Precisely describing the formation and evolution rules of coal-rock fracturing crack have great value on reservoir fracturing improvement and highly efficient mining of coal bed methane well. In this paper, a non-linear dynamic method is used to study crack damage evolution behavior of coal-rock fracturing. Considering distribution characteristics of natural cracks in coal-rock, and based on da...

conclusions this study provides support for the hypothesis that humans are probably infected after contact with swine sources. the findings emphasize the importance of checking the country of origin of swine and of improving sanitary control measures from the veterinary standpoint to prevent the spread of hev infection in italy. materials and methods a total of 327 hev sequences of swine and hu...

human mitochondrial dna (mtdna) is 16,569 base pairs (bp) in length, coding for 37 genes. during the course of evolution, nearly all the genes expressing ribosomal proteins and ribosomal rnas (rrna) genes have been transferred from the mitochondria to the nucleus. however, mitochondrial dna contains two ribosomal rnas genes (12s and 16s), which have not yet transferred to the nucleus. these two...

iranian historical houses constitute a significant part of the architectural heritage of the country both qualitatively and quantitatively though due research is not conducted on them. this study investigates t0he physical evolution of qajar house of baqeri in gorganand attempts to monitor life stream over its lifespan. the study also investigates the effect of external transformations on archi...

this paper presents a model for constrained multiobjective optimization of mixed-cropping planning. the decision challenges that are normally faced by farmers include what to plant, when to plant, where to plant and how much to plant in order to yield maximum output. consequently, the central objective of this work is to concurrently maximize net profit, maximize crop production and minimize pl...