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Advances in anticancer drug discovery are focusing on the invention of drugs that specifically prompt cell death and pose lesser toxicity to the customary cells. The proposal aims at evaluating the cytotoxic potential of the non-metallic carbon dot (CDs) nanoparticles as a selective anticancer drug against targeted human carcinoma cell lines of liver (HepG2) and breast (MCF-7) in vitro. CDs were synthesized by a chemogenic method from three different natural carbohydrate derivatives glucose (GCD), sucrose (SCD), and fructose (FCD) and were characterized by UV–Visible, Fluorescence, HRTEM, ATR-IR and Raman spectroscopic techniques. Further compared for their anticancer activity against above mentioned cells. The percent cell viability investigations showed a suitability of CDs for cytotoxic studies. The IC50 of the CDs nanoparticles (SCD, GCD, FCD) on HepG2 cells were

This paper reports on a study of the high-temperature tribological performance of self-lubricating nickel-based composite clad. A porous and crack free clad containing matrix, reinforcement, and lubricant phase is developed on titanium 31 alloy using microwave irradiation. The microstructure of both NiCrSiB/WC and NiCrSiB/WC/Ag/BaF2 clad revealed very good metallurgical bonding with the substrate. The average microhardness of NiCrSiB/WC and NiCrSiB/WC/Ag/BaF2 clad is 710.58 HV and 650.25 HV respectively, is comparatively higher than the titanium 31 substrate (320 HV). The addition of Ag and BaF2 solid lubricants in the clad endowing clad to operate at a broad temperature range. Compared with the NiCrSiB/WC clad, solid lubricant encapsulate clad has shown very low friction coefficient and wear rates. The sliding wear characteristics of the clad were investigated by varying load and temperatures. The results revealed that oxide phases (NiO and Cr3O) and lubricant phases (Ag and BaWO4) formed at low and high temperatures are adequate to reduce delamination and material loss.

In the present study, the mesoporous Ti-SBA-15-SO3H catalyst is synthesized by using the sol-gel method. Further, these materials have been characterized by different advanced analytical techniques such as Low angle X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetry/Differential thermal analysis (TG/DTA), N2 adsorption/desorption studies, Fourier transform infrared spectroscopy (FT-IR), UV–Vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), Temperature-programmed desorption of ammonia (NH3-TPD) and Lactic acid esterification catalytic activity studies. The Ti-SBA-15-SO3H catalyst is found to have a surface area of 457 m2/g, a pore volume of 0.12 cm3/g, a pore diameter of 3.16 nm, and a high acid density of 1.72 mmol/g. The optimum reaction conditions for lactic acid esterification with n-butanol are found to be a 1: 4 M ratio, 3 wt-% catalysts, 115 °C temperature, and 120 min reaction time to obtain 72% conversion. Further, the reusability tests reveal that the spent catalyst can be used for five successive runs without the loss of considerable activity. The pseudo-homogeneous model was able to describe the kinetics of this esterification with negligible error. The activation energy and equilibrium rate constant for Ti-SBA-15-SO3H is found to be Ea = 0.063 KJ/mol and K = 5.019 lit/mol min, respectively, to catalyze the esterification of lactic acid with n-butanol. A plausible mechanism for the catalytic activity is proposed.

In this present experimental work, magnesium matrix composites (MMCs) were manufactured by stir casting method. Magnesium is a metal which is more abundant and has very less density but the problems is it has better wear resistance and low hardness. To improve the properties of magnesium, ZrSiO4 ceramic powder are reinforced. The tribological and mechanical properties of composite materials were investigated. The effects of reinforcement on the mechanical properties of the composites were investigated by 0, 4 and 8 wt% of ZrSiO4 ceramic powder with a size of 40–60 µm. The primary aim is to investigate the mechanical and tribological behaviour of AZ91/ZrSiO4 composites. ZrSiO4 powders are added at required proportions to produce magnesium alloy (AZ91) matrix composites. AZ91 along with ZrSiO4 confirms fine mechanical properties. The demand of magnesium matrix composites has increased mainly due to its high specific strength, better damping properties, excellent cast ability and superior machining ability.

In today’s world slurry handling equipments are facing lot of engineering problems which is namely erosion. Slurry erosion plays a very important role in the design and operation of slurry transportation systems. In the work an attempt is made to reduce slurry erosion by cobalt based clad developed through microwave energy. The microwave clads are developed on AISI 420 substrate with a microwave exposure of 07 min. The developed clad shown great improvement in the erosion resistance than substrate. Slurry erosive wear studies were carried out with focus of three important parameters such as speed, impact angle and time of slurry exposure. ANOVA and control factors analysis studies were carried out with 95% of confidence level. Impact angle shown most dominating parameter on wear rate. Mixed mode of erosion was noticed on the target surface.

Introduction and Aim: The Biosynthesis of Gold nanoparticles (Au NPs) is an eco-friendly, cost effective and nontoxic alternative to chemical and physical methods. In the present study synthesis of Au NPs was performed by using a fungi Penicillium sp. isolated from agriculture soil. Materials and Methods: Fungi was isolated from the agricultural field and inoculated into Sabouraud Dextrose broth and incubated at 28º C in a shaker at 180 rpm for 96 to 120 hours. After incubation, the fungal culture was filtered and centrifuged, obtained fungal cell free extracts treated with 1mM gold salt (HAuCl4). The synthesis of Au NPs was confirmed by UV–visible spectroscopy and particles size was measured using Dynamic Light Scattering (DLS). Haemolytic assay of Au NPs was carried out using Chicken RBCs and results measured at 540 nm in UV-visible spectrophotometer. To study catalytic activity, Bromothymol blue (BB) was subjected to reduction by using sodium borohydride (NaBH4, 5.28X10-2 M) in the presence of Au NPs. Then the color change was monitored by visual observation. Results: The synthesis of Au NPs was preliminary observed by a color change from yellow to purple and confirmed by a peak at 560 nm using a UV–visible spectroscopy. The DLS analysis showed that the Au NPs were poly-dispersed and size ranges from 130 to 150 nm. The biosynthesised Au NPs was studied for their biocompatibility and dye degradation properties. Conclusion: The obtained results revealed that biosynthesized Au NPs shows a minimum level of toxicity to chicken erythrocytes and good catalytic activity towards the degradation of hazardous dye bromothymol blue. These nanoparticles could be potentially useful in various applications in medical and environmental fields.

CoMoCrSi-WC + CrC + Ni and CoMoCrSi-WC + 12Co composite coatings are coated on titanium substrate by high velocity oxygen fuel method (HVOF). Prior to spraying, CoMoCrSi feedstock are processed through high energy ball milling (HEBM) in order improve the intermetallic laves phases and to reduce its particle size. The processed feedstock exhibits amorphous nature by improving laves phases and particle size of 60.12 μm. Microwave heating energy is utilized as post heat treatment technique to improve the mechanical and metallurgical properties of as-sprayed coatings. Fused coatings reveals better properties in terms of surface roughness, porosity, microhardness and adhesion strength compared to as-sprayed coatings. Metallurgical bonding is observed in case of fused coatings due to diffusion of substrate elements. Frictional and wear behaviors have been investigated by a pin on disc apparatus at temperatures of 200 °C, 400 °C, and 600 °C under normal loads of 10 N and 20 N. Both wear trace and friction coefficients of the fused coatings are smaller than as-sprayed coatings and substrate at all test temperatures. The wear traces of fused coatings decreased with increasing the surface temperature due to the lubricant effect of cobalt oxides formed on the sliding surface. As a result, cobalt based cermet coatings are highly recommended as a durability improvement coating for the protection of sliding surface, such as high speed spindle.

Stability of 20 mol% Zr doped BaTiO3 (BZT20) and 20 mol% Sr doped LaMnO3 (LSM20) phases in their ceramic composite under the conventional heat treatment is discussed. (1−x)BZT20-xLSM20 x = 0, 0.25, 0.5, 0.75 and 1.0 composites are prepared from mechanical mixing of sol–gel synthesized BZT20 and LSM20 powders. The composite powders were pelletized under 610 MPa hydraulic pressure, sintered at the temperatures of 900 and 1000 °C for 12 h and characterized for the phase structure by X-ray diffractometer. Crystal structure of the pure phases is established from the Rietveld refinement method. Weight fraction of the phases is estimated from the internal standard method. The stoichiometric observation is correlated with the data available in the literature. It is observed that the A-site cations of the two phases start, though weakly, inter-diffusing at the lower temperature of 900 °C. The two phases at the temperature of 1000 °C partially dissolves into each other with the segregation of Zr-Ti-O based oxide as an intermediate phase. The shift in the LSM20 peak by Ba2+ substitution for La3+ and segregation of Zr-Ti-O is stronger in 75:25 and 25:75 compositions respectively due to percolation effect.

Treating post-surgical wound is one of the major challenges in the field of medical Science due to the several disadvantages posed by the antibiotics. The antimicrobial and Wound healing activity of metal based nanoparticles were well known, but the effects of carbon dot nanoparticles (C-Dots) are less explored. In the present study a wet chemical method for the synthesis of C-Dots from sucrose, glucose and fructose was developed and they were characterized by UV-Visible, Fluorescent spectroscopic techniques and the pharmaceutical applications such as antibacterial and the wound healing activities were evaluated. The study revealed that the C-Dots synthesized from Sucrose (SCD) and Glucose (GCD) showed potent antibacterial activity against both positive and negative bacterial strains at 12.5µl/ml (0.1 ± 0.003) and Fructose (FCD) at 50 µl/ml (0.1 ± 0.01) compared to the vehicle Control (0.61 ± 0.06). The wound healing of SCD (367.8 ± 15.2) was observed better than the Control (280.8 ± 10.72) and FCD (326.8 ± 9.41). GCD (166.8 ± 10.83) skin tissues indicated best healing as compared to FCD (135.8 ± 8.29), SCD (157.3 ± 16.97) and Control (135.8 ± 8.29). The results suggest that C-Dots applied topically possess wound healing activity and have potential applications as a bacteriostatic agent.

Different amounts of graphene-wrapped magnesium oxide (G@MgO) powders are uniformly dispersed in poly(vinyl alcohol) (PVA) solution in different experiments to obtain solutions which are coagulated to obtain solid materials, which are then hot pressed at 413 K and 3 t of pressure to finally obtain 1 mm thick freestanding G@MgO/PVA composite sheets in which the constituents, namely, graphene and MgO (in the form of G@MgO), are the nanofillers in PVA matrix. During synthesis of G@MgO powder, MgO nanoparticles are in situ wrapped by the graphene nanosheets as revealed by electron microscopy. Uniformity of G@MgO dispersion in PVA was confirmed by secondary electron micrographs and the consistency in X-ray diffraction and Raman scattering data collected from different locations of the samples. Temperature (303-393 K) dependent complex permittivity of G@MgO/PVA composite sheets (including those prepared by casting) in low frequency (20 Hz to 2 MHz) and high frequency (i.e., X-band, 8.2-12.4 GHz) ranges are measured. In both frequency ranges, G@MgO/PVA composite sheets prepared by coagulation exhibited dielectric properties superior to those of PVA and G@MgO/PVA composite sheets prepared by casting. A strong interfacial polarization is observed in coagulated and as-cast G@MgO/PVA composite sheets. It is noticed from the calculated activation energies that conduction is the dominating mechanism for energy transfer in both composite sheets' cases, while it is predominating in coagulated composite sheets due to the better network formation of the fillers in the coagulated samples than in the cast composite samples. The electromagnetic interference shielding effectiveness (EMI SE) values in the X-band frequency range (i.e., 8.2-12.4 GHz) of the G@MgO/PVA composite sheets prepared by coagulation are more than those prepared by casting for a particular weight fraction of G@MgO. At 393 K, for a particular G@MgO/PVA composite sheet prepared by coagulation, an excellent EMI SE of ∼27.5 dB is measured. It is also experimentally elucidated that the absorption is the dominating mechanism for EMI SE in the prepared composite sheets.

A convenient and efficient metal free, atom economical flexible synthesis of β-carbolines involving a domino Pictet-Spengler reaction and aromatization in oxygen atmosphere in N-methyl-2-pyrollidone (NMP) is described. Variety of aryl, heteroaryl and aliphatic aldehydes were found to be good substrates for this methodology. Several β-carbolines (6a-6t) and β-carboline methyl esters (7a-7e) were synthesized using this methodology.The same reaction carried out in argon atmosphere in the presence of catalytic amount of acid in NMP furnished, tetrahydro-β-carbolines (4a-4g).

The aim of the present study is to improve the sliding wear resistance of pure titanium grade-2 substrate by developing CoMoCrSi (Tribaloy T400) cladding on it by using microwave hybrid heating technique. The developed cladding is characterized by microstructural features, phase analysis, measurement of microhardness by employing a scanning electron microscope (SEM), X-ray diffraction (XRD) and Vickers microhardness. The cladding and substrate are subjected to sliding wear test against alumina counterpart at elevated temperatures under dry conditions using a pin on disc tribometer. The test is performed by varying normal load and temperatures, whereas sliding speed is maintained constant. The developed clad shown partial melting of CoMoCrSi powders and obtained sound metallurgical bonding with the substrate. The high specific energy of microwave diluted the substrate atoms into cladding region which forms Cr3C2, Co3Ti, and TiC, phases confirmed by phase analysis. The cladding obtained better porosity and microhardness are 1.5 ± 0.2% μm and 760 ± 35 Hv respectively. The substrate exhibits low microhardness of 182 ± 25 Hv. The cladding exhibits 6 times of lower volume loss and 70.14% of less wear rate with respect to the substrate. The cladding experienced least coefficient of friction is 0.55 compared with the substrate. The worn surfaces of cladding and substrate are examined. The detailed mechanism of wear is discussed in this paper.

Vanillin and its derivative, (4-((E)-(4-hydroxy-2-methylphenylimino) methyl)-2-methoxyphenol (MMP) were showed clear inhibition of violacein and pyocyanin at sub-MICs indicating a possible quorum quenching effect of both the compounds. MMP was able to inhibit the biofilm formation in Pseudomonas aeruginosa PAO1 at 125 μg/mL (p < 0.05), while vanillin at 250 μg/mL (p < 0.05) indicating that they act against quorum sensing regulated biofilm formation. The inhibition of biofilm was confirmed by visualization through fluorescence microscopy followed by docking analysis of molecules against quorum sensing activator proteins. Caenorhabditis elegans survival assay revealed that vanillin and MMP were able to increase survival of C. elegans from P. aeruginosa PAO1 infection. The study showed that the potent features of the MMP and vanillin in inhibiting the quorum sensing regulated virulence and biofilm, which was proved in C. elegans infection model as well as molecular docking studies.

Reducing processing time and enhancing the performance of a product is the main focus of industries. Aluminum matrix composites (AMCs) find application in various engineering areas due to their low cost and tailorable mechanical properties. Many existing methods are available to fabricate AMCs, but stir casting is the accessible route. The existing stir casting methods employ a conventional heating source that consumes more time and energy. The application of microwaves in material processing has been explored because of its attributes, such as fast and uniform heating leading to a superior product. In the present work, aluminum matrix composite (AMC) was successfully developed using a novel microwave stir casting process. Aluminum alloy 6061 (AA6061) was used as a matrix and silicon carbide (SiC) particles (2 wt.%) as reinforcement. The prepared composite is characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Vicker’s microhardness test. The microstructural study confirms the dispersion of SiC particles in the AA6061 matrix without any voids. The microhardness study reveals the composite had a hardness of 62 Hv, increased by 12% compared with as-received AA6061.

We report the results of an extensive structural, Raman scattering and dielectric investigation of nanocrystalline Lu1- xHoxFeO3 (0 ≤ x ≤ 1) orthoferrite, synthesized by the hydrothermal method. The Raman modes specific to the rotation of FeO6 octahedra assert that 5 at.% Ho solute concentration suffices to stabilize the orthorhombic structure in the LuFeO3 host. We observed two new Raman modes at ≈ 53 and ≈ 69 cm −1 in all the compositions. The Raman mode Ag (3) [Ag (5)] wavenumber increases linearly with the FeO6 octahedra tilt angle φ[010] [θ[101]], indicating that these independent modes are sensitive to orthorhombic distortion. The real (e’), imaginary (e”) parts of the complex dielectric permittivity, measured at room temperature over the ac electric-field frequency range, 20 Hz ≤ f ≤ 2 MHz, unravel two different types of dielectric relaxation in nanocrystalline Lu1-xHoxFeO3.

Biosynthesis of gold nanoparticles (GNPs) is an eco-friendly, cost effective and nontoxic alternative to chemical and physical methods. The microbe which inhabits nearly all surfaces on the earth, an attainment typically attributed to their metabolic adaptability. The organism which resides in gold mines would be having more capability to resist against soluble gold toxicity and produce gold nanoparticles efficiently. In the present study, we report for the synthesis of GNPs by a member of Bacillus subtilis isolated from Hutti gold mine, India. The synthesis of GNPs was observed by a color change from yellow to pink and confirmed by a peak around 545 nm using a UV–visible spectroscopy. The synthesized GNPs were further characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The results show that synthesized GNPs are well dispersed and their size ranges 20–25 nm. The present work is aimed to use green synthesized GNPs as catalyst to degrade Methylene blue (MB) and these GNPs could be used to degrade toxic dyes in the environment.

A simple and efficient procedure was developed for the preparation of a variety of aryl, hetero aryl and alkyl N-sulfinylimines (2b-2u) with excellent yields (85–94%) using tungstophosphoric acid as catalyst. Also, this new synthetic protocol features high conversion, shorter reaction time, a straight forward and simple work up procedure. Catalyst was recycled for 10 times without much loss in activity and also scaled up in gram level with high yield. Hence, it is highly applicable for the industrial scale up process.

AISI-420 stainless steel is widely used to manufacture hydraulic and gas turbine components. The present work is concerned with microstructural studies of cobalt based clad developed through microwave energy in a microwave applicator. A domestic microwave oven was successfully used to develop clads at 2.45 GHz frequency. The developed clads were evaluated using optical metallography, scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction (XRD) to determine the microstructure, phases and elemental composition of developed surface. The microstructure study reveals that the developed clad shows good metallurgical bond between substrate without any interfacial cracks. XRD study confirms the presence of various complex metal carbides and intermetallics like Cr7C3, Cr3C2, M23C6, Cr2Ni3 which are formed during microwave heating. The average microhardness of the developed clad surface is 807 ± 96 HV, which is 132% higher than that of unclad surface (348 ± 7 HV).

Unmodified and sulfate-modified SBA-15-supported Cr2O3 catalysts were prepared by impregnation method. The physico-chemical properties of the supports and catalysts were determined by nitrogen adsorption/desorption, powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), laser-Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy (UV-DRS), inductively coupled plasma optical emission spectroscopy (ICP-OES), transmission electron microscopy (TEM) and temperature-programmed reduction (TPR) techniques. Oxidative dehydrogenation of ethane to ethylene (ODE) with CO2 as oxidant was carried out on these catalysts in a fixed-bed reactor at temperatures in the range of 600–700 °C and at atmospheric pressure. The changes in structural and textural properties because of sulfate modification were identified. Sulfate modification affected the nature of interaction of CrO x species with the SBA-15 support. During the evaluation, it was observed that sulfate modification enhances ethane conversion and ethylene selectivity of the catalyst. Better dispersion of CrO x and the increase in Cr6+/Cr3+ ratio seem to be the reasons for the higher performance of the sulfate-modified catalysts compared to that of the unmodified catalyst.

In the present study, phytochemicals-mediated rapid, stable and eco-friendly synthesis of gold nanoparticles (GNPs) using Pterocarpus santalinus L. (Red Sanders) bark extract is reported. The powerful characteristics of different phytochemicals present in P. santalinus L. bark prompted us to determine their efficacy in the bio-reduction of gold chloride trihydrate to the corresponding GNPs. The biosynthesis of GNPs was investigated at the physiological condition (pH = 7.4). The synthesized GNPs were characterized by UV–visible spectroscopy by measuring the peak in the range of 400–700 nm. The GNPs synthesized at physiological conditions revealed surface plasmon resonance (SPR) at 545 nm. The crystalline nature of GNPs was confirmed by using x-ray diffraction (XRD), and the functional groups adhered on the surface of the GNPs were analyzed by Fourier Transform Infrared spectroscopy (FTIR). Transmission Electron Microscopy (TEM) analysis showed spherical GNPs in the size range of 13–26 nm. The synth...

The strength, hardness, wear and corrosion resistance are the most important mechanical properties of the tribological components. Martensitic stainless steel plays very important role to represent these characteristics. The AISI-420 stainless steel widely used to manufacture the hydraulic and gas turbine components. The present work deals with microstructure and slurry erosive wear studies of cobalt based clad developed through microwave energy at a frequency of 2.45 GHz. The scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis result reveals the presence of cobalt and chromium rich solid solution in the intercellular substances. The Taguchi orthogonal array was used to gauge the factors affecting the wear significantly. The influence of various factors such as speed, particle size and impingement angle on wear behavior was evaluated by Means and ANOVA (analysis of variance). It was observed that the slurry speed significantly influenced the more mass loss on unclad substrate. The wear mechanism of the worn surface was studied through a scanning electronic microscope. It shows the mixed mode of erosion in the form of microcutting, ploughing, and fractures appeared are major wear mechanisms.

In the present work, clads were developed through microwave energy which is as an emerging trend. Martensitic stainless steel (SS-420) is considered as a substrate material to improve its surface properties. In the present work, clad powder such as tungsten carbide and cobalt-based powders were used in the weight ratio of 1:0.12, respectively. The clads were developed using domestic microwave oven at 2.45 GHz frequency and 900 W power through microwave hybrid heating technique. After performing a number of trials, the clads were developed with good metallurgical bond with an exposure time of 30 min. The main objective of clad development is to obtain a good mechanical and tribological properties. Wear studies through pin-on-disc method of the developed clad was performed on the basis of Taguchi method (L9) orthogonal array. The main influencing factors considered are sliding distance, sliding speed and load. It is observed that the sliding distance is most dominating factor than load and sliding speed.

In the present work, microwave cladding was carried out as a processing method for enhancement of surface properties of Chromium-austenitic stainless-steel (SS-321). Cladding of Nickel based alloy powder of approximately 0.2 mm thickness was developed on SS-321 substrate. Microstructural characterization was done on the developed clad cross sections using Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Spectroscope (EDS) and X-Ray Diffraction (XRD) analysis. It revealed good metallurgical bonding of clad layer and substrate by inter diffusion of the constituent elements. From microhardness testing, it was found average microhardness of the clad region as 458 HV and 234 HV in substrate region. Sliding wear test revealed significant wear resistance of clad surfaces compared to unclad surfaces. From cyclic oxidation test, it was observed that the oxide growth in clad samples was less and stable compared to unclad surfaces by thermogravimetric studies. Cladding of substrate surfaces lead to formation of a compound containing chromium, cobalt and silicon due to which formation of transient Ni oxides was inhibited and protective Cr, Co and Si oxides were formed. These oxides avoided diffusion of oxygen into inner layers of clad region and keeping it away from deterioration due to oxidation at 750 °C.

The effect of the La3+ and Gd3+ co-doping on the structure, electric and magnetic properties of BiFeO3 (BFO) ceramics are investigated. For the compositions (x=0 and 0

Ethylene is the most significant product that is being used in different sectors. The demand for ethylene is increasing year by year as it is the preferred raw material in the production of various industrially important products such as HDPE, LDPE, PVC, ethylene glycol, styrene, and ethylene dichloride. Carbon dioxide is a promising oxidant for the dehydrogenation of ethane. The global consumption of ethylene has increased to approx. 160 million ton per year with an annual growth rate of 4%. A significant amount of ethylene is produced by pyrolysis of various hydrocarbon stocks using steam, which is a highly energy-intensive process. Oxidative dehydrogenation of ethane using carbon dioxide is considered as one of the alternative methods for obtaining ethylene with higher yield. This chapter explores the effectiveness of metal oxide catalysts, with a particular interest in achieving higher selectivity to ethylene and better conversion of ethane and carbon dioxide. Various methods of preparation and physicochemical characterization techniques of catalysts were analyzed in detail. Performances of metal oxides and metal oxide-supported Cr2O3 catalysts were evaluated in a fixed-bed quartz reactor at 550–675 °C. Cr2O3 on metal oxide catalysts is suitable for oxidative dehydrogenation of ethane in the presence of CO2. CO2 which acts as a diluent for enhancing the equilibrium conversion of light alkanes and as an agent for the removal of coke formed on the catalyst thus acquires enormous importance.

Nanoparticles of different sizes and shapes can be synthesized by physical and chemical methods. But these methods involve toxic ingredients and hazardous byproducts which may be potentially harmful to either environment or human health. Therefore in the present study, an eco-friendly simple biosynthetic route was used for the synthesis of gold nanoparticles (GNPs) using cell free extracts of Enterobacter aerogenes. The synthesis of GNPs was preliminary observed by color change and confirmed by a peak at 530–560 nm using a UV–visible spectroscopy. The crystalline nature of the GNPs was confirmed by X-ray diffraction. TEM image showed the size of GNPs in the range of 4–6 nm. The functional groups adhered on the surface of the GNPs was analyzed by FTIR. The variation of size, shape and dispersity with the varying gold salt concentration was studied. The synthesized GNPs exhibited good catalytic activity for the reduction of methylene blue by NaBH4.

In heterogeneous catalytic reactions the heat and mass transfer play a vital role in affecting the rate of a reaction. Mass transfer limitations include both the internal and external diffusion of components into and out of the catalyst while heat transfer limitations include whether the reaction taking place is isothermal in nature and to find maximum temperature within the catalyst particle during the course of reaction. In the study of intrinsic rates of reaction both the diffusion mechanism should be negligible prior to the kinetic studies. Oxidative dehydrogenation of ethane over Cr2O3 /Al2O3 using CO2 as oxidant was investigated in a fixed bed reactor. The order of reaction is considered to be One and the internal and external diffusion is studied by Weisz Prater and Mears criteria. Temperature difference with in the catalyst particle computed to check the heat transfer limitations.

Summary In the present investigation microwave processing method was explored for the enhancement of surface properties of austenitic stainless steel (SS-304). The nickel based clads were developed through microwave energy. Taguchi's L9 orthogonal array was successfully adapted to study the slurry erosive wear rate. The obtained result indicated that erosion rate of the developed clad varied between 0.03363 g to 0.03570 g as an increase in slurry parameters like slurry velocity and impingement angle respectively. It is confirmed by the response table for means of DOE that the wear rate of the developed clad was more influenced by the rotational slurry speed and impingement angle; finally the possible mechanisms of the worn surface of the tested samples were observed through SEM.

The Cobalt ferrite (CoFe2O4) powders were synthesized by Co-precipitation method. The as prepared ferrite powders were incorporated into a polyaniline matrix at various volumetric ratios. The as prepared composites of ferrite and polyaniline powders were characterized using X-ray diffraction (XRD), transmission electron microscope (TEM). The particle size of CoFe2O4 is found to be 20 nm. The saturation magnetization (M-s) of all the composites was found to be decreasing with decrease of ferrite content, while coercivity (H-c) remained at the value corresponding to pure cobalt ferrite nanopowders. The complex permittivity (epsilon' and epsilon `') and permeability (mu' and mu `') of composite samples were measured in the range of 1 MHz to 1.1 GHz. The value of epsilon' and mu' found to be increased with ferrite volume concentration.

Mesoporous In2O3 nanocubes were achieved in this present work following a transformation from hierarchical structures of mesoporous In(OH)3 nanocubes synthesized hydrothermally. Appreciable control on the morphology of In(OH)3 nanostructures was attained by optimizing the reactant concentration, ratio of structure directing agent in the reaction medium (water/PEG ratio), the reaction temperature, and time. The synthesized samples were characterized extensively by XRD, TG-DTA, micro-Raman, and UV-DRS. Surface area and pore size distribution were determined from N2 adsorption and desorption isotherms. Morphological evaluations carried out using electron microscopy in scanning (FE-SEM) and transmission (TEM) mode not only provided information on the size and shape of the materials but also revealed the hierarchical assembly consisting of primary and secondary structures. Controlled studies as a function of various reaction parameters and the morphological evolution observed are rationally correlated to propo...

LaxBi1-xFeO3 (LBFO) samples were prepared by sol-gel route using citric acid as chelating agent for x = 0.0 - 0.4. The structure, dielectric and magnetic properties of the LBFO compounds were studied and compared with the corresponding properties of the materials prepared by a conventional solid state reaction. The use of the sol–gel method in preparation lowered the reaction threshold temperature by 200 °C. Effects of the preparation routes and conditions on the phase and microstructures of the materials were investigated in this study using XRD and SEM. The pure BFO without bismuth loss, which cannot be prepared by the solid state reaction, was obtained by the sol–gel method. Sol-gel synthesis could yield a pure phase material at relatively lower temperatures while the solid state method yielded powder with a small amount of the secondary Bi25FeO40 phase. Single phase LBFO prepared by sol-gel method (SG) revealed huge value of dielectric constant than same obtained by the solid state reaction method (SS). Maxwell-Wagner type dielectric dispersion is observed in sol-gel method. Dielectric constant and loss tangent are found to be higher for SG as compared to SS. Huge coercivity (HC) of the order of ~ 15 kOe is observed in both SG and SS samples due to the high anisotropy in these samples. The increase in the magnetization is observed due to the destruction of spin cycloid structure. The enhanced properties made LBFO a promising candidate for the applications in novel memory devices and spintronics. Copyright © 2014 VBRI press.

The present study deals with the synthesis of water based stable colloidal nanoparticles and the study of their heat transfer characteristics. Heat transfer analysis at different loading (0–1.1 wt%) of copper nanoparticles in water was carried out at fixed Reynolds number. Enhancement in the heat transfer coefficient was also studied at different Reynolds numbers by keeping the wt% of copper nanoparticles in the range of 0.7–1.1 wt%. The heat transfer analysis of the copper nanofluid was carried out in a copper tube at constant heat flux. Established correlations were used for the determination of thermal properties in the laminar flow regime. The results showed that the heat transfer coefficient increases with an increase in the concentration of colloidal copper nanoparticles and Reynolds number. For a 1.1 wt% copper nanofluid, a 34% increase in the heat transfer coefficient was observed as compared to the base fluid (pure water).

NiFe 2-x Bi x O 4 (x = 0, 0.1, 0.15, 0.20 and 0.25) nanopowders were synthesized via chemical co-precipitation method. The precursor gels were sintered at 973 K in air for 2 h to obtain the single phase pure nanostructured NiFe 2-x Bi x O 4 spinel. The crystal structure and magnetic properties of the substituted spinel series of NiFe 2-x Bi x O 4 have been investigated by means x-ray diffraction and vibrating sample magnetometer. The values of the saturation magnetization and the coercive field of NiFe 2-x Bi x O 4 nanoparticles were found to decrease with increasing degree of bismuth substitution. The room temperature real and imaginary part of permittivity was measured from 1 MHz to 1.8 GHz. The real part of permittivity was found to increase with increase of bismuth content. The room temperature electron paramagnetic resonance was studied to investigate the magnetic properties at microwave frequency.

The Gd 3+ doped Y 3− x Gd x Fe 5 O 12 ( x =0.0, 0.05, 0.15, and 0.25) nanopowders were prepared using modified sol–gel route. The structural characterizations such as X-ray diffraction, transmission electron microscopy has been carried out. The nanopowders were sintered at 700 °C/3 h. The lattice parameters and density of the samples were increased with an increase of Gd 3+ concentration. The microstructure was analyzed using atomic force microscopy. The room temperature dielectric ( e ′ and e ″) and magnetic ( μ ′ and μ ″) properties were measured in the frequency range 5–50 GHz. with Gd 3+ the dielectric properties were enhanced, but there is a decrease in the magnetic properties. The room temperature magnetization studies were carried out up to 1.5 T. the saturation and remnant magnetization were decreased with an increase of gadolinium concentration. These garnets have low permeability, low losses and a broad distribution of FMR line width which makes them a promising material for microwave devices can be used in the high frequency range i.e. up to 50 GHz.

Background: Acute pancreatitis (AP) is associated with high mortality in its severe form. Conventional laboratory tests used in its diagnosis are fraught with multiple shortcomings. Early institution of intravenous fluid resuscitation can reduce morbidity and mortality. Measurement of urinary trypsinogen-2 using a bedside urine dipstick test may prove useful in early identification of AP.Methods: Patients with symptoms consistent with AP, attending the emergency department, at a tertiary care hospital in southern India, between November 2014 and November 2016, were included in a prospective observational study. The patients underwent routine investigations and additionally were tested with a urinary trypsinogen-2 dipstick test (UTT). The diagnostic performance and the time to reporting of the different investigations were compared with those of UTT. Final diagnosis of AP, made by clinicians, served as the standard.Results: The sensitivities of serum amylase, serum lipase, UTT, ultrasonography (USG) and contrast-enhanced computed tomography (CECT) were 97.1%, 94.1%, 92.7%, 98.3% and 100%, respectively. The respective specificities were 92.4%, 98.5%, 98.5%, 100% and 100%. The average time required to obtain the test report was about half hour from admission in case of UTT, compared to about 3 hours for serum amylase/lipase, 4 hours for USG and 6 hours for CECT.Conclusions: The results indicate that UTT test, due to its high performance indices, simplicity and faster availability of reports, can serve as an ideal screening test for AP and help in early institution of treatment.

The biosynthesis of nanoparticles is a cost effective, eco-friendly and non toxic alternative to physical and chemical methods. In the present study, we report a rapid and eco-friendly method for extracellular biosynthesis of gold nanoparticles (GNPs) using cell free extract of Staphylococcus epidermidis. In this method, the formation of GNPs is rapid as the reaction process completes within few minutes. The synthesis of GNPs was preliminary observed by colour change from pale yellow to pink red and confirmed by peaks at 545–550 nm using a UV–visible spectroscopy. Transmission electron microscopy (TEM) showed formation of well dispersed GNPs in the range of 20–25 nm. Fourier transform-infrared spectroscopy (FT-IR) was used to characterise the functional groups which might have played an important role in reduction and stabilisation of GNPs. The synthesised GNPs showed good catalytic activity for methylene blue degradation. This is the first to report on the rapid and ecofriendly method for the biosynthesis of GNPs by S. epidermidis.

In the present work, microwave joining of stainless steel (SS-316) to mild steel (MS) in bulk form has been successfully carried out using a multimode applicator at 2.45 GHz and 900 W. Principles of hybrid heating were employed using a susceptor medium so as to initiate coupling of microwave with the metals. A nickel based metallic powder was used as a sandwich layer between the bulk pieces. Samples were exposed to microwave radiation in atmospheric conditions. Resulting joints were characterized using field emission scanning electron microscope (FESEM), X-ray diffractometer, microhardness tester and universal testing machine. Microstructure study showed the faying surfaces were well fused and got bonded on either side of the base material. Formation of cementite and metallic carbides were evidenced. The average observed Vickers’ microhardness of core of the joint area was observed to be 133 H v with 0.58% porosity. The ultimate tensile strength of the joint was found to be 346.6 MPa with percentage elongation of 13.58%. Fractography reveals that the joints failed due to both shearing of the brittle carbides and oxides as well as due to plastic flow of the ductile matrix under tensile loading.

Metallurgical joining of high thermal conductivity materials like copper has been technically challenging. This paper illustrates a novel method for joining of bulk metallic materials through microwave heating. Joining of copper in bulk form has been carried out using microwave energy in a multimode applicator at 2.45 GHz and 900 W. Charcoal was used as susceptor material to facilitate microwave hybrid heating (MHH). Copper in coin and plate forms have been successfully joined through microwave heating within 900 s of exposure time. A sandwich layer of copper powder with approximately 0.5 mm thickness was introduced between the two candidate surfaces. Near complete melting of the powder particles in the sandwich layer does take place during the microwave exposure leading to metallurgical bonding of the bulk surfaces. Characterisation of the joints has been carried out through microstructure study, elemental analysis, phase analysis, microhardness survey, porosity measurement and tensile strength testing. X-ray diffraction (XRD) pattern indicates that some copper powder particles got transformed into copper oxides. XRD analysis also reveals that the dominant orientation (3 1 1) in starting copper powder got transformed into a preferential orientation (1 1 1) in the joint. A dense uniform microstructure with good metallurgical bonds between the sandwich layer and the interface was obtained. The hardness of the joint area was observed to be 78 ± 7 Hv, while the porosity in the joint was observed to be 1.92%. Strength character of the copper joints shows approximately 29.21% elongation with an average ultimate tensile strength of 164.4 MPa.

Aluminium based Metal Matrix Composites are the very promising light materials with enhanced mechanical properties. Aluminium Metal Matrix composites (AMC) are identified as one of the very good materials for aerospace and automobile applications because of their lightweight, cost effectiveness and high stiffness. Metal Matrix Composites can be produced by various methods such as liquid infiltration, stir casting, spray deposition and powder metallurgy technique. Microwave processing of metals is a rapid developing technology which will offer significant time saving and can be cost effective. It is a volumetric process and very efficient to obtain high heating rates due to the interaction of microwave with the material in molecular level. The present work is an attempt made to study the fatigue characteristics of microwave processed Al-SiCP metal matrix composite. Sintering of the compacted Aluminium powder with 4% SiC is carried out using microwave energy. The sintered metal matrix composite is subjected to secondary processing of Extrusion. The fatigue characteristics and micro hardness properties are investigated.

Metallic materials are known to reflect microwaves owing to lower skin depth. The present work demonstrates melting of commercially available bulk copper using Microwave Hybrid Heating (MHH) technique. Microwaves generated from a 3.3 kW furnace operating at 2450 MHz are used as a source to heat and melt copper. Complete melting of copper is achieved in 25 minutes. As-received and as-cast copper are characterized using X-Ray Diffraction (XRD) technique to study the phases present. Microstructural study of the as-cast copper under Scanning Electron Microscope (SEM) shows closely packed grain structure with negligible porosity. Hardness of the as-received and as-cast copper are also measured.

The microwave assisted, solvent free, parallel syntheses of title compounds is described in this protocol. Twelve new tetraaryl imidazoles, which are incorporated with the chemotherapeutic pharmacophores, have been synthesized by adopting one pot multicomponent reaction. Attempt has been made to investigate the mechanism behind the formation of tetraaryl imidazoles by product identification method. The synthesized compounds were analyzed by physical and analytical data. The synthesized compounds were evaluated for their antibacterial, antitubercular, and short-term anticancer activity. Compound 13 was found to be the candidate compound to investigate further for its potential anticancer activity. J. Heterocyclic Chem., 46, 278 (2009).

Nickel nanoparticles have been synthesized by a simple wet chemical reduction technique in the presence of a surfactant sodium dodecyl sulfate (SDS) and a capping agent oleic acid. Varying the concentration of the surfactant and the capping agent has been found to critically govern the nature of the nanoparticles prepared. It is observed that at an optimum concentration of SDS and oleic acid, nearly monodisperse Ni nanoparticles are obtained that form highly ordered hexagonally close-packed structures on electron microscopy grids by a simple drop coating procedure. It is also shown that the presence of oleic acid is necessary for the stability of the Ni nanoparticles synthesized. Structural and magnetic characterizations of the nanoparticles are also presented.

Magnetic properties of nanocrystalline Ni samples, with average grain sizes, d = 11(1) nm, 19(1) nm and 30(2) nm, synthesized by pulse electrodeposition, have been studied. We observed that (i) at low temperatures, the effective magneto-crystalline anisotropy constant, K1, increases with the crystallite size so as to reach the bulk value at d = 30 nm, and (ii) the rate of thermal decline of K1(T) slows down as the crystallite size reduces.

Homogeneous single phase GdCrO3 nanoparticles are synthesized by a modified-hydrothermal synthesis. The sample shows a compensation temperature at 128 K, below which the DC magnetization becomes negative and positive at low temperatures due to the competition between the two sublattice magnetization. At Neel temperature (168K), the line width and the intensity show an abrupt transition, revealed from electron paramagnetic resonance spectroscopy.

The purpose of the present study was to develop an optimized gastric floating drug delivery system (GFDDS) containing metoprolol tartrate (MT) as a model drug by the optimization technique. A 2(3) factorial design was employed in formulating the GFDDS with total polymer content-to-drug ratio (X1), polymer-to-polymer ratio (X2), and different viscosity grades of hydroxypropyl methyl cellulose (HPMC) (X3) as independent variables. Four dependent variables were considered: percentage of MT release at 8 hours, T50%, diffusion coefficient, and floating time. The main effect and interaction terms were quantitatively evaluated using a mathematical model. The results indicate that X1 and X2 significantly affected the floating time and release properties, but the effect of different viscosity grades of HPMC (K4M and K10M) was nonsignificant. Regression analysis and numerical optimization were performed to identify the best formulation. Fickian release transport was confirmed as the release mechanism from the optimized formulation. The predicted values agreed well with the experimental values, and the results demonstrate the feasibility of the model in the development of GFDDS.

Magnetic nanoparticles embedded in polymer matrices are good examples of functional nanostructures with excellent potential for applications such as electromagnetic interference shielding, magneto-optical storage, biomedical sensing, flexible electronics, etc. Control over the dispersion of the nanoparticle phase embedded in a polymer matrix is critical and often challenging. To achieve excellent dispersion, competition between polymer–polymer and polymer–particle interactions have to be balanced to avoid clustering of particles in polymer nanocomposites. We report the first deposition of magnetic nanocomposite poly(methyl methacrylate)/polypyrrole bilayers from solution using spin-coating. Fe3O4 nanoparticles have been synthesized using a chemical co-precipitation route. Using a combination of dissolving the polymer and mixing fatty acid surfactant coated Fe3O4 nanoparticles, we have demonstrated the formation of nanocomposites with uniform nanoparticle dispersion. Cross-sectional scanning electron microscopy, transmission electron microscopy, and magnetic measurements confirm the excellent dispersion and superparamagnetic response. Low-frequency impedance measurements on these bilayers are also presented and analyzed.

High quality multilayers of barium ferrite (BaM) and barium strontium titanate (BSTO) were grown in optimized conditions on thermally oxidized Si(1 0 0) and Al 2 O 3 substrates using magnetron sputtering. As-grown films were amorphous and different annealing procedures were explored to stabilize crystalline phases. BSTO and BaM phases were identified using X-ray diffraction and cross-sectional scanning electron micrographs showed sharp interfaces between BSTO and BaM layers. Magnetic hysteresis loops obtained at various temperatures and field orientations showed a large coercivity (∼2500 Oe) consistent with the hard magnetic hexaferrite component. Hysteresis loops also revealed the distinct influence of magnetocrystalline and shape anisotropies at different temperature ranges.

Microwave processing of metals is an emerging area. Melting of bulk metallic materials through microwave irradiation is still immature. In view of this, the present paper discusses the melting of bulk Al 1050 metallic material through microwave irradiation. The melting process is carried out successfully in a domestic microwave oven with 900 W power at 2450 MHz frequency. Metallurgical and mechanical characterization of the processed and as-received material is carried out. Aluminium phase is found to be dominant in processed material when tested through x-ray diffraction (XRD). Microstructure study of as-cast metal through scanning electron microscopy (SEM) reveals the formation of uniform hexagonal grain structure free from pores and cavities. The average tensile strength of the cast material is found to be around 21% higher, when compared to as-received material. Vickers' microhardness of the as-cast metal is measured and is 10% higher than that of the as-received metal. Radiography on as-cast metal shows no significant defects. Al 1050 material melted through microwave irradiation has exhibited superior properties than the as-received Al 1050.

The longitudinal components of the `zero-field-cooled' and `field-cooled' magnetization of amorphous ( TM= Co, Ni) and re-entrant ferromagnetic alloys have been measured in the static mode and at different thermal cycling rates varying from to in constant magnetic fields (H) ranging between 1.5 Oe and 15 kOe. The difference, , is taken to be the direct measure of irreversibility in magnetization. The onset of weak irreversibility and a crossover from weak to strong irreversibility are observed at the temperatures and , respectively, for fields ; depends on x and y. and follow the relations and , where ( stands for or ), which have the same form as those predicted by the modified versions of the Gabay-Toulouse (GT) and de Almeida-Thouless (AT) mean-field (MF) theories that include non-vanishing spontaneous magnetization, but the observed values of the coefficients and are several orders of magnitude larger than the MF estimates. is relatively insensitive while is extremely sensitive to thermal cycling rates (TCR) if they exceed a threshold value. The physical implications of extremely large magnitudes of and , and of the observed TCR-induced shifts in the GT and AT irreversibility lines in the H-T plane, have been brought out clearly while discussing these results in terms of the existing theoretical models.