Distributed consensus-based algorithm for social welfare in smart grid with transmission losses

In this paper, we present a distributed consensus-based algorithm to solve the social welfare maximization problem. This is one of typical problems of distributed energy management in smart grid. In this problem, we consider not only the generator and demand, but also the transmission losses which make the feasibility set of the formulated problem a non-convex set. In solving this issue, we find a noticeable result that the primal problem has the same solution with a new convex optimization problem by getting the utmost out of the implied term in practice. Considering the general communication topology among generators and demands, we first design a finite step algorithm to make each generator and demand know the information of parameters of others.Then, we design a distributed algorithm and also prove the optimality and convergence of the proposed algorithm. Finally, the convergence and optimality are examined through extensive simulations.     

Determination of formaldehyde in fruit juice based on magnetic strong cation-exchange resin modified with 2,4-dinitrophenylhydrazine

A method was developed using magnetic strong cation-exchange resin modified with 2,4-dinitrophenylhydrazine (DNPH) for the determination of formaldehyde (HCHO) in fruit juice samples. The procedures of extraction and derivatization were carried out in a single step by stirring the resins and diluted fruit juice with water. When the procedures were completed, the resins adsorbing the HCHO-DNPH derivative were easily separated from the sample matrix by an adscititious magnet. The HCHO-DNPH derivative eluted from the resins was directly determined by high-performance liquid chromatography with UV detector at 360 nm. The limit of detection of the proposed method in fruit juice obtained is 6.0 ng mL⁻¹. In this work, the volume of fruit juice was 5 mL and the amount of MSCX resins was 100 mg, and the resins can be reused 10 times. The relative standard deviations of intra-day and inter-day ranging from 3.9% to 6.1% and from 4.2% to 7.0% are obtained, respectively. The recovery of HCHO in the analysis of spiked fruit juice samples is in the range of 85.7-100.4%.