Effect of Coolant Temperature on Machining Characteristics of High Carbon Steel

This paper reports on the effect of coolant temperature on machining of high carbon steels. The development of a cooling system to reduce the temperature of water soluble coolant to 7.9oC from ambient temperature was employed in this work to improve the machining performance. The experiments were performed using cooled and ambient temperatures by employing Taguchi L18 orthogonal array to design the experimental runs. The cutting speed, feed rate and depth of cut were the machining parameters used; while the tool-work piece interface temperature was monitored using a digital thermometer with k-type thermocouple wire. The selected control factors are material removal rate and surface roughness. The experimental results were analyzed using Minitab 16. The main effects and percentage contributions of various parameters affecting surface roughness and material removal rate were discussed, and the optimal cutting conditions were determined. It was observed that surface finish improved by 65% with the use of the developed cooled system. The reduction in coolant temperature played a vital role in improving surface finish during machining high carbon steels

Cryptic Eimeria genotypes are common across the southern but not northern hemisphere

The phylum Apicomplexa includes parasites of medical, zoonotic and veterinary significance. Understanding the global distribution and genetic diversity of these protozoa is of fundamental importance for efficient, robust and long-lasting methods of control. Eimeria spp. cause intestinal coccidiosis in all major livestock animals and are the most important parasites of domestic chickens in terms of both economic impact and animal welfare. Despite having significant negative impacts on the efficiency of food production, many fundamental questions relating to the global distribution and genetic variation of Eimeria spp. remain largely unanswered. Here, we provide the broadest map yet of Eimeria occurrence for domestic chickens, confirming that all the known species (Eimeria acervulina, Eimeria brunetti, Eimeria maxima, Eimeria mitis, Eimeria necatrix, Eimeria praecox, Eimeria tenella) are present in all six continents where chickens are found (including 21 countries). Analysis of 248 internal transcribed spacer sequences derived from 17 countries provided evidence of possible allopatric diversity for species such as E. tenella (FST values ⩽0.34) but not E. acervulina and E. mitis, and highlighted a trend towards widespread genetic variance. We found that three genetic variants described previously only in Australia and southern Africa (operational taxonomic units x, y and z) have a wide distribution across the southern, but not the northern hemisphere. While the drivers for such a polarised distribution of these operational taxonomic unit genotypes remains unclear, the occurrence of genetically variant Eimeria may pose a risk to food security and animal welfare in Europe and North America should these parasites spread to the northern hemisphere

The Role of Soil Seed Bank in Forest Regeneration

Forest degradation and deforestation disrupts the structure and functions of the ecosystem with negative impacts on biodiversity and natural regeneration of the forests. In Nigeria, forests are lost through burning, shifting cultivation and logging of trees, thus reducing the potential of the forest to naturally regenerate and perform ecosystem functions as expected in a forest reserve. There have been insufficient knowledge about the role soil seed bank plays in forest restoration, and this will play an essential role in the natural regeneration of forest reserves. Seed bank performs tremendous roles in the restoration of degraded forest reserves, which includes donation of propagules, conservation of genetic diversity, the composition of the understorey plant community and recovery of biodiversity. These ecosystem functions are dependent on the dynamics of the soil seed bank as well as favourable environmental conditions