Nano fibrillated cellulose-based foam by Pickering emulsion: Preparation,characterizations, and application as dye adsorbent

An ecofriendly and biodegradable porous structure was prepared from drying aqueous foams based on nano fibrillated cellulose (NFC), extracted from softwood pulp by subcritical water/CO₂ treatment (SC-NFC). The primary aim of this work was to use the modified SC-NFC as stabilizer for a water-based Pickering emulsion which upon drying, yielded porous cellulosic materials, a good dye adsorbent. In order to exploit the carboxymethylated SC-NFC (CMSC-NFC, with a degree of substitution of 0.35 and a charge density of 649 μeqv/g) as a stabilizer for water-based Pickering emulsion in subsequent step, an optimized quantity of octyl amine (30 mg/g of SC-NFC) was added to make them partially hydrophobic. A series of dry foam structures were prepared by varying the concentrations of treated CMSC-NFCs and 4 wt% was found to be the optimum concentration to yield foam with high porosity (99%) and low density (0.038 g/cc) along with high compression strength (0.24 MPa), superior to the conventionally extracted NFC. The foams were applied to capture as high as 98% of methylene blue dyes, making them a potential green candidate for treating industrial effluent. In addition, the dye adsorption kinetics and isotherms were found to be well suited with second order kinetics and Langmuir isotherm models.     

Local jet pattern: a robust descriptor for texture classification

Multimedia Tools and Applications - Methods based on locally encoded image features have recently become popular for texture classification tasks, particularly in the existence of large intra-class...     

Transformation of sputtered calcium copper titanate thin film into nanorods by sequential annealing

Rapid synthesis of long calcium copper titanate (CCTO) nanorods was carried out by sequential annealing. CCTO thin films have been deposited on p-Si substrate by RF sputtering technique and afterwards, the samples were thermally treated using a preheated furnace by varying the annealing temperature from 850 °C to 1100 °C. CCTO nanorods of 12 µm lengths and 400–600 nm diameters were synthesized at 1100 °C. Based on the FESEM observations, a plausible growth mechanism has been proposed to explain the formation of nanorods. The (220) XRD peak of the CCTO film became prominent for the annealing temperature of 950 °C. The presence of nanoscale crystals in amorphous matrix has been observed by HRTEM studies. The elemental mapping of CCTO nanorod has shown a spatial variation of elements throughout the nanorod. The oxide and interface charge density was found to be increased with the rise in annealing temperature.     

Microstructure,hardness, toughness and abrasive wear resistance of 16.0 wt. % chromium white iron after continuous and cyclic destabilisation treatment

Destabilisation of as-cast chromium white iron with 16 wt-% chromium are performed by continuous destabilisation treatment for 4 h and short duration (0.66 h) cyclic destabilisation treatment at 900, 950, 1000, 1050, and 1100 °C. Continuous destabilisation causes secondary carbides precipitation from austenite which on slow cooling transforms to pearlite matrix. Cyclic destabilisation treatment causes similar precipitation of finer secondary carbides following shorter period austenitisation and a matrix containing martensite and retained austenite on forced-air cooling. After continuous destabilisation, hardness falls below the as-cast value (HV622); whereas it rises to HV950 after cyclic destabilisation treatment. The as-cast notched impact toughness (4.0 J) increases to 8.5 J or more after both continuous and cyclic destabilisation at 1050 and 1100 °C. Abrasive wear resistance after continuous destabilisation improves only at higher wear load (49.0 N), while after cyclic destabilisation it supersedes the as-cast and Ni-Hard IV performance at both low (19.6 N) and high (49.9 N) wear load.     

Aluminum to germanium inversion in mullite-type RAlGeO5: Characterization of a rare phenomenon for R = Y,Sm–Lu

Mullite-type RMn₂O₅ (R = Y, rare-earth element) ceramics are of ongoing research attentions because of their interesting crystal-chemical, physical, and thermal properties. We report a detailed structural, spectroscopic and thermal analysis of the series of mullite-type RAlGeO₅ (R = Y, Sm-Lu) phases. Polycrystalline samples are prepared by solid-state synthesis methods. Each sample is characterized by X-ray powder diffraction followed by Rietveld refinements, showing that they are isotypic and crystallize in the space group Pbam. The change of the metric parameters is explained in term of the lanthanide contraction effect. A rare inversion of Al/Ge between octahedral and pyramidal sites have been observed for these mullite-type so called O10 compounds, and the inversion parameter found to be between 0.22(1) and 0.30(1) for different R-cations. The <Al/Ge–O> bond distances and their bond valence sums (BVSs) support the respective inversions. Density functional theory (DFT) calculated phonon density of states (PDOS) and electronic band structures are compared for the vibrational and electronic band gap features respectively. Analysis of UV/Vis absorption spectra using both derivation of absorption spectra fitting (DASF) and Tauc's methods demonstrates that each of the RAlGeO₅ O10 compounds is high bandgap semiconductor, possessing direct transition between 4.1(1) and 5.4(1) eV. Both Raman and Fourier transform infrared spectra show clear red shift (quasi-harmonic) of the vibrational wavenumbers with respect to the ionic radii of the R-cations. Selective Raman bands at higher wavenumber region further complement the inversion of Al/Ge between two coordination sites. The higher decomposition temperature of the RAlGeO₅ compounds, compared to those of RMn₂O₅ phases, is explained in terms of higher bond strength of Al/Ge-O than those of Mn-O. Irrespective to the inversion between Al- and Ge-sites, the decomposition temperature also depends on the type of R-cation in RAlGeO₅.     

Samarium Ion-Doped Maghemite Nanoparticles: Synthesis,Microstructural, Optical,and Magnetic Characterizations

Journal of Superconductivity and Novel Magnetism - This paper reports the effects of rare-earth Sm3+ ion substitution on structural, optical, electronic, and magnetic responses of maghemite...