Biodegradation kinetics of benzene,methyl tert‐butyl ether,and toluene as a substrate under various substrate concentrations

Owing to the complexity of conventional methods and shortcomings in determining kinetic parameters, a convenient approach using the nonlinear regression analysis of Monod or Haldane type nonlinear equations is presented. This method has been proven to provide accurate estimates of kinetic parameters. The major work in this study consisted of the testing of aromatic compound‐degrading cultures in batch experiments for the biodegradation of benzene, methyl tert‐butyl ether (MTBE), and toluene. Additionally, batch growth data of three pure cultures (i.e., Pseudomonas aeruginosa YAMT421, Ralstonia sp. YABE411 and Pseudomonas sp. YATO411) isolated from an industrial petrochemical wastewater treatment plant under aerobic conditions were assessed with the nonlinear regression technique and with a trial‐and‐error procedure to determine the kinetic parameters. The growth rates of MTBE‐, benzene‐, and toluene‐degrading cultures on MTBE, benzene, and toluene were significant. Monod's model was a good fit for MTBE, benzene and toluene at low substrate concentrations. In contrast, Haldane's equation fitted well in substrate inhibition concentration. Monod and Haldane's expressions were found to describe the results of these experiments well, with fitting values higher than 98%. The kinetic parameters, including a maximum specific growth rate (µ_m), a half‐saturation constant (K_s), and an inhibition constant (K_i), were given. Copyright © 2007 Society of Chemical Industry     

Robust design of body slip angle observer for electric vehicles and its experimental demonstration

Electric vehicles (EVs) are inherently suitable for two‐dimensional vehicle motion control. To utilize EV's advantages, body slip angle β and yaw rate γ play an important role. However, as sensors to measure β are very expensive, we need to estimate β from only variables to be measurable. In this paper, an improved estimation method for body slip angle β for EVs is proposed. This method is based on a linear observer using side acceleration ay as well as γ information. We especially considered the design of gain matrix and succeeded in exact and robust estimation. We performed experiments by UOT March II. This experimental vehicle driven by four in‐wheel motors was made for research on advanced control of EVs. Some experimental results are shown to verify the effectiveness of the proposed method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 80–86, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20339     

On the information-based complexity of optimal reconstruction for nonlinear systems

The information-based complexity of optimal reconstruction problems for general nonlinear systems is studied. Both lower and upper bounds for the worst-case reconstruction-error functional are given. The existence of an optimal reconstruction algorithm which achieves the infimum of the reconstruction-error is established.     

From hot electron transport theory to macroscopic nonlinear and chaotic behavior induced by impact ionization in semiconductors

The status of our theoretical understanding of self-generated nonlinear and chaotic oscillations in semiconductors associated with impact ionization of impurity centers is reviewed from the viewpoint of hot electron transport theory. A set of hydrodynamic balance equations for the carrier density, mean momentum and energy is developed. It constitutes, together with Maxwell's equations, a macroscopic nonlinear dynamic system. We discuss various simplified versions of this model, which give rise to local or global bifurcations and hysteresis of limit cycle oscillations, a period-doubling route to chaos, mode-locking and quasiperiodicity, traveling waves, and breathing current filaments.     

小官庄铁矿承压区两翼开采回采顺序的研究

本文以小官庄铁矿东区为工程背景，在详细分析了其地压环境、采准进度、各矿块完成采准的可能时间、回采展开条件以及对产量要求的满足程度等基础上，提出三种回采方案，并采用三维非线性有限元计算进行方案比较，最后提出最优方案并付诸工程实施。本项研究对采用无底柱分段崩落法回采的类似矿山具有一定的参考价值。     

Spreadsheet template approach for nonlinear regression estimation

Industrial Engineers may encounter variables which are nonlinearly related such that the relationship cannot be transformed to one which is linear in the unknown parameters. One instance where this can occur is a learning curve which approaches a non-zero asymptote. This paper presents a spreadsheet template for implementing the Gauss-Newton Method for solving such nonlinear regression estimation problems.     

Equivalent nonlinearization of nonlinear systems to random excitations

The broadest class of solvable reduced Fokker-Planck equation is given and a new equivalent nonlinear method is presented to obtain an approximate probability density function for the response of a nonlinear oscillator to Gaussian white noise excitations. The method is based on the least mean-square criterion and Euler equation. It is shown that this method, which is simpler and more reasonable, generalizes Caughey's method and gives the same results as Cai and Lin under purely additive excitations. Examples are given to show the applications of the method. In one of the examples, this method leads to a better approximation than that obtained from the energy dissipation criterion.     

A generalization of the small-gain theorem for nonlinear feedback systems

A generalization is given of the usual small-gain theorem which allows greater flexibility in use of gain bounds for stability analysis of nonlinear feedback systems.     

Average function and variance function for diagnostic purposes

According to our experience, the variance function as the standard deviation of the average function is well suited as a diagnostic tool to monitor mechanical movements. Nonlinear effects during the movement can be detected using touch-induced or rub-induced vibrations to obtain direct information about loads to be expected. An application on a gearbox demonstrates the efficiency.     

Electron Charge Density Distribution from X-ray Diffraction Study of the M-Nitrophenol Compound in the Monoclinic Form

At room temperature, the m-Nitrophenol (m-NPH) appears in two polymorphic structures: orthorhombic and monoclinic forms. In the present work, we shall focus on the monoclinic form of this compound which has a centrosymmetric structure with the space group P2₁/n. The molecular dipole moment has been estimated experimentally. High resolution single crystal diffraction experiment was performed at low temperature with MoKα radiation. The crystal structure was refined using the multipolar model of Hansen and Coppens (1978). The molecular electron charge density distribution is described accurately. The study reveals the nature of inter-molecular interactions including charge transfer and hydrogen bonds. In this crystal, hydrogen bonds of moderate strength occur between the hydroxyl group and the O atom in the nitro one.