Selection of sustainable suppliers in the oil and gas industry using fuzzy multi-criteria decision-making methods

Due to the globalization of competition in various fields, suppliers must have the best performance by creating different competitive advantages. In addition, the oil and gas industry has lots of sustainability issues in the supply phase. Accordingly, this study provides a comprehensive framework for ranking and selecting sustainable suppliers in the oil and gas industry. In this research, first, using the fuzzy analytical network process method, the indicators of selecting stable suppliers are ranked. Next, by applying the Electre method, the most appropriate suppliers are chosen. Numerical results show that the quality indicators of materials purchased from suppliers and commitment to contracts were ranked first and second among all criteria. Moreover, the efficiency of the proposed framework is approved by comparing with the real-world situation

A critique of effectiveness concept for heat exchangers; theoretical-experimental study

In this study attempts are made to clarify some hidden features of effectiveness concept (the ratio of ac- tual heat transfer to maximum possible heat transfer) of heat exchangers and provide a critique viewpoint and comprehensive description about that. It is shown in present paper that the effectiveness parame- ter requires much more attention when it is used in fluid-flow parametric or sensitivity studies of heat exchangers and lack of consideration of its hidden features may lead to incorrect or imperfect decision- makings on curve behavior of effectiveness. Indeed, it is shown that the curve trend of effectiveness against the Reynolds number of one side of heat exchanger can be ascending, descending, or ascending- descending depending on the mass flow rate ( Re number) of the other side fluid. Although this critique viewpoint is not considered as a weakness of the effectiveness definition for heat exchangers, inattention may lead to wrong or imperfect inferences in sensitivity analysis of effectiveness parameter. Moreover, it is not logical to provide empirical correlation for effectiveness against flow parameters without the con- sideration of described features of effectiveness in this study. In order to support the described viewpoint some experiments are performed on double helical tube heat exchanger to evaluate the related thermal parameters and describe the mentioned features of effectiveness statistically. However, the provided anal- ysis is valid for any other type heat exchanger as well.Shu-Rong Yan, Hazim Moria, Samira Pourhedayat, Mehran Hashemian, Soheil Asaadi, Hamed Sadighi Dizaji, Kittisak Jermsittiparser

A Secured Social-Economic Framework Based on PEM-Blockchain for Optimal Scheduling of Reconfigurable Interconnected Microgrids

Optimal scheduling of reconfigurable interconnected microgrids is a precious and critical task for the residential consumers especially with the integration of renewable energy sources, dispatchable units and energy storage systems. In this regard, not only the optimal scheduling of the microgrids in a realistic and correlated environment is a necessity, but also the guarantied security and the prevention of cyber-attacks are mandatory tasks for the operators. This article first addresses these issues by developing a novel framework based on blockchain for secured data transaction from the individual microgrids’ components to the central control unit and then tries to find the optimal scheduling plan using stochastic programming based on point estimate method (PEM). Through such a hybrid PEM-blockchain based framework, the interconnected microgrids can supply the residential loads in a fully reliable, economic and secured structure. We also consider a social-economic framework to not only minimize the total operating cost of the microgrids, but also benefit the customers by enhancing the social factors through the optimal switching. Considering the complex and nonlinear nature of the problem, an effective corrected crow search (CCS) algorithm is deployed to find the most optimal operating point for the microgrids. The quality and capabilities of the proposed model are investigated using a practical residential interconnected microgrid. The results show that the optimal switching could reduce the total operation cost from $22,716 to $21,935 (3.56% reduction). Also, the average energy not supplied (AENS) has reduced from 1.4115 to 1.352 kWh/customer.yr (4.40% reduction), which are notable values. The results advocate the quality and functionality of the proposed framework