198,061 research outputs found
Yves Coppens, un griot de nos origines
No full textYves Coppens, en 2007, dans les collections du Ditsong Museum of Natural History à Pretoria présentant le célèbre crâne de Mrs Ples (Australopithecus africanus), provenant du gisement sud-africain de Sterkfontein © B. Senut Yves Coppens, grand scientifique et humaniste, né à Vannes le 09 aout 1934, s’est éteint le 22 juin dernier à Paris. Passionné de paléontologie, de préhistoire et d’archéologie, il était un curieux du passé et s’intéressait à des périodes variées de notre histoire : des m..
Grassmannians of secant varieties
No full textFor an irreducible projective variety X, we study the family of h-planes contained in the secant variety Sec_k(X), for
Limit Weierstrass schemes on stable curves with 2 irreducible components
No full textThe paper is concerned with limits of Weierstrass points under degeneration of smooth curves
to stable curves of non compact type, union of two irreducible smooth components meeting transversely at
m ≥ 1 points. The cas
Nature-inspired chemical engineering, a transformative methodology for innovation
No full textSome of our greatest challenges involve clean energy, water, the environment, dwindling resources, sustainable manufacturing, and healthy ageing. To approach them, chemical engineers are well equipped with the basic tools: balances, systems modeling, thermodynamics, kinetics and transport phenomena. Nevertheless, how these tools are employed in process and product design requires rethinking. Tackling Grand Challenges requires step-changes through transformative approaches and lateral thinking across disciplines, beyond incremental variations on traditional designs.
Nature is filled with well-integrated, “intensified” systems, optimized over the eons, to satisfy stringent constraints for survival by scalable processes with emergent properties. We propose to take nature as a source of inspiration, leveraging fundamental mechanisms underpinning desirable properties (like scalability, resilience or efficiency) and applying these to engineering designs, with suitable adaptations to satisfy the different contexts of technology and nature. We call this approach Nature-Inspired Solutions for Engineering (NISE), and its application to chemical engineering problems Nature-Inspired Chemical Engineering (NICE) [1].
The need to think about the context of technological applications, and the consistent use of fundamental scientific insights rather than superficial similarities, sets nature-inspired engineering apart from biomimetics or biomimicry. Examples from architecture and structural engineering will be given to illustrate this difference [2].
This lecture will introduce NICE as a systematic methodology [1] that is thematically structured around ubiquitous, fundamental mechanisms in nature, in particular: (T1) hierarchical transport networks, (T2) force balancing, (T3) dynamic self-organization, and (T4) control mechanisms in ecosystems, biological networks and modularity.
Thus, NICE looks at nature with the eyes of an engineer, employing scientific tools to derive nature-inspired concepts that are, subsequently, systematically used in the nature-inspired design of solutions to real problems, aided by mathematical and computational modeling and experimentation. In our examples, we will see how we learn from trees, lungs, kidneys, and dunes to intensify chemical and energy processes, and how we discover materials for biomedicine and the built environment, using the NICE methodology [1-6].
The NICE approach is powerful, because it allows us to merge creativity with rational design. Being thematic and systematic, once validated for one problem, NICE can be employed to solve various similar problems in other fields, e.g., from fluidized beds to fuel cells, and from catalysts to dental materials. Ultimately, the NICE methodology is a practical pathway for innovation and design.
References
[1] M.-O. Coppens, 2012, A nature-inspired approach to reactor and catalysis engineering. Curr. Op. Chem. Eng. 1, 281-289.
[2] A.S. Perera and M.-O. Coppens, 2018, Re-designing materials for biomedical applications:
From biomimicry to nature-inspired chemical engineering. Phil. Trans. Roy. Soc. A. 377(2138): 20180268.
[3] M.-O. Coppens and G. Ye, 2018, Nature inspired optimization of transport in porous media. In Diffusive Spreading in Nature, Technology and Society (ed.: A. Bunde, J. Caro, J. Kärger and G. Vogl), Springer.
[4] P. Trogadas, M. Nigra and M.-O. Coppens, 2016, Nature-inspired optimization of hierarchical porous media for catalytic and separation processes. New J. Chem. 40, 4016-4026.
[5] K. Wu, L. de Martín and M.-O. Coppens, 2017, Pattern formation in pulsed gas-solid fluidized beds - the role of granular solid mechanics. Chem. Eng. J. 329, 4-14.
[6] P. Trogadas, J.I.S. Cho, T.P. Neville, J. Marquis, B. Wu, D.J.L. Brett and M.-O. Coppens, 2018, A lung-inspired approach to scalable and robust fuel cell design. Energy & Env. Sci. 11, 136
Le P. Urbain Coppens, O. F. M. Le Palais de Caïphe et le nouveau jardin Saint-Pierre des Pères Assomtionistes au mont Sion Paris, Picard, 1904
No full textL. A. Le P. Urbain Coppens, O. F. M. Le Palais de Caïphe et le nouveau jardin Saint-Pierre des Pères Assomtionistes au mont Sion Paris, Picard, 1904. In: Bibliothèque de l'école des chartes. 1906, tome 67. pp. 124-125
Indirect effects - a formal definition and degrees of dependency as an alternative to technical coefficients
No full textThe use of input-output analysis for the computation of secondary effects of final demand changes is well-known. These 'final demand effects' can be calculated using technical coefficients and the inverse of the Leontief matrix. This paper offers an alternative to the use of technical coefficients. Its goal is threefold. First of all degrees of dependency are defined and it is shown how they can be used to compute secondary effects. Their definition is based on an input-output table. Secondly the concept of secondary effects is extended to what is called indirect effects. These indirect effects are not only related to final demand but to total industry output. It is shown how these indirect effects can be calculated using technical coefficients or degrees of dependency. The method used is a variant of the so-called Hypothetical Extraction Methods. Double counting is avoided, as such the resulting multipliers are 'net multipliers'. It is formally demonstrated that technical coefficients and degrees of dependency give the same results when a recent input-output table is available. If this is not the case then the results are different. It is impossible to say which of the two estimates is better. Since technical coefficients are already broadly accepted, some examples are given to justify the use of degrees of dependency. Finally it is explained how the unavailability of an input-output table can be solved. Starting from the supply-use tables a 'quick and dirty method' to infer an input-output table is provided. This topic is justified by the fact that for Belgium input-output tables are only published for those years that are divisible by five, with a three year lag. A short empirical analysis, based on currently available data, shows that technical coefficients and degrees of dependency have comparable performance, with a slight advantage for the technical coefficients. This performance is measured relative to a 'right' result, being the indirect effects for the year 2000 computed using the now available input-output table for the year 2000. This result is called 'right' because it does not make any assumptions on stability of technical coefficients nor of degrees of dependency. The empirical analysis also compares the use of a recent supply-use table to the use of an old input-output table. Supply-use tables on average overestimate the 'right' result. They are however often closest to the 'right' result at the first level. Since these conclusions are based on limited data further analysis is required as more data becomes available.indirect effects, input-output analysis, degrees of dependency, technical coefficients, net multiplier
Plangebied jachthaven Lagedijk te Penningsveer, gemeente Haarlemmerliede en Spaarnwoude; archeologisch vooronderzoek: een inventariserend veldonderzoek
No full textCoordinaten: 106.551/489.773
Datum einde onderzoek: april 2008, rapportage: 04-07-2008
Projectmedewerkers: M. Rietkerk, C. Coppens, F. Stevens, I. Briels
Complextype(n):xxx, NHP
Datering: 17e-18e eeuw
Diversen:Coppens, C.F.H. Plangebied jachthaven Lagedijk te Penningsveer, gemeente Haarlemmerliede en
Spaarnwoude; archeologisch vooronderzoek: een inventariserend veldonderzoek, RAAPrapport 1729 (WEESP, 2008)
In verband met voorgenomen infrastructurele bouwwerkzaamheden die archeologische waarden zouden kunnen verstoren, voert RAAP een vooronderzoek uit. Dit booronderzoek is een vervolg op een bureauonderzoek met code 2641
New archaeological investigation in the sun temple of Niuserra in Abu Ghurab
No full textThe article presents the results of the first field-works in the temple of Niuserra at Abu Ghurab more than one hundred years from the discovery and publication of the temple by Borchardt. The sun temple built by Niuserra is the only one, out of the six temples known from the epigraphic sources, greatly preserved and whose structures are still recognizable. This new investigation is not based on new excavations of the temple but rather on a re-evaluation of the archaeological data still available on the site as well as an attempt to clarify the architectural and functional features of some of the structures and to suggest a new, revisited plan of the temple itself by means of the modern topographical and technological instruments.
In this sense, attention has been particularly focused on the general measurements of the temple made by Borchardt and on some specific areas like, above all, the obelisk and the so-called “magazines” whose architectural layout and symbolical value seem to have been sometimes misinterpreted by the German scholar. After two archaeological campaigns it was possible to ascertain that, although Borchardt’s work in the temple still remains a key-point in the understanding and comprehension of the architectural features of such kind of religious buildings, many interesting archaeological data still need further, accurate investigation
The single European electricity market: A long road to convergence. NBB Working Paper Nr. 84, May 2006
No full textIn the context of a first Working Paper the authors argued that electricity has a number of characteristics that set it apart from other commodities. It was demonstrated that some of these characteristics might complicate the deregulation process. This paper analyses the ongoing deregulation process in the European electricity sector and attempts to establish whether these difficulties can more readily be solved at European level. It would appear that some problems, e.g. economies of scale in electricity generation, have less of an impact at European level than within smaller national markets. However, a number of difficulties have to be overcome before a unified European electricity market can become a reality. These include the limited interconnection capacities between Member States. The European Commission has taken steps to improve the situation, for example by offering financial support for investments and promoting the development of regional markets as an interim measure ultimately leading to a fully integrated market. Apart from the difficulties related to electricity generation and transmission there are also exogenous factors that influence the ongoing deregulation process, e.g. the implementation of the Kyoto protocol and the dramatic increases in primary fuel prices. This paper argues that a consistent, stable and uniform European regulatory framework must be put in place if the impact of these difficulties is to be minimised
Rapport fait à l'Assemblée nationale, le 3 novembre 1791, par M. Coppens ([Reprod.])
No full textCollection : Les archives de la Révolution française ; 11.1b.247Collection : Les archives de la Révolution française ; 11.1b.24
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