The value of the bipolar electrocoagulator in the haemostasis of bleeding ulcers is controversial. We have therefore investigated the effect of different coagulation times on vessel weld strength achieved by the bipolar device. Welds were then made in vessels of known diameter using a standard 10F endoscopic haemostatic probe at coagulation times of two and 20 seconds. The intravascular tempera...

This paper presents a new method for measuring and classifying spatter in gas metal arc welding (GMAW) by optical monitoring of the weld pool and surrounding area via a high-frame-rate camera. Image processing and tracking algorithms are described that extract and classify individual spatter events from raw camera images. This new sensor is then used to investigate the relationship between work...

Ultrasonic phased arrays are a new technology that offers considerable potential for inspecting construction welds. Using electronic control of the beam, phased arrays can scan, sweep, steer and focus the ultrasound. Since welds typically produce defects of known character and orientation, phased arrays can be programmed to optimize weld inspections. These inspections include standard ASME-type...

Research has cshown,'s!;udent 'field-independent cognitive stVle (FT),_as opposed to fleld-dependent Eognitiie style (FD), to be correlated moderately witlt success on selected second lanauage tasks..A trait treatment interaCtion approach was utilized in this study to examine the role of F6 /I among 236.collegs Students enrolled in six sections of an tntroductory Spanish course. The _ 'ourObse ...

The friction stir welding process has been used to join 13mm gauge 2024-T351 aluminium alloy plates together. A detailed microstructural study of the resulting weld was carried out using Differential Scanning Calorimetry (DSC), hardness testing, Scanning Electron Microscopy (SEM) and Electron Backscatter Diffraction (EBSD). DSC was used to explain the hardness results at a number of regions acr...

This paper addresses the problems involved in the automatic monitoring of the weId quality produced by robotized short-arc welding. A simple statistical change detection algorithm for the weld quality, the repeated Sequential Probability Ratio Test (SPRT), was used. The algorithm may similarly be viewed as a cumulative sum (CUSUM) type test, and is well-suited to detecting sudden minor changes ...

Of particular importance and interest are the effects of pulsed Nd:YAG laser beam welding parameters on penetration and microstructure characterization of DP1000 butt joint, which is widely used in the automotive industry nowadays. Some key experimental technologies including pre-welding sample preparation and optimization design of sample fixture for a sufficient shielding gas flow are perform...

On-l ine quality control in automated welding operations is an important factor contributing to higher productivity, lower costs and greater reliability of the welded components. However, the development of on-l ine inspection techniques and feedback control is still in its infancy. Sound signature produced by GMAW contains information about the behavior of the arc column, the molten metal and ...

Finite element analysis (FEA) has become a practical method of predicting stresses and deflection for loaded structures. FEA accurately identifies the load path, which can be difficult using classical analysis with complex structures. FEA shell element models are effective for predicting loads in weldments fabricated from plate, sheet, structural shapes and tube. The formulation used for a fini...

High strength steels Q690+Q550 were welded using three different welding wires without preheating by gas shielded arc welding process. Microstructural characteristics of weld metals and nucleation mechanism of acicular ferrite were investigated by means of scanning electron microscope (SEM), energy dispersive spectrum (EDS) and transmission electron microscope (TEM). The straight Y-groove test ...