Gnecco, Giorgio

Sanguineti, Marcello

English

IMT Institutional Repository

Applied Mathematical Sciences, Vol. 4, 2010, no. 73, 3621 - 3624EditorialGiorgio Gnecco and Marcello SanguinetiDepartment of Communications, Computer and System Sciences (DIST)University of GenoaVia Opera Pia, 13 - 16145 Genova - Italygiorgio.gnecco@dist.unige.it, marcello@dist.unige.itDealing with the increasing complexity of problems arising in modern sci-ence and technology often requires powerful mathematical tools and method-ologies. While developments in computer technology allow the solution ofincrementally larger problems, it appears that conceptual insights will be nec-essary to reach the required scale of complexity. An interdisciplinary approachmay foster these insights.The conference series “Mathematical Problems in Engineering, Aerospace,and Sciences” (ICNPAA) aims at bringing together scholars, leading researchers,and experts from diverse backgrounds and application areas. Special empha-sis is put on promoting interaction between the theoretical and experimentalscientific communities in order to achieve a high-level of exchange in new andemerging areas among engineering, science, and applied mathematics. Theconferences in this series have become an important biennial event, attractingmany scientists, engineers, and researchers from academia, government labo-ratories, and industry.In 1996, 1998 and 2000 the conference was hosted by the Embry-RiddleAeronautical University at Daytona Beach, Florida (USA). ICNPAA 2002 washeld at the Florida Institute of Technology of Melbourne, again in Florida.The three successive meetings took place in Europe: at the West Universityof Timisoara (Romania) in 2004, at the Budapest University of Technologyand Economics (Hungary) in 2006, and at the Faculty of Engineering of theUniversity of Genova (Italy), in 2008. In 2010, the ICNPAA venue was theINPE National Institute for Space Research of Sa˜o Jose´ dos Campos, in Brazil.This special issue is devoted to a selection of papers containing extendedversions of some works presented from June 24 to June 27 at ICNPAA 2008,which hosted about 300 participants from more than 50 countries.The twelve selected papers deal with a broad spectrum of mathematical3622 G. Gnecco and M. Sanguinetiproblems arising in science and engineering. Some works give methodologi-cal contributions, others offer more theoretically-oriented studies, while stilla third group focus directly on applications. Topics addressed include con-trol of hydraulic systems, simulation models for thermal and mechanical stressdistribution, forecast of freeway traffic conditions to stochastic analysis of in-vestments via Monte-Carlo simulation, structural flexibility of modern flightvehicles, adhesion and decohesion phenomena in mechanics, and flight per-formance of solar-powered aircraft. Such a wide variety of topics reflects thebroad spectrum of the conference.We hope that this special issue will contribute to fruitful scientific collabo-ration, stimulate interaction among scientists from a variety of disciplines, andimprove the applicability of mathematical methods to challenging problemsfrom engineering and applied sciences.Finally, we would like to express our thanks to the referees for their carefulwork and to the authors who submitted their research results.The paper by S. Balea, A. Halanay, and I. Ursu deals with electro-hydraulicservomechanisms (EHS). The control of hydraulic systems is a challengingtask, due to the presence of nonlinearities that arise from properties such asfluid compressibility, complex flow properties of hydraulic valves, and frictioncharacteristic. Most existing models developed for the control design of EHSsfor flight control systems neglect the influence of the mounting structure’selasticity on system stability. In this work, the authors investigate the controlsynthesis in a servoelastic framework, defined by the finite mounting structurestiffness of an EHS. They also address stabilization of the switched systemequilibria.S. Balint and L. Tanasie consider the cutting process into slices for ingotsof circular or square cross-sections of certain single crystals produced by meltgrowth techniques. In particular, they address the edge-defined film-fed growth(EFG) technique. For such a technique, they face the problem of choosing thepressure differences across the outer and inner free surfaces, in order to obtaina stable convex static meniscus with a prescribed size. The dependence ofthese pressure differences on the composition is investigated.The Sumudu Transform and some of its applications are the topic of thework by F. B. M. Belgacem. The properties of this recently-developed math-ematical tool are investigated, extended, and exploited to deal with Besselequations. A comparison with the Laplace transform is made and cases inwhich the Sumudu transform may show advantages over the Laplace are dis-cussed.The work by S. Bracco describes two simulation models developed in theMatlab/Simulink environment to evaluate the thermal and mechanical stressdistribution inside the metal part of a steam drum installed into a heat recov-Editorial 3623ery steam generator of a combined cycle power plant. The models are obtainedby applying the Fourier heat conduction equation to calculate temperature val-ues inside both the metal and the insulation of the drum. A finite-differencemethod is exploited to implement the heat transfer mathematical model. Sim-ulation results concerning the validation phase and the analysis of transientoperating conditions of a combined cycle power plant are reported.In the contribution by R. Leticia Corral-Bustamante, D. Saenz, N.I. Arana,J. A. Hurtado, and B. E. Ochoa, the solution of Newton’s equation from clas-sic mechanics is introduced in a relativistic equation obtained from a proposedmetric, which solves the differential equations contained in the Einstein’s con-tracted tensor or Riemann-Christoffel’s tensor. The results obtained using thisapproach are compared with relativistic predictions from other authors.A. Fedi, M. Massabo`, O. Paladino, and R. Cianci address the advection-dispersion equation, used to describe the transport of solutes in saturatedporous media. A closed-form solution is derived for a two-dimensional semi-infinite domain (parallel plate geometry). This is achieved by an approachbased on Fourier series and Laplace transforms, introducing the application ofa Jacobi Theta Function. The domain considered in the paper represents atypical experimental device adopted to study solute transport through porousmedia. To evaluate the influence of the presence of the boundaries on theplume profiles behavior, the solution is compared with a commonly-used onefor infinite domain.F. Maddalena, D. Percivale, and G. Puglisi consider models for adhesionand decohesion phenomena, applied both in traditional problems of mechanicsand in modern technological contexts. A parameter playing a major role inmacroscopic behavior is the relative strength of the glue or detaching layer andthe connected bodies. The authors compare two different approaches that theyrecently proposed to study the debonding problem of an elastic beam gluedto a rigid substrate and subject to a force at one of its end-points. In thefirst model, a Bernoulli-Navier linearly elastic beam with a decohesion energydepending on the measure of the detached zone is considered. In the secondmodel, the behavior of a discrete lattice of massless points connected by shearsprings and by breakable links to a rigid layer is addressed.The paper by G. Sachs, J. Lenz and F. Holzapfel deals with a model of solarairplane that offers the possibility of an unlimited flight endurance. The solar-powered vehicle is equipped with batteries that can store enough energy fornight flight, when no solar radiation is available. The endurance flight methodis regarded as a problem of periodic optimal control, in which a single day-nightcycle has to be optimized. The goal of an unlimited endurance performance istreated as a trajectory optimization problem. The optimization goal addressedin the paper consists in minimizing the required capacity of the batteries and,thus, in providing a contribution to keep the related weight penalty as small3624 G. Gnecco and M. Sanguinetias possible.G. Sachs and M. Mayrhofer investigate gliding flight which involves jet-tisoning - an issue for a space transportation system consisting of a wingedorbital stage and a carrier stage. Jettisoning is applied for various purposes,one of which is to intentionally decrease the mass of the aircraft. The au-thors show that the range performance of aerial vehicles in gliding flight canbe increased by an optimal application of jettisoning, which is considered as acontrol and included in the trajectory optimization. Results are demonstratedfor two vehicles, one of which relates to the high end of the speed spectrum(orbital stage) while the other applies to the low end (sailplane).The departure point of the paper by C. Caligaris, S. Sacone, and S. Siriis the classic second-order Payne-Whitham macroscopic model (PW-Model),used to represent and forecast traffic conditions in a freeway. The authors ad-dress the problem of choosing suitable sampling intervals for the discretizationsrequired to obtain numerical solutions to the partial differential equations, fromwhich the model comes. Boundaries are defined for sampling intervals, suchthat the instability of the numerical scheme is avoided. The analysis is appliedboth to PW-Model and to its extension developed by the authors themselvesin a previous work.The paper by L. Cassettari, P.G. Giribone, M. Mosca, and R. Mosca ismotivated by two problems that arise when applying simulation to stochasticanalysis of investments: lack of knowledge regarding the experimental errorand undervaluation of the mean variance. (Typically, mean variance plays amajor role.) The authors develop a methodology to study investments throughMonte-Carlo simulation. They define the curve of evolution of the Mean-Square Pure Error in such a way as to optimize the number of experimentalruns, and they give scenarios required to achieve a complete vision of the prob-lem under study. The methodology is applied to a realistic case of investmentin a production line for a food product.The work by H. H. Hilton is motivated by the deflection, during flight, oflifting surfaces and fuselages and their skin panels, due the high structuralflexibility of modern flight vehicles. The author focuses on panels and their re-sponses to aerodynamic noise. He investigates in terms of order-of-magnitudeanalysis the nature of loading sources and panel responses to determine theirlinear or nonlinear contributions. Nonlinear results are evaluated and com-pared to linear solutions and some numerical simulations are made.Received: August, 2010

Editorial for the special issue: “Mathematical problems in engineering, aerospace and sciences”

Applied Mathematical Sciences, Vol. 4, 2010, no. 73, 3621 - 3624EditorialGiorgio Gnecco and Marcello SanguinetiDepartment of Communications, Computer and System Sciences (DIST)University of GenoaVia Opera Pia, 13 - 16145 Genova - Italygiorgio.gnecco@dist.unige.it, marcello@dist.unige.itDealing with the increasing complexity of problems arising in modern sci-ence and technology often requires powerful mathematical tools and method-ologies. While developments in computer technology allow the solution ofincrementally larger problems, it appears that conceptual insights will be nec-essary to reach the required scale of complexity. An interdisciplinary approachmay foster these insights.The conference series “Mathematical Problems in Engineering, Aerospace,and Sciences” (ICNPAA) aims at bringing together scholars, leading researchers,and experts from diverse backgrounds and application areas. Special empha-sis is put on promoting interaction between the theoretical and experimentalscientiﬁc communities in order to achieve a high-level of exchange in new andemerging areas among engineering, science, and applied mathematics. Theconferences in this series have become an important biennial event, attractingmany scientists, engineers, and researchers from academia, government labo-ratories, and industry.In 1996, 1998 and 2000 the conference was hosted by the Embry-RiddleAeronautical University at Daytona Beach, Florida (USA). ICNPAA 2002 washeld at the Florida Institute of Technology of Melbourne, again in Florida.The three successive meetings took place in Europe: at the West Universityof Timisoara (Romania) in 2004, at the Budapest University of Technologyand Economics (Hungary) in 2006, and at the Faculty of Engineering of theUniversity of Genova (Italy), in 2008. In 2010, the ICNPAA venue was theINPE National Institute for Space Research of Sa˜o Jose´ dos Campos, in Brazil.This special issue is devoted to a selection of papers containing extendedversions of some works presented from June 24 to June 27 at ICNPAA 2008,which hosted about 300 participants from more than 50 countries.The twelve selected papers deal with a broad spectrum of mathematical3622 G. Gnecco and M. Sanguinetiproblems arising in science and engineering. Some works give methodologi-cal contributions, others oﬀer more theoretically-oriented studies, while stilla third group focus directly on applications. Topics addressed include con-trol of hydraulic systems, simulation models for thermal and mechanical stressdistribution, forecast of freeway traﬃc conditions to stochastic analysis of in-vestments via Monte-Carlo simulation, structural ﬂexibility of modern ﬂightvehicles, adhesion and decohesion phenomena in mechanics, and ﬂight per-formance of solar-powered aircraft. Such a wide variety of topics reﬂects thebroad spectrum of the conference.We hope that this special issue will contribute to fruitful scientiﬁc collabo-ration, stimulate interaction among scientists from a variety of disciplines, andimprove the applicability of mathematical methods to challenging problemsfrom engineering and applied sciences.Finally, we would like to express our thanks to the referees for their carefulwork and to the authors who submitted their research results.The paper by S. Balea, A. Halanay, and I. Ursu deals with electro-hydraulicservomechanisms (EHS). The control of hydraulic systems is a challengingtask, due to the presence of nonlinearities that arise from properties such asﬂuid compressibility, complex ﬂow properties of hydraulic valves, and frictioncharacteristic. Most existing models developed for the control design of EHSsfor ﬂight control systems neglect the inﬂuence of the mounting structure’selasticity on system stability. In this work, the authors investigate the controlsynthesis in a servoelastic framework, deﬁned by the ﬁnite mounting structurestiﬀness of an EHS. They also address stabilization of the switched systemequilibria.S. Balint and L. Tanasie consider the cutting process into slices for ingotsof circular or square cross-sections of certain single crystals produced by meltgrowth techniques. In particular, they address the edge-deﬁned ﬁlm-fed growth(EFG) technique. For such a technique, they face the problem of choosing thepressure diﬀerences across the outer and inner free surfaces, in order to obtaina stable convex static meniscus with a prescribed size. The dependence ofthese pressure diﬀerences on the composition is investigated.The Sumudu Transform and some of its applications are the topic of thework by F. B. M. Belgacem. The properties of this recently-developed math-ematical tool are investigated, extended, and exploited to deal with Besselequations. A comparison with the Laplace transform is made and cases inwhich the Sumudu transform may show advantages over the Laplace are dis-cussed.The work by S. Bracco describes two simulation models developed in theMatlab/Simulink environment to evaluate the thermal and mechanical stressdistribution inside the metal part of a steam drum installed into a heat recov-Editorial 3623ery steam generator of a combined cycle power plant. The models are obtainedby applying the Fourier heat conduction equation to calculate temperature val-ues inside both the metal and the insulation of the drum. A ﬁnite-diﬀerencemethod is exploited to implement the heat transfer mathematical model. Sim-ulation results concerning the validation phase and the analysis of transientoperating conditions of a combined cycle power plant are reported.In the contribution by R. Leticia Corral-Bustamante, D. Saenz, N.I. Arana,J. A. Hurtado, and B. E. Ochoa, the solution of Newton’s equation from clas-sic mechanics is introduced in a relativistic equation obtained from a proposedmetric, which solves the diﬀerential equations contained in the Einstein’s con-tracted tensor or Riemann-Christoﬀel’s tensor. The results obtained using thisapproach are compared with relativistic predictions from other authors.A. Fedi, M. Massabo`, O. Paladino, and R. Cianci address the advection-dispersion equation, used to describe the transport of solutes in saturatedporous media. A closed-form solution is derived for a two-dimensional semi-inﬁnite domain (parallel plate geometry). This is achieved by an approachbased on Fourier series and Laplace transforms, introducing the application ofa Jacobi Theta Function. The domain considered in the paper represents atypical experimental device adopted to study solute transport through porousmedia. To evaluate the inﬂuence of the presence of the boundaries on theplume proﬁles behavior, the solution is compared with a commonly-used onefor inﬁnite domain.F. Maddalena, D. Percivale, and G. Puglisi consider models for adhesionand decohesion phenomena, applied both in traditional problems of mechanicsand in modern technological contexts. A parameter playing a major role inmacroscopic behavior is the relative strength of the glue or detaching layer andthe connected bodies. The authors compare two diﬀerent approaches that theyrecently proposed to study the debonding problem of an elastic beam gluedto a rigid substrate and subject to a force at one of its end-points. In theﬁrst model, a Bernoulli-Navier linearly elastic beam with a decohesion energydepending on the measure of the detached zone is considered. In the secondmodel, the behavior of a discrete lattice of massless points connected by shearsprings and by breakable links to a rigid layer is addressed.The paper by G. Sachs, J. Lenz and F. Holzapfel deals with a model of solarairplane that oﬀers the possibility of an unlimited ﬂight endurance. The solar-powered vehicle is equipped with batteries that can store enough energy fornight ﬂight, when no solar radiation is available. The endurance ﬂight methodis regarded as a problem of periodic optimal control, in which a single day-nightcycle has to be optimized. The goal of an unlimited endurance performance istreated as a trajectory optimization problem. The optimization goal addressedin the paper consists in minimizing the required capacity of the batteries and,thus, in providing a contribution to keep the related weight penalty as small3624 G. Gnecco and M. Sanguinetias possible.G. Sachs and M. Mayrhofer investigate gliding ﬂight which involves jet-tisoning - an issue for a space transportation system consisting of a wingedorbital stage and a carrier stage. Jettisoning is applied for various purposes,one of which is to intentionally decrease the mass of the aircraft. The au-thors show that the range performance of aerial vehicles in gliding ﬂight canbe increased by an optimal application of jettisoning, which is considered as acontrol and included in the trajectory optimization. Results are demonstratedfor two vehicles, one of which relates to the high end of the speed spectrum(orbital stage) while the other applies to the low end (sailplane).The departure point of the paper by C. Caligaris, S. Sacone, and S. Siriis the classic second-order Payne-Whitham macroscopic model (PW-Model),used to represent and forecast traﬃc conditions in a freeway. The authors ad-dress the problem of choosing suitable sampling intervals for the discretizationsrequired to obtain numerical solutions to the partial diﬀerential equations, fromwhich the model comes. Boundaries are deﬁned for sampling intervals, suchthat the instability of the numerical scheme is avoided. The analysis is appliedboth to PW-Model and to its extension developed by the authors themselvesin a previous work.The paper by L. Cassettari, P.G. Giribone, M. Mosca, and R. Mosca ismotivated by two problems that arise when applying simulation to stochasticanalysis of investments: lack of knowledge regarding the experimental errorand undervaluation of the mean variance. (Typically, mean variance plays amajor role.) The authors develop a methodology to study investments throughMonte-Carlo simulation. They deﬁne the curve of evolution of the Mean-Square Pure Error in such a way as to optimize the number of experimentalruns, and they give scenarios required to achieve a complete vision of the prob-lem under study. The methodology is applied to a realistic case of investmentin a production line for a food product.The work by H. H. Hilton is motivated by the deﬂection, during ﬂight, oflifting surfaces and fuselages and their skin panels, due the high structuralﬂexibility of modern ﬂight vehicles. The author focuses on panels and their re-sponses to aerodynamic noise. He investigates in terms of order-of-magnitudeanalysis the nature of loading sources and panel responses to determine theirlinear or nonlinear contributions. Nonlinear results are evaluated and com-pared to linear solutions and some numerical simulations are made.Received: August, 2010

Editorial for the special issue: “Mathematical problems in engineering, aerospace and sciences”

Abstract

Similar works

Full text

Available Versions

IMT Institutional Repository

IMT Institutional Repository

Archivio della ricerca della Scuola IMT Alti Studi Lucca