BIDDING ON PROJECTS BASED ON PREVIOUS WORKS AND EMINENCE, A CONTRACTORS' VIEW POINT

Nowadays, a project-winning environment is very competitive. In order to be successful and make profit, a contractor should start planning in advance and decide about what projects to bid. A prominent contractor should bid on projects for which his chances of winning are good enough or on projects for which the profit is high enough such that bidding would be worth consuming the resources needed for preparing the bid. The chances of winning bids are related to many factors but among all, degree of eminence (previous works) and price are the most important. In this thesis we have developed an optimization model that maximizes an index that takes both of these factors into consideration. Genetic Algorithm is used to solve this optimization model.The output of this model is the most beneficial set of projects and their respected optimal bid markups that will help the contractor make the most intuitive selection which, in return, benefits him/her the most at present and in the future

Numerical Study of Forced Air Cooling of a Heated Porous Foam Pyramid array

The current study employs CFD to study the forced air cooling of a pyramid shaped porous foam absorber. Herein, a three by three (3×3) array of porous foam absorbers heated with an external heat flux is modeled using the differential equations governing heat and fluid flow through porous media based on the Brinkman-Darcy flow equations and an effective thermal conductivity to account for the porous medium. The numerical simulations are carried out using the COMSOL commercial Computational Fluid Dynamics (CFD) Finite Element based software package. The primary finding of our study is that the more porous the foam absorber media is, the more dependent the effective thermal conductivity is on the thermal conductivity of the fluid used for cooling. If the fluid is air, which has a very low thermal conductivity, the effective thermal conductivity is decreased as the porosity increases, thus diminishing removal of heat from the foam array via the cooling air stream. Based on the parametric study, the best case operating conditions which may allow the pyramidal foam absorber to stay within the max allowable temperature are as follows: porosity = 0.472, inlet air cooling velocity = 50 m/s