Journal of Modern Materials
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55 research outputs found
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Photon Multiplicity Distributions at Heavy Ion Au+Au, Pb+Au, Pb+Pb Interactions
No full textThe experimental distributions for Heavy ion interaction, Au+Au, Pb+Au, Pb+Pb have been fitted to polynomial fit of 4th order to look at minor differences in multiplicity distributions for different targets at heavy ion collisions experiment. The multiplicity distributions found similar; except for small differences which may be of statistical in nature. This analysis supports the hypothesis that geometrical aspects play a dominant role in particle production in heavy ion interactions
Effect of Microwave Sintering on Electrical Properties of Sr-deficient and Bi-rich Strontium Bismuth Niobate (Sr0.8Bi2.2Nb2O9) Ferroelectric Ceramic
No full textNonstoichiometric strontium bismuth niobate (Sr0.8Bi2.2Nb2O9: SBN) ceramic was prepared using conventional solid-state reaction and microwave sintering methods. Complex impedance spectroscopy (CIS) has been used to investigate the intra and intergranular contribution to the impedance SBN ceramics as a function of temperature and frequency. Complex impedance Cole‑Cole plots were used to interpret the relaxation mechanism in SBN ceramic which showed a non-Debye relaxation. The grain and grain boundary contribution to conductivity have been estimated from the Cole‑Cole plots. The bulk (grain) resistance of both samples was found to decrease with rise in temperature indicating negative temperature coefficient of resistance (NTCR) type behavior like that of semiconductors. The microwave sintered SBN was found to have low value of bulk resistance indicating more increase in conductivity as compared to conventionally sintered SBN. The temperature dependence of the relaxation time was found to obey the Arrhenius law. Studies of electrical modulus show the presence of hoping conduction mechanism in SBN
Effect of Gradual Variation of Metal Composition on Stresses Generated in Weld Interfaces
No full textDissimilar metal joints formed by conventional welding creates residual stress at the interface and leads to an earlier failure than expected. The conventional methods are rapidly being replaced by advanced techniques, such as transition layer grading. This kind of transition grading aims to form the welding component akin to functionally graded material. The present paper aims to analyze different stress concentration conditions by varying temperatures, loads, and the number of transition layers. The material in the weld zone varied linearly when the number of layers was increased, which is analogous to functionally graded materials. The finite element model of a dissimilar metal welded pipe was simulated using ANSYS Workbench 14.5. Based on the executed simulations, it was observed that residual stress at the weld interface decreased as the number of layers increased up to a certain critical number of graded layers. Furthermore, negligible effect on stress reduction has been observed beyond this critical number of graded layers
Comparative Study on Electrical and Dielectric Properties of Sintered Nano and Micro Silicon Nitride Ceramics
No full textIn the present work we have studied the electrical conductivity, dielectric constant and dielectric loss of Sintered Silicon Nitride ceramics. In this study it was found that the grain size has great impact on electrical conductivity and dielectric properties of Sintered Silicon Nitride Ceramics. The result shows more efficiency of electrical and dielectric properties with nano sized grains. The sintering was performed in a programmable furnace at 950 K. The dc conductivity measured in the temperature range 300 K to 900 K. At higher temperature (T > 800 K), the dc conductivity increases exponentially with temperature for both of the investigated samples. Dielectric constant and loss are measured in the temperature range 300 K to 900 K with frequency range 1 KHz to 1 MHz. To confirm the grain size, the samples are characterized by the Scanning Electron Microscope (SEM). These types of samples can be used as a high temperature semi-conducting material
Low Temperature Combustion Processed Stable Al Doped ZnO Thin Film Transistor: Process Extendable up to Flexible Devices
No full textWe report combustion synthesis of polycrystalline Aluminium doped zinc oxide (AZO) at low temperature for next generation low cost, flexible thin film transistor (TFT) application. Solution processed AZO thin film has been characterized by X ray diffraction and atomic force microscopy to confirm crystallinity. In this research work TFT with solution processed AZO as channel layer has been fabricated on both rigid and flexible substrate which exhibits excellent electrical stability and improved field effect mobility of 1.2 cm2V-1S-1, threshold voltage of 15 V and on-off ratio of 106 as compared to pure ZnO based TFT. All the measurements have been carried out with varying Al concentration. Moreover, variation in defect density of AZO with Al concentration which essentially causes significant change in TFT’s performance is demonstrated by chemical composition and bonding state analysis using XPS. Our results suggest that low temperature solution processed AZO TFTs have a potential for low cost, flexible and transparent electronic applications