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101.
102.
Gautam Dasgupta 《Acta Mechanica》2014,225(1):309-330
In any high-quality viscoplastic calculation, the objectivity related to shape and constitutive parameter indifference is desirable, especially when a continuous deformation into concavity is tracked. In the physical x?y frame, quadratic displacement vectors—explicitly coupled via Poisson’s ratio—encompass bar and Euler–Bernoulli beam modes. Analytically, the unique set of shape functions yields nodal loads and the element stiffness matrix from its area and the first and second area moments. Closed-form Mathematica results exhibit full compliance with all requirements of Iron’s patch tests. 相似文献
103.
104.
Silver metal has been synthesized in form of a finely divided loose nanopowder, 10–30 nm particle sizes, using a simple polyol process. In hot water, polymer molecules of polyvinyl alcohol (PVA) induce Ag+ → Ag reaction as a weak reducer (suitable to control the final particle size), forming a nanofluid of Ag nanoparticles in situ dispersing in part of PVA molecules. Ag nanoparticles do not aggregate much when casting a viscous Ag–PVA nanofluid (hot) onto a substrate in thin laminates or films. Freestanding Ag–PVA films could be obtained of 1–5 mm thickness after drying at room temperature. Dried sample can be easily peeled from a silicate glass substrate. As small as 5–10 mm Ag–PVA pieces were heated in air in order to recollect Ag nanoparticles by burning off the polymer. At 300–400 °C, Ag–PVA disintegrates and encounters combustion in air, resulting in a pure Ag-powder. As analyzed by X-ray diffraction, a single crystalline phase of an Fm3m cubic crystal structure formed. Lattice parameter a = 0.4071 nm and density ρ = 10.61 g/cm3 compare well the bulk values a = 0.4086 nm and ρ = 10.50 g/cm3. 相似文献
105.
Energy efficiency for gas liquid mixing in a modified downflow bubble column reactor has been analyzed in this paper. Efficiencies of the different parts of the bubble column have been assessed on the basis of energy dissipation. Prediction of the energy dissipation coefficient as well as energy utilization efficiency due to gas‐liquid mixing as a function of different physical, geometric and dynamic variables of the system has been done by correlation method. The distribution of energy utilization in the different zones of the column has also been analyzed. Experiments were carried out with air‐water and air‐aqueous solutions of carboxy methyl cellulose with different concentrations. 相似文献
106.
107.
A polymer composite of Ag-metal reinforced polyvinyl alcohol (PVA) is synthesized in shape of thin laminates of 200–300 μm
thickness. The process involves a chemical Ag+ dispersion in PVA and in-situ
reduction-reaction with active PVA molecules under hot conditions (with stirring) in water at 60–70°C temperature. The product
results in a metal Ag-polymer complex dispersed in the solution. After evaporating part of water, a derived viscous solution
is casted (in hot conditions) in shape of a thin laminate in a glass mould. In addition to chemical reducer, active OH-groups
(free from H-bonding) in PVA molecules of refreshed surfaces act as head groups to adsorb Ag+ and drive a directional
growth. Short fibrils of Ag-metal thus occur in reaction over the PVA molecules. Casting thin laminates from a liquid sample
Ag-PVA allows the fibrils (also the polymer molecules) to align along the surface. Selected Ag-contents up to 5.0 wt.% in
Ag-PVA laminates are studied in terms of scanning electron micrograph, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction.
Average size, morphology and aspect ratio (ϕ) vary in Ag-metal depending on the Ag-content. As long Ag-metal fibrils as 2–5 μm,
ϕ=35, occur in a sample of 2.0 wt.% Ag. The Ag-metal reflects in two characteristic 3d5/2 and 3d/3/2 XPS bands of 368.3 and 374.1 eV respectively. 相似文献
108.
109.
Poly(2-hydroxyethylmethacrylate) chains were grafted onto the backbone of agar using a microwave assisted method involving a combination of microwave irradiation and ceric ammonium nitrate to initiate the grafting reaction. The synthesized graft copolymers were characterized by intrinsic viscosity measurements, Fourier transform infrared spectroscopy, elemental analysis (C, H, N, O and S) and scanning electron microscopy. Ag-g-P(HEMA)-2 showed a much higher flocculation efficacy than agar. The optimized dosage of flocculation for Ag-g-P(HEMA)-2 in the wastewater was found to be 0.75 ppm. Compared to agar, Ag-g-P(HEMA)-2 was found to considerably reduce the pollutant load in the wastewater. 相似文献
110.
Amit B. Rajput Seikh J. Rahaman Gautam Sarkhel Manoj K. Patra Sampat R. Vadera Pravin M. Singru Yusuf Yagci Narendra N. Ghosh 《应用聚合物科学杂志》2013,128(6):3726-3733
A simple method for the preparation of magnetic nanocomposites consisting of cobalt ferrite (CF; CoFe2O4) nanoparticles, polybenzoxazine (PB), linear low‐density polyethylene (LLDPE), and linear low‐density polyethylene‐g‐maleic anhydride (LgM) is described. The composites were prepared by the formation of benzoxazine (BA)–CF nanopowders followed by melt blending with LLDPE and the thermal curing of BA. The composites were characterized by X‐ray diffraction, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, universal testing machine measurement, and vibrating sample magnetometry. The composites consisting of LLDPE, PB, and LgM (47.5L–47.5PB–5LgM) exhibited a higher tensile strength (23.82 MPa) than pure LLDPE and a greater elongation at break (6.11%) than pure PB. The tensile strength of the composites decreased from 19.92 to 18.55 MPa with increasing CF loading (from 14.25 to 33.25 wt %). The saturation magnetization of the composites containing 33.25 wt % CF was 18.28 emu/g, and it decreased with decreasing amount of CF in the composite. The composite films exhibited mechanical flexibility and magnetic properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献