Investigation of Impact Energy Absorption of AA6061 and Composites: Role of Post-Aging Cooling Methods

Al6061 and its composites are widely employed in applications requiring high strength and impact resistance. Heat treatment, particularly ageing, is a well-established method for enhancing the mechanical properties of these composites. However, the influence of post-ageing cooling methods on the impact energy absorption capacity of Al6061 and its composites remains inadequately understood. This investigation aims to examine the impact energy absorption of Al6061 and its composites after ageing at 460°C for 2 hours, employing different cooling methods, including furnace cooling, air cooling, and water cooling. The composites were produced using the stir casting technique with varying weight fractions of graphite and SiC particles based on Taguchi's design of experiments. Charpy impact tests were conducted using a specialised testing machine. The results reveal that the impact energy absorption capacity of the composites is influenced by the cooling method employed after the ageing treatment. Furnace cooling demonstrated the highest impact energy absorption capacity compared to the other cooling methods, exhibiting a 28% increase compared to the monolithic aluminium alloy. Furthermore, it was observed that the impact energy absorption capacity of the composites did not improve with an increase in the weight fraction of SiC particles, while the addition of graphite negatively impacted the absorption capacity

Investigation of Impact Energy Absorption of AA6061 and Composites: Role of Post-Aging Cooling Methods

Al6061 and its composites are widely employed in applications requiring high strength and impact resistance. Heat treatment, particularly ageing, is a well-established method for enhancing the mechanical properties of these composites. However, the influence of post-ageing cooling methods on the impact energy absorption capacity of Al6061 and its composites remains inadequately understood. This investigation aims to examine the impact energy absorption of Al6061 and its composites after ageing at 460°C for 2 hours, employing different cooling methods, including furnace cooling, air cooling, and water cooling. The composites were produced using the stir casting technique with varying weight fractions of graphite and SiC particles based on Taguchi's design of experiments. Charpy impact tests were conducted using a specialised testing machine. The results reveal that the impact energy absorption capacity of the composites is influenced by the cooling method employed after the ageing treatment. Furnace cooling demonstrated the highest impact energy absorption capacity compared to the other cooling methods, exhibiting a 28% increase compared to the monolithic aluminium alloy. Furthermore, it was observed that the impact energy absorption capacity of the composites did not improve with an increase in the weight fraction of SiC particles, while the addition of graphite negatively impacted the absorption capacity

RESPONSE OF BOLLWORMS AGAINST TRANSGENIC Bt COTTON IN THE CENTRAL TELANGANA AGRO CLIMATIC ZONE OF ANDHRA PRADESH

Studies on population dynamics of boll worms on transgenic Bt cotton viz. American bollworm, also called false America bollworm or old world bollworm, Helicoverpa armigera (Hubner). pink bollworm, Pectinophora gossypiella (Saunders), and the leaf worm, Spodoptera litura (Fabr.) is mainly a foliage feeder but it also damages cotton bolls were carried out in the farmers fields under unprotected conditions in the Central Telangana agro climatic Zone of Andhra Pradesh during 2010-11 Kharif season. The incidence of bollworms began 100 Days after sowing. The moderate incidence of Spodoptera litura was recorded (0.02 to 3.2 larvae Plant). Low level of Pectinophora gossypiella (0.01 to 0.092 larvae plant) and very low level of Helicoverpa armigera as recorded (0.002 to 0.17 larvae plant). There is no significant difference of pest populations recorded between the various Bt cotton genotypes

Analysis of a multiserver queue with setup times

This paper deals with the analysis of an M/M/c queueing system with setup times. This queueing model captures the major characteristics of phenomena occurring in production when the system consists in a set of machines monitored by a single operator.We carry out an extensive analysis of the system including limiting distribution of the system state, waiting time analysis, busy period and maximum queue length