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41.
42.
Rotating biological contactor is being widely used for wastewater treatment but there is an apparent lack of knowledge about the rate at which oxygen transfer occurs, in physical and biological system. In this study the transfer of oxygen from air to water by a rotating disc air-liquid contactor in physical system is investigated. The oxygen transfer model suggested by Kim and Molof, Water Sci. Technol. 14 (1982) 569, was modified and the developed model is termed as modified Kim and Molof model. The model was calibrated by using available data in literature and validated by experiments conducted in this study. The effect of significant physical parameters was integrated into a single term and is termed as volume renewal number. The modified Kim and Molof model was compared with the other available models. The coefficient of determination (R(2)) for the modified Kim and Molof model obtained is 0.95 which is much higher than in the other available models. Thereby the model is expected to estimate oxygen transfer more accurately. Further, a simplified linear model between K(L)a and the volume renewal number is proposed. Both modified Kim and Molof and linear model estimate the overall oxygen transfer coefficient (K(L)a) accurately. 相似文献
43.
We develop a quasi-polynomial time approximation scheme for the Euclidean version of the
Degree-Restricted MST Problem by adapting techniques used previously by Arora for approximating TSP.
Given n points in the plane, d = 3 or 4, and > 0, the scheme finds an approximation with cost within 1 +
of the lowest cost spanning tree with the property that all nodes have degree at most d.
We also develop a polynomial time approximation scheme for the Euclidean version of the Red–Blue
Separation Problem, again extending Aroras techniques. Given > 0, the scheme finds an approximation
with cost within 1+ of the cost of the optimum separating polygon of the input nodes, in nearly linear time. 相似文献
44.
K. Sanjeev Rao 《Journal of Engineering Mathematics》2000,38(2):119-140
The viscous, laminar, separated flow downstream of a sudden expansion in a pipe is studied. The flow is modeled by an Oseen-type equation, but with the additional feature that the nonlinearity in the swirl is retained. Exact solutions are obtained for a high-Reynolds-number limit and for arbitrary Reynolds number by use of an eigenfunction-expansion procedure, in the presence of swirl. This leads to a non-standard eigenvalue problem. When the swirl is sufficiently large, a central recirculating region is observed. The effect of the pressure gradients on the velocity profiles and the central recirculating eddy is discussed. The low-Reynolds-number solutions go over smoothly to the large Reynolds number solution as the Reynolds number increases. Good agreement is obtained with the numerically computed value of the reattachment length. 相似文献
45.
Sanjeev Kumar Aydin Nassehi Stephen T. Newman Richard D. Allen Manoj K. Tiwari 《Robotics and Computer》2007,23(6):667-676
With today's highly competitive global manufacturing marketplace, the pressure for right-first-time manufacture has never been so high. New emerging data standards combined with machine data collection methods, such as in-process verification lead the way to a complete paradigm shift from the traditional manufacturing and inspection to intelligent networked process control. Low-level G and M codes offer very limited information on machine capabilities or work piece characteristics which consequently, results in no information being available on manufacturing processes, inspection plans and work piece attributes in terms of tolerances, etc. and design features to computer numerically controlled (CNC) machines. One solution to the aforementioned problems is using STEP-NC (ISO 14649) suite of standards, which aim to provide higher-level information for process control. In this paper, the authors provide a definition for process control in CNC manufacturing and identify the challenges in achieving process control in current CNC manufacturing scenario. The paper then introduces a STEP-compliant framework that makes use of self-learning algorithms that enable the manufacturing system to learn from previous data and results in eliminating the errors and consistently producing quality products. The framework relies on knowledge discovery methods such as data mining encapsulated in a process analyser to derive rules for corrective measures to control the manufacturing process. The design for the knowledge-based process analyser and the various process control mechanisms conclude the paper. 相似文献
46.
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48.
Sanjeev K. Srivastava Alireza Aghajamali 《Journal of Superconductivity and Novel Magnetism》2016,29(6):1423-1431
In this paper, we present the theoretical investigation and study of reflectance properties in a 1D ternary annular photonic crystal (TAPC) containing a semiconductor and a high-temperature superconductor. The proposed structure consists of alternate layers of indium nitride (InN), Bi2Sr2CaCu3O8 (BSCCO), and air placed in free space. A reflectance spectrum of the TAPC is obtained by employing the transfer matrix method (TMM) in the cylindrical waves for both transverse electric (TE) and transverse magnetic (TM) polarized waves. From the study of reflectance spectra, it is observed that the reflection band of the annular photonic crystal depends on the azimuthal mode number m in addition to other parameters. It is found that for azimuthal mode number m = 0, the width of the reflection band of the annular photonic crystal is the same as that of a planar photonic crystal (PPC). When the azimuthal mode number increases, the width of the reflection band increases at higher m values (m >5) for TE waves. In the case of the TM wave, it is interesting to observe that a superpolariton gap is created for a higher value of the azimuthal number (m >0). Further, we see the effect of the starting radius (ρ 0) on the reflection band of the TAPC structure at the given m number for both TE- and TM-polarized waves. Finally, the effect of temperature on the reflectance spectra for both TE and TM waves at the given ρ 0 and azimuthal mode has been studied. 相似文献
49.
This article presents a new nonlinear classifier by arranging linear classifiers in a tree structure. The proposed classifier, called the direct fractional-step linear discriminant (DF-LDA) tree, adopts a tree structure containing a DF-LDA at each node. The structure of the tree classifier evolves as the training proceeds, so there is no need to decide any parameters as a priori. Due to the many DF-LDAs arranged in the tree structure, classification performance of the proposed classifier is improved over single-shot DF-LDA. The proposed DF-LDA tree is tested on various synthetic and real datasets. Experimental results show that the proposed classifier leads to very satisfactory results in terms of classification accuracy. 相似文献
50.
Cormac O. Laoire Edward Plichta Mary Hendrickson Sanjeev Mukerjee K.M. Abraham 《Electrochimica acta》2009,54(26):6560-6564
We carried out a detailed study of the kinetics of oxidation of ferrocene (Fc) to ferrocenium ion (Fc+) in the non-aqueous lithium ion conducting electrolyte composed of a solution of 1 M LiPF6 in 1:1 EC:EMC solvent mixture. This study using cyclic (CV) and rotating disk electrode (RDE) voltammetry showed that the Fc0/Fc+ redox couple is reversible in this highly concentrated electrolyte. The ferrocene and ferrocenium ion diffusion coefficients (D) were calculated from these results. In addition, the electron transfer rate constant (k0) and the exchange current density for the oxidation of ferrocene were determined. A comparison of the kinetic data obtained from the two electrochemical techniques appears to show that the data from the RDE experiments are more reliable because they are collected under strict mass transport control. A Tafel slope of c.a. 79 mV/decade and a transfer coefficient α of 0.3 obtained from analysis of the RDE data for ferrocene oxidation suggest that the structure of the activated complex is closer to that of the oxidized specie due to strong interactions with the carbonate solvents. The experiments reported here are relevant to the study of redox reagents for the chemical overcharge protection of Li-ion batteries. 相似文献