Analysis and design of synchronous permanent-magnet planar motors

The force equation of a synchronous permanent-magnet planar motor (SPMPM) was investigated. The flux density distribution of a two-dimensional (2-D) magnet array for a SPMPM was obtained by solving the equations of the scalar magnetic potential. The expressions of the force and back-EMF constant were derived and examined. Using these expressions, the conditions for normal operation of the SPMPM were found and the optimal design was determined in order to maximize the force of the SPMPM.     

Buckling analysis for delaminated composites using plate bending elements based on higher‐order zig‐zag theory

A finite element based on the efficient higher‐order zig‐zag theory with multiple delaminations is developed. The bending part of the formulation is constructed from the concept of DKQ element. Unlike conventional elements, a developed element has its reference in the bottom surface which simplifies zig‐zag terms on formulation. Exact patch solutions are developed on elements which have the bottom reference system. The present element passes proper bending patch tests in the arbitrary mesh configurations in isotropic materials. Zig‐zag formulation is adopted to model laminated plates with multiple delaminations. To assess the accuracy and efficiency of the present element based on higher‐order zig‐zag theory with multiple delaminations, the linear buckling problem of laminated plates with multiple delaminations has been analysed. The results have been compared with three‐dimensional elasticity solutions. The present element works as an efficient tool for analysing the behaviour of the laminated composites with multiple delaminations. Copyright © 2002 John Wiley & Sons, Ltd.     

Elastic-plastic thermal stresses and deformation of short-fibre composites

A micromechanics model is proposed to analyse residual stresses and deformations that develop in short-fibre composites upon an applied uniform temperature change. The model is based on Eshelby's equivalent inclusion method and treats the interaction among fibres at finite volume fractions through the Mori-Tanaka mean field theory. The model treats the matrix as an elastic/plastic material while the fibre is elastic and is able to account for the effects of the composite microgeometry. To this end, the effects of misoriented short fibres, the orientation of which is described by a density distribution function, are considered. Numerical results obtained from the proposed model indicate that the misorientation of short fibres has a significant effect on both the stress and deformation behaviour of short-fibre composites.     

Low-power high-slew-rate CMOS buffer amplifier for flat panel display drivers

A new high-slew-rate CMOS buffer amplifier consuming a very small quiescent current is proposed. This buffer amplifier recursively copies the output driving current and increases the tail current of the input differential pair during slewing. Since the proposed buffer has a possible slew rate higher than 10 V//spl mu/s for a load capacitance of 1 nF almost independently of static currents as low as 1 /spl mu/A, this buffer amplifier is promising for column driver ICs of flat panel displays that require low static power consumption, high current driving capabilities, and small silicon areas.     

The law of mixtures applied to the plastic deformation of two- phase alloys of coarse microstructures

The theory of the mechanical law of mixtures is reviewed and applied to the partition of stress and of strain in two-phase alloys. It is shown that the modified law of mixtures, based on averagein situ stress and strain, is valid for small deformations and is compatible with strengthening theories based on continuum and dislocation mechanics. The plastic deformation behavior of two representative two-phase alloys,i.e., a spheroidized high carbon steel and a duplex stainless steel, was studied by taking into account the mutual interactions between phases. The law of mixtures and dispersion strengthening theory were used to evaluate the strength contribution of each phase.     

Computational Implementation of Asymmetric Integral Imaging by Use of Two Crossed Lenticular Sheets

We propose an asymmetric integral imaging method to adjust the resolution and depth of a three‐dimensional image. Our method is obtained by use of two lenticular sheets with different pitches fabricated under the same F/#. The asymmetric integral imaging is the generalized version of integral imaging, including both conventional integral imaging and one‐dimensional integral imaging. We present experimental results to test and verify the performance of our method computationally.     

Experimental investigation of natural convection from a horizontal ice surface melting in pure water

A study on natural convection from a horizontal ice surface melting in pure water was conducted experimentally for the ambient water temperature from 2▿C to 10°C. Natural convection flow around upward-or downward-facing horizontal ice plate was divided into three regions according to the temperature variation of ambient water. The flow patterns of three regions were no flow, two-dimensional steady laminar flow and unsteady flow. Mean Nusselt number for the upward-facing surface had its maximum value at about 3°C of ambient water temperature. However, in the case of the downward-facing surface it increased as the ambient water temperature increased.     

Feature selection techniques and comparative studies for large-scale manufacturing processes

In order to efficiently and effectively control an overall process in the process industry, a few important parameters should be identified from high-dimensional, non-linear, and correlated data. Feature selection techniques can be employed to extract a subset of process parameters relevant to product quality. The performance of these techniques depends on the precision of the prediction model formulated to quantify the relationship between the process parameters and the quality characteristics. Although the neural network-based partial least squares (NNPLS) method has been proven to be effective in prediction models for the aforementioned industrial process data, feature selection techniques appropriate for NNPLS models have yet to appear. Here, several techniques for scoring the relevance of process parameters to product quality are proposed and validated by applying three datasets. These experiments show that the proposed techniques can discriminate relevant process parameters from irrelevant ones.     

Aluminum deoxidation equilibrium in liquid Ni-Fe alloys equilibrated with CaO-Al2O3 slags

The deoxidation equilibrium for Al in Ni-Fe alloys was studied in the equilibrium experiments between CaO-Al₂O₃ slags and Fe-30, 50 and 70 % Ni alloys at 1873 K. By using the values for the first and second order interaction parameters between oxygen and nickel in liquid iron and those between oxygen and iron in liquid nickel, the effect of Ni on the activity coefficient of Al in liquid iron and that of Fe on the activity coefficient of Al in liquid nickel were determined in the whole composition range of Ni-Fe alloys. The oxygen contents in Ni-Fe alloys calculated by the iterative method based on pure iron were in good agreement with those based on pure nickel in the range of [% Al] < 0.03. From this fact, it was found that the Wagner's approximation relating to the multi-component solution was applicable to the deoxidation equilibrium in the whole composition range of Ni-Fe alloys in the restricted concentration of a deoxidizer.