Pneumatikoetako kautxu birziklatuz fabrikaturiko material baten karakterizazioa kolpeen aurrean

348 p.Doktorego Tesi honetan pneumatikoetako kautxua birziklatzeko helburuarekin, aplikazio potentzial modura moto-ziklisten babeserako errepideetako hesietan estaldura moduan eman zaio. Horretarako LLDPEarekin osatutako nahastea egin da proportzio desberdinetan eta material horren karakterizazio mekanikoa aurkezten da. Abiadura altuko konpresiozko saiakuntzak egiten dira, eman nahi zaion erabilera inpaktuen barne dagoela kontuan izanik.Literaturan ondo ezagutzen den eredu osagarri hiper-biskoelastikoa aukeratu da materiala karakterizatzeko, hain zuzen ere Yang-en eredua. Bere zati biskoelastikoko parametroak Particle Swarm Optimization (PSO) algoritmoaren bitartez doitu dira.Abiadurarik altuenean materialaren kurbek ondulazio bereizgarri batzuek (¿ringing¿ moduan ezagutzen direnak) aurkeztu dituztenez datu esperimentalak distortsionatuz, Analisi Modal Esperimentala (EMA) kontsideratu da makina serbo-hidraulikoaren ezaugarri dinamikoak xehetasunez ikasteko asmoz eta hemendik ateratako eredu matematiko baten bidez datu esperimentalen oszilazioak minimizatu ahal izan dira.Azkenik, Yang-en eredua EFen software-an inplementatu ahal izateko metodologia aurkezten da

Pneumatikoetako kautxu birziklatuz fabrikaturiko material baten karakterizazioa kolpeen aurrean

348 p.Doktorego Tesi honetan pneumatikoetako kautxua birziklatzeko helburuarekin, aplikazio potentzial modura moto-ziklisten babeserako errepideetako hesietan estaldura moduan eman zaio. Horretarako LLDPEarekin osatutako nahastea egin da proportzio desberdinetan eta material horren karakterizazio mekanikoa aurkezten da. Abiadura altuko konpresiozko saiakuntzak egiten dira, eman nahi zaion erabilera inpaktuen barne dagoela kontuan izanik.Literaturan ondo ezagutzen den eredu osagarri hiper-biskoelastikoa aukeratu da materiala karakterizatzeko, hain zuzen ere Yang-en eredua. Bere zati biskoelastikoko parametroak Particle Swarm Optimization (PSO) algoritmoaren bitartez doitu dira.Abiadurarik altuenean materialaren kurbek ondulazio bereizgarri batzuek (¿ringing¿ moduan ezagutzen direnak) aurkeztu dituztenez datu esperimentalak distortsionatuz, Analisi Modal Esperimentala (EMA) kontsideratu da makina serbo-hidraulikoaren ezaugarri dinamikoak xehetasunez ikasteko asmoz eta hemendik ateratako eredu matematiko baten bidez datu esperimentalen oszilazioak minimizatu ahal izan dira.Azkenik, Yang-en eredua EFen software-an inplementatu ahal izateko metodologia aurkezten da

Scientific Advances in STEM: From Professor to Students

This book collects the publications of the special Topic Scientific advances in STEM: from Professor to students. The aim is to contribute to the advancement of the Science and Engineering fields and their impact on the industrial sector, which requires a multidisciplinary approach. University generates and transmits knowledge to serve society. Social demands continuously evolve, mainly because of cultural, scientific, and technological development. Researchers must contextualize the subjects they investigate to their application to the local industry and community organizations, frequently using a multidisciplinary point of view, to enhance the progress in a wide variety of fields (aeronautics, automotive, biomedical, electrical and renewable energy, communications, environmental, electronic components, etc.). Most investigations in the fields of science and engineering require the work of multidisciplinary teams, representing a stockpile of research projects in different stages (final year projects, master’s or doctoral studies). In this context, this Topic offers a framework for integrating interdisciplinary research, drawing together experimental and theoretical contributions in a wide variety of fields

Estratégias evolucionárias de optimização de parâmetros reais

Mestrado em Engenharia MecânicaActualmente, existem diversos problemas de engenharia cujas propriedades podem ser expressas através de uma função, denominada função objectivo. Existem diversos métodos que possuem como principal objectivo minimizar a referida função. Os métodos baseados no gradiente são métodos nos quais a direcção e tamanho do passo são calculados a partir do declive da função objectivo. Apesar destes métodos necessitarem de reduzidos tempos de computação, estes podem convergir prematuramente ou ficar estagnados em mínimos locais. Os métodos de optimização baseados na teoria evolucionária são aproximações que possuem como principal desvantagem elevados tempos de computação. No entanto, estes apresentam uma grande flexibilidade na modelação de problemas de engenharia. Neste grupo, os algoritmos mais conhecidos e aplicados em problemas de optimização são os Algoritmos Evolucionários (EA’s), Algoritmos Genéticos (GA’s) e Evolução Diferencial (DE). Existem ainda algoritmos baseados em processos naturais tais como o algoritmo de Optimização por Bandos de Partículas (PSO), que reproduz o comportamento de bandos de animais. Neste trabalho é desenvolvido um algoritmo de optimização de procura directa baseado em métodos diferenciais, evolucionários e no comportamento de animais. O algoritmo desenvolvido é aplicado a problemas de engenharia inversa. Numa primeira fase, o algoritmo desenvolvido é validado e comparado com algoritmos existentes recorrendo a um conjunto de funções compostas especialmente criadas para este fim. Numa segunda fase, o algoritmo desenvolvido é aplicado a problemas de Engenharia Mecânica e Mecânica Computacional. Nesta secção, os problemas das três barras e da cúpula de 120 barras são analisados recorrendo ao Método dos Elementos Finitos (MEF). Seguidamente, os problemas de compressão de um provete cilíndrico e da placa com furo central são analisados. Nestes problemas a função a minimizar é dada por um programa do MEF comercial. Finalmente, o algoritmo é aplicado a um problema de identificação de parâmetros de um modelo constitutivo. O algoritmo desenvolvido apresenta bons resultados e uma boa taxa de convergência. ABSTRACT: Nowadays, there are many inverse engineering problems whose properties can be expressed by a function, called objective function. There are several methods whose main goal is to minimize the value of that function. The gradient-based methods are optimization methods in which the step direction and length are calculated in terms of the objective function's slope. Although these methods require little computation time, they may converge prematurely or get trapped in a local minima. The optimization methods based on the evolutionary theory are approaches that need, as a main disadvantage, high computation times. However, they have a great flexibility in modeling engineering problems. In this class of methods, the ones that are best known and more often applied in optimization problem are the Evolutionary Algorithms (EA's), Genetic Algorithms (GA's) and Differential Evolution (DE). There are also nature-inspired algorithms such as the Particle Swarm Optimization method (PSO) that mimics the behavior of animal swarms. In this work a direct search optimization algorithm based on differential and evolutionary methods as well as in the behavior of animals is developed. This algorithm is applied to inverse engineering problems. In a first stage, the developed algorithm is validated and compared with existing optimization algorithms using a set of composite functions specially design for that purpose. In a second phase, the algorithm is applied to Engineering and Computational Mechanics problems. In this section, the three-truss bar problem and the 120-bar dome truss problem that are solved using the Finite Element Method (FEM) are analyzed. Subsequently, the compression of a cylindrical billet and the plate with a central cut-out problems are analyzed. In these problems, the function to minimize is given by a commercial FEM code. Finally, the algorithm is applied to a constitutive model parameter identification problem. The develop algorithm obtains good results and a good convergence rate

Mass Transfer in Multiphase Systems and its Applications

This book covers a number of developing topics in mass transfer processes in multiphase systems for a variety of applications. The book effectively blends theoretical, numerical, modeling and experimental aspects of mass transfer in multiphase systems that are usually encountered in many research areas such as chemical, reactor, environmental and petroleum engineering. From biological and chemical reactors to paper and wood industry and all the way to thin film, the 31 chapters of this book serve as an important reference for any researcher or engineer working in the field of mass transfer and related topics

Agricultural Structures and Mechanization

In our globalized world, the need to produce quality and safe food has increased exponentially in recent decades to meet the growing demands of the world population. This expectation is being met by acting at multiple levels, but mainly through the introduction of new technologies in the agricultural and agri-food sectors. In this context, agricultural, livestock, agro-industrial buildings, and agrarian infrastructure are being built on the basis of a sophisticated design that integrates environmental, landscape, and occupational safety, new construction materials, new facilities, and mechanization with state-of-the-art automatic systems, using calculation models and computer programs. It is necessary to promote research and dissemination of results in the field of mechanization and agricultural structures, specifically with regard to farm building and rural landscape, land and water use and environment, power and machinery, information systems and precision farming, processing and post-harvest technology and logistics, energy and non-food production technology, systems engineering and management, and fruit and vegetable cultivation systems. This Special Issue focuses on the role that mechanization and agricultural structures play in the production of high-quality food and continuously over time. For this reason, it publishes highly interdisciplinary quality studies from disparate research fields including agriculture, engineering design, calculation and modeling, landscaping, environmentalism, and even ergonomics and occupational risk prevention

5.Uluslararası Öğrenciler Fen Bilimleri Kongresi Tam Metin Kitabı

Çevrimiçi (IX, 431 Sayfa; 26 cm.)

Application of Wood Composites

This Special Issue "Application of Wood Composites" addresses various aspects of these important wood materials’ use. Topics include the mechanical processing of wood composites, including their cutting, milling, or sanding, incorporating current analysis of wood dust or grain size measurements and the composition of particles; scientific views on the influence of various adhesives in the creation process of wood composites and the analysis of their behavior in contact with various wood elements under different conditions; the analysis of input raw materials forming wood composites, including various wood species, but also non-wood lignocellulosic raw materials; and, last but not least, the analysis of bark, which in recent years has become an important and promising raw material involved in the construction of wood composites. The study of the development of the sliding table saw also suitably complements this Special Issue

Chapter 34 - Biocompatibility of nanocellulose: Emerging biomedical applications

Nanocellulose already proved to be a highly relevant material for biomedical applications, ensued by its outstanding mechanical properties and, more importantly, its biocompatibility. Nevertheless, despite their previous intensive research, a notable number of emerging applications are still being developed. Interestingly, this drive is not solely based on the nanocellulose features, but also heavily dependent on sustainability. The three core nanocelluloses encompass cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial nanocellulose (BNC). All these different types of nanocellulose display highly interesting biomedical properties per se, after modification and when used in composite formulations. Novel applications that use nanocellulose includewell-known areas, namely, wound dressings, implants, indwelling medical devices, scaffolds, and novel printed scaffolds. Their cytotoxicity and biocompatibility using recent methodologies are thoroughly analyzed to reinforce their near future applicability. By analyzing the pristine core nanocellulose, none display cytotoxicity. However, CNF has the highest potential to fail long-term biocompatibility since it tends to trigger inflammation. On the other hand, neverdried BNC displays a remarkable biocompatibility. Despite this, all nanocelluloses clearly represent a flag bearer of future superior biomaterials, being elite materials in the urgent replacement of our petrochemical dependence