1,721,211 research outputs found
Oxide-ion and proton conducting electrolyte materials for clean energy applications: structural and mechanistic features
No full textThis critical review presents an overview of the various classes of oxide materials exhibiting fast oxide-ion or proton conductivity for use as solid electrolytes in clean energy applications such as solid oxide fuel cells. Emphasis is placed on the relationship between structural and mechanistic features of the crystalline materials and their ion conduction properties. After describing well-established classes such as fluorite- and perovskite-based oxides, new materials and structure-types are presented. These include a variety of molybdate, gallate, apatite silicate/germanate and niobate systems, many of which contain flexible structural networks, and exhibit different defect properties and transport mechanisms to the conventional materials. It is concluded that the rich chemistry of these important systems provides diverse possibilities for developing superior ionic conductors for use as solid electrolytes in fuel cells and related applications. In most cases, a greater atomic-level understanding of the structures, defects and conduction mechanisms is achieved through a combination of experimental and computational technique
Synthesis, Characterization and Antibacterial Activity on Dinuclear Schiff-base Macrocyclic Metal Complexes
No full textSchiff-bases and their dinuclear metal complexes have been extensively received special attention because of their wide range of applications including catalysts, medicine crystal engineering, anti-corrosion agent, and biological activities [1]. Dinuclear macrocyclic lead (II) complex, Pb2L1(SCN)4 was synthesized by template condensation of pyridine-2,6-dicarboxaldehyde and 1,2-bis (2-aminoethoxy) ethane in presence of Pb(SCN)2 as the metal source, here L1 is tetra-Schiff-base macrocycle. Transmetallation treatment of Pb2L1(SCN)4 with Co(PF6)2.6H2O produced the new complex, Co2L1(SCN)4 [2]. Reduction of lead (II) complex gave new reduced tetra-Schiff-base macrocyclic ligand, L2[3]. All the metal complexes and ligand were characterized by UV-Visible, FT-IR, 1H NMR spectroscopy. The antibacterial activities against some pathogenic gram positive and gram negative bacteria were studied by cylinder disk diffusion method. The complexes were found to inhibit the growth of bacteria
Satellite based internet education delivery and e-learning objects evaluation: SOI Asia and CodeWitz perspective
No full textDevelopment of Internet based distance education facilities and e-Learning objects development is commensurate with the capacity building and modernization process of Bangladesh University of Engineering and Technology (BUET) and congruent with the long term objective of the institution regarding facilitation of continuing education satisfying the temporal and spatial constraints. To fulfill the objectives, BUET has established satellite based School On the Internet (SOI) project and become active partner in the global e-Learning object development program through CodeWitz project. In this paper we present, (i) the technology used to deliver the real time lectures through SOI, (ii) the content and quality assessment of the delivered lecture by the participants and its overall impact in the human resource development in BUET, (iii) the development of e-Learning objects for different programming languages, and (iv) the quality evaluation of the developed objects and interest from other stakeholders of the CodeWitz project
Diminishing seismic effect on buildings using bearing isolation
No full textAdopting suitable seismic protection techniques is presently a foremost
concern worldwide and has become a governing principle in the growing construction
industry globally. Thus, a rapid upsurge in infrastructure development in seismic-prone
areas requires proper treatment for building structures. Therefore, the aim of the study is
to incorporate a rubber bearing isolation device in a building base in order to diminish
the seismic effect on the superstructure. The changes of structural parameters and
responses of fixed-based buildings for applying High Damping Rubber Bearing (HDRB)
are investigated under site-specific ground excitation. Twenty representative buildings
have been used to examine the responses employing four types of HDRB systems. The
study reveals that the HDRB makes the structure more flexible, offering reduced
structural responses. The introduction of HDRB may help to decrease floor moment by
31~55%, which can allow the structures to withstand comparatively high seismic tremors
safely and efficiently. The base isolated structures experience significant lateral shift
between 87.15 and 130.15 mm, and relative floor displacement is below 3% because of
additional flexibility. The effective inertia height for the BI buildings remains under twothirds of building elevation showing triangular distribution concentrating to the top story
level. The reduction in forces, moments, and relative displacements of the structural
members by applying HDRB can ensure economic design and higher structural safety
against seismic excitation
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
