The effects of gating system and pattern geometry on the metal flow in the lost foam casting ((LFC)) process have been investigated using glass covered mold and video recording system. Unlike convectional casting process, the type of the gating system showed little effect on fillability in lost foam, but pattern thickness had large effect on mold filling. The mold filling behavior seems to be Controlled by the combined influences of heat and mass transfer. The flow rate increased with increasing pattern thickness.

In the integrated electrical systems, frequency Control service considering the electric vehicle (EV) aggregators could lead to time-varying delay in load frequency Control ((LFC)) schemes. These delays influence the (LFC) system efficiency, and in some situations, the lack of a clear choice of a Control strategy considering the time-varying delays causes power system instability. Thus, this paper illustrates different time-varying delays based on the stability of an (LFC) system in the EV aggregators presence. The (LFC)'s delay-dependent stability study is executed for finding the stability region and, stability criteria is suggested using the linear matrix inequality (LMI) method and Lyapunov-Krasovskii theory. Also, Wirtinger-based improved inequality and bounding lemma are applied to compute the greatest allowable delay in the (LFC) system, including the EV aggregators.

A common method for Controlling a group of parallel converters in decentralized Control strategy structure in an island microgrid, the use is the droop-down characteristics of frequency ω-P and voltage E-Q. However, the problem with using this method is that the reactive power is not properly distributed (in proportion to the capacity of the micronutrients) between the micronutrients, which may lead to overload in the converters. Microgrids may also suffer from dynamic stability problems such as power fluctuations, which can be increased by switching between active and reactive power Control. To avoid this problem, the X / R ratio of transmission lines is an important parameter that should be carefully considered in the design of micronutrient Controllers. By linearizing and simplifying conditions, the Control system conversion function model becomes a single input-single output system, which is efficient enough to show the relationship between Control parameters such as slope of droop characteristics and derivative sentences, virtual impedance, and voltage Controllers. Using this model, stability conditions for different parameters are analyzed. Also, to improve power distribution stability, common droop strategies are modified by adjusting the slope as well as adding nonlinear sentence sections. This approach reduces the coupling between active and reactive power Control and reduces the dependence of power distribution on grid parameters such as the X / R ratio. To evaluate the reliability of the proposed model, the simulation results in a sample island microgrid in MATLAB software are presented.

This paper presents a new load frequency Control ((LFC)) design in a multi area power system by using local observers. Firstly, sliding mode observers with unknown inputs are designed for each area to estimate the state variables locally. In this stage interconnections and load variations are assumed as unknown inputs. Then, local state feedback and output integral are used to attenuate the effect of load variations in each area. Analysis and simulation results for a three-area interconnected power system show improvements on closed loop performance in comparisons with other existing methods.

The effects of gating systems, number of runner, and their locations, in the Lost Foam Casting ((LFC)) of Aluminum alloy (A.413.0) were investigated. Six different gating systems, with one or two running systems were designed. X-ray radiography and the three axis-bending tests have been employed to evaluate the casting soundness and quality. The results revealed that gating systems have a major effect on the formation of the casting defects, i.e. the bottom gated produced the lowest porosity and folded, in comparison with the side and the top gated systems respectively. The number of runners, which is the melt filling entrance to the mold, can either eliminate or reduce the casting defects, whilst the increased number of runners with the reduced surface area can increase the formation of the defects.