This research work investigated the corrosion rate of cold worked mild carbon steel in Hydrochloric acid, Nitric acid, Acetic acid, Hydrogen tetraoxosulphate (VI) acid, and phosphorus acid, to determine the corrosivity of each of the acids, and susceptibility cold worked mild steel to corrosion in the used environment, using weight loss measurement approach. The coupons were measured prior to immersion and different weight measurement taken at interval of 24 hours, over the period of 168 hours. The difference in weight between the original weight and the weight at each 24 hour interval (weight loss), was estimated and used for calculating the corrosion rates. The results obtained showed that t HNO3 is more aggressive in all the five acids considered.

The bovine rumen is main digestive site, but there exist complex variety of microorganisms, These microbial populations are generally influenced by the food supply, host genotype, health status, living environment, and the population effects of co-living microorganisms in the environment, which affects the utilization of feed and cattle health, so it is necessary to make clear bovine rumen microbial population. In this paper, a strain of bovine rumen lactic acid bacteria (Y-B-1) was isolated from adult bovine rumen by anaerobic isolation technique. By analyzing the morphology of bacteria, combining with sugar fermentation test, using biochemical identification tube to carry out physiological and biochemical tests of the strain. Finally, the homology analysis of 16S rRNA sequence was carried out. The results showed that the strain of Y-B-1 was Pediococcus pentosaceus. The biological characteristics of the strain were studied, and the optimum growth temperature was determined. The results showed that the strain grew best at 30°C, pH 5.5 pH 7.5, and salt ion concentration below 7.5.