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Smart superabsorbent UV resistant etherified PVA gel: Synthesis and characterization
Ayan Dey,Rabin Bera,Sabbir Ahmed,Debabrata Chakrabarty 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
Polyvinyl alcohol (PVA) is etherified with ethane-1,2-diol to obtain smart etherified polyvinyl alcohol(EPVA) having improved mechanical and gelling characteristics. Linear EPVA is deficient in swellingcompared to PVA and follows first order swelling kinetics. EPVA when converted to gel with 5%crosslinker (EPVA5) shows maximum swelling and mechanicals. Sustained solvent releasing ability ofthe EPVA gel is evident from the deswelling study. EPVA gels demonstrate an increase in storagemodulus with increase in crosslinker dose. Ultraviolet resistance ability of the EPVA gel is maximum inthe UV range of 280–320 nm. EPVA5 exhibits cells of nanometric dimensions.
Ayan Das,Raj Purohit Kiran,Sahil Bansal 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.87 No.1
The paper presents a Bayesian Finite element (FE) model updating methodology by utilizing modal data. The dynamic condensation technique is adopted in this work to reduce the full system model to a smaller model version such that the degrees of freedom (DOFs) in the reduced model correspond to the observed DOFs, which facilitates the model updating procedure without any mode-matching. The present work considers both the MPV and the covariance matrix of the modal parameters as the modal data. Besides, the modal data identified from multiple setups is considered for the model updating procedure, keeping in view of the realistic scenario of inability of limited number of sensors to measure the response of all the interested DOFs of a large structure. A relationship is established between the modal data and structural parameters based on the eigensystem equation through the introduction of additional uncertain parameters in the form of modal frequencies and partial mode shapes. A novel sampling strategy known as the Metropolis-within-Gibbs (MWG) sampler is proposed to sample from the posterior Probability Density Function (PDF). The effectiveness of the proposed approach is demonstrated by considering both simulated and experimental examples.
Ayan Kumar Sarkar,Anirban Manna,Sadhana M. Chatterjee,Alip Roy 한국지질과학협의회 2023 Geosciences Journal Vol.27 No.6
Previous work reveals a syn-tectonic granite named Phulad granite, which is emplaced (~820 Ma) in the western part of the South Delhi Fold Belt (SDFB) along and across the Phulad Shear Zone (PSZ). There is a lack of information about the detailed microstructural study, differential stress and strain rate variation from this granite body. These pieces of information are crucial in developing deformational history associated with the shear zone deformation. The granite preserves a variety of dynamic recrystallization from grain boundary bulging (BLG) to sub-grain rotation (SGR) to grain boundary migration (GBM). There is a variation in the fractal dimension (D) in the granite, such as higher D at the shear zone, and with increasing distance from the shear zone, D values are low. Strain rates (10−7.52 s−1–10−7.99 s−1) are much higher than the geological strain rates in the natural systems. The strain rates indicate that the method to calculate strain rate using the D value (1.007 ± 0.017 to 1.031 ± 0.022) is to some extent erroneous or fails to give geologically reasonable value for high-temperature syn-tectonic granite such as Phulad granite. Based on the quartz piezometer, our findings reveal variation in flow stress with distance from the shear zone, which depends on the grain size. Volume gain and mass balance calculations indicate that fluid incorporation at the shear zone reduces deformation temperature, which also validates the findings from the microstructural study. These microstructures and grain size calculations are discussed to interpret the deformation mechanism, various stress-strain pattern and evolution of the Phulad granite throughout the area.