Random Access Career Sense Protocol: A Comparative Analysis of Non Persistent and 1 Persistent CSMA

In this paper we discussed the simulation based comparative analysis of two random access carrier sense protocol ie. Non persistent CSMA and 1 persistent CSMA in wireless network taking considering of random back off algorithm. The feedback comparison of both protocols compared with respect to load on medium utilization and average waiting time. Both results are demonstrated in different load conditions

MAC IEEE802.11 CSMA/CA: A Simulative Performance Analysis

In this paper we introduce an algorithm based analytical model to calculate the performance of the wireless LAN MAC protocol – known as Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) – taking into consideration the random exponential back off algorithm. The effects of changing the load on medium utilization and average waiting time are demonstrated and result concluded for high medium and low load conditions

The size induced effect on rheological properties of Co-ferrite based ferrofluid

Finite size effect on structural, magnetic and rheological properties of Co-ferrite based ferrofluids has been investigated in detail. The shape and size distribution has been confirmed by transmission electron microscopy. The average particle size varies in the range 8 nm <= x <= 34 nm. The size induced rheological studies of ferrofluid with varying magnetic field and shear rate gives an insight to the work. The large size particles show less viscosity as compared to small size particles. Using H-B model, particle size dependent interaction with flow properties has been established. In addition, time dependent formation and destruction of magnetically induced structures has been described. The result of our investigations shows that the rheological measurements are in accordance with structural and magnetic properties of the ferrofluids

Tribological properties of silica-graphene nano-platelet composites

Graphene nano-platelets (GNP) were synthesised using a liquid phase exfoliation method and then used to produce well dispersed silica–GNP composites. The tribological properties of the silica–GNP composites with different vol% GNP loading were investigated. The wear behaviour at room temperature was studied using a ball on disc technique with alumina and borosilicate (BS) balls as the tribological counterpart. In the case of alumina balls, GNP above a critical concentration decreased the coefficient of friction of the composite by ~20% while increasing the wear resistance of the composite by ~5.5 times. In the case of using BS balls there was an improvement of ~8.5 times in the wear resistance while the coefficient of friction did not change. In both cases a percolating network of GNP above a critical concentration provided a lubricating effect to the silica matrix, resulting in a significant improvement in the tribological properties of the nano-composites. The extent of damage to GNP during tribology testing was quantified using Raman spectroscopy