Design of a Proportional-Integral-Derivative Controller for an Automatic Generation Control of Multi-area Power Thermal Systems Using Firefly Algorithm

Essentially, it is significant to supply the consumer with reliable and sufficient power. Since, power quality is measured by the consistency in frequency and power flow between control areas. Thus, in a power system operation and control,automatic generation control(AGC) plays a crucial role. In this paper, multi-area(Five areas: area 1, area 2, area 3, area 4 and area 5) reheat thermal power systems are considered with proportional-integral-derivative(PID) controller as a supplementary controller. Each area in the investigated power system is equipped with appropriate governor unit, turbine with reheater unit, generator and speed regulator unit. The PID controller parameters are optimized by considering nature bio-inspired firefly algorithm(FFA). The experimental results demonstrated the comparison of the proposed system performance(FFA-PID)with optimized PID controller based genetic algorithm(GAPID) and particle swarm optimization(PSO) technique(PSOPID) for the same investigated power system. The results proved the efficiency of employing the integral time absolute error(ITAE) cost function with one percent step load perturbation(1 % SLP) in area 1. The proposed system based FFA achieved the least settling time compared to using the GA or the PSO algorithms, while, it attained good results with respect to the peak overshoot/undershoot. In addition, the FFA performance is improved with the increased number of iterations which outperformed the other optimization algorithms based controller.

Calculation of Intercepted Volume of Sewer Overflows: a Model for Control of Nonpoint Pollution Sources in Urban Areas

The authors discovered large differences in the characteristics of overflows by the calculation of 1) intercepting volume of overflows for sewer systems using SWMM model which takes into consideration the runoff and pollutants from rainfalls and 2) the intercepted volume in the total flow at an investigation site. The intercepting rate at the investigation point of CSOs showed higher values than the SSDs. Based on the modeling of the receiving water quality after calculating the intercepting amount of overflows by considering the characteristics of outflows for a proper management of the overflow of sewer systems with rainfalls, it is clear that the BOD decreased by 82[KG-*3].9%-94.0% for the discharge after intercepting a specific amount of flows compared to the discharge from unprocessed overflows.

Hot Forging of Nitrogen Alloyed Duplex Stainless Steels

因为需要论坛，双不锈钢高正在获得全球重要性这的抵抗 material.Three 作文组织的力量腐蚀是选择 withthree 不同的氮内容 viz ， 0.15 wt %(合金 1 )， 0.23 wt %(合金 2 )和 0.32 wt %( alloy3 ) .The 钢在一个高频率正式就职炉子被融化并且热从16%～62% .In 前进了到 variousreductions 这个工作，在 ferritecontent 上的热前进的效果，坚硬，收益力量。

Nonlinear Mixed-Effects Models for Repairable Systems Reliability

Mixed-effects models,also called random-effects models,are a regression type of analysis which enables the analyst to not only describe the trend over time within each subject,but also to describe the variation among different subjects.Nonlinear mixed-effects models provide a powerful and flexible tool for handling the unbalanced count data.In this paper,nonlinear mixed-effects models are used to analyze the failure data from a repairable system with multiple copies.By using this type of models,statistical inferences about the population and all copies can be made when accounting for copy-to-copy variance.Results of fitting nonlinear mixed-effects models to nine failure-data sets show that the nonlinear mixed-effects models provide a useful tool for analyzing the failure data from multi-copy repairable systems.

Spin-up and Spin-Down Times of Rotational Air Flow Depended on Mean Air Velocity and Surface Roughness on Inner Surface in Cylindrical Vortex Chamber

The spin-up time TA in the spin-up process and spin-down time TD in the spin-down process of rotational air flow in the cylindrical vortex chamber with three kinds of the artificial surface roughness were investigated. One of the most different characteristics between the smooth and rough surface conditions was the spin-down time TD. Also the transient response of the tangential velocity on the spin-up process was analyzed numerically and this result was compared with the experimental results. The above stated results are reported here in detail.

Magnetohydrodynamic(MHD)boundary layer heat and mass transfer characteristics of nanofluid over a vertical cone under convective boundary condition

This paper investigates the boundary layer flow,heat and mass transfercharacteristics over a vertical cone filled with nanofluid saturated porous medium with theinfluence of magnetic field,thermal radiation and first order chemical reaction subject to theconvective boundary condition.Similarity transformation technique is used for the purpose ofconverting non-linear partial differential equations into the system of complex ordinarydifferential equations.The computational Finite element method has been employed to solvethe flow,heat and mass transfer equations together with boundary conditions.The impact ofvarious pertinent parameters on hydrodynamic,thermal and solutal boundary layers isinvestigated and the results are displayed graphically.Furthermore,the values of local skin-friction coefficient,rate of temperature and rate of concentration is also calculated and theresults are presented graphically.The comparisons with previously published work is made andfound good agreement.The thickness of thermal boundary layer is increased with increase inthe values of Brownian motion parameter(Nb)and thermophoresis parameter(Ni).

Conjugated polymer crystals via topochemical polymerization

The discovery and development of conductive polymers in the 1970s by Alan J.Heeger,Alan G.MacDiarmid and Hideki Shirakawa opens the new research field of organic electronics.Over the past decades,conjugated polymers and their applications in various electronic and optoelectronic devices have received considerable attention and studies due to their unique advantages of low cost fabrication methods and mechanical flexibility[1].