Fractional fourier domain encrypted holographic memory by use of an anamorphic optical system

We propose and demonstrate a fractional Fourier domain encrypted holographic memory using an anamorphic optical system. The encryption is done by use of two statistically independent random-phase codes in the fractional Fourier domain. If the two random-phase codes are statistically independent white sequences, the encrypted data are stationary white noise. We exploit the capability of an optical system to process information in two dimensions by using two different sets of parameters along the two orthogonal axes to encode the data. The fractional Fourier transform parameters along with the random-phase codes constitute the key to the encrypted data. The knowledge of the key is essential to the successful decryption of data. The decoding of the encoded data is done by use of phase conjugation. We present a few experimental results.     

Indolo[3,2-b]carbazole-based poly(arylene ethynylene)s through Sonogashira coupling for optoelectronic and sensing applications

Two indolo[3,2-b]carbazole (ICZ)-based polymers have been designed and synthesized using Sonogashira cross-coupling based on dibromoindolo[3,2-b]carbazoles and 2,7-diethynylfluorene or 9,10-diethynylanthracene. The 2, 8 positions of the ICZ moiety has been used for the bridging of arylene ethynylene structure to form the polymer backbone. The characterization has been done by Fourier transform infrared, proton nuclear magnetic resonance, ultraviolet–visible and (UV–vis) fluorescence spectroscopic methods. The polymers, moderately soluble in aprotic and chlorinated solvents, have been found to possess thermal stability above 300°C. The band gap examinations, executed through cyclic voltammetry and complemented by UV–vis studies, indicated their semiconducting nature and the possibility for their utilization for the fabrication of polymer solar cells and for optical switching applications. Interestingly, the new diethynylindolocarbazole systems have been found to act as Bronsted acid sensors as well as a Hg²⁺ receptors. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46940     

Bayesian Subset Model Selection for Time Series

Abstract.  This paper considers the problem of subset model selection for time series. In general, a few lags which are not necessarily continuous, explain lag structure of a time-series model. Using the reversible jump Markov chain technique, the paper develops a fully Bayesian solution for the problem. The method is illustrated using the self-exciting threshold autoregressive (SETAR), bilinear and AR models. The Canadian lynx data, the Wolfe's sunspot numbers and Series A of Box and Jenkins (1976) are analysed in detail.     

Stochastic and Dynamic Shipper Carrier Network Design Problem

The focus of this work is to determine the optimal storage capacity to be installed on transhipment nodes by shippers in a dynamic shipper carrier network under stochastic demand. A two stage linear program with recourse formulation is developed where in the first stage, the shipper decides the optimal capacity to be installed on transhipment nodes. In the second stage, the shipper chooses a routing strategy based on the realized demand. The performance of the following solution methods: Stochastic L Shaped Method, Regularized Decomposition and L Shaped Method with preliminary cuts were compared for various network sizes and numerous demand scenarios. A novel capacity shifting heuristic was introduced to generate a feasible implementable solution which significantly improves the performance of Regularized Decomposition and provides the best performance in the cases tested. Various ways of generating analytical bounds on the objective function value was discussed. The new capacity shifting heuristic was found to be efficient in generating tight upper bounds. Even though the formulation considered in this paper is for a single commodity, the model can be easily extended to account for multiple commodities.     

Rheological Properties of Certain Processed Rice Products

Two popular rice products, namely expanded rice and flaked rice, are prepared from parboiled rice. As about 90% dry weight of milled rice is starch, the behaviour of rice and its products reflects largely the behaviour of its starch. The above precooked rice products which undergo a high degree of thermal and/or mechanical treatment during processing have a high degree of gelatinization and display therefore properties like those of pregelatinized starch. Both expanded rice and flaked rice have high water binding capacity and cold-swelling properties. Under suitable moisture conditions they undergo retrogradation and show reduced hydration and viscosity. Normal steam-parboild rice shows much lower viscosity because of a comparatively low degree of starch gelatinization during processing and its subsequent retrogradation. Rheologically the cold slurry of these products indicates a thixotropic system demonstrating time dependent thinning. Further, a dependence on slurry concentration and degree of processing and a yield value behind a certain concentration were also apparent. The cold swelling properties of flaked rice and expanded rice show potential use of their flour as a possible subsitute for pregelatinized starch in food and other industries.     

Model reduction for discrete time systems

A modified approach for reducing the order of discrete time systems is presented. The objective of the reduction process is to preserve specific design parameters of the transfer function such as phase margin, gain margin, and bandwidth. This approach is attractive because it can be easily implemented and does not involve any complex algebra.<>     

The effect of the annealing of electrode films on the electrical resistivity of thin aluminium films

The resistance of aluminium films, coated on glass substrates with annealed and unannealed thick films of gold, silver, copper and aluminium as electrodes, was measured. The percentage variation in resistance of the aluminium films differs with the use of annealed and unannealed electrodes. This variation was found to be greater for gold, silver and copper electrodes and not very marked for aluminium electrodes. The respective roles of factors such as oxide formation and alloying at the film-electrode junction are discussed by considering the observed variation in the resistance of the films. An attempt is also made to correlate this variation with the microscopic features seen at particular electrode-film junctions.