Ashok B. Gadkari; Tukaram J. Shinde; Appaso A. Wali; Pramod N. Vasambekar
Abstract
Nanocrystallite ferrites samples with general formula Mg1-xCdx Fe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) were prepared by oxalate co-precipitation method from high purity sulphates. The samples were characterized by XRD, SEM and FT-IR techniques. The phase identification of powder reveals single phase cubic ...
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Nanocrystallite ferrites samples with general formula Mg1-xCdx Fe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) were prepared by oxalate co-precipitation method from high purity sulphates. The samples were characterized by XRD, SEM and FT-IR techniques. The phase identification of powder reveals single phase cubic spinel nature of materials. The gas sensing properties were studied for ethanol (C2H5OH), liquid petroleum gas (LPG) and chlorine (Cl2). The MgFe2O4 is sensitive to LPG (~ 80%) followed by Cl2 (~75%) and less to ethanol (~ 58%) at an operating temperature of 225oC. The sample with x = 0.4 has highest sensitivity at operating temperature 225oC for LPG (~ 78%). It shows good sensitivity at operating temperature at 198oC for Cl2 (~75%) and ethanol (~ 65%). The CdFe2O4 sensor (x=1) exhibits very high sensitivity (85%) and good selectivity to ethanol than other tested gases such as LPG (~ 35%) and Cl2 (~ 30%). The response and recovery time decreases with increase in Cd2+ content for LPG, Cl2 and ethanol. The shorter response is observed to CdFe2O4 for LPG, Cl2 and ethanol.
Raj K. Gupta; Ajit K. Mahapatro; Ram P. Tandon
Abstract
This work demonstrates the achievement of high thermopower in the pellets of calcium cobalt oxide (Ca3Co4O9) co-doped with aluminium (Al) and titanium (Ti). The pellets of Ca(3-x)AlxCo(4-y)TiyO9+δ with x, y = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5, oxide ceramics are prepared using a hot-press machine ...
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This work demonstrates the achievement of high thermopower in the pellets of calcium cobalt oxide (Ca3Co4O9) co-doped with aluminium (Al) and titanium (Ti). The pellets of Ca(3-x)AlxCo(4-y)TiyO9+δ with x, y = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5, oxide ceramics are prepared using a hot-press machine by applying an uniaxial pressure of 70 MPa at a dwell temperature of850 ºC. Microstructure imaging reveals compactness of good connectivity among grains with the estimated density using Archimedes principle suggests the formation of near perfect (99%) relative density for the new pelleted ceramics. All theco-doped samples exhibit lower electrical resistivity (r) values compared to pure Ca3Co4O9. The maximum Seebeck coefficient (S) of 177 μV/K at 750 K is achieved for the pure Ca3Co4O9 sample. A significant improvement of 18% in the power factor (S2/r) is realized at 750 K in the co-doped samples containing 0.2 mol% of Al and Ti co-doping. The demonstration of significant thermoelectric properties of Ca(3-x)AlxCo(4-y)TiyO9+δ suggest that these materials could be utilized as promising active material in thermoelectrics. Copyright © 2018 VBRI Press.
Monika Tandon; Pratima Chauhan
Abstract
ZnO-CdS nanocomposite material has been synthesized by Chemical Co-precipitation method. The prepared nanocomposite material has been characterized by UV-visible (UV-vis) spectrophotometer and X-ray diffractometer (XRD). The optical band gap of prepared material lies between 3.6 eV to 4.0 eV. The synthesized ...
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ZnO-CdS nanocomposite material has been synthesized by Chemical Co-precipitation method. The prepared nanocomposite material has been characterized by UV-visible (UV-vis) spectrophotometer and X-ray diffractometer (XRD). The optical band gap of prepared material lies between 3.6 eV to 4.0 eV. The synthesized nanocomposite material has been annealed at two different temperatures 160o C and 200o C. The results of UV-visible characteristic and XRD analysis show that the optical and structural property of the material depends on the temperature at which it has been annealed. A natural dye from beet root extract has been synthesized and has absorbance in visible region. The synthesized nanocomposite material is deposited over the glass plate using spin coater. The thin film of synthesized ZnO-CdS nanocomposite when annealed at higher temperature absorbs more dye than the film annealed at lower temperature. Copyright © 2017 VBRI Press.
Rozalin Panda; Ramakanta Naik; Udai. P. Singh; Naresh. C. Mishra
Abstract
In the present work, Ag/In/Ag/In multilayers were deposited on glass substrates by DC magnetron sputtering and the films were selenized at 350℃. The selenized films were annealed at 450℃ and 500℃. The selenized and annealed films were characterized by X-ray diffraction (XRD), UV-Visible-NIR spectroscopy ...
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In the present work, Ag/In/Ag/In multilayers were deposited on glass substrates by DC magnetron sputtering and the films were selenized at 350℃. The selenized films were annealed at 450℃ and 500℃. The selenized and annealed films were characterized by X-ray diffraction (XRD), UV-Visible-NIR spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). XRD revealed formation of the desired AgInSe2 phase along with Ag2Se as impurity phase. Unlike in previous studies, where conventional approach of optimizing the volume fraction of initial precursor material is adopted to control the phase purity of AgInSe2, we show that annealing highly impure films at 500℃ can suppress the impurity phase and lead to pure AgInSe2 phase. The suppression of the low band gap Ag2Se impurity phase on annealing the films at 500℃ led to increase in the optical band gap. Copyright © 2016 VBRI Press
D.S. Jayalakshmi; M. Nasreen Banu; M. Sundareswari; D. Hemanand; E. Viswanathan
Abstract
The structural, bonding, magnetic, electronic, elastic and thermoelectric nature of superconducting material namely MgB2, with hexagonal structure (space group is 191) are studied by first principle calculation. The optimized lattice parameters of MgB2 are a=b=3.084289 Ǻ and c= 3.51527 Ǻ ...
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The structural, bonding, magnetic, electronic, elastic and thermoelectric nature of superconducting material namely MgB2, with hexagonal structure (space group is 191) are studied by first principle calculation. The optimized lattice parameters of MgB2 are a=b=3.084289 Ǻ and c= 3.51527 Ǻ and the electron phonon coupling constant (λ), Debye temperature, critical temperature, Seebeck coefficient, electrical resistivity and the elastic constants (C11, C12, C13, C33, C55) are calculated and agreed well with available outcome. To predict other possible superconducting materials belong to MgB2 family, Mg is further doped with transition element Titanium (Ti) and analyzed. Copyright © VBRI Press.
M. Shanmuga Sundaram; V. Vijayalakshmi; P. Dhanasekaran; O.N. Balasundaram; S. Palaniswamy
Abstract
Current work, L-alanine single crystals in the presence of potassium nitrate were grown by slow evaporation method. The unit cell parameters and crystalline structure of the L-alanine crystal were analysed using powder XRD (PXRD) technique. The numerous functional groups and vibrational modes of the ...
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Current work, L-alanine single crystals in the presence of potassium nitrate were grown by slow evaporation method. The unit cell parameters and crystalline structure of the L-alanine crystal were analysed using powder XRD (PXRD) technique. The numerous functional groups and vibrational modes of the grown crystal were identified by FTIR analysis. The linear optical analysis has been employed in the wavelength range 200-2500 nm to find out the optical transparency of the grown crystal. Nonlinear optical efficiency of the grown crystal is 1.12 times superior to the reference crystalline material KDP. The negative photoconductivity of the grown crystal was exposed by photoconductivity analysis. Copyright © 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.
Akanksha Prakash; Shailesh Narain Sharma
Abstract
Indium Phosphide quantum dots (InP QDs) having various applications can be used for both LEDs and photovoltaics owing to its highly luminescent properties and energy harvesting potential respectively. In our work we have synthesized InP QDs using hot injection technique. Further post synthesis treatment ...
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Indium Phosphide quantum dots (InP QDs) having various applications can be used for both LEDs and photovoltaics owing to its highly luminescent properties and energy harvesting potential respectively. In our work we have synthesized InP QDs using hot injection technique. Further post synthesis treatment was given and InP/ZnS core shell nanocrystals were grown on InP core. Composites with P3HT conducting polymer were made in order to study the charge transfer/energy transfer phenomenon. InP and InP/ZnS QDs show an effective phenomenon of energy transfer and PL increment is observed in the case of composites. Whereas in the case of treated InP QDs a decrement in the PL was observed. Treatment results in removal of the surface defects and traps which help in effective charge transfer rather than energy transfer. Post synthesis treatment increases the monodispersity of the QDs which results in high quality QDs without any defects. With a simple post synthesis treatment,InP QDs can be used for both LEDs as well as photovoltaic applications. The future work involves the device fabrication of InP QDs and treated InP QDs for LED and solar cells respectively. Various characterization such photoluminescence, transmission electron microscopy, selected area diffraction was done in order to confirm the charge/energy transfer phenomenon. Copyright © 2016 VBRI Press.
Poonam R. Kharangarh; Akshay Kumar; Raj K. Sharma; Gurmeet Singh
Abstract
With an objective to develop electrode materials with high specific capacitance and good stability, we prepared Graphene quantum dot-doped with transition metal of HCl by using a facile hydrothermal at different temperatures (~ 800C- 1400C). Samples were characterized by Raman spectroscopy, Powdered ...
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With an objective to develop electrode materials with high specific capacitance and good stability, we prepared Graphene quantum dot-doped with transition metal of HCl by using a facile hydrothermal at different temperatures (~ 800C- 1400C). Samples were characterized by Raman spectroscopy, Powdered X-ray Diffraction (PXRD), U-V Visible Spectroscopy, and Transmission Electron Spectroscopy (TEM). Raman spectroscopy study reveals intensity ratio alters with changes in temperatures. It was found the variation in size with doped GQDs under different temperature conditions from TEM measurements. The observed blue shifts in the energy gap of HCl doped GQDs at higher temperature are attributed to the strong interaction of GQDs with HCl. Electrochemical studies showed a superior strategy for generating transition metals doped GQDs. The higher electrochemical activity has been originated by using cyclic voltammetry of HCl doped GQDs at 1200C and is found to be superior electrodes than all other heated samples. The simplicity of synthesized material suggests electrode to understand the charge storage mechanism for commercial applications. Copyright © 2017 VBRI Press.
Sandip Maiti; Sumanta Kumar Karan; Jin Kon Kim; Bhanu Bhusan Khatua
Abstract
Today, we stand at the edge of exploring carbon nanotube (CNT) and graphene based polymer composites and supercapacitors as next generation multifunctional materials. Supercapacitor materials have been alternative energy source in modern electronics era. Due to their excellent electrical, mechanical ...
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Today, we stand at the edge of exploring carbon nanotube (CNT) and graphene based polymer composites and supercapacitors as next generation multifunctional materials. Supercapacitor materials have been alternative energy source in modern electronics era. Due to their excellent electrical, mechanical and thermal properties, CNTs, graphene and their derivatives have been most promising nanofillers in different fieldsof applications. Inthis review, we have focused electrical conductivity of the polymer composites as well as supercapacitor behavior of composites based on CNTs, graphene and their derivatives. To enhance the electrical and supercapacitor properties of the composites, nanofillers are functionalized or chemically modified through different techniques. Here, we have discussed the structure, preparation,electrical and supercapacitor properties of different composites based on CNTs, graphene and their derivatives along with detailed reported scientific literature.Copyright © 2018VBRI Press
Richa Sharma; N. C. Mehra; R. P. Tandon
Abstract
In the present work, the composite series (1-x) Ba0.94Ca0.06TiO3 - (x) Ni0.7Co0.1Zn0.2Fe2O4 (where x = 0.1, 0.2, 0.3 and 0.4 wt. fraction) was synthesized by solid state reaction method followed by conventional sintering. The structure and morphology of prepared samples were examined using X-ray diffractometer ...
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In the present work, the composite series (1-x) Ba0.94Ca0.06TiO3 - (x) Ni0.7Co0.1Zn0.2Fe2O4 (where x = 0.1, 0.2, 0.3 and 0.4 wt. fraction) was synthesized by solid state reaction method followed by conventional sintering. The structure and morphology of prepared samples were examined using X-ray diffractometer (XRD) and scanning electron microscopy (SEM), respectively. In addition, dielectric constant (ε΄) and loss tangent (tan δ) of prepared samples were measured as a function of frequency and temperature. The room temperature values of dielectric constant (ε΄) of composite samples are found to decrease from 529.29 to 159.52 as ferrite content increased from x = 0.1 to x = 0.4 at 1 kHz frequency. Moreover, in the dielectric constant vs. temperature plots of the composite samples, ferroelectric to paraelectric phase transition of pure Ba0.94Ca0.06TiO3 is observed. Furthermore, ferroelectric and magnetic properties of the composite samples were studied at room temperature. With increasing addition of the ferrite content in the composites, the ferroelectric properties get weakened and the magnetic behavior of the composite samples improved. The maximum values of saturation magnetization ( ) and remanant magnetization ( ) are 22.52 emu/gm and 3.39 emu/gm, respectively, for composite sample containing 0.4 wt. fraction Ni0.7Co0.1Zn0.2Fe2O4. Copyright © 2017 VBRI Press.
Ishwar Naik; Rajashekhar Bhajantri; Sunil Rathod; Jagadish Naik
Abstract
In the present work, spin coated thin films of P3HT: NTCDA donor- acceptor blends of weight ratios 3:1, 1:1 ,1:3 are prepared in Toluene using the self-made spin coating machine. The experiment is focused to optimize the P:N weight ratio of the photoactive blend that can absorb maximum solar energy and ...
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In the present work, spin coated thin films of P3HT: NTCDA donor- acceptor blends of weight ratios 3:1, 1:1 ,1:3 are prepared in Toluene using the self-made spin coating machine. The experiment is focused to optimize the P:N weight ratio of the photoactive blend that can absorb maximum solar energy and also to enhance the absorption by doping it with gold nano particles. Absorption property of the samples are studied using JASCO UV VIS 670 spectrometer which shows that 1:3 blend has the broad spectral response and considered to be the best active blend. The optical band gaps of the samples are determined through Tauc’s plot, wherein the onset wavelength for 1:3 sample is found to be 660nm with a band gap of 1.87 eV. The optimized 1:3 blend is doped with gold nano-particle dispersion in citrate buffer. The absorbance gets increased on doping with nano particle with extremely broadened spectral response which is attributed to the Localized Surface Plasmon Resonance(LSPR). Photons are trapped by the gold particles in the polymer matrix for the efficient harvesting of the solar energy. The construction of the solar cell using this Plasmon enhanced photoactive material is the work under progress. Copyright © 2017 VBRI Press.
Elena Brandaleze; Mykhaylo Romanyuk; Martina Avalos
Abstract
The alloy design concepts of high performance steels, involve the knowledge on the stability of carbides associated with nanoscale phenomena present in the structure as result of the deformation suffered during the thermomechanical processes. The understanding of the nanoscale phenomena open new frontiers ...
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The alloy design concepts of high performance steels, involve the knowledge on the stability of carbides associated with nanoscale phenomena present in the structure as result of the deformation suffered during the thermomechanical processes. The understanding of the nanoscale phenomena open new frontiers to understand mechanical behaviours in the steel, not totally clarified until now. The paper discuss the structure evolution during wire drawing of pearlitic steels and the impact of cementite stability on different nanoscale structure phenomena, which explain the specific mechanical behaviour to achieve ultra-high strength. Results on the kinetic and stability of carbides predicted on the base of thermodynamic simulation are correlated with thermal analysis tests results (dilatometry and differential scanning calorimetry) carried out by different authors in order to understand the cementite (Fe3C) dissolution during plastic deformation. In addition, information obtained by traditional and no traditional microscopy techniques and X ray diffraction complete the study and allows to understand more deeply the structure evolution, including nanoscale phenomena that justify the mechanical behaviour during wiredrawing and the final strength level. The dislocation substructure evolution together with the cementite dissolution during sever plastic deformation which leads to a steadily increase of the strain hardening is clarified. Copyright © 2018 VBRI Press.
Himanshi Jauhari; Rakhi Grover; Omita Nanda; Kanchan Saxena
Abstract
Dye Sensitized Solar Cells (DSSCs) present a significant renewable energy source in terms of control of different parameters governing flexibility, efficiency, lifetime and cost. The liquid electrolytes used inside the cells are generally responsible for the leakage and inefficient encapsulation related ...
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Dye Sensitized Solar Cells (DSSCs) present a significant renewable energy source in terms of control of different parameters governing flexibility, efficiency, lifetime and cost. The liquid electrolytes used inside the cells are generally responsible for the leakage and inefficient encapsulation related issues. These are critical for practical applications of DSSCs. The choice of electrolyte medium used in the cell should take into account the fast regeneration of electrolyte and redox potential of the dye. Organic dyes in general, exhibit better extinction coefficients and variant color ranges. The present work is focused on quasi solid state DSSCs based on an organic dye. For the fabrication of devices, nanocrystalline titanium-di-oxide (TiO2) films were used as the photoanode and well known organic dye Eosin B as the sensitizer. The photovoltaic performance of the cells was measured at different light intensities. The results exhibited the quantum efficiency of organic dye Eosin B which can be used as a potential sensitizer in conjugation with quasi solid state electrolytes. Copyright © 2017 VBRI Press.
Alejandro Zuleta; Andrés Valencia-Escobar; Carlos Rodríguez
Abstract
The high requirements of Bicycle Motocross (BMX) race conditions demands on the bicycle frame complex dynamic and static loads states by which it is expected that frames to experience high levels of stress and strain. To build efficient bike frames in terms of performance, weight and quality, it is necessary ...
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The high requirements of Bicycle Motocross (BMX) race conditions demands on the bicycle frame complex dynamic and static loads states by which it is expected that frames to experience high levels of stress and strain. To build efficient bike frames in terms of performance, weight and quality, it is necessary to analyse systematically its response against different loads. The aim of this work is to perform the design of a BMX frame for the national team of Colombia, including the microstructural and mechanical characterization of the initial bicycle frame as complement for the macrostructural characterization of the frame in static conditions. The components of the bike frame were exanimated using optical emission spectrometry, metallographic examinations, microhardness measurements and mechanical tests. It was found that significant differences of the grain sizes of the samples were reflected in the deformation values measured in the frame showing a high structural anisotropy. Despite this, the microhardness and mechanical resistance values the results show coherence between them. In Addition, safety coefficient of the four of the components of the bicycle frame was calculated finding that coefficient values was the calculated safe factor was 4.27. Copyright © 2018 VBRI Press
Bharti Sharma; Nahar Singh; Ram P. Tandon; Ajit K. Mahapatro
Abstract
This work demonstrates the structural interaction of the as-synthesized zinc peroxide (ZnO2) nanoparticles with fibroblast cells (FBC). The ZnO2 nanoparticles (ZNP) of desired sizes (10-20 nm) are synthesized, and the purity and structural confirmations are studied using various imaging and spectroscopic ...
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This work demonstrates the structural interaction of the as-synthesized zinc peroxide (ZnO2) nanoparticles with fibroblast cells (FBC). The ZnO2 nanoparticles (ZNP) of desired sizes (10-20 nm) are synthesized, and the purity and structural confirmations are studied using various imaging and spectroscopic techniques. FBC (buffalo) lines are cultured in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum and penicillin (100 µg/mL), and with non-essential amino acid and vitamin as additional ingredients, followed by incubation at 37°C with continuous purging of the chamber using 5% CO2. The fluorescent microscopic images are captured for the initial healthy and cultured FBCs, and after pouring the nanoparticles in the cultured FBCs. Healthy cell-growth is noticed during the cell culture process suggesting the formation of ZNP-FBC complexes without contamination and coagulation. After allowing the interaction of ZNPs with the FBCs, the presence of ZNPs only on the cell sites are observed without coagulation of ZNPs in the cell areas, suggesting the selective interference of ZNPs on the surface of the grown cell. The understanding of the interaction process of the ZNPs with the living cell, would provide the practical utilization of the ZNPs in nanomedicine and nano-drug delivery. Copyright © 2017 VBRI Press.
Kalawati Saini; Florence Jojeph; Smriti S. Bhatia
Abstract
The copper (II) extended metal organic frameworks with oxalic acid ( ox = oxalate ) [Na 2 ( Cu ( ox) 2 ].H2O and[ (NH4)2 ({ Cu ( ox)2(H2O)2}{ Cu( ox)2 }] .H2O have been synthesized using electrochemical route at room temperature and applied potential at 12.5 V. Herein copper rod ...
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The copper (II) extended metal organic frameworks with oxalic acid ( ox = oxalate ) [Na 2 ( Cu ( ox) 2 ].H2O and[ (NH4)2 ({ Cu ( ox)2(H2O)2}{ Cu( ox)2 }] .H2O have been synthesized using electrochemical route at room temperature and applied potential at 12.5 V. Herein copper rod has taken as a working electrode and platinum wire as a reference electrode. The single crystal X-ray diffraction (SXRD) and other supportive techniques like as PXRD, TGA/DTA, FT-IR have been used for structural characterizations. Metal organic frameworks (MOFs) are crystalline in nature where the ligands and metal ions are assembled infinitely resulting in one, two or three-dimensional networks having direct metal-ligand coordination. The growth of the solids has been explained corresponding to the mechanistic approach proposed by Ramanan and Whittingham. The crystal packing has been influenced by the supporting electrolyte. The electrolytic method is a simple process, low energy consumption, high yield, easy control and no environmental pollution. Copyright © 2018 VBRI Press
Mine Uslu Uysal
Abstract
Adhesively bonded technique is preferred more than bolted joining technique for glass connections. Glass panels supported by metal frame are generally used to glazing applications. Obtaining the critical buckling temperature is highly important and also thermal buckling behaviour of the glass joints ...
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Adhesively bonded technique is preferred more than bolted joining technique for glass connections. Glass panels supported by metal frame are generally used to glazing applications. Obtaining the critical buckling temperature is highly important and also thermal buckling behaviour of the glass joints should be considered. Stability of the joint is influenced by many design parameters such as types of adhesive/adherent materials. This paper presents a finite element method (FEM) of adhesively bonded scarf joint under thermal loading. Finite element models for the glass joint having isotropic (Aluminum and Steel) or anisotropic (Boron-epoxy, Kevlar-epoxy and E glass-epoxy) adherents were established by ANSYS® commercial program. FEM analysis was based on the usage of special surface to surface contact elements. The effects of adherent properties on the critical buckling temperature were investigated. Adhesively bonded scarf joint mode shapes were presented for the first five modes. Among the anisotropic adherent materials, the highest critical buckling temperature was determined for the boron-epoxy/glass joint. Additionally, the results showed that the adherent materials should be chosen carefully for adhesively bonded glass joints. Copyright © 2017 VBRI Press.
Rohit R. Powar; Ashok B. Gadkari; Pravina B. Piste; Dnyandevo N. Zambare
Abstract
Nanoparticles of Zinc substituted Cobalt ferrite powders having general formula ZnxCo1-xFe2O4 (x = 0, 0.25, 0.5, 0.75, 1.0) have been produced by using analytical grade nitrates and hexadecyltrimethylammonium bromide (CTAB) as structure directing reagent via Chemical co-precipitation method. The structure ...
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Nanoparticles of Zinc substituted Cobalt ferrite powders having general formula ZnxCo1-xFe2O4 (x = 0, 0.25, 0.5, 0.75, 1.0) have been produced by using analytical grade nitrates and hexadecyltrimethylammonium bromide (CTAB) as structure directing reagent via Chemical co-precipitation method. The structure and morphology of prepared polycrystalline ferrite nanoparticles were investigated by X-ray diffraction (XRD), Fourier Transform Infrared Radiation (FTIR) and Scanning electron microscopy (SEM) respectively. Thermogravimetric differential analysis (TG/DTA) technique gives information about ferrite phase formation occurs beyond 450 ºC. The XRD analysis confirms the establishment of the cubic spinel structure with the presence of minor secondary phase of α-Fe2O3 (hematite) at a calcination temperature of 650 ºC. The polycrystalline mixed zinc cobalt ferrite nanoparticles showed a dual phase and crystallite size lies in the range 6-11 nm. FE-SEM microstructure shows the nearly spherical polycrystalline nanoparticles with a particle size in between 0.11-0.20 µm. The FT-IR spectra display two significant strong absorption bands nearby in the range of 400 cm-1 and 600 cm-1 on the tetrahedral and octahedral sites respectively. Copyright © 2018 VBRI Press.
Saji S K; R Radhakrishnan; T Jeyasingh; R Vinodkumar; Shibu M. Eappen; P R Sobhana Wariar
Abstract
perovskite material was prepared by solution combustion technique. XRD results revealed that the material crystallizes in a rhombohedral crystal symmetry with space group Rc. The ac conductivity and dielectric properties of the sintered pellet of the sample have been investigated in the frequency ...
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perovskite material was prepared by solution combustion technique. XRD results revealed that the material crystallizes in a rhombohedral crystal symmetry with space group Rc. The ac conductivity and dielectric properties of the sintered pellet of the sample have been investigated in the frequency range 1Hz to 1MHz for a wide range of temperatures. The experimental results indicate that the ac conductivity (ω), dielectric constant () and dielectric loss ( ) depends on depends on the temperature and frequency. The ac conductivity was found to obey the power law with and the behavior of exponent n with temperature and the value of n suggest ion hopping is the charge transport mechanism in the material. The obtained results are compared to the principal theories that describe the universal dielectric response behavior. The value and were found to be temperature and frequency dependent. Copyright © 2018 VBRI Press.
Bhishma Karki; Jeevan Jyoti Nakarmi; Rhiddi Bir singh; Manish Banerjee
Abstract
The influence of Au doping in ZnO thin films was studied with respect to photoelectrocatalytic degradation of methylene blue (MB). Influence of Au doping concentration onto PEC structural morphological, optical and luminescence properties of the ZnO thin films were thoroughly investigated. The maximum ...
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The influence of Au doping in ZnO thin films was studied with respect to photoelectrocatalytic degradation of methylene blue (MB). Influence of Au doping concentration onto PEC structural morphological, optical and luminescence properties of the ZnO thin films were thoroughly investigated. The maximum value of Isc and Voc for 3 at. % Au:ZnO thin films confirms the optimization of doping percentage. XRD and SEM were used to study the structure and morphology of the films. Films were nanocrystalline and exhibit a hexagonal crystal structure with no additional phases of gold compounds. For degradation of MB, Au:ZnO films were used as photoelectrode, it was observed that due to Au:ZnO 80% degradation of MB occurs in 150 min. Moreover, large area (100 cm2) Au doped ZnO thin films have been prepared on FTO coated glasses (10–15 Ω). Photocorrosion of ZnO electrode was examined by atomic absorption spectroscopy and no zinc was observed in AAS measurement. Copyright © 2017 VBRI Press.
Prabhuodeyara M. Gurubasavaraj; Jasmith S. Charantimath
Abstract
In this work, we report the synthesis, structural characterization of Group 4 mono and bis-hydroxides and their derivatives and their catalytic properties in the Ring Opening Polymerization (ROP) of rac-Lactide. The hydroxides, and their multimetallic assemblies were characterized, using 1H NMR, 2D NMR, ...
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In this work, we report the synthesis, structural characterization of Group 4 mono and bis-hydroxides and their derivatives and their catalytic properties in the Ring Opening Polymerization (ROP) of rac-Lactide. The hydroxides, and their multimetallic assemblies were characterized, using 1H NMR, 2D NMR, Elemental Analysis, and Single crystal XRD. These complexes were used as catalysts for ring opening polymerization of rac-Lactide. All complexes exhibit varied activity in the polymerization but produce heterotactic polylactide in high yield. These polymers were further characterized by 13C NMR.A tendency toward formation of heterotactic polylactide was observed in the bulk polymerizations. Copyright © 2017 VBRI Press.
Mrinal K Adak; Sujoy Chakraborty; Shrabanee Sen; Debasis Dhak
Abstract
Zirconium-aluminium modified iron oxide nano adsorbent was synthesized using chemical route using zirconyl nitrate, aluminium nitrate, ferric nitrate and triethanol amine. The precursor materials were calcined at 900oC for 4 h to obtain a carban free nano-adsorbent. XRD of the calcined powder was ...
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Zirconium-aluminium modified iron oxide nano adsorbent was synthesized using chemical route using zirconyl nitrate, aluminium nitrate, ferric nitrate and triethanol amine. The precursor materials were calcined at 900oC for 4 h to obtain a carban free nano-adsorbent. XRD of the calcined powder was performed to detect the phase and to estimate the crystallite size. Fluoride removal tests were performed using synthesized fluorinated aqueous solutions of 3 ppm, 5 ppm and 10 ppm. The adsorbent dose was considered 15 mints, 30 mints, 45 mints and 60 mints while adsorbent dose were varied from0.1 mg to 0.3 mg for every 100 ml fluorinated aqueous solution. FTIR spectroscopy of the nano-adsorbent was studied before and after fluoride removal. Percentage of fluoride removal was checked for at least three cycles using the same adsorbent. Fluoride concentration of treated aqueous solution was studied using UV-Visible spectrometer using standard zirconium alizarin S solution. Maximum % of fluoride removal was observed up to 99.9% for an adsorbent dose 0.3 mg for a contact time of 15 minutes at 3 ppm fluoride concentration. However, the adsorbent dose for highest % of fluoride removal depends highly on the contact time and initial fluoride concentration and they were found to be very selective. The synthesized nano-sdsorbent could be used commercially for effective fluoride removal from fluorinated water for drinking purpose. Copyright © 2017 VBRI Press.
Andris Berzins; Andris Morozovs; Jan Van den Bulcke; Joris Van Acker
Abstract
Research describes softwood – pine (Pinus sylvestris L.) and spruce (Picea abies [L.] Karst) and hardwood – birch(Betula pendula Roth) binding with inorganic geopolymer binder, the main focus is on the softwood and geopolymerbinding principles. Geopolymer binder is formed from calcined clay ...
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Research describes softwood – pine (Pinus sylvestris L.) and spruce (Picea abies [L.] Karst) and hardwood – birch(Betula pendula Roth) binding with inorganic geopolymer binder, the main focus is on the softwood and geopolymerbinding principles. Geopolymer binder is formed from calcined clay and liquid glass. The research describesgeopolymer binder compositions with various ratios of liquid glass and clay. This research focuses on mechanicalstrength of bonded wood samples in shear test and on visualization of binder in three dimensions using X-ray computed tomography with submicron resolution. The scan results are compared with mechanical strength test results. The resultsof the research shows, that inorganic binder with spruce wood can achieve 7 MPa shear strength. The research describes binding principles that function between wood and geopolymer and explains the main reasons for destruction of joint. Copyright © 2017 VBRI Press.
E. Selvakumar; A. Chandramohan
Abstract
A new organic SHG active salt 3-Nitroanilinium L-tartrate m-nitroaniline (MLM) was synthesized and optically good single crystals were grown by solvent evaporation solution growth method at room temperature. The structure of the crystal identified by single crystal XRD analyses and it belongs to monoclinic ...
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A new organic SHG active salt 3-Nitroanilinium L-tartrate m-nitroaniline (MLM) was synthesized and optically good single crystals were grown by solvent evaporation solution growth method at room temperature. The structure of the crystal identified by single crystal XRD analyses and it belongs to monoclinic crystal system with polar space group P21. The functional groups present in product have been confirmed from the FT-IR spectral study. The optical transmission spectrum was recorded to examine the optical property of the title crystal. The thermo gravimetric and differential thermal analyses were carried out simultaneously to study the thermal behavior of the title crystal. The relative second harmonic generation activity of the title crystal was confirmed by the modified Kurtz-Perry powder test and it was found that the title crystal has 0.5 times second harmonic generation output than that of KDP.
