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41.
In the present study an effort has been made to optimize the machining conditions for electric discharge machining of LM25 Al (7 Si, 0.33 Mg, 0.3 Mn, 0.5 Fe, 0.1 Cu, 0.1 Ni,.2 Ti) reinforced with green bonded SiC particles with approximate size of 25 mum. Polynomial models were developed for the various EDM characteristics such as metal removal rate, tool wear rate and surface roughness in terms of the process parameters such as volume fraction of SK, current and pulse time. The models were used to optimize the EDM characteristics using nonlinear goal programming. 相似文献
42.
R. Karthikeyan K. Raghukandan R. S. Naagarazan B. C. Pai 《Metals and Materials International》2000,6(6):539-547
The present investigation focuses on the face milling characteristics of LM25Al-SiC particulate composites produced through
stir casting. Experiments were conducted according to an L27 orthogonal array and mathematical models were developed for such
machining characteristics as flank wear, specific energy and surface roughness whose adequacy was checked. The insignificant
effects present in the models were eliminated using a t-test. Goal programming was employed to optimize the cutting conditions
by considering such primary objectives as maximizing the metal removal rate and minimizing tool wear, specific energy and
surface roughness. 相似文献
43.
将铁鞣与铬鞣进行了优化结合,这种鞣制技术不仅可以加工出质量上乘的皮革制品,同时又可以满足废液中铬与铁的含量低于100mg/kg的标准。此工艺制造的皮革可耐沸水试验,阐述了其鞣制技术和鞣制机理。对铁鞣法在加工山羊绒面革和绵羊全粒面服装革中出现的问题进行了研究。用扫描电镜对鞣革的结构特性进行了研究,对成革的物理机械性能及染色特性也做了分析和阐述。 相似文献
44.
Naranappa Vijaya Subramaniyan Selvasekarapandian Shunmugavel Karthikeyan Moni Prabu Natarajan Rajeswari Chinnappa Sanjeeviraja 《应用聚合物科学杂志》2013,127(3):1538-1543
This work aims at developing and characterizing a proton conducting polymer electrolyte based on Poly(N‐vinyl pyrrolidone) (PVP) doped with ammonium bromide (NH4Br). Proton conducting polymer electrolytes based on PVP doped NH4Br in different molar ratios have been prepared by solution casting technique using distilled water as solvent. The XRD pattern confirms the dissociation of salt. The FTIR analysis confirms the complex formation between the polymer and the salt. The conductivity analysis shows that the polymer electrolyte with 25 mol % NH4Br has the highest conductivity equal to 1.06 × 10?3 S cm?1 at room temperature. Also it has been observed that the activation energy evaluated from the Arrhenius plot is low (0.50 eV) for 25 mol % NH4Br doped polymer electrolyte. The influence of salt concentration on dc conductivity and activation energy of the polymer electrolyte has been discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
45.
T. Karthikeyan Arup Dasgupta S. Saroja M. Vijayalakshmi 《Journal of Materials Engineering and Performance》2005,14(2):241-248
The successful replacement of the present generation of corrosion-resistant materials (nitric acid-grade stainless steel and
Ti) by Ti-5Ta-1.8Nb, which has better corrosion resistance, depends on its weldability characteristics. This article presents
the results of a study on the fabrication, qualification, and microstructural characterization of the welds. Welding was carried
out using the direct current electrode negative (DCEN) polarity tungsten inert gas (TIG) (manual) welding method with high-purity
Ar shielding. Testing was carried out as per the ASME standard (section IX, welding and brazing). Qualification tests found
that the weldment met the required properties. The weldment showed heterogeneous microstructures, which are rationalized based
on differences in phase transformation mechanisms that are dictated by the thermal cycles experienced by various microscopic
regions. The results, described in this article, confirm that the weldability of the developmental Ti-Ta-Nb alloy is excellent.
A preliminary evaluation of the corrosion behavior of the welds showed rates comparable to that of the base metal, establishing
that this alloy could be considered as an alternative material for use in highly corrosive environments. 相似文献
46.
The present work is focused on optimization of machining characteristics of Al/SiCp composites.The machining characteristics such as specific energy,tool wear and surface roughness were studied.The parameters such as volume fraction of SiC,cutting speed and feed rate were considered.Artificial neural networks(NN) was used to train and simulate the experimental data.Genetic algorithms(GA) was interfaced with ANN to optimize the machining conditions for the desired machining characteristics .Validation of optimized results was also performed by confirmation experiments. 相似文献
47.
V Karthikeyan R Parasuraman V Shah E Vera KK Venkat 《Canadian Metallurgical Quarterly》2003,3(10):1289-1294
Thrombotic microangiopathy (TMA) in renal transplant recipients is commonly associated with calcineurin inhibitors (CNIs), though several factors such as vascular rejection, viral infections and other drugs may play a contributory role. We report a series of 29 patients with TMA, all of whom were on CNIs. Though plasma exchange (PEx) is widely used to treat TMA, therapeutic guidelines are not well defined. All our patients were treated with PEx and discontinuation of CNIs. Thrombotic microangiopathy was diagnosed at a median of 7 days post-transplant. The mean decrease in Hgb and platelets during TMA was 66% and 64%, respectively, and peak serum creatinine during TMA was 7.4 +/- 2.9 mg%. Mean duration of PEx therapy was 8.5 (range 5-23) days. Recovery of platelet count to 150K/mcL and Hgb to 8-10 g/dL were used as endpoints for PEx. Twenty-three/29 (80%) patients recovered graft function after PEx. Twenty/23 (87%) patients who recovered were placed back on CNl. Nineteen/20 (95%) patients tolerated reinstitution of CNl without recurrence of TMA. In post-transplant TMA, PEx was associated with a graft salvage rate of 80%, reversal of hematological changes can be used as the endpoint for PEx therapy and CNl can be reintroduced without risk of recurrence in the majority of patients. 相似文献
48.
N. Satyanarayana A. Karthikeyan M. Venkateswarlu 《Journal of Materials Science》1996,31(20):5471-5477
A new quaternary fast-ion conducting silver molybdo-arsenate [Agl-Ag2O-(MoO3 + As2O5)] (SMA) glassy system has been prepared using the melt-quenching technique for various dopant salt (Agl) concentrations by fixing the formers (MoO3 + As2O5) composition and the modifier (Ag2O) to formers (M/F) ratio. The prepared compounds were characterized by X-ray diffraction. The impedance measurements were made on different Agl compositions of the SMA glasses as a function of frequency (6.5 Hz–65 kHz) and temperature (303–343 K), using the Solatron frequency-response analyser (model 1250). The bulk conductivity and the appropriate physical model (equivalent circuit) of the SMA glass were obtained from the impedance analysis. The a.c. conductivity was calculated for different Agl compositions of SMA glasses at various temperatures and the obtained a.c. conductivity results were analysed using Jonscher's Universal Law. The conduction mechanism for the highest conducting SMA glassy compound has been explained using the diffusion path model. 相似文献
49.
Wireless Personal Communications - Wireless Sensor Network plays a vital role and part of real time communication applications. Location of unknown node is difficult to find in the presence of... 相似文献
50.