Analisando a possibilidade de um anel ao redor de um satélite

On November 26 th, 2005, Rhea, one of Saturn's moons, is found by Cassini spacecraft approximately at 5.105 km from Saturn. Observations in situ reveal that electrons are depleted in the moon's vicinity. However, Rhea is considered massive enough to retain a thin atmosphere. Assumption was that the atmosphere of Rhea was not composed exclusively of gas, its likely contains solid material that can absorb magnetospheric particles. According to Jones et al. (2008), these particles were in a speci c position so that at the moment of observation the electrons could not be detected. In opposition to this idea there is a group, Tiscareno et al. 2010, Cornell University Library, that underwent intensive search for any material that might be orbiting Rhea using Cassini images, however the could not identify any. Second recommendation made by American researchers and other countries, and accepted by the National Board of Research the Cassini Equinox Mission will continue in orbit around Saturn until 2016.The probe will perform several maneuvers with high inclination to delve into the main ring system, and then enter in Saturn's atmosphere and collide with planet. This research is of great importance because until today no rings were found orbiting satellites. The goal of this work is to analyze the orbital evolution of a set of particles around Rhea disturbance of Saturn, J2 e J4 and check results by the numerical simulations and the possibility of a stable ring orbiting Rhea.

Two fluid numerical model for coastal applications

Wave breaking is an important coastal process, influencing hydro-morphodynamic processes such as turbulence generation and wave energy dissipation, run-up on the beach and overtopping of coastal defence structures. During breaking, waves are complex mixtures of air and water (“white water”) whose properties affect velocity and pressure fields in the vicinity of the free surface and, depending on the breaker characteristics, different mechanisms for air entrainment are usually observed. Several laboratory experiments have been performed to investigate the role of air bubbles in the wave breaking process (Chanson & Cummings, 1994, among others) and in wave loading on vertical wall (Oumeraci et al., 2001; Peregrine et al., 2006, among others), showing that the air phase is not negligible since the turbulent energy dissipation involves air-water mixture. The recent advancement of numerical models has given valuable insights in the knowledge of wave transformation and interaction with coastal structures. Among these models, some solve the RANS equations coupled with a free-surface tracking algorithm and describe velocity, pressure, turbulence and vorticity fields (Lara et al. 2006 a-b, Clementi et al., 2007). The single-phase numerical model, in which the constitutive equations are solved only for the liquid phase, neglects effects induced by air movement and trapped air bubbles in water. Numerical approximations at the free surface may induce errors in predicting breaking point and wave height and moreover, entrapped air bubbles and water splash in air are not properly represented. The aim of the present thesis is to develop a new two-phase model called COBRAS2 (stands for Cornell Breaking waves And Structures 2 phases), that is the enhancement of the single-phase code COBRAS0, originally developed at Cornell University (Lin & Liu, 1998). In the first part of the work, both fluids are considered as incompressible, while the second part will treat air compressibility modelling. The mathematical formulation and the numerical resolution of the governing equations of COBRAS2 are derived and some model-experiment comparisons are shown. In particular, validation tests are performed in order to prove model stability and accuracy. The simulation of the rising of a large air bubble in an otherwise quiescent water pool reveals the model capability to reproduce the process physics in a realistic way. Analytical solutions for stationary and internal waves are compared with corresponding numerical results, in order to test processes involving wide range of density difference. Waves induced by dam-break in different scenarios (on dry and wet beds, as well as on a ramp) are studied, focusing on the role of air as the medium in which the water wave propagates and on the numerical representation of bubble dynamics. Simulations of solitary and regular waves, characterized by both spilling and plunging breakers, are analyzed with comparisons with experimental data and other numerical model in order to investigate air influence on wave breaking mechanisms and underline model capability and accuracy. Finally, modelling of air compressibility is included in the new developed model and is validated, revealing an accurate reproduction of processes. Some preliminary tests on wave impact on vertical walls are performed: since air flow modelling allows to have a more realistic reproduction of breaking wave propagation, the dependence of wave breaker shapes and aeration characteristics on impact pressure values is studied and, on the basis of a qualitative comparison with experimental observations, the numerical simulations achieve good results.

L'idea di metafora nell'opera di Oswald Mathias Ungers

This research focuses on the definition of the complex relationship that exists between theory and project, which - in the architectural work by Oswald Mathias Ungers - is based on several essays and on the publications that - though they have never been collected in an organic text - make up an articulated corpus, so that it is possible to consider it as the foundations of a theory. More specifically, this thesis deals with the role of metaphor in Unger’s theory and its subsequent practical application to his projects. The path leading from theoretical analysis to architectural project is in Ungers’ view a slow and mediated path, where theory is an instrument without which it would not be possible to create the project's foundations. The metaphor is a figure of speech taken from disciplines such as philosophy, aesthetics, linguistics. Using a metaphor implies a transfer of meaning, as it is essentially based on the replacement of a real object with a figurative one. The research is articulated in three parts, each of them corresponding to a text by Ungers that is considered as crucial to understand the development of his architectural thinking. Each text marks three decades of Ungers’ work: the sixties, seventies and eighties. The first part of the research deals with the topic of Großform expressed by Ungers in his publication of 1966 Grossformen im Wohnungsbau, where he defines four criteria based on which architecture identifies with a Großform. One of the hypothesis underlying this study is that there is a relationship between the notion of Großform and the figure of metaphor. The second part of the thesis analyzes the time between the end of the sixties and the seventies, i.e. the time during which Ungers lived in the USA and taught at the Cornell University of Ithaca. The analysis focuses on the text Entwerfen und Denken in Vorstellungen, Metaphern und Analogien, written by Ungers in 1976, for the exhibition MAN transFORMS organized in the Cooper - Hewitt Museum in New York. This text, through which Ungers creates a sort of vocabulary to explain the notions of metaphor, analogy, signs, symbols and allegories, can be defined as the Manifesto of his architectural theory, the latter being strictly intertwined with the metaphor as a design instrument and which is best expressed when he introduces the 11 thesis with P. Koolhaas, P. Riemann, H. Kollhoff and A. Ovaska in Die Stadt in der Stadt in 1977. Berlin das grüne Stadtarchipel. The third part analyzes the indissoluble tie between the use of metaphor and the choice of the topic on which the project is based and, starting from Ungers’ publication in 1982 Architecture as theme, the relationship between idea/theme and image/metaphor is explained. Playing with shapes requires metaphoric thinking, i.e. taking references to create new ideas from the world of shapes and not just from architecture. The metaphor as a tool to interpret reality becomes for Ungers an inquiry method that precedes a project and makes it possible to define the theme on which the project will be based. In Ungers’ case, the architecture of ideas matches the idea of architecture; for Ungers the notions of idea and theme, image and metaphor cannot be separated from each other, the text on thematization of architecture is not a report of his projects, but it represents the need to put them in order and highlight the theme on which they are based.

Seismic Serviceability Assessment of Water Distribution Systems

Water distribution systems are important for life saving facilities especially in the recovery after earthquakes. In this paper, a framework is discussed about seismic serviceability of water systems that includes the fragility evaluation of water sources of water distribution networks. Also, a case study is brought about the performance of a water system under different levels of seismic hazard. The seismic serviceability of a water supply system provided by EPANET is evaluated under various levels of seismic hazard. Basically, the assessment process is based on hydraulic analysis and Monte Carlo simulations, implemented with empirical fragility data provided by the American Lifeline Alliance (ALA, 2001) for both pipelines and water facilities. Represented by the Seismic Serviceability Index (Cornell University, 2008), the serviceability of the water distribution system is evaluated under each level of earthquakes with return periods of 72 years, 475 years, and 2475 years. The system serviceability under levels of earthquake hazard are compared with and without considering the seismic fragility of the water source. The results show that the seismic serviceability of the water system decreases with the growing of the return period of seismic hazard, and after considering the seismic fragility of the water source, the seismic serviceability decreases. The results reveal the importance of considering the seismic fragility of water sources, and the growing dependence of the system performance of water system on the seismic resilience of water source under severe earthquakes.

Monopsony Power, Pay Structure and Training

Although interest in monopsonistic influences on labor market outcomes has revived in recent years, only a few empirical studies provide direct evidence on this topic. In this article, the authors analyze the effect of monopsony power on pay structure, using a direct measure of labor market thinness. The authors find evidence of monopsony power, as firms facing fewer local competitors offer lower wages to skilled labor and trainees, but not to unskilled labor. The findings have important implications for the economic theory of training, as most recent models assume monopsonistic pay-setting for skilled labor, but not for trainees.

Na 1 Nachlass Max Horkheimer, 11 - Korrespondenzen u.a. mit Edward M. David (p. I 6, 1-183)

1 Brief von Fritz Dannenbaum an Max Horkheimer, 26.11.1935; 2 Briefe zwischen F. Darnbacher und Max Horkheimer, 24.01.1936, 22.01.1936; 3 Briefe zwischen dem Dartmouth College Hanover N.H. und Max Horkheimer, 1939-1941. 06.05.1939; 14 Briefe zwischen Edward M. David und Max Horkheimer, 1941-1942; 1 Brief von der Day Cornell University, Ithaca N.Y. an Max Horkheimer, 24.02.1939; 2 Briefe zwischen Margaret Deaner und Max Horkheimer, 01.04.1935, 04.04.1935; 1 Brief von Max Horkheimer an Hanna Deinhard, 05.01.1949; 1 Brief von Deiters an Max Horkheimer, 26.11.1935; 2 Briefe zwischen Laura Demick und Max Horkheimer, 22.12.1941, 29.12.1941; 2 Briefe zwischen Grace Dertz und Max Horkheimer, 18.10.1934, 11.10.1934; 1 Brief von Max Horkheimer an Dekan, 20.06.1940; 1 Brief von Max Dessoir an Max Horkheimer, 29.08.1937; 1 Brief von Max Horkheimer an Deutschland / deutsches Reich Minister für Wissenschaft, Kunst und Volksbildung, Berli, 21.04.1933; 4 Briefe zwischen John Dewey und Max Horkheimer, 1940-1941, 20.02.1941; 1 Brief von Max Horkheimer an Walter Strauss, 20.02.1941; 3 Briefe zwischen Frederic Dewhurst und Max Horkheimer, 1939, 08.02.1939; 5 Briefe zwischen dem Soziograph Jul Diederich und Max Horkheimer, 1934-1938; 1 Brief von Max Horkheimer an Hugo Sinzheimer, 20.10.1934; 15 Briefe zwischen William Dieterle, Charlotte Dieterle und Max Horkheimer, 1940-1944; 1 Brief von der Dillmann-Oberschule Stuttgart an Max Horkheimer, 13.12.1949; 1 Brief vonMax Horkheimer an W. R. Dittmar, 10.02.1938; 2 Briefe zwischen Sofie Doernberg, Paul Doernberg und Margot von Mendelssohn, 1942, 06.04.1942; 4 Briefe zwischen Willy Dörter und Max Horkheimer, 1936-1937, 20.02.1936; 1 Brief von Georg Glaser anMax Horkheimer; 3 Briefe zwischen Hans Venedey und Max Horkheimer, 22.01.1938, 1938; 28 Briefe sowie Zeitungsausschnitte zwischen Juliette Favez und Max Horkheimer, 1934-1938; 1 Brief von Juliette Favez ann karl Dörter, 02.10.1934; 2 Briefe von Max Horkheimer an Hans Klaus Brill, Januar 1938; 3 Briefe zwischen Karl Dörter und Max Horkheimer, 1934-1937, 12.10.1934; 4 Briefe zwischen Andrés Sternheim und Max Horkheimer, 1937, 16.06.1937; 1 Brief von Else Klee an Max Horkheimer, 13.06.1935;

Identification of maltreatment type in children with disabilities using the National Child Abuse and Neglect Data System (NCANDS)

This study was a retrospective design and used secondary data from the National Child Abuse and Neglect Data System (NCANDS), provided by the National Data Archive on Child Abuse and Neglect Family Life Development Center administered by Cornell University. The dataset contained information for the year 2005 on children from birth to 18 years of age. Child abuse and neglect for disabled children, was evaluated in-depth in the present study. Descriptive and statistical analysis was performed using the children with and without disabilities. It was found that children with disabilities have a lower rate of substantiation that likely indicates the interference of reporting due to their handicap. The results of this research demonstrate the important need to teach professionals and laypersons alike on how to recognize and substantiate abuse among disabled children.^

Influence of Crop Load on Tree Growth, Yield, and Fruit Quality of Scab Resistant Apples at Harvest

Apple scab, caused by Venturia inaequalis, is a major disease affecting apple production. Breeding programs have developed over 30 releases of scab-resistant cultivars since 1970 with recent ones having much improved quality. Redfree and GoldRush are from a cooperative breeding program involving Purdue, Rutgers, and Illinois universities while Liberty was introduced from the Cornell University breeding program. For these cultivars to gain better acceptance, more information is needed on their cropping capacities and the effect of crop load on fruit quality attributes. Our study was conducted to determine the relationship between increasing crop load on tree growth, fruit size, and fruit quality variables of the three cultivars under Iowa conditions.

José Martí entre dos crónicas : presiones editoriales y la autonomía relativa de la producción del escritor modernista

La producción de José Martí como cronista en los Estados Unidos para los diarios latinoamericanos El Partido Liberal, de México, y La Nación, de Argentina, estaba sujeta a diversas políticas editoriales. Hasta ahora estos mecanismos que condicionaban su obra no han sido estudiados para comprender un giro radical en su pensamiento. El 2 de setiembre de 1886, Martí escribió para La Nación una crónica acerca de los trágicos acontecimientos que se desencadenaron en Chicago, tras una protesta de trabajadores. En esa, Martí no duda de la responsabilidad de líderes anarquistas por la muerte de un policía. Sin embargo, en una segunda crónica enviada un año después, Martí presenta un giro radical en su apreciación de los anarquistas y critica las causas que los habían empujado a radicalizar el movimiento obrero. El presente ensayo revela cómo Martí modifica su posición al escribir bajo distintos sistemas de autorización y analiza la estrategia narrativa que emplea el escritor para surcar soterradamente estas presiones. El contenido de la segunda crónica para La Nación es analizado como la materialización de la voluntad autonómica del escritor modernista. Una afirmación que marca un clivaje crucial en su trayectoria que al poco tiempo lo conduciría a participar en la guerra de independencia de Cuba en 1895.