Editorial
Hisatoshi Kobayashi; Mikael Syväjärvi
Abstract
Dear Readers, A very Happy New Year 2017!International Association of Advanced Materials (IAAM, www.iaamonline.org) is pleased to announce cruise congress in Asia, Europe and America in year 2017 with collaboration of VBRI Press AB, Sweden (www.vbripress.com). The goal of congresses is to provide ...
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Dear Readers, A very Happy New Year 2017!International Association of Advanced Materials (IAAM, www.iaamonline.org) is pleased to announce cruise congress in Asia, Europe and America in year 2017 with collaboration of VBRI Press AB, Sweden (www.vbripress.com). The goal of congresses is to provide a global platform for researchers and engineers coming from academia and industry to present their research results and activities in the field of fundamental and interdisciplinary research of materials science and technology.
Research Article
Sandeep Kumar Singh; Amit Kumar Yadav; M. J. Akhtar; K. K. Kar
Abstract
Microwave absorbing material of nickel coated exfoliated graphite (Ni-EG) was prepared by electroless deposition in alkaline coating bath. The coating time, which is an important factor to achieve good coverage of Ni particles over exfoliated graphite (EG), was properly controlled during the process. ...
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Microwave absorbing material of nickel coated exfoliated graphite (Ni-EG) was prepared by electroless deposition in alkaline coating bath. The coating time, which is an important factor to achieve good coverage of Ni particles over exfoliated graphite (EG), was properly controlled during the process. Morphology and phases of Ni-EG were investigated by means of SEM and XRD, respectively. Electromagnetic (EM) properties of Ni-EG/epoxy composites were recorded using VNA over the frequency range of 2-18 GHz. Ni-EG/epoxy composites exhibit significant microwave absorption properties for coating time 10, 20, 30 and 40 minutes. Specially, reflection loss value reached -23.7 dB at 10.9 GHz with 6.0 GHz (8.1-14.1 GHz) and 2.0 GHz (10.1-12.1 GHz) of -10 and -20 dB absorption bandwidths, respectively for 40 minutes of deposition time. Therefore, the proposed material has a great potential for stealth applications. Copyright © 2016 VBRI Press.
Research Article
Trilok K. Pathak; L. P. Purohit
Abstract
ZnO and ZnO:N thin films were deposited on plane glass substrate using RF sputtering method. The crystalline structure and surface morphology of the film was investigated using XRD and SEM. The XRD patterns of ZnO thin films have largest crystalline orientation for the (002) peak and shows wurtzite structure. ...
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ZnO and ZnO:N thin films were deposited on plane glass substrate using RF sputtering method. The crystalline structure and surface morphology of the film was investigated using XRD and SEM. The XRD patterns of ZnO thin films have largest crystalline orientation for the (002) peak and shows wurtzite structure. The ZnO thin films composed of dance packing, grains without any cracks indicating uniform grain size distribution. The transmittance and absorbance of ZnO thin film was measured using UV-VIS-IR spectrophotometer in the wavelength range 200 nm-800 nm. The band gap of ZnO film was3.26 eV calculated by Tauc’s plot method. Photoluminescence property was also investigated at the excitation wavelength 325 nm. A.C. conductivity measurements carried out on the ZnO/ZnO:N thin films at room temperature in the frequency range 10 KHz to 0. 1MHz. This measurement also helps to distinguish between localized and free band conduction.The study demonstrated that ZnO and ZnO:N thin films fabricated by RF sputtering method can be used in electronicand optoelectronic applications due to high transmittance in visible region, large bandgap and localized conduction. Copyright © 2016 VBRI Press.
Research Article
Kirandeep Singh; Shuvam Pawar; Davinder Kaur
Abstract
Silicon integrated vertically aligned Ni-Mn-In nanorod arrays having ~100 nm length were investigated for shape memory behavior and magnetocaloric effect. The room temperature X-ray diffraction (XRD) patterns revealed the (220) oriented pure austenitic cubic phase growth of Ni–Mn–In nanorods. ...
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Silicon integrated vertically aligned Ni-Mn-In nanorod arrays having ~100 nm length were investigated for shape memory behavior and magnetocaloric effect. The room temperature X-ray diffraction (XRD) patterns revealed the (220) oriented pure austenitic cubic phase growth of Ni–Mn–In nanorods. The systematic thermo-magnetic (M-T) plots, resistance vs. temperature (R-T) measurements, as well as the negative slope of Arrott plots (H/M vs. M2) curves revealed the existence of significant shape memory effect in 100 nm Ni-Mn-In rods between 230 ≤ T≤ 294 K region. The formation of narrow hysteresis between field cooled (FC) and field warm (FW) curves in contrast to previous studies which reported broadness in the martensitic transformation temperature regime with decreasing thickness [1], can be ascribed to reduced substrate clamping effect due to vertically aligned growth of Ni-Mn-In. The magnetocaloric curves evaluated from M-H study indicates that large magnetic field magnitude dependent entropy change occurs in Ni-Mn-In rods, a maximum attainable ΔSM ~ 0.4 mJ/cc.K was observed at 275 K. Such vertically aligned growth of Ferromagnetic Shape Memory Alloys (FSMA’s) thin films over semiconductor substrate exhibiting significant shape memory behavior could prove useful in many MEMS/NEMS applications as well as opens possibility of futuristic self-cooled spintronics devices like magneto-electric random access memory (ME-RAM). Copyright © 2016 VBRI Press.
Research Article
Yuvraj S. Malghe; Atul B. Lavand
Abstract
Here, we report on microemulsion synthesis of nitrogen (N) doped TiO2 quantum dots (QDs) with improved visible-light response. XRD, FTIR, XPS, EDX and Raman spectroscopy confirms that N was doped successfully in TiO2 lattice. SEM and TEM study confirms spherical morphology of N-doped TiO2 QDs. N-doped ...
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Here, we report on microemulsion synthesis of nitrogen (N) doped TiO2 quantum dots (QDs) with improved visible-light response. XRD, FTIR, XPS, EDX and Raman spectroscopy confirms that N was doped successfully in TiO2 lattice. SEM and TEM study confirms spherical morphology of N-doped TiO2 QDs. N-doped TiO2 sample exhibit a narrower band gap and stronger visible light absorption as compared to pure TiO2. The assistance of the N enhances the photocatalytic activity in the visible light region by promoting the separation of the photo generated electrons and holes to accelerate the transmission of photocurrent carrier. Photocatalytic activity study evaluated for the degradation of acifluorfen herbicide under visible-light irradiation, demonstrated that N-doped TiO2 sample is more active than pure and commercial TiO2. The high visible-light photocatalytic activity is attributed to the anatase crystalline phase, small crystallite size, strong visible light absorption capacity and superior electron-hole charge carrier’s separation efficiency. The photoluminescence (PL) study was employed to test hydroxyl (•OH) radicals, which show that N-doped TiO2 helps to produce •OH radicals and favors to enhance its photocatalytic activity. N doped TiO2 quantum dots prepared in this work exhibit better photocatalytic activity and hence having a potential to use as a photocatalyst for the degradation of harmful organic chemicals, dyes and drugs coming out from industries and will help to keep environment clean and safe. Copyright © 2016 VBRI Press.
Research Article
Shahadat Hussain; Ashish K. Jain; Md. A. Ansari; Abhishek Pandey; Rupa Dasgupta
Abstract
Copper based shape memory alloys are studied throughout the world for their high transition temperatures and high thermal stability. Among Copper based shape memory alloys(SMAs), Cu-Al-Mn SMAs have shown good ductility and high transition temperature. Only those alloy systems that can show the formation ...
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Copper based shape memory alloys are studied throughout the world for their high transition temperatures and high thermal stability. Among Copper based shape memory alloys(SMAs), Cu-Al-Mn SMAs have shown good ductility and high transition temperature. Only those alloy systems that can show the formation of β phase are capable to demonstrate the shape memory properties. In this paper the effects of the alloying elements on the formation of martensite phase have been studied exclusively. Addition of 1 wt% of Fe, Cr and Ti to the Cu-12.5Al-5Mn shape memory alloy has been investigated in detail. Therefore, four alloys have been synthesized through liquid metallurgy route using pure metals of 99.9% purity in a melting furnace weighing 1kg each. Samples were heat treated at the temperature of 920˚C for 2 hours and then quenched in ice water. The optical micrographs show the formation of the martensite structures in all the samples except in the samples in which 1 wt% Fe was added. X-Ray diffractions also revealed the same facts as obtained in the optical microscopy. Vickers Hardness of all four samples were carried out. The result shows no sign of martensite formation in sample containing Fe; therefore, this alloy should not be used for further study in the direction of understanding shape memory behaviors of the copper based shape memory alloys. Moreover, it was also observed that the addition of Cr yielded good martensitic formation as compared to the alloy containing Ti. Copyright © 2016 VBRI Press.
Research Article
Rajat K. Saha; Mrinal K. Debanath; Eeshankur Saikia; Vedant V. Borah; Kandarpa K. Saikia
Abstract
ZnO based nanoparticles find a wide range of applications starting from biosensors and drug-delivery systems to solar cells. Keeping an eye on the prospect for an application in the field of biotechnology, we analyze Cu-doped ZnO nanoparticles after the fabrication and necessary characterization of the ...
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ZnO based nanoparticles find a wide range of applications starting from biosensors and drug-delivery systems to solar cells. Keeping an eye on the prospect for an application in the field of biotechnology, we analyze Cu-doped ZnO nanoparticles after the fabrication and necessary characterization of the XRD data obtained, by using the tools of Nonlinear Dynamical Theory (NLD). One of the tools used called Lyapunov Exponent, bears the signature of the dynamical evolution of the particles as well as structure formation. This is calculated in order to quantify the underlying strange attractor present in the nanosystems, which happens to be the driving force behind the structure formation. The changes in the values of this parameter with the variation of the physical and chemical conditions, would pave the way for an efficient calibration for meaningful biological applications, which happens to be the focus of the present work. Differently sized ZnO nano particles are obtained by changing dopant percentage for inhibiting human pathogenic bacteria. Calibrations are made between the Zone of Inhibition (ZOI) and Lyapunov Exponent to obtain the required dopant percentage for a given ZOI vis-à-vis the same anti-bacterial effectiveness in terms of ZOI of a ZnO doped nano particle. Copyright © 2016 VBRI Press.
Research Article
Azizurrahaman Ansari; Vishal Kumar Chakradhary; M. J. Akhtar
Abstract
In this article, an effort is made to synthesize the nickel ferrite nanoparticles via chemical co-precipitation method using the metal nitrates as precursors. The x-ray diffraction pattern of the as-synthesized powder sample indicates the formation of nickel ferrite with iron oxide and other impurity ...
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In this article, an effort is made to synthesize the nickel ferrite nanoparticles via chemical co-precipitation method using the metal nitrates as precursors. The x-ray diffraction pattern of the as-synthesized powder sample indicates the formation of nickel ferrite with iron oxide and other impurity phases. The heat treatment of the as-synthesized powder at 600oC assists in the formation of inverse spinel phase of nickel ferrite accompanying with some fraction of iron oxide phase. The field emission scanning electron microscopy of the heat treated sample reveals the irregular particle size and shape with fine microstructures, while as-synthesized sample shows the lamina like particle morphology. The magnetization curve(M-H curve) of the heat treated sample shows the ferrimagnetic behavior with very small (negligible) values ofremanent magnetization and coercive field. Such type of magnetic characteristic indicates the signature of superparamagnetism (Mr ~ 0, Hc ~ 0) in the heat treated nickel ferrite nanoparticles with significant value of the saturation magnetization (Ms). The superparamagnetic effect in the nickel ferrite particles has great potential in the field of biomedicine for certain applications such as the effective drug delivery, and for enhancing the contrast in case of magnetic resonance imaging. Copyright © 2016 VBRI Press.
Research Article
K. Srilatha; D. Bhagawan; V. Himabindu
Abstract
Hydrogen is an environmental friendly fuel, which has the potential to significantly used of fasil files; however several important challenges must defeat before it can be extensively used. Thermo catalytic decomposition of methane (TCD) is one of the most useful method, which will meet the future demand ...
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Hydrogen is an environmental friendly fuel, which has the potential to significantly used of fasil files; however several important challenges must defeat before it can be extensively used. Thermo catalytic decomposition of methane (TCD) is one of the most useful method, which will meet the future demand and hence an attractive route for COx free production of hydrogen which is essential in fuel cell. In the present study, we made an attempt on hydrogen production with Cu-Al2O3 and 5, 10, 15 & 20wt% of Ni modified Ni/Cu-Al2O3 catalysts. It is also observed that, the conversion order is Cu-Al2O3<5 wt% Ni/Cu-Al2O3 ~ 20 wt% Ni/Cu-Al2O3 <15 wt% Ni/Cu-Al2O3 < 10 wt% Ni/Cu-Al2O3 catalysts. It is observed that, while increasing the loadings of nickel in Ni/Cu-Al2O3 the efficiency of thermo catalytic decomposition of methane is also increasing. Among five catalysts prepared the 10wt% Ni/Cu-Al2O3 catalyst is showing good catalytic activity.SEM images of catalysts after thermo catalytic decomposition of methane shows the formation of carbon nanofibers. XRD patterns of the Cu-Al2O3 and 5,10,15 & 20wt%Ni/Cu-Al2O3 catalysts revealed, fairly crystalline peaks of which may responsible for the increase in the catalytic life and the formation of carbon nanofibers. The optimum hydrogen production of 70 volume % was observed with 10 wt% Ni/Cu-Al2O3 catalyst along with hydrogen carbon fibers were also found, which can be used as catalyst support. Copyright © 2016 VBRI Press.
Research Article
Amer Eid Amer; Min Y. Koo; Soon H. Hong
Abstract
This work reports the results of an investigation of micro-alloyed steel plates subjected to high heat input (4.5 kJ/mm), simulating the thermal cycle of heat affected zone (HAZ) conducted by induction heating in a computer controlled weld thermal cycle simulator. Three samples of steels having Carbon ...
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This work reports the results of an investigation of micro-alloyed steel plates subjected to high heat input (4.5 kJ/mm), simulating the thermal cycle of heat affected zone (HAZ) conducted by induction heating in a computer controlled weld thermal cycle simulator. Three samples of steels having Carbon and Nickel content of 0.08 and 0.8 wt. %, respectively, as well as different Aluminum contents of 0.004, 0.026, and 0.057 wt. %, were investigated. The variation in microstructure, hardness and crack tip opening displacement (CTOD) fracture toughness properties with Al contents were evaluated, and compared with another set of the three samples of steel having the same chemical compositions but with neglected amount of Ni content. The fracture toughness tests revealed the decrease in their CTOD values due to increasing Al contents. In contrast, the hardness measuring revealed the increase of the hardness due to increasing Al wt. %. On the other hand, it was found that the presence of 0.8 wt. % Ni promotes the formation of finer microstructure at a high heat input of 4.5kJ/mm, which leads to higher fracture toughness CTOD value(δ =1.05), which is two times the value of those which have traces of Ni content(δ =0.52). However, the hardness test results showed similar values in each case regardless the amount of Ni contents. Meanwhile, the aspect ratio of the nucleated acicular ferrite was found to be increasing together with the refinement of its grain size due to Ni addition. Hence, it can be concluded that such development and the specific additions of Aluminum positively affects the microstructures and mechanical properties of the investigated steels and their used as marine structural steel. Copyright © 2016 VBRI Press.
Research Article
P. Prabeesh; P. Saritha; I Packia Selvam; S. N. Potty
Abstract
Kesterite thin films have been fabricated by chemical spray pyrolysis technique using less toxic organic solvent followed by annealing at different temperatures in inert nitrogen atmosphere. Phase formation and structural evolution were studied by XRD and Raman spectroscopy. The films annealed at 450°C ...
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Kesterite thin films have been fabricated by chemical spray pyrolysis technique using less toxic organic solvent followed by annealing at different temperatures in inert nitrogen atmosphere. Phase formation and structural evolution were studied by XRD and Raman spectroscopy. The films annealed at 450°C and 500°C exhibited excellent properties required for photovoltaic absorber materials. UV-Vis spectroscopy was used to estimate absorption coefficient and band gap; the films annealed at 450°C and 500°C showed band gap of 1.65eV and 1.51eV, respectively. Surface morphological properties and film thickness were studied by FESEM and electrical properties by Hall measurement system. Films annealed at 500°C showed densely packed grains with thickness ~ 1.2μm. Electrical properties of the films annealed in nitrogen atmosphere were in good agreement with the values previously reported for CZTS thin films. Copyright © 2017 VBRI Press
Research Article
M. Malligavathy; D. Pathinettam Padiyan
Abstract
Phase pure bismite nanoparticles were successfully prepared by means of hydrothermal method by varying the precursor solution pH from 10 to 13. The as-prepared nanoparticles were characterized by different techniques such as X-ray diffraction pattern (XRD), Raman spectroscopy, Scanning electron microscopy ...
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Phase pure bismite nanoparticles were successfully prepared by means of hydrothermal method by varying the precursor solution pH from 10 to 13. The as-prepared nanoparticles were characterized by different techniques such as X-ray diffraction pattern (XRD), Raman spectroscopy, Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDX). The effects of pH on the structural properties of these nanoparticles were corroborated using XRD and Raman spectrum. From the XRD pattern it is found that all the samples are polycrystalline in nature and the Raman spectra are used to confirm the phase transformation of the Bi2O3 nanoparticles. At the low pH value, the SEM image reveals that as-prepared samples are homogeneous with particle size of ~ 25 nm and with the increase in the pH value spherical particle forms uniform blocks like morphology for both the samples prepared at the pH 12 and 13. Copyright © 2017 VBRI Press.
Research Article
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.
Research Article
Hemlata J. Sharma; Megha A. Salorkar; Subhash B. Kondawar
Abstract
Electrospun nanofibers of Polyaniline (PANI)/SnO2 composite based gas sensor for hydrogen (H2) and carbon monoxide (CO) gas were prepared by electrospinning technique. The synthesized material was characterized using UV-Visible, XRD and SEM-EDX analyses. The average diameter of PANI/SnO2 composite was ...
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Electrospun nanofibers of Polyaniline (PANI)/SnO2 composite based gas sensor for hydrogen (H2) and carbon monoxide (CO) gas were prepared by electrospinning technique. The synthesized material was characterized using UV-Visible, XRD and SEM-EDX analyses. The average diameter of PANI/SnO2 composite was found to be high as compared to that of pristine SnO2 nanofibers having 200 nm diameter may be due to micelle formation of PANI on the surface of SnO2 nanofibers.The enhanced sensing properties in the form of sensitivity factor, time taken to response and recovery during exposure and de-exposure of Gas and repeatability were studied. The SnO2/PANI composite nanofibers showed high sensitivity and response to H2 gas compared to CO gas to 0.1% and maximum sensitivity was observed at 35˚C for H2 gas. Fast Response-Recovery Time for 1000-5000 ppm of H2 i.e. less than 30 secs were observed. Due to room temperature operation of the sensor, it is promising for environmental applications. The results indicate that aligned SnO2/PANI composite fibers are promising candidate for fast detection of H2 gas. Copyright © 2017 VBRI Press.
Research Article
Sanatombi Sorokhaibam; Ibetombi Soibam; Sumitra Phanjoubam
Abstract
Substituted lithium ferrite having the chemical formula Li0.35 Ni0.1 Mn0.1 Zn0.2 Fe2.35 O4 have been synthesized by the citrate precursor method. The sample was given pre-sintering at 650oC in a conventional furnace. Final sintering was carried out at 900oC in a conventional surface and another ...
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Substituted lithium ferrite having the chemical formula Li0.35 Ni0.1 Mn0.1 Zn0.2 Fe2.35 O4 have been synthesized by the citrate precursor method. The sample was given pre-sintering at 650oC in a conventional furnace. Final sintering was carried out at 900oC in a conventional surface and another in a microwave furnace. The spinel phase structure of the conventional (CS) and microwave sintered (MS) samples was confirmed by the XRD patterns. From the analysis of XRD data, the crystallite size of the samples was estimated and smaller crystallite size was observed in the microwave sintered sample. Scanning Electron Microscopy (SEM) was also carried out. The dielectric studies were investigated. Room temperature dielectric constant ( ) and dielectric loss (tan d) were studied as a function of frequency. Experimental results show dispersion for variation of dielectric constant and dielectric loss tangent with frequency for both CS and MS sample. However, microwave sintered sample show lower dielectric constant and losses. Possible mechanism is being discussed. Copyright © 2016 VBRI Press.
