Search results for "Force density"

showing 4 items of 4 documents

A gradient elasticity theory for second-grade materials and higher order inertia

2012

Abstract Second-grade elastic materials featured by a free energy depending on the strain and the strain gradient, and a kinetic energy depending on the velocity and the velocity gradient, are addressed. An inertial energy balance principle and a virtual work principle for inertial actions are envisioned to enrich the set of traditional theoretical tools of thermodynamics and continuum mechanics. The state variables include the body momentum and the surface momentum, related to the velocity in a nonstandard way, as well as the concomitant mass-accelerations and inertial forces, which do intervene into the motion equations and into the force boundary conditions. The boundary traction is the …

Angular momentummedia_common.quotation_subjectTraction (engineering)Continuum thermodynamicsInertiaMaterials Science(all)Modelling and SimulationWave dispersionGeneral Materials ScienceVirtual workBoundary value problemmedia_commonMathematicsContinuum mechanicsForce densityMechanical EngineeringApplied MathematicsMathematical analysisEquations of motionCondensed Matter PhysicsDynamicsGradient elasticityClassical mechanicsHigher order inertiaMechanics of MaterialsModeling and SimulationInternational Journal of Solids and Structures
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Casimir-Polder force density between an atom and a conducting wall

2007

In this paper we calculate the Casimir-Polder force density (force per unit area acting on the elements of the surface) on a metallic plate placed in front of a neutral atom. To obtain the force density we use the quantum operator associated to the electromagnetic stress tensor. We explicitly show that the integral of this force density over the plate reproduces the total force acting on the plate. This result shows that, although the force is obtained as a sum of surface element-atom contributions, the stress-tensor method includes also nonadditive components of Casimir-Polder forces in the evaluation of the force acting on a macroscopic object.

Body forcePhysicsQuantum PhysicsNormal forceForce densityVan der Waals interactionElectrostatic force microscopeSurface forceFOS: Physical sciencesAtom-surface interactionAtomic and Molecular Physics and OpticsClassical mechanicsCentral forceQuantum electrodynamicsFluctuationsQuantum Physics (quant-ph)Conservative forceResultant force
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A polynomial algorithm solving a special class of hybrid optimal control problems

2006

Hybrid optimal control problems are, in general, difficult to solve. A current research goal is to isolate those problems that lead to tractable solutions [5]. In this paper, we identify a special class of hybrid optimal control problems which are easy to solve. We do this by using a paradigm borrowed from the Operations Research field. As main result, we present a solution algorithm that converges to the exact solution in polynomial time. Our approach consists in approximating the hybrid optimal control problem via an integer-linear programming reformulation. The integer-linear programming problem is a Set-covering one with a totally unimodular constraint matrix and therefore solving the S…

EngineeringMathematical optimizationForce densityComputational complexity theoryLinear programmingbusiness.industrySpecial classOptimal controlPolynomial algorithmControllabilityHybrid optimal controlAlgorithmsHybrid computersInteger programmingLinear control systemsUnimodular matrixControl theoryHuman machine interactionLocal search (optimization)Relaxation (approximation)Settore MAT/09 - Ricerca OperativabusinessInteger programmingTime complexityMathematics2006 IEEE Conference on Computer Aided Control System Design, 2006 IEEE International Conference on Control Applications, 2006 IEEE International Symposium on Intelligent Control
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Design Considerations of Transverse Flux Generator to Sea Wave Energy

2014

In this paper we study the possibility to use a transverse flux linear generator (TFG) because transverse flux technology presents the highest force density per volume index among the iron based electrical machines. This paper is organized as follows an introduction to describe "state of the art" of WEC's and TFG, in the Section II we find a summary description of the marine condition of the chosen site; in the Section III there is an the analytical procedure for geometric and magnetic design of device (chosen material, length, etc) and in the Section IV the simulation of generator. Further defined the design of the generator, the machine was designed and analyzed through the use of a 3D FE…

SEAwave energyEngineeringGenerator (computer programming)electrical machines.Force densitybusiness.industryMagnetic separationMechanical engineeringSettore ING-IND/32 - Convertitori Macchine E Azionamenti ElettriciFinite element methodSoftwareSection (archaeology)Linear congruential generatorbusinesstransverse fluxEnergy (signal processing)
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