6,802 research outputs found
Generation type inequalities for closed linear operators related to domains with conical points
No full textLet be a second-order linear differential operator in divergence form. We prove that the operator , where λ ∈ C and I stands for the identity operator, is closed and injective when Re λ is large enough and the domain of consists of a special class of weighted Sobolev function spaces related to conical open bounded sets of Rn, n ≥ 1
The effect of swingarm stiffness on motorcycle stability: Experimental measurements and numerical simulations
No full textThis paper focuses on the effect of swingarm deformability on motorcycle stability and in particular on the weave mode. Multibody models for the analysis of stability and handling of single track vehicles require a lumped element representation of the deformability of the critical structural elements of the vehicle. The twist axis method is used to identify lumped stiffness and damping elements able to represent bending and torsion deformability of the swingarm. Experimental tests and identification results dealing with two different swingarms are presented. The identified lumped stiffness and damping elements are implemented in a multibody code and some numerical stability analyses are carried out. Calculated results show that swingarm deformability has a small effect on the stability of super sport motorcycles, whereas the stability of the weave mode of enduro motorcycles is affected by swingarm deformability in a specific range of speeds
A doe approach for evaluating the effect of bicycle properties on stability
No full textThe effect on stability of mass, geometric and stiffness parameters of a bicycle with compliant frame, fork and wheel is studied. Critical stiffnesses of the structural elements are identified by means of specific experimental tests based on modal analysis and static stiffness measurement. Numerical stability analysis is carried out by means of a MATLAB code and simulations are planned with the design of experiment (DOE) approach. Numerical results show that the rigid body properties that have the main influence on self-stability are front wheel radius, longitudinal position of the center of mass and trail. Compliance of structural elements has a small effect on self-stability, but causes the appearance of a wobble mode that may be unstable at high speed
Parametric analysis of the stability of a bicycle taking into account geometrical, mass and compliance properties
No full textSome studies of bicycle dynamics have applied the Whipple
Carvallo bicycle model (WCBM) for the stability analysis. The WCBM is
limited, since structural elements are assumed to be rigid bodies. In this paper,
the WCBM is extended to include the front assembly lateral compliance,
and analysis focuses on the study of the open loop stability of a benchmark
bicycle. Experimental tests to identify fork and wheel properties are performed,
this data is used in the stability analysis for ranking the influence of design
parameters. Indexes from the eigenvalues analysis are applied in a full factorial
approach. The results show that introducing front assembly compliance
generates a wobble mode with little effect on self-stability. The forward
displacement of the centre of mass of the rear frame and the increment in trail
lead to large increments in the self-stability, whereas increments in front wheel
radius and wheelbase reduce stability
Waste paper as carbohydrate source for biofuel production: An experimental investigation
No full textRecovering a leading coefficient and a memory kernel in first-order integro-differential operator equations
No full textAbstractWe are concerned with the identification of the scalar functions a and k in the convolution first-order integro-differential equation u′(t)−a(t)Au(t)−k∗Bu(t)=f(t), 0⩽t⩽T, k∗v(t)=∫0tk(t−s)v(s)ds, in a Banach space X, where A and B are linear closed operators in X, A being the generator of an analytic semigroup of linear bounded operators. Taking advantage of two pieces of additional information, we can recover, under suitable assumptions and locally in time, both the unknown functions a and k. The results so obtained are applied to an n-dimensional integro-differential identification problem in a bounded domain in Rn
Fractional Powers and Interpolation Theory for Multivalued Linear Operators and Applications to Degenerate Differential Equations
No full textdepartmental bulletin pape
On the Behaviour of Singular Semigroups in Intermediate and Interpolation Spaces and Its Applications to Maximal Regularity for Degenerate Integro-Differential Evolution Equations
No full textFor those semigroups, which may have power type singularities and whose generators are abstract multivalued linear operators, we characterize the behaviour with respect to a certain set of intermediate and interpolation spaces. The obtained results are then applied to provide maximal time regularity for the solutions to a wide class of degenerate integro- and non-integro-differential evolution equations in Banach spaces
Fondamenti di patologia vegetale
No full textSvariate malattie di natura biotica e abiotica compromettono gravemente la produttività delle colture agrarie e forestali e provocano danni spesso irreversibili all’ambiente ed al paesaggio. La trattazione degli aspetti scientifici e tecnici fondamentali di tali malattie, rivista e puntualmente aggiornata, è riproposta con arricchita veste tipografica in questa seconda edizione dei “Fondamenti di Patologia vegetale” destinata soprattutto agli studenti dei corsi di laurea e di laurea magistrale in Scienze e Tecnologie Agrarie, Scienze Forestali e Ambientali, Viticoltura ed Enologia, Biotecnologie Agro-Alimentari, Scienze e Tecnologie Alimentari e ai tecnici e professionisti chiamati ad affrontare problemi fitopatologici sul territorio
[Poesia] Três poemas de Alberto Secama
No full textThree poems by Alberto Secama. About the author: Alberto Secama is an Angolan poet who has poems published on many websites and on facebook:https://www.facebook.com/Xungurra/abouthttp://www.pordentrodaafrica.com/cultura/africa-em-verso-rio-kwanza-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/africa-em-verso-zong-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/coluna-africa-em-verso-o-sol-la-fora-por-alberto-secamaTres poemas de Alberto Secama. Sobre el autor: Alberto Secama es un poeta angoleño que tiene poemas publicados en varios sitios y en el facebook:https://www.facebook.com/Xungurra/abouthttp://www.pordentrodaafrica.com/cultura/africa-em-verso-rio-kwanza-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/africa-em-verso-zong-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/coluna-africa-em-verso-o-sol-la-fora-por-alberto-secamaTrês poemas de Alberto Secama. Sobre o autor: Alberto Secama é um poeta angolano que possui poemas publicados em vários sites e no facebook:https://www.facebook.com/Xungurra/abouthttp://www.pordentrodaafrica.com/cultura/africa-em-verso-rio-kwanza-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/africa-em-verso-zong-por-alberto-secamahttp://www.pordentrodaafrica.com/cultura/coluna-africa-em-verso-o-sol-la-fora-por-alberto-secam
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