| 3 | Effect of poly(vinyl pyrrolidone)on the morphology and physical properties of poly(vinyl alcohol)/sodium montmorillonite nanocomposite films显示文摘Nanocomposites of poly(vinyl alcohol)(PVA),poly(vinyl pyrrolidone)(PVP) and sodium montmorillonite(Na^+MMT) were prepared by solution mixing and then cast into films.X-ray diffraction analysis and images of transmission electron microscopy establish the formation of PVA/Na^+MMT intercalated nanocomposite.Exfoliated and highly intercalated PVA/PVP/Na^+MMT nanocomposite formed in the presence of PVP.Inclusion of PVP in PVA/Na^+MMT matrix enhances the hydrogen bonding interactions between PVA and Na^+MMT and thus increases the mechanical properties and thermal stability of PVA/PVP/Na^+MMT nanocomposites compared to PVA/Na^+MMT nanocomposite.The interactions between PVA,PVP and Na^+MMT were established by the Fourier transform infrared spectroscopy.The moisture absorption tendency of both the PVA and PVA/PVP films reduced after the incorporation of Na^+MMT at 75%constant relative humidity.Differential scanning calorimetry studies show that the presence of PVP and Na^+MMT both are responsible for reducing the heat of fusion,and crystallinity of PVA.The flow behavior of the PVA,PVA/PVP and its nanocomposite solutions has been also studied.Water vapor permeability of PVA/PVP/Na^+MMT composite films decreased in the presence of nanoclay due to increasing tortuous paths for diffusion. | Dibyendu Mondal Md.Masud R.Mollick Biplab Bhowmick Dipanwita Maity Mrinal K.Bain Dipak Rana Asis Mukhopadhyay Kausik Dana Dipankar Chattopadhyay | 2013 | Progress in Natural Science:Materials International2013，23，6： | 0 |
| 4 | Palaeogeographic reconstruction of a fluvio-marine transitional system in Narmada rift basin, India——Implications on Late Cretaceous global sea-level rise显示文摘Rising sea-levels in tectonically active epicontinental basins often lead to varied depositional settings and palaeogeography, mostly influenced by the net accommodation resulting from mutual interference of the extent and nature of landward encroachment by the sea and the net sedimentation. The Cenomanian Nimar Sandstone Formation, Bagh Group, Narmada rift basin, uniquely portrays the effect of sea-level rise within an intra-cratonic setting and attributes to the corresponding palaeogeographic changes in west-central India. An integrated sedimentological–sequence-stratigraphic study of the broadly fining-upward Nimar Sandstone Formation(thickness~ 20–30 m) depicts the actual nature of changeover from a fluvial to a marine-dominated transitional depositional setting. Detailed sedimentological study reveals total seventeen facies, grouped in five facies associations, viz., the channel-fill facies association(FA-1), the overbank facies association(FA-2), the fluvial-dominated fluvio-tidal facies association(FA-3), the tide-dominated fluvio-tidal facies association(FA-4), and the shoreface facies association(FA-5). Overall facies architecture indicates a west-to-eastward marine encroachment, resulting in stacking of three distinct palaeo-depositional conditions:(i) an initial fluvial system with channel and overbank, changing into a tideinfluenced fluvial bay-head delta in the inner estuary, followed by(ii) marine encroachment leading to a tidedominated central estuary with inter-to sub-tidal settings, and finally,(iii) with further intense marine encroachments, a wave-reworked open shore condition in the outer estuary zone. The overall fining-up succession with a systematic change from fluvial to marine-dominated depositional systems points to a landward shift of the shoreline, signifying a major transgressive event correlated to the Cenomanian global sea-level rise. Characteristic stratal stacking patterns point to four coarsening-and fining-up hemicycles, embedded within the major transgressive succession. These high-frequency cycles attest to the varied interplay of sedimentation, tectonics and sea-level changes, and the resultant net accommodations. A palaeogeographic model is proposed based on the high-frequency transgressive–regressive hemicycles, which envisages the evolution of the depositional environments in relation to the Cenomanian eustatic rise in the intra-cratonic riftogenic fluvio-marine transitional basinal setup. | Biplab Bhattacharya Suparna Jha Prantik Mondal | 2021 | Journal of Palaeogeography2021，10，1： | 0 |
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