954 resultados para Eigenfunctions and fundamental solution


Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this thesis the molecular level design of functional materials and systems is reported. In the first part, tetraphosphonate cavitand (Tiiii) recognition properties towards amino acids are studied both in the solid state, through single crystal X-ray diffraction, and in solution, via NMR and ITC experiments. The complexation ability of these supramolecular receptors is then applied to the detection of biologically remarkable N-methylated amino acids and peptides using complex dynamic emulsions-based sensing platforms. In the second part, a general supramolecular approach for surface decoration with single-molecule magnets (SMMs) is presented. The self-assembly of SMMs is achieved through the formation of a multiple hydrogen bonds architecture (UPy-NaPy complexation). Finally we explore the possibility to impart auxetic behavior to polymeric material through the introduction of conformationally switchable monomers, namely tetraquinoxaline cavitands (QxCav). Their interconversion from a closed vase conformation to an extended kite form is studied first in solution, then in polymeric matrixes via pH and tensile stimuli by UV-Vis spectroscopy.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this work, new coordination polymers based on two different classes of synthons are presented. In addition, manganese-based metallacrowns of magnetic interest are studied, both in the solid state and in solution. Firstly, functionalized bispyrazolylmethane derivatives are employed as bridging ligands for the establishment of silver-based coordination polymers; the influence of the substituent groups and of the counterions on the supramolecular packing is also investigated. Secondly, the use of metallacrown (MC) complexes as building blocks for porous coordination polymers is discussed. The design of a new metallacrown species is presented, which shows the tendency of aggregating in the solid state to form coordination polymers. Two new coordination polymers are indeed reported, of which one is the first MC-based permanently porous coordination network ever presented. The solid resists solvent evacuation and exhibits gas uptake ability. Furthermore, the isolation and characterization of a new metallacryptate species based on manganese ions is described. The metal-rich structure comprises nine Mn(II)/Mn(III) ions and presents an inverse metallacrown core subunit that binds a μ3-O2- ion. The metallacryptate is isolated in high yields and stable in solution. Lastly, a family of 3d-4f heterometallic metallacrowns is characterized in solution by means of UV-Vis spectrophotometry and of paramagnetically shifted 1H-NMR. The lanthanide-induced shifts observed in the spectra are employed to describe the molecules behaviour in solution and are qualitatively related to the magnetic properties of the compounds.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the last decade, phosphonate and quinoxaline cavitand have been extensively studied, highlighting their outstanding recognition properties. Their successful applications in material science and sensing open the way to new potential applications, such as border security, environmental monitoring and chiral recognition. The present thesis explores the recognition properties of phosphonate and quinoxaline cavitands towards new targets, for molecular recognition and sensing applications. Chapter 2 highlights the enantioselective behavior of phosphonate cavitands towards chiral guests in the solid state and in solution. Phosphonate cavitands were exploited for the molecular recognition of L-lactic acid (chapter 3), a widespread natural molecule which offer multiple potential applications, and a human sweat marker used for the detection of human presence (chapter 4). The second part is devoted to sensing applications of quinoxaline cavitands. Chapter 5 describes the use of QxCav for the preconcentration of drugs precursors, while chapter 6 reports the design, synthesis and grafting of a rigidified EtQxBox on a silicon wafer.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The present thesis is focused on the development of a thorough mathematical modelling and computational solution framework aimed at the numerical simulation of journal and sliding bearing systems operating under a wide range of lubrication regimes (mixed, elastohydrodynamic and full film lubrication regimes) and working conditions (static, quasi-static and transient conditions). The fluid flow effects have been considered in terms of the Isothermal Generalized Equation of the Mechanics of the Viscous Thin Films (Reynolds equation), along with the massconserving p-Ø Elrod-Adams cavitation model that accordingly ensures the so-called JFO complementary boundary conditions for fluid film rupture. The variation of the lubricant rheological properties due to the viscous-pressure (Barus and Roelands equations), viscous-shear-thinning (Eyring and Carreau-Yasuda equations) and density-pressure (Dowson-Higginson equation) relationships have also been taken into account in the overall modelling. Generic models have been derived for the aforementioned bearing components in order to enable their applications in general multibody dynamic systems (MDS), and by including the effects of angular misalignments, superficial geometric defects (form/waviness deviations, EHL deformations, etc.) and axial motion. The bearing exibility (conformal EHL) has been incorporated by means of FEM model reduction (or condensation) techniques. The macroscopic in fluence of the mixedlubrication phenomena have been included into the modelling by the stochastic Patir and Cheng average ow model and the Greenwood-Williamson/Greenwood-Tripp formulations for rough contacts. Furthermore, a deterministic mixed-lubrication model with inter-asperity cavitation has also been proposed for full-scale simulations in the microscopic (roughness) level. According to the extensive mathematical modelling background established, three significant contributions have been accomplished. Firstly, a general numerical solution for the Reynolds lubrication equation with the mass-conserving p - Ø cavitation model has been developed based on the hybridtype Element-Based Finite Volume Method (EbFVM). This new solution scheme allows solving lubrication problems with complex geometries to be discretized by unstructured grids. The numerical method was validated in agreement with several example cases from the literature, and further used in numerical experiments to explore its exibility in coping with irregular meshes for reducing the number of nodes required in the solution of textured sliding bearings. Secondly, novel robust partitioned techniques, namely: Fixed Point Gauss-Seidel Method (PGMF), Point Gauss-Seidel Method with Aitken Acceleration (PGMA) and Interface Quasi-Newton Method with Inverse Jacobian from Least-Squares approximation (IQN-ILS), commonly adopted for solving uid-structure interaction problems have been introduced in the context of tribological simulations, particularly for the coupled calculation of dynamic conformal EHL contacts. The performance of such partitioned methods was evaluated according to simulations of dynamically loaded connecting-rod big-end bearings of both heavy-duty and high-speed engines. Finally, the proposed deterministic mixed-lubrication modelling was applied to investigate the in fluence of the cylinder liner wear after a 100h dynamometer engine test on the hydrodynamic pressure generation and friction of Twin-Land Oil Control Rings.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper assesses the uses and misuses in the application of the European Arrest Warrant (EAW) system in the European Union. It examines the main quantitative results of this extradition system achieved between 2005 and 2011 on the basis of the existing statistical knowledge on its implementation at EU official levels. The EAW has been anchored in a high level of ‘mutual trust’ between the participating states’ criminal justice regimes and authorities. This reciprocal confidence, however, has been subject to an increasing number of challenges resulting from its practical application, presenting a dual conundrum: 1. Principle of proportionality: Who are the competent judicial authorities cooperating with each other and ensuring that there are sufficient impartial controls over the necessity and proportionality of the decisions on the issuing and execution of EAWs? 2. Principle of division of powers: How can criminal justice authorities be expected to handle different criminal judicial traditions in what is supposed to constitute a ‘serious’ or ‘minor’ crime in their respective legal settings and ‘who’ is ultimately to determine (divorced from political considerations) when is it duly justified to make the EAW system operational? It is argued that the next generation of the EU’s criminal justice cooperation and the EAW need to recognise and acknowledge that the mutual trust premise upon which the European system has been built so far is no longer viable without devising new EU policy stakeholders’ structures and evaluation mechanisms. These should allow for the recalibration of mutual trust and mistrust in EU justice systems in light of the experiences of the criminal justice actors and practitioners having a stake in putting the EAW into daily effect. Such a ‘bottom-up approach’ should be backed up with the best impartial and objective evaluation, an improved system of statistical collection and an independent qualitative assessment of its implementation. This should be placed as the central axis of a renewed EAW framework which should seek to better ensure the accountability, impartial (EU-led) scrutiny and transparency of member states’ application of the EAW in light of the general principles and fundamental rights constituting the foundations of the European system of criminal justice cooperation.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Schengen Visa liberalisation in the Eastern Partnership countries, Russia and Turkey has proven to have a huge transformative potential across the justice, liberty and security policies of the countries where it has been deployed. Far-reaching technical reforms in the fields of document security, irregular migration and border management, public order security and fundamental rights have to be implemented so that visa-free travel can be allowed. Evidence provided by visa applications data reveals that visa liberalisation is a logical step, provided that the technical reforms are adopted and implemented. This study analyses the current state of play of the implementation of the EU visa policy instruments and assesses the positive impact of visa-free travel on trans-border mobility according to current visa application statistics.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The European Central Bank’s Outright Monetary Transactions (OMT) programme was a politically-pragmatic tool to diffuse the euro-area crisis. But it did not deal with the fundamental incompleteness of the European monetary union. As such, it blurred the boundary between monetary and fiscal policy. The fuzziness of this boundary helped in the short-term but pushed political and economic risks to the future. Unless a credible commitment to enforcing losses on private creditors is instituted, these conundrums will persist. The German Federal Constitutional Court has helped by insisting that such a dialogue be conducted in order to achieve a more durable political and economic solution. A study of the European Union Court of Justice’s Pringle decision (Thomas Pringle v Government of Ireland, Ireland and The Attorney General, Case C-370/12, ECJ, 27 November 2012) suggests that the ECJ will also not rubber-stamp the OMT – and, if it does, the legal victory will not resolve the fundamental dilemmas.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper was prepared as a ILEC Policy Brief for discussion at the final conference of the project on Involuntary Loss of European Citizenship: Exchanging Knowledge and Identifying Guidelines for Europe, 11-12 December 2014. Co-funded by the European Commission’s DG for Justice, Citizenship and Fundamental Rights, the ILEC project has aimed to establish a framework for debate on international norms on involuntary loss of nationality. For more information visit: www.ilecproject.eu.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper was prepared as a Policy Brief for discussion at the final conference of the project on Involuntary Loss of European Citizenship: Exchanging Knowledge and Identifying Guidelines for Europe, 11-12 December 2014. Co-funded by the European Commission’s DG for Justice, Citizenship and Fundamental Rights, the ILEC project has aimed to establish a framework for debate on international norms on involuntary loss of nationality. For more information visit: www.ilecproject.eu.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper was prepared as a Policy Brief for discussion at the final conference of the project on Involuntary Loss of European Citizenship: Exchanging Knowledge and Identifying Guidelines for Europe, 11-12 December 2014. Co-funded by the European Commission’s DG for Justice, Citizenship and Fundamental Rights, the ILEC project has aimed to establish a framework for debate on international norms on involuntary loss of nationality. For more information visit: www.ilecproject.eu.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper was prepared as a Policy Brief for discussion at the final conference of the project on Involuntary Loss of European Citizenship: Exchanging Knowledge and Identifying Guidelines for Europe, 11-12 December 2014. Co-funded by the European Commission’s DG for Justice, Citizenship and Fundamental Rights, the ILEC project has aimed to establish a framework for debate on international norms on involuntary loss of nationality. For more information visit: www.ilecproject.eu.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper, the third in a series for a CEPS project on the ‘The British Question’, is pegged on an ambitious exercise by the British government to review all the competences of the European Union on the basis of evidence submitted by independent stakeholders. The reviews considered in this paper cover the following EU policies: the single market for services, financial markets, the free movement of people, cohesion, energy, agriculture, fisheries, competition, social and employment policies, and fundamental rights. The declared objective of Prime Minister Cameron is to secure a ‘new settlement’ between the UK and the EU. From political speeches in the UK one can identify three different types of possible demand: reform of EU policies, renegotiation of the UK’s specific terms of membership, and repatriation of competences from the EU back to the member states. As most of the reviews are now complete, three points are becoming increasingly clear: i) The reform agenda – past, present or future - concerns virtually every branch of EU policy, including several cases reviewed here that are central to stated UK economic interests. The argument that the EU is ‘unreformable’ is shown to be a myth. ii) The highly sensitive cases of immigration from the EU and social policies may translate into requests for renegotiation of specific conditions for the UK, but further large-scale opt-outs, as in the case of the euro and justice and home affairs, are implausible. iii) While demands for repatriation of EU competences are voiced in general terms in public debate in the UK, no specific proposals emerge from the evidence as regards competences at the level at which they are identified in the treaties, and there is no chance of achieving consensus for such ideas among member states. Michael Emerson and Steven Blockmans, “British Balance of Competence Reviews, Part I: ‘Competences about right, so far’”, CEPS/EPIN Working Paper No. 35, October 2013 (www.ceps.eu/book/british-balance-competence-reviews-part-i-%E2%80%98competences-about-right-so-far%E2%80%99)(http://aei.pitt.edu/45599/); Michael Emerson, Steven Blockmans, Steve Peers and Michael Wriglesworth, “British Balance of Competence Reviews, Part II: Again, a huge contradiction between the evidence and Eurosceptic populism”, CEPS/EPIN Working Paper No. 40, June 2014 (www.ceps.eu/book/british-balance-competence-reviews-part-ii-again-huge-contradiction-between-evidence-and-eurosc)(http://aei.pitt.edu/52452/).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The Riga Summit of 21-22 May reaffirmed the EU’s commitment to the Eastern Partnership, underlined further differentiation between the neighbours and reiterated the importance of people-to-people contacts, finds Hrant Kostanyan in this CEPS Commentary. All in all, however, the Summit was more of a stocktaking exercise than a momentous redefinition of relations with the EU at a time of precarious geopolitics in the east. Politically, it is important now for the EU to defend what it already offered to the eastern neighbours and reconfirm the Eastern Partnership as a defining feature of its foreign policy and fundamental to the EU’s larger Security Strategy review.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

What is happening to the Schengen borders? Is Schengen in ‘crisis’? This paper examines the state of play in the Schengen system in light of the developments during 2015. It critically examines the assertion that Schengen is ‘in crisis’ and seeks to set the record straight on what has been happening to the intra-Schengen border-free and common external borders system. The paper argues that Schengen is here to stay and that reports about the reintroduction of internal border checks are exaggerated as they are in full compliance with the EU rule of law model laid down in the Schengen Borders Code and subject to scrutiny by the European Commission. It also examines the legal challenges inherent to police checks within the internal border areas as having an equivalent effect to border checks as well as the newly adopted proposal for a European Border and Coast Guard system. The analysis shows that the most far-reaching challenge to the current and future configurations of EU border policies relates to ensuring that they are in full compliance with fundamental human rights obligations to refugees, effective accountability and independent monitoring of the implementation of EU legal standards. This should be accompanied by a transparent and informed discussion on which ‘Schengen’ and which 'common European Border and Coast Guard Agency' we exactly want within current democratic rule of law and fundamental rights remits.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Two very different cases decided by the European Court of Human Rights illustrate how the non-availability of sufficient reasons, for pre-trial judicial decisions in one case, and for a decision in a civil and administrative matter in the other, can lead to due process violations in terms of Articles 5 or 6 of the Convention of Human Rights and Fundamental Freedoms.