Background Lima bean (Phaseolus lunatus L.) is a member of subfamily Phaseolinae belonging to the family Leguminosae and an important source of plant proteins for the human diet. As we all know, lima beans have important economic value and great diversity. However, our knowledge of the chloroplast genome level of lima beans is limited. Results The chloroplast genome of lima bean was obtained by Illumina sequencing technology for the first time. The Cp genome with a length of 150,902 bp, including a pair of inverted repeats (IRA and IRB 26543 bp each), a large single-copy (LSC 80218 bp) and a small single-copy region (SSC 17598 bp). In total, 124 unique genes including 82 protein-coding genes, 34 tRNA genes, and 8 rRNA genes were identified in the P. lunatus Cp genome. A total of 61 long repeats and 290 SSRs were detected in the lima bean Cp genome. It has a typical 50 kb inversion of the Leguminosae family and an 70 kb inversion to subtribe Phaseolinae. rpl16, accD, petB, rsp16, clpP, ndhA, ndhF and ycf1 genes in coding regions was found significant variation, the intergenic regions of trnk-rbcL, rbcL-atpB, ndhJ-rps4, psbD-rpoB, atpI-atpA, atpA-accD, accD-psbJ, psbE-psbB, rsp11-rsp19, ndhF-ccsA was found in a high degree of divergence. A phylogenetic analysis showed that P. lunatus appears to be more closely related to P. vulgaris, V.unguiculata and V. radiata. Conclusions The characteristics of the lima bean Cp genome was identified for the first time, these results will provide useful insights for species identification, evolutionary studies and molecular biology research.

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Polyethylene pipes reinforced by winding steel wires (PSP) have been widely used in many fields such as chemical engineering, pulp conveying, water supply, etc. The combined loads of inner pressure and bending sometimes leads to the failure of PSP, and for engineering projects it is still not proposed that the failure criterion of PSP subject to combined loads. In this paper, full-size finite element models (FEM) of PSP under inner pressure and bending were established to investigate the engineering failure criterion. In the FEM the steel wires and HDPE matrix were modeled separately. The freedom degrees of steel wires and HDPE were coupled together as the interface between these two constituents were considered intact. The investigation contains two parts: firstly, a FEM was established in reference to the details of an existing experiment, including the pipe specimen and relative boundary condition. The validation of the FEM was carried out and the simulation result agreed well with test result indeed. Subsequently, the model was optimized to undertake four-point bending under inner pressure, to analyze the failure behavior of PSP under this kind of condition, with three factors such as varied ratio of diameters to thickness, inner pressure and volume ratio of steel wires. In the end, the curvature of failed PSP was considered as the failure criterion, and the relationship of curvature and the three factors were discussed. This paper is useful for the safety of PSP subject to inner pressure and bending load.