Thermal stress-induced charge and structure heterogeneity in emerging cathode materials

Nickel-rich layered oxide cathode materials are attractive near-term candidates for boosting the energy density of next generation lithium-ion batteries. The practical implementation of these materials is, however, hindered by unsatisfactory capacity retention, poor thermal stability, and oxygen release as a consequence of structural decomposition, which may have serious safety consequences. The undesired side reactions are often exothermic, causing complicated electro-chemo-mechanical interplay at elevated temperatures. In this work, we explore the effects of thermal exposure on chemically delithiated LiNi0.8Mn0.1Co0.1O2 (NMC-811) at a practical state-of-charge (50% Li content) and an over-charged state (25% Li content). A systematic study using a suite of advanced synchrotron radiation characterization tools reveals the dynamics of thermal behavior of the charged NMC-811, which involves sophisticated structural and chemical evolution; e.g. lattice phase transformation, transition metal (TM) cation migration and valence change, and lithium redistribution. These intertwined processes exhibit a complex 3D spatial heterogeneity and, collectively, form a valence state gradient throughout the particles. Our study sheds light on the response of NMC-811 to elevated temperature and highlights the importance of the cathode's thermal robustness for battery performance and safety

AGO2: A New Argonaute Compromising Plant Virus Accumulation

Plant viruses use several strategies to transport their nucleic acid genomes throughout the plants. Regardless of the movement mechanism, a universal major block to uninterrupted viral trafficking is the induction of antiviral silencing that degrades viral RNA. To counteract this defense, viruses encode suppressors that block certain steps in the RNA silencing pathway, and consequently these proteins allow viral spread to proceed. There is a constant battle between plants and viruses and sometimes viruses will succeed and invade the plants and in other cases the RNA silencing mechanism will override the virus. A key role in the silencing versus suppression conflict between plants and viruses is played by one or more members of the Argonaute protein (AGO) family encoded by plants. Here we review the mechanisms and effects of antiviral silencing with an emphasis on the contribution of AGOs, especially the recently discovered role of AGO2

Efecto del perifiton fijado a substratos artificiales sobre la producción de Penaeus vannamei en cultivo semi-intensivo

En el cultivo de peneidos, la alimentación balanceada representa el mayor costo de producción, este puede variar entre 28% y 50%, y parte de la inversión en estas dietas artificiales puede ser perdida debido a una inadecuada formulación o debido a la baja asimilación. Las partículas de alimento no ingerido y/o no asimilado producen un exceso de materia orgánica que al degradarse forman compuestos como amonio, fosfatos, sulfuros, ácidos orgánicos que generan efluentes excesivamente cargados de nutrientes los cuales causan la eutrofización de las aguas receptoras. En contraste, varios estudios han indicado que los organismos de la productividad acuática natural son de gran valor alimenticio y nutritivo para las especies en cultivo, especialmente para los del género Penaeus por sus hábitos alimenticios, esto podría reducir significativamente los costos de producción y los riesgos de contaminación del agua debido al uso inadecuado de dietas artificiales

Determining the activity of 241Pu by liquid scintillation counting

Liquid scintillation counting (LSC) is one of the most widely used methods for determining the activity of 241Pu. One of the main challenges of this counting method is the efficiency calibration of the system for the low beta energies of 241Pu (E max=20.8 keV). In this paper we compare the two most frequently used methods, the CIEMAT/NIST efficiency tracing (CNET) method and the experimental quench correction curve method. Both methods proved to be reliable, and agree within their uncertainties, for the expected quenching conditions of the source

Aportación a la Geografía Social de España: las diferencias regionales del empleo asalariado.

Sin resume

Heroyda ouidiana : Dido a Eneas : con parafrasis española y morales reparos ilustrada

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-2010Sign.: [ ]4, a4, e2, A-Z4, 2A-2T4, 2V2Port. con viñeta xilViñetas xil. en p. 12 y p. 33

Fabricación de quesos nacionales : memoria premiada en el concurso celebrado en 1926

Precede al tít.: Asociación General de Ganaderos del Reino.Información tomada de la cub