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排序方式: 共有202条查询结果,搜索用时 15 毫秒
41.
M. S. Sreekala M. G. Kumaran Seena Joseph Maya Jacob Sabu Thomas 《Applied Composite Materials》2000,7(5-6):295-329
Oil palm fibres have been used as reinforcement in phenol formaldehyde resin. In order to improve the interfacial properties, the fibres were subjected to different chemical modifications such as mercerisation, acrylonitrile grafting, acrylation, latex coating, permanganate treatment, acetylation, and peroxide treatment. The effect of fibre coating on the interface properties has also been investigated. Morphological and structural changes of the fibres were investigated using scanning electron microscopy and IR spectroscopy. Mechanical properties of untreated and treated fibres were studied. Changes in stress–strain characteristics, tensile strength, tensile modulus and elongation at break of the fibres upon various modifications were studied and compared. The incorporation of the modified fibres resulted in composites having excellent impact resistance. Fibre coating enhanced the impact strength of untreated composite by a factor of four. Tensile and flexural performance of the composites were also investigated. Finally, inorder to have an insight into the failure behaviour, the tensile and impact fracture surfaces of the composites were analysed using scanning electron microscope. 相似文献
42.
Mesoporous MCM-41 material with high surface area and narrow pore size distribution was synthesized and used as a support for Mo, CoMo, and NiMo catalysts. The molybdenum loading was varied from 2-14 wt% on MCM-41. On 10 wt% Mo/MCM-41, the promoter Co or Ni concentration was varied from 1-5 wt%. All the catalyst samples were characterized by surface area, low temperature oxygen chemisorption, x-ray diffraction (XRD), and temperature programmed reduction methods. Characterization results show that Mo is well dispersed on MCM-41 up to 10 wt%. The catalytic activities were evaluated for thiophene hydrodesulphurization (HDS), cyclohexene hydrogenation (HYD), and furan hydrodeoxygenation (HDO). All three catalytic functionalities vary in a similar manner to that of oxygen chemisorption as a function of Mo loading, indicating that there is a correlation between oxygen uptake and catalytic sites. The activities of these catalysts were compared with γ-Al2O3- and amorphous SiO2-supported catalysts. It was found that MCM-41-supported Mo catalysts displayed superior activities. 相似文献
43.
In situ performance evaluation of spray polyurethane foam in the exterior insulation basement system (EIBS) 总被引:1,自引:0,他引:1
M.C. Swinton W. Maref M.T. Bomberg M.K. Kumaran N. Normandin 《Building and Environment》2006,41(12):1872-1880
In 1995, a joint research project1 with the Institute for Research in Construction was initiated to assess the in situ thermal performance of a number of insulation products used as exterior basement insulation in contact with the ground. 相似文献
44.
K. Thangaraju R. Kumaran K. Asokan P. Ramamoorthy D. Kanjilal 《Polymer-Plastics Technology and Engineering》2013,52(5):479-482
The effect of swift heavy ion (SHI) irradiation on the optical properties of Tris-(8-hydraxyquinoline) aluminum (Alq3) thin films has been studied. It is confirmed that PL and lifetime of SHI irradiated Alq3 thin films irradiated both at room temperature and low temperature decrease for increasing ion fluences indicating the transfer of excitons energy to unstable cationic Alq3 species. It is also confirmed that PL and lifetime of Alq3 thin films irradiated at low temperature decrease largely compared to that of at the room temperature indicating that a large number of unstable cationic Alq3 species are generated by SHI irradiation. 相似文献
45.
The ageing behavior due to the effects of heat, ozone, γ‐ radiation, and water on ethylene propylene diene monomer rubber/styrene butadiene rubber (EPDM/SBR) blends was studied. The tensile strength, crack initiation, ozone ageing, gamma radiation, and water resistance of the blends were measured and used to determine the extent of ageing. Tensile strength of blends of different compositions increased after thermal ageing for 96 h at 100°C probably due to the continued cross‐linking. It has been observed that an increase in EPDM in the blends improves the ozone resistance of the blends. Crack initiation was noted only in blends with lesser amount of EPDM and the cracks in such blends were found deeper, wider and continuous. With 15 kGy irradiation dose, the tensile strength of the blends found to be decreased while it increased with 80 kGy dosage of γ‐radiation. The elongation at break showed a decreasing trend with increased dosage of γ‐radiation. It has also been observed that the EPDM rich blends showed negligible water uptake. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
46.
S. Muthu Kumaran V. Rajendran T. Jayakumar P. Palanichamy P. Shankar Baldev Raj 《Journal of Alloys and Compounds》2008,464(1-2):150-156
Ultrasonic velocities and attenuation measurements have been carried out to characterise the fine scale precipitation events in a slow heat-treated 8090 Al–Li alloy. The alloy was subjected to a slow heating (at the rate of 10 K h−1) to the temperature of 463 K, before and after solution annealing at 803 K for 1 h. The changes in bulk modulus, Young's modulus and Poisson's ratio have been obtained from the ultrasonic velocity data. The variation in hardness and density has been found to be consistent with the changes in velocities and elastic constant. The ultrasonic on-line measurements from 300 to 623 K reveal clearly all the four transitions, including the formation of GP zones at 368 K, formation of δ′ at 470 K, dissolution of δ′ at 532 K and the formation of equilibrium S′ and δ phases at 590 K. The first differential of temperature dependent ultrasonic parameters is found to be particularly effective in clearly diagnosing all the fine scale precipitation/dissolution events. Differentiation between the precipitation and dissolution type reactions is also possible from careful analysis of the first differential plots. 相似文献
47.
An activity-directed fractionation and purification process was used to identify the DPPH (l,l-diphenyl-2-picrylhydrazyl) free radical-scavenging components of Coleus aromaticus Benth. Fresh leaves of C. aromaticus were extracted with water and then separated into hexane, ethyl acetate, and water fractions. Among these, only the ethyl acetate phase showed strong DPPH radical-scavenging activity in vitro, when compared with water and hexane phases. The ethyl acetate fraction was then subjected to separation and purification using Sephadex LH-20 chromatography. Three compounds showing strong DPPH radical-scavenging activity were shown, by spectral methods (1H NMR, 13C NMR, and MS) and by comparison with literature values, to be rosmarinic acid, chlorogenic acid and caffeic acid. In addition, HPLC identification and quantification of isolated compounds were also performed. Rosmarinic acid was found as a major component and principally responsible for the radical-scavenging activity of C. aromaticus. 相似文献
48.
Kumaran S. Thirumalai Ko Tae Jo Kurniawan Rendi Li Changping Uthayakumar M. 《Journal of Mechanical Science and Technology》2017,31(8):3949-3954
Journal of Mechanical Science and Technology - This study discusses the development of an Adaptive neuro–fuzzy inference system (ANFIS) model for determining the surface roughness (Ra) during... 相似文献
49.
Lorenzo Vigna Andrea Fasoli Matteo Cocuzza Fabrizio C. Pirri Luisa D. Bozano Marco Sangermano 《大分子材料与工程》2019,304(2)
A new flexible polymeric gas sensor is developed by photocrosslinking poly(ethylene glycol) diacrylate resin (PEGDA) containing multi‐walled carbon nanotubes (MWCNTs) as conductive filler. The cured material shows a percolative threshold conductivity which changes when in contact with various gas analytes with different chemical and physical properties. The different behavior of the sensors toward the different gases is explained either on the basis of chemical affinity toward the polymeric matrix or due to the interactions that can occur between the analyte and the surface of the nanotubes in the case of the aromatic gas. 相似文献
50.
Corrosion of Borosilicate Glasses Subjected to Aggressive Test Conditions: Structural Investigations 下载免费PDF全文
Vidya S. Thorat Raman K. Mishra Sudarsan V. Kumaran Amar Kumar Rajesh K. Vatsa Chetan P. Kaushik Avesh K. Tyagi 《Journal of the American Ceramic Society》2016,99(10):3251-3259
Sodium borosilicate (NBS) and barium sodium borosilicate (BBS) glasses, used for immobilization of high‐level nuclear waste with compositions (SiO2)0.477(B2O3)0.239(Na2O)0.170(TiO2)0.023(CaO)0.068(Al2O3)0.023 and (SiO2)0.482(B2O3)0.244(Na2O)0.220(BaO)0.054 were subjected leaching experiments under hydrothermal conditions in an autoclave at 200°C for different time durations. Morphological and structural transformations associated with leaching, have been monitored with techniques like XRD, SEM, solid‐state nuclear magnetic resonance. XRD and SEM along with NMR studies have confirmed that, upon leaching, formation of an aluminosilicate phase, Zeolite‐P (Na6Al6Si10O32·12H2O), occurs with NBS glass. BBS glass upon subjecting to the same conditions leads to formation of multiple amorphous phases having Q4 (silica rich phase) and Q3 structural units of Silicon along with structurally modified residual glass. Upon leaching BO3 structural units preferentially get released from BBS glass. Comparison of results with international simple glass confirmed that, for the latter, mass loss rates are one order of magnitude lower. 相似文献