29 research outputs found

    Mechanochemical synthesis of a new triptycene-based imine-linked covalent organic polymer for degradation of organic dye

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    In the present work, a novel triptycene-based imine-linked covalent organic polymer (TP-COP) was designed and synthesized via room-temperature, solvent-free mechanochemical grinding. The as-synthesized TP-COP material was fully characterized by Fourier transform infrared spectroscopy, solid-state NMR, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller method, thermogravimetric analysis, diffuse reflectance spectroscopy (DRS), and electron paramagnetic resonance (EPR). The HRTEM image of TP-COP clearly indicates the presence of graphene-like layered morphology (exfoliated layers). The DRS study reveals that TP-COP exhibited a low optical band gap value of 2.49 eV, implying its semiconducting nature. Further, the EPR study confirmed the semiconducting behavior of TP-COP through the generation of free radicals. These findings suggest that TP-COP could be used as an efficient photocatayst for the degradation of organic dye (RhB) under solar irradiation. Moreover, TP-COP showed excellent reusability in degrading dye (RhB) without obvious performance decay

    Mechanochemical synthesis of a new triptycene-based imine-linked covalent organic polymer for degradation of organic dye

    Get PDF
    In the present work, a novel triptycene-based imine-linked covalent organic polymer (TP-COP) was designed and synthesized via room-temperature, solvent-free mechanochemical grinding. The as-synthesized TP-COP material was fully characterized by Fourier transform infrared spectroscopy, solid-state NMR, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller method, thermogravimetric analysis, diffuse reflectance spectroscopy (DRS), and electron paramagnetic resonance (EPR). The HRTEM image of TP-COP clearly indicates the presence of graphene-like layered morphology (exfoliated layers). The DRS study reveals that TP-COP exhibited a low optical band gap value of 2.49 eV, implying its semiconducting nature. Further, the EPR study confirmed the semiconducting behavior of TP-COP through the generation of free radicals. These findings suggest that TP-COP could be used as an efficient photocatayst for the degradation of organic dye (RhB) under solar irradiation. Moreover, TP-COP showed excellent reusability in degrading dye (RhB) without obvious performance decay

    Evaluation and comparison of the constitutive expression levels of Toll-like receptors 2, 3 and 7 in the peripheral blood mononuclear cells of Tharparkar and crossbred cattle

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    Aim: This study was undertaken to assess the differential expression levels of toll-like receptors (TLRs) 2, 3 and 7 in peripheral blood mononuclear cells (PBMCs) isolated from Tharparkar and Crossbred cattle belonging to different regions of India. Materials and Methods: PBMCs were isolated from blood samples of Tharparkar cattle from Indian Veterinary Research Institute (IVRI) farm (n=30); Suratgarh farm (n=61); Jaipur farm (n=8) and cross breed cattle from Jaipur (n=47). RNA was isolated from PBMCs and cDNA was synthesized using random hexamers. The expression profiles of TLR 2, 3 and 7 were estimated by real-time PCR and normalized to the expression of β-actin. Results: PBMCs of Tharparkar cattle from Suratgarh, exhibited a significantly higher (p<0.05) constitutive expression levels of TLR2, TLR3 and TLR7 genes as compared to Tharparkar cattle from IVRI or Jaipur as well as the crossbred cattle from Jaipur. PBMCs of crossbred cattle from Jaipur showed higher expression profiles of all the TLRs than Tharparkar cattle from Jaipur and IVRI. Conclusion: Our study indicates, expression levels of TLR2, TLR3 and TLR7 are significantly higher for Tharparkar cattle from Suratgarh than the cattle from Jaipur and IVRI and crossbred cattle from Jaipur. However, crossbred cattle from Jaipur showed higher basal expression levels of all the three TLRs than Tharparkar cattle from Jaipur and IVRI. Results also indicate that PBMCs of Tharparkar cattle show a regional variation in the expression pattern of TLRs

    Microwave absorption property of hydrothermal synthesized RGO/PbFe12O19 nanocomposite

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    In this work, we have studied the microwave absorption properties of nanocomposite of Hexagonal shaped lead hexaferrite (PFO) with reduced graphene oxide (RGO). The hard magnetic lead hexaferrite powder is synthesized using solution combustion method and characterized using powder XRD . Nanocomposite of PFO –RGO is prepared using hydrothermal method .The as prepared nanocomposite is characterized using powder XRD and FESEM. The microwave absorption study of PFO-RGO composite is studied in 2-18 GHz. The simulated RL loss plot suggests that the PFO –RGO composite can achieve a minimum RL of -45 dB at 12 GHz. Therefore, this composite system can be used as promising microwave shield materia

    Steady-shear response of magnetorheological fluid containing coral-shaped yttrium-iron-garnet particles

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    The steady-state magneto-mechanical response of a magnetorheological fluid (MRF), prepared by dispersing 40 wt % of magnetically soft, light-weight coral-network-shaped yttrium iron garnet (YIG; Y3Fe5O12) powder in silicone oil (140 cSt) is studied as a function of shear rate, under different applied magnetic fields (B). The results show that the yield strength (tau(Y)) and viscosity (eta) of the MRF increase with B, and are strongly influenced by the physical parameters of the particles such as morphology and saturation magnetization. The low density of the YIG-particles, leading to higher volume fraction for equal mass loading, results in a higher viscosity in the absence of a magnetic field, in comparison to that of conventional metallic Fe-particle-based MRFs. Due to this, there is a relatively smaller increase in tau(Y) and eta when the magnetic field is switched on. The YIG-particles-based MRF has the advantages of high chemical stability, thermo-oxidative resistance and low-cost

    Effect of Sr-doping on sinterability, morphology, structure, photocatalytic activity and AC conductivity of ZnO ceramics

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    The change in morphology, structure, catalytic activity and ac electrical conductivity of the Sr-doped ZnO (Zn1-xSrxO, x = 0, 0.01, 0.02 and 0.03) ceramic powders was investigated after sintering. The sintering of the Sr-doped samples results in faster growth in particle-size and the shape becomes spherical by dissolution of the sharp edges in order to reduce the strain produced by Sr-doping and to reduce the surface energy. The growth in particle-size reduces the photocatalytic activity. Sr-doping reduces the band gap of ZnO by a small value (similar to 0.1 eV). The ac conductivity values decrease with increase in Sr-concentration, but increase with temperature and frequency. This behavior is due to the conduction by small polarons created by Sr-doping. Our results may facilitate a way for the easy fabrication of monolithic ZnO based devices with improved dielectric and semiconducting properties of ZnO ceramics by doping a small amount of Sr
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