نشریه سد و نیروگاه برق آبی ایران
پیاپی 1 (بهار 1393)

The conventional approach of project management assumes the project manager face with regular and predictable environment. While features such as The large number of components, Interdependence between them, A high degree of synergy, Variety of components, and Above all, the nonlinear behavior, those the main characteristic of complex systems have caused the nature of construction projects appears quite differently than previous one. At first, Complexity is not usually a problem, but with its formation within the project structure and its development as a function of the project, Imbalances can easily occur and will make the situation of the project critical. In this situation, each key elements of project will call some agents as the condition changing agents. In such situations, the project managers, in addition to solve the complexity of project and provide necessary solutions, should be able to have the support of key stakeholders. However, in actual projects, project manager reasons have been illogical for supporters and even another part of project seem to be more important in their opinion. Indeed, many project sponsors have different understanding of the complexity of the project compare with project managers. The status will be escalated when the manager have to keep the project on time. Under this pressure, the project managers focus more toward the project. Project managers do not have any time to think about the environment or consider various possibilities. While from a system perspective, problems that can occur in systems usually have multiple causes. This study seeks to provide a conceptual framework for understanding the complexity of the project, first define the complexity and then introduce the construction project as a complex project. More ever, to have the same understanding of the project, common framework will be introduced and explained.

Liquid storage tanks are considered as a vital artery with high importance. Therefore, the dynamic behavior of liquid storage tanks should be investigated. In this study, At first, the verification of finite element method based on the result of scaled experimental tank with different dimensions of elements was done.Then, modal and time history analyses were conducted and the free surface sloshing was investigated. The results of different element types were compared with the experimental results used statistical program SPSS17. In the next step a concrete rectangular tank with 1000m3 capacity was studied with different dimension of elements. Finally, the time history of North ridge earthquake record was applied to 1000m3 tanks with two and three horizontal and vertical components and the result of this analysis was evaluated. The results of modal and time history analyses showed that the effect of dimension of elements on the response is considerable and modal analysis alone cannot validate the modeling of tanks with the finite element method and the dimensions of elements with ratio height to length larger than 1 did not show good agreement as well as the results of dynamic analyses showed that The presence of vertical earthquake ground motion in combination with horizontal ground motion do not have any significant effect on the sloshing behavior water in the tank. However, the vertical earthquake acceleration can have remarkable effects on the maximum hydrodynamic pressure, and its distribution on the tank walls.

Hydroelectric plants are responsible the important role to generate electricity in a country and horizontal intakes is usually used to transfer water from the reservoir, In dehydration time of dams reservoirs, a phenomenon called vortex lead to reduces the efficiency of power plant and destroys the equipments of power plant .The water depth at the lower level that the strongest vortex is formed is known as the critical submergence depth and during operation of the dams should be not dehydrated at levels less than the this depth. So consider the most important factors on the critical submergence depth are very important. The axial velocity in this study as one of the most effective hydrodynamic parameters on the critical submergence depth and the vortex has been investigated with assisting of experimental model of Siahbishe dam (1/20 model) and numerical model of vertical two dimensional and with using of Fluent software

Increasing the cement grout stability and reduction of its bleeding during grouting process is very important, especially in rocks with micro porosity that increase duration of grouting. For reducing the bleeding affect of cement grout and increasing penetrability grout into micro porosity of Gotvand dam formations, using of micro silica fume is offered in grout mix design. The results of lab mix design represent the effectiveness of micro silica fume

Iranian National Power Market (INPM) has been established and started since 2003 and one of the most concerning of hydropower is the INPM’s impact on the hydropower operation. According to Khuzestan Water and Power Authority (KWPA) data for Dez hydropower dam, it seems that the national dispatching center may order the operator of hydropower to increase generation of power sometimes. Results showed that in 2010 the amount of power generation based on the national dispatching center schedule for Dez hydropower weren’t matched with power generation plan of KWPA, as owner of Dez hydropower. This happened for 62% time duration of 2010. This caused to lose some water resources and the reservoir water surface level was decreased more than value obtained from rule curve operation. So in this paper, suitable guidelines has been discussed and suggested to matching the INPM and manager of KWPA power generation schedule.

Concept of Virtual Power Plant (VPP) can be used to aggregate Distributed Energy Resources (DER) units into restructured power systems. This paper presents an optimization model that provides optimal operating strategy and benefit maximization scheme as well as the reduction of the emission for a VPP. The VPP considered in this paper consists of a wind turbine, a CHP system, several DGs, and loads with curtailment options. VPP can be participated in wholesale power market as an entity with dual role including producer and consumer. The presented model is a nonlinear mixed-integer programming problem with constraints. In this problem, Objective function is VPP profit with aim supply both thermal and electrical energy demands. The results demonstrate the efficiency of the proposed approach to satisfy the demand and to reduce emissions.