This paper evaluates the option of using a new powertrain based on fuel cell (FC), battery and supercapacitor (SC) for the Urbos 3 tramway in Zaragoza, Spain. In the proposed powertrain ...configuration, a hydrogen Proton-Exchange-Membrane (PEM) FC acts as main energy source, and a Li-ion battery and a SC as energy support and storage systems. The battery supports the FC during the starting and accelerations, and furthermore, it absorbs the power generated during the regenerative braking. Otherwise, the SC, which presents the fastest dynamic response, acts mainly during power peaks, which are beyond the operating range of the FC and battery. The FC, battery and SC use a DC/DC converter to connect each energy source to the DC bus and to control the energy exchange. This configuration would allow the tramway to operate in an autonomous way without grid connection. The components of the hybrid tramway, selected from commercially available devices have been modeled in MATLAB-Simulink. The energy management system used for controlling the components of the new hybrid system allows optimizing the fuel consumption (hydrogen) by applying an equivalent consumption minimization strategy. This control system is evaluated by simulations for the real driving cycle of the tramway. The results show that the proposed control system is valid for its application to this hybrid system.
► This paper evaluates a new powertrain based on fuel cell, battery and supercapacitor. ► Supercapacitor presents the fastest dynamic response. ► A DC/DC converter is used to connect each energy source to the DC bus. ► The models have been designed from commercially available components. ► The proposed control system is valid for its application to this hybrid system.
•We present an energy management system for a stand-alone WT/PV/hydrogen/battery hybrid system.•Hierarchical control composed by master and slave control strategies.•Control assures reliable ...electricity support for stand-alone applications subject to technical and economic criteria.
This paper presents an energy management system (EMS) for stand-alone hybrid systems composed by photovoltaic (PV) solar panels and a wind turbine (WT) as primary energy sources and two energy storage systems, which are a hydrogen system and a battery. The hydrogen system is composed of fuel cell (FC), electrolyzer and hydrogen storage tank. The EMS is a hierarchical control composed by a master control strategy and a slave control strategy. On the one hand, the master control generates the reference powers to meet several premises (such as to satisfy the load power demand, and to maintain the hydrogen tank level and the state of charge (SOC) of the battery between their target margins), taking also into account economic aspects to discriminate between using the battery or hydrogen system. On the other hand, the slave control modifies the reference powers generated by the master control according to the energy sources dynamic limitations, and maintains the DC bus voltage at its reference value. The models, implemented in MATLAB-Simulink environment, have been developed from commercially available components. To check the viability of the proposed EMS, two kinds of simulations were carried out: (1) A long-term simulation of 25years (expected lifetime of the system) with a sample time of one hour to validate the master control of the EMS; and (2) A short-term simulation with sudden net power variations to validate the slave control of the EMS.
The Ensembl (http://www.ensembl.org/) project provides a comprehensive and integrated source of annotation of chordate genome sequences. Over the past year the number of genomes available from ...Ensembl has increased from 15 to 33, with the addition of sites for the mammalian genomes of elephant, rabbit, armadillo, tenrec, platypus, pig, cat, bush baby, common shrew, microbat and european hedgehog; the fish genomes of stickleback and medaka and the second example of the genomes of the sea squirt (Ciona savignyi) and the mosquito (Aedes aegypti). Some of the major features added during the year include the first complete gene sets for genomes with low-sequence coverage, the introduction of new strain variation data and the introduction of new orthology/paralog annotations based on gene trees.
Anaphylaxis has been defined as a ‘severe, life‐threatening generalized or systemic hypersensitivity reaction’. However, data indicate that the vast majority of food‐triggered anaphylactic reactions ...are not life‐threatening. Nonetheless, severe life‐threatening reactions do occur and are unpredictable. We discuss the concepts surrounding perceptions of severe, life‐threatening allergic reactions to food by different stakeholders, with particular reference to the inclusion of clinical severity as a factor in allergy and allergen risk management. We review the evidence regarding factors that might be used to identify those at most risk of severe allergic reactions to food, and the consequences of misinformation in this regard. For example, a significant proportion of food‐allergic children also have asthma, yet almost none will experience a fatal food‐allergic reaction; asthma is not, in itself, a strong predictor for fatal anaphylaxis. The relationship between dose of allergen exposure and symptom severity is unclear. While dose appears to be a risk factor in at least a subgroup of patients, studies report that individuals with prior anaphylaxis do not have a lower eliciting dose than those reporting previous mild reactions. It is therefore important to consider severity and sensitivity as separate factors, as a highly sensitive individual will not necessarily experience severe symptoms during an allergic reaction. We identify the knowledge gaps that need to be addressed to improve our ability to better identify those most at risk of severe food‐induced allergic reactions.
Summary
Background
The most commonly used second‐line Helicobacter pylori eradication regimens are bismuth‐containing quadruple therapy and levofloxacin‐containing triple therapy, both offering ...suboptimal results. Combining bismuth and levofloxacin may enhance the efficacy of rescue eradication regimens.
Aims
To evaluate the efficacy and tolerability of a second‐line quadruple regimen containing levofloxacin and bismuth in patients whose previous H. pylori eradication treatment failed.
Methods
This was a prospective multicenter study including patients in whom a standard triple therapy (PPI–clarithromycin–amoxicillin) or a non‐bismuth quadruple therapy (PPI–clarithromycin–amoxicillin–metronidazole, either sequential or concomitant) had failed. Esomeprazole (40 mg b.d.), amoxicillin (1 g b.d.), levofloxacin (500 mg o.d.) and bismuth (240 mg b.d.) was prescribed for 14 days. Eradication was confirmed by 13C‐urea breath test. Compliance was determined through questioning and recovery of empty medication envelopes. Incidence of adverse effects was evaluated by questionnaires.
Results
200 patients were included consecutively (mean age 47 years, 67% women, 13% ulcer). Previous failed therapy included: standard clarithromycin triple therapy (131 patients), sequential (32) and concomitant (37). A total of 96% took all medications correctly. Per‐protocol and intention‐to‐treat eradication rates were 91.1% (95%CI = 87–95%) and 90% (95%CI = 86–94%). Cure rates were similar regardless of previous (failed) treatment or country of origin. Adverse effects were reported in 46% of patients, most commonly nausea (17%) and diarrhoea (16%); 3% were intense but none was serious.
Conclusions
Fourteen‐day bismuth‐ and levofloxacin‐containing quadruple therapy is an effective (≥90% cure rate), simple and safe second‐line strategy in patients whose previous standard triple or non‐bismuth quadruple (sequential or concomitant) therapies have failed.
High concentration photovoltaic technology promises the large-scale generation of clean-renewable energy with competitive costs. Like any other systems for electricity generation, it is important to ...know the electrical characteristics of the system. However, while there is a wide experience in modeling the behavior of traditional photovoltaic systems, not every model for flat-plate solar cells or modules is directly applicable to high concentration photovoltaic cells or modules because of the special features of these devices (use of multijunction cells, use of optics for high concentration, etc.). So, in recent years, the scientific community has devoted considerable efforts in developing models that reproduce the electrical behavior of high concentration cells and modules. These models allow calculating the main electrical parameters of the device from its operating conditions (irradiance, cell temperature, spectral distribution of the radiation, etc.). In this paper, a comprehensive review of existing models for the electrical characterization of high concentration photovoltaic cells and modules is presented with the aim of helping the photovoltaic professionals and researchers in the design, monitoring and energy prediction tasks.
Abstract
The black hole (BH) binary V404 Cyg entered the outburst phase in 2015 June after 26 yr of X-ray quiescence, and with its behaviour broke the outburst evolution pattern typical of most BH ...binaries. We observed the entire outburst with the Swift satellite and performed time-resolved spectroscopy of its most active phase, obtaining over a thousand spectra with exposures from tens to hundreds of seconds. All the spectra can be fitted with an absorbed power-law model, which most of the time required the presence of a partial covering. A blueshifted iron-Kα line appears in 10 per cent of the spectra together with the signature of high column densities, and about 20 per cent of the spectra seem to show signatures of reflection. None of the spectra showed the unambiguous presence of soft disc–blackbody emission, while the observed bolometric flux exceeded the Eddington value in 3 per cent of the spectra. Our results can be explained assuming that the inner part of the accretion flow is inflated into a slim disc that both hides the innermost (and brightest) regions of the flow, and produces a cold, clumpy, high-density outflow that introduces the high absorption and fast spectral variability observed. We argue that the BH in V404 Cyg might have been accreting erratically or even continuously at Eddington/super-Eddington rates – thus sustaining a surrounding slim disc – while being partly or completely obscured by the inflated disc and its outflow. Hence, the largest flares produced by the source might not be accretion-driven events, but instead the effects of the unveiling of the extremely bright source hidden within the system.
Research into the development of renewable and sustainable fuels has been a major concern during last decades. Microalgae, as a potential resource, have gained great attention for energy purposes. In ...this context, anaerobic digestion seems to be the most direct energy generation process. Nevertheless, the efficiency of this process is hampered due to the hard cell wall of some microalgae. In order to enhance its anaerobic biodegradability, the present research investigated the effect of thermal pretreatment at two temperatures (70 and 90 °C) applied to Scenedesmus biomass. No differences were detected in terms of organic matter or ammonium release upon the two tested temperatures. Nevertheless, a different fact was observed for their anaerobic biodegradability. While raw and pretreated at 70 °C microalgae attained 22–24% anaerobic biodegradability, microalgae pretreated at 90 °C achieved anaerobic biodegradability of 48%. Even though similar profiles were obtained for both temperatures along the pretreatment period, the damage caused in the cell wall at 90 °C seemed to be greater and rendered this substrate readily degradable for anaerobic digestion.
► Efficiency of anaerobic digestion is hampered due to microalgae cell wall. ► Pretreatment temperature dependency was observed on Scenedesmus biomass. ► Sytox green dye is a helpful tool to identify cell wall disruption. ► Thermal pretreatment at 90 °C was successful for increasing methane production.
A search for the resonant production of high-mass photon pairs is presented. The analysis is based on samples of proton-proton collision data collected by the CMS experiment at center-of-mass ...energies of 8 and 13 TeV, corresponding to integrated luminosities of 19.7 and 3.3fb super(?1), respectively. The interpretation of the search results focuses on spin-0 and spin-2 resonances with masses between 0.5 and 4 TeV and with widths, relative to the mass, between 1.4x10 super(?4) and 5.6x10 super(?2). Limits are set on scalar resonances produced through gluon-gluon fusion, and on Randall-Sundrum gravitons. A modest excess of events compatible with a narrow resonance with a mass of about 750 GeV is observed. The local significance of the excess is approximately 3.4 standard deviations. The significance is reduced to 1.6 standard deviations once the effect of searching under multiple signal hypotheses is considered. More data are required to determine the origin of this excess.
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