Purpose: The present study deals with the numerical modeling of the low-velocity impact damage of laminated composites which have increasingly important applications in aerospace primary structures. Such damage, generated by various sources during ground handling, substantially reduces the mechanical residual performance and the safe-service life. The purpose of this paper is to present and validate a computationally efficient approach in order to explore the effect of critical parameters on the impact damage characteristics.Design/methodology/approach: Numerical modeling is considered as one of the most efficient tool as compared to the expensive and time-consuming experimental testing. In this paper, a finite element model based on explicit dynamics formulations is adopted. Hashin criterion is applied to predict the intralaminar damage initiation and evolution. The numerical analysis is performed using the ABAQUS® programme. Findings: The employed modeling approach is validated using corresponding numerical data found in the literature and the presented results show a reasonable correlation to the available literature data. It is demonstrated that the current model can be used to capture the force-time response as well as damage parameter maps showing the intralaminar damage evolution for different impact cases with respect to the physical boundary conditions and a range of impact energies. Originality/value: Low-velocity impact damage of laminated composites is still not well understood due to the complexity and non-linearity of the damage zone. The presented model is used to predict the force-time response which is considered as one of the most important parameters influencing the structural integrity. Furthermore, it is used for capturing the damage shape evolution, exhibiting a high degree of capability as a damage assessment computational tool.
As the two prime examples of sport light, running and walking have become very popular sports activities in the past decades. There are references in the literature of similarities between both sports, however these parallels have never been studied. In addition, the current digitalisation of society can have important influences on the further diversification of profiles. Data of a large-scale population survey among runners and walkers (n = 4913) in Flanders (Belgium) were used to study their sociodemographic, sports related and attitudinal characteristics, and wearable usage. The results showed that walkers are more often female, older, lower educated, and less often use wearables. To predict wearable usage, sports-related and attitudinal characteristics are important among runners but not among walkers. Motivational variables to use wearables are important to predict wearable usage among both runners and walkers. Additionally, whether or not the runner or walker registers the heart rate is the most important predictor. The present study highlights similarities and differences between runners and walkers. By adding attitudinal characteristics and including walkers this article provides new insights to the literature, which can be used by policymakers and professionals in the field of sport, exercise and health, and technology developers to shape their services accordingly.
Stormwaters, flowing into storm sewers, are known to significantly increase the annual pollutant loads entering urban receiving waters and this results in significant degradation of the receiving water quality. Knowledge of the characteristics of stormwater pollution enables urban planners to incorporate the most appropriate stormwater management strategies to mitigate the effects of stormwater pollution on downstream receiving waters. This requires detailed information on stormwater quality, such as pollutant types, sediment particle size distributions, and how soluble pollutants and heavy metals attach themselves to sediment particles. This study monitored stormwater pollution levels at over 150 locations throughout the Netherlands. The monitoring has been ongoing for nearly 15 years and a total of 7,652 individual events have been monitored to date. This makes the database the largest stormwater quality database in Europe. The study compared the results to those presented in contemporary international stormwater quality research literature. The study found that the pollution levels at many of the Dutch test sites did not meet the requirements of the European Water Framework Directive (WFD) and Dutch Water Quality Standards. Results of the study are presented and recommendations are made on how to improve water quality with the implementation of Sustainable Urban Drainage Systems (SUDS) devices.
This proposal is directed at the creation of sustainable embedding and preservation methods for biomaterials, in particular those incorporating structural colours (SCs). SCs use the interaction of light with highly ordered, nanostructured materials to generate colour. SCs are intense, angle dependent, can be polarized, non-fading and non-toxic; all characteristics with advantages over pigments. SCs can be created from bacteria, are widely found in nature and offers a route to the creation of high-performance biobased materials: i.e. ‘green’ replacements for dyes. However, naturally derived structural coloured biomaterials, particularly bacteria, require preservation or embedding – an essential step in developing durable products. The current embedding agent is an epoxy resin which is not a sustainable reagent. Indeed, there is a wider need for thermoset matrix materials and other polymers that are more environmentally friendly yet with good performance and cost. In this proposal we will develop such matrix materials using bacterial SCs as a test case and the primary application.
Water treatment companies are more and more interested in chemical-free water treatment. This is a solution that might not only decrease costs of chemicals, but also decrease possible formation of by-products and contribute to decreasing the introduction of emerging contaminants in the environment. A possible route for this is the use of magnetic fields based treatment. Magnetic fields exist around us (our planet is surrounded by such fields) but are not broadly used in water treatment. A reason for this situation isthe fact that water treatment is a rather traditional market and magnetic treatment, conversely, a rather controversial and (still) not completely understood. Even with such resistance, recently it has been shown that magnetic fields applied to drinking water resulted in significant structural change of its microbiome [1]. This community structural change was clearly detected with a newly developed flow cytometry method, where the phenotypic characteristics of the entire microbial community could be analysed instantly [2-9]. Lab-scale batch experiments have shown that magnetic fields can selectively boost the growth of smaller bacteria [1][3] and indicated as a next step that the same principle could be addressed in pilot scale tests. ISusMag is structured to apply the robust and instant flow cytometry method to examine the effect of magnetic fields on drinking water at pilot scale under realistic field conditions. For this purpose, groundwater will be evenly distributed into two (pipe)lines of the same length: one will be magnetically treated, and one will be used as control. Samples will be taken at the end of the two pipes for flow cytometry examination. Measurement results can help drinking water companies to understand whether a magnetic treatment is an alternative to control the growth of pathogenic bacteria instead of classical chemical treatment (disinfection).
