[en] Highlights: • Degradation of MCMB-LMO coin cells examined by cycling of full- and half-cells. • Model considers dissolution, solid-electrolyte interface film and gas evolution. • Cell parameters measured and used to study capacity fade through simulations. • Experiments and simulations identify higher capacity loss in MCMB electrode. - Abstract: The electrochemical performance of mesocarbon microbeads (MCMB)-lithium manganese oxide (LMO) spinel cells is examined by cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy. The loss in capacity in full-cells is attributed to occurrence of parasitic reactions at the two electrodes. The contribution of each electrode in full-cell degradation is ascertained through testing of MCMB and LMO half-cells, with the former exhibiting a faster rate of degradation as compared to the latter. Lithium diffusion coefficient of MCMB and LMO electrodes are determined using the galvanostatic intermittent titration technique at various stages of cycling. The experimentally measured parameters are used to simulate the electrochemical behavior of MCMB and LMO half-cells. The computed capacity and cell potential variation show good agreement with experimentally obtained data for half-cells at 1C and 2C currents. The MCMB half-cell simulations reveal that loss in discharge capacity occurs due to thickening of SEI film, increase in gas formation and loss in cyclable lithium. Simulations of LMO half-cells show that capacity loss with cycling is a result of reduction in active material, increase in surface resistance with inactive material deposition and loss in cyclable lithium.

[en] Multi-Weyl semimetals (WSMs) are characterized by anisotropic non-linear dispersion along a 2-D plane and a linear dispersion in an orthogonal direction. They have topological charge 'n' and are produced when two or multiple Weyl points or nodes with nonzero net monopole charge are brought together onto a high-symmetry point. Studied here is a perturbation corrections up to second order of such multi-WSMs in crossed electric (E) and magnetic (B) fields in the low electric field approximation. As a consequence, the n-fold degeneracy of the lowest Landau levels is lifted while the higher one remains unaffected due to the first order perturbation. The higher Landau levels are modified due to the second order perturbation while lowest Landau levels remain unaffected. The signatures of these corrections of electric fields on the density of states (DOS) subjected to a magnetic field have been studied

[en] The nuclear weapons and ballistic missile tests conducted by India and Pakistan in the late 1990s substantially altered the security environment, both in the region and globally. Examining the complexities, and dynamics of this new strategic context, this timely and significant book examines the claim of many Indian strategists that stability in the region is better served under conditions of declared-rather than covertly developed-nuclear weapons. Bringing together original essays by a diverse group of scholars, this volume discusses a number of important issues such as: the political considerations that caused India and Pakistan to go nuclear; the type of nuclear doctrine that is likely to emerge and its implications for the safety of nuclear weapons, the potential for an arms race in the region, and the likelihood of war; the political and economic consequences for India after Pokhran-II and the impact of economic sanctions; the technological ramifications of the nuclear program on India's defence science scenario; the impact of these tests on the future of India's relationship with the United States, the main bulwark against nuclear weapons proliferation, also, the changed role that India sees for itself in international fora; the possible arms control measures that might succeed in stabilizing the South Asian nuclear rivalry. This insightful, comprehensive and topical volume is a must-read for all those in the fields of political science, international relations, strategic affairs, conflict/peace studies, economics, and policy studies

[en] Free space optical (FSO) communication provides the capacity to deliver high-speed digital data links into the far off and rural factions where topography, set-up cost or groundwork safety pose acute barriers to deployment. The challenges in any FSO system are the transmission impairments and space loss which deteriorate the link performance. This article deals with the design and analysis of a single channel Gray-coded dual polarization-quadrature phase shift keying (DP-QPSK) based FSO communication system with balanced homodyne detection (BHD) and digital signal processing (DSP). We have implemented a series of high-level digital impairment compensation algorithms strategically between the BHD and signal retrieval stages to mitigate the amplitude and phase noise, and compensate for free-space loss. The proposed system exhibits a 3 dB greater receiver sensitivity using optical homodyne detection compared to heterodyne detection. The system performance has been numerically evaluated with regard to bit error rate (BER $\le <!--\; ???\; -->2\times <!--\; ??\; -->{10}^{-<!--\; ???\; -->3},$ i.e. FEC limit), error vector magnitude (EVM), and constellation diagram based on OptiSystem V.16 photonic software. Furthermore, we investigate the joint BER and EVM performance of the proposed system under the influence of launched optical power, laser linewidth, and beam divergence. We obtain the transmission of 32 GBaud DP-QPSK data bearing optical signal up to a link distance of 2.65 km at 128-Gb/s data rate, and an optical signal-to-noise ratio penalty lower than 2.5 dB compared to the back-to-back case. The outcomes of this research demonstrate direct practical relevance and could therefore form the basis for the implementation of next-generation optical wireless networks.

[en] End plug welding of Prototype Fast Breeder Reactor (PFBR) fuel elements involves welding of fully Austenitic Stainless Steel (ASS) of grade D9 clad tube with 316M end plug. Pulsed Gas Tungsten Arc Welding (GTAW) is being used for the production of PFBR fuel elements at Advanced Fuel Fabrication Facility (AFFF). GTAW is an established process for end plug welding and hence adopted by many countries. GTAW has got certain limitations like heat input, arc gap sensitivity and certain sporadic defects like tungsten inclusion. Experiments have been carried out at AFFF to use Laser Beam Welding (LBW) technique as LBW offers a number of advantages over the former process. This report mainly deals with the optimization of laser parameters for welding of PFBR fuel elements. To facilitate pulsed Nd-YAG laser spot welding, parameters like peak power, pulse duration, pulse energy, frequency and defocusing of laser beam on to the work piece have been optimized. On the basis of penetration requirement laser welding parameters have been optimized. (author)

[en] Advanced Fuel Fabrication Facility, BARC, Tarapur is engaged in the fabrication of MOX fuel elements of various reactors. Based on the experience gained, a glove-box line is set up for fabrication of PFBR fuel elements. This fabrication line is designed to meet the requirement of higher production rate of PFBR fuel elements. The typical problems encountered in the fabrication have been simplified by use of novel techniques, mechanization and automation

[en] Highlights: • Development of an improved single-particle model for high C-rate applications. • Effect of non-linear spatial distribution of electrolyte potential, overpotential and open-circuit potential incorporated, leading to significantly improved prediction of the cell voltage. • Ease of implementation for battery management systems as a linear system of differential-algebraic equations in state-variables need to be solved. • Criteria for series-truncation of a semi-analytical model for electrode particle diffusion proposed. • Model validated against pseudo-2D and improvement to previous reduced-order models demonstrated. -- Abstract: In this work, an isothermal, reduced-order polynomial-based model is proposed for lithium-ion cells. The correction incorporated into the single-particle model considers the effect of electrolyte dynamics leading to improved model predictions at high current applications without adding any significant computational complexity. The model includes the spatial distribution of the electrode and electrolyte potentials and the electrolyte lithium concentration on the resulting cell voltage. A novel approach to account for the spatially varying overpotential and open-circuit potential is proposed. A linear system of differential-algebraic equations is obtained in the state variables and the cell voltage is computed using a non-linear expression in these states. The resulting linear state-space system makes the model easily implementable for state-estimation algorithms in battery management system applications. Additionally, a semi-analytical model is incorporated for the diffusion of lithium in electrodes and a criterion for truncating the infinite-series solution is proposed for achieving a balance between accuracy and complexity for cells subjected to fluctuating currents. The proposed model results in a decrease in error for cell voltage prediction by a factor of five when compared with existing enhanced single-particle models.

[en] The underlying study investigates the artificial metamaterial designing of non-symmetric dual layer combination on the same substrate for the negative characteristics of refractive index, permittivity and permeability. The design is instigated with the investigation of single and dual layers metamaterial design for single or double negative behavior. Apart from the parametric study, the dispersion diagrams of the layers are also evaluated for gap and gapless transactions from left hand to right hand behavior. The combination of symmetric and non-symmetric layers is also analyzed for behavior change in material properties. The permittivity and permeability of the designed non-symmetric dual layer metamaterial are negative up to 10 GHz and are positive above 10 GHz. Moreover, the left and right hand impedance also remains unchanged and matched with that of free space impedance (377 Ω) with a fractional bandwidth of 50%. Hence, the designed material acts as a double positive material for high frequencies above 10 GHz and double negative material for low frequencies below 10 GHz. The design is verified using circuit modeling and full wave electromagnetic simulations. The results obtained are authenticated using the free space measurement method.

[en] The compact sized cross-shaped metamaterial design is evaluated for single negative, double negative and double positive behavior for a wide range of frequencies to investigate the gap and gapless transition from backward to forward wave propagation near 17 GHz. The metamaterial designed in this study is analyzed for negative index characteristics of permittivity, permeability and refractive index over the broad range of frequencies. The dispersion diagram of the material is also investigated for left or right behavior of the material. The equivalent circuit diagrams along with circuit simulations of the parameters are also presented for detailed analysis and understanding. The designed metamaterial behaves like a double negative material for low frequencies below 17.23 GHz and double positive materials for high frequencies above 17.23 GHz. The design is simulated using CST Microwave studio and obtained results are authenticated using the wave-guide measurement technique. (paper)

[en] Ion-exchange resin abbreviated as HBAE-I was synthesized. Abbreviation HBAE-I used for p-hydroxybenzaldehyde-adipic acid-ethylene glycolco-polymer inl:1:3 ratio. The IR, ¹H NMR spectrum areused for characterization. Ion-exchange properties found for Bi³⁺, Sb³⁺, Zn²⁺ and Mg²+ ionsover 4 to 6 pH range. Toxic and heavy metal ions such as Sb³⁺, Bi³⁺, Mg²⁺ and Zn²⁺ are present in industrial effluent and wastewaters. The HBAE-I terpolymer resin are a selective for Bi³⁺and Zn²⁺ metals ions at pH 4 and 6 respectively. (paper)