Crystallization characteristics of the Ti53Cu47 amorphous alloy

A thin Ti₅₃Cu₄₇ amorphous ribbon was prepared by rapid quenching from the melt. The crystallization behavior was investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The DSC results indicated that the activation energy for crystallization was 170 or 150 kJ/mole (1.76 or 1.55 eV/atom) based on the Kissinger or Arrhenius plot, respectively, which is close to that of chemical diffusion in the TiCu alloy: 166 kJ/mol (1.72 eV/atom). The Johnson-Mehl-Avrami (JMA) plot exhibited a linearity, with an exponent of n=2.0 ±0.2. The XRD patterns revealed the transformation to the equilibrium γ-TiCu phase. However, broad peaks due to nanocrystalline grains were not observed. From the TEM analysis, there was a metastable phase with an fcc structure based on the Cu structure pre-existing in the as-quenched ribbon. Only a few TiCu particles in the nanoscale dimension were observed to precipitate from the amorphous matrix upon both continuous and isothermal heatings. A theoretical calculation demonstrates that amorphous Ti₅₃Cu₄₇ has a very low nucleation frequency and thus, a low tendency to form nanocrystals.     

Mechanism and kinetic modelling of PEEK pyrolysis by TG/MS

A new technique combining Py-GC/MS with TG/MS can be used in analyzing the mechanism and kinetic modelling of pyrolysis. The results of this study show that a combined approach of Py-GC/MS and TG/MS exhibited dynamic curves of 13 evolved gases from the pyrolysis of PEEK from room temperature to 900°C. In this study we also discovered that there are two stable pyrolysis reaction regions during the pyrolysis in helium atmosphere at a heating rate of 10°C/min from room temperature to 900°C. In the first pyrolysis region the ether group and ketone group from the main chain of PEEK decomposed to phenol and CO₂, respectively. It also showed that the thermal stability of the ketone group was better than that of the ether group. Accompanied with the chain transfer in the first pyrolysis region, the fluorenone structure appeared in part of the carbonization scheme. Above 650°C it moved to the second reaction region. In this region the main decomposition products were CO₂ from the ketone group of fluorenone and from the carbonized structure described above. From the two flat regions of the activation energy curve of pyrolysis, we have proposed a kinetic model with two pyrolysis regions. Based on this model, we compared the theoretical pyrolysis curve with the experimental curve, the two curves being quite similar.     

An Integrated Data-Driven Framework for Computing System Management

With advancement in science and technology, computing systems are becoming increasingly more complex with a growing number of heterogeneous software and hardware components. They are thus becoming more difficult to monitor, manage, and maintain. Traditional approaches to system management have been largely based on domain experts through a knowledge acquisition solution that translates domain knowledge into operating rules and policies. This process has been well known as cumbersome, labor intensive, and error prone. In addition, traditional approaches for system management are difficult to keep up with the rapidly changing environments. There is a pressing need for automatic and efficient approaches to monitor and manage complex computing systems. In this paper, we propose an integrated data-driven framework for computing system management by acquiring the needed knowledge automatically from a large amount of historical log data. Specifically, we apply text mining techniques to automatically categorize the log messages into a set of canonical categories, incorporate temporal information to improve categorization performance, develop temporal mining techniques to discover the relationships between different events, and take a novel approach called event summarization to provide a concise interpretation of the temporal patterns.     

Establishing a Demerit Count Reference Standard for the Classification and Grading of Leather Hides

Leather hide, as a natural material, may have many types of undesirable surface defects. No analytical method has been devised for classifying and grading wet blue hide surface defects. A high return rate and disputes between the customer and manufacturing company usually cause additional costs. This paper proposes a semi-automatic machine vision method to measure the unusable surface defect areas in wet blue hides and a clear reference standard for the demerit count for graders to classify and grade wet blue hides. A statistical comparative evaluation of the grade deviation rate and a practical demerit count method for tannery performance are given to show the usefulness of the proposed approach. a clear evaluation standard for leather surface quality usually causes much argument between the tanneries and the leather.       

Automated bonding position inspection on multi-layered wire IC using machine vision

No available method can automatically verify the correctness of the wire bonding positions on a multi-layered wire IC. This paper presents a novel method that integrates image processing and wire bonding simulation techniques. The proposed method first takes the IC leadframe image and calculates the lead information before actual wire bonding begins. The wire bonding position information is then generated to simulate the actual wire bonding process. The generated pseudo bonding information is then compared with that from a referential machine. This approach can check the wire bonding position correctness before any actual wire bonding is executed. This approach can fully solve the mal-detection and lost detection problems that may occur in other available methods. The experimental results show that the proposed bonding position check (BPC) method is robust and fast enough for applied multi-layered wire IC inspection synchronously with the wire bonding process.     

Directional textures auto-inspection using discrete cosine transform

This paper describes a global image restoration scheme using a discrete cosine transform (DCT) that can be used to detect defects in directional textured surfaces automatically. The input spatial domain image is first transformed into the DCT domain so that the dominant directions of the texture in the input image will be compacted into the orthogonal straight lines or impulses through the direct current (DC) component of the spectrum. The linear primitives associated with the high-energies in the DCT domain are eliminated by reducing them to zero before transforming back to the spatial domain. Finally, the defects, if any, are extracted by the thresholding method. Experiments on a variety of product surfaces with directional textures such as straight, slanted, orthogonal, slanted orthogonal, and oblique linear primitives were conducted in this paper. The proposed scheme would blur directional textures and preserved only local defects if they were initially embedded in the image. Furthermore, some preliminary experiments were also conducted to demonstrate the proposed scheme was insensitive to horizontal and vertical shifting, changes in illumination, and image rotation.     

The design of an intelligent real‐time autonomous vehicle,TAIWAN iTS‐1

Abstract

Developed at National Chiao Tung University, TAIWAN iTS‐1 is the first smart car with active safety systems and comfortable autonomous driving in Taiwan. An adaptive vision‐based lane detection algorithm was proposed to help the lateral control unit to keep the car in its lane safely. It also carries a DSP system to generate warning signals for unintentional roadway departures. A laser radar measures the distance between the preceding car and TAIWAN iTS‐1. With this information, the longitudinal control unit performs intelligent cruise control and stop‐and‐go functions. The remote control function is realized on TAIWAN iTS‐1 for safety testing and military applications. Unlike most smart car studies, this paper considers not only driving safety demands but also non‐driving security. An active mobile surveillance system will inform the car owner when the car is illegally broken into, anytime and anywhere. For drivers and passengers, the perception of comfort is achieved by intelligent vehicle dynamic control. All functions integrated into TAIWAN iTS‐1 have been tested repeatedly on National Highway 3 and Expressway 68 in the Hsinchu area and the system's robustness has been successfully demonstrated in these real‐road experiments.     

Numerical investigation of heat transfer enhancement on a porous vortex-generator applied to a block-heated channel

The numerical simulation is used to obtain the unsteady laminar flow and convective heat transfer in the block-heated channel with the porous vortex-generator. The general Darcy–Brinkman–Forchheimer model is adopted for the porous vortex-generator. The parameters studies including porosity, Darcy number, width-to-height ratio of porous vortex-generator and Reynolds number have been explored on heat transfer enhancement and vortex-induced vibration in detail. The results indicate that heat transfer enhancement and vortex-induced vibration increase with increasing Reynolds number and width-to-height ratio. However, the porosity has slight influence on heat transfer enhancement and vortex-induced vibration. When Darcy number is 10^?3 or 10^?4, installing a porous vortex-generator with B/h = 1.0 improves overall heat transfer the best along heated blocks, and has a strong reduction of vortex-induced vibration.     

A novel internal thread defect auto-inspection system

This paper describes a novel optical thread plug gauge (OTPG) for internal thread inspection using machine vision. The OTPG is composed of a rigid industrial endoscope, a charge-coupled device camera, and a two degree-of-freedom motion control unit. A sequence of partial wall images of an internal thread are retrieved and reconstructed into a 2D unwrapped image. Then, a digital image processing and classification procedure is used to normalize, segment, and determine the quality of the internal thread. The proposed OTPG provides an orientation-free and convenient method for detecting defects such as scratches, collapses, and flaws in an internal thread.     

Comparison of solvent removal methods of microporous polypropylene tubular membranes via thermally induced phase separation using a novel solvent: Camphene

A novel solvent, camphene, was used to prepare microporous polypropylene tubular membranes via thermally induced phase separation (TIPS). In this process, camphene was removed by either sublimation or extraction. The effect of the solvent-removal on the structure and properties of the resulting membrane was studied. Microscopic observation and wide angle X-ray scattering indicate that the morphology and crystalline structure difference is minor. Thermal analysis and tensile tests reveal that the crystallinity and breaking strength of the tubular membrane from the extracting method are slightly higher than those for the sublimating method. Porosity measurements show that the sublimation method can yield membranes with slightly higher porosity than the extraction method. Furthermore, permeation results indicate that membranes from extraction have a smaller permeation rate and higher retention. Therefore solvent-extraction can produce a denser membrane structure than sublimation can.