685 research outputs found
Healcon: self-healing concrete to create durable and sustainable concrete structures
No full textWithin the theme ‘Self-healing materials for prolonged lifetime’ (NMP.2012.2.1-3) of the Seventh Framework Programme, self-healing concrete is an important topic. The project HEALCON, which deals with self-healing concrete to create durable and sustainable concrete structures, is funded by EU-FP7 and started in January 2013. The coordinator of the project is Prof. Nele De Belie (UGent) and the consortium partners are UGent, Avecom, TU Delft, Acciona, TUM, TTI, VTT, COWI, DTI, CEINNMAT, Devan and Fescon.
Adequate perpetuation of the road, tunnel and bridge network, is crucial to preserving European cohesion and business operations; and around 70% of this infrastructure is made of concrete. In order to garantuee liquid tightness of concrete structures, and enhance durability of elements prone to bending cracks, smart concrete with selfhealing properties will be designed.
Thanks to the existing expertise of the consortium in the field of self-healing concrete at a lab-scale, a thoughtful selection of promising techniques is possible.
- For early age cracks, a non-elastic repair material can be proposed, such as calcium carbonate precipitated by bacteria, or new cement hydrates of which the formation is stimulated by the presence of hydrogels.
- For moving cracks under dynamic load, an elastic polymeric healing agent is suggested.
Different healing agents and encapsulation techniques are tested and scaled up. Self-healing efficiency is evaluated in lab-scale tests using purposefully adapted monitoring techniques, and optimized with the help of suitable computer models.
Finally the efficiency is validated in a large scale lab test and implemented in an actual concrete structure. Life-cycle cost analysis will show the impact of the selfhealing technologies on economy, society and environment compared to traditional construction methods
Een monument voor het land : overheidsstatistiek in België, 1795-1870
No full textIn A monument to the country. Official statistics in Belgium, 1795-1870, Nele Bracke unravels why and how the Belgian state and its predecessors organized and developed an official statistical apparatus in order to collect numerical information. The study captures the underlying objectives and structures, as well as the methods to compile statistics. Nele Bracke investigates the meaning and significance of government statistics in the 19th-century State and society. In Belgium, early social scientists established an internationally renowned ‘statistical system’ designed to collect information about the country, the people and the society. This ‘statistical system’ was built around the ‘Commission centrale de Statistique’ (statistical committee) and the production of demographic, economic and agricultural censuses. In the first part of the book, the author analyzes the institutional history of the ‘Commission centrale de Statistique’ and its predecessors. In the second part of the book, she studies the censuses
Een monument voor het land. Overheidsstatistiek in België, 1795-1870
No full textIn A monument to the country. Official statistics in Belgium, 1795-1870, Nele Bracke unravels why and how the Belgian state and its predecessors organized and developed an official statistical apparatus in order to collect numerical information. The study captures the underlying objectives and structures, as well as the methods to compile statistics. Nele Bracke investigates the meaning and significance of government statistics in the 19th-century State and society. In Belgium, early social scientists established an internationally renowned ‘statistical system’ designed to collect information about the country, the people and the society. This ‘statistical system’ was built around the ‘Commission centrale de Statistique’ (statistical committee) and the production of demographic, economic and agricultural censuses. In the first part of the book, the author analyzes the institutional history of the ‘Commission centrale de Statistique’ and its predecessors. In the second part of the book, she studies the censuses
Een monument voor het land. Overheidsstatistiek in België, 1795-1870
No full textIn A monument to the country. Official statistics in Belgium, 1795-1870, Nele Bracke unravels why and how the Belgian state and its predecessors organized and developed an official statistical apparatus in order to collect numerical information. The study captures the underlying objectives and structures, as well as the methods to compile statistics. Nele Bracke investigates the meaning and significance of government statistics in the 19th-century State and society. In Belgium, early social scientists established an internationally renowned ‘statistical system’ designed to collect information about the country, the people and the society. This ‘statistical system’ was built around the ‘Commission centrale de Statistique’ (statistical committee) and the production of demographic, economic and agricultural censuses. In the first part of the book, the author analyzes the institutional history of the ‘Commission centrale de Statistique’ and its predecessors. In the second part of the book, she studies the censuses
Variability and repeatability of olfactometric results of n-butanol, pig odour and a synthetic gas mixture
No full textFor the purposes of a research project for the Flemish authorities, olfactometric measurements were carried out at six closed pig farms and six fattener farms. The results of these olfactometric measurements were compared with the olfactometric results of n-butanol samples and samples of a synthetic gas mixture of ethanethiol, methylacetate and 2-propanol in nitrogen, both analysed on the same days as the air samples from the pig farms. The results of the n-butanol tests for all panellists showed that nobody was qualified according to the CEN criteria, and that, consequently, these criteria are rather stringent. Comparing the variability of the results for the three different odours showed that the mean and standard deviation of the mean variance were not significantly different for the three odour types, which means that the repeatability of the panellist results was equal for the examined odour types. The principle of traceability was checked by comparing the variance of the n-butanol, pig odour and synthetic mixture ratio. For the complete dataset, the principle of traceability could not been proven for n-butanol. For the restricted dataset, the principle of traceability was more valid for n-butanol than for the mixture, but differences were small. Finally, normalization was looked for with regard to olfactometric measurements of air samples from pig farms based either on n-butanol or on the synthetic mixture. Both models had low determination coefficients, but the model based on the synthetic mixture gave better results than the one based on n-butanol.</jats:p
Evidence for a role of nitric oxide in iron homeostasis in plants
No full textNitric oxide (NO), once regarded as a poisonous air pollutant, is now understood as a regulatory molecule essential for several biological functions in plants. In this review, we summarize NO generation in different plant organs and cellular compartments, and also discuss the role of NO in iron (Fe) homeostasis, particularly in Fe-deficient plants. Fe is one of the most limiting essential nutrient elements for plants. Plants often exhibit Fe deficiency symptoms despite sufficient tissue Fe concentrations. NO appears to not only up-regulate Fe uptake mechanisms but also makes Fe more bioavailable for metabolic functions. NO forms complexes with Fe, which can then be delivered into target cells/tissues. NO generated in plants can alleviate oxidative stress by regulating antioxidant defense processes, probably by improving functional Fe status and by inducing post-translational modifications in the enzymes/proteins involved in antioxidant defense responses. It is hypothesized that NO acts in cooperation with transcription factors such as bHLHs, FIT, and IRO to regulate the expression of enzymes and proteins essential for Fe homeostasis. However, further investigations are needed to disentangle the interaction of NO with intracellular target molecules that leads to enhanced internal Fe availability in plants.RKT is grateful to Department of Science and Technology-Science and Engineering Research Board (DST-SERB) New Delhi, for a Teachers Associateship for Research Excellence (TAR/2019/000064).Tewari, RK (corresponding author), Univ Lucknow, Dept Bot, Lucknow 226007, Uttar Pradesh, India.
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Expect the Unexpected: Organizational Purpose as Enabler of Serendipitous Impact
No full textChristian Busch, author of The Serendipity Mindset: The Art and Science of Creating Good Luck, and Nele Terveen explain how purpose helps leaders connect the dots between grand challenges and strategic responses. When leaders expect the unexpected, the authors explain, they incent their stakeholders to embrace uncertainty so they can better guide their organizations through adversity and disruption. By leveraging the five practices of Serendipitous Impact (impact mission, impact leadership, impact governance, impact networks, and impact measurement) unexpected events can help leaders come up with solutions that often cannot be seen, let alone fully defined, in advance.https://www.cutter.com/journal/scaffolding-purpose-times-polycrisi
Non-destructive testing techniques for the observation of healing effects in cementitious materials: an introduction
No full textTo develop an appropriate method of self-healing for cementitious materials including the right composition and amount of suitable healing agents it is required to investigate the healing efficiency for certain material mixtures. While some researchers evaluate the regain in compressive strength by means of destructive load tests, this method is obviously second best in particular for field applications. In a large EU project the best candidates among the non-destructive testing methods are investigated to be applied in small and large laboratory experiments as well as at real structures in-situ. The paper is giving an introduction to these techniques and addresses also issues of structural health monitoring used for example to monitor the healing effects on a long term basis and to assess the condition of the structure, where self-healing techniques are applied
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