Parameter Mismatches and Perfect Anticipating Synchronization in bi-directionally coupled external cavity laser diodes

We study perfect chaos synchronization between two bi-directionally coupled external cavity semiconductor lasers and demonstrate for the first time that mismatches in laser photon decay rates can explain the experimentally observed anticipating time in synchronization.Comment: Latex 4 page

A simple method to reduce torque ripple and mechanical vibration in direct torque controlled permanent magnet synchronous motor

The Direct Torque Control (DTC) technique of Permanent Magnet Synchronous Motor (PMSM) receives increasing attention due to its simplicity and robust dynamic response compared with other control techniques. The classical switching table based DTC presents large flux, torque ripples and more mechanical vibrations in the motor. Several studies have been reported in the literature on classical DTC. However, only limited studies that actually discuss or evaluate the classical DTC. This paper proposes a simple DTC method / Switching table for PMSM, to reduce flux and torque ripples as well as mechanical vibrations. In this paper two DTC schemes are proposed. The six sector and twelve sector methodology is considered in DTC scheme I and DTC scheme II, respectively. In both DTC schemes a simple modification is made in the classical DTC structure that is by eliminating two level inverter available in the classical DTC is replaced by three level Neutral Point Clamped (NPC) inverter. To further improve the performance of the proposed DTC scheme I, the available 27 voltage vectors are allowed to form different groups of voltage vectors such as Large - Zero (LZ), Medium - Zero (MZ) and Small - Zero (SZ), where as in DTC scheme II, all the voltage vectors are considered to form a switching table. Based on these groups, new switching table is proposed. The proposed DTC schemes are comparatively investigated with the classical DTC and existing literatures from the aspects of theory analysis and computer simulations. It can be observed that the proposed techniques can significantly reduce the flux, torque ripples, mechanical vibrations and improves the quality of current waveform compared with traditional and existing methods

Inverse Anticipating Synchronization

We report a new type of chaos synchronization:inverse anticipating synchronization, where a time delay chaotic system can drive another system in such a way that the driven system anticipates the driver by synchronizing with its inverse future state. We extend the concept of inverse anticipating chaos synchronization to cascaded systems. We propose means for the experimental observation of inverse anticipating chaos synchronization in external cavity lasers.Comment: LaTex 6 pages, resubmitted to PR

Lag time and parameter mismatches in synchronization of unidirectionally coupled chaotic external cavity semiconductor lasers

We report an analysis of synchronization between two unidirectionally coupled chaotic external cavity master/slave semiconductor lasers with two characteristic delay times, where the delay time in the coupling is different from the delay time in the coupled systems themselves. We demonstrate for the first time that parameter mismatches in photon decay rates for the master and slave lasers can explain the experimental observation that the lag time is equal to the coupling delay time.Comment: LaTex, 5 pages, submitted to PRE(R

Anticipated synchronization in coupled inertia ratchets with time-delayed feedback: a numerical study

We investigate anticipated synchronization between two periodically driven deterministic, dissipative inertia ratchets that are able to exhibit directed transport with a finite velocity. The two ratchets interact through an unidirectional delay coupling: one is acting as a master system while the other one represents the slave system. Each of the two dissipative deterministic ratchets is driven externally by a common periodic force. The delay coupling involves two parameters: the coupling strength and the (positive-valued) delay time. We study the synchronization features for the unbounded, current carrying trajectories of the master and the slave, respectively, for four different strengths of the driving amplitude. These in turn characterize differing phase space dynamics of the transporting ratchet dynamics: regular, intermittent and a chaotic transport regime. We find that the slave ratchet can respond in exactly the same way as the master will respond in the future, thereby anticipating the nonlinear directed transport

Cost-effective valorization of cassava fibrous waste into enantiomerically pure D-lactic acid: Process engineering and kinetic modeling approach

Cassava fibrous waste (CFW) valorization on the synthesis of D (-) lactic acid (DLA) holds enormous importance, particularly in the production of thermostable and biodegradable polymers. In this study, microbial kinetic modelling was carried out to investigate the dynamics of cassava fibrous waste enzyme hydrolysate (CFWEH) utilization towards DLA production. Designed biomass approach was attempted to evaluate the natural DLA producing organisms, capable of metabolizing CFWEH into optically pure DLA. Sporolactobacillus inulinus (NBRC 13595) was found to be the elite strain, resulting the yield of 99.43 % optically pure DLA using CFWEH-supplemented medium. Yeast extract (2 gL −1) was observed to be potential nitrogen source over other complex nitrogen sources for kinetic modelling investigation. Kinetic parameters predicted from the proposed model for DLA production showed maximum specific growth rate, - 0.36 (h−1); growth-associated product coefficient ( gg −1) and specific productivity ( gg −1h−1) respectively. Experimental data of biomass growth, substrate consumption and DLA production with initial sugar concentrations ranging from 20–180 gL −1 was found to be synchronized well with the simulated dynamic profiles. Kinetic investigation reported in this study is a novice attempt enumerating the valorization potential of CFW for the synthesis of value-added products including DLA at commercial scale in near future

Buck-boost single-stage microinverter for building integrated photovoltaic systems

Microinverters for Building Integrated Photovoltaic (BIPV) systems must have had a small number of components, be efficient, and be reliable. In this context, a single-phase Buck-Boost Single-stage Microinverter (BBSM) for grid-connected BIPV systems is presented. The concept of topology is extracted from the buck-boost converter. The leakage current in the system is kept under control. It uses an optimal number of active and passive components to function at a high-efficiency level. The suggested topology provides a high level of reliability due to the absence of shoot-through problems. To validate the findings, a simulation in combination with an experimental system for a 70 W system is developed with the design approach. The efficiency of the microinverter, total harmonic distortion of the grid current are measured as 96.4% and 4.09% respectively. Finally, a comparison study has indicated the advantages and disadvantages of the suggested inverter

Systems design of a high resolution retinal prosthesis

Simulations of artificial vision suggest that 1000 electrodes may be required to restore vision to individuals with diseases of the outer retina. In order to achieve such an implant, new technology is needed, since the state-of-the-art implantable neural stimulator has at most 22 contacts with neural tissue. Considerable progress has been made towards that goal with the development of image processing, microelectronics, and polymer based MEMS. An image processing system has been realized that is capable of real-time implementation of image decimation and filtering (for example, edge detection). Application specific integrated circuits (ASICs) have been designed and tested to demonstrate closed loop power control and efficient microstimulation. A novel packaging process has been developed that is capable of simultaneously forming communication coils, interconnects, and stimulating electrodes