Prototyping Large-Sized Objects Using Freeform Thick Layers of Plastic Foam

Current Rapid Prototyping systems are primarily aimed at small-sized objects containing many shape details. In this paper a Rapid Prototyping technology is presented that is aimed at largesized objects having a complex, freeform outer shape. This new technology builds the model out ofthick layers, each having freeform outside faces. The paper will present: an overview of current methods to produce large prototypes, the basics of the new method, the technology used to produce the layers, the toolpath planning and finally the overall system design.Mechanical Engineerin

Strong Decays of Strange Quarkonia

In this paper we evaluate strong decay amplitudes and partial widths of strange mesons (strangeonia and kaonia) in the 3P0 decay model. We give numerical results for all energetically allowed open-flavor two-body decay modes of all nsbar and ssbar strange mesons in the 1S, 2S, 3S, 1P, 2P, 1D and 1F multiplets, comprising strong decays of a total of 43 resonances into 525 two-body modes, with 891 numerically evaluated amplitudes. This set of resonances includes all strange qqbar states with allowed strong decays expected in the quark model up to ca. 2.2 GeV. We use standard nonrelativistic quark model SHO wavefunctions to evaluate these amplitudes, and quote numerical results for all amplitudes present in each decay mode. We also discuss the status of the associated experimental candidates, and note which states and decay modes would be especially interesting for future experimental study at hadronic, e+e- and photoproduction facilities. These results should also be useful in distinguishing conventional quark model mesons from exotica such as glueballs and hybrids through their strong decays.Comment: 69 pages, 5 figures, 39 table

Partial wave analysis of the low-mass KÛÛ systems produced diffractively and by charge-exchange in 4.2 GeV/c K¯p interactions

Contains fulltext : mmubn000001_02654329x.pdf (publisher's version ) (Open Access)Promotor : E. Kittel109 p

New functionality for computer-aided conceptual design: the displacement feature

Conceptual design using conventional 3D CAD systems is a controversial issue among industrial designers. Although one can produce complex, accurate, finished 3D models using these CAD systems, it is still difficult to use them during early, creative product design. In this paper, a method is described that allows the design of protrusions and depressions in sculptured surfaces in a flexible and interactive manner. Through interviews with industrial designers, the basic requirements for support of such functionality during conceptual design have been formulated. An implemented method based upon these requirements has been extensively evaluated by industrial designers, and these evaluations show that industrial designers find this functionality extremely useful during conceptual shape design.

Towards computer-supported inclusion and integration of life cycle processes in product conceptualization based on the process tree

Development of computer support in design is showing several shifts in focus over the latest decades. This paper relates to the shifts from detail design to conceptualization, from artifact geometry definition only to the inclusion of process knowledge, and from isolated aspects to integrated aspects. It discusses a possible solution for simultaneous consideration of life cycle process aspects during conceptual design using the process tree representation. Integrating process aspects can be considered a preparation for an integrated representation of artifact and process aspects to be used in a front-end environment for conventional CAD detailing systems

Using adaptive ruled layers for Rapid Prototyping: principles and first results

Current 2.5D layered rapid prototyping has as disadvantage the staircase effect, requiring thin layers to be used to achieve a reasonable accuracy. Slices with inclined outer surfaces can be constructed using linear interpolation between adjacent contours, resulting in ruled slices. A methodology to approximate a given model geometry within a specified accuracy using ruled slices and an adaptive layer thickness is described. This involves matching successive contours and analysing the geometry for curvature and inclination to calculate allowed layerthicknesses. First results show a significant reduction in the number of layers when compared to adaptive slicing using 2.5D layers. A proof-of-concept software, the Delft University of Technology Improved Slicer (DUTIS) has been developed to perform the adaptive slicing using either 2.5D or ruled layers allowing a comparison between the two alternative methods.Mechanical Engineerin