A volume-tracking method for the modelling of multi-fluid flows in engineering unit operations

A numerical code is presented for the numerical simulation of multi-fluid flows in pyrometallurgical unit operations. The code, MFVOF, is a finite difference code that allows transient solutions to immiscible multi-fluid flow problems to be generated in 2-D Cartesian and cylindrical geometries. The code is based on the use of an accurate PLIC (piecewise linear interface calculation) volume-tracking scheme to track the distortions of fluid bodies, with a redistribution procedure to ameliorate the formation of subgrid-scale fluid ligaments. Other recent enhancements to the code include swirl and expansion/compression modelling. The MFVOF code is not only able to model flows with low-curvature interface traditional applications of volume tracking - it is also able to generate robust and realistic transient representations of fragmentation and coalescence involving higher-curvature interfaces. This suggests that volume tracking can become increasingly useful for multi-phase flow modelling in chemical engineering unit operations, beyond traditional civil engineering and metallurgical applications

A mutation (N177S) in the structurally conserved helix initiation peptide motif of keratin 5 causes a mild EBS phenotype

Epidermolysis bullosa simplex (EBS) is a group of predominantly autosomal dominant hereditary disorders of the skin, which manifest as superficial skin blisters after minimal mechanical trauma. Three subtypes have been defined, based on clinical severity. Mutations affecting the genes encoding the epidermal keratins 5 (K5) and 14 (K14) have been linked to the disease, and generally those affecting the helix initiation and termination peptide motifs have been linked to severe EBS phenotypes. We report here a novel mutation in the helix initiation peptide of K5, N177S, that causes only a mild EBS-Weber Cockayne phenotype (EBS-WC). The mutation was identified by direct sequencing of polymerase chain reaction (PCR)-amplified genomic DNA encoding the exons of the KRT5 and KRT14 genes, and confirmed by mismatch allele-specific PCR, followed by restriction enzyme digestion with Tsp509 I. The patient is heterozygous for a mutation affecting codon 177, changing a conserved asparagine residue (N) to serine (S). Asparagine 177 is a highly conserved residue among all type II keratins. This is also the first report of a mutation at position 9 of 1A helix (1A:N9S) in a type II keratin. Unlike mutations affecting residues 4, 5, 7, 8, 10, and 11 of the 1A helix of K5 and K14, which were all previously linked to more severe (EBS) phenotypes, K5 1A:N9S produces only a mild EBS-WC phenotype