Search results for " Geometry"
showing 10 items of 2294 documents
Reasons of irregularity of seed's distribution in the divider heads of air-seeders
2017
ISBN : 978-3-18-092300-0; International audience; Modern seeding equipment must allow to cultivate sizeable areas efficiently and finalize the seeding in a short amount of time. Air-seeder is a solution for a fast seeding: seeds are conveyed from the high-capacity seed hopper to the coulter-bar by an air-stream. Taking into account the complexity of this type of seed drills, they stay little-studied. Few developments have been done on divider headers responsible of distribution accuracy. This paper deals with a study on the influence of divider head geometry and functioning conditions on the seed's distribution accuracy. Moreover, observation of the seed's behaviour is done using a high-spe…
Dificultades de interpretación y de uso de los arrastres en Cabri 3d por estudiantes de E.S.O.
2012
La presente memoria corresponde al Trabajo Fin de Máster demandado dentro del programa del Máster de Investigación de Didácticas Específicas de la Universidad de Valencia. En este proyecto pretendemos contribuir a la mejora de la calidad docente a través de una mejor comprensión del aprendizaje en entornos colaborativos con programas de geometría dinámica. La aparición de programas de geometría dinámica en 3D (PGD 3D) ofrece la oportunidad de utilizarlos en el ámbito escolar. En este sentido, resulta pertinente hacerse las siguientes preguntas genéricas a partir de las cuales surgirán nuestras preguntas de investigación: § ¿Cuáles son la naturaleza y el alcance de la integración de PGD 3D e…
LA GEOMETRIE FRACTALE - UN NOUVEL OUTIL POUR EVALUER LE ROLE DE LA MORPHOLOGIE DES RESEAUX DE TRANSPORT PUBLIC DANS L'ORGANISATION SPATIALE DES AGGLO…
1998
National audience
Helicoid and Architectural application
2012
Questo articolo è un risultato parziale di una ricerca riguardante la rappresentazione di superfici complesse in geometria descrittiva. La padronanza e l’abilità nell’uso delle diverse tecniche di rappresentazione, consente di raggiungere risultati che altrimenti non sarebbero perseguibili. La Scuola di Disegno di Ingegneria, dell’Università di Palermo si è da sempre fatta promotrice della scienza della rappresentazione attraverso la sperimentazione di tecniche semplificative ed innovative della geometria descrittiva applicata all’architettura e all’ingegneria. In particolar modo, in questo lavoro, si riporta lo studio di una superficie complessa quale è l’elicoide che trova larga applicazi…
homogeneous embeddings of SL2(C) modulo a finite sub-group.
2000
L'objet de ce travail est l'étude des variétés algébriques normales complexes munies d'une action algébrique de $SL_{2}$ et qui contiennent $SL_{2}/H$ comme orbite ouverte, $H$ étant un sous-groupe fini de $SL_{2}$.Plus précisément on définit un plongement homogène de $SL_{2}/H$ comme la donnée d'une $SL_{2}$-variété irréductible $X$ (quasi-projective ou non) contenant $SL_{2}/H$ comme orbite ouverte et d'un morphisme $SL_{2}$-équivariant de $SL_{2}$ dans $X$.Les plongements homogènes lisses ainsi que les plongements minimaux (plongements lisses et complets qui ne sont pas des éclatements d'un autre plongement lisse complet) de $SL_{2}/\{Id\}$ et de $SL_{2}/\{\pm Id\}$ ont été déterminés pa…
Etude de certaines familles de variétés algébriques munies d'une action de groupe algébrique
2021
On the History of Differentiable Manifolds
2012
International audience; We discuss central aspects of history of the concept of an affine dif-ferentiable manifold, as a proposal confirming the need for using some quantitative methods (drawn from elementary Model Theory) in Mathematical Historiography. In particular, we prove that this geometric structure is a syntactic rigid designator in the sense of Kripke-Putnam.
Sentience and the Origins of Consciousness: From Cartesian Duality to Markovian Monism
2020
This essay addresses Cartesian duality and how its implicit dialectic might be repaired using physics and information theory. Our agenda is to describe a key distinction in the physical sciences that may provide a foundation for the distinction between mind and matter, and between sentient and intentional systems. From this perspective, it becomes tenable to talk about the physics of sentience and &lsquo
Equilibrium and structural studies of complexes with a hexadentate ligand containing amide, amine and pyridyl nitrogen donors. Crystal structures of …
2002
A novel potentially hexadentate ligand, 1,8-bis(2-pyridylcarbamoyl)-3,6-diazaoctane (pyctrien) has been synthesised as its tetrahydrochloride salt; its protonation constants and the stability constants of the copper(II) and nickel(II) chelates have been determined by potentiometry. Amide group deprotonation permits the formation of [MLH−1]+ and [MLH−2] species in all cases, whereas the detection of the neutral or the protonated species depends on the nature of the metal ions. The solid complexes of copper, nickel and cobalt with the neutral and the deprotonated ligand have been synthesised and characterised by IR and UV–VIS spectroscopy. The amidic groups are coordinated through the oxygen …
Monoamide Derivatives of EDTA Incorporating Pendent Carboxylates or Pyridyls: Synthesis, Metal Binding, and Crystal Structure of a Dinuclear Ca2+ Com…
2017
EDTA is a powerful, cheap and widely-used chelating unit for a large range of metal ions. To link it covalently to other molecules, the formation of an amide bond using one of the carboxylates is an attractive and simple approach, even though it may compromise metal ion binding as one of the four carboxylate donors is lost. Here we undertake a quantitative study of the metal ion binding of two new mono-amide derivatives of EDTA, namely AmGly1 and AmPy1, featuring an additional coordinating carboxylate or pyridyl group in the amide, respectively. The compounds are conveniently synthesised through alkylation of the tris-t-butyl ester of ethylenediamine-triacetic acid with the appropriate α-ch…