A rotating two-phase gas/liquid flow regime for pressure reduction in underwater plasma arc welding

Plasma arc welding processes are used in the off-shore industry for construction and maintenance of underwater structures and pipelines in a wet environment. At greater water depths the density of the plasma gas increases because of the greater hydrostatic pressure. This causes conductive heat losses to the wet environment to increase. To maintain the energy flux to the workpiece to be welded, the plasma arc has to burn in a local dry area with an inside pressure of 1 bar. This requirement can be fulfilled by a rotating cylinder with a liquid film flowing down the inner wall. The flow around the rotating cylinder is experimentally investigated. The rotating cylinder is placed above the work surface which is simulated by a flat plate. Because of the centrifugal forces of the rotating flow inside the gap between the lower end of the cylinder and the flat plate the water is forced out of the cylinder. The velocity distribution in the flow is measured by laser Doppler anemometry. The phase distribution in the two-phase flow in the gap is measured by local electrical probes. The static pressure inside the gaseous atmosphere is reduced in comparison to the hydrostatic pressure of the surrounding water. The pressure reduction is given by the void fraction, the phase distribution and the volume flow rates of both phases in the gap as well as by the speed of revolution and the design of the cylinder and the work surface. The influence of these parameters on heat transfer from the workpiece to the two-phase flow regime is also investigated.     

Process assessment with a project focus

The author compares three process assessment techniques that measure improvement against the Software Engineering Institute's capability maturity model (CMM), particularly the Computer Science Corporation's software process audit method. The Software Engineering Institute has developed two approaches to determine an organization's process maturity: software process assessments (SPA) and software capability evaluations (SCA), both of which use the SEI's CMM as a yardstick. Computer Science Corporation's software process audit method addresses the major limitations of the SPA, ie. SPAs occur too infrequently to track progress; SPA results are reported at the organization, not project level; and SPAs direct process improvement at the organizational level. The process-audit approach at CSC focuses on projects, specifically their conformance to the organization's defined process. As such, a process audit fits between a SPA and an SCE     

Dynamic monocular machine vision

A new approach to real-time machine vision in dynamic scenes is presented based on special hardware and methods for feature extraction and information processing. Using integral spatio-temporal models, it by-passes the nonunique inversion of the perspective projection by applying recursive least squares filtering. By prediction error feedback methods similar to those used in modern control theory, all spatial state variables including the velocity components are estimated. Only the last image of the sequence needs to be evaluated, thereby alleviating the real-time image sequence processing task.This research has been partially supported by the German Federal Ministry of Research and Technology (BMFT), the Deutsche Forschungsgemeinschaft (DFG), the Daimler-Benz AG, and by Messerschmitt-Bölkow-Blohm GmbH (MBB).     

Phase I trial of the thioether phospholipid analogue BM 41.440 in cancer patients

The online version of the original article can be found at     

Fuzzy techniques and user modeling in Sales Assistants

Uncertainty and fuzziness are ubiquitous in the field of computerized selling. Therefore the mastery of these domains might be a key factor for the success of electronic selling. In this paper the Sales Assistant is introduced. It employs user models in the problem solving and dialog control layers, and fuzzy techniques for the management of imprecision. Fuzzy Multiple Criteria Analysis has proven its usefulness in product evaluation if there are no severe interdependencies among the product attributes. The user model in the Sales Assistant is constructed unobtrusively on the basis of user behavior, and it uses short-term information. It increases the transparency and usability of a large hypertext-like information system.