Estudio experimental del desgaste del flanco y de la rugosidad superficial en el torneado en seco de alta velocidad del acero AISI 316L

La mejora continua de los procesos de fabricación es fundamental para alcanzar niveles óptimos de productividad, calidad y coste en la producción de componentes y productos. Para ello es necesario disponer de modelos que relacionen de forma precisa las variables que intervienen en el proceso de corte. Esta investigación tiene como objetivo determinar la influencia de la velocidad de corte y el avance en el desgaste del flanco de los insertos de carburos recubiertos GC1115 y GC2015 y en la rugosidad superficial de la pieza mecanizada de la pieza en el torneado de alta velocidad en seco del acero AISI 316L. Se utilizaron entre otros los métodos de observación científica, experimental, medición, inteligencia artificial y estadísticos. El inserto GC1115 consigue el mejor resultado de acuerdo al gráfico de medias y de las ecuaciones de regresión múltiple de desgaste del flanco para v= 350 m/min, mientras que para las restantes velocidades el inserto GC2015 consigue el mejor desempeño. El mejor comportamiento en cuanto a la rugosidad superficial de la pieza mecanizada se obtuvo con el inserto GC1115 en las velocidades de 350 m/min y 400 m/min, en la velocidad de 450 m/min el mejor resultado correspondió al inserto GC2015. Se analizaron dos criterios nuevos, el coeficiente de vida útil de la herramienta de corte en relación al volumen de metal cortado y el coeficiente de rugosidad superficial de la pieza mecanizada en relación al volumen de metal cortado. Fueron determinados los modelos de regresión múltiple que permitieron calcular el tiempo de mecanizado de los insertos sin que alcanzaran el límite del criterio de desgaste del flanco. Los modelos desarrollados fueron evaluados por sus capacidades de predicción con los valores medidos experimentalmente. ABSTRACT The continuous improvement of manufacturing processes is critical to achieving optimal levels of productivity, quality and cost in the production of components and products. This is necessary to have models that accurately relate the variables involved in the cutting process. This research aims to determine the influence of the cutting speed and feed on the flank wear of carbide inserts coated by GC1115 and GC2015 and the surface roughness of the workpiece for turning dry high speed steel AISI 316L. Among various scientific methods this study were used of observation, experiment, measurement, statistical and artificial intelligence. The GC1115 insert gets the best result according to the graph of means and multiple regression equations of flank wear for v = 350 m / min, while for the other speeds the GC2015 insert gets the best performance. Two approaches are discussed, the life ratio of the cutting tool relative to the cut volume and surface roughness coefficient in relation to the cut volume. Multiple regression models were determined to calculate the machining time of the inserts without reaching the limit of the criterion flank wear. The developed models were evaluated for their predictive capabilities with the experimentally measured values.

MODELOS DE GOVERNANÇA DE TECNOLOGIA DA INFORMAÇÃO ADOTADOS NO BRASIL - UM ESTUDO DE CASOS MÚLTIPLOS

O tema Governança de Tecnologia da Informação (GTI) tornou-se mais premente no ambiente empresarial brasileiro, principalmente após as repercussões mundiais ocorridas com a queda da bolsa de valores americana Nasdaq, com a nova configuração mundial após os ataques aos Estados Unidos em 11 de setembro de 2001 e a partir da promulgação da Lei Sarbanes-Oxley em 2002. Esse modelo de gestão tem sido implementado por organizações que buscam não somente obter melhor controle de gestão em Tecnologia da Informação, como para aquelas que têm de atender às conformidades legais exigidas pelos órgãos de controle. Implementá-la é um processo complexo e desafiador em virtude da necessidade de se identificar o melhor modelo de GTI dentre as práticas existentes no mundo empresarial. As empresas precisam fazer uma composição daquelas que melhor se aderem às suas realidades. Este trabalho tem como objetivo analisar os modelos de GTI adotados em organizações no Brasil, avaliar os seus resultados, seus níveis de maturidade, os seus benefícios, suas dificuldades e suas tendências, contribuindo assim para o seu melhor entendimento e para amenizar a carência de estudos nessa área no Brasil. Este estudo, que é de natureza empírica, baseou-se na metodologia de estudo de casos múltiplos realizado em cinco empresas para explorar como este modelo de gestão vem sendo adotado, quais estruturas, metodologias e práticas de mercado têm sido utilizadas para a sua efetividade. Neste contexto, apresentam-se os resultados obtidos, os aspectos que envolvem a implementação dos modelos de GTI nas organizações, as dificuldades encontradas, o que têm condicionado o seu desempenho e suas tendências.

MODELOS DE GOVERNANÇA DE TECNOLOGIA DA INFORMAÇÃO ADOTADOS NO BRASIL - UM ESTUDO DE CASOS MÚLTIPLOS

O tema Governança de Tecnologia da Informação (GTI) tornou-se mais premente no ambiente empresarial brasileiro, principalmente após as repercussões mundiais ocorridas com a queda da bolsa de valores americana Nasdaq, com a nova configuração mundial após os ataques aos Estados Unidos em 11 de setembro de 2001 e a partir da promulgação da Lei Sarbanes-Oxley em 2002. Esse modelo de gestão tem sido implementado por organizações que buscam não somente obter melhor controle de gestão em Tecnologia da Informação, como para aquelas que têm de atender às conformidades legais exigidas pelos órgãos de controle. Implementá-la é um processo complexo e desafiador em virtude da necessidade de se identificar o melhor modelo de GTI dentre as práticas existentes no mundo empresarial. As empresas precisam fazer uma composição daquelas que melhor se aderem às suas realidades. Este trabalho tem como objetivo analisar os modelos de GTI adotados em organizações no Brasil, avaliar os seus resultados, seus níveis de maturidade, os seus benefícios, suas dificuldades e suas tendências, contribuindo assim para o seu melhor entendimento e para amenizar a carência de estudos nessa área no Brasil. Este estudo, que é de natureza empírica, baseou-se na metodologia de estudo de casos múltiplos realizado em cinco empresas para explorar como este modelo de gestão vem sendo adotado, quais estruturas, metodologias e práticas de mercado têm sido utilizadas para a sua efetividade. Neste contexto, apresentam-se os resultados obtidos, os aspectos que envolvem a implementação dos modelos de GTI nas organizações, as dificuldades encontradas, o que têm condicionado o seu desempenho e suas tendências.

Intermolecular and Intramolecular Charge Transfer in Functional Molecular Materials

This thesis is devoted to the investigation of inter and intramolecular charge transfer (CT) in molecular functional materials and specifically organic dyes and CT crystals. An integrated approach encompassing quantum-chemical calculations, semiempirical tools, theoretical models and spectroscopic measurements is applied to understand structure-property relationships governing the low-energy physics of these materials. Four main topics were addressed: 1) Spectral properties of organic dyes. Charge-transfer dyes are constituted by electron donor (D) and electron acceptor (A) units linked through bridge(s) to form molecules with different symmetry and dimensionality. Their low-energy physics is governed by the charge resonance between D and A groups and is effectively described by a family of parametric Hamiltonians known as essential-state models. These models account for few electronic states, corresponding to the main resonance structures of the relevant dye, leading to a simple picture that is completed introducing the coupling of the electronic system to molecular vibrations, treated in a non-adiabatic way, and an effective classical coordinate, describing polar solvation. In this work a specific essential-state model was proposed and parametrized for the dye Brilliant Green. The central issue in this work has been the definition of the diabatic states, a not trivial task for a multi-branched chromophore. In a second effort, we have used essential-state models for the description of the early-stage dynamics of excited states after ultrafast excitation. Crucial to this work is the fully non-adiabatic treatment of the coupled electronic and vibrational motion, allowing for a reliable description of the dynamics of systems showing a multistable, broken-symmetry excited state. 2) Mixed-stack CT salts. Mixed-stack (MS) CT crystals are an interesting class of multifunctional molecular materials, where D and A molecules arrange themselves to form stacks, leading to delocalized electrons in one dimension. The interplay between the intermolecular CT, electrostatic interactions, lattice phonons and molecular vibrations leads to intriguing physical properties that include (photoinduced) phase transitions, multistability, antiferromagnetism, ferroelectricity and potential multiferroicity. The standard microscopic model to describe this family of materials is the Modified Hubbard model accounting for electron-phonon coupling (Peierls coupling), electron-molecular vibrations coupling (Holstein coupling) and electrostatic interactions. We adopt and validate a method, based on DFT calculations on dimeric DA structures, to extract relevant model parameters. The approach offers a powerful tool to shed light on the complex physics of MS-CT salts. 3) Charge transfer in organic radical dipolar dyes. In collaboration with the group of Prof. Jaume Veciana (ICMAB- Barcellona), we have studied spectral properties of a special class of CT dyes with D-bridge-A structure where the acceptor group is a stable radical (of the perchlorotriphenylmethyl, PTM, family), leading to an open-shell CT dyes. These materials are of interest since they associate the electronic and optical properties of CT dyes with magnetic properties from the unpaired electron. The first effort was devoted to the parametrization of the relevant essential-state model. Two strategies were adopted, one based on the calculation of the low-energy spectral properties, the other based on the variation of ground state properties with an applied electric field. 4) The spectral properties of organic nanoparticles based on radical species are investigated in collaboration with Dr. I. Ratera (ICMAB- Barcellona). Intriguing spectroscopic behavior was observed pointing to the presence of excimer states. In an attempt to rationalize these findings, extensive calculations (TD-DFT and ZINDO) were performed. The results for the isolated dyes are validated against experimental spectra in solution. To address intermolecular interactions we studied dimeric structures in the gas phase, but the preliminary results obtained do not support excimer formation.

Germany and the Eurocrisis: The timing of politics and the politics of timing. ACES Cases No. 2014.3

This paper speculates on the future of the euro. It uses Germany as a prism for the discussion about what might be done next to bolster the Euro. Researching the future—always a challenging task—is made harder when multiple state actors contend for prominence on the basis of shifting coalitions at home, all while interacting at an international level. That said, almost everyone accepts that German choices will play the central role in the path ultimately chosen. This paper thus foregrounds Germany’s role in shaping the way ahead, and it does so through an explicitly political framework focused primarily on the electoral implausibility of an alternative German policy course.

Social Democracy, Globalization and Governance: Why is there no European Left Program in the EU? CES Germany & Europe Working Papers, No. 00.6, April 2000

This paper addresses globalization and governance in the EU by attempting to generate some plausible hypotheses that might explain the policy choices of the 12 out of 15 European democratic left governments. With all of the discussion in recent years of a democratic deficit, and then need to maintain a "social Europe," why have these governments not produced more explicit left-wing policies? It suggests three possible hypotheses to account for this apparently mysterious outcome. Hypothesis #1: They want to but they can't. Hypothesis #2: They don't want to because they aren't really left anymore. Hypothesis #3: They could, but they all are suffering from a fundamental failure of imagination. The paper explores each of these hypotheses in two ways. First it examines the initial years of the Schröder government in Germany apparently, pursuing each of these three hypotheses and different times during this period. Then it looks more systematically and comparatively and each of the three hypotheses by including analysis both of Germany and several other EU member states. The larger goal of this work is to provoke discussion and research on what role left political movements can actually play. Is it even reasonable to expect such a group of nation states to develop innovative forms of cross-national governance? Or are new and/or revised forms of representation and governance beyond traditional nation-state models.

Using Geophysical Tools to Resolve Areas of Seismic Ambiguity

The flanks of an oil-bearing structure were investigated to determine the most likely reservoir geometry in an area where the seismic path forks in preparation for a field equity redetermination. Two alternate hypotheses were evaluated: a “high fork model” where the reservoir top follows the higher of the two paths and a “low fork model” in which the reservoir follows the lower path. I took four approaches to evaluate the hypotheses: 1) Depth conversion by multiple velocity models to evaluate the fidelity of the picked horizon on models that did not contain a fork; 2) hand interpretation around the areas of high uncertainty to eliminate their influence; 3) path choice effects on the plausibility of the environment of deposition; and subsurface geometry modeling with synthetics to compare calculated 1D seismic responses with current data. Investigation established that both fork interpretations cannot follow a continuous seismic reflector but are otherwise equally plausible. Interval modeling revealed several structure scenarios, supporting both high and low fork, which fit the seismic data. To augment the lower fork argument, a scenario with an additional sand interval off-structure is recommended, for simplicity and reasonability.

British and European influences on the "Australian Way" from the 1980s

Commonwealth countries share their British social policy legacy in a variety of ways. Autstralia attempted to adopt the postwar new Fabian welfare state model at the very time when international economic circumstances undermined its Keynesian foundation. With Labor governments in power from 1983 to 1996, Australia diverged significantly from the neo-liberal reform path adopted in the United Kingdom. Australian governments looked increasingly to European social democracies for alternative social policy model In a manner anticipating the Third Way. the tendency was towards mixing neo-liberal economics with social democratic welfare. The Australian Third Way which resulted proved unstable. Current social reformers, the paper proposes, ought to revisit a neglected but characteristically British emphasis on the need for a measure of socialization of investment to underpin redistributive strategies.

Genetic and environmental influences on extreme personality dispositions in adolescent female twins

Background: The objective was to determine whether the pattern of environmental and genetic influences on deviant personality scores differs from that observed for the normative range of personality, comparing results in adolescent and adult female twins. Methods: A sample of 2,796 female adolescent twins ascertained from birth records provided Junior Eysenck Personality Questionnaire data. The average age of the sample was 17.0 years ( S. D. 2.3). Genetic analyses of continuous and extreme personality scores were conducted. Results were compared for 3,178 adult female twins. Results: Genetic analysis of continuous traits in adolescent female twins were similar to findings in adult female twins, with genetic influences accounting for between 37% and 44% of the variance in Extraversion (Ex), Neuroticism (N), and Social Non-Conformity (SNC), with significant evidence of shared environmental influences (19%) found only for SNC in the adult female twins. Analyses of extreme personality characteristics, defined categorically, in the adolescent data and replicated in the adult female data, yielded estimates for high N and high SNC that deviated substantially (p < .05) from those obtained in the continuous trait analyses, and provided suggestive evidence that shared family environment may play a more important role in determining personality deviance than has been previously found when personality is viewed continuously. However, multiple-threshold models that assumed the same genetic and environmental determinants of both normative range variation and extreme scores gave acceptable fits for each personality dimension. Conclusions: The hypothesis of differences in genetic or environmental factors responsible for N and SNC among female twins with scores in the extreme versus normative ranges was partially supported, but not for Ex.

A phase I biological and pharmacologic study of the heparanase inhibitor PI-88 in patients with advanced solid tumors

Purpose: PI-88 is a mixture of highly sulfated oligosaccharides that inhibits heparanase, an extracellular matrix endoglycosidase, and the binding of angiogenic growth factors to heparan sulfate. This agent showed potent inhibition of placental blood vessel angiogenesis as well as growth inhibition in multiple xenograft models, thus forming the basis for this study. Experimental Design: This study evaluated the toxicity and pharmacokinetics of PI-88 (80-315 mg) when administered s.c. daily for 4 consecutive days bimonthly (part 1) or weekly (part 2). Results: Forty-two patients [median age, 53 years (range, 19-78 years); median performance status, 1] with a range of advanced solid tumors received a total of 232 courses. The maximum tolerated dose was 250 mg/d. Dose-limiting toxicity consisted of thrombocytopenia and pulmonary embolism. Other toxicity was generally mild and included prolongation of the activated partial thromboplastin time and injection site echymosis. The pharmacokinetics were linear with dose. Intrapatient variability was low and interpatient variability was moderate. Both AUC and C-max correlated with the percent increase in activated partial thromboplastin time, showing that this pharmacodynamic end point can be used as a surrogate for drug exposure, No association between PI-88 administration and vascular endothelial growth factor or basic fibroblast growth factor levels was observed. One patient with melanoma had a partial response, which was maintained for >50 months, and 9 patients had stable disease for >= 6 months. Conclusion: The recommended dose of PI-88 administered for 4 consecutive days bimonthly or weekly is 250 mg/d. PI-88 was generally well tolerated. Evidence of efficacy in melanoma supports further evaluation of PI-88 in phase II trials.

Entanglement and boundary critical phenomena

We investigate boundary critical phenomena from a quantum-information perspective. Bipartite entanglement in the ground state of one-dimensional quantum systems is quantified using the Renyi entropy S-alpha, which includes the von Neumann entropy (alpha -> 1) and the single-copy entanglement (alpha ->infinity) as special cases. We identify the contribution of the boundaries to the Renyi entropy, and show that there is an entanglement loss along boundary renormalization group (RG) flows. This property, which is intimately related to the Affleck-Ludwig g theorem, is a consequence of majorization relations between the spectra of the reduced density matrix along the boundary RG flows. We also point out that the bulk contribution to the single-copy entanglement is half of that to the von Neumann entropy, whereas the boundary contribution is the same.

MODELOS DE GOVERNANÇA DE TECNOLOGIA DA INFORMAÇÃO ADOTADOS NO BRASIL - UM ESTUDO DE CASOS MÚLTIPLOS

O tema Governança de Tecnologia da Informação (GTI) tornou-se mais premente no ambiente empresarial brasileiro, principalmente após as repercussões mundiais ocorridas com a queda da bolsa de valores americana Nasdaq, com a nova configuração mundial após os ataques aos Estados Unidos em 11 de setembro de 2001 e a partir da promulgação da Lei Sarbanes-Oxley em 2002. Esse modelo de gestão tem sido implementado por organizações que buscam não somente obter melhor controle de gestão em Tecnologia da Informação, como para aquelas que têm de atender às conformidades legais exigidas pelos órgãos de controle. Implementá-la é um processo complexo e desafiador em virtude da necessidade de se identificar o melhor modelo de GTI dentre as práticas existentes no mundo empresarial. As empresas precisam fazer uma composição daquelas que melhor se aderem às suas realidades. Este trabalho tem como objetivo analisar os modelos de GTI adotados em organizações no Brasil, avaliar os seus resultados, seus níveis de maturidade, os seus benefícios, suas dificuldades e suas tendências, contribuindo assim para o seu melhor entendimento e para amenizar a carência de estudos nessa área no Brasil. Este estudo, que é de natureza empírica, baseou-se na metodologia de estudo de casos múltiplos realizado em cinco empresas para explorar como este modelo de gestão vem sendo adotado, quais estruturas, metodologias e práticas de mercado têm sido utilizadas para a sua efetividade. Neste contexto, apresentam-se os resultados obtidos, os aspectos que envolvem a implementação dos modelos de GTI nas organizações, as dificuldades encontradas, o que têm condicionado o seu desempenho e suas tendências.

Designing a Computer Vision System for Underwater Robotic Interventions

This thesis deals with the challenging problem of designing systems able to perceive objects in underwater environments. In the last few decades research activities in robotics have advanced the state of art regarding intervention capabilities of autonomous systems. State of art in fields such as localization and navigation, real time perception and cognition, safe action and manipulation capabilities, applied to ground environments (both indoor and outdoor) has now reached such a readiness level that it allows high level autonomous operations. On the opposite side, the underwater environment remains a very difficult one for autonomous robots. Water influences the mechanical and electrical design of systems, interferes with sensors by limiting their capabilities, heavily impacts on data transmissions, and generally requires systems with low power consumption in order to enable reasonable mission duration. Interest in underwater applications is driven by needs of exploring and intervening in environments in which human capabilities are very limited. Nowadays, most underwater field operations are carried out by manned or remotely operated vehicles, deployed for explorations and limited intervention missions. Manned vehicles, directly on-board controlled, expose human operators to risks related to the stay in field of the mission, within a hostile environment. Remotely Operated Vehicles (ROV) currently represent the most advanced technology for underwater intervention services available on the market. These vehicles can be remotely operated for long time but they need support from an oceanographic vessel with multiple teams of highly specialized pilots. Vehicles equipped with multiple state-of-art sensors and capable to autonomously plan missions have been deployed in the last ten years and exploited as observers for underwater fauna, seabed, ship wrecks, and so on. On the other hand, underwater operations like object recovery and equipment maintenance are still challenging tasks to be conducted without human supervision since they require object perception and localization with much higher accuracy and robustness, to a degree seldom available in Autonomous Underwater Vehicles (AUV). This thesis reports the study, from design to deployment and evaluation, of a general purpose and configurable platform dedicated to stereo-vision perception in underwater environments. Several aspects related to the peculiar environment characteristics have been taken into account during all stages of system design and evaluation: depth of operation and light conditions, together with water turbidity and external weather, heavily impact on perception capabilities. The vision platform proposed in this work is a modular system comprising off-the-shelf components for both the imaging sensors and the computational unit, linked by a high performance ethernet network bus. The adopted design philosophy aims at achieving high flexibility in terms of feasible perception applications, that should not be as limited as in case of a special-purpose and dedicated hardware. Flexibility is required by the variability of underwater environments, with water conditions ranging from clear to turbid, light backscattering varying with daylight and depth, strong color distortion, and other environmental factors. Furthermore, the proposed modular design ensures an easier maintenance and update of the system over time. Performance of the proposed system, in terms of perception capabilities, has been evaluated in several underwater contexts taking advantage of the opportunity offered by the MARIS national project. Design issues like energy power consumption, heat dissipation and network capabilities have been evaluated in different scenarios. Finally, real-world experiments, conducted in multiple and variable underwater contexts, including open sea waters, have led to the collection of several datasets that have been publicly released to the scientific community. The vision system has been integrated in a state of the art AUV equipped with a robotic arm and gripper, and has been exploited in the robot control loop to successfully perform underwater grasping operations.

Interaction of liquid copper with sintered iron compacts

Interaction of liquid copper with sintered iron is important in brazing, liquid phase sintering and infiltration. In brazing, the penetration of liquid copper into the pores is to be `avoided', whereas in infiltration processes it is `encouraged', and in liquid phase sintering it should be `controlled' so that optimum mechanical properties are achieved. The main objective of the research is to model the interaction by studying the effect of the process variables on the mechanisms of copper interaction in Fe-Cu and Fe-Cu-C systems. This involves both theoretical and experimental considerations. Dilatometric investigations at 950, 1125 and 1200oC, together with metallographic analyses were carried out to clarify the copper growth phenomenon. It is shown that penetration of liquid copper into the iron grain boundaries is the major cause of dimensional changes. Infiltration profiles revealed that copper penetration between the iron interparticle contact points and along iron grain boundaries is a rapid process. The extent of copper penetration depends on the dihedral angle. Large dihedral angles hinder, and small angles promote copper penetration into the grain boundaries. Dihedral angle analysis shows that the addition of 0.6wt.% graphite reduces the number of zero dihedral angle from 27 to 3o and increases the mean dihedral angle from 9.8 to 41.5o. The dihedral angle was lowest at 1125oC and then increased to higher values as the system approached its equilibrium condition. Elementally mixed (E.M.) Fe-Cu compacts showed a rapid expansion at the copper melting point. However, graphite additions reduced compact growth by increasing the mean dihedral angle. In order to reduce the copper growth phenomenon, iron powder was coated with a thin layer of copper by an immersion coating (I.C.) technique. The dilatometric curves revealed an overall shrinkage in the I.C. compacts compared to their corresponding E.M. compacts. Multiple regression models showed that temperature had the most effect on dimensional changes and density had the most contributing effect upon the copper penetration area in the infiltrated powder metallurgy compacts.

Are lipid ratios less susceptible to change with systemic inflammation than individual lipid components in patients with rheumatoid arthritis?

Rheumatoid arthritis (RA) associates with excess cardiovascular risk and there is a need to assess that risk. However, individual lipid levels may be influenced by disease activity and drug use, whereas lipid ratios may be more robust. A cross-sectional cohort of 400 consecutive patients was used to establish factors that influenced individual lipid levels and lipid ratios in RA, using multiple regression models. A further longitudinal cohort of 550 patients with RA was used to confirm these findings, using generalized estimating equations. Cross-sectionally, higher C-reactive protein (CRP) levels correlated with lower levels of total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), and high-density lipoprotein-cholesterol ([HDL-C] P = .015), whereas lipid ratios did not correlate with CRP. The findings were broadly replicated in the longitudinal data. In summary, the effects of inflammation on individual lipid levels may underestimate lipid-associated cardiovascular disease (CVD) risk in RA, thus lipid ratios may be more appropriate for CVD risk stratification in RA.