9,815 research outputs found

    Challenges of Primary Frequency Control and Benefits of Primary Frequency Response Support from Electric Vehicles

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    As the integration of wind generation displaces conventional plants, system inertia provided by rotating mass declines, causing concerns over system frequency stability. This paper implements an advanced stochastic scheduling model with inertia-dependent fast frequency response requirements to investigate the challenges on the primary frequency control in the future Great Britain electricity system. The results suggest that the required volume and the associated cost of primary frequency response increase significantly along with the increased capacity of wind plants. Alternative measures (e.g. electric vehicles) have been proposed to alleviate these concerns. Therefore, this paper also analyses the benefits of primary frequency response support from electric vehicles in reducing system operation cost, wind curtailment and carbon emissions

    On determination of the geometric cosmological constant from the OPERA experiment of superluminal neutrinos

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    The recent OPERA experiment of superluminal neutrinos has deep consequences in cosmology. In cosmology a fundamental constant is the cosmological constant. From observations one can estimate the effective cosmological constant Λeff\Lambda_{eff} which is the sum of the quantum zero point energy Λdarkenergy\Lambda_{dark energy} and the geometric cosmological constant Λ\Lambda. The OPERA experiment can be applied to determine the geometric cosmological constant Λ\Lambda. It is the first time to distinguish the contributions of Λ\Lambda and Λdarkenergy\Lambda_{dark energy} from each other by experiment. The determination is based on an explanation of the OPERA experiment in the framework of Special Relativity with de Sitter space-time symmetry.Comment: 7 pages, no figure

    Superconductivity at 36 K in Gadolinium-arsenide Oxides GdO1−x_{1-x}Fx_{x}FeAs

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    In this paper we report the fabrication and superconducting properties of GdO1−x_{1-x}Fx_{x}FeAs. It is found that when x is equal to 0.17, GdO0.83_{0.83}F0.17_{0.17}FeAs is a superconductor with the onset transition temperature Tcon≈_{c}^{on}\approx 36.6K. Resistivity anomaly near 130K was observed for all samples up to x = 0.17, such a phenomenon is similar to that of LaO1−x_{1-x}Fx_{x}FeAs. Hall coefficient indicates that GdO0.83_{0.83}F0.17_{0.17}FeAs is conducted by electron-like charge carriers.Comment: 3 pages, 4 figure

    Pressure Effect on the superconducting properties of LaO_{1-x}F_{x}FeAs(x=0.11) superconductor

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    Diamagnetic susceptibility measurements under high hydrostatic pressure (up to 1.03 GPa) were carried out on the newly discovered Fe-based superconductor LaO_{1-x}F_{x}FeAs(x=0.11). The transition temperature T_c, defined as the point at the maximum slope of superconducting transition, was enhanced almost linearly by hydrostatic pressure, yielding a dT_c/dP of about 1.2 K/GPa. Differential diamagnetic susceptibility curves indicate that the underlying superconducting state is complicated. It is suggested that pressure plays an important role on pushing low T_c superconducting phase toward the main (optimal) superconducting phase.Comment: 7 pages, 4 figure

    The co-creation of social ventures through bricolage, for the displaced, by the displaced

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    Purpose Although scholars have investigated how social entrepreneurs create and develop social enterprises in the penurious stable environment, how they are created in the penurious unstable environment has yet been overlooked. The purpose of this paper is to address this research gap by exploring how internally displaced individuals, despite the lack of resources, create and develop a social enterprise to serve the other displaced population in the war and conflict zones. Design/methodology/approach Underpinned by a biographical research design, in-depth interviews with internally displaced individuals who have created social enterprises in the war and conflict zones were undertaken. Three social entrepreneurs were chosen for this study from three different social enterprises that are created by internally displaced individuals to serve the other internally displaced people of three different countries, namely, Pakistan, Afghanistan and Syria. Findings The single and cross-case analysis found that internally displaced individuals deploy bricolage strategy, for example, reconfiguration of pre-existing resources and competencies (both internal and external), to start up a social venture in the war and conflict zones. They utilise pre-existing internal resources, mainly human capital, and external resources, through a frugal approach towards resources acquisitions. The authors also found that the displaced social entrepreneurs utilise resources of other displaced individuals, for example, networks, volunteers, local knowledge and financial supports mainly from older arrivals, and develop their own enterprise ecosystem within the host location to co-create and co-develop social enterprise and social values for all of them. Research limitations/implications The findings show that internally displaced individuals utilise bricolage strategies to create and develop socially entrepreneurial venture to serve other internally displaced individuals in the war and conflict zones. As the findings are based on three case studies, for confirmatory approach, a quantitative study with a large sample size is necessary. Furthermore, as the differences in economic, cultural and linguistic in between the home and host locations can have impact on the creation and the development of a social venture, they should be considered in the future studies. Originality/value This study contributes to the limited literature and studies on social entrepreneurship, specifically, to the context of unstable penurious environment. It also contributes to the literature on bricolage by extending its application from penurious stable environment to the penurious unstable environment. By exploring what and how internal and external resources are utilised to create and develop a socially entrepreneurial venture in a war and conflict zones, this study has added value to the literature on not only bricolage but also entrepreneurship in war and conflict zones

    Peran Panti Sosial Dalam Membina Dan Meningkatkan Life Skills Anak Terlantar

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    The aim of this research was to explain the role of the orphanage in building and increasing the life skills for homeless children. The method used in this research was descriptive method with quantitative approach. The samples of this research were 50 children. The data were analyzed by using Chi quadrate and Questionnaire. The result showed that: there was a role of the orphanage to build and increase the life skills for homeless children in PSBR Radin Intan. This research proved that when the role of the orphanage more higher, so in building and increasing the life skills for homelsess children will be higher too.Tujuan penelitian ini untuk menjelaskan peran panti sosial dalam membina dan meningkatkan life skills anak kurang mampu dan terlantar di Pelayanan Sosial Bina Remaja (PSBR) Radin Intan. Metode penelitian yang digunakan dalam penelitian ini adalah metode deskriptif dengan pendekatan kuantitatif.Sampel dalam penelitian ini 50 orang. Analisis data menggunakan Chi Kuadrat dan teknik pengumpulan data menggunakan Angket. Hasil penelitian menunjukkan bahwa: terdapat peran panti sosial dalam membina dan meningkatkan life skills anak kurang mampu dan terlantar di Pelayanan Sosial Bina Remaja (PSBR) Radin Intan. Hal ini menunjukkan bahwa semakin tinggi peran panti sosial maka dalam membina dan meningkatkan life skills semakin tinggi juga

    Transverse Velocity Field Measurement in High-Resolution Solar Images Based on Deep Learning

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    To address the problem of the low accuracy of transverse velocity field measurements for small targets in high-resolution solar images, we proposed a novel velocity field measurement method for high-resolution solar images based on PWCNet. This method transforms the transverse velocity field measurements into an optical flow field prediction problem. We evaluated the performance of the proposed method using the Ha and TiO datasets obtained from New Vacuum Solar Telescope (NVST) observations. The experimental results show that our method effectively predicts the optical flow of small targets in images compared with several typical machine- and deep-learning methods. On the Ha dataset, the proposed method improves the image structure similarity from 0.9182 to 0.9587 and reduces the mean of residuals from 24.9931 to 15.2818; on the TiO dataset, the proposed method improves the image structure similarity from 0.9289 to 0.9628 and reduces the mean of residuals from 25.9908 to 17.0194. The optical flow predicted using the proposed method can provide accurate data for the atmospheric motion information of solar images. The code implementing the proposed method is available on https://github.com/lygmsy123/transverse-velocity-field-measurement.Comment: 14 pages, 10 figures, 4 tables. Accepted for publication in Research in Astronomy and Astrophysic
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