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Chromate conversion coating is applied on aluminum 6061. The optimum conditions for chromate bath composition and immersion time are also obtained for standard requirements provision such as corrosion resistance in salt spray test, electrical resistance and coating quality. The applied coatings are electrochemically tested in sea and distilled water. According to Tafel and cyclic polarization curves, the protection mechanism are evaluated in said environments. This evaluation has shown the formation of passive film layer, contains chromate and alumina on the base. The proper behavior of corrosion and electrical conductivity is probably due to this mechanism.

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Aims: Nowadays, one of the most frequent problems that international students face is homesickness. The purpose of this study was investigation of homesickness and coping strategies among the University Technology Malaysia) UTM (international students and finding new research topics for future educational planning research. Methods: This descriptive study was done in August 2010 among the students studying in University Technology Malaysia (UTM). The respondents were international students from different courses in UTM. Fifty questionnaires were randomly distributed among the students at various faculties and residential colleges of the university. The questionnaire included 11 questions, which was developed by the researcher through literature review. Findings: Totally, 50 international students including 24 (48%) female and 26 (52%) male students took part in the study. There were different reported causes of homesickness by the respondents that were classified into four aspects: "social", "psychological", "physical" and "academic”. The findings showed the most important reason for homesickness has been cultural differences between the countries. Accordingly, 75% of the respondents (n=38) reported social customs as the first reason for international students' homesickness. Conclusion: The research results indicated that missing family was the most important factor that influenced international students to feel homesick. According to this study, the best and effective way to manage homesickness was to call family and friend(s).

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This paper aims at a Jungian reading of Shazdeh Ehtejab and thus tries to find the traces of archetypes in the novel. Among the most important archetypes and primordial images that have found expression in the text, one can mention the hero archetypes, the images of water, fire, desert, colors and numbers along with the archetypes associated with Jung’s theory of individuation, i.e., the shadow, the persona and the anima. I have tried to use this conceptual framework to shed light on the way one can interpret different characters of Golshiri’s novel. Thus in my reading the grandfather symbolizes the devil while the prince himself is the exemplification of the hero archetype

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Research subject: Global warming is the most important worldwide problem. CO₂ is one of the greenhouse gasses and its emission to the atmosphere causes global warming to increase. Porous adsorbents are great candidates for CO₂ adsorption and graphene aerogels are porous nanostructures with very low density and hierarchical porosity which is suitable for CO₂ adsorption. The source of pristine graphite for graphene oxide synthesis as a precursor plays a vital role in graphene aerogel nanostructure.  
Research approach: In the current study, graphene oxide by modified Hummers method was synthesized with three different graphite sources. Graphene aerogels were prepared with synthesized graphene oxides via hydrothermal and freeze-drying methods to investigate their effect on graphene aerogel nanostructure. Finally, the CO₂ adsorption of graphene aerogels was evaluated. The samples were characterized by FTIR, XRD, SEM, and BET analysis.
Main results: The results indicated that the source of graphite has a significant role in the process of oxidation of graphene oxide by the modified Hummers method. XRD results of graphene oxides showed successful oxidation of graphite. The normalizing FTIR peaks of graphene oxides showed different intensities of oxygenated functional group peaks. FE-SEM results of graphene aerogels showed that less oxidation of graphite powder caused agglomeration of graphite plates and thick walls were formed. The macropore size in the structure of obtained aerogels (GAB and GAE) was 2.28 and 3.84 µm respectively which affected the CO₂ adsorption. Larger pores led to easier mass transfer of CO₂ molecules and higher CO₂ adsorption was achieved. Moreover, the high meso and micro surface area (111 and 115 m²/g respectively) in GAE increased CO₂ adsorption up to 1.04 mmol/g compared to GAB (0.724 mmol/g).  

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This article attempts to answer the following questions in a descriptive-analytical way: What is the reason for Baumgarten`s use of poetry to demonstrate the independence of aesthetics? What are Kantchr('39')s views on the place of poetry in aesthetics? and what are the differences between them on this issue? The purpose of this article is to clarify the superior art of one of the followers of the rationalist school by looking at Kantchr('39')s view. The results show that due to the beliefs of many aestheticians the words and the sounds are one of the most important aspects of the human soul`s motivating. In the Age of Enlightenment, Baumgarten continued by examining the influence of words and its effect on the emotions, passions by referring to the Christian belief, especially in one of the pietist`s campaigns the Protestantism. Kant separates poetry from rhetoric as a whole, he thought about his attitude, especially about the beauty associated with fine arts such as poetry, the relation between form and content of words, the rich content of words, and the grandeur of content and dignity similar to Baumgarten. The prominent difference is in the free play that Kant considers the poetry between sensibility and understanding and in the natural beauty with regard to form and the independent beauty in the fine arts. Free play has not come to Baumgarten`s ideas. Nor is there any trace of Baumgarten`s perfection in the beauty of the pure form or the free beauty in the Kantian approach to poetry.

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The impact of geographical phenomena is plentiful on human and his life. These impacts are seen at least on attraction and distribution of human specise and kind and form of habitations and settlement sites, the movement of settlement sites, exploitation rate of natural resourses, population, and etc. In this article it is tried to verify the role of geography and especially hydrology on formation and collapse of various civilizations of Sistan and Zahak domain based on archaeologic surveys. The most important objectives of this research are the foundation of settlement history, period of abandonment of sites and all its causes in each of the regions under study. Investigation method was field and systematic surveys during which distinctive cultural samples (pottery) were compiled and then they were studied from archaeological view point. The determination of settlement patterns of the region provided the essential device for reconstructing past geographic environments in different periods (prehistoric, historic period and Islamic period), based on the findings of the project.

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In ancient times, symbolic figures and badges in addition to decorative aspects represented important issues regarding culture, art and even social structures of a state and country. In the Sassanid period, symbolic figures (patterns) also boomed with respect to the interfusion of religion and politics, so that some examples of these symbolic figures can be seen in most of the artworks remained of the Sassanid period. The stucco art during the Sassanid era was one of the most developed arts which have reached the peak of its maturity in this period compared to the preceding periods and witnessed its widespread use in various symbolic forms in Sassanid buildings and palaces. The study of symbolic plant figures of the Sassanid period is a necessity that has unfortunately not been studied independently and extensively so far. With respect to the object of study, the present research is of a fundamental type and with respect to its nature and methodology, it is a historical study. The result of this research indicates that most of the symbolic motifs (patterns) found in the Sassanid stuccos religious origin; although these figures have been depicted in form of numerous and diverse plant figures, each of them is considered as a symbol of religious beliefs. Grapes and the tree of life are among the symbols symbolize fertility, blessing, and immortality in Iran and have always been seen in the stucco works during this period; also, the lotus figures represent one of the deities in Mazdisna religion.

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 The problem of the research is that what is the characteristic aspect of Goethe's attitude towards nature and the depiction of nature in the works of German romantic painters? Therefore, the specific aspect of their attitude towards nature is analyzed in a descriptive-comparative way. Goethe, especially in his youth, in addition to the influence he received from Rousseau, Herder and the stormy and stress pre-romantic movement, had a more romantic attitude towards nature, and in general, nature for him, in his poems and some works, means the life of primitive societies, simplicity and untouchedness in front of civilization. (Rousseau), the spontaneity and immediacy of perception of nature of nature related  to people's life and art, is beautiful nature and God, all of which are considered a kind of romantic perception of nature. Although he also defends classicism, Faust seems to be influenced by the visual point of view of romantic artists. This research comes to this conclusion from the study of Friedrich and Runge's attitude towards nature. It is more romantic. Friedrich moved from the conventionalistic symbolism of his early works to a more refined and poetic naturalism based on Goethe's mood and considered the perspective of the subject to nature in his paintings. Despite Goethe's advice, in his short life, Runge showed the romantic concept of "Hieroglyph of Nature" as an essential element of language and culture.

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This paper proposes a new hierarchical identification method for fractional-order systems. In this method, a SISO (single input, single output) state space model has been considered in which parameters and also state variables should be estimated.  By using a linear transformation and a shift operator, the system will be transformed into a form appropriate for identification of a fractional-order system. Then, the unknown parameters will be identified through a recursive least squares method and the states will be estimated using a fractional order Kalman filter. This identification method is based on the hierarchical identification principle that reduces the computational burden and is easy to implement on computer. The promising performance of the proposed method is verified using two stable fractional-order systems.    

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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.

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In this paper, the stability problem of nonlinear first order hyperbolic partial differential equations (PDE) systems is investigated. Based on Lyapunov stability theorem, the sufficient conditions to guarantee the stability of Takagi-Sugeno (TS) fuzzy hyperbolic PDE model are achieved in terms of spatially varying linear matrix inequalities (SVLMI). To investigate the exponentially stabilization of nonlinear first order hyperbolic PDE systems, a fuzzy Lyapunov function is considered. Then, some new space varying slack matrices are introduced to conduct the stability analysis. The proposed stability conditions are more relaxed than the newly published one. Furthermore, the problem of applying some constraints on control input is studied through this paper. Hence, the performance of the controller is improved in the proposed approach. Finally, in order to evaluate the validity of the proposed approach, a practical application of nonisothermal plug flow reactor (PFR) is considered.  

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Among the various of Sasanian kings, Narseh (293-302 A.D.) is the one whose important and striking rock relief remained at Naqsh-i Rustam in Iran’s Fars province. This relief records investiture ceremony from Anahita ( known as Goddess of fertility and protector of water). Until now, various views and interprations have been put forwarded about the real identity and historical theme of this relief. But the attribution of a lady to Shapurdokhtak II (Narseh`s wife) is the latest and most controversial view given by Alireza Shapur Shahbazi, who has conducted excavations and archaeological studies at Takht-i Jamshid for several years. In fact, this attribution has also provoked the authors of the present article hence; he has tried to highlight the depiction through opinions of various researches. The present study supports the accuracy and validity of the attributed lady to water goddess Anahita and refuses other theories.

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Precast segmental construction methods can decrease bridge construction costs by reducing construction time while maintaining quality control. In addition, the absence of scaffold can minimize traffic congestion and environmental impact. Because of these great advantages of using the precast segmental bridges, their usage is increasing in the world, but it is limited in high seismicity areas due to lack of sufficient knowledge about the dynamic response under seismic loads. According to the precast construction of these types of bridges and their post-tensioning contact on segment joints, it is expected that under earthquake excitation specialy vertical earthquake, superstructure behavior is affected by joints operation in the presence of long-term loads. This issue is very probable in non-continuous post-tensioned bridges. This study is trying to investigate the effects of vertical earthquake on the superstructure of the bridges in near-fault regions by studying a sample model and obtaining structure response including joints response and their openings, force-displacement response of the system, stress and strain in concrete and cables and the level of nonlinearity of them.
Recent research has shown that segment joints can undergo very large rotations that open up gaps in the superstructure and The primary seismic concerns regarding segmental construction are focused on the behavior of joints between segments as no mild reinforcement crosses such as joints. The lack of reinforcement across segment joints allows to an increased rate of construction, yet creates inherent regions of weakness that act as crack initiators and can result in large localized rotations. According to phase I experiment results by Megally et al. [1-3] which are concentrated in regions of high moment and low shear (i.e. near midspan), models were created using the computer software OpenSees V2.4.4 and using detailed 2D nonlinear time history analysis under a suite of ten near-field earthquake records to quantify effect of vertical motion on the joint response. The prototype bridge structure used for this study is single-cell box girder bridge that consist of a 50m span, sixteen 3m segments long with unbonded tendons constructed with the span by span construction method. The segments of the superstructure are modelled using linear elastic frame type members except for a region at the ends of each segment which is discretized into several axial non-linear zerolength springs. The springs are connected to the ends of the superstructure beam elements through rigid body links. Results indicate that the vertical components of earthquake can affect the response of these bridges and segment-to-segment joints opening are very probable particularly at the mid-span joints and superstructure can collapse under upward acceleration demand because of concentrate greater part of concrete on top flange and lack of tension material on top of joints or sliding on elastomer caused by decrease of effective weight. the joint compressive strain remained way below the concrete spalling limit state minimizing the damage and stiffness reduction of the superstructure; the cables remained in the elastic range and closed all joints after earthquake even high seismic intensity levels and the residual vertical displacements were negligible.

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Development of wave energy convertors (WEC) is one of the main challenges that naval architectures have encountered, recently. One of the most important approaches before construction of WECs is the evaluation of their conceptual models in computational fluid dynamics (CFD) software. Therefore, in the current article, an innovative model of wave energy convertor is presented and hydrodynamic performance of proposed model in Persian Gulf has been examined. For accurate simulation of dynamics of WEC, mesh morphing technique is utilized. Since the presented WEC is an innovative design and there is no experimental result for validation purpose, it is tried to verify the numerical setup using similar experimental problems which have the various characteristics of the considered problem. Then, several different geometries including flat and foil pedals, and big and small semi-spherical pedals as a part of WEC have been analyzed, numerically. Small semi-spherical pedal has been determined as the best possible geometry. Number of pedals has been another parameter which has been studied and eight pedals model has been recognized as optimum choice. Finally, optimum WEC has been simulated in nine different waves and the results have been presented.

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Stress urinary incontinence (SUI) is characterized by the involuntary transurethral leakage of urine caused by an increase in abdominal pressure in the lack of an adequate bladder‎ ‎contraction that raises the vesical pressure to a level that exceeds urethral pressure‎. ‎Adult women are most commonly affected by SUI which is believed to be caused in part by‎ ‎injuries to the pelvic floor sustained during childbirth‎. ‎Despite the large number of women affected by SUI‎, ‎little is known about the mechanisms associated with the maintenance of urinary continence in women‎. ‎The work in this ‎research ‎focuses on studying the behavior of the bladder and the dynamics of the urine during an increase in abdominal pressure like a cough‎. ‎The computational model is developed by using the Finite Elements Method (FEM) and Fluid-structure interaction (FSI) techniques. ‎The results show a good accordance between the clinical data and predicted values of the computational models. ‎Simulated pressure is more accurate in the model in which non-linear material properties are utilized. The results of the computational methods indicate that by using numerical techniques and simplification of the physics of biological systems, clinical results can be reached in virtual environments in order to understand pathological mechanisms.

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Underbalanced drilling and managed pressure drilling with foam have been gained attention of the world oil companies due to its many benefits. The advantages of this method include oil and gas production during drilling, high-speed drilling, drill bit life increase, better cutting transfer and reduced formation damage. In this paper cutting handling by foam was investigated in which foam was assumed to be a homogeneous, single-phase, compressible and non-Newtonian fluid whose rheological properties can be well described by power law model. The assumptions and governing equations of transient two-fluid model were expressed in Euler-Euler coordinate for fluid-particle (foam-cuttings). The upstream method is used to discretizing the equations and the results of the numerical solution are reported in the form of pressure, speed, cutting concentration, quality and density of the foam logs along the well. The impact of back-pressure, ROP, injection rate of gas and liquid, shape and size of cuttings, water influx and oil production on cutting concentration and bottom-hole pressure have been investigated. With increasing parameters such as back-pressure, liquid and gas flow rate, size of the cuttings and ROP, bottom hole pressure and cutting concentration increases. Cutting concentration decreases with increasing liquid and gas flow rate and increases by increasing back-pressure, cutting size and ROP. For validating, the results of the numerical solution are compared with field data obtained from well FR-1 located in the Santa Catarina state of Brazil which show about 16.5 percent errors.

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Kooh-e Khajeh (Kajeh Mountain), with 120m height and 2-2.5km in diameter, is located at Hamoon Lake like an island. Since the archaic era, due to its specific geopolitical location, religious sacredness, and the natural beauty especially at the times of water-richness at Hamoon, this place caused the formation of settlements. Based on an intensive archaeological survey conducted in this region, seventeen sites have been identified of which thirteen possess earthenware. Through typological and chronological studies of potteries found at surface level, two era of settlement have been identified in this Mount: one refers to the pre-Islam era beginning from 3rd century B.C. until the end of Sassanians; the second belongs to the Islamic era particularly on the basis of glazed potteries scattered on the surface as well as some structures built during 6th and 8th century Hegira. The buildings and structures related to the pre-Islam era include palaces, defensive forts and citadels, and temples, whereas; the buildings of the Islamic era are exclusively related to some religious places such as shrines, mausoleums and cemeteries.

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To improve solar energy gain by the photovoltaic (PV) modules, a novel double-axis solar tracker was developed in the present study. The proposed system worked based on both active and passive methods of sun tracking using electromotor and gas actuator, respectively. The electromotor oriented the module in the east-west direction based on the principle of the chronology of the sun, and in the north-south direction, the change in the gas pressure, due to the temperature change, activated a pneumatic cylinder to rotate the module. The evaluation tests were carried out at the different modes of tracking (including east-west, north-south and double axis). The results showed that the available solar energy on the PV module increased by 5.03%, 33.75% and 38.78% using the tracker at the north-south, east-west and double axis modes, respectively. This, finally, improved electricity generation of the PV module by 4.82%, 31.43% and 36.25%, respectively. Moreover, employing the tracker system led to an increase in operating temperature of the PV module. Based on the operating temperature of the module with the tracking system, it was proposed for using in the photovoltaic-thermal collectors. The designed system could track the sun trajectory with the accuracies of 0.6% and 8% in the east-west and south-north directions, respectively.