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Abstract With drastic fossil fuel depletion and environmental deterioration concerns, a move towards a more sustainable bioenergy-based economy is essential. Lately, the application of microwave (MW) irradiation for waste processing has been attracting interest globally. MW-assisted heating possesses several advantages such as the provision of high microwave energy into dielectric materials with deeper penetration for internal heat generation, showing beneficial features in improving the heating rate and reducing the reaction time. Consequently, the most recent literature regarding the applications of MW-assisted heating for biomass pretreatment as well as biofuel and bioenergy production was reviewed and consolidated in this study. An impressive increase in the product yield and improvement of the product properties are reported, with the use of MW-assisted heating in several conversion routes to produce biofuels. Despite being a promising technology for biofuel production, some major fundamental data of MW-assisted heating have not been comprehensively identified. Therefore, the feasibility of this technology for large-scale implementation is still subpar. Understanding the interaction between the feedstock and the microwave electromagnetic field, and the optimization of several operational and mechanical parameters are the two main keystones that would propel the industrialization of MW heating in the near future. This provides key insights leading to increased feasibility and more advanced application of MW heating.

Climaps.eu is an online atlas providing data, visualizations and commentaries about climate adaptation debate. It contains 33 issue-maps and 5 issue-stories. Each of the maps focuses on one issue in the adaptation debate and provides.The atlas is addressed to climate experts (negotiators, NGOs and companies concerned by global warming, journalists…) and to citizens willing to engage with the issues of climate adaptation.It employs advanced digital methods to deploy the complexity of the issues related to climate adaptation and information design to make this complexity legible.

The present paper exhibits a real time assessment of a robust Energy Management Strategy (EMS) for battery-super capacitor (SC) Hybrid Energy Storage System (HESS). The proposed algorithm, dedicated to an electric vehicular application, is based on a self-gain scheduled controller, which guarantees the H∞ performance for a class of linear parameter varying (LPV) systems. Assuming that the duty cycle of the involved DC-DC converters are considered as the variable parameters, that can be captured in real time, and forwarded to the controller to ensure both; the performance and robustness of the closed-loop system. The subsequent controller is therefore time-varying and it is automatically scheduled according to each parameter variation. This algorithm has been validated through experimental results provided by a tailor-made test bench including both the HESS and the vehicle traction emulation system. The experimental results demonstrate the overall stability of the system, where the proposed LPV supervisor successfully accomplishes a power frequency splitting in an adequate way, respecting the dynamic of the sources. The proposed solution provides significant performances for different speed levels.

In the anodisation of Nb in acidic fluoride solutions or warm aqueous alkali, and in that of Mo in concentrated phosphoric acid, impedance spectroscopy provides evidence that 3D film growth proceeds already during the active–passive transition. Indeed, linear potential dependences of both the inverse of the high-frequency capacitance and of the product of the high-frequency resistance times the steady-state current are observed already below the peak potential. Simultaneously, a pseudo-inductive loop at intermediate frequencies is detected in the impedance spectra. In the present paper, we propose a kinetic model for the interpretation of these data. The model assumes that the metal is covered with a non-stoichiometric oxide containing at least two oxidation states of the cation. The processes of oxidative dissolution of the lower valence cations and their transformation to cations of higher valence, leading to passivation, explain the shape of the I–E curve. These processes are limited by both charge transfer at the film–solution (F/S) interface and transport of cation vacancies through the film. Thickening of the oxide film is assumed to proceed simultaneously, and is limited by transport of oxygen vacancies accelerated by an interfacial charge of cation vacancies.

Artículos en revistas Large frequency deviations due to a number of disturbances are frequent in small isolated power systems. The maximum frequency deviation in the system is limited to prevent other generator tripping. It is important to have an accurate model to calculate it, both for system planning and operation. A new simplified model to calculate the maximum frequency deviation when either a generator or load-related disturbance occurs in these systems is presented. This model takes into account the response of governor- prime mover even when different technologies are present in the power system. Model parameters can be easily obtained from either more complex models or from test records. Simulation results for an actual power system aimed at checking the model accuracy are presented. High accuracy is obtained while computation time is reduced due to the simplicity of the model. info:eu-repo/semantics/publishedVersion

When biomass is thermally treated, the enrichment of carbon in the remaining “green coal” is correlated with the temperature and duration. Other properties related to the energetic properties of the torrefied biomass are closely related to chemical modifications and correlated to the material mass loss occurring during the thermal degradation. The possibility of using near infrared spectrometry has been investigated to predict the mass loss of Pinus sylvestris wood torrefied at temperatures ranging from 220°C to 300°C with durations varying from 1 minute to 10 hours. A first mass loss prediction model (NIR‐260) associated with the mean torrefaction temperature of 260°C was developed, and appeared suitable only for this temperature due to specific chemical reactions rate. A second model (NIRS‐All), using all available data was constructed and showed an accurate mass loss prediction, for both low (220°C) and high temperatures (300°C). The main differences between NIRS‐260 and NIRS‐All models are mainly attributed to the thermal modification of hemicelluloses and cellulose fractions occurred during the wood torrefaction. The results showed near infrared spectrometry combined with multivariate calibration modeling have potential utility in an industrial context as a standardized continuous method to figure out the mass loss of biomass during torrefaction by a rapid characterization. Novelty Statement The novelty concerns the use of the Near Infrared Spectrometry (NIRS) combined with multivariate calibration modeling as a standardized method for determining the mass loss biomass during torrefaction by a rapid and nondestructive characterization. A model was constructed and showed an accurate mass loss prediction, for both low (220°C) and high temperatures (300°C). Near infrared spectrometry have potential utility in an industrial context as a standardized continuous method.

Abstract The main goal of the present work is to provide a mathematical model of Dye-Sensitized Solar Cells (DSCs) that can be implemented in electrical engineering circuit simulation software, such as PSIM, for using in electronic power converter design. Consequently, a new circuit modeling approach is presented, able to solve the standard continuity and transport governing equations defined for the involved mobile species: electrons in the TiO2 conduction band and ions in the electrolyte. Starting from the partial differential continuity equations of the phenomenological DSC model, it was developed a one-dimensional spatial discretization using Finite Difference Methods (FD) followed by a solution using an electrical circuit analogy. The resulting circuits were then implemented in PSIM software and simulated. Simulation results using this new electrical analog approach showed excellent matching when compared to FORTRAN numerical solutions, as well as when compared to experimental data. Moreover, the electrical analog can be used for transient and steady state cases, giving information about the main factors and the relevant kinetic parameters that influence DSCs’ performance. Finally, it enables to relate the phenomenological behavior with other electrical approaches, such as Electrochemical Impedance Spectroscopy (EIS) and diode based models.

SUMMARYWe demonstrated experimentally that coconut husk ash is an excellent mineral fertilizer for immature coconut hybrids on developed peat, providing potassium (K) in particular. Coconut husk ash performed as well as potassium chloride (KCl) in a proportion of 2–2.5 to 1. At four years, 99% of coconut palms fertilized with husk ash, 92% of coconut palms fertilized with KCl and 26% of control palms were sexually differentiated. The cumulative yield in the first two harvesting years more than trebled between control palms (26 nuts per tree) and the palms fertilized with KCl (93 nuts per tree) or husk ash (105 nuts per tree). This is an important result, given the intensity of K deficiency and the increasing cost of imported fertilizers. Although coconut husk ash will never totally replace K fertilizer, it can recycle a substantial proportion of nutrients in a coconut plantation. It now remains to optimize its use on an estate level, by examining the feasibility and cost-effectiveness of its mass production and determining conditions for maximum efficiency.