Experimental approached optimisation of a linear motion performance with grey hazy set and Taguchi analysis methods (GHST) for ball-screw table type

In end effect to control a path, tracking, or cutting motion of CNC milling machine or other applications of machine tools, controlling its actuator, specifically a linear table motion, becomes a classical matter to be solved in industries. By applying an optimisation of grey hazy set Taguchi (GHST) analysis methods, it might get a performance improvement of a linear motion of ball-screw table type. In this paper, it is aimed to enhance on multi-performance characteristics, namely, displacement, velocity and torque. An improvement of an average error of position accuracy is from the 0.2100 to 0.0137 mm (S/N ratio from 13.4023 to 37.1935 dB). Average error of position time is significantly improved from 0.1599 to 0.0293 s (S/N ratio from 15.9229 to 29.9305 dB). The average error of torsion standard deviation from 0.0924 Nm is improved to 0.0481 Nm (S/N ratio from 20.5970 to 26.3447 dB). This study indicated that GHST analysis approach might be applied successfully to table motion performance optimisation, which is determined by many parameters at multi-quality performances.     

Efficient Simulation of Batch Distillation Processes by Using Orthogonal Collocation

Orthogonal collocation on finite elements is applied to discretize the DAE system for the simulation of multiple-fraction batch distillation processes. A detailed dynamic tray-by-tray model is used to describe batch columns more accurately which, however, leads to a set of model equations composed of nonlinear DAEs with a fairly high dimension. In addition, batch distillation operation usually takes a long period of time and therefore it costs large computational expense to simulate such processes. The use of orthogonal collocation is demonstrated to obtain a stable and highly accurate algebraic representation of the differential equations so as to improve the computational efficiency significantly. Because of the orthogonality of the polynomials introduced to approximate the state variables within a time interval, large integration steps can be taken with the collocation approximation without reducing the computational accuracy. Through simulation of two real batch distillation processes it is found that with this discretization approach 50% CPU time can be saved in comparison to the implicit Euler method normally used.     

Measurements of the Thermal Conductivity and Thermal Diffusivity of Polymer Melts with the Short-Hot-Wire Method

In this paper, the thermal conductivity and thermal diffusivity of four kinds of polymer melts were measured by using the transient short-hot-wire method. This method was developed from the hot-wire technique and is based on two-dimensional numerical solutions of unsteady heat conduction from a wire with the same length-to-diameter ratio and boundary conditions as those in the actual experiments. The present method is particularly suitable for measurements of molten polymers where natural convection effects can be ignored due to their high viscosities. The results have shown that the present method can be used to measure the thermal conductivity and thermal diffusivity of molten polymers within uncertainties of 3 and 6%, respectively. Further, the thermal conductivity and thermal diffusivity of solidified samples were also measured and discussed.     

An application of genetic algorithm for edge detection of molten pool in fixed pipe welding

This paper presents a study on an application of genetic algorithm (GA) for edge detection of molten pool in fixed pipe welding. As circumferential butt-welded pipes are frequently used in power stations, offshore structures, and process industries, it is important to investigate the characteristic of the welding process. In pipe welding using constant arc current and welding speed, the bead width becomes wider as the circumferential welding of small-diameter pipes progresses. In order to avoid the errors and to maintain the uniform weld bead over the entire circumference of the pipe, the welding conditions should be controlled as the welding proceeds. This research studies the intelligent welding process of aluminum alloy pipe 6063S-T5 in fixed position using the AC welding machine. The monitoring system used an omnidirectional camera to monitor backside image of molten pool. A method of optimization for image processing algorithm using GA was proposed and has been implemented into a process to recognize the edge of molten pool. The result of detection, which is back bead width, was delivered into a fuzzy inference system to control welding speed. The experimental results show the effectiveness of the control system that is confirmed by a sound weld of the experimental results.     

Mean-Shift Object Tracking with Discrete and Real AdaBoost Techniques

An online mean-shift object tracking algorithm, which consists of a learning stage and an estimation stage, is proposed in this work. The learning stage selects the features for tracking, and the estimation stage composes a likelihood image and applies the mean shift algorithm to it to track an object. The tracking performance depends on the quality of the likelihood image. We propose two schemes to generate and integrate likelihood images: one based on the discrete AdaBoost (DAB) and the other based on the real AdaBoost (RAB). The DAB scheme uses tuned feature values, whereas RAB estimates class probabilities, to select the features and generate the likelihood images. Experiment results show that the proposed algorithm provides more accurate and reliable tracking results than the conventional mean shift tracking algorithms.     

Spatial data analysis and integration for regional-scale geothermal potential mapping,West Java,Indonesia

Conceptual modeling and predictive mapping of potential for geothermal resources at the regional-scale in West Java are supported by analysis of the spatial distribution of geothermal prospects and thermal springs, and their spatial associations with geologic features derived from publicly available regional-scale spatial data sets. Fry analysis shows that geothermal occurrences have regional-scale spatial distributions that are related to Quaternary volcanic centers and shallow earthquake epicenters. Spatial frequency distribution analysis shows that geothermal occurrences have strong positive spatial associations with Quaternary volcanic centers, Quaternary volcanic rocks, quasi-gravity lows, and NE-, NNW-, WNW-trending faults. These geological features, with their strong positive spatial associations with geothermal occurrences, constitute spatial recognition criteria of regional-scale geothermal potential in a study area. Application of data-driven evidential belief functions in GIS-based predictive mapping of regional-scale geothermal potential resulted in delineation of high potential zones occupying 25% of West Java, which is a substantial reduction of the search area for further exploration of geothermal resources. The predicted high potential zones delineate about 53–58% of the training geothermal areas and 94% of the validated geothermal occurrences. The results of this study demonstrate the value of regional-scale geothermal potential mapping in: (a) data-poor situations, such as West Java, and (b) regions with geotectonic environments similar to the study area.     

Shorting strap tunable single feed dual-band PIFA

RF switches are integrated to the shorting straps of a single feed dual-band planar inverted-F antenna (PIFA) to make a tunable PIFA. The L-band switch yields 0.45-dB insertion loss (IL) and 10-dB isolation bandwidth (BW) of 40% at 1.5 GHz. The tunable PIFA yields 39% impedance BW at 900-MHz band and 7.8% BW at 2000-MHz band. The measured radiation patterns are nearly omni-directional and yield a gain of -7.8 dBi at 652 MHz and 4.3 dBi at 2104 MHz.     

New Design of Conduit Plasma Atomization for Fabricating Spherical Metal Powder and its Optimization Using Design of Experiments Method

Powder Metallurgy and Metal Ceramics - This research presents a new design of plasma atomization conducted using a graphite plasma conduit to assure prolonged interaction between molten metal and...