Dispatchable High-Power Wind Turbine Based on a Multilevel Converter with Modular Structure and Hybrid Energy Storage Integration

This paper presents a new multilevel converter solution with modular structure and hybrid energy-storage integration suitable to drive modern/future high-power medium-voltage wind turbines. The hybrid energy-storage integration means that part of the converter submodules are built with batteries and part of them with conventional capacitors. Since traditional wind turbines are non-dispatchable generators, the integration of an energy storage system could be beneficial in multiple ways as the wind power plant could provide stability support to the grid, improvement of the unit commitment and economic dispatch, and the power plant owner could increase his revenues in the electricity market. The capacitors of the proposed converter are responsible to transfer the power produced by the wind turbine to the grid, and the batteries are only charged/discharged with the mismatch between the power produced by the turbine and the power to be injected into the grid, considering a dispatchable operation where the power injected into the grid is different from the power generated by the turbine. The medium-voltage structure could be an interesting option to overcome problems related to high currents in modern/future high-power wind turbines resulting in more efficient, more compact and lighter solutions. Modular multilevel converters are suitable to handle medium-voltage levels and they allow for a straightforward integration of energy storage systems in a decentralized manner

Interfaz JAUS para herramientas de desarrollo en el campo de la robótica

Software modularization presents important advantages when it comes to robotic development. That is based on the definition of well-known limits for each module that make the parallel development easier. Furthermore, that way of working allows the reutilization of one module in more systems. There is a paradigm known as Components Based Software which follows the mentioned idea and needs definitions that include interfaces, responsibilities and certain communication rules between the members of the whole system. Precisely, the JAUS standard defines both a model of components with their interfaces, and an architecture, in the specific context of robotics. There are several SDKs, but they either lack a multi-platform support, or work with platforms whose features do not satisfy the needs of the developers, such as agile development of proof of concepts, robotic specific development resources (existent projects, community support, GUI, among others). This work extends the possibilities of the implementation of a component, and allows the developer to take advantage of the benefits of the chosen platform. As a result, projects based on widely used tools used in robotics (such as MATLAB, Simulink and LabVIEW) can be easily integrated in a short period of time.Presentado en el II Workshop Innovación en Sistemas de Software (WISS)Red de Universidades con Carreras en Informática (RedUNCI

Fast DNA translocation through a solid-state nanopore

We report translocation experiments on double-strand DNA through a silicon oxide nanopore. Samples containing DNA fragments with seven different lengths between 2000 to 96000 basepairs have been electrophoretically driven through a 10 nm pore. We find a power-law scaling of the translocation time versus length, with an exponent of 1.26 $\pm$ 0.07. This behavior is qualitatively different from the linear behavior observed in similar experiments performed with protein pores. We address the observed nonlinear scaling in a theoretical model that describes experiments where hydrodynamic drag on the section of the polymer outside the pore is the dominant force counteracting the driving. We show that this is the case in our experiments and derive a power-law scaling with an exponent of 1.18, in excellent agreement with our data.Comment: 5 pages, 2 figures. Submitted to PR

Interfaz JAUS para herramientas de desarrollo en el campo de la robótica

Software modularization presents important advantages when it comes to robotic development. That is based on the definition of well-known limits for each module that make the parallel development easier. Furthermore, that way of working allows the reutilization of one module in more systems. There is a paradigm known as Components Based Software which follows the mentioned idea and needs definitions that include interfaces, responsibilities and certain communication rules between the members of the whole system. Precisely, the JAUS standard defines both a model of components with their interfaces, and an architecture, in the specific context of robotics. There are several SDKs, but they either lack a multi-platform support, or work with platforms whose features do not satisfy the needs of the developers, such as agile development of proof of concepts, robotic specific development resources (existent projects, community support, GUI, among others). This work extends the possibilities of the implementation of a component, and allows the developer to take advantage of the benefits of the chosen platform. As a result, projects based on widely used tools used in robotics (such as MATLAB, Simulink and LabVIEW) can be easily integrated in a short period of time.Presentado en el II Workshop Innovación en Sistemas de Software (WISS)Red de Universidades con Carreras en Informática (RedUNCI

Propuesta Educativa Basada en Proyectos Prácticos de Robótica Avanzada sobre Plataforma Jetson TX1 para Estudiantes de Grado y Posgrado

En este trabajo se describe una propuesta para un curso de robótica avanzada basado en proyectos prácticos e implementado sobre un ordenador embebido Nvidia Jetson Tegra X1 dirigido a estudiantes de grado avanzados o de posgrado. El programa utiliza sensores de última generación y computadoras integradas para la robótica móvil. Estos componentes son integra-dos a una plataforma de desarrollo móvil. El programa tiene tres rasgos distintivos destacados: (1) se centra en sistemas de soft¬ware de robótica: los estudiantes diseñan y construyen software de robótica hacia aplicaciones del mundo real, sin ser distraídos por problemas de hardware; (2) promueve el aprendizaje basado en proyectos: los estudiantes aprenden a través de asignaciones de proyectos semanales y un desafío final del curso; (3) el aprendizaje se implementa de manera colaborativa: los alumnos aprenden los conceptos básicos de colaboración y comunicación técnica en las conferencias y trabajan en equipo para diseñar e implementar sus sistemas de software. El programa se basa en el curso de robótica desarrollado por el Profesor John Seng y su equipo, en la Universidad politécnica estatal de California. También discutimos brevemente las direcciones y oportunidades futuras

Highly skewed T-cell receptor V-beta chain repertoire in the bone marrow is associated with response to immunosuppressive drug therapy in children with very severe aplastic anemia

One of the major obstacles of immunosuppressive therapy (IST) in children with severe aplastic anemia (SAA) comes from the often months-long unpredictability of bone-marrow (BM) recovery. In this prospective study in children with newly diagnosed very severe AA (n=10), who were enrolled in the therapy study SAA-BFM 94, we found a dramatically reduced diversity of both CD4+ and CD8+ BM cells, as scored by comprehensive V-beta chain T-cell receptor (TCR) analysis. Strongly skewed TCR V-beta pattern was highly predictive for good or at least partial treatment response (n=6, CD8+ complexity scoring median 35.5, range 24–73). In contrast, IST in patients with rather moderate reduction of TCR V-beta diversity (n=4, CD8+ complexity scoring median 109.5, range 82–124) always failed (P=0.0095). If confirmed in a larger series of patients, TCR V-beta repertoire in BM may help to assign children with SAA up-front either to IST or to allogeneic stem-cell transplantation

Effect of inclusion of MOF-polymer composite onto a carbon foam material for hydrogen storage application

Despite the extensive studies done on the remarkable characteristics of metal–organic frameworks (MOFs) for gas storage applications, several issues still preclude their widespread commercial lightweight applications. In most cases, MOF materials are produced in powdery form and often require shaping to attain application-specific properties. Fabrication of MOF-polymer composites is considered an attractive approach for shaping MOF powders. In most cases, the final hybrid material retains the intrinsic adsorbing properties of the pristine MOF coupled with other interesting synergistic features which are sometimes superior to their pristine counterparts. In this regard, the use of porous polymers of intrinsic microporosity (such as PIM-1) has proved to be of interest. However, most of these polymers lack some other important properties such as conductivity, which is of paramount importance in a hydrogen storage system. It is on this basis that our study aimed at direct anchoring of a PIM-1/MOF viscous solution onto a carbon foam (CF) substrate. The effects of PIM-1/UiO-66(Zr) inclusion into CF to the resulting thermal properties (thermal conductivity, thermal diffusivity and volumetric heat capacity) as well as hydrogen uptake capacity was investigated. Contrary to our expectations, the incorporation of PIM-1/UiO-66(Zr) into CF only offered better handling but did not lead to the enhancement of thermal conductivity.The Department of Science and Innovation (DSI) of South Africa towards HySA Infrastructure, National Research Foundation (NRF) for SA/France collaboration funding and the Royal Society—DFID Africa Capacity Building Initiative Programme Grant.http://link.springer.com/journal/109042021-08-09hj2020Chemistr

Polymer-based shaping strategy for zeolite templated carbons (ZTC) and their metal organic framework (MOF) composites for improved hydrogen storage properties

Porous materials such as metal organic frameworks (MOFs), zeolite templated carbons (ZTC), and some porous polymers have endeared the research community for their attractiveness for hydrogen (H2) storage applications. This is due to their remarkable properties, which among others include high surface areas, high porosity, tunability, high thermal, and chemical stability. However, despite their extraordinary properties, their lack of processability due to their inherent powdery nature presents a constraining factor for their full potential for applications in hydrogen storage systems. Additionally, the poor thermal conductivity in some of these materials also contributes to the limitations for their use in this type of application. Therefore, there is a need to develop strategies for producing functional porous composites that are easy-to-handle and with enhanced heat transfer properties while still retaining their high hydrogen adsorption capacities. Herein, we present a simple shaping approach for ZTCs and their MOFs composite using a polymer of intrinsic microporosity (PIM-1). The intrinsic characteristics of the individual porous materials are transferred to the resulting composites leading to improved processability without adversely altering their porous nature. The surface area and hydrogen uptake capacity for the obtained shaped composites were found to be within the range of 1,054–2,433 m2g−1 and 1.22–1.87 H2 wt. %, respectively at 1 bar and 77 K. In summary, the synergistic performance of the obtained materials is comparative to their powder counterparts with additional complementing properties.The Department of Science and Technology (DST) of South Africa toward HySA Infrastructure (Grant No. ENMH01X), National Research Foundation (NRF) for SA/France collaboration funding (Grant No. ENMH20X) and the Royal Society—DFID Africa Capacity Building Initiative Programme Grant (Grant No. AQ150029).http://www.frontiersin.org/Chemistryam2020Chemistr