Effect of coke quality on blast-furnace performance indices

The quality of coke has a strong effect on the performance indices of a blast furnace. For a furnace to operate with high productivity and a low coke rate, it is necessary to use coke with high strength characteristics. The Novolipetsk Metallurgical Combine has conducted studies of the effect of coke quality on the operation of blast furnaces of different sizes. The quality of the coke was evaluated on the basis of the following indices: CSR, CRL, the cold-strength indices M₁₀ and M₂₅, and the integral coke-quality index I_g.c used by the Sidmar company. Furnace productivity, coke rate, and the totterman index (DMI) were also used for the sake of comparison.     

PETOOL: MATLAB-based one-way and two-way split-step parabolic equation tool for radiowave propagation over variable terrain

A MATLAB-based one-way and two-way split-step parabolic equation software tool (PETOOL) has been developed with a user-friendly graphical user interface (GUI) for the analysis and visualization of radio-wave propagation over variable terrain and through homogeneous and inhomogeneous atmosphere. The tool has a unique feature over existing one-way parabolic equation (PE)-based codes, because it utilizes the two-way split-step parabolic equation (SSPE) approach with wide-angle propagator, which is a recursive forward–backward algorithm to incorporate both forward and backward waves into the solution in the presence of variable terrain. First, the formulation of the classical one-way SSPE and the relatively-novel two-way SSPE is presented, with particular emphasis on their capabilities and the limitations. Next, the structure and the GUI capabilities of the PETOOL software tool are discussed in detail. The calibration of PETOOL is performed and demonstrated via analytical comparisons and/or representative canonical tests performed against the Geometric Optic (GO) + Uniform Theory of Diffraction (UTD). The tool can be used for research and/or educational purposes to investigate the effects of a variety of user-defined terrain and range-dependent refractivity profiles in electromagnetic wave propagation.

Program summary

Program title: PETOOL (Parabolic Equation Toolbox)Catalogue identifier: AEJS_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJS_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 143 349No. of bytes in distributed program, including test data, etc.: 23 280 251Distribution format: tar.gzProgramming language: MATLAB (MathWorks Inc.) 2010a. Partial Differential Toolbox and Curve Fitting Toolbox requiredComputer: PCOperating system: Windows XP and VistaClassification: 10Nature of problem: Simulation of radio-wave propagation over variable terrain on the Earth?s surface, and through homogeneous and inhomogeneous atmosphere.Solution method: The program implements one-way and two-way Split-Step Parabolic Equation (SSPE) algorithm, with wide-angle propagator. The SSPE is, in general, an initial-value problem starting from a reference range (typically from an antenna), and marching out in range by obtaining the field along the vertical direction at each range step, through the use of step-by-step Fourier transformations. The two-way algorithm incorporates the backward-propagating waves into the standard one-way SSPE by utilizing an iterative forward–backward scheme for modeling multipath effects over a staircase-approximated terrain.Unusual features: This is the first software package implementing a recursive forward–backward SSPE algorithm to account for the multipath effects during radio-wave propagation, and enabling the user to easily analyze and visualize the results of the two-way propagation with GUI capabilities.Running time: Problem dependent. Typically, it is about 1.5 ms (for conducting ground) and 4 ms (for lossy ground) per range step for a vertical field profile of vector length 1500, on Intel Core 2 Duo 1.6 GHz with 2 GB RAM under Windows Vista.     

Micro-milling performance of AISI 304 stainless steel using Taguchi method and fuzzy logic modelling

In this study, micro-milling of AISI 304 stainless steel with ball nose end mill was conducted using Taguchi method. The influences of spindle speed, feed rate and depth of cut on tool wear, cutting forces and surface roughness were examined. Taguchi’s signal to noise ratio was utilized to optimize the output responses. The influence of control parameters on output responses was determined by analysis of variance. In this study, the models describing the relationship between the independent variables and the dependent variables were also established by using regression and fuzzy logic. Efficiency of both models was determined by analyzing correlation coefficients and by comparing with experimental values. The results showed that both regression and fuzzy logic modelling could be efficiently utilized for the prediction of tool wear, cutting forces and surface roughness in micro-milling of AISI 304 stainless steel.     

Combining functional near-infrared spectroscopy and EEG measurements for the diagnosis of attention-deficit hyperactivity disorder

Neural Computing and Applications - Recently multimodal neuroimaging which combines signals from different brain modalities has started to be considered as a potential to improve the accuracy of...     

Interactions of silicone rubbers designed for electrical engineering applications with aqueous media

Interactions of a number of electrical engineering silicone rubbers with water and aqueous salt, weakly acidic, and weakly basic solutions were studied by measuring contact angles. A mechanism for leakage currents along the surfaces of silicone insulators was proposed.     

Annealing effect on reflectivity spectra of opal photonic crystals

We analyze broadband visible reflectivity spectra of opal photonic crystals annealed in an argon atmosphere and air. Scanning electron microscopic examination has shown that the crystals consist of close-packed spheres with a mean diameter in the range 200–290 nm. Incorporation of even small amounts of carbon (?0.5 wt %) increases the density of the opal matrix. The presence of carbon shifts the Bragg reflection peak of the opal and increases its intensity.     

Capacitance-voltage characteristics of p-n structures based on (111)Si doped with erbium and oxygen

Capacitance-voltage characteristics of tunneling diodes fabricated by co-implantation of erbium and oxygen in single-crystal (111)Si wafers have been studied. Anomalous enhancement of the p-n-junction capacitance with increasing reverse bias has been observed at certain temperatures depending on the implantation dose. The rise in capacitance (decrease in the space charge region width) is associated with the formation of deep levels of high density in the band gap of n-layer of the p-n junction and electron emission from these levels in the space charge region with increasing voltage. The obtained results show that the parameters of the defects responsible for the levels depend on the erbium and oxygen implantation doses.     

Electrothermal instability of a polar polymer dielectric above the glass transition temperature

A stationary temperature state of a polar polymer dielectric exposed to an electric field is studied. A special feature of the dielectrics of this type is the presence of a maximum in the loss factor ε″(T) above the glass transition temperature. Using an approach based on the Kirkwood formula for ε″(T), exact solutions to a nonlinear model problem are obtained. These solutions show the multiplicity of the stationary temperature states and the surface of these states in the “load-ambient temperature” space of parameters exhibits a topological singularity of the “fold” type.