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•Hexagonal, high aspect-ratio CoNi nanoplatelets were synthesized and mechanism of formation explained.•Effect of platelet orientation under shear and magneto-static forces was ...explained theoretically.•Two-step yielding were observed for the magnetic fluids with high volume fraction under high magnetic fields.•Structural disintegration of the formed aggregates under critical shear strain below and beyond the yield points.
In this paper, we discussed the structure and morphologies of monodispersed CoNi nanoplatelets synthesized by hydrothermal reduction. The growth mechanism of platelet-like nanoparticles from precursors were described with reference to the SEM analysis. We further studied the effect of polymer and surfactants on to the structure, surface and magnetic properties of the nanostructures. Furthermore, in order to emphasize a shape-rheology correlation, magnetorheological studies were performed with suspensions containing CoNi nanoplatelets for the concentrations ranging from 5 to 12 vol%. The effect of plate orientation under the oscillatory shear was also investigated and an interesting two-step yielding was observed for the magnetic fluids with high particle volume fraction and under high magnetic fields. This was explained in terms of magnetic structure disintegration under shear flow below and beyond the critical amplitude strain.
During the last decade, worldwide attention of researchers has focused on nano-ceramic composites with superior mechanical behavior and improved reliability for structural applications. Here we ...report the development of a multi-layer composite (MLC) of tape cast nano zirconia with high failure energy. The MLC samples were fabricated by thermocompression of green tapes prepared from 3 mole % yttria stabilized zirconia (3-YSZ) powder with a primary crystallite size of 27 nm. Depending on the number of layers, the MLC samples exhibited failure energy (238.97 KJm
−3
) more than two times higher than that of the single tape (≈107 KJm
−3
) with a reasonably high bi-axial flexural strength (≈630 MPa), high hardness (≈ 13 GPa at 49 N), and indentation fracture toughness nearly four times as high as that of the single tape. In addition, these MLC materials showed the presence of a R-curve behavior.
In the present investigation efforts were made to study mechanically driven structural transformation in Sn reinforced Al–Cu–Fe icosahedral quasicrystalline (IQC) matrix nanocomposites. The sequence ...of structural transformation, phase composition, thermal stability and hardness of mechanically milled IQC-Sn nanocomposite powder were studied through X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning caloriemtery (DSC) and nanoindentation techniques. The XRD result suggests the formation of nano-structured composites. The IQC phase co-existed with monoclinic Al13Fe4 (a = 1.549 nm, b = 0.808 nm, c = 1.248 nm, α = β = 90°, γ = 107.72°; mC102) and B2-type Al (Cu, Fe) (a = 0.29 nm; cP2) phase in IQC-Sn nanocomposite powder subjected to mechanical milling for 40 h. The structural transformation and fraction of IQC, Al13Fe4 and B2–Al (Cu, Fe) phase depends upon the volume fraction of Sn and duration of milling. The crystalline phases formed during milling transformed to a stable IQC phase along with the other crystalline phases during subsequent annealing treatment. The structural transformations occurring during milling have a remarkable effect on indentation hardness, which is in the range of ∼ 4–7 GPa. This suggests that IQC-Sn nanocomposite produced through milling with desirable mechanical properties may be used as potential coating materials for engineering applications.
•Structural transformation of IQC phase to Al13Fe4 and B2-type phases in IQC-Sn nanocomposite.•Order-disorder transformation of B2-type and IQC phase in IQC-Sn nanocomposite.•Crystalline and IQC phase layering enhanced with high volume fraction of Sn.•Evolution of crystalline phases i.e. Al13Fe4 and B2–Al (Cu, Fe) phase during heating of IQC-Sn milled nanocomposite powder.•Hardness of IQC-Sn milled powder upto 40 h varies ∼ 4–7 GPa as a function of Sn fraction.
The present investigation reports the formation and stability of multi-component AB2-type Laves phase in Ti–Zr–Ni (V, Cr, Fe, Mn, Co)ternary to octonary alloys system. To probe the formation and ...stability of AB2-type Laves phase in high-entropy alloys, a series of multi-component alloys have been synthesized via melting under protective Ar atmosphere and subsequent annealing at 525 K for 40 h. Systematic investigation has been carried out to understand phase stability using both thermodynamic and parametric approaches. X-ray diffraction measurement and Rietveld analysis indicate the formation of C14 Laves phase in multi-component alloys. The enthalpy of mixing (ΔHmix), size difference (δ) and valence electron concentrations (VEC) have been found to play stellar role in controlling the formation of multi-component Laves phase in these alloys. The valence electron concentrations and electrons per atom ratio (e/a) dictate the choice of elements for the stabilization of Laves phase in these high-entropy alloys.
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•Evolution of C14 Laves phase in Ti–Zr–Ni (V, Cr, Fe, Mn, Co) multicomponent High-entropy alloy.•Lattice contraction with addition of alloying elements.•The relationship of the thermodynamic and physicochemical properties of alloying elements with Laves phase stability.•Role of VEC and e/a in determination of Laves phase.
Membranes in cells have defined distributions of lipids in each leaflet, controlled by lipid scramblases and flip/floppases. However, for some intracellular membranes such as the endoplasmic ...reticulum (ER) the scramblases have not been identified. Members of the TMEM16 family have either lipid scramblase or chloride channel activity. Although TMEM16K is widely distributed and associated with the neurological disorder autosomal recessive spinocerebellar ataxia type 10 (SCAR10), its location in cells, function and structure are largely uncharacterised. Here we show that TMEM16K is an ER-resident lipid scramblase with a requirement for short chain lipids and calcium for robust activity. Crystal structures of TMEM16K show a scramblase fold, with an open lipid transporting groove. Additional cryo-EM structures reveal extensive conformational changes from the cytoplasmic to the ER side of the membrane, giving a state with a closed lipid permeation pathway. Molecular dynamics simulations showed that the open-groove conformation is necessary for scramblase activity.
With more than 21,000 MW installed capacity of renewable energy sources as of now out of an estimated potential of about 189,000 MW, in the years to come it is really a challenge to integrate the ...same into the smart grids in a country like India. This is basically on account of unevenly distributed renewable resources. With 5 regional grids gradually getting connected, formation of national grid in totality is a reality. Of course with major sources of generation being thermal with availability up to certain distant future, entire thrust has been put in recent years on the development of renewable resources that would be the source of energy to run side by side to the conventional ones. At the same time vast assets created in transmission and distribution will also continue to be gainfully used, may be in conjunction other form of value addition to the same for proper functioning. Under this condition, keeping in mind the eventualities, regulations have been framed and so also the certification process has been made effective to handle the situation particularly on grid connectivity front. Expectations from smart grids by the consumers and suppliers as well of course may lead further refinement to the existing protocols in the process in the years to come as and when harnessing of renewable resources progresses to attain a very high level.
The outstanding properties of the high entropy alloys (HEA) are attributed to various factors like composition, microstructure, phase formation, synthesis route etc. In this regard, the present ...investigation deals with phase evolution, microstructure, thermal stability and microhardness properties of an equiatomic quinary Cr-Mn-Fe-Co-Mo high entropy alloy synthesized by mechanical alloying followed by pressure-less sintering. The structure and phase evolution with milling time was studied by x-ray diffraction technique. After completion of 40h of milling, two simple solid solution phases with BCC structure (a= 3.146 ± 0.002Å and 2.873 ± 0.002Å) along with a minor amount of undissolved α-Mn were identified. Phase formation, chemical composition, thermal stability etc. were also evaluated using electron microscopy and differential thermal analysis (DTA) methods as well as in-situ high temperature x-ray diffraction technique. In the sintered sample, four phases consisting of two BCC solid solution, σ (sigma) and μ (mu) phases are observed to coexist and to be stable up to the melting point. The phase formation was predicted by Thermo-Calc approach and was compared with the experimental observation as well as other calculated results. The sintered samples were tested by instrumented hardness tester for evaluation of mechanical properties and was found to exhibit high hardness (9.3 ± 0.3GPa) and Young’s modulus (~245 ± 6GPa).
•A new equiatomic quinary CrMnFeCoMo HEA has been prepared by mechanical alloying followed by pressure less sintering.•Two BCC solid solution phases along with minor α-Mn is formed after 40h of milling. The sintered alloy consists of a major σ-type phase along with a μ-type phase and two BCC solid solution•The alloy is thermally stable upto 400 °C and beyond that intermetallics start to form.•The sintered pellet possesses excellent hardness value of 9.3GPa
A 30‐day feeding trial was conducted to evaluate dried fish and chicken viscera, and a combination of oil cakes as complete substitutes for fish meal in the diet of catfsh Clarias batrachus (Linn.) ...fingerlings. Triplicate groups of fingerlings with a mean initial body weight of 2.0 g were each fed four isonitrogenous diets at 4% of wet body weight. Performance of the diets was judged on the basis of feed acceptability, body weight gain, feed conversion ratio and protein efficiency ratio. A significant increase (P < 0.05) in body weight gain, protein efficiency ratio and a decreased feed conversion ratio (P < 0.05) was observed in fish fed on fish meal, followed by fish viscera, chicken viscera and only plant protein incorporated diets. Although inferior to fish meal and dried fish viscera, growth and feed utilization responses of fingerlings fed on dried chicken viscera and plant protein diets were similar. The fish accumulated a significantly greater (P < 0.05) amount of fat (18.3%) in the body carcass when fish viscera was incorporated in the diet. The study revealed that satisfactory growth and feed utilization responses could be achieved through replacement of fish meal by dried fish and chicken viscera in the diet of catfish fingerlings.
In this Letter, the authors propose to apply the harmonic regeneration noise reduction (HRNR)-based Wiener filter (W-HRNR) to detect acoustic emission (AE) signal from the noisy environment. HRNR ...technique can regenerate the harmonics to overcome the distortion which occurs with overestimation of conventional Wiener filter and to preserve the essential signal content for accurate detection of AE signal. W-HRNR is implemented in short-time Fourier transform domain. Decision direct method is employed to estimate the spectral gain and signal-to-noise ratio (SNR) of the signal in each frame. Evaluation of the algorithm is carried out using peak-SNR (PSNR) and mean square error (MSE). The performance of the proposed algorithm has been demonstrated using a simulated AE burst signal and AE signals acquired from compression test and drilling test. Results have proven the remarkable performance of W-HRNR over existing conventional Wiener filter for AE with accurate detection by preserving the useful signal information even under high noise conditions at low frequencies. Moreover, W-HRNR also achieved a significant improvement in PSNR and MSE over the conventional filter.
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