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Skachat Garshin Signal Fb2 VERIFIED

Silicon nitride (Si3N4) ceramic is highly desired in various engineering applications due to its exceptional properties. However, machining the Si3N4 ceramic suffers setbacks due to various degrees of damage inflicted on the ceramic during machining. Studies have shown that the minimum quantity lubrication (MQL) process is a better alternative to the flood cooling lubrication system during grinding of advanced engineering ceramics. The MQL technique is a highly efficient and eco-friendly lubrication method that can be used to reduce the different types of surface and subsurface damages, while significantly lowering the consumed lubricant. In this work, the performance of the MQL and flood cooling lubrication techniques during grinding of Si3N4 ceramic was investigated. The MQL nanolubricant was formed by suspending silicon dioxide (SiO2) nanoparticles in environmentally friendly vegetable oil (canola oil). Also, the effect of the input parameters, i.e., feed rate, depth of cut, type of diamond wheel, and lubrication type, were investigated on the output parameters, i.e., grinding forces, workpiece surface roughness, surface damages, and wheel wear. The Taguchi mixed-level parameter experimental design (L16) was used in the design of the experiment, and the signal-to-noise ratio was used to optimize the grinding process. Furthermore, the adaptive neuro-fuzzy inference system (ANFIS) prediction method was used to predict and analyze the variation of the input parameters with the grinding forces and surface roughness. Validation experiments also indicate that the ANFIS models for the normal grinding force, tangential grinding force, and surface roughness have accuracies of 98.45, 98.58, and 96.31%, respectively.

skachat garshin signal fb2

Sexual selection is a well-known biological process, yet the genomic basis and patterns of sexual selection are not fully understood. The extravagant ornamental plumage of peacock (Pavo cristatus) was instrumental in shaping Charles Darwin's theory of sexual selection and is considered to be an honest signal of its immunocompetence. Here, we used the recently generated draft genome sequence of peafowl (Pavo cristatus) and carried out a comparative analysis across 11 bird genomes that encompass a range of sexual selection and also had high-quality genomic and phenotypic data publically available to study the genomic basis of sexual selection. We found that varying degree of purifying selection was the predominant mechanism of action for sexual selection at the genome-wide scale and observed that sexual selection mostly influences genes regulating gene expression and protein processing. Specifically, the genome-wide phylogenetically corrected regression analysis supported the continuous or ongoing model of sexual selection. Genes involved in nucleic acid binding and gene expression regulation, including a specific regulator of sex-determination known as TRA2A to be under positive selection in the species with high post-copulatory sexual selection manifested as high sperm competition. We also detected specific feather-related and immune-related gene-pairs evolving under similar selection pressures across the 11 species, including peacock (Pavo cristatus), which is consistent with the Hamilton-Zuk hypothesis. The comparative genomics analysis of 11 avian taxa has provided new insights on the molecular underpinnings of sexual selection and identifies specific genomic regions for future in-depth analysis. 041b061a72


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