Sagar M. Mane; Sanjay G. Chavan; Pravin M. Tirmali; Dadasaheb J. Salunkhe; Chandrakant B.Kolekar; Shrinivas B. Kulkarni
Abstract
Present paper reports on synthesis and characterization of x[Co0.9Ni0.1Fe2O4]-(1-x)[Ba(Zr0.2Ti0.8)O3] multiferroic magneto-dielectric composite of ferrite and ferroelectric phase for x=0.1, 0.2 and 0.3 via hydroxide co-precipitation method. The well compacted disc shape samples of the MD composites ...
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Present paper reports on synthesis and characterization of x[Co0.9Ni0.1Fe2O4]-(1-x)[Ba(Zr0.2Ti0.8)O3] multiferroic magneto-dielectric composite of ferrite and ferroelectric phase for x=0.1, 0.2 and 0.3 via hydroxide co-precipitation method. The well compacted disc shape samples of the MD composites are sintered with microwave sintering technique at 1100°C. These composites are investigated for their structural, micro-structural, dielectric, ferroelectric and magneto-dielectric properties. X-ray diffraction shows the presence of the peaks corresponding to both ferroelectric and ferrite phases in the composites. Temperature dependent dielectric spectra gives the two anomalies one at lower temperature (below 50°C) corresponds to the ferroelectric transition temperature and other at the higher temperature (above 350°C) corresponding to magnetic transition. The variation of dielectric constant and loss tangent with applied magnetic field between 0-1 tesla in the frequency range of 500 Hz to 1 MHz are investigated. Dielectric constant possesses contribution due to magnetic field dependent interfacial polarization and variations due to the induced stress which can be explained on the observed MD effect.
Priyanka Goyal; Sudha Pal; Umesh Chandra Bind; Yogesh Kumar Sharma
Abstract
The present works gives the information about the structural and physical analysis of borosilicate glasses with praseodymium ions. Glass specimen were prepared with the chemical composition (50-x) B2O3 - (10+x) SiO2 – 10Na2O – 20PbO – 10ZnO - 1Pr6O11 (where x= 0, 5, 10, 15, 20, 25, ...
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The present works gives the information about the structural and physical analysis of borosilicate glasses with praseodymium ions. Glass specimen were prepared with the chemical composition (50-x) B2O3 - (10+x) SiO2 – 10Na2O – 20PbO – 10ZnO - 1Pr6O11 (where x= 0, 5, 10, 15, 20, 25, 30, 35, 40) by standard method. The composition of the glass specimens was finalized by EDX. The presence of various stretching and bending vibrations are confirmed with the help of FTIR analysis. The borate network of the present glass samples lies in the wavelength range 500-1600 cm-1 and confirmed by the TEM image. Anti-symmetric stretching vibrations with three non-bridging oxygens of B – O – B groups are present at ~1488 cm-1. XRD were recorded for confirmation of the amorphous nature of the samples. The SEM image confirmed the XRD results. Various physical parameters have been calculated for knowing the structure of present glass with increasing the SiO2 concentration. Oxygen Packing Density (OPD) decreases with increase in SiO2 concentration. Decrease in the value of OPD shows that glass structure is now loosely packed. Absorption spectra of the glass samples were recorded in UV-VIS/NIR region. JO intensity, Racah, Slater-Condon, Lande parameters have been computed. W2 parameter gives information about the glass structure and depends upon the Pr – O bond in the host matrix. Optical energy band gap and Urbach’s energy values were calculated for exploring the electronic band structure. Copyright © 2017 VBRI Press.
Anil S. Meshram; Ompraksh P. Chimankar; Yashwantrao D. Tembhurkar
Abstract
Thin films of CuInTe2(1-x)S2x were grown by spray pyrolysis and develop thin films on glass substrate at 350C by varying proportion x in the range of 0.25. Aqueous solutions of cupric chloride, indium tri-chloride, thio-urea and tellurium tetra-chloride mixed in proper composition x and studies their ...
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Thin films of CuInTe2(1-x)S2x were grown by spray pyrolysis and develop thin films on glass substrate at 350C by varying proportion x in the range of 0.25. Aqueous solutions of cupric chloride, indium tri-chloride, thio-urea and tellurium tetra-chloride mixed in proper composition x and studies their electrical properties of all these films. The resistivity of the films was measured for temperature ranging from 77 K to 473 K. The activation energies values were calculated from Arrhenius plot. At very low temperature a variable range hopping conduction mechanism appears to be operative. Surface of thin films has been studied by Scanning Electron Microscope. 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.
Sharmistha Anwar; Barada K. Mishra; Shahid Anwar
Abstract
Thermoelectric thin films of Bi2Te3 and Sb2Te3 were deposited by using sputtering technique. Structural characterizations of as deposited films were done by using X-ray diffraction (XRD), Energy Dispersive X-ray Analysis and electrical properties have been evaluated at room temperature by Seebeck coefficient ...
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Thermoelectric thin films of Bi2Te3 and Sb2Te3 were deposited by using sputtering technique. Structural characterizations of as deposited films were done by using X-ray diffraction (XRD), Energy Dispersive X-ray Analysis and electrical properties have been evaluated at room temperature by Seebeck coefficient and electrical resistivity measurement. These sputtered films were established to be polycrystalline and of desired single phase in nature with stoichiometric composition. The Seebeck coefficient and electrical resistivity of p-type Sb2Te3 thin film and n-type Bi2Te3 thin films were found to be about 111 μV/K, 8.25×10-5 Ω- m and −98.52μV/K, 5.87×10-6 Ω-m, respectively whereas to that of n-type Bi2Te3-Sb2Te3 multilayer having 5BL combination is −145μV/K, 9.31×10-5 Ω-m and 10BLcombination is −170 μV/K, 9.86×10-5 Ω-m. The power factor value has increased reasonably well in case of multilayer as compared to that of individual single layer, maximum power factor value 2.95×10-3 W/m K2 has been achieved for 10BL combination. These results indicate that good quality antimony telluride, bismuth telluride and their multilayer thin films can be grown easily by using sputtering technique. It also suggests that these types of nano-structuring (multilayer structure) in these categories of materials can be promissory engineering concept for the fabrication of micro-Peltier modules.
Nidhi Gupta; Rakhi Grover; Dalip S. Mehta; Kanchan Saxena
Abstract
Here we present fabrication of one dimensional photonic band gap structure (1D-PBG) based on periodic layers of silver and magnesium fluoride (MgF2) for tuning the emission of polyfluorene derivative, Poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO). Transmittance measurements were used to characterize the ...
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Here we present fabrication of one dimensional photonic band gap structure (1D-PBG) based on periodic layers of silver and magnesium fluoride (MgF2) for tuning the emission of polyfluorene derivative, Poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO). Transmittance measurements were used to characterize the photonic band gap. 1D-PBG structure with varying thickness of silver was fabricated on the back side of PFO coated glass substrate. Photoluminescence studies confirmed that blue emission was enhanced while the secondary peaks were suppressed. Photoluminescence spectra shows that the blue to green peak intensity ratio was improved by 1.7 times approximately with PBG. These type of PBG structures can be used to enhance the color purity of PFO based blue organic light emitting diodes. Copyright © 2017 VBRI Press.
Prahlad K. Baruah; Ashwini K. Sharma; Alika Khare
Abstract
In this paper, the effect of incident laser energy on the localized surface plasmon resonance (LSPR) and size of copper (Cu) nanoparticles (NPs) synthesized via pulsed laser ablation of copper in distilled water (DW) is reported. The absorption spectra show plasmon peak in the visible spectral region. ...
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In this paper, the effect of incident laser energy on the localized surface plasmon resonance (LSPR) and size of copper (Cu) nanoparticles (NPs) synthesized via pulsed laser ablation of copper in distilled water (DW) is reported. The absorption spectra show plasmon peak in the visible spectral region. The increase in the laser energy from 30 mJ to 70 mJ of the second harmonic of a Q-switched Nd:YAG laser induces a blue shift in the plasmon peak from 627 nm to 617 nm along with its broadening from 180 nm to 242 nm, respectively. These observations have been explained on the basis of the effect of the small size of the NPs formed. The Transmission electron microscope (TEM) substantiates these results as it shows the decrease in the average particle size of the NPs from ~20 nm to ~7 nm with the increase in the incident laser energy from30 mJ to 70 mJ, respectively. By merely increasing the laser energy, a size-dependent LSPR has been achieved and this can be used as an effective way to control the size of Cu NPs and hence LSPR. Copyright © 2017 VBRI Press.
Rajib Saha; Avishek Das; Anupam Karmakar; Sanatan Chattopadhyay
Abstract
Vertically oriented ZnO nanowires are grown on p-Si substrate by employing two-step sequential chemical bath deposition technique. The ZnO nanowire exhibits n-type doping due to the presence of oxygen vacancies. The electrical characterizations of n-ZnO NWs/p-Si heterojunction diodes exhibit a self-rectifying, ...
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Vertically oriented ZnO nanowires are grown on p-Si substrate by employing two-step sequential chemical bath deposition technique. The ZnO nanowire exhibits n-type doping due to the presence of oxygen vacancies. The electrical characterizations of n-ZnO NWs/p-Si heterojunction diodes exhibit a self-rectifying, threshold resistive switching behavior. Such switching behavior is explained by oxygen vacancy assisted conducting filament formation mechanism. The relevant charge transport is governed by TC-SCLC and multistep recombination-tunneling processes through the interface traps. Threshold-voltage for resistive switching is observed to be increasing with increasing bias sweep rate. The device shows superior memory endurance for forward and reverse voltage sweep of 50 cycles in fast sweep mode. The ratio of HRS to LRS resistances shows one order of difference. The retention time of such resistive switching memory is recorded to be 4000 seconds, suggesting its non-volatile functionality. Thus, the n-ZnO NWs/p-Si heterojunction can be employed for fabricating promising non-volatile memory devices with excellent endurance and retentions. Copyright © 2018 VBRI Press.
Ujjal Chowdhury
Abstract
Room temperature multiferroicity has been in the centre of interest for last few years due to its enormous potential to be applied as real multifunctional device. LuFeO3 is a potential candidate as room temperature multiferroic1, which offers strong multiferroic coupling at room temperature [1]. Presence ...
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Room temperature multiferroicity has been in the centre of interest for last few years due to its enormous potential to be applied as real multifunctional device. LuFeO3 is a potential candidate as room temperature multiferroic1, which offers strong multiferroic coupling at room temperature [1]. Presence of ferroelectric polarization is observed in Mn-doped LuFeO3 also. The main area of restriction is its low polarization, which is to be improved before it can be applied in real devices. In order to do that proper understanding of the mechanism of generation of ferroelectricity is needed. In order to do that we observed that, the ferroelectric and multiferroic properties at room temperature, in orthorhombic distorted perovskite LuFeO3 are greatly affected by Cu or Mn doping. If we replace Fe+3 ion (Ionic Radius=126) with some amount another ion of increasing ionic radius Mn+2 (Ionic Radius=127) and Cu+2 (Ionic Radius = 128) the ferroelectric properties are greatly affected as evidenced by the P-E Hysteresis loop measurements. The appearance of ferroelectricity in LuFeO3 could be attributed to the spin current based model as proposed by katsura et al. [3]. The effect of Cu and Mn doping also can be explained with the Spin current based model [3]. Copyright © 2017 VBRI Press.
Paula Louro; Manuela Vieira; Manuel A. Vieira; J. Costa
Abstract
We propose the use of Visible Light Communication (VLC) for localization services and navigations. The proposed lighting system supplies the dual function of lighting and data transmission. It uses commercial RGB white LEDs for the generation of the light and of the modulated optical signals that are ...
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We propose the use of Visible Light Communication (VLC) for localization services and navigations. The proposed lighting system supplies the dual function of lighting and data transmission. It uses commercial RGB white LEDs for the generation of the light and of the modulated optical signals that are transmitted in free space using an on-off coding scheme. The red, green and blue emitters of white LEDs are independently modulated, transmitting each different information. The photodetector is a multilayered device based on a-SiC:H, designed for the detection of visible optical light. The generated electrical signal by the photodetector is strictly related to the input optical excitation and its demodulation and decode enables the identification of the input light signals that carry the information necessary to perform the positioning and navigation tasks. The photodetector works as an active optical filter presenting self-amplification at selectable wavelengths. It is a multilayered device composed by two stacked pin photodiodes fabricated between conductive transparent electrical contacts. The positioning system includes multiple, identical navigation cells. The decoded signal by the photodetector identifies the input emitter cell and supplies enhanced accuracy within the spatial region covered by the cell. The methodology used for the photocurrent signal processing involves Fourier transform analysis for frequency identification and the use of a photodetector with spectral selective properties of wavelength identification. An algorithm to decode the information is established and the positioning accuracy is discussed. The experimental results, confirmed that the proposed VLC architecture is suitable for the intended application. Copyright © 2018 VBRI Press.
Anju .; Ashish Agarwal; Praveen Aghamkar
Abstract
Barium substituted bismuth ferrite (Bi0.8Ba0.2FeO3) was synthesized using ethylene glycol based sol-gel method followed by heat treatment at 800°C for 15 min. In order to study the effect of barium substitution on structural parameters the rietveld refinement of the sample was performed. Structural ...
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Barium substituted bismuth ferrite (Bi0.8Ba0.2FeO3) was synthesized using ethylene glycol based sol-gel method followed by heat treatment at 800°C for 15 min. In order to study the effect of barium substitution on structural parameters the rietveld refinement of the sample was performed. Structural transition from the rhombohedral perovskite (ABO3) crystal structure to pseudo-cubic has been confirmed. Ba substitution at Bi site suppresses the secondary phases of BiFeO3 such as Bi2Fe4O9, Bi25FeO39 etc. The crystallite size of the prepared barium substituted BiFeO3 (BBFO) nano-multiferroic calcined at 800°C is found to be ~ 20 nm. The functional groups in the calcined sample were identified by FTIR analysis. TG-DSC analysis of the sample has also been performed. It is expected that structural changes made by barium in BiFeO3 would also affect its magnetic behavior. Copyright © 2017 VBRI Press.
Nasrullah Shah; Touseef Rehan; Muhammad Balal Arain; Rabia Tabassum
Abstract
The addition of appropriate additives can change the properties of the polymer matrix. Nanocomposites are useful because of its high aspect ratio. Selection of additives which can make a cheaper and multifunctional material is one of the major issues. ZnO nanoparticles can be used as an additive in preparing ...
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The addition of appropriate additives can change the properties of the polymer matrix. Nanocomposites are useful because of its high aspect ratio. Selection of additives which can make a cheaper and multifunctional material is one of the major issues. ZnO nanoparticles can be used as an additive in preparing biocompatible and biodegradable nanocomposite which would have several analytical and biomedical applications. ZnO nanoparticles are multifunctional materials and in recent years they drawn an increasing attention because of its physical and chemical stability, high catalysis activity, effective antibacterial and bactericide function and intensive UV and IR absorption. Hence considering the above reasons, in the present study the incorporation of different amounts of ZnO powder inside the P oly(acrylonitrile-co-acrylic acid) is done by a low cost physico-mechanical method to prepare polymer nanocomposite for multiple purposes. The as synthesized ZnO based Poly(acrylonitrile-co-acrylic acid) composite sheets were characterized by various analytical techniques such as FTIR, Raman Spectroscopy, SEM, XRD and TGDTA. The analyses indicated the uniform dispersion of ZnO nanoparticles inside the polymer matrix resulted in crystalline structure which resulted in improved thermal stability and low water holding capacity and swelling ratio. The as synthesized nanocomposites were effectively utilized for biological activities. Copyright © 2018 VBRI Press.
Rabesh Kumar Singh; Anuj Kumar Sharma; Amit Rai Dixit; Arun Kumar Tiwari; Amitava Mandal
Abstract
Health and environmental concerns about the use of excessive conventional cutting fluids during conventional machining has led to the development of a new type of cutting fluid. Inefficient disposal of industrial cutting fluids during wet machining also reduces the use of conventional cutting fluid. ...
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Health and environmental concerns about the use of excessive conventional cutting fluids during conventional machining has led to the development of a new type of cutting fluid. Inefficient disposal of industrial cutting fluids during wet machining also reduces the use of conventional cutting fluid. Nano-material mixed cutting fluids have shown superior thermal properties and tribological properties. In the present work, different nanofluids are prepared by suspension of Titanium dioxide (TiO2), Silicon oxide (SiO2) and Aluminum oxide (Al2O3) nanoparticles in vegetable oil and water-based emulsion at room temperature in different volumetric concentrations. The viscosity and density of the developed nanofluids are measured at different temperatures for different nanoparticle volumetric concentrations. From the experimental results, it has been found that with the increase of nanoparticle concentration in base fluid, enhanced the its viscosity and density. Furthermore, addition of nanoparticles at 25 ºC enhances viscosity more compared to its addition at higher temperatures. For an increase of concentration from 0.25% to 3%, enhancement in viscosity of Al2O3, SiO2 and TiO2 nanofluids is observed as 41.6%, 43.75% and 35.55%, respectively, while for higher temperatures almost constant improvement of 25%, 24% and 30% is observed for Al2O3, SiO2 and TiO2 nanofluids, respectively. The viscosity and density of three different nanofluids are also compared. Results showed that newly prepared Al2O3 based nanofluid exhibits better properties than TiO2 and SiO2 based nanofluids. Copyright © 2017 VBRI Press.
Naveen M. Tripathi; S. S. Mallick
Abstract
This paper presents results of an ongoing investigation into the modelling of pressure losses through bends during pneumatic conveying of fly ash. For the reliable design of pneumatic conveying systems, an accurate prediction of bend pressure drop is of paramount importance as the same can significantly ...
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This paper presents results of an ongoing investigation into the modelling of pressure losses through bends during pneumatic conveying of fly ash. For the reliable design of pneumatic conveying systems, an accurate prediction of bend pressure drop is of paramount importance as the same can significantly influence the total pipeline pressure loss. In the present study, seven existing bend models (Schuchart, Singh and Wolf, Rossetti, Westman, Bradley, Pan, Pan and Wypych, Das and Meloy models) were used to predict the total pipeline pressure drop for conveying fine fly ash through two test rigs: 63.5 mm I.D. x 24 m long and 54 mm I.D. x 70 m long. Comparisons between the predicted pneumatic conveying characteristics using the seven bend models and the experimental data have shown that the trends and values of the total pipeline pressure drops can significantly vary depending on the choice of bend model. While some models have provided increasing values of bend pressure drops with rise in air flows, some other models have produced reversed characteristics. It is concluded that the parameter grouping used in the existing bend models are not generally capable of predicting bend pressure drop reliably and therefore, further research is required to better understand the flow mechanisms of gas-solids flows across bends towards developing improved bend models. Copyright © 2017 VBRI Press.
Susai Rajendran; R Joseph Rathish; S Santhana Prabha
Abstract
Self-assembling molecules form protective layers on metal surfaces Self assembled nanofilms of adipic acid, N-cetyl-N,N,N-trimethyl ammonium bromide, Tween- 60, Sodium dodecyl sulphate and an aqueous extract of banana peel have been formed on the surface of carbon steel ...
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Self-assembling molecules form protective layers on metal surfaces Self assembled nanofilms of adipic acid, N-cetyl-N,N,N-trimethyl ammonium bromide, Tween- 60, Sodium dodecyl sulphate and an aqueous extract of banana peel have been formed on the surface of carbon steel by the immersion method. The formation of the nanofilms has been confirmed by Fourier Transform Infrared spectral study and Atomic Force Microscopy Study. The corrosion inhibitive nature of the protective film has been estimated by the classical weight loss method and electrochemical study such as polarization study. The hydrophobic nature of the protective film has been investigated by measurement of contact angles of the protective films. The hydrophobic surfaces may find application in various exciting fields such as corrosion protection, raincoats, water proof surfaces and biomaterials. Copyright © 2017 VBRI Press.
Govind Reddy.Y; Sadananda Chary.A; Awasti. A.M; Narender Reddy.S
Abstract
The composite solid electrolyte systems, (1-x)Pb(NO3)2:xCeO2 (x= 0, 0.02, 0.03, 0.04, 0.05 and 0.08), have been investigated by XRD for structural properties, SEM with EDS for morphological studies and Electrical properties through impedance spectroscopy. The frequency and temperature dependence of ac ...
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The composite solid electrolyte systems, (1-x)Pb(NO3)2:xCeO2 (x= 0, 0.02, 0.03, 0.04, 0.05 and 0.08), have been investigated by XRD for structural properties, SEM with EDS for morphological studies and Electrical properties through impedance spectroscopy. The frequency and temperature dependence of ac conductivity, dielectric constant and dielectric loss were measured between the temperatures 30oC to 340oC in the frequency range 1Hz to 10MHz. The complex impedance data is analyzed in conductivity, permittivity and electric modulus formalism in order to through light on transport mechanism. Variation of ac conductivity against frequency suggests the response obeying universal power law. The dynamics of conducting ion is studied through Jonscher’s Universal power law. The parameters of n and A of Jonscher’s Universal law suggest these values are strongly temperature sensitive. The variation of dielectric permittivity, loss, and modulus spectra were found to be consistent with conductivity. Impedance, dielectric and modulus analysis had indicated the non-Debye behavior in these composites. The relaxation phenomena were observed in all formalisms. Copyright © 2017 VBRI Press.
Bikash Mandal; Indranarayan Basumallick; Susanta Ghosh
Abstract
Present study reports an easy and cost-effective method of synthesis of Li4Fe(CN)6 cathode from K4Fe(CN)6.3H2O and LiClO4 in aqueous medium for its use in lithium-ion battery. The synthesized Li4Fe(CN)6 is characterized by UV-Vis, FTIR and cyclic-voltammetry studies. A special laboratory model lithium-ion ...
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Present study reports an easy and cost-effective method of synthesis of Li4Fe(CN)6 cathode from K4Fe(CN)6.3H2O and LiClO4 in aqueous medium for its use in lithium-ion battery. The synthesized Li4Fe(CN)6 is characterized by UV-Vis, FTIR and cyclic-voltammetry studies. A special laboratory model lithium-ion battery is designed, where aqueous Li4Fe(CN)6 solution acts as a cathode, metallic lithium as anode and 1 molar solution of LiPF6 dissolved in water immiscible ionic liquid, 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) as electrolyte. The cell exhibits an open circuit potential of 3.12 volt and a good charge-discharge cycling behaviour. The cell delivered a maximum discharge capacity of 86 mAhg-1 (theoretical capacity 112 mAhg-1) at 0.2 C rates with an average discharge potential of 2.1 volts. Although the ionic liquid is a little bit cost intensive, but the easy synthesis methodology with the cheapest raw materials and overall cycling efficiency, makes this technology available as a green economical energy storage device in the current battery industry. Copyright © 2017 VBRI Press.
Hamood Al Kharusi; Mozhgan Svensson; Babak Salamatinia; Bahman Amini Horri
Abstract
NiO/YSZ (nickel oxide / yttria-stabilized zirconia) is the state-of-the-art anode composite for fabrication of high-temperature solid oxide fuel cells (SOFCs). In this study, nanocomposite powder of NiO/YSZ was synthesized by thermal treatment of the gel beads formed by extrusion dripping of sodium alginate ...
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NiO/YSZ (nickel oxide / yttria-stabilized zirconia) is the state-of-the-art anode composite for fabrication of high-temperature solid oxide fuel cells (SOFCs). In this study, nanocomposite powder of NiO/YSZ was synthesized by thermal treatment of the gel beads formed by extrusion dripping of sodium alginate solution into an aqueous solution of Ni+2, Y+3, and Zr+4. The NiO/YSZ nanocomposite powder was prepared by calcination (thermal decomposition) of the dried beads in a muffle furnace at 400°C-600°C for 6 hours. The as prepared powders were characterised by TGA, XRD, FESEM, and TEM techniques. The TGA results of the dried beads showed that the thermal degradation begins at 135°C which is followed by a total mass loss of around 75.0% at 600°C. The morphology analysis of the sample (by FESEM and TEM images) showed a relatively uniform particle size distribution of the powder with an average particle size of 5-25 nm that was confirmed by the XRD crystal size calculations. The electrochemical performance measurement of the fabricated cell using the synthesized NiO/YSZ showed a maximum power density of 1143 mW/cm2 at 850°C under hydrogen stream at 20 ml/min. Copyright © 2017 VBRI Press.
Lincy Varghese; VVL. Kanta Rao; Lakshmy Parameswaran
Abstract
The microstructure and time dependent properties of nanosilica (nS) added high performance concrete (nS-HPC) were investigated, and a comparison of these properties with those of microsilica (mS) added high performance (mS-HPC) concrete and a reference concrete (RefCon) are presented. 3% colloidal nS ...
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The microstructure and time dependent properties of nanosilica (nS) added high performance concrete (nS-HPC) were investigated, and a comparison of these properties with those of microsilica (mS) added high performance (mS-HPC) concrete and a reference concrete (RefCon) are presented. 3% colloidal nS and 7.5% powder mS were used to make nS-HPC and mS-HPC, respectively. The scanning electron microscopic image of the 90 days’ nS-HPC revealed that the quantity of Ca(OH)2 present was almost negligible and the concrete attained a finer and compact microstructure with finer C-S-H as compared to that of other two concretes. The creep and drying shrinkage of the nS-HPC were found to be higher than those of RefCon and mS-HPC. However, the observed drying shrinkage of all the concrete mixes was found to be conforming with the estimates made from Indian Road Congress (IRC):112-2011 model, while on the other hand, the creep coefficients of mS-HPC and nS-HPC was found to be higher than the corresponding estimated creep coefficients, and the same were found to be higher by 13.3% and 18.2%, respectively, at 100 days. The increase in drying shrinkage and creep of both the high-performance concretes (HPC) than that of RefCon may be attributed to higher amounts of gel water present in the finer C-S-H produced due to pozzolanic action. The results from the study indicates suitability of nS-HPC for construction of bridge structures. Copyright © 2017 VBRI Press.
Ashok CH; Venkateswara Rao K; Shilpa Chakra CH
Abstract
Metal oxide nanomaterials shows variety of applications in the field of optoelectronics, semiconductors, catalysis, coatings, solar cells, ceramics, spintronic, biological and sensors. Present paper deals with ZnO/CuO nanocomposite material synthesis, characterization and humidity sensor application. ...
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Metal oxide nanomaterials shows variety of applications in the field of optoelectronics, semiconductors, catalysis, coatings, solar cells, ceramics, spintronic, biological and sensors. Present paper deals with ZnO/CuO nanocomposite material synthesis, characterization and humidity sensor application. Novelty of this work is to know the high sensitivity of two conjugated n and p type semiconductor metal oxide nanocomposite at various temperatures. Nanocomposite materials are synthesized by microwave-assisted method with the help of room temperature ionic liquid (RTIL). Zinc acetate, Copper acetate, Sodium hydroxide and 1-butyl-3-methyl-imidazolium-tetrafluoroborate ([BMIM]BF4) were used as initial precursors. The obtained nanocomposite materials were annealed at different temperatures such as 500 °C, 600 °C, 700 °C and 800 °C. These annealed nanocomposite materials have been characterized by X-ray diffractometer (XRD), Particle size analyzer (PSA), Scanning electron microscope (SEM), Energy dispersive x-ray spectrometer (EDS) and Thermo gravimetric and differential thermal analyzer (TG/DTA) for analyze crystal structure, average particle size, surface morphology, elemental analysis and weight loss respectively. The humidity sensor application was predicted by controlled humidity chamber, hygrometer and digital multi meter. The resistance of the sensing element measured with respect to relative humidity from 10% to 98%. The sensitivity of the nanocomposite material increased from 1.7 % to 2.3 % along with increasing of annealing temperature 500 °C to 800 °C. ZnO/CuO nanocomposite annealed at 800 °C shows high sensitivity means it is also having good response and recovery times.
Sangita Patari; Aparna Nath
Abstract
In this article, our intention is to observe the mesophase textures of a liquid crystal (LC) compound 4-nonyloxybenzoic Acid (9OBA) in an attempt to understand the nature of dramatic changes of the mesophase transition textures with temperature. The studies of mesophase textures were carried out by using ...
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In this article, our intention is to observe the mesophase textures of a liquid crystal (LC) compound 4-nonyloxybenzoic Acid (9OBA) in an attempt to understand the nature of dramatic changes of the mesophase transition textures with temperature. The studies of mesophase textures were carried out by using polarizing optical microscope (POM). Mesophase transition temperatures and their corresponding enthalpy changes (during heating) are experimentally deduced from differential scanning calorimetry (DSC). Higher value of enthalpy changes has been observed for the solid crystalline to Smectic C (SmC) transition. The compound 9OBA is found to exhibit nematic and SmC mesosphase and may be useful for the projection display since it exhibits high clearing temperature. Copyright © 2017 VBRI Press.
J. Dhanalakshmi; D. Pathinettam Padiyan
Abstract
GdxTi1-xO2 nanocomposites with x=0.00, 0.02, 0.04, 0.06, 0.08 & 0.10 were prepared through sol-gel method. The samples were characterized using X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), High resolution scanning electron microscope (HR-SEM), Raman spectroscopy and photoluminescence ...
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GdxTi1-xO2 nanocomposites with x=0.00, 0.02, 0.04, 0.06, 0.08 & 0.10 were prepared through sol-gel method. The samples were characterized using X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), High resolution scanning electron microscope (HR-SEM), Raman spectroscopy and photoluminescence spectroscopy (PL). The XRD pattern and Raman spectra confirmed the presence of crystalline nature and phase pure anatase tetragonal system. The average crystallite size of the samples was between 10 to 18 nm. HR-SEM images indicated the formation of spherical like particles of GdxTi1-xO2 nanocomposites. An obvious reduction in particle size of GdxTi1-xO2 nanocomposites were noticed while comparing the SEM images of bare TiO2 and composite samples. Coupling of Gd is responsible for slight blue shift in absorption edge. The presence of oxygen vacancies is confirmed in Raman and PL spectra. These oxygen vacancies potentially trap electrons and restrict the electron-hole recombination and thus improve the photocatalytic reactions.
Ramakanth Illa; Jaroslav Hamrle; Jaromir Pištora
Abstract
Nanostructured thin films of MnFe2O4 were fabricated using chemical approach. Structural, magnetic, optical and magneto-optical properties of the films have been investigated using XRD, AFM, VSM, spectroscopic ellipsometry and MOKE spectroscopy. Structural evaluation of the thermally annealed films showed ...
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Nanostructured thin films of MnFe2O4 were fabricated using chemical approach. Structural, magnetic, optical and magneto-optical properties of the films have been investigated using XRD, AFM, VSM, spectroscopic ellipsometry and MOKE spectroscopy. Structural evaluation of the thermally annealed films showed crystalline phase and spinel structure along with appearance of textured nano-crystallites at the annealing temperature (Ta) of 500 °C and above. Surface morphology of the films annealed at 600 oC was characterized using AFM and the size of MnFe2O4 particles was observed to be 70 – 180 nm with ellipsoidal morphology and the surface roughness was found to be 8 nm. Hysteresis loops of the ferrite films indicated ferromagnetic behavior for annealing temperature of 400 oC and above, with a small contribution of paramagnetic nature arising from its oxide. The films showed a semiconducting behavior for the annealing temperature (Ta) ranging from 400 - 600 oC. The magneto-optical response is found to be small, i.e., one order less when compared to CoFe2O4 or metallic Fe, Co films. The maximum magneto-optical response from MnFe2O4 thin films is found for Ta = 400 oC, i.e. for incomplete spinel structure. As the material used for making the thin film coating is of the order of very few milligrams, these highly responsive films could be used as magnetic sensors. Copyright © 2017 VBRI Press.
Deepak M. Kapse; Pradnya Parab; Sangita Bose; H. Muthurajan
Abstract
Due to the toxicity of lead, there is an urgent necessity to develop lead-free alternatives to replace the currently dominant lead-based piezoelectric such as Pb(Zr,Ti)O3 (PZT). Na0.5K0.5NbO3 based piezoelectric nanomaterial are promising because of their relatively high Curie temperatures as well as ...
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Due to the toxicity of lead, there is an urgent necessity to develop lead-free alternatives to replace the currently dominant lead-based piezoelectric such as Pb(Zr,Ti)O3 (PZT). Na0.5K0.5NbO3 based piezoelectric nanomaterial are promising because of their relatively high Curie temperatures as well as good piezoelectric coefficients among the non-lead piezoelectrics. We have successfully synthesized 3-dimensional perovskite nanocubes of functional ternary transition-metal oxide of sodium potassium niobate Na0.5K0.5NbO3 by using novel synthesis method. We have carried out resistance and impedance spectroscopy studies at low temperature using two probe technique. For this electrical measurement, we have used CCR system. There has been much interest in the texturing of electro ceramics, due to the possibility of achieving enhanced electrical properties. A major purpose for this electrical characterization study is to examine how Na0.5K0.5NbO3 (NKN) pellet behaves under low temperature. Copyright © 2017 VBRI Press.
Pawan K. Kaul; A. Joel Samson; I V M V Enoch; Paulraj Mosae Selvakumar
Abstract
In this report, we have explored the thermal stability and flammability of unsaturated polyester resin (UP) nano-composites blended with flame retardant trixylenyl phosphate (TXP) and nano-filler dodecyl sulphate intercalated magnesium aluminum layered double hydroxide (MgAlDS LDH). MgAl LDH was synthesized ...
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In this report, we have explored the thermal stability and flammability of unsaturated polyester resin (UP) nano-composites blended with flame retardant trixylenyl phosphate (TXP) and nano-filler dodecyl sulphate intercalated magnesium aluminum layered double hydroxide (MgAlDS LDH). MgAl LDH was synthesized by co-precipitation method and anion dodecyl sulphate was intercalated by ion exchange method. The XRD analysis denoted the presence of layered double hydroxide crystal lattice which supports the structural conformation. The IR spectra of trixylenyl phosphate (TXP), MgAl LDH and MgAlDS LDH depicted their relevant vibrational transitions. The nano-composites of unsaturated polyester, crossed linked with styrene, were prepared by mixing varying proportions of TXP and MgAlDS LDH. The XRD of the composites reveal the exfoliation of MgAlDS LDH in polymer matrix, which enhances the thermal stability of nano-composite containing 1% MgAlDS LDH along with TXP than the polymer containing TXP alone, was shown by TGA. The Unsaturated polyester (UP) resin nano-composite decomposes by two stages. There was 8% reduction in peak mass loss rate of nano-composite containing 1% MgAlDS LDH along with TXP in comparison to nano-composite containing only TXP. UL-94 study shows that MgAlDS LDH had flame retardant properties as confirmed by reduction of burning rate in comparison to virgin unsaturated polyester resin. Morphology analysis by SEM on Charred residue of nanocomposite containing 23% TXP and 1% MgAlDS LDH has shown more compact, hard and without any pin holes upper layer than nanocomposite containing only 24% TXP alone. This can be used in preparation of flame retardant articles of unsaturated polyester resin and will allow use of unsaturated polyester on places where it is avoided due to high flammability and low thermal stability. Copyright © 2017 VBRI Press.
