72 research outputs found

    Emission-aware Energy Storage Scheduling for a Greener Grid

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    Reducing our reliance on carbon-intensive energy sources is vital for reducing the carbon footprint of the electric grid. Although the grid is seeing increasing deployments of clean, renewable sources of energy, a significant portion of the grid demand is still met using traditional carbon-intensive energy sources. In this paper, we study the problem of using energy storage deployed in the grid to reduce the grid's carbon emissions. While energy storage has previously been used for grid optimizations such as peak shaving and smoothing intermittent sources, our insight is to use distributed storage to enable utilities to reduce their reliance on their less efficient and most carbon-intensive power plants and thereby reduce their overall emission footprint. We formulate the problem of emission-aware scheduling of distributed energy storage as an optimization problem, and use a robust optimization approach that is well-suited for handling the uncertainty in load predictions, especially in the presence of intermittent renewables such as solar and wind. We evaluate our approach using a state of the art neural network load forecasting technique and real load traces from a distribution grid with 1,341 homes. Our results show a reduction of >0.5 million kg in annual carbon emissions -- equivalent to a drop of 23.3% in our electric grid emissions.Comment: 11 pages, 7 figure, This paper will appear in the Proceedings of the ACM International Conference on Future Energy Systems (e-Energy 20) June 2020, Australi

    Targeted epigenome editing of an endogenouslocus with chromatin modifiers is not stably maintained

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    Background: DNA methylation and histone 3 lysine 9 (H3K9) methylation are considered as epigenetic marks that can be inherited through cell divisions. To explore the functional consequences and stability of these modifications, we employed targeted installment of DNA methylation and H3K9 methylation in the vascular endothelial growth factor A (VEGF-A) promoter using catalytic domains of DNA or H3K9 methyltransferases that are fused to a zinc finger protein which binds a site in the VEGF-A promoter. Results: Expression of the targeted DNA and H3K9 methyltransferases caused dense deposition of DNA methylation or H3K9 di- and trimethylation in the promoter of VEGF-A and downregulation of VEGF-A gene expression. We did not observe positive feedback between DNA methylation and H3K9 methylation. Upon loss of the targeted methyltransferases from the cells, the epigenetic marks, chromatin environment, and gene expression Levels returned to their original state, indicating that both methylation marks were not stably propagated after their installment. Conclusions: The clear anti-correlation between DNA or H3K9 methylation and gene expression suggests a direct role of these marks in transcriptional control. The lack of maintenance of the transiently induced silenced chromatin state suggests that the stability of epigenetic signaling is based on an epigenetic network consisting of several molecular marks. Therefore, for stable reprogramming, either multivalent deposition of functionally related epigenetic marks or longer-lasting trigger stimuli might be necessary

    Abrasive water jet drilling of advanced sustainable bio-fibre-reinforced polymer/hybrid composites : a comprehensive analysis of machining-induced damage responses

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    This paper aims at investigating the effects of variable traverse speeds on machining-induced damage of fibre-reinforced composites, using the abrasive water jet (AWJ) drilling. Three different types of epoxy-based composites laminates fabricated by vacuum bagging technique containing unidirectional (UD) flax, hybrid carbon-flax and carbon fibre-reinforced composite were used. The drilling parameters used were traverse speeds of 20, 40, 60 and 80 mm/min, constant water jet pressure of 300 MPa and a hole diameter of 10 mm. The results obtained depict that the traverse speed had a significant effect with respect to both surface roughness and delamination drilling-induced damage responses. Evidently, an increase in water jet traverse speed caused an increase in both damage responses of the three samples. Significantly, the CFRP composite sample recorded the lowest surface roughness damage response, followed by C-FFRP, while FFRP exhibited the highest. However, samples of FFRP and hybrid C-FFRP recorded lowest and highest delamination damage responses, respectively. The discrepancy in both damage responses, as further validated with micrographs of colour video microscopy (CVM), scanning electron microscopy (SEM) and X-ray micro-computed tomography (X-ray μCT), is attributed to the different mechanical properties of the reinforced fibres, fibre orientation/ply stacking and hybridisation of the samples.Peer reviewe

    Rewriting DNA Methylation Signatures at Will:The Curable Genome Within Reach?

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    DNA methyltransferases are important enzymes in a broad range of organisms. Dysfunction of DNA methyltransferases in humans leads to many severe diseases, including cancer. This book focuses on the biochemical properties of these enzymes, describing their structures and mechanisms in bacteria, humans and other species, including plants, and also explains the biological processes of reading of DNA methylation and DNA demethylation. It covers many emerging aspects of the biological roles of DNA methylation functioning as an essential epigenetic mark and describes the role of DNA methylation in diseases. Moreover, the book explains modern technologies, like targeted rewriting of DNA methylation by designed DNA methyltransferases, as well as technological applications of DNA methyltransferases in DNA labelling. Finally, the book summarizes recent methods for the analysis of DNA methylation in human DNA. Overall, this book represents a comprehensive state-of-the-art- work and is a must-have for advanced researchers in the field of DNA methylation and epigenetics

    Analysing power consumption distribution in transparent optical networks

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    European Conference on Optical Communication, ECOC-85MO

    Formation of skin-core in carbon fibre processing: A defect or an effect?

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    The influence of stabilized fibre structure and skin-core formation induced by rapid thermal stabilization of polyacrylonitrile (PAN) on the tensile properties of carbon fibres was investigated. Three sets of samples were prepared by stabilizing PAN fibres under three temperature profiles using a continuous carbon fibre processing line. Initially, the chemical structure and density variations in stabilized fibres were examined with respect to process conditions using Fourier Transform Infrared Spectroscopy (FTIR) and density column methods. Interestingly, while the cyclization and dehydrogenation indices are similar for all the stabilized fibres irrespective of temperature profiles used, the densities of these fibres varied from 1.34 to 1.366 g/cc. Micro-Raman studies showed the existence of structural heterogeneity in the fibres from low temperature (LT) carbonization (I(D)/I(G) ratio of core was ~5.6% higher than the skin) that eventually reduced with high temperature (HT) carbonization because of uniform sp3 to sp2 hybridization of carbons. However, modulus mapping revealed heterogeneous storage modulus distribution in the HT carbon fibre cross-section from Trial-2 (storage modulus of core was ~23 GPa less than the skin). Interestingly, this heterogeneity did not show a significant effect on the bulk properties of carbon fibres suggesting skin-core formation is an effect rather than a defect

    Constructive Interconnection and Damping Assignment for Port-Controlled Hamiltonian Systems

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    The Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) problem for port-controlled Hamiltonian systems is revisited. We propose a methodology that exploits the novel notion of algebraic solution of the so-called matching equation. This notion is instrumental for the construction of an energy function, defined on an extended state-space, which does not rely upon the solution of any partial differential equation. This yields, differently from the classical solution, a dynamic state feedback that stabilizes a desired equilibrium point. In addition, conditions that allow to preserve the port-controlled Hamiltonian structure in the extended closed-loop system are provided. The theory is validated on two physical systems: the magnetic levitated ball and a third order food-chain system. A dynamic control law is constructed for both these systems by assigning a damping factor that cannot be assigned by the classical IDA-PBC

    Constructive interconnection and Damping Assignment for port-controlled Hamiltonian

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    The Interconnection and Damping Assignment passivity-based control method for port-controlled Hamiltonian systems is discussed. We propose a novel construction which exploits the notion of algebraic solution of the so-called matching equation. The latter notion is instrumental in constructing an energy function defined on an extended state-space without involving the solution of any partial differential equation. This results, differently from the classical solution, in a dynamic state feedback that stabilizes a desired equilibrium point. Finally we show that, in the linear time-invariant case and under standard assumptions, the proposed methodology provides the standard passivity-based controller. © 2013 AACC American Automatic Control Council
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