159 research outputs found

    Demand flexibility enabled by virtual energy storage to improve renewable energy penetration

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    The increasing resort to renewable energy distributed generation, which is needed to mitigate anthropogenic CO2 emissions, leads to challenges concerning the proper operation of electric distribution systems. As a result of the intrinsic nature of Renewable Energy Sources (RESs), this generation shows a high volatility and a low predictability that make the balancing of energy production and consumption difficult. At the same time, the electrification of new energy‐intensive sectors (such as heating) is expected. This complex scenario paves the way for new sources of flexibility that will have more and more relevance in the coming years. This paper analyses how the electrification of the heating system, combined with an electric flexibility utilisation module, can be used to mitigate the problems related to the fluctuating production of RES. By using Power‐to‐Heat (P2H) technologies, buildings are able to store the overproduction of RES in the form of thermal energy for end‐use according to the principle of the so‐called Virtual Energy Storage (VES). A context‐aware demand flexibility extraction based on the VES model and the flexibility upscale and utilisation on district‐level through grid simulation and energy flow optimisation is presented in the paper. The involved modules have been developed within the PLANET (PLAnning and operational tools for optimising energy flows and synergies between energy NETworks) H2020 European project and interact under a unified co‐simulation framework with the PLANET Decision Support System (DSS) for the analysis of multi‐energy scenarios. DSS has been used to simulate a realistic future energy scenario, according to which the imbalance problems triggered by RES overproduction are mitigated with the optimal exploitation of the demand flexibility enabled by VES

    A Combined First Principles and Kinetic Monte Carlo study of Polyoxometalate based Molecular Memory Devices

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    In this paper, we combine Density Functional Theory with Kinetic Monte Carlo methodology to study the fundamental transport properties of a type of polyoxometalate (POM) and its behaviour in a potential flash memory device. DFT simulations on POM molecular junctions helps us demonstrate the link between underlying electronic structure of the molecule and its transport properties. Furthermore, we show how various electrode-molecule contact configurations determine the electron transport through the POM. Also, our work reveals that the orientation of the molecule to the electrodes plays a key role in the transport properties of the junction. With Kinetic Monte Carlo we extend this investigation by simulating the retention time of a POM-based flash memory device. Our results show that a POM based flash memory could potentially show multi-bit storage and retain charge for up to 10 years

    Recent Advances on the Innate Immune Response to Coxiella burnetii.

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    Coxiella burnetii is an obligate intracellular Gram-negative bacterium and the causative agent of a worldwide zoonosis known as Q fever. The pathogen invades monocytes and macrophages, replicating within acidic phagolysosomes and evading host defenses through different immune evasion strategies that are mainly associated with the structure of its lipopolysaccharide. The main transmission routes are aerosols and ingestion of fomites from infected animals. The innate immune system provides the first host defense against the microorganism, and it is crucial to direct the infection towards a self-limiting respiratory disease or the chronic form. This review reports the advances in understanding the mechanisms of innate immunity acting during C. burnetii infection and the strategies that pathogen put in place to infect the host cells and to modify the expression of specific host cell genes in order to subvert cellular processes. The mechanisms through which different cell types with different genetic backgrounds are differently susceptible to C. burnetii intracellular growth are discussed. The subsets of cytokines induced following C. burnetii infection as well as the pathogen influence on an inflammasome-mediated response are also described. Finally, we discuss the use of animal experimental systems for studying the innate immune response against C. burnetii and discovering novel methods for prevention and treatment of disease in humans and livestock

    Graphene Photonics and Optoelectronics

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    The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential to be in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultra-wide-band tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light emitting devices, to touch screens, photodetectors and ultrafast lasers. Here we review the state of the art in this emerging field.Comment: Review Nature Photonics, in pres

    Functionalisation of PLLA nanofiber scaffolds using a possible cooperative effect between collagen type I and BMP-2: impact on growth and osteogenic differentiation of human mesenchymal stem cells

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    Mesenchymal stem cell differentiation of osteoblasts is triggered by a series of signaling processes including integrin and bone morphogenetic protein (BMP), which therefore act in a cooperative manner. The aim of this study was to analyze whether these processes can be remodeled in an artificial poly-(l)-lactide acid (PLLA) based nanofiber scaffold. Matrices composed of PLLA-collagen type I or BMP-2 incorporated PLLA-collagen type I were seeded with human mesenchymal stem cells (hMSC) and cultivated over a period of 22 days, either under growth or osteoinductive conditions. During the course of culture, gene expression of alkaline phosphatase (ALP), osteocalcin (OC) and collagen I (COL-I) as well as Smad5 and focal adhesion kinase (FAK), two signal transduction molecules involved in BMP-2 or integrin signaling were analyzed. Furthermore, calcium and collagen I deposition, as well as cell densities and proliferation, were determined using fluorescence microscopy. The incorporation of BMP-2 into PLLA-collagen type I nanofibers resulted in a decrease in diameter as well as pore sizes of the scaffold. Mesenchymal stem cells showed better adherence and a reduced proliferation on BMP-containing scaffolds. This was accompanied by an increase in gene expression of ALP, OC and COL-I. Furthermore the presence of BMP-2 resulted in an upregulation of FAK, while collagen had an impact on the gene expression of Smad5. Therefore these different strategies can be combined in order to enhance the osteoblast differentiation of hMSC on PLLA based nanofiber scaffold. By doing this, different signal transduction pathways seem to be up regulated

    Chickpea

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    The narrow genetic base of cultivated chickpea warrants systematic collection, documentation and evaluation of chickpea germplasm and particularly wild Cicer species for effective and efficient use in chickpea breeding programmes. Limiting factors to crop production, possible solutions and ways to overcome them, importance of wild relatives and barriers to alien gene introgression and strategies to overcome them and traits for base broadening have been discussed. It has been clearly demonstrated that resistance to major biotic and abiotic stresses can be successfully introgressed from the primary gene pool comprising progenitor species. However, many desirable traits including high degree of resistance to multiple stresses that are present in the species belonging to secondary and tertiary gene pools can also be introgressed by using special techniques to overcome pre- and post-fertilization barriers. Besides resistance to various biotic and abiotic stresses, the yield QTLs have also been introgressed from wild Cicer species to cultivated varieties. Status and importance of molecular markers, genome mapping and genomic tools for chickpea improvement are elaborated. Because of major genes for various biotic and abiotic stresses, the transfer of agronomically important traits into elite cultivars has been made easy and practical through marker-assisted selection and marker-assisted backcross. The usefulness of molecular markers such as SSR and SNP for the construction of high-density genetic maps of chickpea and for the identification of genes/QTLs for stress resistance, quality and yield contributing traits has also been discussed

    Erratum to: Retrosynthetic Analysis

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