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Family, as a social institution or group, has been evolving throughout history. Evolution of family needs to be studied in order to understand its functions and structure. Unfortunately, the evolution of family during the long Iranian history has not been studied seriously. This paper is an effort to shed some light on the structure and functions of the Iranian family under Sassanids using documentary method. The findings reveal that the dominant form the family in this period was “extended family” which along with the religious and political institutions constructed the Sassanid society. The family structure in this era was patriarchal, polygamy was prevalent, and in-group marriages were preferred. The official religion of the empire, Zoroastrianism, viewed family as a sacred institution with its main function as reproduction. Other functions of the family were production and provision of economic support, socialization and education of offsprings, who had to inherit their father and mother’s jobs. Relatives of father, in this period, had superiority to the relatives of mother’s side, and the oldest son and his family lived with his parents.

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After the change in the basis of government's legitimacy from divine right of monarchs to people's or nation's right to sovereignty in European's Political Philosophy, “Separation of Powers” has been raised as the basic principle of government by scholars and philosophers of politics. Later it leads to the birth of the term “Executive Power” in the legal-political literature. This term has encountered several changes in practical arena and has undergone many implications in different circumstances and eras. In this article, besides reviewing the nature of “Executive Power” from the attitude of the originators of the “Separation of Powers” theory, its bases and main tasks are analyzed, and by employing these study's results, the current approaches, i.e. classical/traditional and modern approaches are evaluated toward interpretation of the concept of “Executive Power”. Finally, highlighting the modern approach, which believes in extensive interpretation of this concept according to its possible purposes and main tasks, we emphasized that it is essential for parliament to appropriately supervise on the executive power to prevent it from derogation, not limiting it, which may decrease its efficiency.

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The electrohydraulic valves are commonly used in the engineering applications. These valves, as the medium elements, prepare the hydraulic systems for the electrical control applications. For the precise performance of these valves, disturbances in the valve elements dynamics will disturb the control process of the system. The electrohydraulic servo valves are greatly affected by the external acceleration, for instance in the aerospace applications. In a two stage flapper- nozzle electrohydraulic valve, the external acceleration changes the pressure of the fluid leaving the nozzles and it affects the flapper and spool of the valve like a virtual force. Thus, when the applied current is zero, the acceleration diverts the spool of the valve from the equilibrium point, and unwanted performance in the valve occurs. In this study the pilot pressures of the spool is modeled in unsteady state condition. The effects of the acceleration on the flapper and the spool of the two stage electrohydraulic valve are investigated. At the end, the obtained model is verified by use of the experimental data.

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In this paper motion of some blood clots with different mechanical properties in the cerebrovascular arteries is investigated. Blood clots mostly are originated from heart or other cardiovascular arteries and by entering the cerebrovascular arteries trigger occlusion and deprive the brain’s tissue from proper perfusion. To study this phenomenon, we used a patient-specific geometry of cerebrovascular arteries and due to obtain the motion of clot and blood’s flow in cerebral arteries, algorithm of fluid-structure interactions was used. Although previous researches have not considered the effect of mechanical properties on the motion of clot, our results demonstrate the variation of the dynamic parameters of the clot’s motion by changing the mechanical properties. We show that by increasing the rigidity of the clot, their tendency for entering to the larger arteries is raised. Also other dynamic parameters like clot’s average velocity altered when the mechanical property of the clots changes. Mechanical parameters have the main role in the motion of clots and by investigating them, our sight to the mechanism of pathologies would expand, moreover, strategies of the cerebrovascular treatments would be fascinated in the future.

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Refrigerant is one of the most important parts in a refrigeration cycle. In many refrigeration cycles, especially in the natural gas processing industry, propane is used as refrigerant due to its desirable thermodynamic properties. There are two ways for transferring propane and butane gases from extraction point to the consumption site: a) Pipeline and b) liquefaction and transport in liquid form. The most profitable method for transporting large quantities of propane and butane gases is liquefaction and transport in liquid form using storage tanks. Liquefaction at atmospheric pressure is the most common method for transporting large quantities of gases using specifically designed refrigerated ships. In this paper, a gas refinery butane and propane liquefaction cycle is described first and then simulated in HYSYS software. Afterwards, Genetic Algorithm is used to minimize the total power consumption of the liquefaction cycle, through connecting HYSYS and MATLAB softwares. There are 13 variables and 13 constraints for compressors and heat exchangers in the formulation of the optimization problem. The results of this constrained optimization problem show that the power consumption can be reduced by 12.49% compared to the base case.

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According to the high tomato loss in Iran, the aim of the present study was to introduce Iranian endemic gums including tragacanth, locust bean and Alyssum homolocarpum seed gums for coating this fruit and also to investigate and compare their functional properties. The results showed that the solution of Alyssum homolocarpum seed gum had the highest wettability (-22.92 mN/m) on the fruits surface following by tragacanth gum (-43.23 mN/m) and locust bean gum (-22.92 mN/m). Moreover, the tragacanth and Alyssum homolocarpum seed gums showed the highest and the lowest apparent viscosities respectively. Investigating the physical features of the films revealed that tragacanth gum and locust bean gum had the ability to form transparent and flexible film; while, Alyssum homolocarpum seed gum film was more opaque and had a greenish hue with less flexibility. The water vapor permeability of tragacanth and locust bean gum films was significantly higher than that of Alyssum homolocarpum seed gum film (P<0.05). According to the results, it can be concluded that although Alyssum homolocarpum seed gum film had higher wettability on the surface of tomato, locust bean gum and tragacanth gum were more appropriate choices for tomato coating due to the higher transparency, apparent viscosity, water vapour inhibition and solubility in water.

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Solid lipid nanoparticles (SLN) are one of the appropriate delivery systems which attract enormous interest for encapsulating bioactive componds in recent years. One of the important physicochemical properties of SLNs is particle size that is influenced by formulation and production process parameters. Inappropriate conditions of the nanaocarrier production process in the pre and main emulsion steps cause unsuitable paricle size as well as unstable emulsion and gel formation. Therefore, in this research production process of SLN was investigated and optimized by hot homogenization method and with two lipids of Compritol and Precirol separately. Hence, homogenization time in preparation of pre emulsion and amplitude and time of ultrasonication in final emulsion production was studied to obtained the smallest particle size. In pre emulsion step, the smallest particle size for Compritol SLN (619±4 nm) and Precirol SLN (373±3 nm) obtained in 180 second mixing by ultra-turax in 16000 (rpm). In final emulsion, 40% amplitude and 3 minutes caused to attained smallest particle size in Compritol SLN (397±5 nm) and Precirol SLN (259±2 nm). Then polydispersity index (PDI), zeta potential and visual observation of nanocarriers with optimized particle size were examined. The results showed that Precirol SLN had higher zata potential (-12.3±0.6 mV) than Compritol SLN (-8.97±0.17mV) but PDI of two nanocarriers was not significantly different. Visual observation of both nanocarriers at the storage time showed no instability. 

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place, In addition to the physical dimensions also has spiritual and emotional aspects and encourages emotional sense in its residents. Due to these feelings, a kind of attachment to place, leading people to form a local identity created which are mainly proposed in the inner city.
This sense of attachment to the place on social inclusion with a focus on social capital and capacity of the place emphasis on the quality of the living environment, which affects on analysis process, it is the purpose of this article, and aims to introduce the use of structured models (multi-dimensional because of the research size and latent variables) in the field of urban studies.
In this, correlation analysis study, a sample of 475 of the teenagers from the communities of districts 17, 10, 8 and 1 of Tehran were selected, through stratified systematic sampling, and each of the five research variables, include social inclusion, capacity, location, social security, access to services and socio-economic origin using "structural equation modeling" techniques "path analysis" were examined; then three different models of the relationships between variables provided that the model results show a sense of attachment to place among adolescents by variables influencing spatial capacity and better access to services than the rest of the relationship explanation stems.