Simulation of metastable zone width and induction time for a seeded aqueous solution of potassium sulfate

The metastable zone width (MSZW, ΔT_m) and induction time (t_ind) were determined with computer simulation for seeded batch crystallization of potassium sulfate from aqueous solution. The MSZW and induction time determined with simulation showed the same behavior as experimental values reported in the literature; log (ΔT_m) increased linearly with an increase in log R (R: cooling rate) and t_ind decreases in proportion to (ΔT)⁻ⁿ (ΔT: supercooling, n: nucleation order in the secondary rate expression of B=k_n(ΔT)ⁿ). The secondary nucleation parameters (k_n and n) were deduced both from the simulated MSZW and induction times by using the previously proposed model [J. Cryst. Growth, 2010, 312, 548–554]. The secondary nucleation rate calculated with the deduced parameters was in agreement with that calculated with the parameters input for simulation.     

Comments on “A bicriteria flowshop scheduling problem with setup times”

The aim of this paper is to point out that the integer programming model proposed by Eren and Güner [T. Eren, E. Güner, A bicriteria flowshop scheduling problem with setup times, Appl. Math. Comput. 183 (2006) 1292-1300] is incorrect. We propose a new integer programming model for the same scheduling problem based on their model.     

Dielectric Behavior of Middle Phase Microemulsion

l ntroductionMicroemulsiolls are transparent and nuid systems composed of water, oil andamphiphilic molecules. They form spontaneously with simple mixing. Microemulsionsmay be water- or oil- continuous and bicontinuous under some conditions of temperatureor composition. Middle phase microemulsions(MPME) is called the 'bicontinuousstate' which is considered to be a sponge-like random netWork. Owing to its ultralowinterfacial tellsiolls against the excess water and oil phase with which they ar…     

A note on transfer function model specification with noisy closed‐loop input data

We assume that the input in a transfer function noise model is determined by a proportional‐integral‐derivative controller that is subject to noise. We show how such a noisy feedback in the input series affects the standard Box–Jenkins method of specifying the transfer function model. Our findings have important implications for the analyst who uses the traditional Box–Jenkins approach. The analyst will be led to estimate an incorrect transfer function model if feedback (exact or noisy) is present. Copyright © 2009 John Wiley & Sons, Ltd.     

An eigenvector‐based linear reconstruction approach for time stepping in discontinuous Galerkin scheme used to solve shallow water equations

Discontinuous Galerkin (DG) methods have shown promising results for solving the two‐dimensional shallow water equations. In this paper, the classical Runge–Kutta (RK) time discretisation is replaced by the eigenvector‐based reconstruction (EVR) that allows the second‐order time accuracy to be achieved within a single time‐stepping procedure. Moreover, the EVRDG approach yields stable solutions near drying and wetting fronts, whereas the classical RKDG approach yields instabilities. The proposed EVRDG technique is compared with the original RKDG approach on various test cases with analytical solutions. The EVRDG solutions are shown to be as accurate as those obtained with the RKDG scheme. Besides, the EVRDG scheme is 1.6 times faster than the RKDG method. Simulating dambreaks involving dry beds confirms that EVRDG scheme gives correct solutions, whereas the RKDG method yields instabilities. Copyright © 2012 John Wiley & Sons, Ltd.     

两个极限的注记

利用数值积分方法给出了波利亚的名著中两个极问题的证明,并给出了两个结论更强的结果.     

工程测量中光波干涉必须满足的几个条件

讨论了两列光波发生干涉现象的理想化条件和在实验中能否观察到干涉现象发生的操作性条件，推导了各种情况下的理论公式。从工程应用的角度出发，研究了检测仪器的响应时间T和光强分辨能力对观察光的干涉现象的影响，提出了观察光的干涉现象的第四个必要条件，对在各种情况下应用光的干涉现象有一定的指导作用。     

Kinetics of the formation of Fe2B layers in gray cast iron: Effects of boron concentration and boride incubation time

The growth kinetics of Fe₂B layers formed at the surface of gray cast iron were evaluated in this study. The pack-boriding process was applied to produce the Fe₂B phase at the material surface, and the variables included three temperatures (1173, 1223 and 1273 K) and four exposure times (2, 4, 6 and 8 h). Taking into account the growth fronts obtained at the surface of the material and the mass balance equation at the Fe₂B/substrate interface, the boron diffusion coefficient on the borided phase was estimated for the range of treatment temperatures. Likewise the parabolic growth constant, the instantaneous velocity of the Fe₂B/substrate interface, and the weight gain in the borided samples were established as a function of the parameters τ(t) and α(C), which are related to the boride incubation time (t₀(T)) and boron concentration at the Fe₂B phase, respectively. Observation of the growth kinetics of the Fe₂B layers in gray cast irons suggest an optimum value of boron concentration that is in good agreement with the set of boriding experimental conditions used in this work.