Showing 33 results for تبری
Volume 1, Issue 3 (Summer 2021)
Abstract
In the philosophy of religion, Divine Agency has been related to how God does his action in the human world and the physical world. Polkinghorne has presented a particular method to answer this question. His theological approach has been a combination of Classical Theology and Process Theology. On the one hand, he has said that the God defined in Classical Theology is too unavailable, and on the other hand, he has criticized the Process approach to God. Polkinghorne has established that Epistemology is equal to Ontology, and based on this fact, he has explained his Critical Realism. In his view, the guaranty of reality is not to understand it but is its objectivity. Uncertain situations in Modern Physics presented in Einsteinian Relativity, Quantum Theory, and Chaos Theory is the main areas Polkinghorne has constructed his specific theory about Divine Agency on them.
Volume 3, Issue 1 (spring 2022)
Abstract
Aims: Pedestrians are very important because of their characteristics in creating social interactions, functional and environmental goals. The main purpose of this study was to investigate and measure the effects of pedestrian paths on improving the quality of urban environment and comparing the 15 Khordad and Saf pedestrians.
Method: In order to conduct this research, first, using descriptive and analytical research method, physical, functional (functional) and perceptual variables affecting the quality of pedestrians were extracted. The above variables were evaluated by the specified indicators in the 15th of Khordad and Saf pedestrians. Some indicators were evaluated in pedestrian paths using expert observation and through maps and tables. For others, the questionnaire was used to measure physical, functional (functional) and perceptual variables. The questionnaire was evaluated for reliability and validity by Cronbach's elfaya method and reviewed through the initial test of internal dissonances.
Results: The results of the studies showed that there was a significant relationship between the variables of facilities and facilities (physical), economic and service performance (functional-functional) and order (perceptual) with improving the quality of the environment. On the other hand, there is no significant relationship between increasing the sense of belonging to the place by creating the 15th of Khordad and Saf pedestrians and increasing social interactions.
Volume 7, Issue 1 (Spring & Summer 2003)
Abstract
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Volume 9, Issue 3 (Vol.9, No.3 (Tome 45), July, August & September 2018, (Articles in Persian) 2018)
Abstract
Task-based language teaching (TBLT) characterized by involving language learners in meaning-focused activities with some focus-on-form has enjoyed increasing popularity in the past two decades. Meanwhile, ample theoretical and empirical evidence has been presented to account for different task design features that influence language learning and learners’ performance. However, selecting and sequencing suitable tasks as well as recognizing appropriate task combinations that can provide a good opportunity for learning are still topical issues in SLA research (Robinson, 2011; Skehan, 2014).
Considering this interest, this study set out to examine whether changes in the cognitive demands of tasks and their implementation condition (operationalized by individual and collaborative writing) would lead to differential improvement in language learners’ writing performance. The study also explored the relationship between an under-researched learner factor (self-regulation) and EFL learners’ written performance in individual and collaborative tasks varying in terms of cognitive complexity. The novelty of the present study lies primarily in its considering the combined effect of task complexity and task condition on writing—which is a somewhat neglected mode in research on TBLT—of EFL learners.
Although different models and criteria have been proposed to account for task complexity, psycholinguistic rationales have drawn more support recently. Skehan’s (1998, 2009) trade-off hypothesis and Robinson’s (2001, 2003, 2009) cognition hypothesis are two influential models in vogue toady. Different views on attentional capacity of human beings have led Skehan and Robinson to have almost contradicting predictions on learners’ performance in tasks with different levels of cognitive complexity. Robinson (2001, 2003), assuming multiple-resource model of attention, holds the view that performing some complex tasks (e.g., those made complex by the number of elements) pushes learners to make efficient use of their attentional resources and produce more accurate and complex output. Contrarily, Skehan (1998), acknowledging the limited attentional capacity of learners, claims that simultaneous increase in accuracy and syntactic complexity of linguistic output is not feasible just due to the manipulation of task complexity. He claims that learners carrying out cognitively demanding tasks have to prioritize one (accuracy or complexity) at the expense of the other.
Two research questions were formulated for the present study: (a) Do task complexity, task condition, and their interaction affect the accuracy, syntactic complexity, and fluency (CAF) of language learners’ written performance? (b) Is there any relationship between self-regulation of language learners and their performance in individual and collaborative writing tasks varying in terms of cognitive complexity? To answer these questions, 122 EFL learners whose homogeneity was ensured by Nelson English Language Proficiency Test were recruited. They were randomly assigned into four groups. The participants in four groups carried out the tasks which were different in terms of cognitive demands (simple/complex) and their implementation conditions (individual/collaborative). Task complexity was manipulated by the number of elements that participants had to consider while performing the writing task.
The collected data were analyzed by MANOVA and Pearson correlation after checking for the assumptions underlying these statistical analyses. Findings revealed that task condition had a significant effect on the writing accuracy of language learners but manipulation of task complexity did not affect three writing dimensions, i.e., syntactic complexity, accuracy, and fluency (CAF) significantly. These findings lent partial support to Skehan’s (2009) trade-off approach toward task design and also Vygotsky’s (1978) social constructivism. Moreover, self-regulation of learners who performed the complex writing task in isolation showed a positive significant correlation with the accuracy of their writing. Robinson (2011) has made a similar prediction regarding the role of individual differences in learners’ performance in complex tasks. The findings add support to the view that selecting appropriate levels of task complexity and suitable task implementation conditions enhance different dimensions of the written performance of language learners. The study calls for more prominent place for task condition and individual differences of learners in the frameworks and models put forward for task designing and sequencing.
Volume 10, Issue 3 (10-2010)
Abstract
The new competitive environment changes the paradigm of power system operation. In the transmission area, open access process provides fair accessibility for all market participants. Congestion management is one of the most important side effects of this new process. This paper proposes a new approach for congestion management which is based on both active and reactive re-dispatch of the network critical buses. The critical buses including both generation and interruptible loads, are determined through a sensitivity analysis. Due to the important effects of the market pricing rules on the congestion cost and its allocation, two types of these rules, namely uniform and pay as bid pricing are investigated in the paper. The numerical results of case studies show the effectiveness of the proposed approach.
Volume 12, Issue 3 (10-2012)
Abstract
Confined masonry consists of load-bearing walls with some slender cast-in-place tie columns connected with tie beams. These confining elements are usually made of reinforced concrete and especially located around the critical points such as openings and corners. Although the response of confined masonry walls has been extensively studied in experimental tests worldwide, the analytical models capable of capturing deformation and strength characteristics of these walls and also technical guidelines which can help engineers to numerically evaluate the seismic resistance of confined masonry structures are rate. In this study, the micro-modeling strategy is adopted for the numerical simulation of unreinforced masonry walls confined by reinforced concrete tie columns and beams. A modified version of general path dependent contact density model is used to simulate the complicated response of brick-mortar interaction in the mixed mode of shear and axial deformations. A nonlinear finite element analysis program called “WCOMD_SJ” is used for this purpose. This program has been developed at University of Tokyo and is an analytical tool for two-dimensional static and dynamic nonlinear analysis of reinforced concrete structures based on fixed smeared crack approach. This program has been modified by the second author for nonlinear macro and micro analysis of masonry structures. In order to validate the analytical approach, experimental test results and gathered data from literature are used. The comparison between experimental and analytical results shows good agreement between analytical and experimental findings. Then through a parametric study, the effect of opening and also the interactional effect of adjacent walls on the lateral response and strength of confined masonry walls are numerically investigated. Finally a simple but rational method for modeling the nonlinear behavior of confined masonry walls is proposed. The comparison between this model and numerical results confirms the reliability of the proposed model. Since available experimental results are rare, an analytical study is also performed for investigating the accuracy of the proposed relations.
Volume 12, Issue 47 (7-2015)
Abstract
Nowadays, the importance of brand concept is so high that some researchers believe that brand is a perfect product and argue the most of the time customers instead of buying a product buy the brand. Therefore recognizing the factors influencing brand choice and investigating the specific features of brand is of importance and requires various studies .the present study aimed at investigating into factors that affect brand choice in food industrial companies . the methodology of this study was applied .research and for data collection. Survey approach was used. The statistical population consisted of buyers in Tehran and statistical sample based on factor analysis were 400 buyers. Based on statistical analyses , 19 factors that affect brand choice were categorized in 4classified: 4 factors namely the simplicity of brand pronunciation, personality and psychological factor, recognition quality and services and famous .further based on qualitative analyses based on qualitative analysis result revealed that "personality and psychological factor" for responding effects in brand choice to great extent
Volume 14, Issue 3 (11-2014)
Abstract
In this research parameters influencing flow pattern and scour around submerged and nonsubmerged series of spur dikes in straight channel were investigated. Scour pattern was investigated for three angles of dikes construction, and three submergence ratio.The result showed that with increasing Froude number and decreaseing submergence ratio, scour decreases. Also because of first spur dike effect on main flow, maximum scour depth in second and third spur dike is less than first one. The location of scour and ridge height change with Froude number, submergence ratio and angle.The three dimention velocity around spur dike were analyzed Then we used flow pattern to forecast scour pattern. In this research parameters influencing flow pattern and scour around submerged and nonsubmerged series of spur dikes in straight channel were investigated. Scour pattern was investigated for three angles of dikes construction, and three submergence ratio.The result showed that with increasing Froude number and decreaseing submergence ratio, scour decreases. Also because of first spur dike effect on main flow, maximum scour depth in second and third spur dike is less than first one. The location of scour and ridge height change with Froude number, submergence ratio and angle.The three dimention velocity around spur dike were analyzed Then we used flow pattern to forecast scour pattern. In this research parameters influencing flow pattern and scour around submerged and nonsubmerged series of spur dikes in straight channel were investigated. Scour pattern was investigated for three angles of dikes construction, and three submergence ratio.The result showed that with increasing Froude number and decreaseing submergence ratio, scour decreases. Also because of first spur dike effect on main flow, maximum scour depth in second and third spur dike is less than first one. The location of scour and ridge height change with Froude number, submergence ratio and angle.The three dimention velocity around spur dike were analyzed Then we used flow pattern to forecast scour pattern. In this research parameters influencing flow pattern and scour around submerged and nonsubmerged series of spur dikes in straight channel were investigated. Scour pattern was investigated for three angles of dikes construction, and three submergence ratio.The result showed that with increasing Froude number and decreaseing submergence ratio, scour decreases. Also because of first spur dike effect on main flow, maximum scour depth in second and third spur dike is less than first one. The location of scour and ridge height change with Froude number, submergence ratio and angle.The three dimention velocity around spur dike were analyzed Then we used flow pattern to forecast scour pattern. In this research parameters influencing flow pattern and scour around submerged and nonsubmerged series of spur dikes in straight channel were investigated. Scour pattern was investigated for three angles of dikes construction, and three submergence ratio.The result showed that with increasing Froude
Volume 14, Issue 13 (First Special Issue 2015)
Abstract
This paper aims at obtaining the dynamic models of twoconstraint-over parallel mechanisms (PM) with 3-DOF (degree of freedom) and 4-DOF, the Tripteron and the Quadrupteron. The reasoning used in this paper is based on a judicious concept in detaching the whole mechanism into several subsystems and consecutive synergies between kinematic analysis, Lagrangian and Newtonian approaches. In this regard, the mechanisms are made equivalent to some subsystems and the equations of kinematic constraints are derived for all subsystems. Afterwards upon resorting to Lagrangian approach and blending it with the latter kinematic relations, the dynamic model of each leg in task space is obtained. The dynamic model of the end- effector is written in virtue of Newton-Euler’s approach where yields to three differential equations. Finally, the problem leads to a system of 12 equations for the Tripteron and 16 equations for the Quadrupteron, which do not need usaul simplifications in such problems. For the sake of comparison, the results are put into contrast by the one obtained with a dynamic analyzer software. The results obtained by both approaches are coherent which affirms the correctness of the proposed algorithm.
Volume 14, Issue 66 (0-0)
Abstract
Volume 14, Issue 70 (0-0)
Abstract
Volume 15, Issue 2 (8-2015)
Abstract
This paper studies the consensus problem of nonlinear leader-following multi-agent systems (MAS). To do this, the error dynamics between the leader agent and follower ones are described via a Takagi-Sugeno (TS) fuzzy model. If the obtained TS fuzzy model is stable, then all of the nonlinear agents reach consensus. The consensus problem is investigated based on the parameterized or fuzzy Lyapunov function combined with a technique of introducing slack matrices. The slack matrices cause to decouple the Lyapunov matrices from systems ones and therefore, sufficient consensus conditions are obtained in terms of linear matrix inequalities (LMIs). The proposed slack matrices add an extra degree-of-freedom to the LMI conditions and also decrease the conservativeness of the LMI-based conditions. Finally, in order to illustrate the effectiveness and merits of the proposed method, a numerical example for the consensus problem of nonlinear leader-follower MAS with thirteen followers is solved.
Volume 15, Issue 9 (11-2015)
Abstract
This research discuss about the effect of simultaneous usage of Propellant Utilization (PU) system and Flight Apparent Velocity Regulation (AVR) system. These systems were used for sending OBC commands to engine for adapting the engine working regime with flight conditions and fame to active control systems. Each of PU and AVR systems has an effective roll in access to final parameters such as mass and velocity at the end of active phase and simultaneous usage of these systems lead to increase the range accuracy and payload mass. We study these effects on final parameters in this paper. Therefore, with dynamic simulation of liquid propellant engine in during of active phase in flight simulator, sending commands of these systems to change the engine working regime is provided. For a specific mission results show that with working of the PU, range increased and presence of AVR, is assist to reach this range in front of disturbance during the flight. Another main result of this research is, increasing of payload mass for a specific mission with simultaneous usage of PU and AVR systems.
Volume 15, Issue 10 (1-2016)
Abstract
In this paper, a useful method proposed for aerodynamic design of Megawatt wind turbine's blade based on Blade Element Momentum (BEM) theory. In this method first a preliminary design is done based on the ideal BEM and then a method have been offered for geometric modifications to approximate the geometry of the blade to a real and functionally one. The advantage of this method is that needed few design parameters that simplify the design procedure, however its results are in good agreement with 5MW NREL reference wind turbine assumed as validation case and show that with use of this method can achieve a good aerodynamic design. then the twist angle has been optimized using Genetic algorithm and Bezier curve with annual energy production (AEP) as the goal function. At the end, a 2.5 MW wind turbine has been design based on this method with considering the Lootak site specifications in province of Sistan and Baloochestan. Then 3D model of the blade has been made and CFD simulation applied on that for showing the designed turbine operation in real conditions and comparison with BEM method and there is acceptable compatibility between two analytical methods.
Volume 15, Issue 83 (12-2018)
Abstract
In this research, the effect of the of sucralose and xylitol on the production of low calorie sour cherry jam was studied. Sugar replacement rates were 25% and 50%, and in this range, six different treatments were prepared using either sweeteners independently or in combination. Chemical, physical and sensory properties on the first day and after 30, 60 and 90 of storage time were analyzed based on factorial design. The results showed that in spite of the effective use of sucralose in reducing calories, but the consistency and sensory properties dropped in the jam prepared with these sweeteners. Compared to the control sample, using of sucralose leads to reduce consistency and a significant increase in water activity (P <0/05) and the incidence of these undesirable changes increased with increasing replacement rates and the use of a combination of sucralose and xylitol reduced the effects of unsuccessful sucralose significantly. Among the parameters studied, pH was not affected by the type and amount of sweeteners. The effect of storage time on the parameters in samples prepared with sucralose was more than that of xylitol containing jams so that reduction of consistency changes were observed in these samples during storage time. In total, samples produced with a replacement rate of 25% were more favorable than the replacement of 50% and samples prepared with 75% sugar, 12.5% sucralose and 12.5% xylitol and 75% sugar, 25% xylitol and without sucralose were the most suitable samples in terms of similarity with the control sample.
Volume 15, Issue 83 (12-2018)
Abstract
Volume 16, Issue 8 (10-2016)
Abstract
Abrasive flow machining (AFM) is a relatively new process with low material removal ratio for deburring, removing recast layers and finishing industrial components with complex shapes among non-conventional machining processes. In this process, the finishing is handled by flowing of the composition of viscoelastic and abrasive particles on workpiece surface, under the pressure of piston. In this research, the abrasive flow machining process of H13 tool steel with applied an external magnetic field around the workpiece for improve the material removal ratio and surface roughness has been investigated and the effect of magnetic field intensity, abrasive particles mesh and the hardness of workpiece as the input parameters on the process outputs including surface roughness and material removal ratio was studied. Also the regression model of MRR and surface roughness was developed and variance analysis was performed. Results of experiments indicated that increase in abrasive-particles mesh leads to decrease surface roughness and material remove ratio and increase in magnetic field intensity causes to increase material removal ratio and decrease surface roughness. Also the material removal ratio is decreased with increasing of workpiece hardness and on the same condition; better surface finish was achieved in the case of harder workpiece.
Volume 16, Issue 9 (11-2016)
Abstract
In this paper design, fabrication and control of a robotic fish with flexible tail was presented. At first, the short introduction of the robotic fish and their common control algorithms were reviewed. At the next step, the proposed mechanism of the robotic fish and its design procedure of the mechanical and electrical subsystems were explained. Mimic of the proposed robot was inspired from the Rainbow trout. The mechanical structure of the robotic fish consists of a body and a flexible tail. Oscillatory actuation of the tail was carried out utilizing a servomotor which was manipulated by pulse width modulation signal. The electrical subsystem of the proposed robot containing the electrical boards, electronic circuits, and a microcontroller are installed on the Aluminum platform which is locating in a sealed case. The flexible tail is attached to the end-side of the sealed case, and the actuating force is transferred to the tail utilizing pulley and cable mechanism. Since the dynamics of the system under investigation is nonlinear, a fuzzy logic controller is proposed to control the movement of the robot for goal seeking purpose. The closed loop simulation of the system was carried using MATLAB software. In addition, experimental investigation of the robotic fish was performed in the laboratory.
Volume 16, Issue 87 (5-2019)
Abstract
Volume 16, Issue 90 (August 2019)
Abstract
Degradation of nutrients and change in the food quantity occur during the food processing; so, the food quality and retention nutrients are of the most important aspects of food processing. In this research, the effect of tomato slices drying process on the kinetics of vitamin C (ascorbic acid) degradation, color changes (L *, a * and b * ) and the specific energy consumption in order to produce tomato powder was investigated during the hot air drying at 45, 60 and 75 °C. This tomato powder was used to produce tomato compact tablets. Also, the effect of tomato dough moisture content (25, 40 and 55 %d.b.) and drying temperature of wet tomato tablet (30, 40 and 50 °C) on vitamin C concentration (as an indicator for retain nutritional) was investigated during the compression and convective drying processes. The results showed that the drying temperature and moisture content had a significant effect on the retention of vitamin C concentration (product health) when the fresh tomato processing and the production of compact tablet were going on. Drying under lower temperatures and moisture contents helps to retain quality and nutritional value (less degradation of vitamin C) of tomato tablets.