Introduction Monitoring and prediction of hydrologic droughts and determining the onset and duration of drought spells have an important role in water resources management and planning to reduce the adverse effects of drought. In the present study the characteristics of hydrological drought in daily discharge time series from 20 hydrometric stations in Golestan Province have been analyzed. Matherials & Methods: In this study, the onset and end of drought periods, mean discharge, effective discharge and threshold level were calculated and then sequence number of 1 to 30-month durations were determined. According to the results of Power Laws Analysis, the intensity and duration patterns of hydrological drought periods were distinguished. The results specified an inverse relationship between the intensity and duration of wet and dry spells. The highest severity of dry spell is related to Nodeh station (Line slope=-0. 26) and the highest intensity of wet spell was observed in Ramian station (Line slope =-0. 28) which indicated the stability of dry and wet river flow regimes in Nodeh and Ramian stations. Also, the longest durations of dry and wet periods were determined for the Aghghala (32. 89) and Basirabad (16. 29) stations, respectively, which represents the average maximum probable durations. Discussion of Results & Conclusions: The proximity, closeness to a straight line or parallel lines without intersection proved the homogeneity regime of wet-dry spells in the Gorganroud watershed. Analysis of wet-dry spells using the Power Laws technique provides a basis to determine the flow regime, severity and duration of hydrological drought.

In this paper, a novel risk-based, two-objective (technical and economical) optimal reactive Power dispatch method in a wind-integrated Power system is proposed which is more consistent with operational criteria.  The technical objective includes the minimization of the new voltage instability risk index. The economical objective includes cost minimization of reactive Power generation and active Power loss. The proposed voltage instability risk employs a hybrid possibilistic (Delphi-Fuzzy)-probabilistic approach that takes into consideration the operator’s experience, the wind speed and demand forecast uncertainties when quantifying the risk index. The decision variables are the reactive Power resources of the system. To solve the problem, the modified multi-objective particle swarm optimization algorithm with sine and cosine acceleration coefficients is utilized. The method is implemented on the modified IEEE 30-bus system. The proposed method is compared with those in the previously published literature, and the results confirm that the proposed risk index is better at estimating the voltage instability risk of the system, especially in cases with severe impact and low probability. In addition, according to the simulation results compared to typical security-based planning, the proposed risk-based planning may increase the security and economy of the system due to better utilization of system resources.

In this paper, a new method for extending and relaxing the noise-coupling (NC) technique is proposed to enhance the noise-shaping order without adding the number of integrators. The noise-shaping order of the introduced ∑∆ modulator whit applying a second-order noise-coupling technique is enhanced and its performance with optimizing the noise transfer function (NTF) zeros is improved. Also, by removing the analog adder at feedforward path and transferring it to a new feedback branch before the last integrator and adding second-order NC path can be decreased the input voltage swing to the quantizer. Thus, by improving the modulator resolution, Power consumption can be reduced. Mathematical analyses and behavioural simulation results confirm the effectiveness of the new NC method. To examine its performance, a 2nd-order single loop ΣΔ modulator was designed. The new noise-coupling method is used to achieve the three-order noise shaping to increase the resolution with low complexity and low-Power. The results show an outstanding improvement in signal-to-noise and distortion ratio (SNDR) compared to the conventional structure.

Purpose: The flourishing of political parties and currents is one of the signs of the degree of development in societies. In contemporary Iran and since the formation of the constitutional movement, political currents have gone through many ups and downs and it can be said that political currents in Iran after the Islamic Revolution have not yet reached the stage of institutionalization and stability. A characteristic feature of political currents in Iran is the divergence and division among political currents in recent decades, and this can be one of the reasons for the instability and cross-sectional and seasonal activity of political parties in Iran. Therefore, the necessity of leading research seeks to answer the question of how factors and divergence among political currents in Iran after the victory of the Islamic Revolution can be analyzed? And what are the scenarios for the advancement of political currents in Iran?Method: To answer this question, the method of causal-layer Analysis, which is one of the qualitative methods in futures research, has been used.Findings: The research findings indicate that this divergence is due to a wide range of reasons from the level of causal systems (from the institutionalization of Power to the formation of parties as elitist initiatives), worldview and discourse (from charismatic political authority to culture). Subsidiary-follower politics to myth-metaphor (Iranian individualism to belief in a strong state-weak society) can be analyzed.Conclusions: Three scenarios for the future of Iranian political currents can be considered: integration of currents as the security valve of the political system, the collapse of political currents in the traditional form, integration and consolidation in new social movements (virtualized parties).

In today's world, Power is more persistent and invisible than traditional Power systems. In the past it was thought that Power works only in the political sphere, and it has been negative and oppressive. Foucault believes that this conception of Power conceals its actual performance because systems of Power are not only negative and oppressive. In this study, the social bases of brand Power and market structure components corresponding to the primary Power base are explained. Power relations are strategic games between individuals, despite the influence of Power on individuals, they can subdue domineering. According to Foucault, the aim of Power is influencing on human choices and shaping his actions. So consumers resist against the Power of producers. And, according to Foucault, domineering Powers are subdued and involved as part of the network of Power as the dominated. Power on the market, as a network of manufacturers, buyers, distributors and consumers of final goods or process merchandise, the capillary network influence anywhere, and people always live in a dual situation.

Exergy Analysis is based on combined first and second laws of thermodynamics and is a useful tool to analyze the energy systems in a better and more realistic way than an energy Analysis, based on the first law of thermodynamics. Combination of exergy from thermodynamics with conventional concepts from engineering economy which is referred to as thermo-economy (exergo-economy) is a valuable tool to analyze the energy systems in a better way. In this paper, efforts are made to apply the concept of thermo-economy to analyze two Power cycles (a combined Gas and Steam cycle and a conventional steam Power plant). In this Analysis, the results of an exergy calculation are combined with the economic aspects such as investment costs, fuel costs, and also operation and maintenance costs. The goal of this study is to show how to implement the concept of thermo-economy to these cycles and also how to estimate the price of the product (electric Power generated). Assessment of the components exergy destruction costs is a second objective in this study. Results obtained from this Analysis clearly show the effect of the cost breakdown and the component performance on the price of the final product. Comparison of the price of the product in these cycles shows that the combined cycle is superior to the conventional steam Power plant.