A methane-air turbulent premixed flame is simulated via probability density function (pdf) and Reynolds averaged Navier-Stokes (RANS) methods. In the pdf approach, molecular mixing is modelled through the modified Curl’s model. A Monte Carlo method is used to solve the pdf transport equation. Also, the run time averaging and local time stepping procedures are incorporated to increase the accuracy and reduce the computational time of the pdf simulation. In the RANS approach, the averaged chemical reaction rate term is modeled by the eddy breakup-finite rate model. A finite difference discretization on a staggered grid is utilized to obtain the numerical solution for the RANS equations. The characteristics and differences of the two above mentioned methods, including computational time and predicted mean fields, are investigated in detail for premixed flames. It is observed that the discrepancy of the predicted mean fields between the two methods is large especially in regions near the flame. In addition, the predicted flame length by the pdf method is approximately half the flame length predicted by the RANS method.

This paper introduces a new model for predicting the tropospheric scintillation path loss with respect to Iranian climate. Tile variance, probability density function (pdf), and attenuation scintillation are predicted based on the new model and using measurement data obtained from Iranian metrological department for different parts of Iran. Applying this model and corresponding data, the variance of scintillation, scintillation pathl loss and scintillation ,standard deviation predicted for different Iranian cities. The results reveal that scintillation variance pdf shows a long normal behaviour in Iran. Moreover, the path loss due to scintillation phenomenon in satellite- ground communication links cannot be ignored particularly in microwave and higher frequency ranges. Therefore, it is necessary to take into account these effects when designing satellite- ground and microwaves communicational links.

In this study, a new method for producing initial conditions that are required for the Brownian dynamics simulation of dilute polymer suspension flows is proposed. For this purpose, the equilibrium probability distribution function is employed to generate an equilibrium ensemble of polymers. This approach is programmed and by using it, a polymer suspension in the inception of a simple shear flow is simulated. Also, the results of simulations in a similar flow configuration based on the conventional approach of generating initial conditions are presented. The excellent agreement between the results demonstrates the high accuracy of the proposed method for generating initial conditions. The main advantage of the proposed method is its low computational cost.

Background and Objectives: Marital satisfaction and compatibility of spouses are axis and focus of family foundation, which are influenced by different factors. One of these factors is occupational status of each spouse The current study was carried out with the aim of evaluating the marital satisfaction in female nurses of Khalkhal city.Methods: This research was conducted as a descriptive cross-sectional study on 120 female nurses of Khalkhal city in 2014. The sampling method was non-probabilistic convenience sampling. Data were analyzed using Kolmogorov-Smirnov, Spearman correlation coefficient, independent t-, one-way ANOVA, Friedman, and multiple liner regression tests at the significance level of p<0.05.Results: The total study population was 120 female nurses with the mean age of 34.03±6.52 years. Ninety-nine subjects (82.5%) had very high satisfaction, 14 subjects (11.7%) high satisfaction, and 7 nurse (5.8%) moderate satisfaction. There was a significant relationship between marital satisfaction and number of sex (p<0.001) and occupation of spouse (p<0.04). The predictor variables effective in marital satisfaction are related to baby number (Beta=2.64, p>0.01) and working experience (Beta=1.85, p>0.04).Conclusion: In this study, the level of marital satisfaction was reported to be high among nurses of Khalkhal. Perhaps more complete and extensive investigation could show the cause of high satisfaction among nurses. Also, identification of the factors promoting marital satisfaction could be used as a strategy to teach spouses of other trade and professional groups, in whom satisfaction level is low.

Purpose: Clustering and co-word analysis is a method to reveal relationships and links and illustrate the intellectual structure of a scientific field. This research tries to study the intellectual structure of articles in the field of futures studies in Iran by using the technique of co-word analysis. Method: The current research is a descriptive-analytical development with a scientometric approach. The statistical population is 921 articles retrieved records in the field of futures studies. Findings: The findings showed that articles in the field of futures studies in Iran are often associated with positive growth, and in terms of frequency, the keywords scenario, Islamic Republic, and foresight are the most frequent in futures studies. The findings related to the hierarchical clustering led to the formation of 8 clusters in this field, namely "ICT visions", "geographers who love the future", "knowledge development", " Futuristic higher education", "Future of Religion", "Regional Relations", "Strategic Foresight" and "Heavy Weight of Method". Conclusion: According to the findings of the current research and the high frequency of the keyword scenario, as well as the density and relationships of this keyword with other keywords, it can be concluded that the scenario is the dominant approach in futures studies. Also, according to the resulting clusters, it was observed that these researches have a high variety, but addressing the future in many areas is still neglected.

This paper proposes a novel two step modeling and analysis on the continuous random variable of electricity price. At the first step, the continuous optimal control theory is used to model and solve the maximum entropy problem for a continuous random variable. The maximum entropy principle provides a method to obtain least-biased Probability Density Function (pdf) estimation. In this paper, to find a closed form solution for the maximum entropy problem with any number of moment constraints, the entropy is considered as a functional measure and the moment constraints are considered as the state equations. Therefore, the pdf estimation problem can be reformulated as the optimal control problem. At the second step, the proposed unbiased pdf estimator is used to estimate the pdf of electricity price. Moreover, the statistical indices and the distributional characteristics of electricity price are analyzed at each load level. The simulation results on the electricity price data of New England, Ontario and Nord Pool electricity markets show the efficiency of the proposed pdf estimator. In addition, the obtained results show that by decreasing the load, the statistical and distributional characteristics of the electricity price inclined toward the statistical properties of the normal distribution.

The interaction between syntax and word-formation has been of great theoretical significance in the past four decades. The question that is now raised is as follows: is word-formation an independent module, or should it be subsumed under syntax?Considering word-formation processes in Persian, this article is an attempt to provide a number of facts in favour of the existence of an independent word-formation component. These facts are:1. A great number of complex words in Persian are headless, contrary to the syntactic phrases.2. A great number of the Persian compounds have meanings which are predictable, yet different from their compositional meanings.3. The syntactic category of a large number of the Persian compounds is different from that of their constituent words.4. The derivational suffix “-i”, while added to nouns, may make adjectives or nouns, according to which we need to devide the Persian nouns into two subgroups. But this distinction is irrelevant in syntax.5. The Persian inflectional morphemes do not occur inside compounds.6. Compounds and syntactic phrases have different stress patterns.