Generalized behavior of the breakup of viscous drops in confinements

The breakup of confined drops in shear flow between parallel plates is investigated as a function of viscosity ratio and confinement ratio. Using a boundary-integral method for numerical simulations and a counter-rotating experimental device, critical capillary numbers in shear flow are obtained. It is observed that different viscosity ratios yield different trends with increasing confinement ratio: a low viscosity ratio drop shows an increase in critical capillary number, at a viscosity ratio of unity no major trend is seen, and the critical capillary number for a high viscosity ratio drop decreases significantly. A generalized explanation for all viscosity ratios is that confinement affects the orientation of the drop with respect to the direction of the local strain field. At moderate confinement ratios, the drop orients more towards the strain direction, where it experiences a stronger flow and hence, the critical capillary number is decreased. As the drop gets more confined, it aligns more in the flow direction. Hence, the drop experiences a weaker flow and thus, additionally stabilized by wall effects, it breaks at a higher critical capillary number. In principle, this behavior is the same for all viscosity ratios, but transitions occur at different confinement ratios. Most of the breakup is of a binary nature, but ternary breakup can occur if the drop length is larger than 6 undeformed drop radii, consistent with arguments based on the Rayleigh-Plateau instability

PROCESS AND MATERIAL OPTIMISATIONS FOR INTEGRATION OF CHOPPED GLASS FIBRES IN LASER SINTERED POLYMER PARTS

Additively manufactured polymer composites gain popularity in a variety of industries such as aerospace, biomedical and automotive. Laser sintering (LS) is a well-known AM process that typically uses polyamide which can serve as matrix material. Hence LS has the potential to produce reinforced polymers that can meet demanding requirements. In previous research, issues with powder flowability and poor fibre dispersion led to limited increase of mechanical properties. To overcome this, a novel fibre deposition system was recently developed and optimised at KU Leuven to successfully produce fibre reinforced LS samples with random inter- and intralayer fibre orientations. A limited but promising influence of deposited glass fibres on produced LS parts was noted after mechanical testing. In this work, the influence of different (heat) treatments on glass fibres used during LS will be discussed as well as the resulting differences in the fibre/matrix behaviour as analysed through hot stage microscopy.Mechanical Engineerin

Biomarkers of the transsulfuration pathway and risk of renal cell carcinoma in the European Prospective Investigation into Cancer and Nutrition (EPIC) study

Previous studies have suggested that components of one-carbon metabolism, particularly circulating vitamin B6, have an etiological role in renal cell carcinoma (RCC). Vitamin B6 is a cofactor in the transsulfuration pathway. We sought to holistically investigate the role of the transsulfuration pathway in RCC risk. We conducted a nested case-control study (455 RCC cases and 455 matched controls) within the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Plasma samples from the baseline visit were analyzed for metabolites of the transsulfuration pathway, including pyridoxal 5'-phosphate (PLP, the biologically active form of vitamin B6), homocysteine, serine, cystathionine, and cysteine, in addition to folate. Bayesian conditional logistic regression was used to estimate associations of metabolites with RCC risk as well as interactions with established RCC risk factors. Circulating PLP and cysteine were inversely associated with RCC risk, and these association were not attenuated after adjustment for other transsulfuration metabolites (odds ratio (OR) and 90% credible interval (CrI) per 1 SD increase in log concentration: 0.76 [0.66, 0.87]; 0.81 [0.66, 0.96], respectively). A comparison of joint metabolite profiles suggested substantially greater RCC risk for the profile representative of low overall transsulfuration function compared with high function (OR 2.70 [90% CrI 1.26, 5.70]). We found some statistical evidence of interactions of cysteine with body mass index, and PLP and homocysteine with smoking status, on their associations with RCC risk. In conclusion, we found evidence suggesting that the transsulfuration pathway may play a role in metabolic dysregulation leading to RCC development. This article is protected by copyright. All rights reserved

Reconceptualizing CSR in the media industry as relational accountability

In this paper, we reconceptualize CSR in the media industries by combining empirical data with theoretical perspectives emerging from the communication studies and business ethics literature. We develop a new conception of what corporate responsibility in media organizations may mean in real terms by bringing Bardoel and d’Haenens’ (European Journal of Communication 19 165–194 2004) discussion of the different dimensions of media accountability into conversation with the empirical results from three international focus group studies, conducted in France, the USA and South Africa. To enable a critical perspective on our findings, we perform a philosophical analysis of its implications for professional, public, market, and political accountability in the media, drawing on the insights of Paul Virilio. We come to the conclusion that though some serious challenges to media accountability exist, the battle for responsible media industries is not lost. In fact, the speed characterizing the contemporary media environment may hold some promise for fostering the kind of relational accountability that could underpin a new understanding of CSR in the media

Nonprofit governance and accountability : broadening the theoretical perspective

Drawing on comparative case studies, this article critiques the positioning of accountability as a benign and straightforward governance function. From a critical management studies perspective, I offer a conceptualization of the relationship between governance and accountability in which issues of power, beliefs about the nature of organizing, and social relations are integral features. The article clarifies how principal-agent governance assumptions, based on a central logic of unitarism, can drive narrow compliance-based interpretations of accountability. Such an approach appears at odds with the values embedded in the social missions of many nonprofits insofar as they prioritize small sections of powerful stakeholders over sustained periods of time. Conversely, a pluralist logic appears to create space for broad accountability to multiple stakeholders. Here, expressive, values-based accountability is seen as a source of legitimacy and can produce complex relationships, which challenge the instrumental orientation to social relations that principal-agent theories assume