| 64731. |
- Marciniak, Krzysztof, et al.
(författare)
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Separable systems of coordinates for triangular Newton equations q¨i = Mi(q1,..., qi)
- 2007
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Ingår i: Studies in applied mathematics (Cambridge). - : Wiley. - 0022-2526 .- 1467-9590. ; 118:1, s. 45-84
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Tidskriftsartikel (refereegranskat)abstract
- Triangular form of Newton equations is a strong property. Together with the existence of a single quadratic with respect to velocities integral of motion, it usally implies existence of further n - 1 integrals that are also quadratic. These integrals make the triangular system separable in new type of coordinates. The separation coordinates are built of quadric surfaces that are nonorthogonal and noconfocal and can intersect along lower dimensional singular manifolds. We present here separability theory for n-dimensional triangular systems and analyze the structure of separation coordinates in two and three dimensions. © 2007 by the Massachusetts Institute of Technology.
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| 64732. |
- Marciniak, Krzysztof, et al.
(författare)
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Separation of variables in quasi-potential systems of bi-cofactor form
- 2002
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Ingår i: Journal of Physics A. - : IOP Publishing. - 0305-4470 .- 1361-6447. ; 35:12, s. 2947-2964
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Tidskriftsartikel (refereegranskat)abstract
- We perform variable separation in the quasi-potential systems of equations of the form q¨ = -A-1?k = -à -1?k~, where A and à are Killing tensors, by embedding these systems into a bi-Hamiltonian chain and by calculating the corresponding Darboux-Nijenhuis coordinates on the symplectic leaves of one of the Hamiltonian structures of the system. We also present examples of the corresponding separation coordinates in two and three dimensions.
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| 64733. |
- Marciniak, Krzysztof, 1968-
(författare)
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Soliton Methods in the Theory of Integrable Mechanical Systems
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation is devoted to the study of integrable sets of mechanical equations with the use of soliton techniques. A Lax representation of the coupled Kortevegde Vries (cKdV) hierarchy with sow-ces is derived. It is shown that all stationary and restricted flows of the cKdV and the Harry Dym (HD) hierarchies admit a parametrization in the form of Newton equations. New infinite families of Newton equations are found and their integrable structures (such as Lax representation and bi-Hamiltonian formulation) are derived from the underlying soliton hierarchy. Next, an application of the r-matrix formalism to the theory of lattice integrable systems is presented. New families of lattice integrable systems are derived and several Miuralike maps between them are established. One of the offsprings of the obtained results is a completely new theory - theory of quasi-Lagrangian Newton (qLN) equations with two quadratic integrals of motion which contains as its special realization the classical separability theory for natural two-dimensional Hamiltonian systems. The theory of qLN systems goes however far beyond the separability theory - all qLN equations with two quadratic integrals of motion are characterized by a second order linear partial differential equation with polynomial coefficients of third order which generalizes the Bertrand-Darboux equation describing separable potentials in the plane. Hamiltonian formulation of the obtained qLN systems is presented and their complete integrability is proved. Finally, two families of Poisson structures are investigated. It is shown how these families naturally lead to separable systems or to quasi-Lagrangian Newton systems.
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| 64734. |
- Marciniec, A, et al.
(författare)
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Load Distribution in flexibly Supported Three-Row Roller Slew Bearings
- 1994
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Ingår i: Tribology Transactions. - : Informa UK Limited. - 1040-2004 .- 1547-397X. ; 37:4, s. 757-762
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Tidskriftsartikel (refereegranskat)abstract
- In general, slew bearings are less firmly supported by their mounting structures than small bearings. Hence, the load distribution around the bearing may be vastly different than that predicted by classic bearing formulas. The finite element method has been employed to determine load distribution in a three-row roller slew bearing mounted between two flexible, ring shaped supporting structures composed of beam elements. A special bar element modeling the system of two opposite rollers in contact with its raceways has been elaborated. The influence of the nonlinear force displacement characteristics of each of the rollers, as well as the influence of gaps between the rollers and its raceways have been taken into account. The nonlinear contact problem has been solved utilizing the Newton-Raphson method with continually updated stiffness matrix due to both element nonlinearity and contact status. The effect of a number of design parameters on the load distribution has been investigated.
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| 64735. |
- Marco-Almagro, Lluis, et al.
(författare)
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Segmentation in Kansei Engineering Studies Based on the Emotional Response
- 2018
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Ingår i: Proceedings KEER2018, Go Green with Emotion. 7th International Conference on Kansei Engineering & Emotion Research 2018, 19-22 March 2018, Kuching, Malaysia. - Linköping : Linköping University Electronic Press. - 9789176853146 ; , s. 231-238
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Konferensbidrag (refereegranskat)abstract
- Socioeconomic and demographic data of participants are often collected when performing a Kansei Engineering study for stratification purposes. This paper offers an alternative stratification procedure, directly based on the emotional response that participants give to prototypes. This approach can deliver groups that are more meaningful for the Kansei Engineering study. Socioeconomic and demographic data (among other kinds of data) can then be used to characterize the obtained emotional groups.
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| 64736. |
- Marco, Barbero, et al.
(författare)
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Determining the level of cervical radiculopathy : Agreement between visual inspection of pain drawings and magnetic resonance imaging
- 2023
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Ingår i: Pain Practice. - : Wiley. - 1530-7085 .- 1533-2500. ; 23:1, s. 32-40
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims Pain drawings are commonly used in the clinical assessment of people with cervical radiculopathy. This study aimed to assess (1) the agreement of clinical interpretation of pain drawings and MRI findings in identifying the affected level of cervical radiculopathy, (2) the agreement of these predictions based on the pain drawing among four clinicians from two different professions (i.e., physiotherapy and surgery) and (3) the topographical pain distribution of people presenting with cervical radiculopathy (C4-C7). Methods Ninety-eight pain drawings were obtained from a baseline assessment of participants in a randomized clinical trial, in which single-level cervical radiculopathy was determined using MRI. Four experienced clinicians independently rated each pain drawing, attributing the pain distribution to a single nerve root (C4-C7). A post hoc analysis was performed to assess agreement. Outcome measures Percentage agreement and kappa values were used to assess the level of agreement. Topographic pain frequency maps were created for each cervical radiculopathy level as determined by MRI. Results The radiculopathy level determined from the pain drawings showed poor overall agreement with MRI (mean = 35.7%, K = -0.007 to 0.139). The inter-clinician agreement ranged from fair to moderate (K = 0.212-0.446). Topographic frequency maps revealed that pain distributions were widespread and overlapped markedly between patients presenting with different levels cervical radiculopathy. Conclusion This study revealed a lack of agreement between the segmental level affected determined from the patients pain drawing and the affected level as identified on MRI. The large overlap of pain and non-dermatomal distribution of pain reported by patients likely contributed to this result.
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| 64737. |
- Marco, Kupiainen, et al.
(författare)
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GPU-acceleration of A High Order Finite Difference Code Using Curvilinear Coordinates
- 2020
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Ingår i: Proceedings of the 2020 International Conference on Computing, Networks and Internet of Things. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450377713 ; , s. 41-47
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Konferensbidrag (refereegranskat)abstract
- GPU-accelerated computing is becoming a popular technology due to the emergence of techniques such as OpenACC, which makes it easy to port codes in their original form to GPU systems using compiler directives, and thereby speeding up computation times relatively simply. In this study we have developed an OpenACC implementation of the high order finite difference CFD solver ESSENSE for simulating compressible flows. The solver is based on summation-by-part form difference operators, and the boundary and interface conditions are weakly implemented using simultaneous approximation terms. This case study focuses on porting code to GPUs for the most time-consuming parts namely sparse matrix vector multiplications and the evaluations of fluxes. The resulting OpenACC implementation is used to simulate the Taylor-Green vortex which produces a maximum speed-up of 61.3 on a single V100 GPU by compared to serial CPU version.
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| 64738. |
- Marco-Ramell, Anna, et al.
(författare)
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Proteomics and the search for welfare and stress biomarkers in animal production in the one health context
- 2016
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Ingår i: Molecular Biosystems. - : Royal Society of Chemistry. - 1742-206X .- 1742-2051. ; 12:7, s. 2024-2035
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Forskningsöversikt (refereegranskat)abstract
- Stress and welfare are important factors to animal production in a context of growing production optimization and scrutiny by the general public. In a context in which animal and human health are intertwined aspects of the one-health concept it is of utmost importance to define markers for stress and welfare. These are important tools for producers, retailers, regulatory agents and ultimately consumers to effectively monitor and assess the welfare state of production animals. Proteomics is the science that studies the proteins existing in a given tissue or fluid. In this review we address this topic by showing clear examples where proteomics has been used to study stress-induced changes at various levels. We adopt a multi-species (cattle, swine, small ruminants, poultry, fish and shellfish) approach under the effect of varied stress inducers (handling, transport, management, nutritional, thermal and exposure to pollutants) clearly demonstrating how Proteomics and Systems Biology are key elements to the study of stress and welfare on farm animals and a powerful tool to animal welfare, health and productivity.
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| 64739. |
- Marconi, L., et al.
(författare)
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The SHERPA project : Smart collaboration between humans and ground-aerial robots for improving rescuing activities in alpine environments
- 2012
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Ingår i: Proc. of the IEEE Int. Workshop on Safety, Security and Rescue Robotics (SSRR). - : IEEE. - 9781479901647 - 9781479901630 - 9781479901654 ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- The goal of the paper is to present the foreseen research activity of the European project “SHERPA” whose activities will start officially on February 1th 2013. The goal of SHERPA is to develop a mixed ground and aerial robotic platform to support search and rescue activities in a real-world hostile environment, like the alpine scenario that is specifically targeted in the project. Looking into the technological platform and the alpine rescuing scenario, we plan to address a number of research topics about cognition and control. What makes the project potentially very rich from a scientific viewpoint is the heterogeneity and the capabilities to be owned by the different actors of the SHERPA system: the human rescuer is the “busy genius”, working in team with the ground vehicle, as the “intelligent donkey”, and with the aerial platforms, i.e. the “trained wasps” and “patrolling hawks”. Indeed, the research activity focuses on how the “busy genius” and the “SHERPA animals” interact and collaborate with each other, with their own features and capabilities, toward the achievement of a common goal.
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| 64740. |
- Marcos Celada, Lukas, et al.
(författare)
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Fully Bio‐Based Ionic Liquids for Green Chemical Modification of Cellulose in the Activated‐State
- 2023
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Ingår i: ChemSusChem. - 1864-5631 .- 1864-564X. ; 17:3
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Tidskriftsartikel (refereegranskat)abstract
- Biopolymers, especially cellulose, are vital to transitioning to a circular economy and reducing our reliance on fossil fuels. However, for many applications a high degree of cellulose hydroxyl modification is necessary. The challenge is that the chemical features of the hydroxyls of cellulose and water are similar. Therefore, chemical modification of cellulose is often explored under non-aqueous conditions with systems that result in high hydroxyl accessibility and reduce cellulose aggregation. Unfortunately, these systems depend on hazardous and complex solvents from fossil resources, which diverge from the initial sustainability objectives. To address this, we developed three new betaine-based ionic liquids that are fully bio-based, scalable, and green. We found that a specific ionic liquid had the perfect chemical features for the chemical activation of cellulose without disturbing its crystalline ordering. The high activation in heterogeneous conditions was exemplified by reacting cellulose with succinic anhydride, resulting in more than 30 % conversion of all hydroxyls on cellulose. Overall, this work opens new perspectives for the derivatization of cellulosic materials while simultaneously “keeping it green”.
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