On the analytical derivation of the Pareto-optimal set with applications to structural design

The Fritz John conditions for Pareto-optimality have been set in matrix form and used for introducing a procedure for the analytical derivation of the Pareto-optimal set in the design variables domain. Subsequently, the derivation of the Pareto-optimal set in the objective functions domain can be obtained, if possible, by a proper analytical derivation. Both the objective and constraint functions are assumed to be available in analytical form and twice differentiable and convex (or pseudo-convex). The proposed procedure to find the Pareto-optimal set is relatively simple. The computation of the determinant of a matrix is required. A symbolic manipulator can be exploited. If there are two design variables and two objective functions, the Pareto-optimal set can be easily computed by applying a simple formula derived in the paper. If the number of design variables equals the number of objective functions, the Pareto-optimal set in the design variables domain can be found by computing the product of the constraint functions times the determinant of the Jacobian of the objective functions. A number of case studies have been proposed to test the effectiveness of the proposed procedure. The optimal structural design of, respectively, a pair of compressed spheres, a cantilever with rectangular cross section have been faced and solved. Additionally the test problem proposed by Fonseca and Fleming has been addressed and solved analytically. Optimization problems with low dimensionality (2 or 3 design variables and 2 objective functions, 2 or more constraints) have been easily solved. The proposed procedure can be useful in the actual engineering practice at the earliest design stage. In this case the designer can be made aware on the proper design variables setting to obtain the desired tradeoff among conflicting objective functions.     

A method for measuring the inertia properties of rigid bodies

A method for the measurement of the inertia properties of rigid bodies is presented. Given a rigid body and its mass, the method allows to measure (identify) the centre of gravity location and the inertia tensor during a single test. The proposed technique is based on the analysis of the free motion of a multi-cable pendulum to which the body under consideration is connected. The motion of the pendulum and the forces acting on the system are recorded and the inertia properties are identified by means of a proper mathematical procedure based on a least square estimation. After the body is positioned on the test rig, the full identification procedure takes less than 10 min. The natural frequencies of the pendulum and the accelerations involved are quite low, making this method suitable for many practical applications. In this paper, the proposed method is described and two test rigs are presented: the first is developed for bodies up to 3500 kg and the second for bodies up to 400 kg. A validation of the measurement method is performed with satisfactory results. The test rig holds a third part quality certificate according to an ISO 9001 standard and could be scaled up to measure the inertia properties of huge bodies, such as trucks, airplanes or even ships.     

An application of multi-objective stochastic optimisation to structural design

An application to structural design of an innovative method for optimising stochastic systems is introduced in the paper. The proposed method allows one to carry out both the multi-objective optimisation of a structural element and to improve the robustness of the design. The innovative method is rather general. To show its effectiveness, an ideal cantilever has been designed in order to minimise both mass and deflection. The cantilever is shaped as a beam and is subject to random loads acting at its free end. The beam geometrical dimensions and material properties vary stochastically due to manufacturing tolerances. Different beam cross sections and two different materials (aluminium alloy and steel) have been considered. From the optimisation, it turned out that the optimal solutions are the O and the I beam, depending on the required lightness and stiffness. Compared to steel, aluminium alloy beams have provided better (or at least equal) performance.     

Emotional responses to taste and smell stimuli: Self-reports,physiological measures,and a potential role for individual and genetic factors

Taste and olfaction elicit conscious feelings by direct connection with the neural circuits of emotions that affects physiological responses in the body (e.g., heart rate and skin conductance). While sensory attributes are strong determinants of food liking, other factors such as emotional reactions to foods may be better predictors of consumer choices even for products that are equally-liked. Thus, important insights can be gained for understanding the full spectrum of emotional reactions to foods that inform the activities of product developers and marketers, eating psychologist and nutritionists, and policy makers. Today, self-reported questionnaires and physiological measures are the most common tools applied to study variations in emotional perception. The present review discusses these methodological approaches, underlining their different strengths and weaknesses. We also discuss a small, emerging literature suggesting that individual differences and genetic variations in taste and smell perception, like the genetic ability to perceive the bitter compound PROP, may also play a role in emotional reactions to aromas and foods.     

Impact of Silicon Foliar Application on the Growth and Physiological Traits of Carthamus tinctorius L. Exposed to Salt Stress

Silicon - Althought safflower is a tolerant crop against many environmental stresses, but its yield and performance reduce under stress. The aim of this experiment was to investigate the effect of...     

Analysis of an unusual McPherson suspension failure

In this paper the cause of premature failure of the upper strut mount of a McPherson suspension is investigated. The work was prompted by the fact that the failed component has been used for at least four decades by a car manufacturer without reporting any premature failure and therefore an in depth study of the structural behavior of the component was required. Both experimental tests and numerical analyses have been carried out in order to estimate the service life of the component. The fatigue life of the component has been assessed by a defect tolerant analysis. The result of the investigation is that the upper strut mount failure was due to an impulsive load that can not be justified by the static and dynamic loads acting on the component caused by road irregularities and vehicle manoeuvring during usual working conditions.     

Complete response to IFN in a case of typical HBV cirrhosis

A rare case of "wild-type" HBV cirrhosis (CHIL A/HBeAG+/HBV-DNA+) with complete response to IFN treatment after 3 successive series based on different types of IFN is reported. In this patient, HBeAg and HBV-DNA negativization after the second treatment with r-alpha-2b-IFN was observed and after the third treatment with lymphoblastoid-IFN HBcAb,-IgM negativization simultaneously with ALT persistent normalization. Over one year after the interruption of the last treatment, HBV clearance with HBsAg elimination and HBsAb, seroconversion was observed. The effectiveness of IFN was histologically confirmed with decrease of the piecemeal necrosis in the liver and presence of light fibrosis whereas the results of 3 previous histological evaluations showed: 1) CPH (1985); 2) CAH lightly active with initial signs of cirrhotic evolution (1988); 3) CAH with presence of nodular cirrhosis in the liver (1991). In particularly selected cases the possibility of a favourable response to the series of IFN treatment is stresses even in more advanced chronic "wild" HBV forms in which there is not evidence of mutants in the viral population.     

Bending of beams of arbitrary cross sections - optimal design by analytical formulae

The paper deals with the conceptual design of a beam under bending. The common problem of designing a beam in a state of pure bending is discussed in the framework of Pareto-optimality theory. The analytical formulation of the Pareto-optimal set is derived by using a procedure based on the reformulation of the Fritz John Pareto-optimality conditions. The shape of the cross section of the beam is defined by a number of design variables pertaining to the optimization process by means of efficiency factors. Such efficiency factors are able to describe the bending properties of any beam cross section and can be used to derive analytical formulae. Design performance is determined by the combination of cross section shape, material and process. Simple expressions for the Pareto-optimal set of a beam of arbitrary cross section shape under bending are derived. This expression can be used at the very early stage of the design to choose a possible cross section shape and material for the beam among optimal solutions.