This article explores a number of existing project cost estimation techniques to investigate how the estimation can be done in a more accurate and effective manner. The survey looks into various estimation models that utilize many theoretical techniques such as statistics, fuzzy logic, case-based reasoning, analogies, and neural networks. As the essence of conventional estimation inaccuracy lies in life cycle cost drivers that are unsuitable to be applied across the project life cycle, this study introduces a phase-wise estimation technique that posits some overhead and latency costs. Performance evaluation methods of the underlying phase-wise principle are also presented. Contributions of this phase-wise approach will improve the estimation accuracy owing to less latency cost and increase the project visibility which in turn helps the project managers better scrutinize and administer project activities.
The technology of biodesulfurization requires that reactors, where the reaction can take place, must be designed. In order to do this, the kinetics of the process must be thoroughly understood. This work aims to investigate the kinetics of biodesulfurization of diesel. This was done by simulating the kinetics of the process alone and then with and without the effect of mass transfer. The kinetic parameters, maximum rate constant, νmax, and the Michaelis-Menton constant, KM, were estimated using the linear equations of Hanes, Lineweaver-Buck and Eadie-Hofstee. The values obtained for each of the parameters from the linear equations were close but are not the same. This necessitated the need to carry out a non-linear regression analysis on the substrate concentrationtime data. The analysis was done using Marquardt’s algorithm of non-linear regression analysis. The obtained results were then compared with experimental data, they both showed good correlation with the experimental data although the mass transfer influenced kinetics showed a better agreement with the experimental data. Based on the aforementioned findings, one may conclude that mass transfer played an important role in the kinetics of biodesulfurization of diesel.
Young, H.D.; and Freedman, R.A.; Ford, A.L. (contributing author). 2012. Sears and Zemansky’s University Physics with Modern Physics. 13th ed.Pearson Education, Inc., Addison-Wesley, San Francisco, CA, USA.
