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A game-theoretic approach to analyse inter-modal competition between high-speed rail and airlines in the Indian context
No full textIn this paper, a game-theoretic framework is applied in order to model the competition scenario between high-speed rail (HSR) and airlines in the Indian context and assess the impact of speed and passengers' characteristics on the equilibrium of the game. The competition is modelled in terms of the fare and frequency offered by the operators to maximize their profits. The speed of HSR is taken as an additional strategic variable in the game with three levels of high speed: low, medium, high. A three-stage game is formulated with the entrant playing its speed strategy in the first stage followed by optimal fare and frequency selection by both the modes. Passengers are considered to be heterogeneous in nature by assuming a continuous distribution of the value of time. Numerical simulations indicate that the dominant strategy for airlines and HSR is based on accommodation and medium speed, respectively
Direct Detection of Bacteria Using Positively Charged Ag/Au Bimetallic Nanoparticles: A Label-free Surface-Enhanced Raman Scattering Study Coupled with Multivariate Analysis
No full textRapid detection and discrimination of pathogenic bacteria for food safety, environmental pollution, medical diagnoses, and chemical and biological threats remains a considerable challenge. In the present work, we demonstrate positively charged Ag/Au bimetallic nanoparticles (Ag/Au bmNPs) as a potential surface-enhanced Raman scattering (SERS) substrate for label-free detection and discrimination of three bacteria, viz., Escherichia coli, Salmonella typhimurium, and Bacillus subtilis with excellent reproducibility. The approach relies on a priori synthesis of Ag/Au bmNPs and subsequent SERS studies on bacteria. The positive surface charge on Ag/Au bmNPs offers significant advantages of short acquisition time at very low power, high sensitivity, and a simple operating procedure without the need of very specific procedures or protocols used to capture the bacteria. The reproducible and specific intrinsic fingerprint of the cell wall and intracellular components of three bacteria obtained by label-free SERS enables precise discrimination and classification of three bacteria using multivariate analyses such as principal component analysis and canonical discriminant analysis
Sub-diffraction resolution of periodic grating structures in a focus engineered sum frequency generation microscope
No full textUse of Toraldo-Type pupil phase masks in a nonlinear sum frequency generation microscope for subdiffraction resolution improvement is simulated. It is found that optimally chosen 0-w phase mask of diameter 64 of the full aperture results in reduction in the nonlinear focal field by 60 of the no phase mask case with 75 of energy concentrated in the central lobe. When imaging periodic grating structures, resonant enhancement and reversal of contrast are observed for grating pitch comparable to the diameter of the side lobes. The resonant contrast enhancement can potentially be used for selectively amplifying certain spatial frequencies in the sample
Quantized Variational Bayesian Joint Channel Estimation and Data Detection for Uplink Massive MIMO Systems with Low resolution ADCS
No full textIn this paper, we consider the joint channel estimation and data detection in an uplink massive multiple input multiple output (MIMO) receiver with low resolution analog to digital converters (ADCs). The nonlinearities introduced by the ADCs make the existing linear multiuser detection (MUD) approaches suboptimal, and motivates a fresh look at the problem. Also, channel state information is necessary to obtain the channel quality metrics that are used for link adaptation by the base station (BS). We model the MIMO receiver system as a directed probabilistic graphical model, and propose a variational Bayesian procedure to estimate the channel and the posterior beliefs of the transmitted symbols. We evaluate the symbol error probability (SEP) and the normalized mean squared error (NMSE) of the channel estimates of the proposed algorithm using Monte Carlo simulations, and benchmark it against an unquantized variational Bayesian algorithm with perfect and imperfect channel state information at the receiver (CSIR)
Stochastic Approximation Trackers for Model-Based Search
No full textIn this paper, we propose multi-timescale, sequential algorithms for deterministic optimization which can find high-quality solutions. The algorithms fundamentally track the well-known derivative-free model-based search methods in an efficient and resourceful manner with additional heuristics to accelerate the scheme. Our approaches exhibit competitive performance on a selected few global optimization benchmark problems
Observation of second harmonic generation from multilayer Tin diselenide
No full textWe report spatially resolved second harmonic generation from a multilayer tin di-selenide (\mathrmS\mathrmn\mathrmS\mathrme-2) flake using a nonlinear optical microscopy setup. The second order nonlinear signal from \mathrmS\mathrmn\mathrmS\mathrme-2\ \mathrmi\mathrms∼ 21 times weaker than that of quartz substrate. Tin di-selenide is expected to exhibit centrosymmetric lattice arrangement with vanishing second-order nonlinear optical effects. The observed second order nonlinear effects from multi-layer \mathrmS\mathrmn\mathrmS\mathrme-2 is ascribed to lattice distortions
Phylogenetic diversity as a measure of biodiversity: Pros and Cons
No full textSpecies richness is predominantly used as one of the fundamental measures of biodiversity for prioritization of areas for conservation. However, species richness often underestimates true diversity, as it does not take into account the evolutionary histories of the species in an area. In this regard, phylogenetic diversity, which incorporates information regarding species relationships in calculating diversity, has been proposed as an alternative. Here we compare species richness and phylogenetic diversity of mammals in nine sanctuaries to explore the importance and use of evolutionary relationships in characterizing diversity. Our analyses suggest that even though species richness and phylogenetic diversity are correlated, they are often decoupled. Importantly, areas with low species richness might harbour high phylogenetic diversity and vice-versa. We recommend the use of both the diversity measures for a holistic understanding of biodiversity and for prioritization of areas for conservation
Design of pre-diffuser cones for dump diffusers for aero gas turbine engines
No full textThe main concern of any dump diffuser designer is to design the geometry to achieve the highest possible static pressure recovery within the given envelop of the aero gas turbine engine. In this paper design optimization of dump diffusers with three multiple-steps pre-diffuser divergent cones with the aerodynamically-shaped flame tube have been performed using a validated density based steady standard k-ε turbulence model. The code is validated using the exact solution obtained from the closed-form analytical model of V.R. Sanal Kumar (AIP Advances, 8, 025315, 2018) at the Sanal flow choking condition. This is the continuation of our previous AIAA paper (AIAA 2016-5009). We observed that the boundary layer displacement thickness at the pre-diffuser upstream port is having an effect on the static pressure recovery in the dump diffuser. We also observed that the static pressure recovery can be increased profitably during the flight by designing a dump diffuser with adjustable dump gap facilitated with multiple-steps pre-diffuser cones. We concluded that the dump diffuser with geometrically optimized pre-diffuser upstream port and its divergent cone along with the aerodynamically-shaped adjustable flame tube for attaining variable dump gap effect is a profitable and viable option for improving the performance characteristics of aero gas turbine engines under a wide range of operating conditions. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA
Magnetic, ferroelectric, and magnetodielectric properties of BiFeO3 ceramic co-doped with Eu and Gd
No full textPolycrystalline samples of Bi0.9Eu0.1FeO3, Bi0.9Gd0.1FeO3, and Bi0.9Eu0.05Gd0.05FeO3 ceramics were synthesized by a solid-state reaction method, followed by rapid quenching to room temperature. Bio(0.9)Eu(0.1)FeO(3) shows higher magnetization than Bi0.9Gd0.1FeO3 and Bi5.9Eu0.05Gd0.05FeO3. This can be explained by lattice distortion, and the change in the statistical distribution of Fe3+ /Fe2+. Similarly, ferroelectric polarization of Bi0.9Eu0.1FeO3 was found to be higher than that of Bi0.9Gd0.1FeO3 and Bi0.9Eu0.05Gd0.05FeO3. However, the absolute value of the magnetocapacitance of Bi0.9Eu0.05Gd0.05FeO3 (similar to 1.6%) was found to be higher than that of Bi0.9Eu0.1FeO3 (similar to 1.3%) and Bi0.9Gd0.1FeO3 (similar to 1.1%). In addition, the quadratic component of magnetoelectric coupling is higher for Bi0.9Eu0.05Gd0.05FeO3, which makes Bi0.9Eu0.05Gd0.05FeO3 attractive for further study
In situ preparation of multicomponent polymer composite nanofibrous scaffolds with enhanced osteogenic and angiogenic activities
No full textBioactive ceramics are extensively used for bone repair and regeneration, which release ions to initiate apatite formation and promote osteogenic differentiation eventually resulting in strong bonding to bone. Toward enhancing the bioactivity of polymeric nanofibrous scaffolds, this work presents a one-step in situ sol-gel method to fabricate electrospun composite nanofibrous scaffolds encapsulating well dispersed ceramic nanoparticles overcoming the limitations of current preparation techniques. Transmission electron micrographs revealed uniform distribution of ceramic nanoparticles within the polymer nanofibers. The multicomponent scaffolds were found to release calcium, silicon and phosphate ions that mimic the dissolution and bioactivity of conventional bioactive glasses. The scaffolds enhanced the bioactivity of PCL fibers as observed through enhanced apatite formation in simulated body fluid. The released ions markedly enhanced the proliferation and osteogenic differentiation of human mesenchymal stem cells and the angiogenic activity of human endothelial cells in vitro. This work has important implications for engineering the next-generation nanostructured scaffolds that exhibit multi-biofunctional activities for bone tissue regeneration