Modeling the Proposal of the Simultaneous Purchases and Sales of Electricity and Gas for the Energy Market in a Microgrid Using the Harmony Search Algorithm

The use of different energy carriers together,known as an energy hub,has been a hot topic of research in recent years amongst scientists and researchers.The term energy hub refers to the simultaneous operation of various infrastructures for energy generation and transfer,which has gained momentum in the form of microgrids(MGs).This paper introduces a new strategy for the optimal performance of an MG consisting of different energy carriers for each day.In a smart distribution network(DN),MGs can reduce their own costs in the previous-day market by bidding on sales and purchases.The sales and purchases bidding problem is challenging due to different uncertainties,however.This paper proposes a two-stage strategy for making an optimal bid on electricity sales and purchases with electricity and gas price dependency in the previous-day and real-time markets for an energy hub.In this model,the MG behavior regarding the electricity and gas energy sales/purchase,the simultaneous effects of electricity and gas prices,as well as the energy carriers’dependence on one another are all examined.Due to the inherent uncertainty in the sources of clean energy production,the probabilistic model and the production and reduction scenario have been used in the paper to cover this issue.In the proposed grid,energy sales/purchases are presented in a multi-carrier MG in a two-stage model.This model is solved by using the harmony search algorithm in MATLAB.Numeric results demonstrate the benefits of this model in reducing energy hub costs of operation.

Prediction Research on Ride Comfort of Special Full Trailer used by Precision Equipment

In order to evaluate a full trailer’s vibration performance,lumped mass model of seven degrees of freedom is set up to predict the ride comfort of whole vehicle.The acceleration history and the transfer function of each measuring point can be got from simulation.The analysis results show that the maximum acceleration RMS value of the vehicle mass center is about 0.3g,which satisfies the requirements of attenuating vibration of precision equipment being transported on particular roads and speeds.So the research provides valuable reference for the optimum selection of the suspension system’s parameters.

Influence of Coal Gangue Aggregate Grading on Strength Properties of Concrete

This paper investigates the feasibility of using coal gangue as coarse and fine aggregates in concrete as well as how the coal gangue aggregate grading affects concrete properties. Nine mixed concrete samples were prepared with the value n in Fuller＇s curve ranged from 0.44 to 0.68. The coal gangue aggregate with n = 0.62 shows the highest density, water absorption, cylinder strength and the lowest voids. The results indicate that using coal gangue as coarse and fine aggregate in concrete is tech- nically feasible and useful. When n is 0.62, the values of the slump, 28-day compressive, splitting tensile strength, flexural strength and elasticity modulus of coal gangue concrete reach the highest. The highest 7-day and 28-day compressive strength were 24 MPa and 37 MPa in mix CG7, respectively. It is possible to produce grade 30 coal gangue concrete with coal gangue coarse and fine aggregate.

Properties of Steel Fiber Reinforced Coal Gangue Coarse Aggregate Concrete

In this paper,workability,strength and durability of coal gangue coarse aggregate concrete with different steel fiber content levels have been studied.The results indicate that the concrete compressive strength,flexural strength and tensile splitting strength at the age of 28 days increase with the steel fiber content increasing,while cost and impermeability reduce with steel fiber content increasing.Based on the data of the workability of fresh concrete,mechanical properties and durability of hardened concrete,the concrete cost index system are established to evaluate and optimize the steel fiber content in coal gangue concrete by Efficacy Coefficient Method.The optimization result reveals that the maximum value of the system efficacy coefficient is up to0.87,the coal gangue concrete with steel fiber 1.5%（V︰V）performs better.