El Blog como consuelo

Sección: Así somosEl Blog Kemixon Reporter 2.0 nació hace ya más de un año como una invitación de la Biblioteca CID a la mezcla y a la curiosidad: la idea era, por una parte, ser útiles para el trabajo de nuestros usuarios, ofreciéndoles instrumentos tanto de investigación como de análisis y, por otra, ser útiles para poner cara, color, discurso, poesía, imagen, desorden… y, en último caso, sentido, a todos los alrededores de las ciencias experimentales que estos usuarios practican.N

Design and implementation of the control of an MMC-based solid state transformer

Implementation of the control of a Solid State Transformer (SST) is described in this paper. The SST topology considered is derived from a Modular Multilevel Converter (MMC), in which the cells have the capability to transfer (inject or drain) power. The MMC is combined with an isolation stage formed by Dual Active Bridges (DABs) and a DC/AC power converter. The resulting modular multiport power converter can connect both high voltage and low voltage AC and DC ports, providing isolation between the high voltage and the low voltage terminals, and with full control of the power flow. Implementation of the control of this power converter is not trivial, due to the large amount of power devices and sensors involved, and to the complexity of the control algorithms. Furthermore, the need to provide isolation among the different stages adds further concerns mainly related with cost. This paper discusses the configuration, selection of the required hardware, as well as implementation aspects for the control of the proposed SST topolog

Changes in antimicrobial susceptibility of Actinobacillus pleuropneumoniae isolated from pigs in Spain during the last decade

5 p.A total of 229 Spanish Actinobacillus pleuropneumoniae isolates recovered from diseased pigs with pleuropneumonia from 1997 to 2004 was tested for their susceptibility to 11 antimicrobials in a broth microdilution method. All the isolates were susceptible to florfenicol andmost of themto cephalothin; however, a high rate of resistancewas observed to tetracycline.Abimodal or multimodal distribution of isolates over the MIC range were observed for penicillins, tetracycline, trimethoprim, sulfisoxazole and nalidixic acid, suggesting the development of acquired resistance. Eight resistance patterns were established, and 21.1%of the isolates were resistant to at least two antimicrobials. In addition, a considerable increase in the resistance to tetracyclines was observed during the last decade in Spain, when compared with other A. pleuropneumoniae strains isolated during 1987–1988S

Operation and control of MMCs using cells with power transfer capability

Cells in conventional Modular Multilevel Converters (MMC) designs use a capacitor for energy storage. This means that the net power balance for each cell (neglecting losses) needs to be equal to zero, the MCC realizing therefore a power transfer between its DC and AC sides. This paper analyzes the design, operation and control of MMCs in which the cells have the capability to transfer (inject or drain) power. The use of such cells opens several new functionalities and uses for the MMC. On one hand, it would allow integrating elements like distributed energy storage (e.g. batteries), low-voltage/low power sources (e.g. PV) and loads at the cell level. Cells with power transfer capability can also be used connect the medium/high voltage DC and AC ports intrinsic to the MMC, with low voltage DC/AC ports at the cell level. This would result in multiport power converters, potential applications of this topology including solid state transformers (SST

High-quality region-based foreground segmentation using a spatial grid of SVM classifiers

This paper presents a novel background modeling system that uses a spatial grid of Support Vector Machines classifiers for segmenting moving objects, which is a key step in many video-based consumer applications. The system is able to adapt to a large range of dynamic background situations since no parametric model or statistical distribution are assumed. This is achieved by using a different classifier per image region that learns the specific appearance of that scene region and its variations (illumination changes, dynamic backgrounds, etc.). The proposed system has been tested with a recent public database, outperforming other state-of-the-art algorithms

Control strategies for MMC using cells with power transfer capability

IEEE Energy Conversion Congress and Exposition, ECCE 2015 (2015. Montréal)Conventional MMCs use cells which typically consist of a half-bridge and a capacitor. Due to their limited energy storage capability, the net power balance of the cells is zero (neglecting losses), the MMC therefore realizing a bidirectional power transfer between its DC and AC ports. It is possible however to provide the MMC with the capability to transfer power at the cell level. The use of such cells opens new functionalities and uses for the MMC, including integration at the cell level of distributed energy storage (e.g. batteries), low-voltage/low power sources/loads, and its operation as a multiport power converter, combining high and low voltage AC and DC ports. Existing control strategies for MMCs assume that all the cells have an identical design and operate identically. However, use of cells with power transfer capability can result in imbalances in their operation, provided that not all the cells transfer power, or that they do not transfer the same amount of power. This paper addresses the design and control of MMCs using cells with power transfer capability, with special focus on the design of suitable control strategies and on the definition of their limits of operatio

Effects of palmitoylethanolamide in cocaine-induced behaviours

Aims. Cocaine addiction is a chronically relapsing disorder characterized by the compulsion to seek and take the drug. Previous investigations have demonstrated that several drugs of abuse, as cocaine, can alter the levels of lipid-based signalling molecules such as the N-acylethanolamines (NAEs). In addition, NAEs levels in the brain are sensitive to cocaine self-administration and extinction training. In this context, this study aimed to investigate the effect of repeated and acute palmitoylethanolamide (PEA), an endogenous NAE, on the behavioural effects of cocaine using mouse models of conditioned reward and psychomotor activation. Methods. Using male C57BL/6J mice, the ability of repeated PEA injections (1 or 10 mg/kg i.p) to modulate the development of a conditioned place preference (CPP) and behavioural sensitization (BS) induced by cocaine (20 mg/kg i.p.) was evaluated. In addition, the expression of cocaine-induced CPP and BS after acute PEA administration was also studied. Results. PEA (1 and 10 mg/kg i.p) significantly reduced the development of cocaine-induced BS, but did not modify the acquisition of cocaine-induced CPP. Furthermore, both doses of PEA were able to reduce the expression of BS and CPP. Conclusions. Altogether, these findings show that exogenous administration of PEA attenuated psychomotor activation and impaired the expression of CPP induced by cocaine. Our results may be relevant in order to understand the role of NAEs in the development and treatment of cocaine addiction.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. PSI2013-44901-P, AP2010-2044, FPU13/04819, CD12/0045

Energization and Start-up of Modular Three-stage Solid State Transformers

Workshop on Control and Modeling for Power Electronics, COMPEL (9th, 2028, Padua

Auxiliary power supply based on a modular ISOP Flyback configuration with very high input voltage

This paper proposes a Flyback-based Input-Series Output-Parallel (ISOP) Auxiliary Power Supply (APS), intended to feed the control system of the cells of a Solid-State Transformer (SST). The SST topology is based on a modular Multiport Multilevel Converter (MMC). Energization of the cells auxiliary circuitry is not trivial due to the high voltages involved (tens of kV for the electric power distribution system), most of the commercially available control and driving circuitry not being usable due to the isolation requirements. It is possible to energize the control circuitry from an APS, connected to the cell capacitor voltage. However, in the SST under consideration, cells target DC voltage is in the range of 1.5kV to 2.5kV. Design of an APS capable of feeding the auxiliary circuitry from such high voltage and the required isolation is not trivial. A modular APS using autonomous Flyback converters in Continuous Conduction Mode (CCM) and based on commercial AC adapters is proposed in this paper. The solution is scalable and therefore applicable to cells with larger DC voltage