The Experts below are selected from a list of 164883 Experts worldwide ranked by ideXlab platform
K. K. Kumar - One of the best experts on this subject based on the ideXlab platform.
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Effect of Zero-Vector Placement in a Dual-Inverter Fed Open-End Winding Induction-Motor Drive With a Decoupled Space-Vector PWM Strategy
IEEE Transactions on Industrial Electronics, 2008Co-Authors: V T Somasekhar, S. Srinivas, K. K. KumarAbstract:An open-end winding induction-motor drive with two two-level inverters achieves three-level inversion. The drawback of this configuration is the presence of a high zero-sequence current, stressing the semiconductor switching devices and the motor. To avoid this, two isolated dc power supplies are needed to feed individual inverters. In this paper, it is shown that it is possible to operate this drive with a single dc power supply, with reasonable engineering compromises. The new decoupled space-vector-based pulsewidth modulation (PWM) strategy proposed in this paper achieves this objective. This PWM strategy exploits the dependence of the zero-sequence voltage on the placement of the zero-vector of individual inverters. It is shown that the zero-sequence voltage of the dual-inverter system is suppressed by forcing the zero-sequence voltage of the individual inverters to a value of zero, in the average sense, in each sampling-Time interval. This strategy, therefore, achieves a dynamic balancing of the zero-sequence current. It is also shown that this PWM scheme achieves the center spacing of Effective-Time Period for the dual-inverter drive and its associated advantages. In addition, the effect of the placement of the zero-vector for individual inverters on the dual-inverter drive is investigated, and the experimental results are presented.
Somala S N - One of the best experts on this subject based on the ideXlab platform.
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Triple Pendulum Bearing Subjected to Simulated Near-Fault Ground Motions: Influence of Length (Directivity) and Speed (Supershear) of Rupture Propagation on Fragility
2021Co-Authors: Panguluri Suvarna, Somala S NAbstract:Base isolation is one of the widely used earthquake mitigation techniques, where the demands on the structure are reduced by introducing a flexible layer between sub-structure and super-structure. Many types of isolators are used in practice and the most commonly used isolator till now is Lead Rubber bearing. Triple pendulum isolator is slightly newer concept and research is still in progress on this. In order to control displacement at large earthquakes higher damping is provided so that performance of a building is not met in service earthquake. Triple pendulum is a solution to this problem due to its adaptive behavior. In any Base-Isolation system design, the important parameter is fixing the Time Period of isolation system where we have to decide upon the amount of base-shear that we want to design our superstructure for and the displacement at base we need to provide keeping in mind the utilities. To find the optimal Effective Time Period, a graph is drawn between Effective Time Period, isolator displacement, and base shear transferred to structure, by choosing coefficient of friction values and assuming a displacement and using an iterative process
Niyatie Ammanamanchi - One of the best experts on this subject based on the ideXlab platform.
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neuregulin stimulation of cardiomyocyte regeneration in mice and human myocardium reveals a therapeutic window
Science Translational Medicine, 2015Co-Authors: Brian D Polizzotti, Balakrishnan Ganapathy, Stuart Walsh, Sangita Choudhury, Niyatie AmmanamanchiAbstract:Therapies developed for adult patients with heart failure have been shown to be inEffective in pediatric clinical trials, leading to the recognition that new pediatric-specific therapies for heart failure must be developed. Administration of the recombinant growth factor neuregulin-1 (rNRG1) stimulates regeneration of heart muscle cells (cardiomyocytes) in adult mice. Because proliferation-competent cardiomyocytes are more abundant in growing mammals, we hypothesized that administration of rNRG1 during the neonatal Period might be more Effective than in adulthood. If so, neonatal rNRG1 delivery could be a new therapeutic strategy for treating heart failure in pediatric patients. To evaluate the Effectiveness of rNRG1 administration in cardiac regeneration, newborn mice were subjected to cryoinjury, which induced myocardial dysfunction and scar formation and decreased cardiomyocyte cell cycle activity. Early administration of rNRG1 to mice from birth to 34 days of age improved myocardial function and reduced the prevalence of transmural scars. In contrast, administration of rNRG1 from 4 to 34 days of age only transiently improved myocardial function. The mechanisms of early administration involved cardiomyocyte protection (38%) and proliferation (62%). We also assessed the ability of rNRG1 to stimulate cardiomyocyte proliferation in intact cultured myocardium from pediatric patients. rNRG1 induced cardiomyocyte proliferation in myocardium from infants with heart disease who were less than 6 months of age. Our results identify an Effective Time Period within which to execute rNRG1 clinical trials in pediatric patients for the stimulation of cardiomyocyte regeneration.
V T Somasekhar - One of the best experts on this subject based on the ideXlab platform.
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Effect of Zero-Vector Placement in a Dual-Inverter Fed Open-End Winding Induction-Motor Drive With a Decoupled Space-Vector PWM Strategy
IEEE Transactions on Industrial Electronics, 2008Co-Authors: V T Somasekhar, S. Srinivas, K. K. KumarAbstract:An open-end winding induction-motor drive with two two-level inverters achieves three-level inversion. The drawback of this configuration is the presence of a high zero-sequence current, stressing the semiconductor switching devices and the motor. To avoid this, two isolated dc power supplies are needed to feed individual inverters. In this paper, it is shown that it is possible to operate this drive with a single dc power supply, with reasonable engineering compromises. The new decoupled space-vector-based pulsewidth modulation (PWM) strategy proposed in this paper achieves this objective. This PWM strategy exploits the dependence of the zero-sequence voltage on the placement of the zero-vector of individual inverters. It is shown that the zero-sequence voltage of the dual-inverter system is suppressed by forcing the zero-sequence voltage of the individual inverters to a value of zero, in the average sense, in each sampling-Time interval. This strategy, therefore, achieves a dynamic balancing of the zero-sequence current. It is also shown that this PWM scheme achieves the center spacing of Effective-Time Period for the dual-inverter drive and its associated advantages. In addition, the effect of the placement of the zero-vector for individual inverters on the dual-inverter drive is investigated, and the experimental results are presented.
G A Karim - One of the best experts on this subject based on the ideXlab platform.
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an experimental and analytical examination of the combustion Period for gas fuelled spark ignition engine applications
Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2001Co-Authors: Bade S O Shrestha, G A KarimAbstract:AbstractA predictive procedure is described for determining the Effective Time Period needed to complete the energy release by combustion from the moment of flame initiation by a spark to the completion of flame propagation in a spark ignition engine while using a number of gaseous fuels and some of their mixtures. These predicted values of the combustion Period when used in a relatively simple modelling procedure can produce predicted values of key engine performance parameters that compare well with the corresponding experimentally obtained values.
