Unusual electron density profiles observed by Cassini radio occultations in Titan's ionosphere: Effects of enhanced magnetospheric electron precipitation?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95188/1/jgra21399.pd

Association of Motivational Climate With Addictive Behaviors Depending on Type of Sport in University Students: Structural Equation Analysis

This research study aims at contrasting a structural model of the associations between the alcohol consumption, tobacco dependence, and the problematic use of video games with motivational climate toward sport depending on the category of sports practiced in a sample of Physical Education university students. The sample consisted of 775 university students from the Autonomous Community of Andalusia (Spain), aged between 21 and 35 (22.22 ± 3.76) years. The instruments used were the Perceived Motivational Climate in Sport Questionnaire (PMCSQ-2), the Alcohol Use Disorders Identification Test (AUDIT), the Fagerström Test for Nicotine Dependence (FTND), and the Questionnaire of Experiences Related to Video Games (QERV) questionnaires. A path model that fitted properly in the multigroup analysis for both categories of sports was used, χ2 = 19.843; gl = 8; p = .011; comparative fit index (CFI) = 0.911; normed fit index (NFI) = 0.903; incremental fit index (IFI) = 0.912; root mean square error approximation (RMSEA) = 0.085. An inverse association was shown between task climate and tobacco consumption in individual sports, being weaker in collective sports. This association is not significant for collective sports, but it is for individual sports for ego climate. However, a positive association was found between ego climate and the use of video games in individual sports, not being significant in the case of collective sports. The importance of promoting motivational climates oriented toward tasks that are based on the practice of collective sports is established, because they could act as protective factors against the development of addictive behavior in university students.This research study has been supported by the Education Innovation Project PID 16-45, named “Implementation of digital resources in the classroom for the development of psychosocial and motivational factors in students of the degree in Primary Education with the speciality in Physical Education,” funded by the University of Granada. Education Innovation Project PIBD Advanced 470, named “Program of teaching intervention in students of the degree in primary education and early childhood education through the use of new technologies for the improvement of the psychosocial factors of the students,” funded by the University of Granada. Project I+D+I “DISPERSA,” with code number TIN2015-67149-C3-R, named “Design of Pervasive Games Based on Learning Experiences Sensitive to Context” funded by the Ministry of Economy and Competitiveness. Precompetitive Research Projects for Young Researchers (PPJI_B-05); Self-plan Research of the University of Granada

Preparación y caracterización de cementos belíticos blancos activados con dopantes alcalinos

Activated white cement clinkers with a theoretical 60% (wt) belite (dicalcium silicate) content were prepared at a temperature 100 ºC lower than used to manufacture conventional white Portland cement clinkers. Activation was achieved by adding variable amounts of K2CO 3 or Na2CO 3 to the raw mixes. Rietveld quantitative analysis of X-ray diffraction findings showed that adding the alkalis stabilized the high temperature belite polymorphs. When 2.0% (wt) of Na2O was added, the composition (by wt) found was 16.4(4)% alpha-C2S, 16.7(8)% alpha’-H-C2S, 23.2(6)% beta-C2S, 32.7(7)% total C3S, 9.5(2)% orthorhombic C3A and 1.50(5)% free lime. Due to the high volatilization rate of K2O under the experimental conditions, it stabilized the alpha-type C2S less effectively than Na2O. A calorimetric study was likewise performed to correlate the phase composition with early age hydration (behaviour).Se han preparado clínkeres blancos activados con un porcentaje en peso teórico de belita (silicato dicálcico) del 60%, a una temperatura 100 ºC menor que los clínkeres Portland blancos convencionales. El proceso de activación se ha llevado a cabo añadiendo a las mezclas crudas cantidades variables de K2CO3 o Na2CO 3. Utilizando la difracción de rayos-X y la metodología de Rietveld se ha comprobado la estabilización a temperatura ambiente de porcentajes variables de los polimorfos de alta temperatura de la belita por la adición de alcalinos. De hecho, al añadir 2,0% en peso de Na2O se ha obtenido 16,4(4)% de alfa-C2S, 16,7(8)% de alfa’-H-C2S, 23,2(6)% de beta-C2S, 32,7(7)% de C3S total, 9,5(2)% de C3A ortorrómbico y 1,50(5)% de cal libre, porcentajes en peso. Se ha comprobado que el grado de volatilización de los alcalinos, en estas condiciones de preparación, ha sido muy acusado para el K2O, lo que ha provocado una menor estabilización de los polimorfos tipo-alfa-C2S. Además, se ha realizado un estudio calorimétrico para correlacionar el ensamblaje de fases con el comportamiento de hidratación a edades tempranas

Unique, non‐Earthlike, meteoritic ion behavior in upper atmosphere of Mars

Interplanetary dust particles have long been expected to produce permanent ionospheric metal ion layers at Mars, as on Earth, but the two environments are so different that uncertainty existed as to whether terrestrial-established understanding would apply to Mars. The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission made the first in situ detection of the continuous presence of Na+, Mg+, and Fe+ at Mars and indeed revealed non-Earthlike features/processes. There is no separation of the light Mg+ and the heavy Fe+ with increasing altitude as expected for gravity control. The metal ions are well-mixed with the neutral atmosphere at altitudes where no mixing process is expected. Isolated metal ion layers mimicking Earth's sporadic E layers occur despite the lack of a strong magnetic field as required at Earth. Further, the metal ion distributions are coherent enough to always show atmospheric gravity wave signatures. All features and processes are unique to Mars

Influence of fly ash blending on hydration and physical behavior of Belite-Alite-Ye'elimite cements

A cement powder, composed of belite, alite and ye’elimite, was blended with 0, 15 and 30 wt% of fly ash and the resulting lended cements were further characterized. During hydration, the presence of fly ash caused the partial inhibition of both AFt degradation and belite reactivity, even after 180 days. The compressive strength of the corresponding mortars increased by increasing the fly ash content (68, 73 and 82 MPa for mortars with 0, 15 and 30 wt% of fly ash, respectively, at 180 curing days), mainly due to the diminishing porosity and pore size values. Although pozzolanic reaction has not been directly proved there are indirect evidences.This work is part of the Ph.D. of D. Londono-Zuluaga funded by Beca Colciencias 646—Doctorado en el exterior and Enlaza Mundos 2013 program grant. Cement and Building materials group (CEMATCO) from National University of Colombia is acknowledged for providing the calorimetric measurements. Funding from Spanish MINECO BIA2017-82391-R and I3 (IEDI-2016-0079) grants, co-funded by FEDER, are acknowledged

Applications of electrified dust and dust devil electrodynamics to Martian atmospheric electricity

Atmospheric transport and suspension of dust frequently brings electrification, which may be substantial. Electric fields of 10 kVm-1 to 100 kVm-1 have been observed at the surface beneath suspended dust in the terrestrial atmosphere, and some electrification has been observed to persist in dust at levels to 5 km, as well as in volcanic plumes. The interaction between individual particles which causes the electrification is incompletely understood, and multiple processes are thought to be acting. A variation in particle charge with particle size, and the effect of gravitational separation explains to, some extent, the charge structures observed in terrestrial dust storms. More extensive flow-based modelling demonstrates that bulk electric fields in excess of 10 kV m-1 can be obtained rapidly (in less than 10 s) from rotating dust systems (dust devils) and that terrestrial breakdown fields can be obtained. Modelled profiles of electrical conductivity in the Martian atmosphere suggest the possibility of dust electrification, and dust devils have been suggested as a mechanism of charge separation able to maintain current flow between one region of the atmosphere and another, through a global circuit. Fundamental new understanding of Martian atmospheric electricity will result from the ExoMars mission, which carries the DREAMS (Dust characterization, Risk Assessment, and Environment Analyser on the Martian Surface)-MicroARES (Atmospheric Radiation and Electricity Sensor) instrumentation to Mars in 2016 for the first in situ measurements

Nighttime ionosphere caused by meteoroid ablation and solar wind electron-proton-hydrogen impact on Mars: MEX observation and modeling

We report that radio science (RS) experiment onboard Mars Express (MEX) has observed three plasma layers in the nighttime ionosphere of Mars at altitudes ~80–100 km, ~120 km, and ~160 km, which are reproduced by model calculation due to impact of meteoroid, solar wind proton, and electron, respectively. The densities of 21 ions (Mg+, Fe+, Si+, MgO+, MgCO2+, MgO2+, MgN2+, FeO+, FeO2+, FeN2+, FeCO2+, SiO+, SiCO2+, SiN2+, SiO2+, CO2+, N2+, O+, O2+, CO+, and NO+) have been computed between altitude 50 km and 200 km. The model shows that all atmospheric ions (CO2+, N2+, O+, CO+, O2+, and NO+) are produced above 100 km due to solar wind electron and proton impact ionizations. The metallic ions are formed between 50 km and 100 km due to ablation of micrometeoroids. It is found that mass ~3.0 × 10−4 g of incoming meteoroid is sufficient for meteor ablation and its characteristic flux ~4.0 × 10−15 cm−2s−1 could produce the nighttime metallic layer observed by MEX. The calculated electron densities are also compared with the occultation measurements made by Mars 4/5 in the nighttime ionosphere of Mars