries and in-depth semi-structured interviews. The data was analyzed with NVivo software version 10, and two main themes were extracted: teacher-directed (TD) and self-directed (SD) pronunciation learning strategies. Regarding the TD strategies, some participants (46%) acknowledged actively engaging with structured tasks and assignments facilitated by teachers. They highlighted the role of in-class (36%) and out-of-class (64%) activities in their journey to master pronunciation. The SD strategies were reported by about half of the participants (54%) in their quest for pronunciation mastery, which included self-talk (48%), podcast listening (29%), shadowing (12%), and reading aloud (11%). This study contributes valuable insights into relevant literature and offers evidence of the interconnectedness of TD and SD strategies in pronunciation improvement. The findings have several implications for further research or practice about pronunciation mastery.

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Asbads are a type of windmill with vertical axis which are considered as the oldest windmills in the world. These mills have been constructed in pre-Islamic eras in Sistan and southern part of Khorasan. From a long time ago, Sistan has been considered as the Iran’s store of wheat. Climate and appropriate soil along with the water of big Hirmand River have provided an appropriate situation for agricultural farms and particularly for wheat. As said, Sistan had been known as a wheat store of Iran. 120-day wind of Sistan is a natural feature of Sistan region. In this region, in the second half of warm season, when wheat is being harvested, vigorous winds start to blow. All of these characteristics provide the situation for constructing the Asbads which are considered as a great innovative production. In this regard there are different evidences which show that the oldest windmills are built at the east of Iran and in Sistan area. Main building of Asbad includes a two-storey building in which upper storey is usually open-ended. Moreover half of the building which is subjected to the wind is constructed completely open and the other half is completely enclosed. The part which is behind the wind side is also entirely open. Asbads have had an important role in past people’s livelihood and also is a sample of combination of traditional architecture with the needs of ecology which is considered as eco-friendly energy. Regarding to the Asbads’ unique characteristic, functional and esthetics features, recognizing them is of special importance. The concern in this research is to know how many groups traditional windmills or Asbads in Sistan are divided to, where they spread in Iran and what are the different types of them? More of the Asbads of Iran have been located in east and south-east of Iran where valuable winds blow during the whole year. Different types of 120-day winds blow in north of Sistan and south of Khorasan in second half of warm season. Asbads with traditional and domestic style provide opportunity for residents to utilize renewable energies. Different types of Asbads have spread all over “big Sistan” which are constructed differently according to the circumstances and ability of residents. Due to this fact, some of them have simple and rural forms and the others are more complicated. However, their functions are the same but their sizes and their efficiencies are different. Studies show that we can break Asbads down into the three groups such as simple Asbads, cylinder Asbads and corridor ones.

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Study of the relationship between two important variables, emotional intelligence and leadership style, has been the main purpose of this research. The population under study consists of 266 marketing and sales managers from Mashhad food and automobile industries from which a sample of 73 peaple was drawn. Data was collected by means of two questionnaires, including Weisinger’s emotional intelligence questionnair and Barak’s leadership style questionnair. Face validity and split half method were used to determine the questionnaires validity and reliability respectively. The result of split half reliability for emotional intelligence and leadership style questionnaires was known to be .083 and .079 respectively, which the results of the research revealed that there is a positive and meaningful relation between emotional intelligence and transformational leadership style, and a negative relation between emotional intelligence and transactional leadership style of the population under study.

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A novel chemical solution deposition approach is reported for the deposition of nickel catalyst, which is a required step for the growth of carbon nanotubes (CNTs). In this work, after catalyst coating, vertically aligned CNTs have been grown on the silicon oxide and silicon surfaces. The results were studied using field emission scanning electron microscopy (SEM), Raman and X-ray diffraction. This technique has a high selectivity over the size of the catalyst nanoparticles, which results in the simple controlling of the average diameter of grown CNTs in the range of 30 to 150 nm. In addition, this approach leads to a more conformal coating on the surface of the sample in comparison with traditional vacuum-based deposition techniques, enabling the growth of CNTs on highly rough surfaces. The proposed catalyst deposition technique is a fast, inexpensive and simple Nickel catalyst deposition method that can significantly facilitate the growth process of CNTs

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In this paper, the Finite Cell Method (FCM) is used to predict the ductile damage and crack evolution in ductile materials under small strains and nonlinear isotropic hardening conditions. In the first step, a fully coupled elastic-plastic-damage model based on modified Lemaitre ductile damage model was developed and implemented into FCM implicit codes. Also the effect of micro-crack closure, which may dramatically decrease the rate of damage growth under compression, was incorporated and its computational implementation was discussed. The FCM is the result of combining the p-version finite element and fictitious domain methods, and has been shown to be effective in solving problems with complicated geometries for which the meshing procedure can be quite expensive. It, therefore, combines fast and simple mesh generation with a high convergence rate inherited from p-FEM. The performance of the FCM and damage model is verified by means of numerical examples and the results were compared with exprimental observation. The results showed that modified Lemaitre damage model can be used as a quick and accurate tool to predict ductile damage and fracture in metal forming processes.

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Objective: The prevalence of respiratory allergies, especially those induced by fungi such as Alternaria alternata, has dramatically increased over the past decade. This increase has caused major health problems worldwide. This study aimed to investigate the role of A. alternata in the etiology of allergic asthma, by using the skin prick test and assessment of IgE specific to the fungus in the patient's sera. Methods: This study enrolled 202 patients with allergic asthma, aged 12 to 83 years. Participants included 40.1% males and 59.9% females who were enrolled after recording demographic information. A skin prick test with the whole cellextract of A. alternata was performed on the epidermis of the patients' forearms. Histamine and normal saline were used as positive and negative controls, respectively. Serum levels of IgE specific for A. alternata were measured for all patients using the ImmunoCAP Phadiatop method in which the specific A. alternata allergen cocktail that connected to the solid phase reacted to IgE antibodies in each patient's sera. Data were analyzed by analysis of variance and chi-square tests. Results: Among 202 patients with allergic asthma, 14 (6.93%) had mild asthma, 73 (36.10%) were moderate asthmatics and 115 (56.90%) had severe asthma. In total, 14 (6.93%) patients were positive for both the skin test and IgE specific to A. alternata, 35 (17.33%) had negative specific IgE and positive skin test results, and 36 (17.82%) had a positive specific IgE and negative skin test. A total of 117 (57.92%) patients were negative for both tests. Conclusion: The results of this study showed the presence of IgE specific for A. alternata in 50 of 202 (24.75%) patients diagnosed with allergic asthma. The skin prick test was successfully used as a screening test. The results were further confirmed by solid-phase immunoassay of the IgE specific for A. alternata crude allergenic extract.

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One of the main challenges of simulating virtual objects by haptic devices is instability, especially in simulating stiff objects. In this paper, a stability criterion for a haptic device is derived using Lyapunov approach. The haptic device is modeled as a mass and viscous friction, which has to simulate the touching a virtual environment (VE) with specified stiffness and damping. Dynamic equations and state-space equations are derived with assumption of small values of sampling time, time delay and virtual damping. A Lyapunov function is proposed, consisting of summation of kinetic and potential energy of the system, plus two unknown terms. Each one of these two unknown terms is a function of one system states (i.e. position and velocity). These two functions are determined so that, from one side the Lyapunov function be positive definite, and from the other side the stability criterion is reached with putting time derivation of the Lyapunov function negative. The stability condition determined by this method is a linear criterion between maximum permissible virtual stiffness, virtual damping of the VE, physical damping of the haptic device, sampling time and time delay, and is consistent with the results of previous researches with linear methods. The importance of the presented analysis in this paper is that this method can be extended by adding new terms to the Lyapunov function, to remove some limitations and to take into account nonlinear effects. Presented criterion and its results are verified by experiments on KUKA robot.

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Large-scale spatial skeletal structures belong to a special kind of 3D structures widely used in exhibition centers, supermarkets, sport stadiums, airports, etc., to cover large surfaces without intermediate columns. Space structures are often categorized as grids, domes and barrel vaults. Double layer grid structures are classical instances of prefabricated space structures and also the most popular forms which are frequently used nowadays.Topology optimization of large-scale skeletal structures has been recognized as one of the most challenging tasks in structural design. In topology optimization of these structures with discrete cross-sectional areas, the performance of meta-heuristic optimization algorithms can be increased if they are combined with continuous-based topology optimization methods. In this article, a hybrid methodology combining evolutionary structural optimization (ESO) and harmony search algorithm (HSA) methods is proposed for topologyoptimization of double layer grid structures subject to vertical load. In the present methodology, which is called ESO-HSA method, the size optimization of double layer grid structures is first performed by the ESO. Then, the outcomes of the ESO are used to improve the HSA. In fact, a sensitivity analysis is carried out using an optimization method (ESO) to determine more important members based on the cross-sectional areas of members. Then, the obtained optimum cross-sectional areas of members are used to enhance the HSA through two modifications. Structural weight is minimized against constraints on the displacements of nodes, internal stresses and element slenderness ratio. In topology optimization of double layer grid structures, the geometry of the structure, support locations and coordinates of nodes are fixed and this structure is assumed as a ground structure. Presence/absence of bottom nodes, and element cross-sectional areas are selected as design variables. In topology optimization of the ground structure, tabulating of nodes is carried out based on structural symmetry: this leads to reduce complexity of design space and nodes are removed in groups of 8, 4 or 1. The presence or absence of each node group is determined by a variable (topology variable) which takes the value of 1 and 0 for the two cases, respectively. The ground structure is assumed to be supported at the perimeter nodes of the bottom grid. Therefore, these supported nodes will not be removed from the ground structure. In order to achieve a practical structure, the existence of nodes in the top grid will not be considered as a variable. This causes the load bearing areas of top layer nodes to remain constant. Also, discrete variables are used to optimize the cross-sectional area of structural members. These variables are selected from pipe sections with specified thickness and outer diameter. Therefore, in topology optimization problem, the number of design variables is the summation of the number of compressive and tensile element types and the number of topology variables. The proposed approach is successfully tested in topology optimization problem of double layer grid structure. In particular, ESO-HSA is very competitive with other metaheuristic methods recently published in literature and can always find the best design overall. Also, it is determined that HSA method can find better answer in the topology optimization of large-scale skeletal structures, in comparison to optimum structures attained by the GSA and ICA.

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Recently, the phase field approach has gained popularity as a versatile tool for simulating crack propagation. The purpose of this study is to employ the capabilities of the phase field method for crack growth modeling in complex structures such as porous media. The phase field method does not need predefined cracks and it can simulate curvilinear crack path. This goal is accomplished by replacing the sharp discontinuities with a scalar damage phase field parameter representing the diffuse crack topology. To simulate brittle fracture in this study, the equations of elastic displacement field and fracture phase field are first introduced. Afterwards, using the weak form of the equations, the staggered solution of the equations is performed. To implement the equations in the finite element method, the Abaqus software with User Element Subroutine (UEL) is used. Given that the bone structure is somehow a porous structure, a representative volume element of the bone is selected for phase field simulation. In order to verify the developed model, the tensile test of the single edge notched specimen has been simulated. Subsequently, crack propagation in a porous media with different porosities under tensile loading was simulated. The simulation results illustrate the capability of the phase field method in predicting crack growth in geometrically complex structures. In addition, the load-carrying capacity or the strength of the porous structure continuously decreases with increasing porosity and noteworthy is that such a strength is suddenly decreased around a critical porosity value.

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Many companies are dependent on purchasing the required professional services (such as managerial, marketing, accounting, legal, and IT services) from specialist contractors. The contract between such contractors and clients forms an agency relationship, so the agency theory may be used to regulate the relationship between them. However, since the abstract knowledge is the subject of exchange between the client and professional service provider and there is a knowledge asymmetry between these two parties, the application of agency theory as it is used for traditional owner-manager agency relationship is not possible for principal-professional agent relations. In this article, we expand the agency theory to be applicable in such agency relationships. We suggest that a combination of behavior-based and outcome-based contracts be employed in principal-professional agent relationships, if possible. Moreover, we discuss why it is very hard or even impossible to have a direct control over professional service contractor and to measure the outcomes of its services. We finally propose two alternative mechanisms (1-trust and self-control, and 2-indirect control) for reducing opportunistic behaviors and solving some agency problems occurring in principal-professional agent relations.

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A suitable design is one design can achieve to its aims with minimum cost and needing to less computing time. In civil engineering due to survey of large scale structures and large number of design variables, it is so hard achieving to such design only based on experience and therefore optimization methods came to help designer as useful tools in order to find an economic and efficient design. Structural optimization can be defined as a process of dealing with the optimal design of various structures. Ausual objective function is the weight of the structure. In general, there are three main categories in structural optimization applications, namely, size, topology and geometry (shape) optimization.Cellular automata (CA) is a computationally efficient and robust tool to simply implement complex computations. As CA is simple to be implemented and can deal with complex problems without extensive mathematical computations, it is widely used in various fields of science and engineering.In recent years, various meta-heuristic inspired optimization methods have been developed.Almost all of metaheuristic algorithms come up with an idea of employing a particular process or event in nature as a source of inspiration for the development of optimization algorithm. The Cuttlefish algorithm is inspired based on the color changing behavior of cuttlefish to find the optimal solution. The patterns and colors seen in cuttlefish are produced by reflected light from different layers of cells including (chromatophores, leucophores and iridophores) stacked together, and it is the combination of certain cells at once that allows cuttlefish to possess such a large array of patterns and colors.In this article, cuttlefish algorithm (CFA)combined with cellular automata (CA) and were used for optimization truss structures.First, cellular automata and the Moor neighboring cells are defined and to the number ofsquares of the cell number ofcellular automata lattice( )is selected from the  best population. Then, the variables vector and their objective function of selected population are placed in each cell of the cellular automata.In a Moor neighboring, nine cells are compared to each other and the best answer ( )is selected and that is used to create new population.Finally, the best person in thenew population will be selected and itreplacedwith the worst person in the cellular automata, and thus the cellular automatais updated. Some benchmark numerical examples were solved using the CFA and CA-CFA algorithms, and the results of the numerical examples showed that the enhanced algorithm performancesbetter in size and topology optimization of truss structures than cuttlefish algorithm and other methods introduced in the literature. Finally, it can be concluded that the convergence speed of the improved algorithm compared with previous approaches is higher and its ability to achieve the desired values is better too.

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Problem definition is the most vital and important step in system dynamics approach. It is the basis for other steps of dynamic modeling and one of the main conditions in the effectiveness of modeling and its success. Considering its importance, there is scant literature on process of problem definition and attributes as well as indicators of dynamic problems. With aims to explain the problem definition, this article creates problem definition framework through the systematic and structured process by extracting the indicators and factors that determine a dynamic problem. At this point all the articles listed at the first two rounds of system dynamics research conferences in 1976 and 1981 and also 33 around of the system dynamics conference from 1983 to 2015 as well as the Journal of System Dynamics Review (SDR) and scientific databases include Elsevier, Wiley, Springer and Emerald were examined. Finally, a framework was designed with 6 indicators including structure of the problem, problem`s stakeholders, border of problem, problem complexity, dynamics and nature of the problem, which altogether consists of 24 indexes. A comprehensive framework for the diagnosis of dynamics problem is main finding of this paper.

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In addition to the need for lightweight properties, the metallic bipolar plates in the PEM fuel cells should work in a humid and acidic environment. Due to its low density and excellent corrosion resistance, titanium is a proper candidate for manufacturing bipolar plates. In this paper, the manufacturing of bipolar plates made of commercially pure titanium with an initial thickness of 0.1 mm was investigated using the stamping process. A four-channel die with a parallel flow field was used in the experiments. To estimate the formability of microchannels of the bipolar plates, the response surface method, genetic algorithm, and adaptive neural fuzzy inference system were employed. Die clearance, stamping speed, and friction coefficient between the sheet and die were considered input variables, whereas the die filling rate was as output. The designed experiments using the response surface method were used to train the meta-heuristic techniques. The results showed that the regression model obtained from the response surface method predicts the die filling rate with acceptable accuracy. Furthermore, the coefficients of the equation obtained from the regression have been improved using the genetic algorithm and the error rate has been reduced by about 53%. Finally, an adaptive neural fuzzy inference system was used to predict the die filling. The results showed that the proposed system is very feasible and approximates the maximum filling rate with high accuracy.

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The systems dynamics emphasize the participation of individuals in modeling as well as modeling evaluation. In recent years, participative model building methods have been developed, both individually and in groups, as well as crowd model building, which are based on the mass participation of people through the Web 2 and social networks. However, so far no systematic study has been done to evaluate the effectiveness and compare these modeling methods. On the other hand, in the development of modeling methods, especially crowd model building; special features and characteristics have been enumerated for each of them, which needs to be carefully examined by evaluating them. Therefore, this article seeks to systematically evaluate and compare the crowd and group model building. For this purpose, these two modeling methods have been studied through an online questionnaire. The results showed that the participants acknowledged the positive effect of crowd and group model building sessions in achieving the goals as well as the importance and usefulness of these sessions. However, the results showed that crowd model building is more useful in recognizing different dimensions of crowdfunding with a divergent view, dissemination of topics, and culture building in society, while group model building has been more useful in deepening peoplechr('39')s knowledge of the dimensions of crowdfunding with a convergent view, increasing the commitment of individuals. The results also showed that the diversity of individuals and the informal structure of the sessions have a significant effect on the success of crowd and group model building.