Electricity restructuring [Business Scene]

The Islamic Republic of Iran currently manages an electricity sector with about 40,000 MW of installed capacity, which serves more than 13 million end users through a 36,000-km high-voltage transmission interconnected grid and a more than 50,000-km medium-voltage distribution network. This fairly large power system with an annual peak demand growth rate of about 10%, one of the highest rates in the world, makes the movement toward restructuring the electricity industry of Iran unavoidable, mainly for two reasons: 1) it is expected that the restructuring and consequently the privatization would improve the performance and efficiency of the present industry 2) it is expected that the development of a new competitive paradigm in the electricity industry could make the sector more attractive for potential independent investors. Based on these ideas, the restructuring studies primarily were begun in early 1990. The studies had two main directions: providing legal foundations and determining the main implementation steps. This article discusses these two directions     

An investigation on the effects of equal channel angular pressing on the mixed‐mode fracture toughness and mechanical properties of 6063 aluminium alloy

In this study, effects of equal channel angular pressing (ECAP) on the mixed‐mode fracture toughness of Al‐6063 were investigated. The ECAP process continued up to 5 passes without failure. Grain refinement was obvious after 5 passes of the ECAP process. The average grain size reduced from 45μm to less than 1μm, and textural studies shows aligning the grains in known directions. After 4 passes, yield and ultimate strengths increase respectively from 100 and 209 MPa to 300 and 375 MPa and reduction in elongation was also observed. The microhardness improved after the process. The fracture toughness for different orientations was measured. For pure mode I (opening mode), its value decreased after the first pass from 18.4 to 15.71  ; however, it increased to about 18.8  after the fifth pass. For mixed‐mode loading condition, different orientations were investigated. The results revealed different fracture toughness reductions after the first passes of the process for specimens with different orientations. The fracture surfaces were studied by using scanning electron microscope, and refined equiaxed dimples were observed after the ECAP process.     

A markov model for investigating the impact of IEEE802.15.4 MAC layer parameters and number of clusters on the performance of wireless sensor networks

Wireless Networks - In this paper, a new analytical model is presented for cluster-based sensor networks using the non-beacon-enabled mode of IEEE802.15.4 MAC protocol. To accurately investigate...     

A hybrid optimization approach for distribution capacitor allocation considering varying load conditions

This work presents a new algorithm based on a combination of fuzzy (FUZ), Forward Update (FWD), and Genetic Algorithm (GA) approaches for capacitor allocation in distribution feeders. The problem formulation considers three distinct objectives related to total cost of energy loss and total cost of capacitors including the purchase and installation costs and one term related to total cost of produced power under peak load condition. The novel formulation is a multi-objective and non-differentiable optimization problem. The proposed methodology of this article uses an iterative optimization technique based on Forward Update approach which is embedded in a Genetic Algorithm framework. The fuzzy reasoning supported by the fuzzy set theory is used for sitting of capacitors and the GA is employed for finding the optimum shape of membership functions. The proposed method has been implemented in a software package and its effectiveness has been verified through a 9-bus radial distribution feeder along with a 34-bus radial distribution feeder for the sake of conclusions supports. A comparison has been done among the proposed method of this paper and similar methods in other research works that shows the effectiveness of the proposed method of this paper for solving optimum capacitor planning problem.     

Effect of compression point load on the path and life of fatigue crack growth in mixed mode loading

In this study, fatigue crack growth of edge crack in plate made from 5083 aluminum alloy under mixed mode fracture was numerically investigated. Effect of various parameters include initial crack direction angle (30°, 60°, 90°), initial crack length (20 and 25 mm) and load ratio (R=0 and 0.25) were considered. We also consider the effect of point compression load on crack growth life with 20 mm initial crack length under 30°, 60°, 90° at various parts of crack growth path. Mentioned models were simulated using the finite element softwares, ABAQUS and FRANC2D and their results were compared together. For validation we compare the numerical results for a specimen with its experimental data. Numerical results show good agreement with the experimental data for fracture path. It is observed that the point compression load can affect the path and life of crack growth in fatigue loading. If this load was applied in the first cycles of crack growth, its effect is more than another cases. For instance in the crack growth with initial angle 30o applying point load in 5, 10 and 15 mm of crack growth length, increase the life 79.4%, 18.9% and 6.2% respectively.     

Optimal design of multi-response experiments using semi-definite programming

Optimal design of multi-response experiments for estimating the parameters of multi-response linear models is a challenging problem. The main drawback of the existing algorithms is that they require the solution of many optimization problems in the process of generating an optimal design that involve cumbersome manual operations. Furthermore, all the existing methods generate approximate design and no method for multi-response n-exact design has been cited in the literature. This paper presents a unified formulation for multi-response optimal design problem using Semi-Definite Programming (SDP) that can generate D-, A- and E-optimal designs. The proposed method alleviates the difficulties associated with the existing methods. It solves a one-shot optimization model whose solution selects the optimal design points among all possible points in the design space. We generate both approximate and n-exact designs for multi-response models by solving SDP models with integer variables. Another advantage of the proposed method lies in the amount of computation time taken to generate an optimal design for multi-response models. Several test problems have been solved using an existing interior-point based SDP solver. Numerical results show the potentials and efficiency of the proposed formulation as compared with those of other existing methods. The robustness of the generated designs with respect to the variance-covariance matrix is also investigated.     

Inhibition of mild steel corrosion in sulfuric acid by some newly synthesized organic compounds

The corrosion inhibition of mild steel in 0.5 M sulfuric acid solutions by some new synthesized organic compounds namely (E)-2-acetyl-3-(butyl amino)-N-phenyl buten-2-thioamide (compound A), (E)-3-(4-(dimethyl amino) phenyl amino)-2-acetyl-N-phenyl buten-2-thioamide (compound B) and (E)-3-(2,3-dimethyl phenyl amino)-2-acetyl-N-phenyl buten-2-thioamide (compound C) was investigated using weight loss and potentiostatic polarization techniques. These measurements reveal that the inhibition efficiency obtained by these compounds increased by increasing their concentration. The inhibition efficiency follows the order A > B > C. Polarization studies show that these compounds are of the mixed-type but dominantly act as an anodic inhibitors for steel in 0.5 M H₂SO₄ solutions. These inhibitors function through adsorption following Langmuir isotherm. Activation energy and Gibbs free energy for adsorption of inhibitors are calculated. Molecular modeling has been conducted to correlate the corrosion inhibition properties with the calculated quantum chemical parameters.     

Designing and calibrating an agent-based platform to evaluate the effect of climate variables on residential water demand

Many Iranian metropolises, including Shiraz, are situated in arid and semi-arid regions, lacking sufficient renewable water resources. In recent years, climate changes, including drought and rising temperatures, have led to changes in water supply and demand. Given the necessity and importance of urban water supply, this study investigates the impact of different climate scenarios on residential water demand. Many studies, in their models, do not consider the social interactions between household water consumers and the change in their consumption behaviour, which serves as a fundamental drawback. Thus, the present research attempts to propose an agent-based framework by modelling social interactions via the diffusion process to investigate water consumption behaviour efficiently. The model is calibrated and applied to Shiraz City in Iran, according to the data from 2006 to 2019, and it is used to simulate each scenario for the following years until 2032. The findings show that temperature has a positive and significant effect on residential water consumption; yet, rainfall negatively affects water consumption. The simulation results of these scenarios for temperature increase or decrease and rainfall changes are estimated. In addition, the developed agent-based platform can be easily calibrated and adjusted based on the data of any other city to simulate water demand estimation under different climatic and even economic scenarios. Urban water managers can benefit from such estimates to plan future infrastructure development and proactive management of seasonal water resources under the growing pressure of potential climate change because construing the sensitivity of seasonal water consumption to climate conditions is essential to respond to variations in demand.