NOPR Collection:

Thermo-mechanical properties of unsaturated polyester toughened epoxysiliconized iron (III) oxide nanocomposites

2014-05-13T11:42:21Z

Title: Thermo-mechanical properties of unsaturated polyester toughened epoxysiliconized iron (III) oxide nanocomposites Authors: Jaisingh, S Julyes; Selvam, V; Kumar, M Suresh Chandra; Thyagarajan, K Abstract: Novel siliconized iron (III) oxide nanoparticles reinforced unsaturated polyester (UP) toughened epoxy nanocomposites is prepared. The siliconized iron (III) oxide nanoparticles are improved thermal and mechanical properties of nanocomposites. Diglycidyl ether of bisphenol A (DGEBA) based epoxy resin is toughened with 5, 10 and 15% (by wt) of UP using benzoyl peroxide as radical initiator and 4, 4′ -diaminodiphenylmethane (DDM) as curing agent. UP toughened epoxy systems are reinforced with 1, 3, and 5% (by wt) of siliconized iron (III) oxide nanoparticles. The thermal and mechanical properties, and microstructures of nanocomposites are investigated. Data results from thermal and mechanical studies indicate that the insertion of siliconized iron (III) oxide nanoparticles into UP toughened epoxy system enhances the thermal and mechanical properties. Morphology of the hybrid system reveals homogenous distribution of nanoparticles. Page(s): 241-245

Reconfigurable architecture of RNS based high speed FIR filter

2014-05-22T18:15:20Z

Title: Reconfigurable architecture of RNS based high speed FIR filter Authors: Pari, J Britto; Rani, S P Joy Vasantha Abstract: In this paper, a high speed reconfigurable FIR filter with multiple taps using accumulator based radix-4 multiplier is proposed. The 3n-bit binary input is converted into three residues using binary to residue number system (RNS) converter and then processed in three FIR sub filters constructed in direct form. The filter structure is implemented with a multiply and accumulate (MAC) architecture using accumulator based radix-4 multiplier. The reconfigurable structure is achieved by combining power of two (PoT) FIR sub modules and the coefficients are altered during runtime. The proposed design is tested and implemented for 20-tap FIR filter. The architecture is implemented using VHDL and synthesized using Altera cyclone II EP2C35F672C6. The performance results show that the architecture achieves low power and high speed and variable tap flexibility. Page(s): 233-240

Fly ash based lightweight aggregates incorporating clay binders

2014-05-17T18:19:49Z

Title: Fly ash based lightweight aggregates incorporating clay binders Authors: Gomathi, P; Sivakumar, A Abstract: This study focuses on the strength characterization of artificial fly ash aggregates produced from a pelletization process. Additionally, to improve the stability and strength properties of fly ash aggregates clay binders such as bentonite and metakaolin are added during the production. Physical properties such as specific gravity, bulk density, water absorption, gradation and individual crushing strength of aggregates are determined. The faster hardening of fresh aggregates is envisaged with the addition alkali activator in the binder. Fly ash aggregates are then cured in different environmental conditions such as controlled humidity curing at 40% RH and 35ºC, hot air oven curing at two different temperatures - 50ºC and 100ºC. Porosity of fly ash aggregates is found to be reduced with the addition of binder material as a result of good agglomeration with fly ash. Also, the production efficiency of fly ash aggregates is found to be dependent on the binary blends of fly ash with clay binders and the concentration of alkali activator added to the fly ash. The test results also indicate that a maximum crushing strength of 17.97 MPa can be obtained in the case of fly ash aggregates subjected to hot air oven curing at 100ºC. Page(s): 227-232

Flexural behaviour of latex modified steel fiber reinforced concrete

2014-05-12T18:20:03Z

Title: Flexural behaviour of latex modified steel fiber reinforced concrete Authors: Meraj, Tarannum; Pandey, A K; Rao, B K Abstract: The flexural behaviour of plain concrete (PC), latex modified concrete (LMC) and latex modified steel fiber reinforced concrete (LMSFC) beams are studied under monotonic third point loading till ultimate stages. All the three types of concretes are designed for M-30 grade concrete. In LMC styrene butadiene latex 10% of cement weight is used. LMSFC concrete crimped steel fiber of aspect ratio of 16.67 at 1% of volume of concrete and SBR latex equal to 10% weight of cement are incorporated. An experimental program consisting of tests on latex modified concrete, latex modified steel fiber reinforced concrete and plain reinforced concrete are conducted under flexural loading. Beams are reinforced with bottom longitudinal steel bars and transverse steel stirrups. Tests on PC, LMC and LMSFC beam specimens have been conducted to establish load-deflection curves. The various parameters, such as stress-strain variation, first crack load, ultimate load, deflection ductility and strain variation along the depth of the beams have been carried out and a quantitative comparison are made at various stages of loading. It is found from this study that the neglect of fiber and latex contribution may considerably underestimate the flexural capacity of latex modified fiber-reinforced concrete beams. The present study also indicates that the ductility in LMC and LMSFC is increased by 45.94% and 50.27% respectively as compared to PC beams. Page(s): 219-226