1,092 research outputs found
Data for "Strength Evolution of Ice Plume Deposit Analogs of Enceladus and Europa"
No full textThis Excel spreadsheet contains all data necessary to reproduce the work and figures presented in Choukroun et al. GRL 2020 article:
- First tab contains all tabulated Cone Penetration Tests data (Figures 1, 2-a, 3)
- Second tab contains graduated cylinder density data (Table S2)
- Third tab contains the parameters of linear fits of strengthening as function of time at each temperature (from Figure 2-a, used in Figure 2-b)
- Fourth tab contains the parameters of the best fit Arrhenius relationship from the strengthening rate as function of temperature (derived from Figure 2-b, used to extrapolate to Enceladus and Europa conditions in Figure 4
Analysis of Mathieu Equation Stable Solutions in the First Zone of Stability
No full textAbstractThe paper presents the results of a homogeneous Mathieu equation studies. Mathieu equation solutions are oscillations, modulated in amplitude and frequency. In the computational experiments we found dependences of the given oscillations on the ratio of the coefficients. These dependences are shown in graphs that can be used for an approximate estimation of the Mathieu equation solutions without integration
A new sampling system tailored to experimentally-derived mechanical properties of icy analogs for evolved Enceladus surface plume deposits
No full textEnceladus is unique amongst Ocean Worlds in our Solar System: the contents of its internal ocean are continuously emitted to space by its present-day activity, and some of these materials are redeposited on the surface. This tiny moon of Saturn thus presents an opportunity to directly measure the composition of the ocean and seek evidence for habitability (including past or extant life), either by collecting and analyzing plume particles as previously proposed by Discovery and New Frontiers mission concepts, or via more ambitious mission concepts that involve landing, surface sampling and analysis, and potential deployment of subsurface probes to reach the ocean itself (Hofgartner et al., this meeting). However, the low surface gravity (1% of Earth’s) and extreme cryogenic conditions in the South Pole regions (~ 50 K, away from the Tiger Stripes) raises questions: how to best sample the upper ~ 1 cm of the surface around a lander, made of most freshly deposited plume materials? What are the expected properties of these materials, i.e. how fast does sintering proceed and how strong would these materials be as function of their exposure age? We provide answers to these questions via a two-pronged approach. First, we surveyed experimentally the time evolution of mechanical strength of large samples of ice spherules at several temperatures. A custom sample preparation system has been developed to synthesize ice spheres with a grain size distribution of mean ~ 12 microns. The samples are subsequently held at temperatures of -30, -50, and -80 C, over extended periods of time (up to 9 months at time of writing), and their strength is tested at frequent intervals using cone penetration tests. The data obtained to date suggests that the observed temperature dependence of the strength evolution is commensurate with expectations from vapor diffusion. Second, we developed a new sampling system that enables rapid sampling and transfer of surface materials into receptacles. Those receptacles can then deposit the sampled materials into the inlet of an instrument dedicated to analyzing the chemical composition of these materials and seek tracers of past or extant life. The geometry of the system and principles of operation have been established and validated by experimental tests, as well as dynamical simulations
Pensar las escalas para pensar las luchas: Autor: Mathieu UHEL
No full textA través de un título sugerente, “pensar las escalas para pensar las luchas”, Mathieu Uhel entreteje la construcción teórico-crítica del concepto escala, generada por la geografía radical anglosajona de finales del siglo XX, con la necesidad/utilidad práctica de la escala para concienciar las luchas sociales. El artículo cumple un doble propósito: por un lado, delinear los elementos de lectura sobre el concepto escala; y, con ello, promover la atención de esta problemática en las luchas contemporáneas. En un primer apartado, Uhel ubica las discusiones académicas en torno a la escala, como herramienta metodológica útil para comprender la complejidad de las sociedades capitalistas; en el segundo apartado, el autor avanza la exposición en torno al contexto de la dimensión escalar del imperialismo capitalista; finalmente, el autor se centra en el rol de la actividad política a escala nacional en la tensa relación entre las imposiciones del capital y la lucha social.Por meio de um título sugestivo, “pensando escalas para pensar lutas”, Mathieu Uhel entrelaça a construção teórico-crítica do conceito de escala, gerado pela geografia radical anglo-saxônica do final do século XX, com a necessidade / utilidade prática escala para aumentar a consciência das lutas sociais. O artigo tem um duplo propósito: por um lado, delinear os elementos de leitura sobre o conceito de escala; e, com isso, promover atenção a esse problema nas lutas contemporâneas. Na primeira seção, Uhel localiza as discussões acadêmicas em torno da escala, como uma ferramenta metodológica útil para compreender a complexidade das sociedades capitalistas; na segunda seção, o autor avança a exposição em torno do contexto da dimensão escalar do imperialismo capitalista; por fim, o autor enfoca o papel da atividade política em escala nacional na tensa relação entre as imposições do capital e a luta social.Mathieu Uhel\u27s suggestive title, “Thinking about scales to think about struggles”, he interweaves the theoretical-critical construction of concept scale, generated by radical Anglo-Saxon geography in the late 20th century, with it´s practical utility to social struggles. The article serves two purposes: on the one hand, Uhel locates academic discussion around scale; and, with this, he promotes attention to this problem in contemporary struggles. In the first section, Uhel locates academic discussions around scale, as a useful methodological tool to understand the complexity of capitalist societies; in the second section, the author advances the argument around the context of the scalar dimension of capitalist imperialism; finally, the author focuses on the role of political activity on a national scale in the tense relationship between the impositions of capital and the social movement
Raman and X-Ray Diffraction Data for Acetylene Clathrate
No full textData behind figures for J. Phys. Chem. A 2019, 123, 7051-7056Related Publication:
Raman Signatures and Thermal Expansivity of Acetylene Clathrate Hydrate
Tuan H. Vu, Robert Hodyss, Morgan L. Cable, Mathieu Choukroun Caltech / JPL
The Journal of Physical Chemistry A
2019-07-16
https://doi.org/10.1021/acs.jpca.9b04426
en
Mathieu Ichou, Les Enfants d’immigrés à l’école
No full textIt is common to hear in the fields of educational and immigration sociology that on average, the children of immigrants do not perform as well in school as children of native-born parents. Mathieu Ichou offers an innovative sociological analysis on a topic that is heavily exploited by political and media discourse, and subject to much scientific controversy. The author takes distance from the homogenized vision of a “second generation” of students who have totally failed academically, and rep..
Formation Kinetics of Ethane Clathrate on Titan
No full textData behind figures for "Rapid Formation of Clathrate Hydrate From Liquid Ethane and Water Ice on Titan," published in Geophysical Research Letters on Jan 29, 2020Related Publication:
Rapid Formation of Clathrate Hydrate from Liquid Ethane and Water Ice on Titan
Tuan H. Vu, Mathieu Choukroun, Christophe Sotin, Victoria Munoz-Iglesias, Helen E. Maynard-Casely
Geophysical Research Letters
2020-01-29
https://doi.org/10.1029/2019GL086265
en
L'impatto dell'attività tintoria sull'ambiente. Firenze alla fine del Medioevo
No full textThe author aims to examine and categorize the range of dyeings materials used in the Florentine wool and silk textile industries in the late Middle Ages, focusing mainly on those produced within the regional space in order to evaluate the impact of the Florentine dyeing activity on the natural environment and the productive landscape of the Tuscan countryside. In particular, the author establishes a line of demarcation between cultivated and uncultivated resources in order to verify which constitutes an indication of the level of industrial development of medieval textile production. This further focuses on how the transition from the exploitation of wild resources to the exploitation of cultivated resources could reflect a greater degree of economic integration between the countryside and the city and contribute to the formation of a regional economic space
Mathieu de Fossey: su visión del mundo indígena mexicano
No full textThroughout these pages the author shows how Mathieu de Fossey perceived that it was not easy to make indigenous communities fit within the mould of the nation-state which, being based on the liberal and egualitarian ideology, was against the recognition of special regimes, such as those that created a peculiar status for the native population of the American territory during the period of Spanish colonial domination
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