Gargi Dinda; Dipankar Halder; Atanu Mitra
Abstract
We report the successful synthesis of copper nanoparticle (CuNP)-starch composite employing low cost green protocol without inert gas protection. UV-Vis spectroscopy, X-Ray diffraction (XRD) and Transmission electron microscopy (TEM) were used to characterize the CuNP-starch composite. Mono-disperse ...
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We report the successful synthesis of copper nanoparticle (CuNP)-starch composite employing low cost green protocol without inert gas protection. UV-Vis spectroscopy, X-Ray diffraction (XRD) and Transmission electron microscopy (TEM) were used to characterize the CuNP-starch composite. Mono-disperse almost spherical CuNP having average diameter 4.02 ± 0.076 nm was obtained. The catalytic activity of the as-synthesized CuNP-starch composite during reduction of pollutants, like, 4-nitrophenol (4-NP) and dyes, Eosine Blue (EB), Eriochrome Black T (EBT) and Brilliant Cresyl Blue (BCB by NaBH4 has been investigated. High catalytic efficiency of the composite was demonstrated by rapid decrease of the intensity of the UV-Vis absorption peaks at respective λmax of the pollutants with time when reaction mixture contained NaBH4 and small quantity of CuNP-starch composite. The rate constant of each processes was calculated by considering that the reactions follow pseudo-first-order kinetics with respect to substrate. The obtained rate constants for 4-NP, EB, EBT and BCB are 0.021S-1, 0.011S-1, 0.036S-1 and 0.032S-1 respectively. The other application, antibacterial activity was tested against Gm positive and Gm negative bacteria. Plate count and minimum inhibitory concentration (MIC) studies show higher susceptibility of Gm positive bacteria towards CuNP-starch composite. The as-synthesized CuNP-starch composite may find potential application in the field of environmental remedies and antibacterial formulations. Copyright©2018 VBRI Press.
P.P. Pradyumnan; Anju Paulson; Muhammed Sabeer N.A
Abstract
Due to the environmental crisis of energy, the depletion and increasing price of fossil fuel resources, current research focuses on sustainable and renewable energy sources for power generation. Meanwhile, electricity remains the most convenient form of energy in the near future, the conversion of heat ...
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Due to the environmental crisis of energy, the depletion and increasing price of fossil fuel resources, current research focuses on sustainable and renewable energy sources for power generation. Meanwhile, electricity remains the most convenient form of energy in the near future, the conversion of heat into electricity acquires wide acceptance. Thermoelectric generation can be considered as an amble method to scavenge the heat energy for the generation of electricity. In this work we investigate the structural, chemical and thermoelectric property of SnO2 based samples with varying concentration of cobalt ion. The thermoelectric properties were measured in a temperature 100-700 0C and found that cobalt doped samples posses a remarkable effect on transport properties compared to pristine SnO2. Negative thermopower ensured that electrons are the majority charge carriers. Seebeck coefficient for 5 wt % of cobalt doping was found to be -364 µV/K, so that it can be considered as a potential candidate for thermoelectric application. The figure of merit (ZT) of the material gets enhanced on cobalt doping and found to increase with increment in temperature so that it can be used for high temperature thermoelectric application. Copyright © 2018 VBRI Press.
Indu B. Vashistha; Mahesh C. Sharma; S.K. Sharma
Abstract
In this present study Cu2ZnSnS4 (CZTS) thin films were grown by Chemical Bath Deposition (CBD) method at optimized parameters. These as grown CZTS films were annealed at 3000C for different time 1 hr, 2 hr, 3 hr. These films were characterized by scanning electron microscope (SEM), UV-VIS Spectrophotometer, ...
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In this present study Cu2ZnSnS4 (CZTS) thin films were grown by Chemical Bath Deposition (CBD) method at optimized parameters. These as grown CZTS films were annealed at 3000C for different time 1 hr, 2 hr, 3 hr. These films were characterized by scanning electron microscope (SEM), UV-VIS Spectrophotometer, I-V measurement for study of surface morphology, optical and electrical properties respectively. The SEM analysis revealed that surface modification takes place as the annealing time increases. The optical study shows high absorption in visible region and as annealing time increase red shift in energy band gap occurred. The current-voltage characteristics of the specimen indicated that conductivity of film increases with increased annealing time. Thus, annealing time has prominent impact on surface modification which changes optoelectronic properties of CZTS thin film and results shows that film annealed at 3000C for 3 hr gives high absorption and better conductivity for CZTS thin films. Copyright © 2018 VBRI Press.
Chandrani Sarkar; Subhadra Garai
Abstract
We report a novel biomimetic three-dimensional carbon fiber reinforced polymer hydroxyapatite nanocomposite having mechanical compressive strength (~116 MPa) and elastic modulus (~1.9 GPa) for load bearing orthopedic application. The synthetic route is very simple cost effective biomimetic process. It ...
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We report a novel biomimetic three-dimensional carbon fiber reinforced polymer hydroxyapatite nanocomposite having mechanical compressive strength (~116 MPa) and elastic modulus (~1.9 GPa) for load bearing orthopedic application. The synthetic route is very simple cost effective biomimetic process. It does not require any binder/porogen for the synthesis of mechanically strong porous nanocomposite. Physicochemical properties of synthesized nanocomposite are systematically characterized by XRD, FT-IR, SEM and Universal Testing Machine. It revealed that only small fraction of carbon fiber increased the compressive strength (~116 MPa) and elastic modulus (~1.9 GPa) by 11-12 folds from unreinforced polymer hydroxyapatite nanocomposite (compressive strength~ 12MPa, Elastic modulus~ 0.33 GPa). Copyright © 2018 VBRI Press.
Archana Sharma; Anu .; Mushahid Husain; Anurag Srivastava; Mohd. Shahid Khan
Abstract
Surface metal adsorption on 2D structures is demonstrated to be an effective tool for improving hydrogen storage capacity. In the current work, the behavior of Ca atom adsorption on monolayer MoS2 is studied and subsequently its hydrogen storage capacity is investigated computationally using van der ...
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Surface metal adsorption on 2D structures is demonstrated to be an effective tool for improving hydrogen storage capacity. In the current work, the behavior of Ca atom adsorption on monolayer MoS2 is studied and subsequently its hydrogen storage capacity is investigated computationally using van der Waals (vdW) revised Density Functional Theory. It is found that the Ca binds strongly with the MoS2 monolayer without being clustered, leading to high hydrogen storage capacity. It is further shown that five hydrogen molecules to each Ca atom can be adsorbed with the average adsorption energy of 0.23eV per hydrogen molecule, indicating it to be a good choice for reversible adsorption/desorption of H2 molecules at ambient conditions. It is revealed that hybridizations between s orbitals of H2 and p orbitals of S are also responsible for adsorption mechanism, along with coulomb interactions. It is demonstrated that a steady and uniform high Ca coverage can be achieved without clustering and with enhanced binding energy which can be used as high hydrogen capacity storage system. Copyright © 2018 VBRI Press.
Rajani Bharati; S. Suresh
Abstract
The aim of this research work is Synthesis of ZnO/SiO2 with Palash leaves extract nanocatalyst by green synthesis route. Palash leaves extract contain a broad variability of bio-molecules which act as capping and reducing agents and increases the rate of reduction and stabilization of nanoparticles. ...
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The aim of this research work is Synthesis of ZnO/SiO2 with Palash leaves extract nanocatalyst by green synthesis route. Palash leaves extract contain a broad variability of bio-molecules which act as capping and reducing agents and increases the rate of reduction and stabilization of nanoparticles. Nanocatalyst synthesized by this method are eco-friendly and cheap. No work has been found on Butea monosperma (Palash) leaves extract with ZnO nanoparticles. This research work synthesis of ZnO/SiO2 with palash leaves extracts nanocatalysts has been made by using green synthesis route. This synthesized nanocatalyst was used for removal of COD (mg/l) and polycyclic aromatic hydrocarbons as pollutants from petrochemical industrial wastewater. The synthesized nanocatalyst of ZnO/SiO2 with palash leaves extract was characterized using BET surface area, FEG-SEM, EDAX, XRD, and FTIR. Results show that we have synthesized ZnO/SiO2 nanocatalyst with BET surface area 160.23 m2/g and SEM micrograph shows the spot of nano range particles. From SEM test it has been found that we synthesized ZnO/SiO2 nanoparticles in the range of 3 to 35 nm and average particle diameter is 15.8nm. XRD and EDAX result show that we have found nanoparticles of SiO2 and ZnO. FTIR results show that Zn-O, Si-O-Si stretching have been found at 1004.95, 861.24 cm-1 for ZnO and 1270.17 cm-1 for SiO2 respectively. Results shows that optimum percent removal of COD (mg/l) and acenaphthene (polycyclic aromatic hydrocarbon) as pollutant are 70 % and 79% respectably at 0.5g/500ml catalyst loading, at 30oC temperature for 4h reaction time. In Future this catalyst can be used to remove other PAH and phenolic compounds from petrochemical wastewater under visible light also and other industrial wastewater can also treat by this catalyst effectively. Copyright © 2018 VBRI Press.
M.K. Debanath; R.K. Saha; S.M. Borah; E. Saikia; K.K. Saikia
Abstract
In our present investigation, we have synthesized starch-capped Cu doped ZnO (ZnO:Cu) nanoparticles (NPs) by simple wet chemical method and studied their structural, optical and antibacterial effects on/against Gram-positive and Gram-negative bacteria. Chemically synthesized nanoparticle have been characterized ...
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In our present investigation, we have synthesized starch-capped Cu doped ZnO (ZnO:Cu) nanoparticles (NPs) by simple wet chemical method and studied their structural, optical and antibacterial effects on/against Gram-positive and Gram-negative bacteria. Chemically synthesized nanoparticle have been characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive analysis of X-rays (EDAX), high resolution transmission electron microscopy (HRTEM), UV-vis absorption spectroscopy and photoluminescence (PL) spectroscopy for their structural and optical properties. Antibacterial properties have been studied by Staphylococcus aureus (S. aureus, Gram-positive) and Escherichia coli (E. coli, Gram-negative) bacteria. XRD study showed hexagonal wurtzite crystal structure of the prepared ZnO:Cu and nanoformation of the as-synthesized NPs. Nanoparticle formation have been finally confirmed by HRTEM analysis. Antibacterial studies showed excellent resistance of ZnO:Cu to S. aureus and E. coli respectively. Copyright © 2018 VBRI Press.
Santosh A. Mani; Sameer U. Hadkar; Jyoti R. Amare; Madhavi S. Pradhan; Hind Al-Johani; Pradip B. Sarawade
Abstract
In the present study, effect of CNT on optical and thermal properties of mixed thermotropic liquid crystal mixture was studied by various techniques to understand their physical behavior. Some new mesophases have investigated by optical methods viz. Polarizing Optical Microscopy (POM) and Fabry–Perot ...
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In the present study, effect of CNT on optical and thermal properties of mixed thermotropic liquid crystal mixture was studied by various techniques to understand their physical behavior. Some new mesophases have investigated by optical methods viz. Polarizing Optical Microscopy (POM) and Fabry–Perot Scattering Studies (FPSS). It has been observed that these new phase transition occur along with the known phase transition temperatures. These new phase transitions corresponding to new mesophases were also confirmed by thermal study using Differential Thermal Analysis (DTA). The CNT doped thermotropic liquid mixtures can be used in various display application such as LCD monitor with color variation to enhance performance. Copyright © 2018 VBRI Press.
Agnieszka Ślosarczyk; Paulina Jakubowska
Abstract
In presented article the research on sol-gel synthesis of silica aerogel from cheaper precursor water glass with ambient pressure drying was shown. In addition to strengthen the silica aerogel frame the as-received and oxidized carbon microfibers from coal-tar pitch were used. The presence of carbon ...
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In presented article the research on sol-gel synthesis of silica aerogel from cheaper precursor water glass with ambient pressure drying was shown. In addition to strengthen the silica aerogel frame the as-received and oxidized carbon microfibers from coal-tar pitch were used. The presence of carbon microfibers in silica aerogel does not influence the structural parameters, on the contrary, the carbon microfibers diminish the density and contraction during drying of silica aerogel nanocomposite. Modification of the silica aerogels in a mixture of TMCS/n-hexane in 70°C with concurrent modification of carbon microfibers results in obtaining a durable nanocomposite, up to the temperature of 600°C, characterized by high level of hydrophobicity, which is proved by tests on contact angle. Moreover, the analysis with EDS probe proved, in case of the nanocomposites with carbon microfiber, a lack of sodium, being a remnant of the silica gel synthesis from water glass, which implies a higher level of substrate reaction during the sol-gel synthesis, and results in obtaining better parameters of the silica aerogel. Copyright © 2018 VBRI Press.
Dasharath S M; Suhrit Mula
Abstract
The microstructural evolution and mechanical properties of cast brass (Cu-10% Zn) subjected to cumulative strains of 3.0, 5.4 and 7.2 through multiaxial forging (MAF) at cryogenic temperature (77 K) were investigated. The mechanical properties of the homogenized and MAF treated alloy were measured through ...
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The microstructural evolution and mechanical properties of cast brass (Cu-10% Zn) subjected to cumulative strains of 3.0, 5.4 and 7.2 through multiaxial forging (MAF) at cryogenic temperature (77 K) were investigated. The mechanical properties of the homogenized and MAF treated alloy were measured through Vickers hardness testing. The brass deformed up to a cumulative strain of 7.2 showed improvement in the hardness of 2.3 GPa as compared with the as-homogenized annealed (0.55 GPa) alloy. The microstructural evolutions of cryoforged samples were characterized by optical microscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-Ray diffraction (XRD). Thereby, it helps to increase twining activity for further deformation. TEM and AFM investigations confirmed that the formation of subgrains as well as nanotwins is responsible for the improvement of the mechanical properties. Copyright © 2018 VBRI Press.
Rachna .; Baljeet S. Saharan .; Mahender S. Yadav .; Nisha Sharma .
Abstract
A simple and efficient synthesis of silver nanoparticles (AgNPs) is reported here using red Dianthus caryophyllus flower, acting both as reducing and capping agent. The resultant silver colloids were characterized using UV-visible spectrophotometer, X-ray Diffractometer (XRD) and Transmission electron ...
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A simple and efficient synthesis of silver nanoparticles (AgNPs) is reported here using red Dianthus caryophyllus flower, acting both as reducing and capping agent. The resultant silver colloids were characterized using UV-visible spectrophotometer, X-ray Diffractometer (XRD) and Transmission electron microscope (TEM). The surface absorption plasmon response and kinematics of reduction of silver ions were observed by UV-visible spectroscopy. The crystalline fcc structure of AgNPs was confirmed by its XRD pattern. Their morphological study was done with TEM, showing spherically shaped AgNPs in the range 10-20 nm. The antibacterial action was also studied using Agar well diffusion method against pathogenic bacteria cultures (Staphylococcus aureus, Bacillus cereus and Escherichia coli). AgNPs showed better antimicrobial activity against S. aureus culture. Copyright © 2018 VBRI Press.
