http://nopr.niscair.res.in/handle/123456789/7203 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/7220 Title: Effect of additives on Al₂O₃ based LPG sensors <br/> <br/>Authors: Chaudhari, G N; Padole, P R; Patil, S S; Khandekar, U S; Sapkal, V S; Manorama, S V <br/> <br/>Abstract: <smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="State"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"> Sensitivity and selectivity of Al₂O₃ thick films for LPG gas sensor have been examined. The structural properties of Al₂O₃have been examined by means of XRD and the surface morphology by the SEM studies. XRD confirmed the complete phase formation at 800^oC for 6 h. The sensing properties and response time of (1 wt%) Pd:(10 wt%) Cr₂O₃ doped Al₂O₃ have been characterized by d.c. electrical measurements for different gases. The element is exposed to several gases such as LPG, CO, CH₄ in dry air. It shows good sensitivity and selectivity towards LPG at low operating temperature. </smarttagtype></smarttagtype> <br/> <br/>Page(s): 87-90 http://nopr.niscair.res.in/handle/123456789/7219 Title: Synthesis, characterization and thermolysis of polynitrohexahydropyrimidines: Potential high energy materials <br/> <br/>Authors: Jadhav, H S; Talawar, M B; Sivabalan, R; Dhavale, D D; Asthana, S N; Krishnamurthy, V N <br/> <br/>Abstract: A relatively new entrant to the class of high energy materials, viz., 1,3,5-trinitro-5-methyl-hexahydropyrimidine (MTNP)<b style=""> </b>has been synthesized during this work by nitration of 1,3-di-tert-butyl-5-nitro-5-methyl hexahydropyrimidine with fuming nitric acid. The synthesized molecule (MTNP)<b style=""> </b>has been characterized by elemental analysis, IR, ¹H and ¹³C NMR spectroscopy. TG of the compound showed two-step decomposition in the temperature range of 170-200°C and 205-350°C accompanied with 50 and 25% weight loss, respectively. The sensitivity data of MTNP obtained for the synthesized compound indicates its low vulnerability towards external stimuli (impact height, <i style="">h</i>_50% > 100 cm and friction insensitive up to 36 kg). The velocity of detonation of MTNP has been computed using Linear Output Thermodynamic User-friendly Software for Energetic Systems (LOTUSES) code. The theoretically computed VOD of 7450 m/s is intermediate to that of 2,4,6-trinitrotoluene, TNT (6600 m/s) and 1,3,5-triamino-2,4,6-trinitrobenzene, TATB (7860 m/s) coupled with insensitive nature are attractive features from the point of view of its applications in insensitive munitions. In addition to compound MTNP, synthesis and characterization of some of the promising polynitrohexahydropyrimidines have also been reported. <br/> <br/>Page(s): 80-86 http://nopr.niscair.res.in/handle/123456789/7218 Title: Strength and durability of cementitious binder produced from fly ash–lime sludge–Portland cement <br/> <br/>Authors: Garg, Mridul; Singh, Manjit <br/> <br/>Abstract: In this paper, investigations have been undertaken to produce cementitious binders by blending 60-70% fly ash with calcined phosphogypsum, hydrated lime sludge, Portland cement and chemical activator in different proportions. The results show that strength development of binders takes place through formation of ettringite, C-S-H and wollastonite. The durability of cementitious binder has been studied by its performance in water and by accelerated aging, i.e., alternate wetting and drying as well as by heating and cooling cycles at temperatures from 27to 50^oC. The results indicate that the strength of the binder decreased with increasing cyclic studies at different temperatures. The maximum fall in compressive strength has been noted at 50^oC. <br/> <br/>Page(s): 75-79 http://nopr.niscair.res.in/handle/123456789/7217 Title: Influence of titanium ionson dielectric and other physical properties of AF-PbO-B₂O₃ glasses <br/> <br/>Authors: Rao, P Nageswara; Rao, D Krishna; Veeraiah, N <br/> <br/>Abstract: Dielectric properties, viz., dielectric constant, <img src='/image/spc_char/italics_e.gif' border=0>, loss, tan <img src='/image/spc_char/delta1.gif' border=0>, a.c. conductivity, σ, in the frequency range 10²-10⁶ Hz and in the temperature range 30-300^oC and the dielectric breakdown strength in air of AF-PbO-B₂O_{3<b style=""> </b>}(A =Li, Na, K) glassescontaining different concentrations of TiO₂ (in the range 0-0.6 mol %) have been investigated. Results have been analyzed in the light of different oxidation states of titanium ions in the glass matrix with the aid of data on optical absorption, ESR and IR spectral studies. <br/> <br/>Page(s): 69-74