789 research outputs found
Conservation Laws, Hodograph Transformation and Boundary Value Problems of Plane Plasticity
No full textFor the hyperbolic system of quasilinear first-order partial differential equations, linearizable by hodograph transformation, the conservation laws are used to solve the Cauchy problem. The equivalence of the initial problem for quasilinear system and the problem for conservation laws system permits to construct the characteristic lines in domains, where Jacobian of hodograph transformations is equal to zero. Moreover, the conservation laws give all solutions of the linearized system. Some examples from the gas dynamics and theory of plasticity are considered
Reproduction of solutions of bidimensional ideal plasticity
No full textThe symmetries of a system of differential equations allowed the transformation of its solutions to a solution of this system. New analytical exact solutions of a system of two-dimensional ideal plasticity equations were constructed from two well-known solutions, that for a circular cavity stressed by normal pressure, and Prandtl's solution for a block compressed between perfectly rough plates, for the case where the thickness of the block was rather small. A mechanical sense of new solutions was discussed. � 2007 Elsevier Ltd. All rights reserved
Spanish version of the eating attitudes test 40: Dimensionality, reliability, convergent and criterion validity
No full textIn this paper, all the known classical solutions of a plane perfect plasticity system under the Saint Venant-Tresca-von Mises yield criterion are associated with some group of point symmetries. The equations of slip-line families for all solutions are constructed, which allows one to explicitly determine the boundaries of the plastic areas. It is shown how one can determine the compatible velocity solution for known stresses by considering symmetries. Some invariant solutions of velocities for Prandtl stresses are constructed. The mechanical sense of the obtained velocity fields is discussed. To the blessed memory of our teacher D D Ivlev " 2013 IOP Publishing Ltd.",,,,,,"10.1088/1751-8113/46/35/355202",,,"http://hdl.handle.net/20.500.12104/44653","http://www.scopus.com/inward/record.url?eid=2-s2.0-84882345659&partnerID=40&md5=98ef75f12d0fb9f69bf5894711a3b1bf",,,,,,"35",,"Journal of Physics A: Mathematical and Theoretical",,,,"46",,"Scopu
Some symmetry group aspects of a perfect plane plasticity system
No full textIn this paper, all the known classical solutions of a plane perfect plasticity system under the Saint Venant-Tresca-von Mises yield criterion are associated with some group of point symmetries. The equations of slip-line families for all solutions are constructed, which allows one to explicitly determine the boundaries of the plastic areas. It is shown how one can determine the compatible velocity solution for known stresses by considering symmetries. Some invariant solutions of velocities for Prandtl stresses are constructed. The mechanical sense of the obtained velocity fields is discussed. To the blessed memory of our teacher D D Ivlev © 2013 IOP Publishing Ltd
Deformation of characteristic curves of the plane ideal plasticity equations by point symmetries
No full textThe hyperbolic system of plane ideal plasticity equations under the Saint-Venant-Mises' yield criterion is considered. Its' characteristics curves are deformed by the action of admitted group of point transformations, that permits to construct a new analytical solution. The mechanical sense of obtained characteristic fields is discussed. The general algorithm of the relation of solutions of quasilinear hyperbolic system of two homogeneous equations of two independent variables is proposed. © 2009 Elsevier Ltd. All rights reserved
Decomposing diversity patterns of a soft-bottom macroinvertebrate community in the tropical eastern Pacific
No full textThe hyperbolic system of plane ideal plasticity equations under the Saint-Venant-Mises' yield criterion is considered. Its' characteristics curves are deformed by the action of admitted group of point transformations, that permits to construct a new analytical solution. The mechanical sense of obtained characteristic fields is discussed. The general algorithm of the relation of solutions of quasilinear hyperbolic system of two homogeneous equations of two independent variables is proposed. " 2009 Elsevier Ltd. All rights reserved.",,,,,,"10.1016/j.na.2009.01.161",,,"http://hdl.handle.net/20.500.12104/40505","http://www.scopus.com/inward/record.url?eid=2-s2.0-72149121546&partnerID=40&md5=8de203f29b83be3231bd87d42e928ab6",,,,,,"12",,"Nonlinear Analysis, Theory, Methods and Applications",,"e127
Lie - Backlund symmetries of homogeneous system of bi-dimensional equations
No full textThe framework of generalized (Lie-Backlund) symmetries is used to analyze a general homogeneous hyperbolic system of bi-dimensional quasilinear equations. The symmetries of the first order are constructed and the theorem of the existence of the generalized symmetries is formulated. As example, we consider the spatially one-dimensional time dependent system of equations, which describes the gravity-driven free surface flow of granular avalanches
Lie - Backlund symmetries of homogeneous system of bi-dimensional equations
No full textThe framework of generalized (Lie-Backlund) symmetries is used to analyze a general homogeneous hyperbolic system of bi-dimensional quasilinear equations. The symmetries of the first order are constructed and the theorem of the existence of the generalized symmetries is formulated. As example, we consider the spatially one-dimensional time dependent system of equations, which describes the gravity-driven free surface flow of granular avalanches
The integration of environmental and social sustainability impacts of the biojet fuel product system within the life cycle assessment framework
No full textThe Master's programme Industrial Ecology is jointly organised by Leiden University and Delft University of Technology - Biojet fuel is developed as a potentially more sustainable alternative to existing petroleum based jet fuels. To establish the environmental and social sustainability of the biojet fuel product system, the full life cycle of the production should be analyzed. The environmental LCA (ELCA)and social LCA (SLCA) have been developed as two independent tools, but they cannot be used to analyze the same product system as their system boundaries differ. This research studies the possibility of harmonizing the two tools into a single social and environmental LCA (SELCA) methodology in light of its use in the biojet fuel product system. SELCA was developed through an extensive literature review, followed by catering it to the biojet fuel product system based on a survey and a dummy case study. The ELCA is based on unit processes while the SLCA uses organizations as its base. To reconcile these two system elements, the organizations were treated as multifunctional processes that can be allocated to the product system. The DPSIR model was used to ensure that data on interventions and economic flows were equivalent to each other and capable of being causally connected to the product system. The resulting methodology has consistent system boundaries and data for both social and environmental impacts. The majority of existing SLCA characterization methods and indicators are not compatible with SELCA. Indicators must be based on DPSIR pressure level data and be capable of being aggregated for the product system in order to be comparable to ELCA indicators. Many SLCA methodologies are based on statistical data which conceptually cannot be attributed to a particular organization or unit process. The only operational methodology is that of Hunkeler (2006) which uses quantitative labor hour data. As a methodology for assessing the biojet fuel, SELCA has several limits. The existing indicators do not address all issues considered important by academia and the industry. Also, despite that SELCA can in principle include the full biojet product system, in practice it will be limited by the lack of background databases. This results in more cut-off points and smaller system boundaries as shown in the dummy case study. However, with further research and development of characterization methods and databases, SELCA has the potential to fully integrate the environmental and social impact assessments of the biojet fuel product system.Technology, Policy and ManagementEngineering, Systems and ServicesIndustrial Ecolog
- …
