Thermodynamic Modeling of Hydrogen Storage Capacity in Mg-Na Alloys
Thermodynamic modeling of the H-Mg-Na system is performed for the first time in this work in order to understand the phase relationships in this system. A new thermodynamic description of the stable NaMgH3 hydride is performed and the thermodynamic models for the H-Mg, Mg-Na, and H-Na systems are reassessed using the modified quasichemical model for the liquid phase. The thermodynamic properties of the ternary system are estimated from the models of the binary systems and the ternary compound using CALPHAD technique. The constructed database is successfully used to reproduce the pressure-composition isotherms for MgH2 + 10 wt.% NaH mixtures. Also, the pressure-temperature equilibrium diagram and reaction paths for the same composition are predicted at different temperatures and pressures. Even though it is proved that H-Mg-Na does not meet the DOE hydrogen storage requirements for onboard applications, the best working temperatures and pressures to benefit from its full catalytic role are given. Also, the present database can be used for thermodynamic assessments of higher order systems.
Effect of the nanometric LiFePO4 on the hydrogen storage properties of MgH2
Abstract A nanometric phosphoric complex salt additive was synthesized by hydrothermal method. Its catalytic effect on the hydrogen storage properties of MgH 2 was investigated. MgH 2 +20 wt.% LiFePO 4 obtained by ball-milling process had an ability of absorbing 2.03 wt.% hydrogen at 423 K in 21 min, and only 0.98 wt.% could be absorbed by MgH 2 for the identical condition. 3.61 wt.% hydrogen could be released by the composite at 623 K in 21 min, whereas only 2.23 wt.% was desorbed by as-received MgH 2 . Doping by nanometric LiFePO 4 expressively enhanced the hydrogenation/dehydrogenation properties of MgH 2 , and changed the rate-controlling steps from three-dimensional interfacial reaction to one-dimensional diffusion process. Meanwhile, the onset dehydrogenation temperature for MgH 2 +20 wt.% LiFePO 4 was 653 K, which was found to be 60 K lower than the as-received MgH 2 . In addition, the addition of LiFePO 4 also lowered the activation energy ( E a) 31 kJ mol −1 . Based on XRD and XPS analysis, the in situ formed phases LiMgPO 4 and Fe, which are produced by the reaction between MgH 2 and LiFePO 4 , may be responsible for the remarkable improvement in hydrogen storage properties of MgH 2 .
Working Knowledge: Employee Innovation and the Rise of Corporate Intellectual Property, 1800-1930
This book presents the legal and business history of corporate ownership of employee knowledge. Skilled workers of the early nineteenth century enjoyed a degree of professional independence because workplace knowledge and technical skill were their 'property,' or at least their attribute. In most sectors of today's economy, however, it is a foundational and widely accepted truth that businesses retain legal ownership of employee-generated intellectual property. In "Working Knowledge", Catherine Fisk chronicles the legal and social transformations that led to the transfer of ownership of employee innovation from labor to management. This deeply contested development was won at the expense of workers' entrepreneurial independence and ultimately, Fisk argues, economic democracy. By reviewing judicial decisions and legal scholarship on all aspects of employee-generated intellectual property and combing the archives of major nineteenth-century intellectual property - producing companies - including DuPont, Rand McNally, and the American Tobacco Company - Fisk makes a highly technical area of law accessible to general readers while also addressing scholarly deficiencies in the histories of labor, intellectual property, and the business of technology.