Papers by Keyword: Branch Length

Abstract: In this work, hydroforming of X-shape pipe connection made of copper is investigated by experiment and numerical simulation. The length of the connection branch is always a concern. The main purpose of the work is the study of the effect of the branch end boundary condition and the load path on the branch height. An elastic material (called the constraint), such as a spring, is used for controlling the branch to grow to a certain extent. It is shown that the branch end condition, if designed properly, gives rise to the considerable increase in the branch length. The increase, however, depends also on the load path which must be determined by experiment or numerical simulation.

Abstract: In this study, the sample data was based on 2190 branch length samples of 30 trees from dahurian larch (Larix gmelinii Rupr.) plantations located in Wuying forest bureau in Heilongjiang Province. A second order polynomial equation with linear mixed-effects was used for modeling branch length of larch tree. The LME procedure in S-Plus is used to fit the mixed-effects models for the branch length data. The results showed that the polynomial model with three random parameters could significantly improve the model performance. The fitted mixed effects model was also evaluated using mean error, mean absolute error, mean percent error, and mean absolute percent error. The mixed model was found to predict branch length better than the original model fitted using ordinary least squares based on all errors. The application of mixed branch length model not only showed the mean trends of branch length, but also showed the individual difference based on variance-covariance structure.