Experience with shipyard installation of a hybrid pipe welding system
Laser-Gas Metal Arc (GMA) hybrid welding is fast making the transition from laboratory to production, in industries as diverse as shipbuilding to automobile manufacture. For the past 3 years, our team has striven to both develop a hybrid welding process for steel pipe, and to specify, build, and install a hybrid pipe welding system in a General Dynamics NASSCO shipyard. In March 2007, the system was successfully installed into the shipyard. This work presents a summary of our continued experimental explorations into various practical aspects of hybrid welding, discusses the system design, and provides an overview of the installation of the system into the shipyard. Test results are presented, as well as lessons learned throughout the project.
Arc augmented laser processing of materials
It has recently been found that an electric arc can be added to the interaction between a laser beam and a material surface in such a way that in welding and cutting it produces an effect similar to that from a more powerful laser. The experimental results are discussed together with an analysis of the process mechanism. In particular it appears that the arc strikes the work piece at the same interaction zone as the laser, and in so doing undergoes a contraction in width to near the same size as the laser beam. It also seems probable that some of the arc energy penetrates the laser generated keyhole. So far the experimental results have shown that arc augmentation of the laser by some 2 kW of arc power in the work piece can be achieved without unduly spoiling the high quality of the cut or weld that would be made by a laser alone of similar total power.
Acetylation analysis of saccharides. 2. Microanalysis of neutral glycosphingolipids by means of acetylation with radioactive acetic anhydride.
Abstract The quantitative analysis of mixtures of glycosphingolipids by acetylation with radioactive acetic anhydride and separation by thin-layer chromatography is described. The method was primarily developed for screening of glycosphingolipid composition of tissues, cultured cells, and virus preparations. The sensitivity and linearity of the method is demonstrated. Although theoretically a much higher sensitivity is achievable, in practive about 10 −9 g of glycosphingolipid can be detected and tentatively identified. As an example, the acetylation pattern of lipids from a preparation of herpes simplex virus is demonstrated.