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We report the structural transformations of carbon via the melt spinning and subsequent annealing of nickel-carbon alloys. We attained metastable solid solubility of carbon in nickel ribbon by achieving a rapid solidification rate of up to 1.6 × 106 K/s. Excess carbon atoms were found to be dissolved in the nickel lattice causing up to 1.4% strain for an alloy spun at 70 m/s tangential wheel speeds. High temperature heat treatments led to precipitation of carbon from the nickel lattice on the ribbon free surfaces but also led to growth of spherical precipitates within the nickel matrix, an effect consistent with bulk diffusion-driven Ostwald ripening. Carbon was excavated from the ribbons via chemical dissolution of the metal and characterized by electron microscopy and Raman spectroscopy. We found that the microstructure of carbon precipitated from the rapidly quenched ribbon could be tuned by varying the carbon content from 4 to 12 at. % in the precursor and annealing the ribbon at temperatures that ranged from 400 to 1200 °C. Via the step-wise variation of these two parameters, we sequentially transformed amorphous carbon nanospheres with a high BET surface area of 203 m2/g into thick, highly crystalline flakes of graphite that conformed to the shape of the as-spun ribbon.

This article argues that during the first two decades of the twentieth century, William Monroe Trotter’s Boston Guardian challenged “post-truth” politics at the heart of America’s exploitative racial project both at home and abroad. Trotter’s reinvigorated Black radical press exposed a fundamental lie at the heart of American racialization: that lynching, segregation, and violent white domination were natural features of United States exceptionalism, and that “the colored people themselves” (both at home and abroad) were responsible for their own subjugation. Through the Guardian’s campaign against racial disinformation espoused in mainstream Black newspapers, Trotter influenced the New Negro radicalism of Cyril V. Briggs, Hubert Harrison, and the African Blood Brotherhood.

Due to large numbers of students arriving in the U.S. with different religious beliefs/backgrounds, it is necessary to analyze the religious environment of students’ home country and examine how it...

Misrepresenting Race Medical education and practice have not evolved to reflect advances in understanding of the relationships among race, racism, and health. Instead, race remains one of the most ...

El Mapa Geomorfológico de la República de Cuba a escala 1: 100 000, es uno de los proyectos desarrollados por el país para aumentar el grado de conocimiento geológico y optimizar el aprovechamiento de los recursos y condiciones naturales. El mapa lo conforman varias hojas topográficas, entre ellas se encuentra la de Mayarí 5077; la misma posee una elevada complejidad geólogo-estructural, lo que hace necesario profundizar en su conocimiento morfotectónico. Es por ello que se realiza la identificación y caracterización de morfoalineamientos, a partir de métodos morfométricos, análisis de la red de drenaje superficial y fotointerpretación. Los elementos lineales fueron extraídos, empleando el Sistema de Información Geográfica QGIS v3.16, y posteriormente superpuestos y correlacionados para obtener un Mapa final. Se determinó el número, longitud, orientación y densidad de los morfoalineamientos. Como resultado se identificaron 249, con una longitud promedio de 1422 m, orientación predominante N 40º – 50º E y secundaria N 50º – 60º E, asociadas a fallas laterales normales, pertenecientes al principal sistema de fracturación en la región, la dirección Nipe (NE – SO). Además, el análisis de su densidad permitió definir que las laderas noroeste de la Sierra de Nipe, y la zona de articulación de este grupo montañoso con la Sierra Cristal, constituyen las áreas de mayor debilidad tectónica, marcadas por elementos lineales preferentemente diagonales, que siguen la orientación de fallas y límites de morfoestructuras. La génesis del relieve del área de estudio está fuertemente condicionada por estructuras tectónicas, que han influido directamente en la intensidad de la actividad exogenética.