106,941 research outputs found
Simulation and analysis of the influence of the support structure on a wind turbine gear set
No full textThis work presents the numerical modeling, simulation and analysis of a wind turbine gearset supported by a flexible structure model. Gearboxes based on epicyclic gear trains applied to wind turbines have some advantages, i.e., compactness, robustness and low maintenance requirements. The gearbox is one of its main components because it is responsible for transforming the low angular speed of the rotor into the higher operation speed of the induction generator. Failures in this component cause loss of efficiency and directly impact the energy generated. The gearbox is attached to the nacelle, which is supported by the wind turbine tower. Wind gusts and shear can cause vibration that affects the tower and the nacelle and, therefore, all the components attached to them. To model these phenomena, a detailed model of a 600 kW turbine was built using the MBDyn software. The bearing, gear and the induction generator models were implemented as user-defined modules and were further integrated into the complete model of the wind turbine. Results showed that the gearbox components were affected by the dynamic behavior of the support structure and, therefore, its influence should be accounted for in the design of wind turbines
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
No full textWe 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
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
Contribution of Information and Communication Technology (ICT) in Country’S H-Index
No full textThe aim of this study is to examine the effect of Information and Communication Technology (ICT) development on country’s scientific ranking as measured by H-index. Moreover, this study applies ICT development sub-indices including ICT Use, ICT Access and ICT skill to find the distinct effect of these sub-indices on country’s H-index. To this purpose, required data for the panel of 14 Middle East countries over the period 1995 to 2009 is collected. Findings of the current study show that ICT development increases the H-index of the sample countries. The results also indicate that ICT Use and ICT Skill sub-indices positively contribute to higher H-index but the effect of ICT access on country’s H-index is not clear
Fully Turbulent Mean Velocity Profile for Purely Viscous non-Newtonian Fluids
No full textThe characteristic near wall behavior of turbulent flow of purely-viscous non-Newtonian fluids is discussed for both power-law (P.-L.) and Herschel-Bulkley (H.-B.) rheological models. A proper scaling is presented for H.-B. fluids to establish an analogy with power-law fluids with same flow index. To provide reference data for turbulent flow of non-Newtonian fluids, DNS simulations of power-law fluids are conducted in a rectangular channel for a large range of power-law indices ( = 0.5, 0.69, 0.75, 0.9, 1, 1.2). The DNS data show that the mean velocity profile in the viscous and logarithmic layers follow expressions of the form and respectively, where shows a logarithmic dependency on the flow index.Comparison with some experimental data shows the above formulation to be valid for Reynolds numbers (based on shear velocity) as high as 1000
H-index and research evaluation: A suggested set of components for developing a comprehensive author-level index
No full textThe H-index has been investigated in various studies; this index has many strengths that have made it popular. However, it also has weaknesses, due to which other indicators have been developed. This study aims to identify the strengths and weaknesses of the H-index and provide the minimum set of necessary components for developing a comprehensive author-level index. In this systematic literature review, Scopus, PubMed, Web of Science, Emerald, and ProQuest databases were searched to identify relevant studies. From the number of 14,253 retrieved studies, after two stages of screening, 81 studies were selected according to the eligibility criteria for data extraction. The findings of the study led to the identification of 15 strengths in the three categories of Quality Features, Simplicity, and Suitability, and 13 weaknesses in the six categories of Publications, Citations, Academic Age, Author Credit Allocation, Variety of Fields, and mathematical calculation for H-index. Finally, 28 components were identified as the minimum set of necessary components to develop a comprehensive author-level index to help evaluate researchers more realistically and fairly. The minimum components that need to be considered in developing a comprehensive author-level index can be proposed as follows: Quality Features, Simplicity, Suitability, Publications, Citations, Academic Age, Author Credit Allocation, Variety of Fields, and mathematical calculation
PhD
No full textdissertationA comparative chemical study of several ATP-creatine transphosphorylases from various species was undertaken in order to ascertain those similarities and differences which might ultimately serve to elucidate the mechanism of catalysis, as well as the relation of structure to enzyme function. The muscle-type enzymes from rabbit (Noltman, E, A., Maho-wald, T., and Kuby, S. A. (I962) J. Biol. Chem. 237, 11^6), calf, and human possess very similar amino acid compositions. Likewise, the brain-type enzyme from rabbit and calf are also very similar in composition. However, significant differences exist between the compositions of the muscle-and brain-type isoenzymes isolated from the same species; for example, in the calf there are 8 cysteinyl residues/mole in the muscle isoenzyme vs 10 in the brain, there are 11 fewer lysine residues/mole in the brain-type enzyme, and there are significant increases in a number of aliphatic residues (alanine, proline, leucine). Theoretical titration curves were constructed from the amino acid composition of the calf isoenzymes and the Linderstrom-Lang equation (Mahowald, T. A,, Noltman, E, A,, and Kuby, S. A. (I962) J. Biol.Chem. 237, 1535), assuming that the electrostatic factor is equal to 0. The theoretical curves gave isoionic points for the muscle-, hybrid-, and brain-type enzymes which agreed with the measured isoelectric point (pIo) within 0,5 units (Yue, R, H,, Okabe, K,, Keutel, H., and Kuby. S. A. (1968) Biochem. 7, 4291). In addition, theoretical titration curves were constructed for the brain-type enzyme at 0.02 and 0.1 ionic strength using an iterative procedure to determine the charge on a spherical molecule and assuming an electrostatic factor equal to one-half the theoretical factor. After correction for ion binding, these curves paralleled the measured electrophoretic mobility curves. The amino acid composition and primary structure of the normal and dystrophic human muscle enzymes were investigated in order to determine whether structural change in the dystrophic muscle-type enzyme had taken place. An abnormal presence of three isoenzymes in the dystrophic muscle tissue had been noted earlier (Jacobs, H., Okabe, K., Yue, R., Keutel, H,, Ziter, F., Palmieri, R., Tyler, F., and Kuby, S. A. (1969) Fed, Proc. 28, 346). The amino acid compositions of the two muscle-type enzymes (normal and dystrophic) were identical with the exception of glycine and alanine, which differed at most, by 0.9 residues. Two of the 8 sulfhydryl groups per mole which occur in the normal and dystropliic human muscle-type enzymes are exposed, and can be measured by reaction with DTNB (Jacobs et al. (1969) ibid.). Reaction between iodoacetic acid, iodoacet-amide, DTNB, and the 2 normally reactive -SH groups per mole leads to essentially complete loss of enzymatic activity. This permitted a selective labeling as the S-carboxymethylated derivatives of the 2 reactive sulfhydryl groups per mole with 2-14C-iodoacetate. After thin layer peptide mapping of the tryptic digest of the 2-14C-S-carboxymethylated normal and dystrophic human muscle enzymes, no significant differences could be detected between these two enzymes. Likewise, peptide mapping on Dowex 50-X2 cation exchange column gave essentially identical elution profiles for both enzymes as well as a single radioactive peak which was eluted in approximately 85% and 96% respectively for the normal and dystrophic enzymes. A final comparison was made between the single reactive sulfhydryl group containing tryptic peptides isolated from both enzymes. The amino acid sequence v/as determined to be: Val-Leu-Thr-S-C:.1C-Pro-Ser-Asn-Leu-Gly-Thr-Gly-Leu-Arg after purification by anion exchange for the normal enzyme. Although the sequence of residues 11 and 12 (Gly, Leu) could not be definitely assigned for the dystrophic enzyme, the tryptic peptides appeared to be essentially identical, A similar sequence surrounding the reactive sulfhydryl group has been reported for the rabbit muscle, ox muscle, and brain enzymes by Thomson and coworkers (Nature 203, 267,1964) (Biochem. J. 120,589,1970
Letter from Bob H. Suzuki, President, CSU Pomona, June 13, 1993
No full textA letter from President Bob H. Suzuki thanking guests of a garden reception and asking for their support to fund Michi Nishiura and Walter Weglyn Endowed Chair in Multicultural Studies.These materials are from box 73 and 74 of the Frank Chin Papers. The Frank Chin Papers contain personal and professional correspondence between Frank Chin and Michi Weglyn relating to particular projects on which either author was working as well as files related to the Day of Remembrance Tribute to Michi Weglyn
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