KONTAMINASI MERKURI (Hg) DALAM ORGAN TUBUH IKAN PETEK (Leiognathus equulus) DI PERAIRAN ANCOL, TELUK JAKARTA

Mercury (Hg) which is contained in aquatic ecosystem can enter and be accumulated to organism’s body, like on petek fish (Leiognathus equulus). The research aimed to see mercury concentration in aquatic ecosystem, to see mercury concentration in organ of petek fish by AAS (Atomic Absorption Spectrophotometer) and its histopathology response in organs of petek fish. The research was done at Ancol, Jakarta Bay on October-December 2004. There are 16 samples of water and fish from 3 stations.The analysis result of water quality is compared by standard quality of sea water for sea organism life (Kepmen LH No. 51, 2004), mercu ry concentration in fish organ is compared by maximum mercury concentration in fish body by classification of Palar (2004). Ancol water quality is still on normal condition. Mercury concentration in water and petek fish organs had low concentration. Gill and lever contaminated by mercuryis only in station 1 fish, but it is still on normal concentration. Histopathology of petek fish gill is not abnormal, while the lever is necrosis. Water and petek fish is not a good indicator to detect mercury in aquatic ecosystem.Keywords: mercury, petek fish, water, lever, gill, histopathology, accumulation,indicator

Parameter Optimization of Steam Generator Feedwater Controller Based on Particle Swarm Optimization

The U-tube steam generator(SG), as the joint of primary and secondary circuits, is one of the crucial components in a PWR plant. Because of the swell-and-shrink phenomena, it is very difficult to control the water level of the steam generator. Presently the three-element controller in cascade configuration with two PID controller is widely use. But the determination of the six optimal PID parameters of the cascade controller is a major problem. This paper studies the application of the particle swarm optimization(PSO) methods in determining the parameters of cascade controller of SG water lever. The SG is modeled in Simulink and the PSO algorithm is implemented in MATLAB. Comparing with conventional PID parameter, the proposed method is more efficient in improving the step response characteristics while controlling the water level of SG.

Slope Stability Analysis under Drawdown Conditions Using Strength Reduction Technique Based on Fast Lagrangian Method

The stability of the slope under the conditions of drawdown quickly and drawdown gradually of water level is analyzed using strength reduction method based on fast Lagrangian method in three dimension. Results of study show that the method is feasible. For the slope on the side of river, the value of safety factor of the slope become less and less when the speed of drawdown of water lever become faster and faster. Thus, the working condition with the maximum speed of drawdown of water lever should be the controlling working condition for stability analysis of slope on the side of river. Furthermore, ratio of water depth and height of slope also has neglected impacts on the stability of slope and potential slip surface of slope under the condition of drawdown of water lever.

Stress Calculation of Gravity Dam Based on Elastic Mechanics

Based on the elastic mechanics theory, combined with Saint-Venant principle and the superposition principle, the calculating method for the stress of gravity dam in arbitrary storage water lever were put forward by means of the equivalent stress method and the dimensional analysis method through the conversion between a Cartesian coordinate system and Polar coordinate system. The method not only offers a new idea for calculating the stress of gravity dam, but also presents research bases for evaluating synthetically the strength of gravity dam.

Research on the Lowest Navigable Water Lever of Downstream of the Hydro-Junction

Taking the third and the fourth shiplock of the Changzhou Hydro-junction as an example, it analyses the variation of downstream water level and its influenced factors. It adopts a plane 2D mathematical model for total sand to simulate riverbed deformation and transferring law about water level drop from Jieshou to upstream. It estimates water level drop which caused by riverbed scouring and channel regulation engineering in the downstream of the Changzhou Hydro-junction. The lowest navigable water level is obtained. It could provide some technical support for design and new idea for studying similar problems.

The Simulation and Comparison of Synchronous and Serial Regulating Gates Method in the Emergency Status of Long Distance Water Project

For long distance water transmission project, choose a more effective control method is very import for safety and decrease loss in the emergency status. In the past, the serial regulate gate method is adopted oftentimes. However, its disadvantages are obvious, such as lower efficiency and rapid dropping speed of water lever which easily lead to landslide. This paper proposes a synchronous regulating gates method for emergency control which ensures the flow of open channel can reach new status of uniform flow in shortest time. The results of simulation show the dropping speed of water level using synchronous regulation method is significantly smaller than serial regulation method. The total time requires significantly less than serial regulation method too.