http://nopr.niscair.res.in/handle/123456789/6031 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/6043 Title: Preparation and characterization of nickel doped, A and B Site LaCoO3 perovskite <br/> <br/>Authors: Singh, Chandrakant; Rakesh, Meeta <br/> <br/>Abstract: This paper presents an approach to the preparation of LaCoO₃perovskite and nickel doped LaCoO₃ in A and B site both, to see the effect of nickel doping in both the site catalyst synthesized by co-precipitation method. The novelty of the experiment is nickel doped in A-site of LaCoO₃perovskite to see effect of nickel doping into their physical properties (i.e. crystalline phase and microstructure). Samples have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Branauer–Emmett-Teller (BET) nitrogen adsorption technique <br/> <br/>Page(s): 288-290 http://nopr.niscair.res.in/handle/123456789/6042 Title: Nanostructured silver-graphite electrical contact materials processed by mechanical milling <br/> <br/>Authors: Rehani, Bharati R; Joshi, P B; Kaushik, V K <br/> <br/>Abstract: In last few decades there has been a growing interest in nanostructured materials in view of their improved mechanical, physical and chemical properties. A wide variety of techniques have been developed to synthesize nanopowders including high-energy milling or mechanical alloying (MA) for producing bulk nanostructures. High-energy milling is used for preparation of elemental and composite powders of different metals and non-metals. Literature reports the synthesis of ductile-ductile composites such as aluminium-graphite and copper-graphite by MA owing to its potential benefits in terms of improved mechanical properties. Reports are also there on the application of this technology for processing of silver-graphite contact materials offering improved switching properties. The present investigation deals with a comparative study on synthesis of silver-graphite nanocomposite powders in a planetary ball mill using two different approaches, namely milling of a blend of silver and graphite powder particles in one case and milling of only elemental silver powder in the other. The study revealed that somewhat inferior properties are obtained for the AgC bulk solids prepared from powders synthesized by the former approach. This is in view of the tendency of graphite to coat silver during milling, leading to very poor silver-silver interparticle contacts and resultant bulk solid with high porosity. However, an alternative approach of milling silver alone in the planetary mill is found to offer not only improved properties but also reduction in sintering temperature. <br/> <br/>Page(s): 281-287 http://nopr.niscair.res.in/handle/123456789/6041 Title: Simple fabrication of Mg2Si thermoelectric generator by spark plasma sintering <br/> <br/>Authors: Yang, M J; Zhang, L M; Han, L Q; Shen, Q; Wang, C B <br/> <br/>Abstract: Raw Mg and Si<b style=""> </b>powders<b style=""> </b>have been used to fabricate Mg₂Si bulk thermoelectric generator by spark plasma sintering (SPS).<b style=""> </b>The<b style=""> </b>optimum parameters to synthesize pure Mg₂Si are found to be 823 K-0 MPa-10 min with excessive content of 10wt% Mg from the stoichiometric Mg₂Si. Mg₂Si bulk has been firstly synthesized and densified simultaneously at low temperature (823 K) and high pressure (higher than 100 MPa) from the raw powder, but Mg and Si not react completely, and the sample is not very dense with some microcracks on the surface. Then, Mg and Si powders firstly reacted at 823 K-0 MPa-10 min in SPS chamber to form Mg₂Si green compact, again sintered by SPS at 1023 K-20 MPa-5 min. The fabricated sample only contained Mg₂Si phase with high relative density (nearly 100%). <br/> <br/>Page(s): 277-280 http://nopr.niscair.res.in/handle/123456789/6039 Title: Use of lime cement stabilized pavement construction <br/> <br/>Authors: Kumar, M Anjan; Raju, G V R Prasada <br/> <br/>Abstract: <smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="country-region"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"> Expansive clay is a major source of heave induced structural distress. Swelling of expansive soils causes serious problems and produce damages to many structures. Many research organizations are doing extensive work on waste materials concerning the feasibility and environmental suitability. Fly ash, a waste by product from coal burning in thermal power stations is abundant in India causing severe health, environmental and disposal problems. Attempts are made to investigate the stabilization process with model test tracks over expansive subgrade in flexible pavements. Cyclic plate load tests are carried out on the tracks with chemicals like lime and cement introduced in fly ash subbase laid on sand and expansive subgrades. Test results show that maximum load carrying capacity is obtained for stabilized fly ash subbase compared to untreated fly ash subbase</smarttagtype></smarttagtype> <br/> <br/>Page(s): 269-276