187,307 research outputs found
Relation between Backlund transformations and higher continuous symmetries of the Toda equation
No full textIn this paper we study one aspect of the continuous symmetries of the Toda equation. Namely, we establish a correspondence between Backlund transformations and continuous symmetries of the Toda equation. A symmetry transformation acting on a solution of the Toda equation can be seen as a superposition of Backlund transformations. Conversely, a Backlund transformation can be written, at least formally, as a composition of infinitely many higher symmetry transformations. This result reinforces the opinion that the presence of sufficiently many continuous symmetries for discrete equations is an indication of their integrability
Backlund transformations for the second Painleve hierarchy: a modified truncation approach
No full textThe second Painleve hierarchy is defined as the hierarchy of ordinary differential equations obtained by similarity reduction from the modified Korteweg-de Vries hierarchy. Its first member is the well known second Painleve equation, P-11. In this paper we use this hierarchy in order to illustrate our application of the truncation procedure in Painleve analysis to ordinary differential equations. We extend these techniques in order to derive auto-Backlund transformations for the second Painleve hierarchy. We also derive a number of other Backlund transformations, including a Backlund transformation onto a hierarchy of P-34 equations, and a little known Backlund transformation for P-11 itself. We then use our results on Backlund transformations to obtain, for each member of the P-11 hierarchy, a sequence of special integrals
Backlund transformations for the sl(2) Gaudin magnet
No full textElementary, one- and two-point, Backlund transformations are constructed for the generic case of the sl(2) Gaudin magnet. The spectrality property is used to construct these explicitly given, Poisson integrable maps which are time-discretizations of the continuous flows with any Hamiltonian from the spectral curve of the 2x2 Lax matrix
Barriers to Industrial Energy Efficiency in Foundries: a European Comparison
No full textAccording to recent studies, the 20% European improvement in energy efficiency will not be achieved with current trends, even with the adoption of present policies to reduce primary energy use. This is due to the existence of several barriers that hinder the adoption of the energy-efficient technologies and practices. A relevant contribution to improved energy efficiency could come from the industrial sector, due to its relevance on total energy use. This study therefore addresses barriers within the European foundry industry, a major industrial energy user and a strategic player for the European economy. The research investigates the barriers to energy efficiency at 65 foundries, several of them small and medium-sized enterprises (SMEs), highlighting the critical problems and difficulties by evaluating the socio-technical frameworks against which the barriers have been categorized. Findings show that the greatest perceived barriers are the perception of the lack of resources to be devoted to improving energy efficiency, and the existence of other priorities such as the importance of guaranteeing business continuity. The study has also performed a preliminary analysis of the factors that might affect the perception of barriers. In particular, looking at size, smaller enterprises show a greater perception of the barriers than larger ones, mainly due to several organizational issues, but with effect on behavioural ones, that tend to downgrade energy efficiency to a peripheral issue. The study has also highlighted differences by type of alloy characterizing foundries, taken as proxy of the process complexity. Indeed, enterprises with simpler production processes tend to perceive higher barriers to energy efficiency, showing the need to identify effective means to promote energy efficiency among those enterprises. Moreover, the analysis has pointed out that performing energy audits brings more awareness to the enterprises, highlighting the effective existing difficulties in improving their energy efficiency. This result seems to be relevant since it shows the need for the research to analyze the awareness to energy efficiency in greater depth and develop the most effective policies to increase it at industrial level. Finally when looking at the country in which foundries operate, German enterprises tend to suffer from the barriers far less than the average, whilst a totally different behaviour can be observed for Swedish ones. These preliminary findings open the research to investigate in greater depth the factors leading to a different perception of barriers, and also the domestic policies that have led to those results. Moreover, the study opens to investigate which means, i.e. drivers, might be more effectively exploited at European level to promote industrial energy efficiency
Backlund (O.). — Ueber die Bestimmung der Glieder langer Perioden mit besonderer Rücksicht auf die kleinen Planeten der Hecubagruppe. Backlund (O.). — Ueber eine horistische Differential gleichung Gyldéns. (Extraits du Bulletin de l’Académie de Saint-Pétersbourg, n°s 1 et 3, 1902.)
No full textCallandreau Octave. Backlund (O.). — Ueber die Bestimmung der Glieder langer Perioden mit besonderer Rücksicht auf die kleinen Planeten der Hecubagruppe. Backlund (O.). — Ueber eine horistische Differential gleichung Gyldéns. (Extraits du Bulletin de l’Académie de Saint-Pétersbourg, n°s 1 et 3, 1902.). In: Bulletin astronomique, tome 19, 1902. p. 471
Beyond Barriers – A Case Study on Driving Forces for Improved Energy Efficiency in the Foundry Industries in Finland, France, Germany, Italy, Poland, Spain, and Sweden
No full textEnergy management plays an important role in the transformation of industrial energy systems towards improved energy efficiency and increased sustainability. This paper aims to study driving forces for improved energy efficiency in some European energy-intensive foundry industries. The investigation has been conducted as a multiple case study involving 65 foundries located in Finland, France, Germany, Italy, Poland, Spain, and Sweden. The most relevant perceived driving forces were found to be financially related, followed by organizational driving forces. Nevertheless, some differences can be appreciated according to the firm's size and country. Almost half of the studied foundries lack a long-term energy strategy, about one-fourth stated that they have used Energy Performance Contracting (EPC), and only approximately one in ten foundries have used Third Party Financing (TPF). Among the studied foundries, three out of five have conducted an energy audit. On average, the energy saving potential according to the respondents is stated to be 7.5%. In conclusion, energy management in the European foundry industry, despite increasing energy prices and extensive energy policy actions taken by the EU, still seems to have great improvement potential, calling for future research and policy actions in the field
O. Backlund — Comet Encke, 1865-1885. Saint-Pétersbourg, 1886. In-4°
No full textR. R. O. Backlund — Comet Encke, 1865-1885. Saint-Pétersbourg, 1886. In-4°. In: Bulletin astronomique, tome 4, 1887. p. 242
Connection between the infinite sequence of Lie-Backlund symmetries of the Korteweg-de Vries and sine-Gordon equations
No full textFrom the observation that the infinite sequence of Lie-Backlund symmetries of the potential modified Kortweg-deVries (PMK-dV) and the sine-Gordon (s-G) equations are identical, it is shown that there exists a simple connection between the Lie-Backlund symmetries (written in the form of evolution equations) of the Korteweg-deVries (K-dV) and s-G equations. Further, this connection is similar to the one obtained by Chodos for the conserved quantities of K-dV and s-G equations. We also point out that the result of Chodos can be realized from the equality of conserved densities of PMK-dV and s-G systems
Supplemental Material - Attracting tomorrow’s leaders: Who joins political youth organisations for material reasons?
No full textSupplemental Material for Attracting tomorrow’s leaders: Who joins political youth organisations for material reasons? by Niklas Bolin, Anders Backlund, and Ann-Cathrine Jungar in Party Politics</p
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