NOPR Collection:

Effect of sintering temperature on densification and properties of T15-5wt% Cu steels containing Al₂O₃ particles

Thu, 01 Jun 2000 00:00:00 GMT

Title: Effect of sintering temperature on densification and properties of T15-5wt% Cu steels containing Al₂O₃ particles Authors: Majumdar, P; Upadhyaya, G S Abstract: In the present investigation, the sintering of T15 HSS (particle size range of 63-106 μm) with addition of copper and/orAl₂O₃ was examined. The results showed that the higher sintered density was obtained in case of liquid phase sintered T15 HSS. Presence of copper further increased densification due to its transient liquid phase sintering effect. Addition of Al₂O₃ particles decreased densification due to poor wettability and less particle rearrangement. The Vickers microhardness varied with densification. Addition of copper further increased microhardness due to solid solution strengthening effect. Microhardness of sintered steels dropped during liquid phase sintering because of relatively less carbide particle density. The magnetic coercivity variation was parallel to the hardness changes. Page(s): 141-149

Studies on energetic compounds (Part 12) - Preparation and thermolysis of transition metal salts of 5-nitro-2,4-dihydro-3H-1,2,4-triazole-3-one (NTO)

Thu, 01 Jun 2000 00:00:00 GMT

Title: Studies on energetic compounds (Part 12) - Preparation and thermolysis of transition metal salts of 5-nitro-2,4-dihydro-3H-1,2,4-triazole-3-one (NTO) Authors: Singh, Gurdip; Kapoor, Inder Pal Singh; Tiwari, Sunil Kumar; Prem Felix, S Abstract: Six new energetic transition metal salts of 5-nitro-2,4-dihydro-3H-1 ,2,4-triazole-3-one (NTO) were prepared and characterised. The thermal and explosive behaviour of these salts [M(NTO)₂, M=Mn, Fe, Co, Ni , Cu and Zn] were studied by TG, DSC and explosion delay measurements. It seems that explosive behaviour of NTO is quite enhanced due to the transition metal ions as these are reported to be very good oxidation catalysts. Thus, these salts may be explored as burning rate modifiers for solid propellants. Page(s): 167-171

Diethylene glycol acrylate-n-vinyl pyrrolidone copolymer resins for bone cement applications

Thu, 01 Jun 2000 00:00:00 GMT

Title: Diethylene glycol acrylate-n-vinyl pyrrolidone copolymer resins for bone cement applications Authors: Celin, D; Thomas, Vinoy; Jayabalan, Muthu Abstract: Biodegradable and injectable monomer diethylene glycol acrylate (DGA) and diethylene glycol acrylate-n -vinyl pyrrolidone (DGA-VP) blends have been prepared and evaluated their suitability for bone cement applications. Studies on the setting of the monomer DGA and the blend DGA-VP have been carried out using a free radical initiator. Lower setting time is observed with the monomer in comparison with that of the blend. The degradation of cured PDGA and P(DGA- VP) polymeric materials has been evaluated in simulated physiological fluids. Studies on degradation in hydrolytic and oxidative media reveal faster degradation during initial period of aging followed by slower and steady state degradation. In vitro degradation studies show more hydrolytic degradation in PDGA while both hydrolytic and oxidative degradation in P(DGA-VP) in comparison to that of PDGA. Also, the biocompatible comonomer (VP) enhances biodegradation of aliphatic polyester PDGA. Page(s): 160-166

Pozzolanic action of Homra with lime

Thu, 01 Jun 2000 00:00:00 GMT

Title: Pozzolanic action of Homra with lime Authors: Heikal, M; El-Didamony, H; Ali, A H Abstract: Pozzolanic activity of fired clay bricks (Homra) was studied using hydrated lime as an activator. Three different mixes of Homra/hydrated lime were hydrated in a paste form for various time intervals up to 90 days. The hydration characteristics of the hydrated pastes were followed by thermal analysis (TGA and DTA) at various times of hydration. The results obtained from thermal analysis of the formed hydrates were related as much as possible to the pozzolanic activity as determined by chemical analysis. The results indicated that Homra, as a waste product of clay bricks industry, can be used in the production of low cost filled pozzolanic cements. Page(s): 154-159

NOPR Collection:

Effect of sintering temperature on densification and properties of T15-5wt% Cu steels containing Al2O3 particles

Studies on energetic compounds (Part 12) - Preparation and thermolysis of transition metal salts of 5-nitro-2,4-dihydro-3H-1,2,4-triazole-3-one (NTO)

Diethylene glycol acrylate-n-vinyl pyrrolidone copolymer resins for bone cement applications

Pozzolanic action of Homra with lime

Effect of sintering temperature on densification and properties of T15-5wt% Cu steels containing Al₂O₃ particles