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The present study is focused on studying the effect of alkali treatment on the mechanical properties of banana fiber-reinforced epoxy composites. Four batches of samples were prepared with respect to the percentage of sodium hydroxide (NaOH) in the treatment solution (0%, 2.5%, 4.5%, and 6.5%). Later mechanical tests such as tensile, compressive, and interlaminar shear tests were conducted on the prepared composite specimens to determine the influence of alkali treatment on the mechanical characteristics. The test results indicate an overall improvement in all the mechanical properties due to the fiber treatment. Moreover, the samples made from the fiber treated with 4.5% of NaOH solution indicated the highest tensile strength and compressive strength, with an overall increment of 24.2% and 34.8% in tensile and compressive strengths, respectively, when compared with the untreated sample. A linear increment in interlaminar strength is observed with a maximum value of 25.4 N/mm2 for the sample made from the fiber treated with 6.5% of NaOH solution. This increase is due to the fiber flattening process which increases the bonding surface at the interface.

Carbide phase transformation and alloying element partitioning in service exposed (about 45 000 -160 000 h) 2 . 25Cr -1Mo boiler tubes from a thermal power station were studied using X-ray diffraction and X-ray uorescence techniques on electrochemically extracted carbide precipitates. The objective of the present investigation was to develop a faster method of health assessment of this steel at elevated temperatures on a routine basis. Various carbide phases were detected with different lengths of service. The molybdenum content in extracted carbide specimens showed a systematic decrease with aging. Replenishment of molybdenum in the matrix may be a useful indicator in life assessment of this steel. When the dissolved molybdenum content in the matrix was less thañ 0 . 8 wt-%, the hardness of service exposed specimens was found to decrease. However, carbide precipitates extracted from new specimens subjected to accelerated heat treatment at 600 and 700°C showed an increase in molybdenum content with increase in temperature. The X-ray data were supplemented by microscopy, EDAX and hardness measurements.MST/5687