Piyush sharma | Thapar University, Patiala (original) (raw)

Papers by Piyush sharma

In the present study, novel mesoporous bioactive glasses (MBGs) (15-x)CuO-xMgO-10P 2 O 5-60SiO 2-... more In the present study, novel mesoporous bioactive glasses (MBGs) (15-x)CuO-xMgO-10P 2 O 5-60SiO 2-10CaO-5ZnO (2.5 x 12.5, varying in steps of 2) are synthesized using the sol-gel technique. The structural phases of the glasses/ glass ceramics were studied by XRD. The pH variation and simulated body fluids (SBF) studies demonstrated the in-vitro bioactivity of all the MBGs. MBGs possess surface area variation between 98.22 and 442.41 cm 2 /g. The pore size of MBGs lies in the range of 5.8–8.8 nm. The cytotoxicity assays were conducted for MG63 human osteosarcoma cell line depicting non-toxic behavior of all MBGs at 7.8125 lg/ml. In addition to this, the effect of the magnesium on the gene expression was also investigated using reverse transcription–polymerase chain reaction (RT-qPCR). The MBGs were loaded with the antibacterial (vancomycin/amoxicillin), anticancerous (doxor-ubicin), and analgesic (Iburofen) drugs. Ibuprofen and amoxi-cillin drugs were almost fully loaded in all the MBGs, whereas doxorubicin and vancomycin drugs illustrated variation in loading with decreasing copper content. V C 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 00A:000–000, 2018.

The mass loss of eucalyptus wood was measured against time and temperature at four different heat... more The mass loss of eucalyptus wood was measured against time and temperature at four different heating rates (5, 10, 15, 20 °C/min), in nitrogen environment , through thermogravimetry analysis technique. These measurements revealed that the decomposition of wood samples occurred in three stages (dehydration stage, active stage and passive stage), and the maximum decomposition peak in DTG curve shifted towards higher temperature range with increase in heating rate. In addition, the decomposition kinetic parameters were determined by adopting two thermal kinetic methods viz. Flynn–Wall–Ozawa and modified Coats and Redfern. Further, from the master curves (generated through different values of g(a) and f(a)) and experimental curve obtained using the Criado method, the kinetic mechanism involved in the pyrolysis of the eucalyptus wood was commented.

Carbon coated nano molybdenum carbide (Mo 2 C) has been synthesized at 800 °C through single step... more Carbon coated nano molybdenum carbide (Mo 2 C) has been synthesized at 800 °C through single step reduction route using molybdenum trioxide (MoO 3) as a precursor, polypropylene (P.P) as a carbon source and magnesium (Mg) as a catalyst in an autoclave. The synthesized samples were characterized by X-ray diffraction (XRD), thermal analysis techniques (TG/DTA/DTG), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Williamson-Hall (W-H) analysis has been done to estimate various parameters like strain, stress and strain energy density. Multi-stage kinetic analysis of the product phase has been studied to establish the nature of the thermal decomposition. Coats-Redfern method applied to determine the mechanism involved in the decomposition of the product phase shows that initial and final stage follow F1 mechanism whereas middle stage follow F3 mechanism. The activation energy (E a) and pre-exponential factor (A) has also been determined. The morphological studies shows that the particles have partially spherical/faceted shape, with carbon coated having wide particle size distribution. The surface chemistry and surface area analysis were studied by X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmet-Teller (BET), respectively. The formation mechanism of carbon coated Mo 2 C nano particles has been predicted based on the XRD, TG/DTA & DTG and microstructural results. The industrial demand of transition metal carbides (TMCs) is increasing due to their remarkable physical and chemical properties. The high melting point, good conductivity, thermal stability, excellent corrosion, wear resistance and catalytic properties similar to noble metals of Mo 2 C find many industrial applications 1–5. The Mo 2 C particles are highly active HER (Hydrogen Evolution Reaction) catalyst and has stability in both acidic and basic mediums 6, 7. Because of these extensive applications of Mo 2 C, synthesis of nanocrystalline Mo 2 C utilizing low cost carbon source by simple route at lower temperatures is eminently desirable. The catalytic activity of Mo 2 C is mostly influenced by surface structure and elemental composition, which are dependent on the synthesis route 8. Traditionally, the micron size Mo 2 C is produced by direct carburization of molybdenum and molybdenum oxide powders at higher temperatures 9. However, for the synthesis of nano Mo 2 C powder different procedures are adopted 10–17. The structure and crystallite size of carbides mainly depends on the synthesis temperature, type and concentration of carbon source 18–20. The morphology of particles depends upon nature of the carbon and reaction time that plays an important role. Chen et al. 21 synthesized Mo 2 C at 600 °C using MoO 3 in an autoclave in presence of Mg and CH 3 COOK as reducing agent and carbon source, respectively. However, the authors did not establish the mechanism of reduction. Moreover, the processing parameters have not been optimized. In this paper, synthesis of Mo 2 C through a simple reduction and carburization of MoO 3 in an autoclave is reported. For the synthesis, polypropylene and Mg are used as carbon source and catalyst, respectively. Polypropylene is a thermoplastic polymer and used for manufacturing variety of plastics. In order to recycle the plastics and to conserve the natural products, the current path is followed 22. Furthermore, the kinetic analysis involved in the thermal decomposition process is crucial to understand the thermal stability of materials for wide range of applications. Numerous researchers have evaluated various kinetic parameters (activation energy, pre-exponential factor and co-relation factor) and proposed the reaction mechanism, by adopting well known thermal kinetic models 23–27. However, so far no kinetic study has been done to determine the kinetic parameters

Eucalyptus wood samples are impregnated with 5 and 15% concentration of ammonium dihydrogen phosp... more Eucalyptus wood samples are impregnated with 5 and 15% concentration of ammonium dihydrogen phosphate (ADP) flame retardant, for three impregnation times (1, 3 and 5 h). These impregnated samples along with un-impregnated eucalyptus wood are analysed using thermal analysis technique, and thermal decomposition parameters are measured. Further, activation energy of these samples, for each stage of decomposition, are determined by employing different kinetic models namely Horowitz and Metzger, Broido, Coats and Redfern and Ozawa-Flynn-Wall. The results based on these models show that the activation energy of impregnated wood samples decreases with increase of ADP concentration and impregnation time. Finally, the wood samples are analysed through scanning electron microscopy to glimpse the surface morphology.

The lithium titanate formation through solid-state reaction between lithium carbonate and

The xCuS-45P 2 S 5-(55 − x)Na 2 S (mol% 2.5 ≤ x ≤ 10) glasses are synthesized through melt-quench... more The xCuS-45P 2 S 5-(55 − x)Na 2 S (mol% 2.5 ≤ x ≤ 10) glasses are synthesized through melt-quench method. Compositional dependent local structure, thermal stability, crystallization kinetics and electrical conductivity are investigated through various techniques. X-ray diffraction showed that a crystalline peak of Cu 1.8 S is observed in all the glass samples. The intensity of Cu 1.8 S peak increases with the addition of CuS in the glass samples. The de-polymerization of phosphate structural units from Q 2 → Q 1 → Q 0 is observed by increasing CuS content, as evidenced from FT-IR and Raman studies. The glass transition temperature (T g) and crystallization temperature (T c) peaks shift towards higher temperature with increased CuS content. This phenomenon indicates that the thermal stability of the glass samples enhanced with increase in CuS content. The crystallization kinetics is investigated using Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods. It is observed that the trend of activation energies remains identical in both crystallization zones, as calculated from both methods. The mechanism involved during the crystallization of glass samples is proposed by evaluating Local Avrami exponent (LAEX). The room temperature electrical conductivities were measured and the maximum value of ac (2.86 × 10 − 4 S cm − 1) and dc (3.85 × 10 − 5 S cm − 1) conductivities were obtained for 10CuS-45P 2 S 5-45Na 2 S glass sample. The dielectric response of the sample was also investigated and the dielectric constant was found maximum for 10CuS-45P 2 S 5-45Na 2 S glass sample.

The lithium titanate formation through solid-state reaction between lithium carbonate and