Analytical study of the annular flow of a generalised Phan-Thien–Tanner fluid

The authors would like to thank Professor Manuel A. Alves for insightful discussions on the work. Funding Open access funding provided by FCT|FCCN (b-on). Publisher Copyright: © 2023, The Author(s).The annular flow of complex viscoelastic fluids, described by the generalised Phan-Thien–Tanner model, is studied. This model considers the Mittag-Leffler function instead of the usual linear or exponential functions of the trace of the stress tensor, and includes two new parameters that provide additional fitting flexibility. We derive a semi-analytical solution that provides a better understanding of the behaviour of this type of fluid in annular flows and also helps to improve the modelling of complex materials.publishersversionpublishe

Characterization of the heat transfer coefficient in thermoplastic profile extrusion

The main objective of this work is to design a prototype system that will enable the determination of realistic values for h at the interface polymer-calibrator in real and varied extrusion conditions. The data obtained will allow improving the accuracy of the numerical codes that are being developed by the research team, through the implementation of realistic models for h.FC

Modelling the extrusion cooling/calibration stage for complex thermoplastic profiles

The main objective of this work is to implement a 3D non-isothermal multi-domain numerical code, based on finite volume method, able to deal with unstructured meshes that can be used to aid the design of calibration/cooling systems. At the final stage the code should incorporate the major phenomena that take place during profile cooling, including the prediction of the developed thermal residual stresses.Fundação para a Ciência e a Tecnologia (FCT

Valorization of brewery waste through Polyhydroxyalkanoates production supported by a metabolic specialized microbiome

Raw brewers’ spent grain (BSG), a by-product of beer production and produced at a large scale, presents a composition that has been shown to have potential as feedstock for several biological processes, such as polyhydroxyalkanoates (PHAs) production. Although the high interest in the PHA production from waste, the bioconversion of BSG into PHA using microbial mixed cultures (MMC) has not yet been explored. This study explored the feasibility to produce PHA from BSG through the enrichment of a mixed microbial culture in PHA-storing organisms. The increase in organic loading rate (OLR) was shown to have only a slight influence on the process performance, although a high selectivity in PHA-storing microorganisms accumulation was reached. The culture was enriched on various PHA-storing microorganisms, such as bacteria belonging to the Meganema, Carnobacterium, Leucobacter, and Paracocccus genera. The enrichment process led to specialization of the microbiome, but the high diversity in PHA-storing microorganisms could have contributed to the process stability and efficiency, allowing for achieving a maximum PHA content of 35.2 ± 5.5 wt.% (VSS basis) and a yield of 0.61 ± 0.09 CmmolPHA/CmmolVFA in the accumulation assays. Overall, the production of PHA from fermented BSG is a feasible process confirming the valorization potential of the feedstock through the production of added-value products.info:eu-repo/semantics/publishedVersio

Pathways of SME Internationalization: a bibliometric and systematic review

Business is dynamic and rapidly changing. Global markets were previously the playing field of multinational corporations (MNCs), while small and medium enterprises (SMEs) were local; however, the removal of imposed barriers, and recent technological advances in manufacturing, transportation and communications have indorsed SMEs and international entrepreneurs (IE) global access. SMEs and IEs are increasingly fueling economic growth and innovation and these trends are presenting both opportunities and challenges to both MNCs and SMEs in the global arena. This review systematically examines comparative SME and IE research, analyzing (after fine tuning) 762 articles published in leading journals from 1992 to September 2018. Our bibliometric and systematic review classifies SME and IE research findings into three echelons: (i) subjects; (ii) theories; and (iii) methods

Optimcool : optimization of the cooling/calibration of complex thermoplastic profiles during extrusion

Fundação para a Ciência e a Tecnologia (FCT