Pragati Jamdagni; Poonam Khatri; J. S. Rana
Abstract
The current study reports biogenic synthesis of silver nanoparticles from Elettaria cardamomum. Elettaria leaf extract was used as reducing and capping agent for nanoparticle synthesis from parent solution of silver nitrate. Nanoparticle suspension was characterized mainly using UV-Visible spectroscopy. ...
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The current study reports biogenic synthesis of silver nanoparticles from Elettaria cardamomum. Elettaria leaf extract was used as reducing and capping agent for nanoparticle synthesis from parent solution of silver nitrate. Nanoparticle suspension was characterized mainly using UV-Visible spectroscopy. Synthesis parameters namely, time, metal ion concentration, leaf extract quantity, reaction temperature and pH are well known to affect the final product of synthesis and hence, were varied to assess optimum conditions for synthesis. Nanoparticles synthesized at optimum conditions were washed and characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Nanoparticles obtained were in the size range of 5-80 nm (TEM), with an average particle size of 29.96 nm as calculated using Debye-Scherrer formula and average hydrodynamic diameter of 32.12 nm (DLS). FTIR implicates plausible role of protein part of leaf extract in nanoparticle synthesis and DLS confirms monodisperse nature of the suspension. Nanoparticle suspension was found to be stable after four months of storage at room temperature without the addition of any stabilizing agents. Silver nanoparticles exhibited excellent antifungal activity against various fungal phytopathogens with minimum inhibitory concentration as low as 8 µg/mL for Aspergillus niger, making them potential antifungal agents in the field of agriculture. Copyright © 2018 VBRI Press.
Peteris Lesnicenoks; Liga Grinberga; Laimonis Jekabsons; Andris Antuzevičš; Astrida Berzina; Maris Knite; Gatis Taurins; Šarūnas Varnagiris; Janis Kleperis
Abstract
Hydrogen storage is one of the main problems, to catalyse wide hydrogen use in transportation, technology and energetics. Composites involving nanostructured carbon species could be the solution for hydrogen storage problem because of their promising surface/volume relation. Not only catalysis and gas ...
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Hydrogen storage is one of the main problems, to catalyse wide hydrogen use in transportation, technology and energetics. Composites involving nanostructured carbon species could be the solution for hydrogen storage problem because of their promising surface/volume relation. Not only catalysis and gas sensing on graphene basis should be considered, but also metal decorated graphene structures for use in hydrogen storage should be an active field for research and development. Heat conductivity and large surface area of graphene-like materials can endorse research for hydrogen storage in low pressures and close to room temperature (RT) conditions - increasing possibility for RT-range devices in hydrogen energetics. For increased hydrogen storage investigations, we propose metal intercalated graphene structures, acquired during synthesis of graphene sheets. Intercalation, or decoration of graphene surfaces and edges have shown possibility to stabilize defects in graphene sheets. Graphene defects have shown to be sensitive against hydrogen gas and might as well prove themselves stable enough to achieve low pressure hydrogen storage. A simple method is proposed for synthesis of graphene sheet stacks (GSS). There is lack of research for synthesis of carbon nanomaterials from industrial graphite waste. Our research for stabilization of electrolyte solution and increased production amounts for hydrogen accepting samples continues. Copyright © 2018 VBRI Press.
Sudhanshu Kanaujia; Sanjay K. Singh; Bharat Singh
Abstract
A comparative study was done for removal of fluoride by Al (III) modified Clinoptilolite (AC) and Carbonised Punica Granatum Carbon (CPGC) through batch techniques. The fluoride removal performance of both adsorbents AC and CPGC was evaluated as a function of the initial concentration, adsorbent ...
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A comparative study was done for removal of fluoride by Al (III) modified Clinoptilolite (AC) and Carbonised Punica Granatum Carbon (CPGC) through batch techniques. The fluoride removal performance of both adsorbents AC and CPGC was evaluated as a function of the initial concentration, adsorbent dose, contact time and pH. The equilibrium was attained at 90 and 75 minutes for AC and CPGC adsorbents, but percentage of removal was 76 and 65 for AC and CPGC respectively. The maximum adsorption of fluoride was found at pH 6.95 and 5.92 for AC and CPGC adsorbent respectively. The system followed the Freundlich isotherm model for both AC and CPGC with adsorption capacity 0.24 mg/g and 0.4 mg/g respectively. Copyright © 2018 VBRI Press.
Rajesh Kalia; J. K. Sharma; Sapna Kalia
Abstract
The dielectric constant (ε') and dielectric loss (ε״) of pristine and C5+ (70 MeV) ion irradiated samples of the PEEK have been investigated with the variation of temperature at different frequencies (100 Hz, 1 kHz, 10 kHz and 100 kHz). The maxima are obtained around 170 oC in dielectric ...
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The dielectric constant (ε') and dielectric loss (ε״) of pristine and C5+ (70 MeV) ion irradiated samples of the PEEK have been investigated with the variation of temperature at different frequencies (100 Hz, 1 kHz, 10 kHz and 100 kHz). The maxima are obtained around 170 oC in dielectric constant (ε') vs. temperature (T) curve. This relaxation is linked with the movement of ketone (>C=0) dipoles linked to the main chain. The irradiation of polymers increases the orientational polarization due to increase in number of dipoles with fluence. The increase in dielectric constant (ε') and dielectric loss (ε'') is attributed to chain scissioning at higher fluence which results in an increase of free radicals and unsaturations. Copyright © 2018 VBRI Press.
Ramoshweu S. Lebelo
Abstract
In this article, an investigation into the impact of radiative heat loss in a stockpile of combustible material is considered. The heat loss is due to exothermic chemical reaction when carbon containing material of the stockpile reacts automatically with oxygen trapped within the system. The study is ...
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In this article, an investigation into the impact of radiative heat loss in a stockpile of combustible material is considered. The heat loss is due to exothermic chemical reaction when carbon containing material of the stockpile reacts automatically with oxygen trapped within the system. The study is modelled in a rectangular slab of thermal conductivity that varies with temperature and loses heat to the surrounding environment by radiation. The differential equations governing the problem are solved numerically using Runge-Kutta-Fehlberg (RKF) method coupled with shooting technique. The behaviour of each embedded kinetic parameter of the system due to variation with temperature, oxygen depletion (O2) and carbon dioxide emission (CO2), is analysed and results are graphically expressed and discussed appropriately. The results show that kinetic parameters which enhance exothermic chemical reaction correspondingly increase the temperature and CO2 emission of the combustion process. Copyright © 2018 VBRI Press.
Tarek S. Jamil; Eman S. Mansor
Abstract
A heterojunctionBiOI0.5Br0.5 was prepared for enhancing the photocatalytic performance of BiOX (X= Br or I) by facile method at room temperature using Bismuth Nitrate Bi(NO3)3.5H2O as Bismuth source. All prepared materials were fully identified by the required characteristics. The effect of heterojunction ...
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A heterojunctionBiOI0.5Br0.5 was prepared for enhancing the photocatalytic performance of BiOX (X= Br or I) by facile method at room temperature using Bismuth Nitrate Bi(NO3)3.5H2O as Bismuth source. All prepared materials were fully identified by the required characteristics. The effect of heterojunction as well as BiOBr and BiOI on the photocatalytic activities were studied through degradation of widely used endocrine disturbing compound, Bisphenol – A, in aqueous solution under commercial visible lamp. The percent removal of Bisphenol– A was 55%, 79% and 93% with BiOBr, BiOI and BiOI0.5Br0.5 respectively after 120 min irradiation time using 1.0 g/L dose of photocatalysts and pH10. Accordingly, heterostructure considered a promising method that can be used to enhance pure photocatalyst for degradation of organic pollutants in water. Copyright © 2018 VBRI Press.
Research Article
Gyanendra K. Pandey; Nilesh K. Pathak; R. P. Sharma
Abstract
Optical properties of Au metal nanoparticle have been studied in terms of extinction (scattering+absorption) at the resonance wavelength from UV to IR region. For the spherical geometry having radius 10nm, local electric field intensity distribution were studied at wavelength 615nm. This enhanced field ...
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Optical properties of Au metal nanoparticle have been studied in terms of extinction (scattering+absorption) at the resonance wavelength from UV to IR region. For the spherical geometry having radius 10nm, local electric field intensity distribution were studied at wavelength 615nm. This enhanced field has been couples in the SERS where we increase the sensitivity of the surface to detect a single biomolecule which is adsorbed at the surface of metal nanoparticle. The field profile was studied using COMOL-5.2 which works on the principle of electrodynamics in which the solution of Maxwell’s equation with certain boundary condition is solved. Optimized physical and geometrical parameters was suggested for the application in the field of chemical and biomedical instrument development for the purpose of drug detection and disease diagnosis for cancer detection at the early stage. Copyright © 2018 VBRI Press.
Prashant Thapliyal; Ajay Kumar; Gananath D.Thakre; Anil K. Jain
Abstract
Flow behavior of lubricants is largely determined by rheological properties that in turn influence their tribo-performance behavior. Rheological parameters can be influenced by dispersing MoS2 nano-particles in them. In order to study the effect of MoS2 nano-particles on tribological and rheological ...
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Flow behavior of lubricants is largely determined by rheological properties that in turn influence their tribo-performance behavior. Rheological parameters can be influenced by dispersing MoS2 nano-particles in them. In order to study the effect of MoS2 nano-particles on tribological and rheological properties of lubricants, two commercially available blended lubricants were selected as base oils with synthetic engine oils of SAE grades 5W40. They were blended with 0.15 and 0.2% by weight of functionalized nano-MoS2. Standard ASTM and IS procedures were used to determine physicochemical properties and tribo-performance behavior of oils respectively. Rheometer Physica MCR 301 from Anton-Paar Austria was used to determine the rheological parameters of lubricants. A marginal reduction in friction to the tune of 3% has been observed for the 0.2 wt% of MoS2 nano-particles in the tested lubricants while anti-wear properties showed significant enhancement by 20% indicating better anti wear properties of nano-MoS2. Extreme pressure properties of MoS2 particles play an important role in defining its anti-wear properties as it has significant load bearing properties. Rheological data reveal that tested MoS2 nano-fluids show shear thinning behavior at all tested temperatures and rheological behavior improved with the addition of MoS2 nanoparticles due to increase in apparent yield stress. Copyright © 2018 VBRI Press.
Ranu Pal; Sandeep Kumar Singh; M.J. Akhtar; Kamal K. Kar
Abstract
Efforts to use microwaves in material processing are gradually increasing. However, the phenomenon associated with the processing is less understood. The conversion of electromagnetic energy into heat depends largely on the dielectric properties of the material being treated. Therefore, the fundamental ...
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Efforts to use microwaves in material processing are gradually increasing. However, the phenomenon associated with the processing is less understood. The conversion of electromagnetic energy into heat depends largely on the dielectric properties of the material being treated. Therefore, the fundamental knowledge of these properties is essential for processing of materials using microwaves. In this study, first the dielectric evolution of silicon carbide (SiC) infused epoxy nanocomposites prepared at room temperature with 0-0.3 wt% content of SiC was measured. Secondly, the dielectric properties of the prepared nanocomposites after heating for 10 min in microwaves at a power of 500 W were investigated in order to see the effect of microwave curing. The dielectric properties of all the samples were measured at the microwave frequency of 2.45 GHz using the advanced cavity perturbation method attached to a vector Network Analyzer (VNA). The results indicate that the dielectric properties of the resultant nanocomposites increase with the increase in SiC content as compared to the neat epoxy sample. However, the dielectric properties were found to be decrease after microwave curing signaling the maximum possible extent of curing. This indicates that reinforcement of SiC nanoparticles in epoxy makes them ideal candidates for efficient microwave curing of nanocomposites. Lastly, the determination of thermal properties also confirms the maximum possible extent of curing of epoxy using SiC as nanofillers. Copyright © 2018 VBRI Press.
Sumali Bansal; . Priyanka; Rajiv Bhandari; Keya Dharamvir
Abstract
Gold clusters are known to have size dependent geometries. The study of golden cages of different sizes and dimensions has gained momentum in recent years as they can accommodate guest atoms to form a new kind of endohedral structure. We will be studying the doping of gold tubular cages with transition ...
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Gold clusters are known to have size dependent geometries. The study of golden cages of different sizes and dimensions has gained momentum in recent years as they can accommodate guest atoms to form a new kind of endohedral structure. We will be studying the doping of gold tubular cages with transition metal (TM=Ag, Cu and Au). Their geometrical structures, relative stabilities, binding energies and bond lengths are studied using Model Potential approach- Gupta Potential (GP). AuAg and AuCu have been chosen because they may be expected to show different behaviors. As far as our knowledge no such work has been reported earlier. It is observed that doping of Ag and Cu atom at the centre of planar Au6 results in a three dimensional geometry. The atom-atom interaction potential predicts the dominance of the finite size effect as the number of Cu and Ag atoms increases along with the size of gold tubular cage. Copyright © 2018 VBRI Press.
Pradyumna Mogre; Sharanabasava V. Ganachari; Jayachandra S. Yaradoddi
Abstract
Polyaniline fibres were synthesized by chemical oxidative polymerization using different ratios of monomers in the feed in HCl medium. The synthesized polymers were characterized by employing Fourier transform infrared, UV-visible, X-ray diffraction techniques for understanding the details of the structure ...
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Polyaniline fibres were synthesized by chemical oxidative polymerization using different ratios of monomers in the feed in HCl medium. The synthesized polymers were characterized by employing Fourier transform infrared, UV-visible, X-ray diffraction techniques for understanding the details of the structure of the synthesized polymers. Morphological, thermal, and electrical conductivity of the as synthesized polymers were also studied by employing scanning electron microscopy, thermogravimetric analysis, and electrical conductivity, respectively. A three-step thermal degradation was observed for the polymer. It was observed that yield and intrinsic viscosity of polymer is not regularly dependant on monomer concentration in the feed. The polyaniline show better conductivity than Polythiophene. Copyright © 2018 VBRI Press.
Deepti R. Kulkarni; Narasimha H. Ayachit; Raviraj M. Kulkarni
Abstract
We report an inexpensive TiO2 based quantum dot solar cell (QDSSC) with improved power conversion efficiency prepared by simple techniques. Barium doped zinc sulfide has been successfully deposited on cadmium sulfide quantum dots (QDs) by simple successive ion layer adsorption and reaction (SILAR) technique. ...
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We report an inexpensive TiO2 based quantum dot solar cell (QDSSC) with improved power conversion efficiency prepared by simple techniques. Barium doped zinc sulfide has been successfully deposited on cadmium sulfide quantum dots (QDs) by simple successive ion layer adsorption and reaction (SILAR) technique. The Barium doped zinc sulfide is utilized as a passivation layer in the QDSSC, which helped in better charge separation. The copper sulfide (Cu2S) and reduced graphene oxide deposited on FTO was used as a counter electrode. The developed QDSSC showed superior performance when tested with AM 1.5 solar simulator using sulfide/Polysulfide electrolyte. The photoconversion efficiency of FTO/TiO2/CdS/BaZnS/Cu2S-Graphene oxide is better than that of FTO/TiO2 /CdS/ZnS/Cu2S-Reduced Graphene oxide. Copyright © 2018 VBRI Press.