Neural network trained morphological processing for the detection of defects in woven fabric

Basic morphological operations such as the erosion, dilation, opening, and closing often fail to detect various types of defects that may be present in woven fabric, mainly because of the heuristic selection of structuring element needed for these operations. In this paper, an artificial neural network (ANN) is utilized for the selection of structuring element, where ANN is trained by two pre‐assigned normalized numbers related to the warp and weft counts of the test fabric. The test gray fabric image is pre‐processed to remove noise and the interlaced grating structure of weft and warp and then converted to a binary image by thresholding. An intensity threshold value of the processed fabric image and the dimension of a sliding window needed for correlation operation are obtained from the trained ANN. Defects are detected after morphological reconstruction of the processed binary fabric image, where an ANN trained structuring element is used. The technique is tested on 317 samples for eight different types of defects in three types of plain woven fabrics from TILDA database and 92.8% success of detection is achieved.     

Cracking phenomena in lithium-di-silicate glass ceramics

Lithium-di-silicate glass ceramic (Li₂O, SiO₂) with uniformly oriented crystals was placed on a Vickers indentation with extrusion axis horizontally parallel to the base axis. The material was rotated through 0°–90° and at each angle a 20 N load was applied to ascertain the crack path. It was observed that the crack length decreases and the crack deviates from its original path with increasing angle. The deviation of the crack was correlated with the component of the crack driving force and the theoretical strength of the aligned crystals at different angles.     

NONLINEAR ANALYSIS OF POLYGONAL PLATES UNDER NONSTATIONARY TEMPERATURE

In this paper nonlinear thermal behaviors of polygonal plates have been investigated following a new approach. A conformal mapping technique has been employed in the investigation. Numerical results obtained for different polygons are given in tables and compared with other known results.     

Aggregate line capacity design for PWB assembly systems

In a multi-product, flexible manufacturing environment, line capacity of printed wiring board (PWB) assembly systems may need to be adjusted at the beginning of each aggregate planning period because of demand fluctuation over multiple periods. A model of production planning and equipment changeover scheduling at the aggregate level is developed. In the described model, three kinds of equipment changeover methods, i.e. adding machine, removing machine and transferring machine, are involved. Because the model is a large-scale integer programming problem, it cannot be solved directly. A solution approach is developed, which first solves a recursive linear programming problem to obtain a rough set of machines to be added and a rough set of machines to be removed for each machine line in each period, then applies a branch and bound heuristic to the rough sets to obtain near-optimal solutions to the equipment changeover scheduling problem. Computational studies show the financial benefit both on capital cost and equipment changeover costs.     

Thickness optimized nanocrystalline ZnO-coated silicon nanowires for cold cathode application

Silicon nanowire is an important material for the potential use as a cold cathode, but there are some bottlenecks like oxidation of the surface during field emission thereby degradation of its performance. To compete with carbon based nanostructures in this field the performance of Si nanowires as field emitter should be improved. Here, we report a simple technique for the significant improvement of field emission properties of Si nanowires by ZnO nanoparticle coating. Boron-doped p-type Si wafers were chemically etched to synthesize vertically aligned silicon nanowires and they were coated with different thicknesses of ZnO layer by radio frequency magnetron sputtering technique. The nanostructured thin films were studied by X-ray photoelectron spectroscopy for compositional and valence states information while their morphological information was obtained by a field emission scanning electron microscope and a high resolution transmission electron microscope. The field assisted electron emission performance of Si nanowires significantly improved for the thickness optimized ZnO coating. The photoluminescence spectra showed a peak at ~558 nm assigned to surface defect states of ZnO and the field emission from Si nanowires coated with ZnO for different times were correlated with the surface defect structures. The mechanism of such improvement is also discussed.     

Noise Analysis of Photorefractive Holograms Under Gaussian Beam Illumination

Abstract

Using a novel transfer function approach, we investigate the nature of the diffracted Gaussian beam from a photorefractive hologram under the influence of noise. The signal-to-noise ratio and spatial fidelity are defined, and their dependence on fringe spacing, temperature and reading beam intensity are discussed.     

Influence of Inlet Premixing on Two-Phase Flow Patterns in a Horizontal Minichannel

Experimental investigations are reported for air–water two-phase flow through a 2.1-mm horizontal circular minichannel. Influence of inlet premixing on two-phase flow is established by constructing various T-junction geometries with cross-flow arrangement of air and water. Six different flow patterns are observed and flow pattern maps are developed. The developed flow pattern maps are then compared for different inlet designs. It is observed that the degree of premixing of the two fluids has significant effect on flow patterns, particularly for surface-tension-dominated regime. The results obtained from these experiments can provide guidelines for selection, design, and control of wide-ranging microfluidic applications. The flow pattern map established in the present study may facilitate prediction of flow regimes in pulsating heat pipes based on the inlet flow rates of the gas and liquid.     

Production and delivery policies for enhanced supply chain partnerships

Recent research on supply chain management has highlighted the importance of building strong customer–supplier relationships in order to gain competitive advantage. This paper examines the benefits of buyer–supplier partnerships over lot-for-lot, i.e. single setup single delivery (SSSD) systems and suggests two policies that the supplier can pursue in order to meet customers’ needs: (1) Single setup multiple delivery (SSMD), and (2) Multiple setup multiple delivery (MSMD). If its fixed setup cost is relatively high, the supplier would prefer to implement SSMD and produce an entire order with one setup. However, if the supplier can reduce the setup cost and the supplier's capacity is greater than the threshold level (P?=?2D), it is more beneficial for the supplier to implement the multiple setups and multiple deliveries (MSMD) policy, even though he pays more frequent setup costs since the savings in inventory holding costs is greater than the increased setup costs. In the latter case, setup reduction is realized by the knowledge and efficiency gained through frequent setup operations. To provide guidelines for the policy selection, we examine the interactions among variables, such as production capacity, learning rate, and holding costs for both parties. The paper also discusses the benefit sharing plan, which discusses according to the contribution (or sacrifice) each party made to the partnership efforts.     

Effects of the Dipole Position on Thermomagnetic Convection in a Locally Heated Shallow Enclosure: Thermodynamic and Transport Analysis

Steady-state thermomagnetic convection in a shallow cavity under zero-gravity conditions is numerically investigated for different positions of the field-source. Two symmetrically placed, discrete, flush-mounted heaters of identical strengths represent power-dissipaters in electronics/MEMS applications. The sidewalls are isothermal heat sinks. Correlations between the field-source position and the flow morphology have been established. The distribution patterns of maximum heater temperatures and pertinent heat transfer parameters are explained. The local entropy generation due to heat transfer and fluid friction irreversibilities are determined. The total entropy generation is found to be almost entirely dependent on heat transfer irreversibility. The dipole position that minimizes the total entropy generation also produces the lowest average temperature on the heaters.     

Optimization of Solvent Extraction Process Parameters of Indian Coal

Medium coking coals from West Bokaro coalfield, India, were extracted with N-methyl-2-pyrrolidone (NMP) and ethylenediamine (EDA) under reflux condition at atmospheric pressure. The objective of the study was to maximize the clean coal yield maintaining the specified clean coal ash content. Experimentations using three level full factorial designs were carried out to elucidate the importance of variables such as extraction time, coal to solvent ratio, and filtration mesh size upon solvent extraction of coal. To determine the significance of the effects, Pareto chart, residual analysis, and surface plots were used. It was found that the maximum extraction yield was obtained for 1 h extraction time and 1:12 coal to solvent ratio. Finer mesh (0.025 mm) size in filtration was found favorable in producing low ash clean coal (CC). Under optimum conditions it was possible to produce clean coal with 6% ash and 55% yield for coals having about 29% ash.