Finite Element Method Application to Determine Appropriate Splitting Parameters for Dimensional Stone Quarries

In dimension stone extraction, there have existed many block cutting techniques from intact rock or from a large block to smaller blocks such as disc sawing, chainsawing, diamond wire sawing and splitting techniques, one of which still has recently been used with the other modern methods is splitting techniques. The usage of the splitting methods has still based on the practical experience of mining workers on calculating the spacing of two holes in the co-planar line, resulting in increasing the roughness of the cutting face. The paper studies a relationship between beating force and two-hole spacing based on rock mass properties of dimension stone in order to find proper splitting parameters. The paper deploys the Finite Element Method (FEM) with computer simulation in 2D using Phase2 software. From input data including rock mechanics (unit density, Young’s modulus, Poisson’s rate), compressive pressure on the hole wall due to the force, the spacing, the simulation represents stress and displacement distributions along the two adjacent holes. A regression function for a relationship between the pressure and the spacing is established with the results of stress distribution along the two adjacent holes, compared to uniaxial tensile strength through running the software, which leads to making suggestions to appropriate splitting parameters.

REDUCING SHORT CIRCUIT LEVELS BY USING SYSTEM SPLITTING STRATEGIES

Preliminary studies on Iraqi power system show a significant increase in the short circuit level at some of the grid substations and some power stations. This increasing results from the growth of the power generation and transmission systems in size and complexity. Islanding or splitting is dividing the power system into several islands inorder to reduce short circuit levels and avoiding blackouts. The main islanding problem is determining the location of proper splitting points and load balance and satisfaction of transmission capacity constraints for each islands.This paper mainly introduces new proposed splitting strategies of large-scale power systems by using (PSS™E version 30.3 PACKAGE PROGRAME), such that, make re-interconnection of 400KV super high voltage substation based on three-phase load flow to be minimum flow at splitting point and infeed fault current details method to control short circuit levels in Iraq power system without islanding the power system into isolated islands. Controlled islanding or splitting scheme is frequently considered as the final solution to avoid blackouts of power system.Simulation IEEE-25 bus and Iraqi power system used as the test systems for this method. Furthermore, simulation results show significant effectiveness on reducing short circuit levels with same time give stable splitting islands with same frequency for preventing the system blackouts.

Reverse proper splittings of rectangular matrices

In this article, we introduce a new splitting for rectangular matrices called reverse proper splitting. We then propose several subclasses of this splitting and also discuss convergence results for these splittings.

Proper Splitting for the Generalized InverseAT,S(2)and Its Application on Banach Spaces

A possible type of the operator splitting is studied. Using this operator splitting, we introduce some properties and representations of generalized inverses as well as iterative method for computing various solutions of the restricted linear operator systemAx=b, x∈T, whereA∈ℒ(X,Y)andTis an arbitrary but fixed subspace ofX.

Multiscale Modeling of a Quantum Dot Heterostructure

ABSTRACTA multiscale approach was adopted for the calculation of confined states in self-assembled semiconductor quantum dots (QDs). While results close to experimental data have been obtained with a combination of atomistic strain and tight-binding (TB) electronic structure description for the confined quantum states in the QD, the TB calculation requires substantial computational resources. To alleviate this problem an integrated approach was adopted to compute the energy states from a continuum 8-band k.p Hamiltonian under the influence of an atomistic strain field. Such multiscale simulations yield a roughly six-fold faster simulation. Atomic-resolution strain is added to the k.p Hamiltonian through interpolation onto a coarser continuum grid. Sufficient numerical accuracy is obtained by the multiscale approach. Optical transition wavelengths are within 7% of the corresponding TB results with a proper splitting of p-type sub-bands. The systematically lower emission wavelengths in k.p are attributable to an underestimation of the coupling between the conduction and valence bands.

Almost Classically Damped Continuous Linear Systems

The dynamic response of a general class of continuous linear vibrating systems is analyzed which possess damping properties close to those resulting in classical (uncoupled) normal modes. First, conditions are given for the existence of classical modes of vibration in a continuous linear system, with special attention being paid to the boundary conditions. Regular perturbation expansions in terms of undamped modeshapes are then utilized for analyzing the eigenproblem as well as the vibration response of almost classically damped systems. The analysis is based on a proper splitting of the damping operators in both the field equations and the boundary conditions. The main advantage of this approach is that it allows application of standard modal analysis methodologies so that the problem is reduced to that of finding the frequencies and mode shapes of the corresponding undamped system. The approach is illustrated by two simple examples involving rod and beam vibrations.

Indication of Odd Number of Equivalent Atoms in an EPR Spectrum by the Fourier Transform

A numerical criterion is proposed for the indication of odd number of equivalent atoms in an EPR spectrum. Physically, this "oddness" criterion is the relation for the content of negative and positive parts of the imaginary part of the EPR spectrum Fourier transform, provided that the spectrum x-coordinate start is shifted into the spectrum symmetry center. The effect of noise present in the spectrum is analysed and the best limit of Fourier transform noise effect minimalization is proposed. With even numbers of equivalent atoms in EPR spectrum only, the oddnes criterion value for the noiseless spectrum is zero and the deviation from this value is due to the effect of the noise. A criterion value greater than 0.3 indicates the presence of at least one well-resolved component with an odd number of equivalent atoms, with spin 1/2 in the spectrum. A value smaller than 0.3 indicates the absence of such component. However, if this value is greater than 1.0, the presence of either a well resolved component with a single atom with spin 1 or an ill-resolved component with an odd number of equivalent atoms with spin 1/2 is indicated. Application of the proposed criterion to noise-loaded synthetic EPR spectra is exhibited. The possibility of identifying methyl group splitting by a sharp decrease of the proposed criterion value after the spectrum contraction with the proper splitting constant is demonstrated.