Malatesh S. Pujar; Shirajahammad M. Hunagund; Vani R. Desai; Ashok H. Sidarai
Abstract
Herein, we synthesis ZnO nanosheets via facial hydrothermal method using sodium hydroxide (NaOH) as a stabilizer. The synthesized ZnO was subjected to various characterizations for analysis of their optical, structural, functional groups, chemical composition, surface morphological and thermal studies, ...
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Herein, we synthesis ZnO nanosheets via facial hydrothermal method using sodium hydroxide (NaOH) as a stabilizer. The synthesized ZnO was subjected to various characterizations for analysis of their optical, structural, functional groups, chemical composition, surface morphological and thermal studies, obtained results reveals the following features; UV-Vis spectroscopy analysis shows absorption maximum at 272 nm which confirms the preliminary presence of ZnO material. X-ray diffraction (XRD) analysis reveals the average crystalline grain size is found to be of around 38.10 nm. Fourier transform infrared spectroscopy (FT-IR) analysis reveals the presence of O-H, C-H, C-N and Zn-O bands. Atomic force microscopy (AFM) and scanning electron microscopy analysis (SEM) shows the topological structure of ZnO and it having nanosheets like nature. Energy dispersive X-ray spectroscopy (EDS) analysis confirms the chemical compositions were Zn and O elements. Further, we observed by thermo gravimetric analysis (TGA) that for synthesized ZnO nanosheets weight loss is of 15.574% was occurred at 47.49˚ C to 300˚ C. After 300˚C, none of the materials underwent greater than 1% of weight loss. From DSC analysis, we observed that there are endothermic reactions in between 23˚C to 500˚C. In addition, we proposed to study biological activities of these synthesized ZnO nanosheets. Copyright © 2018 VBRI Press
Damyanti G Badagha; C D Modhera
Abstract
Now days, Nanotechnology is introduced in civil industry for ceramics, composites, and mortar to achieve better performance in different mechanical parameters of these materials. At the same time, Environment prevention is pin point for the civil industry because of cement production. As a solution of ...
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Now days, Nanotechnology is introduced in civil industry for ceramics, composites, and mortar to achieve better performance in different mechanical parameters of these materials. At the same time, Environment prevention is pin point for the civil industry because of cement production. As a solution of better performance of structural materials with environment prevention, steel making industry waste powder at Nano-scale giving better enhanced strength of mortar. This research work introducing the acceptable partial replacement of the steel waste powder in place of ordinary Portland cement to minimize environmental pollution due to cement production considering waste disposal solution. In the mortar making process, pure steel making waste used in powder form having compositions of SiO2, Al2O3, Fe2O3, CaO, MgO, SO3, Sulphide, Na2O3, K2O, Cl and MnO. Combined effect of these all compositions greatly affected on the mechanical properties of mortar containing this waste powder. To know the effect of this waste powder containing all these compositions in mortar, different mechanical parameters of mortar like compression, tension, flexural, shear and impact test were performed. For this innovative approach, steel making industry waste powder was examined to set consistency for mortar making purpose. To get optimum dosage of waste powder, 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% replacement were done in place of cement. Physical parameters like Compressive, Tensile and Flexural, Shear and Impact strength were examined using optimum dosage of waste powder. This innovative research work introduced the enhanced strength after 3 days, 7 days and 28 days curing. From this research work, it is advisable to use mortar containing waste powder in load bearing structures which is giving sustainable waste disposal solution including CO2 reduction in environment. Copyright © 2018 VBRI Press.
Sitakshi Gupta; Chhaya Ravikant
Abstract
Nowadays, gas sensors are fast becoming an imperative part of modern life with extensive applications in domestic safety, environmental monitoring, industrial process control, public security, medical applications and chemical warfare assessment amongst many others. The detection of minor gas leaks has ...
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Nowadays, gas sensors are fast becoming an imperative part of modern life with extensive applications in domestic safety, environmental monitoring, industrial process control, public security, medical applications and chemical warfare assessment amongst many others. The detection of minor gas leaks has been a challenging area of research, particularly in view of the hazards to human health and safety posed by toxic gases like NO2, NO, CO, NH3 etc and combustible gases like methane, hydrogen gas and some volatile organic compounds. Thus it is imperative to evolve and employ simple yet reliable gas sensing mechanisms with optimum response and selectivity towards even low concentration of analyte gas at room temperature. Most of the conventional gas sensors are based on metal-oxide semiconductors which are low-cost, exhibit good sensitivity and fast response/recovery. Zinc oxide is one such n-type semiconducting oxide, which has been widely studied for gas sensing response due to its ease of fabrication, high sensitivity and environment-friendly nature. However, the operating temperature of such sensors is usually high (>200°C) owing to the wide band-gap (3.37 eV) and high electrical resistance (kΩ-MΩ), which limits their practical utilization. In order to be used in hazard monitoring and home/workplace safety, the gas sensors need to be sensitive to gas exposure in mild operating conditions. As an alternative, more recently, graphene and its derivatives like pristine graphene (PG), reduced graphene oxide (rGO) etc. have been studied for sensing applications owing to their exceptional electronic and physical properties such as high carrier mobility at room temperature, good thermal stability, high mechanical strength, ballistic conductivity and large specific surface area. These sensors show high sensitivity at low operating temperatures (down to room temperature) towards low concentrations of analyte gas. However most of these rGO based sensors exhibit relatively longer response/recovery times than metal-oxide based gas sensors. Hence, nanocomposites formed by hybridizing graphene or its derivatives with metal-oxide nanoparticles are being explored as gas sensing materials. Combining reduced graphene oxide with zinc oxide to form hybrid nanostructures is particularly interesting because not only do they display the individual properties of the metal oxide NPs (faster response/recovery times) and of graphene (high electronic conductivity leading to efficient room temperature gas response), but may also have synergistic effects leading to better sensitivity as a gas sensing material. Here we present a review of the recent progress in rGO-ZnO nanocomposites based gas sensors. Copyright © 2018 VBRI Press.
Nilanjal Misra; Virendra Kumar; Swarnima Rawat; Narender Kumar Goel; Shubhangi A. Shelkar; Lalit Varshney
Abstract
A facile, green radiolytic route is described for the synthesis of poly (2,3-Epoxypropylmethacrylate) (PEPMA) stabilized Gold nanoparticles (PEPMA-Au-NPs) via gamma radiolytic reduction of an aqueous solution of HAuCl4 precursor ions containing EPMA as a stabilizing/capping agent. The effect of different ...
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A facile, green radiolytic route is described for the synthesis of poly (2,3-Epoxypropylmethacrylate) (PEPMA) stabilized Gold nanoparticles (PEPMA-Au-NPs) via gamma radiolytic reduction of an aqueous solution of HAuCl4 precursor ions containing EPMA as a stabilizing/capping agent. The effect of different experimental parameters, such as precursor ions and stabilizing agent concentration, gamma radiation dose and solvent polarity on the properties of Au-NPs were studied. PEPMA-Au-NPs system was characterized by UV-visible spectroscopy, TEM and particle size analysis techniques. PEPMA-Au-NPs showed characteristic Localized Surface Plasmon Resonance (LSPR) band at ~530nm. TEM analysis confirmed the formation of spherical particles with an average size of 7.6nm±3.1nm. PEPMA-Au NPs prepared under optimized conditions were employed as an efficient catalytic system to carry out the reduction of p-nitrophenol (PNP) to p-aminophenol (PAP). The reaction was observed to follow pseudo first order kinetics and demonstrated good efficiency in carrying out the catalytic reduction reaction under optimized conditions. Copyright © 2018 VBRI Press.
Mrinmoy Garai; Basudeb Karmakar
Abstract
This study exemplifies the effects of 5 wt.% Pb2+ addition replacing the same Zn2+ content on crystallization and microstructure of 10B2O3-16Al2O3-39SiO2-12MgO-12MgF2-4K2O-1Li2O-1AlPO4 (wt.%) glass-ceramic composite. Increase of linear thermal-expansion (6.93 to 7.18×10-6/K at 50-600°C) in ...
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This study exemplifies the effects of 5 wt.% Pb2+ addition replacing the same Zn2+ content on crystallization and microstructure of 10B2O3-16Al2O3-39SiO2-12MgO-12MgF2-4K2O-1Li2O-1AlPO4 (wt.%) glass-ceramic composite. Increase of linear thermal-expansion (6.93 to 7.18×10-6/K at 50-600°C) in substituting Zn2+ by Pb2+ is attributed to the field-strength of cations. Opaque crystalline glass-ceramics are derived from the transparent glasses (synthesized by single-step melt-quenching at 1500OC) by controlled heat-treatment at 1050°C and the predominant crystalline-phase was identified as fluorophlogopite mica, KMg3AlSi3O10F2. FFESEM of the ZnO containing glass-ceramics revealed that 100-200 µm sized plate-like crystals are in ‘well-packed interlocked arrangement’; which changed to ‘nanocrystalline microstructure’ combined of ‘spherical droplet like’ nanocrystals (crystal size = 10-50 nm) in attendance of PbO. Decrease in linear thermal-expansion (11.03 to 7.93 × 10-6/K at 50-700°C) due to the substitution of ZnO is ascribed to the crystallization inhibiting tendency of PbO towards boroaluminosilicate system. Thermal-expansion of ZnO containing glass-ceramic is large (> 11 × 10-6/K at 50-700 and 50-800°C) which can exhibit their enough thermal shock resistivity to be suitable for high-temperature sealing application. Copyright © 2017 VBRI Press.
Mahlatse F. Manamela; Thuto E. Mosuang; Bonex W. Mwakikunga
Abstract
The mechano-chemical technique was employed to synthesise cobalt and indium single and double doped as well as the undoped ZnO nanopowder samples. The X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) results confirm that the prepared samples were of hexagonal wurzite form. A new peak ...
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The mechano-chemical technique was employed to synthesise cobalt and indium single and double doped as well as the undoped ZnO nanopowder samples. The X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) results confirm that the prepared samples were of hexagonal wurzite form. A new peak was observed in the diffraction pattern of the In doped ZnO nanopowders. Doping the ZnO nanoparticles with Co and In did not significantly affect the lattice parameters, even though the average grain sizes were found to be reduced. The morphology of the samples revealed by the scanning electron microscopy (SEM) images appear to be more spherical. The excitation wavelength of 350 nm was used in the photoluminescence (PL) study where various defects related emissions were observed for the doped and undoped ZnO nanoparticles. The energy band gap of the prepared samples was calculated from the ultraviolet-visible spectroscopy (UV-Vis) data. It was found that the doped ZnO nanoparticles had smaller energy band gap compared to the undoped ZnO nanoparticles. The Raman experiment were performed at the excitation wavelength of 514.532 nm and E2 (high) mode had the most intense peak. Copyright © 2018 VBRI Press.
Subhash Nimanpure; S. A. R. Hashmi; Rajnish Kumar; Archana Nigrawal; H.N. Bhargaw; Ajay Naik
Abstract
Environment friendly electrical insulation material was developed using bio based rectangular cross sectioned sisal fibrils as reinforcement. High content cellulose base fibrils fibrillated by mechanical disintegration method into macro and micro fibrils from coarse sisal fibre. This fibrils were randomly ...
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Environment friendly electrical insulation material was developed using bio based rectangular cross sectioned sisal fibrils as reinforcement. High content cellulose base fibrils fibrillated by mechanical disintegration method into macro and micro fibrils from coarse sisal fibre. This fibrils were randomly distributed in polymer matrix. These composites were characterized in term of electrical, mechanical and thermal properties to investigate the stability for high strength electrical insulation materials. Excellent mechanical properties were observed. Tensile, flexural and impact strength of composites at 40 wt. % fibril loading improved by 151.34, 197.43 and 360.07 % as compared to unsaturated polyester resin. A few micro-mechanical models were compared with the experimental values. Nielson-Chen Model predicted the experimental data most accurately. The electrical properties of surface modified sisal fibril composites improved significantly in higher frequency. DSC analysis showed that the decomposition temperature of composite was higher, around 22°C than that of the polyester resin. Thermal degradation reduced and was observed in the range of 83-87% of fibril composites as compared to 97% of resin. Fibril composites are highly sensitive to electrical frequency and exhibit excellent electrical insulation property at 20 kHz. Alkali treated fibril based composites resulted an environment friendly thermally stable, high strength insulation material. Copyright © 2018 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
Sultan A. Al-horaibi; S.T. Gaikwad; Anjali S . Rajbhoj
Abstract
The requirement for energy is ever increasing in the past few years due to the need for the innovation of clean energy and eco-friendly technologies. Symmetric and asymmetric SQ-dyes have received increasing attention and great potential for use as SQ-sensitizers for application in dye sensitized solar ...
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The requirement for energy is ever increasing in the past few years due to the need for the innovation of clean energy and eco-friendly technologies. Symmetric and asymmetric SQ-dyes have received increasing attention and great potential for use as SQ-sensitizers for application in dye sensitized solar cells (DSSC).This review article gives a synopsis of the advancements on SQ-sensitizers in the domain of DSSC and the chance used to enhance their overall energy conversion efficiency. Specifically, the primary factors in charge of the low values of open-circuit voltage (Voc) short-circuit photocurrent (Jsc) and fill factor (FF) are debated in detail. Future orientations in research and expanded absorptions of near-infrared region (NIR) by development organic substances and their applications are suggested from a personal point of view. Copyright © 2018 VBRI Press.
Subhashree Patra; Pinaki Chatterjee; Kamal L. Mohanta; Chhatrapati Parida
Abstract
Modification of surface of natural fiber by gamma irradiation is an effective and economical technique and of viable interests in the terrain of biocomposites. The response of doses (0.5 Gy,1Gy and 2 Gy) of gamma irradiation of 6MV energy on the structural, tensile and flexural ...
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Modification of surface of natural fiber by gamma irradiation is an effective and economical technique and of viable interests in the terrain of biocomposites. The response of doses (0.5 Gy,1Gy and 2 Gy) of gamma irradiation of 6MV energy on the structural, tensile and flexural properties of composites using poly lactic acid (PLA) and fibers of luffa cylindrical (LC) is studied. Preliminary results suggests promising mechanical properties. After reinforcement of irradiated LC fiber, the tensile strength and flexural strength of the virgin PLA matrix increases by 60% and 155% respectively. The E-modulus of the composites are also heightened with addition of irradiated fiber up to the limit of 1 Gy of irradiation dose and then decreases with higher dose of irradiation. Furthermore the tensile strength and flexural strength of the composites increases with incorporation of very low content of LC fiber up to 2wt% and decreases with higher loading of fibers (5wt% and 10wt%). Modulus of composites is enhanced with increase in wt of fiber content in the composites. Moreover beefore reinforcement the LC fibers are modified with Ca salts in order to explore the use of these composites in biomedical territory. Copyright © 2018 VBRI Press.
Ketan Jagtap; Raju Pawade
Abstract
Biomanufacturing integrates life science and engineering fundamentals to produce biocompatible products improving the pre-eminence of living. Face turning is an important process used for producing the higher accuracy on metal implants especially on sliding parts. In this experiment effect of depth of ...
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Biomanufacturing integrates life science and engineering fundamentals to produce biocompatible products improving the pre-eminence of living. Face turning is an important process used for producing the higher accuracy on metal implants especially on sliding parts. In this experiment effect of depth of cut, feed rate and cutting speeds are considered on machined Co-Cr-Mo bio-implant alloy by application of RSM. The offline and online measured surface roughness (Ra) and cutting force (Fc) were considered respectively as response variables for investigations. The experimental result shows that depth of cut and feed rate are having predominating effect on measured surface roughness and cutting force respectively. Therefore, the developed models can be efficiently used to predict the surface roughness and cutting force on the machinability of Co-Cr-Mo alloy within 95% confidence intervals ranges of measured parameters. For checking the adequacy of model a confirmation test has been conducted. The optimized parameters can be useful for industrial developments in surface generation for bio-implants. Copyright © 2018 VBRI Press.
Research Article
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.
