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Solid-state Li-ion batteries with lithium anodes offer higher energy densities and are safer than conventional liquid electrolyte-based Li-ion batteries. However, the growth of lithium dendrites across the solid-state electrolyte layer leads to the premature shorting of cells and limits their practical viability. Here, using solid-state Li half-cells with metallic interlayers between a garnet-based lithium-ion conductor and lithium, we show that interfacial void growth precedes dendrite nucleation and growth. Specifically, void growth was observed at a current density of around two-thirds of the critical current density for dendrite growth. Computational calculations reveal that interlayer materials with higher critical current densities for dendrite growth also have the largest thermodynamic and kinetic barriers for lithium vacancy accumulation at their interfaces with lithium. Our results suggest that interfacial modification with suitable metallic interlayers decreases the tendency for void growth and improves dendrite growth tolerance in solid-state electrolytes, even in the absence of high stack pressures.

The rapid spreading of the coronavirus in India and its behaviour for the near future has been studied and analysed as accurately as possible using the SEIR model as a fundamental tool. The official covid-19 data of infected and death cases in India upto 10th October, 2020 have been considered as raw data. The value of various parameters of the model is optimised by feeding the raw data in the simulation model. The various parameters are defined as infection rate, basic reproduction number, death rate, recovery time, exposure time, and other parameters to optimise the best fit model. The total population of India is considered 1.36 billion people. The simulation results that the number of recovered people will be 2.8 × 108and number of deaths will be 4.2 × 106after 800 days for the total population of India. In an ideal scenario, at the end of the pandemic total death count is expected to be of the order of 106which is a big challenge.

The twisted light beams carry orbital angular momentum (OAM), which acts as additional degrees of freedom. In this work, we have proposed a free space optics (FSO) communication system employing wavelength division multiplexing (WDM), OAM multiplexing, and four-level pulse amplitude modulation (PAM-4) techniques. A 1600 Gbps data has been successfully transmitted over free space in different environmental scenarios such as clear weather, weak turbulence, moderate turbulence, and strong turbulence. The effects of atmospheric turbulence on the PAM-4 signals carrying OAM modes are examined theoretically and simulated for the first time. Optical frequency comb lines are generated by employing a single laser source and used as a broadband laser source. A sufficient low power penalty of 1.489 dB at a BER value ∼ 10-9along with clear eye diagrams has been achieved for the proposed system. Thus, the proposed 1600 Gbps PAM-4, OAM, and WDM-based system can be a promising solution for the next generation of long-reach and high-data-rate free-space communication.

A noteworthy scheme to transport dual band 10 Gbps 16 quadrature amplitude modulated orthogonal frequency division multiplexed signal for downlink and uplink channel over 55 km single mode fiber as well as 650-m free space is proposed and demonstrated. Moreover, noise tolerance against Rayleigh backscattering, that arises in bidirectional transmission system is enhanced as different bands of subcarrier are used for uplink and downlink transmission in our proposed system. Negligible power penalty (<1 dB), good bit error rate value (under FEC limit i.e. 3.8 × 10−3), proper error vector magnitude (<12.35%) and signal to noise ratio (>19 dB under FEC limit) marks the reliability of the proposed design. We observed that dual band subcarrier modulation scheme is able to decrease large power penalty (~8 dB) for total transmission link. The results from our proposed network makes it more potent to give an alternative platform with long reach, less noise, high data rate transmission which is the top most thirst to the upcoming generation.