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The hydrogenation of metal nanoparticles provides a pathway toward tuning their combustion characteristics. Metal hydrides have been employed as solid-fuel additives for rocket propellants, pyrotechnics, and explosives. Gas generation during combustion is beneficial to prevent aggregation and sintering of particles, enabling a more complete fuel utilization. Here, we discuss a novel approach for the synthesis of magnesium hydride nanoparticles based on a two-step aerosol process. Mg particles are first nucleated and grown via thermal evaporation, followed immediately by in-flight exposure to a hydrogen-rich low-temperature plasma. During the second step, atomic hydrogen generated by the plasma rapidly diffuses into the Mg lattice, forming particles with a significant fraction of MgH2. We find that hydrogenated Mg nanoparticles have an ignition temperature that is reduced by ∼200 °C when combusted with potassium perchlorate as an oxidizer, compared to the non-hydrogenated Mg material. This is due to the release of hydrogen from the fuel, jumpstarting its combustion. In addition, characterization of the plasma processes suggests that a careful balance between the dissociation of molecular hydrogen and heating of the nanoparticles must be achieved to avoid hydrogen desorption during production and achieve a significant degree of hydrogenation.

Vaping (the use of an e-cigarette) is a common practice among teenagers; 26.7% of high school students report vaping in the last 30 days (Johnston, Miech, O'Malley, Bachman, Schulenberg, and Patrick 2019), making this issue highly relevant. In order to make an informed decision about the use of e-cigarettes, students need to understand the impacts of vaping on their body, which makes the science content engaging and meaningful. Socio-scientific issues (SSI) are real-world issues with clear ties to science ideas and societal concerns, such climate change, resource management, and antibiotic resistance (Sadler, 2004). Using an SSI approach to teaching science can result in increased student learning in science content, nature of science ideas, and understanding of science practices (Eastwood, Sadler, Zeidler, Lewis, and Applebaum, 2012; Klosterman and Sadler, 2010; Zangori, Peel, Kinslow, Friedrichsen, and Sadler, 2017). This article describes a high school biology unit which uses the issue of e-cigarette regulation to teach homeostasis, feedback loops, body system hierarchy, and macromolecules. In order to make an informed decision about the use of e-cigarettes, students need to understand the impacts of vaping on their body, which makes the science content engaging and meaningful.

In the face of growing diversity in marital and cohabiting relationships, the impact of romantic partnerships on criminal desistance may likewise have grown complex. This study investigates how premarital cohabitation and serial cohabitation might influence criminal behavior. We also examine the role of gender in the desistance process. Using data from the National Longitudinal Study of Adolescent to Adult Health, we find that married men who cohabited with the spouse before marriage tended to commit more crimes than those who did not, whereas among married women premarital cohabitation was not associated with an increase in crime. In contrast, serial cohabitation's effect did not vary by gender—male and female serial cohabitors both committed more crimes than one-time cohabitors. We conduct analyses to address selection and the findings are robust. Our work suggests that exploring heterogeneity within changing patterns of marriage and cohabitation is critical to understanding desistance from crime. [ABSTRACT FROM AUTHOR]

The General Educational Development (GED) degree is designed to be a credential equivalent to the high school diploma. However, growing evidence indicates that GED recipients have worse outcomes than high school graduates. Such findings raise the question: is the GED socially equivalent to the high school diploma? Although educational assortative mating patterns have long been used as a barometer of the social distance across educational groups, there has not been a study that has addressed this question by examining the marital sorting patterns of GED recipients. Using log-linear models, our study shows that the odds of intermarriage between GED recipients and high school graduates resemble those between GED recipients and those without a secondary degree. Racial/ethnic minorities had greater difficulty crossing the GED/high school graduate boundary when they married. Our findings detract from the purported view that the GED degree is equivalent to a traditional high school diploma. [ABSTRACT FROM AUTHOR]

Magnesium is a promising candidate as a solid fuel for energetic applications, however, the diffusion‐controlled oxidation mechanism impedes its reaction with an oxidizer, often resulting in diminished performance. In this study, non‐thermal plasma processing is implemented to modify the surface of magnesium nanoparticles with silicon in‐flight, in the gas‐phase to enhance the rate of interfacial reactions and tune the ignition pathways. Allowing the silicon coating to partially oxidize provides direct contact between the fuel and oxidizer, resulting in a nanostructured thermite system at the single particle level. The proximal distance between oxidizer and fuel directly impacts the ignition temperature and, therefore, the combustion kinetics. An intermetallic reaction occurs within the magnesium/silicon system to supplement the heating of the magnesium fuel to initiate its reaction with the oxidizer, resulting in highly reduced ignition thresholds. The ignition temperature is lowered significantly from ≈740 °C for magnesium particles with a native oxide layer to ≈520 °C for particles coated via the in‐flight plasma process. [ABSTRACT FROM AUTHOR]