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651.
Ibram Ganesh Susana M. Olhero Paula M.C. Torres Fernando J. Alves José M.F. Ferreira 《Journal of the European Ceramic Society》2009,29(8):1393-1401
A new near-net shape forming process called “hydrolysis-induced aqueous gelcasting” (GCHAS) is reported in this paper for the consolidation of ZTA composites, ZTA-30 (70 wt.% Al2O3 + 30 wt.% ZrO2) and ZTA-60 (40 wt.% Al2O3 + 60 wt.% ZrO2). For comparison purposes, ceramics having the same chemical compositions were also consolidated by hydrolysis-assisted solidification (HAS). All the starting suspensions contained a solids loading of 50 vol.%. In the precursor powder mixtures, 1–5 wt.% of Al2O3 was replaced by equivalent amounts of AlN to enhance or promote or co-promote the consolidation of suspensions by HAS or by GCHAS, respectively. The suspensions for GCHAS were prepared by dispersing the ZTA powder precursor mixtures in a premix solution of 20 wt.% MAM (methacrylamide), MBAM (methylenebisacrylamide) and NVP (n-vinylpyrrolidinone) in 3:1:3 ratio in de-ionized water. Ceramics consolidated via GCHAS exhibited superior mechanical properties after consolidation and after sintering for 1 h at 1600 °C in comparison to those consolidated by HAS. 相似文献
652.
Properties of lightweight expanded polystyrene aggregate concretes containing fly ash 总被引:3,自引:0,他引:3
Lightweight concretes can be produced by replacing the normal aggregates in concrete or mortar either partially or fully, depending upon the requirements of density and strength levels. The present study covers the use of expanded polystyrene (EPS) beads as lightweight aggregate, both in concrete and mortar. The main aim of this programme is to study the mechanical properties of EPS concretes containing fly ash and compare the results with these in literature on concretes containing OPC alone as the binder. The effects of EPS aggregate on the green and hardened state characteristics of concretes containing fly ash were evaluated. The compressive strength of the EPS concretes containing fly ash show a continuous gain even up to 90 days, unlike that reported for OPC in literature. It was also found that the failure of these concretes both in compression and split tension was gradual as was observed earlier for the concretes containing plastic shredded aggregates. The stress-strain relations and the corresponding elastic modulus were also investigated. 相似文献
653.
654.
P. Ganesh R. Kaul S. Mishra P. Bhargava C. P. Paul Ch. Prem Singh P. Tiwari S. M. Oak R. C. Prasad 《Transactions of the Indian Institute of Metals》2009,62(2):169-174
Fabrication of multi-material engineering components is one of the technologies to address diverse and conflicting functional
requirements posed by rapid technological development. Bi-metallic tube is one such multi-material component with different
materials on internal and outer surfaces. This paper briefs about fabrication of a bi-metallic tubular structure with an indigenously
developed 3.5 kW CO2 laser integrated with a beam delivery system, a 5-axis CNC work station along with a powder feeding sub-system. The bi-metallic
tube was fabricated with cobalt based alloy Stellite 21 on inner diameter and type 316L stainless steel on the outer diameter.
Besides, a stainless steel tube with an internal step of Stellite 21 was also fabricated. As-fabricated bi-metallic structure
was structurally sound and carried desired transition in chemical composition and hardness across its wall thickness. 相似文献
655.
S. Raju B. Jeya Ganesh Arun Kumar Rai R. Mythili S. Saroja E. Mohandas M. Vijayalakshmi K.B.S. Rao Baldev Raj 《Journal of Nuclear Materials》2009,389(3):385-393
The on-heating phase transformation temperatures up to the melting regime and the specific heat capacity of a reduced activation ferritic-martensitic steel (RAFM) with a nominal composition (wt%): 9Cr-0.09C-0.56Mn-0.23V-1W-0.063Ta-0.02N, have been measured using high temperature differential scanning calorimetry. The α-ferrite + carbides → γ-austenite transformation start and finish temperatures, namely Ac1, and Ac3, are found to be 1104 and 1144 K, respectively for a typical normalized and tempered microstructure. It is also observed that the martensite start (MS) and finish (Mf) temperatures are sensitive to the austenitising conditions. Typical MS and Mf values for the 1273 K normalized and 1033 K tempered samples are of the order 714 and 614 K, respectively. The heat capacity CP of the RAFM steel has been measured in the temperature range 473-1273 K, for different normalized and tempered samples. In essence, it is found that the CP of the fully martensitic microstructure is found to be lower than that of its tempered counterpart, and this difference begins to increase in an appreciable manner from about 800 K. The heat capacity of the normalized microstructure is found to vary from 480 to 500 J kg−1 K−1 at 500 K, where as that of the tempered steel is found to be higher by about, 150 J kg−1 K−1. 相似文献
656.
Dechlorination of trichloroethylene by Ni/Fe nanoparticles immobilized in PEG/PVDF and PEG/nylon 66 membranes 总被引:2,自引:0,他引:2
Ganesh K. Parshetti 《Water research》2009,43(12):3086-3094
The highly reactive bimetallic Fe/Ni nanoparticles immobilized in nylon 66 and PVDF membranes were synthesized and characterized for dechlorination of trichloroethylene (TCE) under anoxic conditions. Scanning electron microscopy (SEM) images and electron probe microanalysis (EPMA) elemental maps showed that the distribution of Fe in nylon 66 membrane was uniform and the intensity of Ni layer was higher than that in PVDF membrane. The particle sizes of bimetallic Fe/Ni in PVDF and nylon 66 membranes were 81 ± 12 and 55 ± 14 nm with the Ni layers of 12 ± 3 and 15 ± 2 nm, respectively. Low agglomeration of immobilized Fe/Ni nanoparticles in nylon 66 membrane was observed, presumably attributed to the more multifunctional chelating groups in membrane. A rapid hydrodechlorination of TCE with ethane as the main end product was observed by the immobilized Fe/Ni nanoparticles. The pseudo-first-order rate constants for TCE dechlorination were 6.44 ± 0.32 and 1.66 ± 0.08 h−1 for nylon 66 and PVDF membranes, respectively. In addition, the efficiency and rate of TCE dechlorination increased upon increasing the mass loading of Ni, ranging between 2.5 and 20 wt%, and then decreased when further increased the Ni loading to 25 wt%. In addition, the stability and longevity of the immobilized Fe/Ni nanoparticles was evaluated by repeatedly injecting TCE into the solutions. A rapid and complete dechlorination of TCE by trace amounts of Fe/Ni nanoparticles was observed after 16 cycles of injection within 10 days, indicating that the immobilization of Fe/Ni nanoparticles in the hydrophilic nylon 66 membrane can retain the longevity and high reactivity of nanoparticles towards TCE dechlorination. 相似文献
657.
Sangappa S. Asha Ganesh Sanjeev R. Somashekar 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(14):2385-2389
Radiation-induced changes in hydroxypropyl methylcellulose (HPMC) films under electron irradiation were investigated and correlated with dose. Polymer samples were irradiated in air at room temperature by an electron beam accelerator in the range of 0-100 kGy. Various properties of the irradiated films were studied using a Ultraviolet-Visible spectrophotometer and Fourier transform infrared spectroscopy and thermogravimetric analysis. Electron irradiation was found to induce changes in the physical, chemical and thermal properties, depending on the irradiation dose. 相似文献
658.
Satendra Kumar T.S.N. Sankara Narayanan S. Ganesh Sundara Raman S.K. Seshadri 《Materials science & engineering. C, Materials for biological applications》2009,29(6):1942-1949
Commercially pure titanium (CP-Ti) samples were subjected to thermal oxidation (TO) treatment at 650 °C for 8, 16, 24 and 48 h. The morphological features, structural characteristics, microhardness and corrosion resistance in Ringer's solution of thermally oxidized samples were compared with that of the untreated one, to ascertain the suitability of thermally oxidized sample as a bio-implant. The thickness, morphological features and phase constituents of the oxide film formed during thermal oxidation (TO) exhibit a strong dependence on the treatment time. Samples oxidized for 48 h lead to the formation of oxide grains along with a thick oxide film consisting of rutile and TiO phase. Samples oxidized for 24 h lead to the formation of oxide grains with thinner oxide layer at the grain boundary. Almost a 3 fold increase in hardness is observed for samples oxidized for 48 h compared to that of the untreated sample. Based on the corrosion protective ability, the untreated and thermally oxidized samples can be ranked as follows: {TO 48 h} > {TO 16 h} > {TO 8 h} ≈ {TO 24 h} > untreated. From corrosion protection point of view, TO for 48 h is a promising surface treatment and it can be a suitable alternative to the untreated CP-Ti as a bio-implant. 相似文献
659.
DataFoundry: information management for scientific data 总被引:3,自引:0,他引:3
Critchlow T. Fidelis K. Ganesh M. Musick R. Slezak T. 《IEEE transactions on information technology in biomedicine》2000,4(1):52-57
Data warehouses and data marts have been successfully applied to a multitude of commercial business applications. They have proven to be invaluable tools by integrating information from distributed, heterogeneous sources and summarizing this data for use throughout the enterprise. Although the need for information dissemination is as vital in science as in business, working warehouses in this community are scarce because traditional warehousing techniques do not transfer to scientific environments. There are two primary reasons for this difficulty. First, schema integration is more difficult for scientific databases than for business sources because of the complexity of the concepts and the associated relationships. Second, scientific data sources have highly dynamic data representations (schemata). When a data source participating in a warehouse changes its schema, both the mediator transferring data to the warehouse and the warehouse itself need to be updated to reflect these modifications. The cost of repeatedly performing these updates in a traditional warehouse, as is required in a dynamic environment, is prohibitive. The paper discusses these issues within the context of the DataFoundry project, an ongoing research effort at Lawrence Livermore National Laboratory. DataFoundry utilizes a unique integration strategy to identify corresponding instances while maintaining differences between data from different sources, and a novel architecture and an extensive meta-data infrastructure, which reduce the cost of maintaining a warehouse 相似文献
660.
Sangappa T. Demappa Mahadevaiah S. Ganesh S. Divakara R. Somashekar 《应用聚合物科学杂志》2008,109(6):3983-3990
The changes in microstructural parameters in hydroxypropyl methylcellulose (HPMC) polymer films irradiated with 8 MeV electron beam have been studied using wide‐angle X‐ray scattering (WAXS) method. The crystal imperfection parameters such as crystal size <N>, lattice strain (g in %), and enthalpy (α*) have been determined by line profile analysis (LPA) using Fourier method of Warren. Exponential, Lognormal, and Reinhold functions for the column length distributions have been used for the determination of these parameters. The goodness of the fit and the consistency of these results suggest that the exponential distribution gives much better results, even though lognormal distribution has been widely used to estimate the similar stacking faults in metal oxide compounds. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献