1,720,968 research outputs found
Economic optimization and sensitivity analysis of energy requirements in residential space heating
No full textAn analytical model which relates performance with costs of additional insulation has been developed and the optimum set of insulation values for the various surfaces of a new building has been determined in a generalized form.
On this basis the determinants of the specific energy requirements, corresponding to an optimal level of insulation are identified.
The sensitivity of the energy needs to variations in the building structure or design, in the economic conditions, and in the climate characteristics, is also investigated
A fast code using nonmagnetic measurements for RFX current and magnetic field profile reconstruction
No full textFast identification techniques of the plasma internal magnetic structure are needed for the real time control of the plasma current distribution in magnetic confinement devices. In this paper, a fast identification code using plasma internal nonmagnetic measurements is proposed and applied to the reversed field pinch experiment. The identification tool is based on a force-free ideal magnetohydrodynamic equilibrium model, using a parametric radial profile for the magnetic field and current density. A set of constraints on the internal magnetic distribution are derived from the Faraday rotation data given by a five-chord polarimeter, assuming the plasma density as given by an interferometric diagnostic. The code execution time is about a few second
Improvements to the Plasma Identification in Fusion Devices via Inclusion of Non Magnetic Measurements
No full textThe identification of the plasma magnetic boundary and the internal current profile in the machines for magnetic fusion research is a crucial issue especially in the perspective of a fusion reactor. In the paper the possible beneficial effects on the identification of the plasma parameters coming from the introduction of non magnetic diagnostics are investigated
Integration of magnetic and nonmagnetic measurements for current profile reconstruction in RFX
No full textA crucial issue in magnetically confined plasmas characterized by relevant internal current
redistribution, such as high beta and low field toroidal devices, is the determination of their internal
magnetic structure. The article presents a method for the integration of magnetic and nonmagnetic
measurements in a model which considers a plasma described by stationary ideal
magnetohydrodynamic equilibrium equations, with toroidal and poloidal plasma currents
represented by distributed discrete filaments and current sheets. The model also includes the massive
conductors representing the vessel, the shell, and the machine windings. The discrete current sets are
determined by using as input data the total currents flowing in the plasma, in the windings and in
the vessel, as deduced by external integral magnetic measurements. The obtained filamentary
current sets are then adjusted by imposing further constraints. One of the constraints is given by the
set of local magnetic field measurements provided by external pickup coils. A further and more
significant constraint is imposed by far infrared polarimeter, which gives an integral condition for
each implemented measurement chord. The method is validated by using experimental data from the
reversed field pinch Reversed Field eXperiment, and the results suggest that the current density
distribution is rather different from that usually predicted by conventional data inversion algorithms
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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