257 research outputs found

    All UK electricity supplied by wind and photovoltaics – The 30–30 rule

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    Based on weather and electricity demand data for the period 1984–2013, we develop a system model based on energy balance to determine the size of photovoltaic and wind generation combined with energy storage to provide a firm power supply for Great Britain. A simple graphical methodology is proposed where the required wind and PV generation capacities can be read off from a “system configuration diagram” as a function of the available storage size. We show, by way of illustration, that a reliable supply would be produced by a system based on PV and wind generators generating some 30% more electrical energy (approximately 100TWh p.a.) than the current electricity supply system if supplemented with 30 days of storage. In terms of generation capacities, the current 82GW of principally thermal generation would then be replaced by about 150GW of wind turbines and 35GW of PV arrays

    Sunrise to sunset optimization of thin film antireflective coatings for encapsulated, planar silicon solar cells

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    We present an approach for the optimization of thin film antireflective coatings for encapsulated planar silicon solar cells in which the variations in the incident spectra and angle of incidence (AOI) over a typical day are fully considered. Both the angular and wavelength dependences of the reflectance from the surface, absorptance within the coating, and transmittance into the device are calculated for both single- and doublelayer antireflection coatings with and without thin silicon oxide passivation layers. These data are then combined with spectral data as a function of time of day and internal quantum efficiency to estimate the average short-circuit current produced by a fixed solar cell during a day. This is then used as a figure of merit for the optimization of antireflective layer thicknesses for modules placed horizontally at the equator and on a roof in the UK. Our results indicate that only modest gains in average short-circuit current could be obtained by optimizing structures for sunrise to sunset irradiance rather than AM15 at normal incidence, and fabrication tolerances and uniformities are likely to be more significant. However, we believe that this overall approach to optimization will be of increasing significance for new, potentially asymmetric, antireflection schemes such as those based on subwavelength texturing or other photonic or plasmonic technologies currently under development especially when considered in combination with modules fixed at locations and directions that result in asymmetric spectral conditions

    Early Growth and Development Impairments in Patients with Ganglioside GM3 Synthase Deficiency

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    Ganglioside GM3 synthase is a key enzyme involved in the biosynthesis of gangliosides. GM3 synthase deficiency (GSD) causes a complete absence of GM3 and all downstream biosynthetic derivatives. The individuals affected by this disorder manifest severe irritability, intractable seizures and profound intellectual disability. However, we have found that most newborns seem symptom-free for a period of time after birth. In order to further understand the onset of the disease, we investigated the early growth and development of patients with this condition through this study. We compared 37 affected individuals with their normal siblings and revealed that all children with GSD had relatively normal intrauterine growth and development, as their weight, length and head circumference were similar to their normal siblings at birth. However, the disease progresses quickly after birth and causes significant constitutional impairments of growth and development by 6 months of age. Neither breastfeeding nor gastrostomy tube placement made significant difference on growth and development as all groups of patients showed the similar pattern. We conclude that GSD causes significant postnatal growth and developmental impairments and the amount of gangliosides in breast milk and general nutritional intervention do not seem to alter these outcomes

    Exploring the meaning and productivity of a polysemous prefix

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    This paper follows a corpus-based approach to the meaning and productivity of the Modern Greek prepositional prefix para-. A semantic categorization of the prefix is proposed and its productivity is measured across semantic categories, registers, text types and grammatical categories. Para- was found to be more productive in non-locational and evaluative meanings. Its most productive meaning is excess, while the locational meaning of proximity still remains strong. It is also more productive in written than spoken registers and the grammatical category of nouns. The findings of the study can have implications about the prefix’s ongoing grammaticalization and its affixal status

    A novel CISD2 mutation associated with a classical Wolfram syndrome phenotype alters Ca2+ homeostasis and ER-mitochondria interactions.

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    Wolfram syndrome (WS) is a progressive neurodegenerative disease characterized by early-onset optic atrophy and diabetes mellitus, which can be associated with more extensive central nervous system and endocrine complications. The majority of patients harbour pathogenic WFS1 mutations, but recessive mutations in a second gene, CISD2, have been described in a small number of families with Wolfram syndrome type 2 (WFS2). The defining diagnostic criteria for WFS2 also consist of optic atrophy and diabetes mellitus, but unlike WFS1, this phenotypic subgroup has been associated with peptic ulcer disease and an increased bleeding tendency. Here, we report on a novel homozygous CISD2 mutation (c.215A > G; p.Asn72Ser) in a Moroccan patient with an overlapping phenotype suggesting that Wolfram syndrome type 1 and type 2 form a continuous clinical spectrum with genetic heterogeneity. The present study provides strong evidence that this particular CISD2 mutation disturbs cellular Ca2+ homeostasis with enhanced Ca2+ flux from the ER to mitochondria and cytosolic Ca2+ abnormalities in patient-derived fibroblasts. This Ca2+ dysregulation was associated with increased ER-mitochondria contact, a swollen ER lumen and a hyperfused mitochondrial network in the absence of overt ER stress. Although there was no marked alteration in mitochondrial bioenergetics under basal conditions, culture of patient-derived fibroblasts in glucose-free galactose medium revealed a respiratory chain defect in complexes I and II, and a trend towards decreased ATP levels. Our results provide important novel insight into the potential disease mechanisms underlying the neurodegenerative consequences of CISD2 mutations and the subsequent development of multisystemic disease

    A barrier and techno-economic analysis of small-scale bCHP (biomass combined heat and power) schemes in the UK

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    bCHP (Biomass combined heat and power) systems are highly efficient at smaller-scales when a significant proportion of the heat produced can be effectively utilised for hot water, space heating or industrial heating purposes. However, there are many barriers to project development and this has greatly inhibited deployment in the UK. Project viability is highly subjective to changes in policy, regulation, the finance market and the low cost fossil fuel incumbent. The paper reviews the barriers to small-scale bCHP project development in the UK along with a case study of a failed 1.5MWel bCHP scheme. The paper offers possible explanations for the project's failure and suggests adaptations to improve the project resilience. Analysis of the project's: capital structuring contract length and bankability; feedstock type and price uncertainty, and plant oversizing highlight the negative impact of the existing project barriers on project development. The research paper concludes with a discussion on the effects of these barriers on the case study project and this industry more generally. A greater understanding of the techno-economic effects of some barriers for small-scale bCHP schemes is demonstrated within this paper, along with some methods for improving the attractiveness and resilience of projects of this kind
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