PENGARUH PANJANG SALURAN TRANSMISI TERHADAP TEGANGAN LEBIH TRANSIENT YANG DISEBABKAN KARENA PROSES ENERGIZED PADA SALURAN TRANSMISI 500 KV

Yuniarto, in this paper explain that the utility of high transmission line result in the transient over voltage in transmission-line will also increasingly higher, mainly for lightning and switching surge. Switching surge is a dominant factor to show up much transient over voltage in the transmission-line in the level of 230 kV or higher, if it is compared with lightning surge. Switching surge is caused by single energized process, the process itself to energize a transmission line in no load condition with energy power through switch closure operation. The research was aiming at observing the influence of transmission-line length to transient over voltage that occurred at the energized process in 500 kV transmission line Ungaran-Pedan, which used EMTP (Electromagnetic Transients Program) to simulate it. The result of simulation showed that the transient over voltage occurred along the transmission-line which caused the higher voltage increase, providing that the line is also longer. Key word : over voltage, transient, EMTP

Electro-Magnetic Research of NEMS Beam and Cofferdam Structure with Porous Materials

We theoretically analyzed the microwave NEMS (Nano- micro- electronic mechanical systems) porous substrate materials and relevant characteristic to NEMS functions to achieve the balance of high performance and the low-cost. And the introduction of the micro fluidic cofferdam development was given at a Glance. ANSYS software was applied on NEMS beam switch simulation. The comparison result was drawn: the threshold voltage of the NEMS beam switch closure increases with metal Young's modulus of the material increases.

Sensitivity to novel feedback at different phases of a gymnotid electric organ discharge

SUMMARY Weakly electric fish communicate and electrolocate objects in the dark by discharging their electric organs (EOs) and monitoring the spatiotemporal pattern of current flow through their skin. In the South-American pulse-type gymnotid fish these organs often are intriguingly complex, comprising several hundreds of electrogenic cells (electrocytes) of various morphologies,innervation patterns and abilities to generate a spike, distributed over nearly the full length of the fish. An attractive idea is that different parts of the organ may serve distinct functions in electrocommunication and electrolocation. Recent studies support this notion and suggest that the currents produced during the final phase of the electric organ discharge (EOD)are used for communication. Here, we explore a method to directly assess the relevance of the various currents for electrolocation. In this new method, the pattern of current flow during a gymnotid EOD is changed selectively at distinct phases of the EOD so that currents generated by known electrocyte groups are affected. We have studied the roles played by the various currents for the detection of novel feedback at the trunk/tail region of the gymnotid fish Gymnotus carapo. An experimental animal rested in a cage and two electrodes were placed at a close distance to its trunk and tail. An electronic switch briefly connected these electrodes during a selected phase within an EOD and the shunting of EOD current that resulted from switch closure was directly monitored. G. carapo responded with an acceleration of its discharge rate to novelties in the EOD feedback that occurred only for a fraction of a single EOD. Controls in which the switch was closed during the silent intervals between successive EODs showed that the fish responded to the changes in EOD feedback and not to unrelated artefacts of the brief switch closure. Fish responded to shunting of current during all phases; the sensitivity was highest during the final headnegative phase but the magnitude of shunted current was largest in the preceeding phase. The current produced during the final part of the EOD is thus not reserved for communication as previously suggested but plays a predominant role in electrolocation at the trunk and tail region of G. carapo.