In-Process Radiography of ARC Weld

In-process nondestructive evaluation of welds is of major importance for automated weld processing. Real-time evaluation of defect formation makes possible on-line rewelding and adjustment of process parameters. Measurements of physical parameters related to weld quality may also give information important for understanding the weld process and for improvements of weld quality. In this study we implement industrial radiography for real-time weld process monitoring and testing. X-ray penetrating radiation is used for volume observation in the welding pool and the heat-affected zone during the weld process. The advantages of such a technique are on-line testing of defect formation in the weld and the study of metal fusion and filler metal-base metal interaction, metal transfer and mass flow in the welding pool. This technique may also be used for post-service real-time remote testing of weld quality. By integrating automatic nondestructive inspection with an automatic process control system, unified manufacturing control and testing procedures can be developed. In this unit approach, the nondestructive system may be included as a part of the sensing system in the feedback loop of the process control. Research and development of such general concepts for remote weld process control using real-time radiography as a vision system was initiated in our laboratory under the sponsorship of the Edison Welding Institute

Closed-Loop Radiographic Process Control of ARC Welding

Two different approaches may be applied to the nondestructive evaluation of welds. The conventional one consists in the application of nondestructive inspection after welding. The second, new, approach is in-process nondestructive evaluation where the production and testing operations are integrated into a single procedure. In this combined approach information received from nondestructive evaluation may be used in feedback with other process parameters for process control. Such a concept gives a significant cost saving [1]. Because the non-destructive system is included as a part of the sensing system in the feedback loop of the process control the quality control is integrated with the process itself.</p

Bunyavirus requirement for endosomal K+ reveals new roles of cellular ion channels during infection

In order to multiply and cause disease a virus must transport its genome from outside the cell into the cytosol, most commonly achieved through the endocytic network. Endosomes transport virus particles to specific cellular destinations and viruses exploit the changing environment of maturing endocytic vesicles as triggers to mediate genome release. Previously we demonstrated that several bunyaviruses, which comprise the largest family of negative sense RNA viruses, require the activity of cellular potassium (K+) channels to cause productive infection. Specifically, we demonstrated a surprising role for K+ channels during virus endosomal trafficking. In this study, we have used the prototype bunyavirus, Bunyamwera virus (BUNV), as a tool to understand why K+ channels are required for progression of these viruses through the endocytic network. We report three major findings: First, the production of a dual fluorescently labelled bunyavirus to visualize virus trafficking in live cells. Second, we show that BUNV traffics through endosomes containing high [K+] and that these K+ ions influence the infectivity of virions. Third, we show that K+ channel inhibition can alter the distribution of K+ across the endosomal system and arrest virus trafficking in endosomes. These data suggest high endosomal [K+] is a critical cue that is required for virus infection, and is controlled by cellular K+ channels resident within the endosome network. This highlights cellular K+ channels as druggable targets to impede virus entry, infection and disease

Real-Time Radiographic Investigation of Weld Pool Depression

Real-time radiography has been utilized by us previously as a vision system in remote arc welding process monitoring [1]. Direct information on weld penetration extracted from real-time radiographic images of the solidified weld was used in feedback to adjust the welding conditions to maintain weld quality [2]. The disadvantage of this method is the time (and space) delay in extracting information on weld penetration which leads to the appearance of small weld areas with lack of penetration. In subsequent work weld penetration was controlled by the use of radiographic information on weld pool depression to eliminate the time delay thus providing feedback before weld solidification [3]. In this implementation the method was applied to control bead-on-plate weld penetration only with no weld joint involved. A weld made on a joint which must be filled by liquid metal during welding is more complicated than a bead-on-plate weld.</p

Weld Penetration Control with Radiographic Feedback on Weld Pool Depression

Recently [1,2], a method for remote arc weld process control using real-time radiography as a vision system was described. In this work information on weld quality extracted from real-time radiographic images was used in feedback to change welding conditions to maintain weld quality. Principal attention was given to automatic control of weld penetration [2]. The radiographic image was analyzed at some distance behind the welding pool where the weld became solidified. An early detection, from the image, of depth of weld penetration was performed and based on this information the welding current was adjusted automatically to obtain complete penetration. The time (and space) delay in extracting information on weld penetration leads to the appearance of small areas of weld with lack of penetration.</p

In-Process Radiography of ARC Weld

In-process nondestructive evaluation of welds is of major importance for automated weld processing. Real-time evaluation of defect formation makes possible on-line rewelding and adjustment of process parameters. Measurements of physical parameters related to weld quality may also give information important for understanding the weld process and for improvements of weld quality. In this study we implement industrial radiography for real-time weld process monitoring and testing. X-ray penetrating radiation is used for volume observation in the welding pool and the heat-affected zone during the weld process. The advantages of such a technique are on-line testing of defect formation in the weld and the study of metal fusion and filler metal-base metal interaction, metal transfer and mass flow in the welding pool. This technique may also be used for post-service real-time remote testing of weld quality. By integrating automatic nondestructive inspection with an automatic process control system, unified manufacturing control and testing procedures can be developed. In this unit approach, the nondestructive system may be included as a part of the sensing system in the feedback loop of the process control. Research and development of such general concepts for remote weld process control using real-time radiography as a vision system was initiated in our laboratory under the sponsorship of the Edison Welding Institute.</p

Closed-Loop Radiographic Process Control of ARC Welding

Two different approaches may be applied to the nondestructive evaluation of welds. The conventional one consists in the application of nondestructive inspection after welding. The second, new, approach is in-process nondestructive evaluation where the production and testing operations are integrated into a single procedure. In this combined approach information received from nondestructive evaluation may be used in feedback with other process parameters for process control. Such a concept gives a significant cost saving [1]. Because the non-destructive system is included as a part of the sensing system in the feedback loop of the process control the quality control is integrated with the process itself.</p