F Mousavi, , A Majd, S Airian,
Volume 10, Issue 4 (2-2011)
Abstract
Ailanthus altissima (tree of heaven) belongs to Simaroubaceae. It is a dioecious plant and its flowers are unisexual, but there are unfertile reproductive organs of opposite sex rudimentarily. In this study, the structure of flower and pollen grain and anther development especially in staminate flowers were studied using light and scanning electron microscopes. Results showed that each staminate flower contained 10 functional stamens and 5 sterile carpels without ovule and embryo sac. Pistillate flowers produce a gynocium with 3-5 carpels (mostly 5 carpels) and 10 abortive stamens without pollen sacs and pollen grains. The anther wall in staminate flowers is composed of epidermis, endothecium, 2-3 middle layers and glandular tapetum. Tapetal layer is multinucleate and elongate. The cytokinesis following meiosis is simultaneous, producing tetrahedral and rhomb- shaped tetrads. Under SEM, pollen grains seems prolate, elliptic, isopolar and tricolporate. Exine sculpture is straite- reticulate.
Mahmoud Lotfi Honyandari, S. Mohammad Hosseini,
Volume 14, Issue 2 (7-2014)
Abstract
In recent decades optimal control problems with partial differential equation constraints have been studied extensively. These issues are very complex and the numerical solution of such problems is of great importance. In this article we will discuss the solution of elliptic optimal control problem. First, by using the finite element method we obtain to gain the discrete form of the problem. The obtained discrete problem is actually a large scale constrained optimization problem. Solving this optimization problem with traditional methods is difficult and requires a lot of CPU time and memory. But split Bergman method converts the constrained problem to an unconstrained problem, and hence it saves time and memory requirement. We then use the split Bregman iterative methods for solving this problem, and examples show the speed and accuracy of split Bregman iterative methods for solving this type of problems. We also use the SQP method for solving the problem and compare with split Bregman method.
