Precise energy eigenvalues of metastable bound doubly excited 1,3Fe states originating from 2 pnf(n=4–6)configuration of helium-like ions(Z=2–4)under weakly coupled plasma(WCP)environment have been estimated within ...Precise energy eigenvalues of metastable bound doubly excited 1,3Fe states originating from 2 pnf(n=4–6)configuration of helium-like ions(Z=2–4)under weakly coupled plasma(WCP)environment have been estimated within the framework of Ritz variational method.The wavefunction is expanded in explicitly correlated Hylleraas type basis set.The screened Coulomb potential is consideredas mimic the WCP environment.The atomic systems tend towards gradual instability and the number of excited metastable bound states reduces with increasing plasma strength.The wavelengths corresponding to 2 pnf(1,3F^e)→2 pnf(1,3Do)(n=4–6;n′=3–6)transitions occurring between doubly excited states of plasma embedded two-electron ions are also reported.展开更多
A new 4-node quadrilateral flat shell element is developed for geometrically nonlinear analyses of thin and moderately thick laminated shell structures. The fiat shell element is constructed by combining a quadrilater...A new 4-node quadrilateral flat shell element is developed for geometrically nonlinear analyses of thin and moderately thick laminated shell structures. The fiat shell element is constructed by combining a quadrilateral area co- ordinate method （QAC） based membrane element AGQ6- II, and a Timoshenko beam function （TBF） method based shear deformable plate bending element ARS-Q12. In order to model folded plates and connect with beam elements, the drilling stiffness is added to the element stiffness matrix based on the mixed variational principle. The transverse shear rigidity matrix, based on the first-order shear deformation theory （FSDT）, for the laminated composite plate is evaluated using the transverse equilibrium conditions, while the shear correction factors are not needed. The conventional TBF methods are also modified to efficiently calculate the element stiffness for laminate. The new shell element is extended to large deflection and post-buckling analyses of isotropic and laminated composite shells based on the element independent corotational formulation. Numerical re- sults show that the present shell element has an excellent numerical performance for the test examples, and is applicable to stiffened plates.展开更多
Power system faults can often result in excessively high currents.If sustained for a long time,such high currents can damage system equipment.Thus,it is desirable to operate the relays in the minimum possible time.In ...Power system faults can often result in excessively high currents.If sustained for a long time,such high currents can damage system equipment.Thus,it is desirable to operate the relays in the minimum possible time.In this paper,a busbar splitting approach is used for adaptive relay setting and co-ordination purposes for a system integrity protec-tion scheme(SIPS).Whenever a fault occurs,the busbar splitting scheme splits a bus to convert a loop into a radial structure.The splitting schemes are chosen such that the net fault current is also reduced.Busbar splitting elimi-nates the dependency upon minimum breakpoints set(MBPS)and reduces the relay operating time,thus making it adaptive.The proposed methodology is incorporated into the IEEE 14-bus and IEEE 30-bus systems with single and multiple fault conditions.The modeling and simulation carried out in ETAP,and the results of the proposed busbar splitting-based relay co-ordination are compared with the MBPS splitting-based relay co-ordination.展开更多
基金Supported under Grant No. EMR/2017/000737 from DST-SERB, Govt. of India, Grant No. 23(Sanc.)/ST/P/S&T/16G-35/2017 from DHESTB, Govt. of West Bengal, Indiaby the DHESTB,Govt.of West Bengal,India under Grant No.249(Sanc.)/ST/P/S&T/16G-26/2017
文摘Precise energy eigenvalues of metastable bound doubly excited 1,3Fe states originating from 2 pnf(n=4–6)configuration of helium-like ions(Z=2–4)under weakly coupled plasma(WCP)environment have been estimated within the framework of Ritz variational method.The wavefunction is expanded in explicitly correlated Hylleraas type basis set.The screened Coulomb potential is consideredas mimic the WCP environment.The atomic systems tend towards gradual instability and the number of excited metastable bound states reduces with increasing plasma strength.The wavelengths corresponding to 2 pnf(1,3F^e)→2 pnf(1,3Do)(n=4–6;n′=3–6)transitions occurring between doubly excited states of plasma embedded two-electron ions are also reported.
文摘A new 4-node quadrilateral flat shell element is developed for geometrically nonlinear analyses of thin and moderately thick laminated shell structures. The fiat shell element is constructed by combining a quadrilateral area co- ordinate method （QAC） based membrane element AGQ6- II, and a Timoshenko beam function （TBF） method based shear deformable plate bending element ARS-Q12. In order to model folded plates and connect with beam elements, the drilling stiffness is added to the element stiffness matrix based on the mixed variational principle. The transverse shear rigidity matrix, based on the first-order shear deformation theory （FSDT）, for the laminated composite plate is evaluated using the transverse equilibrium conditions, while the shear correction factors are not needed. The conventional TBF methods are also modified to efficiently calculate the element stiffness for laminate. The new shell element is extended to large deflection and post-buckling analyses of isotropic and laminated composite shells based on the element independent corotational formulation. Numerical re- sults show that the present shell element has an excellent numerical performance for the test examples, and is applicable to stiffened plates.
文摘Power system faults can often result in excessively high currents.If sustained for a long time,such high currents can damage system equipment.Thus,it is desirable to operate the relays in the minimum possible time.In this paper,a busbar splitting approach is used for adaptive relay setting and co-ordination purposes for a system integrity protec-tion scheme(SIPS).Whenever a fault occurs,the busbar splitting scheme splits a bus to convert a loop into a radial structure.The splitting schemes are chosen such that the net fault current is also reduced.Busbar splitting elimi-nates the dependency upon minimum breakpoints set(MBPS)and reduces the relay operating time,thus making it adaptive.The proposed methodology is incorporated into the IEEE 14-bus and IEEE 30-bus systems with single and multiple fault conditions.The modeling and simulation carried out in ETAP,and the results of the proposed busbar splitting-based relay co-ordination are compared with the MBPS splitting-based relay co-ordination.
