Experimental study on shrinkage behaviour and prediction of shrinkage magnitudes of residual soils

The present study examines the shrinkage behaviour of residually derived black cotton (BC) soil and red soil compacted specimens that were subjected to air-drying from the swollen state. The soil specimens were compacted at varying dry density and moisture contents to simulate varied field conditions. The void ratio and moisture content of the swollen specimens were monitored during the drying process and relationship between them is analyzed. Shrinkage is represented as reduction in void ratio with decrease in water content of soil specimens. It is found to occur in three distinct stages. Total shrinkage magnitude depends on the type of clay mineral present. Variation in compaction conditions effect marginally total shrinkage magnitudes of BC soil specimens but have relatively more effect on red soil specimens. A linear relation is obtained between total shrinkage magnitude and volumetric water content of soil specimens in swollen state and can be used to predict the shrinkage magnitude of soils.

Influence of Switching Conditions on the VETO Magnitudes in a GIS

Estimation of very fast transient overvoltage (VFTO) has been carried out using EMTP for various switching conditions in a 420 kV gas-insulated substation (GIS). The variation of the VFTO peak along the GIS bus nodes for disconnector and circuit breaker switching operations, as well as the variation of VFTO peak with different magnitudes of trapped charges, have been studied. The results indicate a distinct pattern of variation of VFTO peak along the nodes of the GIS bus in the case of disconnector switch operation as compared to that of circuit-breaker operation. It has also been noticed that the variation of VFTO peak levels are not in direct proportion to the trapped charge present on the HV bus.

RES-TOCSY: A facile approach for accurate determination of magnitudes, and relative signs of (n)J(HF)

The RES-TOCSY experiment for accurate determination of heteronuclear (n)J(HF) is reported. The main feature of the proposed technique is the accurate measurement of magnitudes of heteronuclear couplings from the displacement of cross sections of the 2D spectrum and their relative signs from the slopes of their displacement vectors. The experiment is highly advantageous as the couplings of smaller magnitudes hidden within line widths could also be accurately determined, and also in situations when the spectrum does not display any coupling fine structures. The efficient utility of the developed pulse sequence is unambiguously established on fluorine containing aromatic and aliphatic molecules. (C) 2014 Elsevier B.V. All rights reserved.

Problemas de estimación de magnitudes no alcanzables: estrategias y éxito en la resolución

Llamamos problemas de Fermi a aquellos problemas que, siendo de difícil resolución, admiten una aproximación a su solución a base de romper el problema en partes más pequeñas y resolverlas por separado. En este artículo presentamos los problemas de estimación de magnitudes no alcanzables (PEMNA) como un subconjunto de los problemas de Fermi. A partir de los datos recopilados en un estudio hecho con alumnos de 12 a 16 años, caracterizamos las distintas estrategias de resolución propuestas por estos y discutimos sobre la potencialidad de estas estrategias para resolver los problemas con éxito.

Absolute Magnitudes of Pan-STARRS PS1 Asteroids

Absolute magnitude (H) of an asteroid is a fundamental parameter describing the size and the apparent brightness of the body. Because of its surface shape, properties and changing illumination, the brightness changes with the geometry and is described by the phase function governed by the slope parameter (G). Although many years have been spent on detailed observations of individual asteroids to provide H and G, vast majority of minor planets have H based on assumed G and due to the input photometry from multiple sources the errors of these values are unknown. We compute H of ~ 180 000 and G of few thousands asteroids observed with the Pan-STARRS PS1 telescope in well defined photometric systems. The mean photometric error is 0.04 mag. Because on average there are only 7 detections per asteroid in our sample, we employed a Monte Carlo (MC) technique to generate clones simulating all possible rotation periods, amplitudes and colors of detected asteroids. Known asteroid colors were taken from the SDSS database. We used debiased spin and amplitude distributions dependent on size, spectral class distributions of asteroids dependent on semi-major axis and starting values of G from previous works. H and G (G12 respectively) were derived by phase functions by Bowell et al. (1989) and Muinonen et al. (2010). We confirmed that there is a positive systematic offset between H based on PS1 asteroids and Minor Planet Center database up to -0.3 mag peaking at 14. Similar offset was first mentioned in the analysis of SDSS asteroids and was believed to be solved by weighting and normalizing magnitudes by observatory codes. MC shows that there is only a negligible difference between Bowell's and Muinonen's solution of H. However, Muinonen's phase function provides smaller errors on H. We also derived G and G12 for thousands of asteroids. For known spectral classes, slope parameters agree with the previous work in general, however, the standard deviation of G in our sample is twice as larger, most likely due to sparse phase curve sampling. In the near future we plan to complete the H and G determination for all PS1 asteroids (500,000) and publish H and G values online. This work was supported by NASA grant No. NNX12AR65G.

Absolute Magnitudes of Pan-STARRS 1 Asteroids

It is well known that the absolute magnitudes (H) in the MPCORB and ASTORB orbital element catalogs suffer from a systematic offset. Juric at al. (2002) found 0.4 mag offset in the SDSS data and detailed light curve studies of WISE asteroids by Pravec et al. (2012) revealed size-dependent offsets of up to 0.5 mag. The offsets are thought to be caused by systematic errors introduced by earlier surveys using different photometric catalogs and filters. The next generation asteroid surveys provide an order of magnitude more asteroids and well-defined and calibrated magnitudes. The Pan-STARRS 1 telescope (PS1) has observed hundreds of thousands asteroids, submitted more than 2 million detections to the Minor Planet Center (MPC) and discovered almost 300 NEOs since the beginning of operations in late 2010. We transformed the observed apparent magnitudes of PS1-detected asteroids from the gP1,rP1,iP1,yP1,zP1 and wP1-bands into Johnson photometric system by assuming the mean S and C-type asteroid color (Fitzsimmons 2011 - personal communication, Schlafly et al. 2012, Magnier et al. 2012 - in preparation) and calculated the absolute magnitude (H) in the V-band and its uncertainty (Bowell et al., 1989) for more than 200,000 known asteroids having on average 6.7 detections per object. The H error with respect to the MPCORB catalog revealed a mean offset of -0.49+0.30 mag in good agreement with published values. We will also discuss the statistical and systematical errors in H and slope parameter G.

Absolute magnitudes and slope parameters of Pan-STARRS PS1 asteroids -preliminary results

We present the study of absolute magnitude (H) and slope parameter (G) of 170,000 asteroids observed by the Pan-STARRS1 telescope during the period of 15 months within its 3-year all-sky survey mission. The exquisite photometry with photometric errors below 0.04 mag and well-defined filter and photometric system allowed to derive H and G with statistical and systematic errors. Our new approach lies in the Monte Carlo technique simulating rotation periods, amplitudes, and colors, and deriving most-likely H, G and their systematic errors. Comparison of H_M by Muinonen's phase function (Muinonen et al., 2010) with the Minor Planet Center database revealed a negative offset of 0.22±0.29 meaning that Pan-STARRS1 asteroids are fainter. We showed that the absolute magnitude derived by Muinonen's function is systematically larger on average by 0.14±0.29 and by 0.30±0.16 when assuming fixed slope parameter (G=0.15, G_{12}=0.53) than Bowell's absolute magnitude (Bowell et al., 1989). We also derived slope parameters of asteroids of known spectral types and showed a good agreement with the previous studies within the derived uncertainties. However, our systematic errors on G and G_{12} are significantly larger than in previous work, which is caused by poor temporal and phase coverage of vast majority of the detected asteroids. This disadvantage will vanish when full survey data will be available and ongoing extended and enhanced mission will provide new data.

Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - preliminary results

We present the results of a Monte Carlo technique to calculate the absolute magnitudes (H) and slope parameters (G) of about 240,000 asteroids observed by the Pan-STARRS1 telescope during the first 15 months of its 3-year all-sky survey mission. The system's exquisite photometry with photometric errors asteroids rotation period, amplitude and color to derive the most-likely H and G, but its major advantage is in estimating realistic statistical+systematic uncertainties and errors on each parameter. The method was confirmed by comparison with the well-established and accurate results for about 500 asteroids provided by Pravec et al. (2012) and then applied to determining H and G for the Pan-STARRS1 asteroids using both the Muinonen et al. (2010) and Bowell et al. (1989) phase functions. Our results confirm the bias in MPC photometry discovered by ( Jurić et al., 2002).

Evaluaci??n de tres medidas de la sensibilidad en tareas de estimaci??n de magnitudes

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Sistema di??drico. Poliedros regulares : secciones planas y sus verdaderas magnitudes

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Nomenclatura, símbolos y escritura de las magnitudes fisicoquímicas.

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Lo matemático en el diseño y análisis de organizaciones didácticas : los sistemas de numeración y la medida de magnitudes.

Mostrar la necesidad de relacionar los aspectos matemático y didáctico en los procesos de enseñanza y estudio de las Matemáticas. Alumnos de 3õ de ESO y de 2õ de Magisterio en la Facultad de Educación de la Universidad Complutense de Madrid. Se trabaja en dos ámbitos. Por un lado, la enseñanza de los sistemas de numeración en Educación Primaria, ESO y la carrera de Magisterio. Y por otro, la enseñanza de la medida de magnitudes continuas en el último curso de Educación Primaria. En ambos casos se utiliza la Teoría de Situaciones Didácticas para construir un Modelo Epistemológico de Referencia. Este modelo consiste en una secuencia de praxeologías de complejidad creciente, dentro del marco de la Teoría Antropológica de lo Didáctico. El Modelo Epistemológico de Referencia sirve de guía para el análisis de la enseñanza en Matemáticas recibida por los alumnos de Magisterio; para el diseño, experimentación, análisis y evaluación de dos organizaciones didácticas en Magisterio y en ESO; para reconstruir y analizar una organización didáctica en torno a los sistemas de numeración dentro del primer ciclo de Educación Primaria; y para estudiar e interpretar la estructura de una organización didáctica en el campo de la medida de magnitudes. Se utilizan los trabajos desarrollados por Guy Brousseau y sus colaboradores en el ámbito de la Teoría de Situaciones Didácticas. Estas propuestas son interpretadas desde el punto de vista de la Teoría Antropológica de lo Didáctico. El método utilizado en la investigación es empírico. La investigación pone de manifiesto la complementariedad entre la Teoría de Situaciones Didácticas y la Teoría Antropológica de lo Didáctico, y la necesidad de avanzar en el proceso de integración de ambas. Se proponen dos Modelos Epistemológicos de Referencia que pueden ser utilizados en el ámbito del diseño, gestión y evaluación de las organizaciones didácticas y en el campo de la investigación didáctica. Uno de ellos está relacionado con los sistemas de numeración y el otro, con la medida de magnitudes. Además, la consideración de los Modelos Epistemológicos de Referencia como objetos de estudio en sí mismos permite la formulación de un nuevo tipo de problemas didácticos.

Un enfoque creativo de las magnitudes y su medida para educación infantil.

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Proporcionalidad de magnitudes : metodología matemática.

Se presentan algunas de las aplicaciones prácticas sobre la cuestión teórica y conceptual de la proporcionalidad de magnitudes. Primeramente se hace una breve reseña histórica y se precisa en concepto de magnitud. A continuación, se precisan algunos puntos de interés: las magnitudes escalares, las magnitudes escalares continuas y sus propiedades, la divisibilidad de una magnitud, la proporcionalidad entre magnitudes, la caracterización de la proporcionalidad, la medición indirecta de cantidades, la proporción entre cantidades, y la proporción numérica. El objetivo es iniciar a los alumnos de bachillerato en los primeros pasos de la Matemática elemental.