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71.
A. K. Lakshminarayanan V. Balasubramanian R. Varahamoorthy S. Babu 《Metals and Materials International》2008,14(6):779-789
Control of dilution is important in hardfacing, where low dilution is typically desirable. At present, most fabrication industries
use shielded metal are welding, gas metal arc welding, gas tungsten arc welding and submerged are welding processes for hardfacing
purposes. In these processes, the percentage of the dilution level is higher, ranging between 10% and 30%. In Plasma Transferred
Arc (PTA) hardfacing, a solidified metallurgical bond between the deposit and the substrate is obtained with minimum dilution
(less than 10%). This paper highlights the application of response surface methodology to predict and optimize the percentage
of the dilution of a cobalt-based hardfaced surface produced by the PTA process. Experiments were conducted based on a fully
replicable five-factor, five-level central composite rotatable design and a mathematical model was developed using response
surface methodology. Furthermore, the response surface methodology was used to optimize the process parameters that yield
the lowest percentage of dilution. 相似文献
72.
73.
Contents of various elements in dyferent parts of the tea plant (shoot, mature leaf, small stem, thick wood and root), black tea manufactured by the crush-tear-curl and orthodox processes, and tea brew after 1 and 5 min of infusion were determined by inductively coupled plasma atomic emission spectrometry. From these, the amount of each element assimilated in the production of 1000 kg of marketable tea, as well as the quantity of each element brought into infusion and thus possib f y taken up through drinking tea, were calculated and discussed. Among the various elements assimilated by the tea plant, the shoot jraction (economically important for manufacturing commercial tea) contained high concentrations of N, P, K and Mg while the mature leaf accumulated Al, Bu, Ca, Cd, Mn, Pb and Sr. Of the dgerent elements brought into infusion while brewing black tea, the amount of K was found to be the largest (> 10000 μg g−1 tea) followed by P (700–1200 μg g−1), Mg (300–700 μg g−1), Ca and A1 (each 150–300 μg−1), Mn (60–150 μg g−1), Cu, Na, Si and Z n (each 6–50 μg g−1), B, Ba, Cr, Fe, Ni and Pb (each Id μg g−1), and Sr, Co and Gd (each <1μg g−1). The proportion of the totalamount of an element brought into infusion showed that the elements Ba, Ca, Fe and Sr were less soluble (<10 % of total amount), Al, B, Cd, Co, Cr, Cu, Mg, Mn, P, Pb, Si and Zn were moderately soluble (10–50 %), and K, Nu and Ni were highly soluble (>50%). The overall mean of the extent of solubility of all elements in 1 and 5 min showed that, out of the amount soluble in 5 min, about 68% was dissolved within 1 min. 相似文献
74.
Z. Zeng K. Natesan Z. Cai D. Gosztola R. Cook J. Hiller 《Journal of Materials Engineering and Performance》2014,23(4):1247-1262
A detailed study was conducted on localized oxidation on Type 321 stainless steel (321ss) using synchrotron x-ray nanobeam analysis along with Raman microscopy. The results showed the presence of metallic nanonetworks in the oxide scales, which plays an important role in the continued oxidation of the alloy at 750 °C. A mechanism is proposed to explain the rapid oxidation of 321ss in complex gaseous environments at elevated temperature. Neutral metal atoms could diffuse outward, and carbon atoms could diffuse inward through the metallic nanonetworks in oxide layers. Alternately, diffusion tunnels can dramatically affect the phase composition of the oxide scales. Since the diffusion rate of neutral metal and carbon atoms through the metallic nanonetworks can be much faster than the diffusion of cations through Cr2O3, the metallic nanonetwork provides a path through the protective Cr2O3 layer for the rapid outward diffusion of metallic chromium and iron atoms to the nonprotective spinel layer. This diffusion process affects the solid-state reaction near the alloy-oxide boundary, and a dense Cr2O3 protective layer does not form. The classic stable structure of the oxide scales, with a dense Cr2O3 layer at the bottom, is damaged by the rapid diffusion through the tunnel at the reaction front, resulting in locally accelerated oxidation. This process can subsequently lead to “breakaway” oxidation and catastrophic failure of the alloy. 相似文献
75.
C. Thiruvikraman V. Balasubramanian K. Sridhar 《Journal of Thermal Spray Technology》2014,23(5):860-875
High velocity oxygen fuel (HVOF)-sprayed cermet coatings are extensively used to combat erosion-corrosion in naval applications and in slurry environments. HVOF spray parameters such as oxygen flow rate, fuel flow rate, powder feed rate, carrier gas flow rate, and spray distance have significant influence on coating characteristics like adhesion bond strength and shear strength. This paper presents the use of statistical techniques in particular response surface methodology (RSM), analysis of variance, and regression analysis to develop empirical relationships to predict adhesion bond strength and lap shear bond strength of HVOF-sprayed WC-CrC-Ni coatings. The developed empirical relationships can be effectively used to predict adhesion bond strength and lap shear bond strength of HVOF-sprayed WC-CrC-Ni coatings at 95% confidence level. Response graphs and contour plots were constructed to identify the optimum HVOF spray parameters to attain maximum bond strength in WC-CrC-Ni coatings. 相似文献
76.
V. Malathy S. Sivaranjani V. S. Vidhya T. Balasubramanian J. Joseph Prince C. Sanjeeviraja M. Jayachandran 《Journal of Materials Science: Materials in Electronics》2010,21(12):1299-1307
RF sputtering process has been used to deposit highly transparent and conducting films of tin-doped indium oxide onto quartz
substrates keeping the RF power constant at 250 W. The electrical, optical and structural properties have been investigated
as a function of substrate temperature. XRD has shown that deposited films are polycrystalline and have (400) preferred orientation.
Indium tin oxide layers with low resistivity values and high transmittance in the visible region have been deposited. Detailed
Analyses based on X-ray diffraction, optical and electrical results are attempted to gain more insight into the factors that
are governed by the influence of varying substrate temperature in this investigation. AFM pictures showed uniform surface
morphology with very low surface roughness values. It has been observed that ITO films deposited in this study, keeping the
substrate temperature at 150 °C, can provide the required optimum electrical and optical properties rendering them useful
for developing many optoelectronic devices at a moderate temperature. 相似文献
77.
L. Satish Kumar K. Natesan A. John Arul V. Balasubramaniyan S.C. Chetal 《Nuclear Engineering and Design》2011,241(12):4953-4959
The decay heat removal (DHR) system removes the decay heat generated (by radioactive decay of fission products) in the core after the reactor is shut down, thereby ensuring proper cooling of the core sub assemblies and limiting main vessel, internals and sodium temperature within safe limits. There are two diverse paths for removal of decay heat from the reactor, namely, Safety Grade Decay Heat Removal System (SGDHRS) and Operation Grade Decay Heat Removal System (OGDHRS). OGDHR circuit is used when at least one secondary sodium loop, DHR related steam water circuit and off site power supply is available and SGDHR circuit is used when OGDHR system is not available or when both the secondary loops are not available for DHR. This paper provides brief details of the design and evaluation of OGDHRS. 相似文献
78.
79.
Anti‐obesity action of gingerol: effect on lipid profile,insulin, leptin,amylase and lipase in male obese rats induced by a high‐fat diet
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80.
Aluminium alloy matrix composites with carbon fibre reinforcement were prepared by stir casting method. In order to avoid any interfacial reactions in the carbon fibre reinforced composites, the carbon fibres were coated with copper. The fibres were coated by electroless coating method and then characterized. Composites containing different amounts of carbon fibres were prepared by stir casting and then subjected to age-hardening treatment. Fibre distribution was fairly uniform in the composites containing up to 4 wt% carbon fibres. Tensile strength of the composites was found to be increasing up to 4 wt% carbon fibre. 相似文献