排序方式: 共有22条查询结果,搜索用时 15 毫秒
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Agrawal Prachi Ganesh Talari Mohamed Ali Wagdy 《Neural computing & applications》2021,33(11):5989-6008
Neural Computing and Applications - To obtain the optimal set of features in feature selection problems is the most challenging and prominent problem in machine learning. Very few human-related... 相似文献
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Ali H. Jawad S. Sabar Mohd Azlan Mohd Ishak Lee D. Wilson Siti Solehah Ahmad Norrahma M. K. Talari 《Chemical Engineering Communications》2017,204(10):1143-1156
Mesoporous-activated carbon was prepared from fallen coconut (Cocos nucifera) leaf, an agricultural waste through a microwave-induced H3PO4 activation process. The characterization of the coconut leaf–activated carbon (CAC) was evaluated through the iodine number, ash content, bulk density, and moisture content. Fourier transform infrared spectroscopy, scanning electron microscope, Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction, and pHPZC. CAC has a mesopore content of 84% with an average pore size of 36.5?Å and a large BET surface area of 632?m2/g. The uptake properties of the CAC with methylene blue was evaluated at different CAC dosage levels (0.2–10?g/L), initial pH (3–10), methylene blue concentration (50–350?mg/L), and time (0–360?min) using batch mode operation. The kinetic profiles were described by the pseudo-second-order kinetics. The equilibrium data were well fitted to the Langmuir model with a maximum monolayer adsorption capacity of 250?mg/g at 30°C. Thermodynamic functions indicate a spontaneous and exothermic nature of the adsorption process. This study indicates that coconut leaves are a promising renewable precursor that can be utilized to develop an efficient mesoporous-activated carbon. 相似文献
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Widyani Darham Ahmad Lutfi Anis Izzul Adli Mohd Arif Nagamothu Kishore Babu Mohamad Kamal Harun Mahesh Kumar Talari 《Transactions of the Indian Institute of Metals》2017,70(3):649-654
The current study has investigated the influence of zirconium (Zr) addition to Mg–3Ca–xZr (x = 0.3, 0.6, 0.9 wt%) alloys prepared using argon arc melting on the microstructure and impression properties at 448–498 K under constant stress of 380 MPa. Microstructural analysis of as-cast Mg–3Ca–xZr alloys showed grain refinement with Zr addition. The observed grain refinement was attributed to the growth restriction effect of Zr in hypoperitectic Mg–3Ca–0.3 wt% Zr alloys. Heterogeneous nucleation of α-Mg in properitectic Zr during solidification resulted in grain refinement of hyperperitectic Mg–3Ca–0.6 wt% Zr and Mg–3Ca–0.9 wt% Zr alloys. The hardness of Mg–3Ca–xZr alloys increased as the amount of Zr increased due to grain refinement and solid solution strengthening of α-Mg by Zr. Creep resistance of Mg–3Ca–xZr alloys increased with the addition of Zr due to solid solution strengthening of α-Mg by Zr. The calculated activation energy (Qa) for Mg–3Ca samples (131.49 kJ/mol) was the highest among all alloy compositions. The Qa values for 0.3, 0.6 and 0.9 wt% Zr containing Mg–3Ca alloys were 107.22, 118.18 and 115.24 kJ/mol, respectively. 相似文献
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M. Masturah I. Norezan A. K. Yahya A. Zakaria M. S. Mohd Deni M. K. Talari 《Transactions of the Indian Institute of Metals》2013,66(4):325-328
CaCu3Ti4O12 (CCTO) is well known to have colossal dielectric constant in the range of 105. However, CCTO has considerably high dielectric loss values (tanδ > 0.1) at room temperature and 1 kHz. In this work, addition of glass to CCTO was suggested in order to improve its dielectric properties. The effect of V2O5–TeO2 (VT) glass addition on microstructure and dielectric properties of CCTO ceramics were investigated. Dielectric measurements were carried out for (1 ? x) CCTO-(x) V2O5–TeO2 (x = 0, 0.03, 0.05, 0.10) samples in the frequency range of 102–106 Hz using impedance spectrometer. Electron micrographs showed that low melting VT glass addition facilitated the grain growth of CCTO. As VT glass amount increased, dielectric constant decreased. The drop, though within reasonable values (~105), may related to the presence of grain boundary glassy phase which itself has low dielectric constant. However, the dielectric loss of the composite has decreased after VT glass addition. The low melting V2O5–TeO2 glass aided in liquid phase sintering and improved the grain boundary resistance which resulted in decreased leakage currents. 相似文献
5.
Rafidah Razuan Nur Aimi Jani Mohamad Kamal Harun Mahesh Kumar Talari 《Transactions of the Indian Institute of Metals》2013,66(4):309-312
Properties of pure metals can be enhanced by alloying with other metallic or non-metallic elements according to the need. However, as multiple alloying elements in an alloy may lead to the formation of many intermetallic compounds with complex microstructures and poor mechanical properties, new types of metallic alloys called high entropy alloys with at least five elements with equimolar ratios were developed. In this study, FeNiAlCuCrTi x Nb y (x, y = 0, 0.5, 1.0, 1.5) alloys have been prepared using Ar arc melting technique. Microstructural studies using scanning electron microscope and XRD showed that Ti addition promoted secondary BCC2 phase whereas, Nb acted as FCC stabilizer. Samples with combined Nb and Ti addition showed FCC1 and FCC2 structure with Nb-rich FCC2 dendritic phase as dominant phase. Though, individual Nb and Ti additions have resulted in increased hardness, combined additions have resulted in highest hardness of 797 HV under 1 kg load. 相似文献
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Nurul Syahidah Sabri A. K. Yahya Mahesh Kumar Talari 《Transactions of the Indian Institute of Metals》2017,70(3):557-565
Raman and UV–Vis spectral analysis of xSrO–10PbO–(90 ? x)B2O3 glasses were carried out to elucidate the structural and optical behaviour due to borate anomaly. Raman analysis revealed that the glasses consisted of mainly trigonal groups (metaborate) and tetrahedral groups (ditri/dipentaborate and diborate) at lower SrO content. Concentration of diborate groups reached a maximum value at x = 30 mol% and were replaced by pyroborate, metaborate and orthoborate groups as SrO content in the glass increased. Maximum value of optical band gap (E opt ) and minimum values of electronic polarizability (αO2?), optical basicity (Λ) and refractive index (n) were obtained when x = 25 mol%, which was lower compared to maximum of diborate group (x = 30 mol%) as observed from Raman spectroscopic analysis. Observed mismatch in diborate groups and E opt maxima was attributed to the formation of weak coordinated covalent bonds during structural transformation and addition of cation with high polarizability to the xSrO–10PbO–(90 ? x)B2O3 glass. 相似文献
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Ain W. Q. Faisal M. K. Talari M. K. Darham W. Ratnam M. M. Kwon Y. Kim N. J. Prasada Rao A. K. 《Journal of Materials Engineering and Performance》2016,25(10):4310-4316
Journal of Materials Engineering and Performance - Reported work focuses on the effect of morphology of the Fe-rich intermetallic phases on the machinability of Al-alloy containing >2wt.%... 相似文献
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The effect of (Ba(0.6)Sr(0.4))TiO3(BST) addition on dielectric properties of CaCu3Ti4O(12) (CCTO) ceramic was investigated. Ceramic samples with the chemical formula (1-x)CaCu3Ti4O(12) + x(Ba(0.6),Sr(0.4))TiO3 (x=0, 0.05, 0.1, and 0.2) were synthesized from high purity oxide powders by the conventional solid-state synthesis method. X-ray diffraction (XRD) analysis showed the existence of BST as a secondary phase alongside CCTO. Scanning electron microscopy (SEM) investigation showed a slight decrease in grain size of doped CCTO samples. Density measurements showed that porosity content increased with increasing BST addition indicating low densification due to high melting point secondary phase addition. Dielectric constant of undoped CCTO (x=0) showed lack of stability with frequency which dropped drastically between 104 and 105Hz and accompanied by high dielectric loss. Addition of BST into CCTO caused the dielectric constant to slightly decrease but improved stability with frequency compared to the undoped sample. The decrease in dielectric constant of doped CCTO samples was suggested to be partly due to the decrease in average grain size and increase in porosity with BST addition. Nevertheless, a high value of dielectric constant was still maintained around ~104 range for all doped samples. The dielectric loss (tanδ) of all BST-doped samples was lower than that of pure CCTO sample at the frequency range of 103 to 105 Hz probably due to the increase of grains boundary resistivity. The activation energy of grains boundary (E(gb)) showed higher values as compared to the activation energy of grains (Eg ) for all samples and conforms to the internal barrier layer capacitor (IBLC) model. 相似文献
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N. Kishore Babu Mahesh Kumar Talari D. Pan J. Wei 《The International Journal of Advanced Manufacturing Technology》2013,65(9-12):1757-1767
The present study has investigated the influence of scandium additions on the structure and mechanical properties of AA2219 gas tungsten arc (GTA) weldments. Controlled amounts of scandium modified AA2319 fillers were introduced into the molten pool of AA2219 by predeposited cast inserts under different welding conditions in GTA welding. Full penetration GTA welds were prepared using alternating current. It was observed that grain size decreased with increasing amounts of scandium and gradual transformation from columnar to equiaxed grain morphology. The observed grain refinement was shown to result in an appreciable increase in fusion zone hardness, strength, and ductility. Room temperature hardness and tensile properties at different temperatures (room temperature, 100, 150, 200 and 250 °C) of weldments in the as-welded condition were observed and correlated with microstructure. The results show that the welds subjected to post-weld aging treatment have displayed superior hardness and tensile strength. 相似文献