Ultra‐flexible PLA

Mono-material in the manufacturing of oil-based plastic bottles has been so far not considered because of the poor flexibility of polyethylene terephthalate (PET). The undercuts of PET caps (i.e., the threads of the screw caps) would be torn-off during the ejection step of the injection/compression molding processes that are commonly used to fabricate them. In this respect, the present work deals with the design and development of innovative biodegradable polyester-based blends with high flexibility, intended for the manufacturing of screw-cap, being this element the most critical in the implementation of the complete bottle. The blend is based on polylactic acid and it is tailored for injection molding of tamper-evident screw plastic caps by the addition of another biodegradable polyester, that is, polybutylene adipate-co-terephthalate. The effect of the addition of a barrier agent, polyvinyl alcohol, on the overall behavior of the blends was also studied in the perspective of the implementation of caps featuring barrier properties against water vapor and oxygen. The same material could be, however, easily tailored for the fabrication of the bottle body and printed label to get to the mono-material bottle. Twin-screw corotating extrusion of the compound, injection molding of the plastic material for the fabrication of the screw caps, and evaluation of the thermophysical and mechanical properties of the screw caps are hereinafter discussed. The biodegradable polyester-based blends are found to be suitable for injection molding of the tamper-evident screw caps, exhibiting adequate flexibility during ejection from the mold. The screw caps can also boast appreciable mechanical strength and impact resistance as well as good thermal stability

Introduction and summary

Due to copyright restrictions, the access to the full text of this article is only available via subscription.Control and optimization of dynamical systems in the presence of stochastic uncertainty is a mature field with a large range of applications. A comprehensive treatment of such problems can be found in excellent books and other resources including [7, 16, 29, 68, 84, 95, 104], and [6]. To date, there exist a nearly complete theory regarding the existence and structure of optimal solutions under various formulations as well as computational methods to obtain such optimal solutions for problems with finite state and control spaces. However, there still exist substantial computational challenges involving problems with large state and action spaces, such as standard Borel spaces. For such state and action spaces, obtaining optimal policies is in general computationally infeasible

Genes and Quantitative Trait Loci Mapping for Major Agronomic Traits in Brassica napus L

International audienceThe advent of high-throughput genomic technologies and the availability of a reference genome sequence of Brassica napus and its diploid parental species, B. rapa and B. oleracea, open new insights into the genomic localization of agronomic trait-associated quantitative trait loci (QTL), the identification of underlying genes and their sequence variation. Over the last 20 years, many genetic maps of B. napus have been built, progressively integrating various types of markers. Large single-nucleotide polymorphism (SNP) arrays allowed the construction and integration of high density maps and their anchorage to the B. napus sequence. Increasingly, precise genetic analyses of agronomic traits could thus be carried out, either through linkage analysis or through genome-wide association mapping. Comparative genomics allowed the genomic localization of the genes and QTL controlling agronomic traits, as well as an assessment of the impact that the high level of duplications present in this polyploid species has on the genetic architecture of the traits and on the structural and functional diversity of the genes involved. This chapter reviews the evolution of B. napus genetic and genomic resources and their use in gene and QTL mapping for several major traits and then shows how the availability of the B. napus genome sequence allows more accurate investigation of the genomic regions and underlying genes involved