http://dspace.daffodilvarsity.edu.bd:8080/handle/123456789/11314 2026-04-05T17:28:56Z 2026-04-05T17:28:56Z Islam, MD. Zahirul http://dspace.daffodilvarsity.edu.bd:8080/handle/123456789/11351 2023-12-28T21:00:45Z 2014-07-01T00:00:00Z

Comparative Performance Analysis Between IEEE 802.11 Dcf and Proposed Coopmac+ Islam, MD. Zahirul Medium Access Control (MAC) protocol is used to ensure that signals from different stations across the same channel collide. In this paper, a novel idea of user cooperation in wireless networks has been exploited to improve the performance of the IEEE 802.11 medium access control (MAC) protocol. The new MAC protocol leverages the multi-rate capability of IEEE 802.11b and allows the mobile stations (STA) far away from the access point (AP) to transmit at a higher rate by using an intermediate station as a relay. CoopMAC protocol is able to increase the throughput of the whole network and reduce the average packet delay. Moreover, CoopMAC also maintains backward compatibility with the legacy 802.11 protocol. The performance improvement is further evaluated by analysis and extensive simulations.

2014-07-01T00:00:00Z Ayoola, Wasiu Ajibola Oyetunji, Akinlabi http://dspace.daffodilvarsity.edu.bd:8080/handle/123456789/11350 2023-12-28T21:00:45Z 2014-07-01T00:00:00Z

Effect of Deformation and Annealing Processing on Texture and Mechanical Properties of Aluminum Alloy AA1200 Ayoola, Wasiu Ajibola; Oyetunji, Akinlabi The tensile strength, hardness, percentage elongation and grain size characteristics of aluminum alloy AA1200 were studied. The alloy samples were cold rolled prior to these tests with strain between 78 93, and thereafter annealed at temperatures lying between 200-450 "C and at holding times of between 2-6 hours. The results obtained showed that both the Ultimate Tensile Strength (UTS) and hardness increased with a higher degree of deformation prior to testing, but decreased as the annealing temperatures increased. The grain diameters on the other hand were seen to increase with increasing prior deformations and these fluctuate between 22.4 to 45 μm with an increase in the annealing temperatures.

2014-07-01T00:00:00Z Oyetunji, A. Omole, S.O. http://dspace.daffodilvarsity.edu.bd:8080/handle/123456789/11349 2023-12-28T21:00:45Z 2014-07-01T00:00:00Z

Achievement of Nodules in Ductile Iron Having Sulphur Content Not Less Than 0.07% Weight Oyetunji, A.; Omole, S.O. Scraps melt were analyzed with optical light emission spectrometer for chemical composition. The charge was prepared theoretically with carbon percent of 3.9 and silicon of between 2.1 and 2.8 percent after inoculation. 2 kg of CaCO3 (flux) was charged to aid removal of slag. The charges were heated to a tapping temperature of 1430° C. Temperature was monitored by inserting thermocouple in to the charges. The melt was desulphurised with 0.30 kg calcium carbide (CaC2) after the attainment of 1430°C. Three tappings were made tagged A, B and C into the prepared ladle via sandwich process. 3.5 %, 3.0 % and 2.0 % of ladle capacity (15 Kg) was the quantity of Mg used to treat melts A, B and C respectively. The treated melts were poured into the prepared sand moulds forming desired casting. The as-cast were analyzed again to determine its chemical compositions and found that carbon and silicon were not less than 2.0 and 1.0 % respectively. The casting was tested for hardness, tensile and micro structural evaluation. The microstructures revealed that as-cast tagged A and B formed nodular iron when etched with 2 % nital even with residual sulphur content of 0.075 % and 0.070% for A and B respectively. Cast produced from melt C revealed not a clear nodular cast iron. Emphasis is on casting A and B as we obtained nodules in A and B.

2014-07-01T00:00:00Z Iqbal, MD. Asib Chowdhury, Dr. Nazmina Jubayer, MD. Minhajj Uddin Molla, Jannatul Bake Hossain, S.M. Mahruf http://dspace.daffodilvarsity.edu.bd:8080/handle/123456789/11348 2024-09-14T09:20:51Z 2014-07-01T00:00:00Z

Effect of Optical Brightening Agent on Different Types of Fabrics Iqbal, MD. Asib; Chowdhury, Dr. Nazmina; Jubayer, MD. Minhajj Uddin; Molla, Jannatul Bake; Hossain, S.M. Mahruf The knitted fabrics (single jersey, lycra single jersey, rib interlock, polo pique) were dyed with Optical Brightening Agent. From the overall comparison for different Shade% of different fabrics of Optical Brightening Agent, It was found that Color Index & Shade of Optical Brightening Agent is the most suitable dyeing used in industrial production. Optical Brightening Agent dyeing is probably the best described as an industrial art, having an assured future.

2014-07-01T00:00:00Z