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Hydrothermal synthesis is a chemical process that has gained much interest in recent years, especially for the synthesis of LiFePO4since it is a method that requires a relatively low temperature, short reaction time, and it is reproducible. In this work, LiFePO4microparticles have been synthesized by means of a fast heating system (sand bath) under hydrothermal conditions. The experiments have been carried out under two different heating rates (86 °C/min and 5.26 °C/min), two different residence times (5 and 30 min), and two different cooling rates (−455 °C/min and −8 °C/min). The effects that these three parameters had on the synthesized particles were verified using several techniques such as X-ray diffraction and scanning electron microscopy. It was observed that the heating rate had a great influence on the purity, crystallization, and morphology of the synthesized LiFePO4particles. In addition, the high influence of cooling rate on the crystallization and morphology of the particles was also analyzed.

This paper introduces the Electricity Generation Emissions (EGE) tracker as a new indicator for measuring the decarbonization process associated with the electricity generation mix. The EGE is a composite indicator calculated at the cross-country level on the basis of electricity production of different generation technologies weighted by their corresponding life cycle emission factors. In addition, a four-step methodology is proposed to monitor the energy transition rigorously. It combines index construction and decomposition with the application of machine learning and visualization techniques in a cross-country cluster analysis and temporal mapping. EGE tracker provides a benchmark for comparing countries' sustainability performance in the electricity generation process and quantifies the effectiveness of their climate policies. The design of the index offers a novel measurement to analyze the contribution of each technology to emission reduction.

The magnetic field line structure in a tokamak can be obtained by direct numerical integration of the field line equations. However, this is a lengthy procedure and the analysis of the solution may be very time-consuming. Otherwise we can use simple two-dimensional, area-preserving maps, obtained either by approximations of the magnetic field line equations, or from dynamical considerations. These maps can be quickly iterated, furnishing solutions that mirror the ones obtained from direct numerical integration, and which are useful when long-term studies of field line behavior are necessary (e.g. in diffusion calculations). In this work we focus on a set of simple tokamak maps for which these advantages are specially pronounced.

Abstract: The magnetic field line structure in a tokamak can be obtained by direct numerical integration of the field line equations. However, this is a lengthy procedure and the analysis of the solution may be very time-consuming. Otherwise we can use simple two-dimensional, area-preserving maps, obtained either by approximations of the magnetic field line equations, or from dynamical considerations. These maps can be quickly iterated, furnishing solutions that mirror the ones obtained from direct numerical integration, and which are useful when long-term studies of field line behavior are necessary (e.g. in diffusion calculations). In this work we focus on a set of simple tokamak maps for which these advantages are specially pronounced.

The magnetic field line structure in a tokamak can be obtained by direct numerical integration of the field line equations. However, this is a lengthy procedure and the analysis of the solution may be very time-consuming. Otherwise we can use simple two-dimensional, area-preserving maps, obtained either by approximations of the magnetic field line equations, or from dynamical considerations. These maps can be quickly iterated, furnishing solutions that mirror the ones obtained from direct numerical integration, and which are useful when long-term studies of field line behavior are necessary (e.g. in diffusion calculations). In this work we focus on a set of simple tokamak maps for which these advantages are specially pronounced.

The supercritical wet air oxidation of olive oil mill wastewater has been carried out at 25.0 MPa of total pressure and temperatures in the range 380−500 °C. The process is well described by simple first-order kinetics with no dependence on the oxygen concentration when it is in excess. The apparent activation energy of the reaction has been found to have a value of 32.7 kJ mol^-1 for chemical oxygen demand (COD) removal. Similar values have been calculated for other global parameters analyzed (total carbon, total organic carbon, etc.). The use of free-radical promoters enhances the efficiency of the treatment by lowering the activation energy of the process up to a value of 27.5 kJ mol^-1 for COD elimination. Both promoted and nonpromoted oxidations mainly occur through total mineralization.

Hydrothermal reactions (oxidation and hydrolysis) involving lactic acid (LA) were studied at temperatures ranging from 300 to 400 °C and a nominal pressure of 27.6 MPa. Kinetic models were developed with respect to concentrations of LA and total organic carbon (TOC), respectively. The best-fit model for LA oxidation with 95% confidence limits is −d[LA]/dt = 10^18.7±4.2 × exp(−226 ± 46.6 kJ/mol/RT)[LA]^0.88±0.11[O2]^0.16±0.19. Similarly, the best-fit TOC model for lactic acid oxidation is −d[TOC]/dt = 10^4.3±2.5 exp(−68.4 ± 27.2 kJ/mol/RT)[TOC]^0.62±0.33[O2]^0.36±0.26. The best-fit TOC model for lactic acid hydrolysis is −d[TOC]/dt = 10^8.4±2.1 exp(−125 ± 26.7 kJ/mol/RT)[TOC]. On the basis of identified liquid and gaseous products, pathways for hydrothermal reactions involving lactic acid were proposed. Acetic acid and acetaldehyde were confirmed as the major liquid intermediates for oxidation and hydrolysis reactions, respectively. Carbon monoxide and methane were identified as the major gaseous byproducts from these reactions. These results demonstrated the potential of completely oxidizing, as well as converting, lactic acid into other organic products, in high-temperature water.