Rotors on Active Magnetic Bearings: Modeling and Control Techniques

In the last decades the deeper and more detailed understanding of rotating machinery dynamic behavior facilitated the study and the design of several devices aiming at friction reduction, vibration damping and control, rotational speed increase and mechanical design optimization. Among these devices a promising technology is represented by active magnetic actuators which found a great spread in rotordynamics and in high precision applications due to (a) the absence of all fatigue and tribology issues motivated by the absence of contact, (b) the small sensitivity to the operating conditions, (c) the wide possibility of tuning even during operation, (d) the predictability of the behavior. This technology can be classified as a typical mechatronic product due to its nature which involves mechanical, electrical and control aspects, merging them in a single system. The attractive potential of active magnetic suspensions motivated a considerable research effort for the past decade focused mostly on electrical actuation subsystem and control strategies. Examples of application areas are: (a) Turbomachinery, (b) Vibration isolation, (c) Machine tools and electric drives, (d) Energy storing flywheels, (e) Instruments in space and physics, (f) Non-contacting suspensions for micro-techniques, (g) Identification and test equipment in rotordynamics. This chapter illustrates the design, the modeling, the experimental tests and validation of all the subsystems of a rotors on a five-axes active magnetic suspension. The mechanical, electrical, electronic and control strategies aspects are explained with a mechatronic approach evaluating all the interactions between them. The main goals of the manuscript are: • Illustrate the design and the modeling phases of a five-axes active magnetic suspension; • Discuss the design steps and the practical implementation of a standard suspension control strategy; • Introduce an off-line technique of electrical centering of the actuators; • Illustrate the design steps and the practical implementation of an online rotor selfcentering control technique. The experimental test rig is a shaft (Weight: 5.3 kg. Length: 0.5 m) supported by two radial and one axial cylindrical active magnetic bearings and powered by an asynchronous high frequency electric motor. The chapter starts on an overview of the most common technologies used to support rotors with a deep analysis of their advantages and drawbacks with respect to active magnetic bearings. Furthermore a discussion on magnetic suspensions state of the art is carried out highlighting the research efforts directions and the goals reached in the last years. In the central sections, a detailed description of each subsystem is performed along with the modeling steps. In particular the rotor is modeled with a FE code while the actuators are considered in a linearized model. The last sections of the chapter are focused on the control strategies design and the experimental tests. An off-line technique of actuators electrical centering is explained and its advantages are described in the control design context. This strategy can be summarized as follows. Knowing that: a) each actuation axis is composed by two electromagnets; b) each electromagnet needs a current closed-loop control; c) the bandwidth of this control is depending on the mechanical airgap, then the technique allows to obtain the same value of the closed-loop bandwidth of the current control of both the electromagnets of the same actuation axis. This approach improves performance and gives more steadiness to the control behavior. The decentralized approach of the control strategy allowing the full suspensions on five axes is illustrated from the design steps to the practical implementation on the control unit. Furthermore a selfcentering technique is described and implemented on the experimental test rig: this technique uses a mobile notch filter synchronous with the rotational speed and allows the rotor to spin around its mass center. The actuators are not forced to counteract the unbalance excitation avoiding saturations. Finally, the experimental tests are carried out on the rotor to validate the suspension control, the off-line electrical centering and the selfcentering technique. The numerical and experimental results are superimposed and compared to prove the effectiveness of the modeling approach

Efecto del tratamiento con omega 3 sobre m?sculo esquel?tico de animales distr?ficos adultos

69 p. Recurso Electr?nicoLa distrofia muscular de Duchenne (DMD) es una enfermedad muscular ligada al cromosoma X recesiva caracterizada por la degeneraci?n progresiva de los m?sculos. El rat?n mdx es el modelo experimental para la DMD, con los m?sculos card?acos y esquel?ticos siendo severamente afectados en etapas posteriores de la enfermedad. Los corticoides pueden retrasar la progresi?n de la enfermedad, pero muestra efectos secundarios graves. Por lo tanto, la b?squeda de nuevos f?rmacos es un aspecto importante de la investigaci?n en esta ?rea. Hemos demostrado anteriormente que la terapia con ?cidos grasos (omega-3) mejora la distrofia en animales mdx en la etapa temprana de la enfermedad. En la presente investigaci?n, se analizaron los efectos de los ?cidos grasos (omega-3) sobre la fibrosis y los marcadores moleculares de la progresi?n de la distrofia muscular del cu?driceps en ratones mdx en la etapa posterior (13 meses) de la enfermedad. Los ratones mdx (8 meses de edad) recibieron aceite de omega-3 (aceite de pescado disponible en el mercado; FDC vitaminas, omega-3), durante 5 meses, ratones (C57BL / 10) y ratones mdx control los cuales recibieron aceite mineral durante el mismo per?odo, los cuales ser?n evaluados mediante an?lisis Morfom?tricos ( ?rea de fibrosis e inflamaci?n) y de Western blot pro-inflamatorias (factor de necrosis tumoral, TNF-alfa ,; metaloproteinasa 9, MMP-9, MMP inhibidores tisulares, TIMP1, NFK-B), pro-fibr?tico (factor de crecimiento del tumor, TGF-beta) y los marcadores pro-regenerativos (MyoD). El tratamiento con Omega-3 ha mejorado la progresi?n de la distrofia en los m?sculos cu?driceps, la cual es demostrada por una disminuci?n significativa en la inflamaci?n, degeneraci?n muscular y fibrosis. Si bien se debe tener cuidado al convertir las dosis del f?rmaco de ratones a humanos, el presente estudio sugiere el uso de ?cidos grasos omega-3 en los ensayos cl?nicos de DMD. Palabras clave: Cu?driceps, distrofia Muscular, DMD, mdx, omega-3.Duchenne muscular dystrophy (DMD) is a recessive X-linked muscle disease characterized by progressive degeneration of the muscles. The mdx mouse is the experimental model for DMD, with the cardiac and skeletal muscles being severely affected at later stages of the disease. Corticoids can delay the progression of the disease but show severe side effects. Thus, the search for new drugs is an important aspect of the research in this area. We previously demonstrated in the mdx that omega-3 therapy ameliorated dystrophy, at earlier stages of the disease. In the present investigation, we analyzed the effects of omega-3 on fibrosis and on molecular markers of dystrophy progression in the mdx quadriceps muscle, at later stages (13 months) of the disease. Mdx mice (8 months old) received omega-3 oil (commercially available fish oil; FDC Vitamins; Omega-3), for 5 months. Normal (C57BL/10) and untreated-mdx mice received mineral oil for the same period. Morphometric (fibrosis and inflammatory areas) and western blot of pro-infammatory (tumor necrosis factor, TNF-alpha,; metalloproteinase 9, MMP-9, MMP tissue inhibitors, TIMP1, NFK-b), pro-fibrotic (tumor growth factor, TGF-beta) and pro-regenerative (MyoD) markers were performed. Omega-3 treatment ameliorated dystrophy progression in the quadriceps muscle, as demonstrated by a significant decrease in inflammation, muscle degeneration and fibrosis. While care must be taken when converting drug doses from mice to human, the present study further suggests the use of omega-3 in DMD clinical trials. Keywords: Quadriceps, muscular dystrophy, DMD, mdx, omega-

Thermal analysis as a microstructure prediction tool for A356 aluminium parts solidified under various cooling conditions

Thermal analysis technique has been used for a long time, in both ferrous and nonferrous industries for evaluating the metallurgical quality of the liquid metal before casting. However, obtaining a proper microstructure in a standard cup does not ensure that the microstructure is correct in real parts which may solidify at very different cooling rates. For this study, alloy A356 with different metal quality in terms of modification and grain refinement was tested. Different cooling rates were obtained by using cylindrical test samples with various diameters cast in sand and metallic moulds. The correlation between microstructure features such as grain size, modification rate and secondary dendrite arm spacing (SDAS) measured in the standard thermal analysis cup with those obtained in the cylindrical test parts has been investigated. Thus, knowing the thermal modulus and the mould type it is possible to establish the required grain size and modification rate in the standard cup in order to get a desired structure in a real part. Corrective actions can then be taken in order to improve the metallurgical quality before casting the part

Programas de promoción del empleo asalariado en la provincia de Buenos Aires

El presente documento de trabajo consiste en la presentación de los planes y programas de empleo ejecutados desde el Gobierno de la provincia de Buenos Aires, en el período comprendido entre los años 2000 a 2012. En este primer abordaje del tema, se seleccionó aquellos que promovieran la empleabilidad y la inserción laboral, a través de transferencias monetarias. Un segundo grupo que no está comprendido en la investigación, se compone, en cambio, de estrategias dirigidas al fomento del auto empleo: programas de financiamiento, capacitación y asistencia a emprendimientos y proyectos productivos de la economía social. Esta división se fundamenta en que el primer grupo de herramientas de la política pública tiene como objetivo que los beneficiarios ingresen al mercado de trabajo como obreros o empleados asalariados, mientras los destinatarios del segundo grupo se agregarían a la categoría ocupacional de microemprendedores, miembros de cooperativas de trabajo, de empresas recuperadas, o trabajadores por cuenta propia. La investigación forma parte de las actividades del Departamento de Economía y Administración de la Universidad Nacional de Moreno y se desarrolló en el marco del Proyecto de Investigación Científica y Tecnológica (PICT 2383/06) sobre "Modos de desarrollo y políticas activas de empleo en Argentina (2002-2008)" dirigido por el Dr. Julio César Neffa, con sede en el Centro de Estudios e Investigaciones Laborales del CONICET y contó con el apoyo institucional brindado por el Ministerio de Trabajo de la provincia de Buenos Aires. En el documento se describen 7 instrumentos: Programa Barrios Bonaerenses, Caminos de la Producción, Programas Bonus y Segunda Oportunidad, Plan de Promoción, Preservación y Regularización del Empleo (Pre.BA), Servicio de Colocación Laboral Selectiva (SeCLaS), Programa "Ellas Trabajando" y Programa Oportunidades. En cada caso se ha seguido un mismo esquema de análisis: objetivos, marco normativo, población a la que se dirige, beneficios que otorga, condiciones para el acceso, forma de implementación y gestión, origen del financiamiento, datos cuantitativos y reflexiones finales, incluyendo algunos aspectos de una posible evaluación. Queda pendiente un análisis transversal de estas experiencias, pues este documento de trabajo es el primer producto de una investigación académica mayor, y es un recurso sustancial del trabajo de campo de la Tesis de Maestría en Ciencias Sociales del Trabajo (UBA) de su autora.Fil: Suarez Maestre, Andrea Verónica. Universidad Nacional de Moreno; ArgentinaFil: Neffa, Julio Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; Argentin

Effects of environmental enrichment upon ethanol-induced conditioned place preference and pre-frontal BDNF levels in adolescent and adult mice

Environmental enrichment (EE) provides a non-pharmacological tool to alter drug-induced reward, yet its effects on ethanol-induced reward remain controversial. We analyzed adolescent vs. adult (mice) differences in the influence of EE on ethanol-induced conditioned place preference (CPP). The effects of these treatments on brain-derived neurotrophic factor (BDNF) levels in the prefrontal cortex were examined in a separate group of animals. Ethanol-induced CPP was found in adults, and it was similar in EE and in animals reared under standard housing conditions (SC). Adolescents kept under EE, but not those in SC, exhibited CPP. Among SC, but not among EE, adolescents, BDNF levels were significantly lower in those treated with ethanol than in those given vehicle. These results indicate that, compared to adults, adolescent exhibited reduced sensitivity to ethanol's rewarding effects, yet the youth but not the adults exhibited sensitivity to the promoting effect of EE upon CPP by ethanol. Ethanol significantly reduced BDNF levels in adolescents reared under standard housing conditions, but not in adult mice nor in adolescents given EE housing conditions. The present results add to the plethora of adolescent-specific responses to ethanol or to environmental stimuli that may put the youth at risk for escalation of ethanol intake.Fil: Pautassi, Ricardo Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Suarez, Andrea Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Hoffmann, Lucas Barbosa. Universidade de Sao Paulo; BrasilFil: Rueda, André Veloso. Universidade de Sao Paulo; BrasilFil: Rae, Mariana. Universidade de Sao Paulo; BrasilFil: Marianno, Priscila. Universidade de Sao Paulo; BrasilFil: Camarini, Rosana. Universidade de Sao Paulo; Brasi

The use of Biochar to reduce the carbon footprint of cement-based materials

Abstract The organic waste management is a most current topic, because its processing and degradation it is responsible for emissions of methane and other greenhouse gases, leading to serious environmental problems. Limited oxygen thermochemical processes, such as pyrolysis or gasification, have demonstrated the energy recovery potential of the treated biomass and its environmental benefits. However, the solid part of the process -Biochar- it is considered as a waste, as only its coarse ash can be used as soil improvers. Nevertheless, several researchers have explored its potential application as green filler in order to reduce the carbon footprint both of cement production and cement-based construction materials. In this work, Biochar microparticles were used both as a filler inside the cement paste and mortar composites and as a substitute for the cement powder inside the mixes. Based on previous work, this investigation has a twofold objective: to understand the full influence of the use of an optimized percentage of Biochar (2% with respect to the weight of the cement) either as a filler in the mixture or as a substitute for cement, while guaranteeing an improvement in the strength without losing ductility. The results showed that 2 wt% of Biochar's particles are sufficient to increase the strength and toughness of the cement and mortar composites and, in place of the cement in the mixture, can maintain the mechanical properties equal to those of the reference samples

Proteccion a la Salud en Chile, derecho real o aparente?

72 p.La salud es un tema de interés general presente en cada etapa de la vida de las personas, por esto, no solo la medicina se ha ocupado de ella, sino también el derecho, por medio de la creación de distintas Leyes tanto a nivel nacional como internacional, que permitan su protección. La salud es un derecho que requiere para subsistir, un sistema sanitario que garantice a todos por igual un oportuno y completo acceso a la salud. El Estado es el responsable de garantizar este derecho evitando su vulneración, estableciendo mecanismos de acción, en caso de existir una violación a este derecho fundamental. Nuestra Constitución, considera el Derecho a la Salud como un derecho fundamental, estableciéndolo así en el artículo 19 Nº 9. Se intentará definir la realidad de la salud en nuestro país y a nivel internacional, intentando plasmar las dificultades que presenta el Recurso de Protección en salud