1,720,998 research outputs found
resolution of mixtures of organic acids by conductometric titrations in 2-methoxyethanol
No full textA study has been made on the conductometric titrations of mixtures of organic acids in 2-methoxyethanol as solvent and with 0.01 M DPG as standard titrant. Conductometric titration curves are pèresented and discussed for both aliphatic and aromatic mono- and dicarboxylic acids, and para- and meta-substituted benzenseleninic acids in binary, ternary, and quaternary mixtures. The solvent is suitable for the resolution of acid mixtures in some cases where a quantitative determination is impossible in aqueous solutions owing to very close pK values
Synthesis and characterization of ruthenium(III) complexes with para-and meta-substituted benzenseleninic acids as ligands
No full textA number of complexes of ruthenium(III) with para- and meta-substituted benzeneseleninic acids, XC6H4SeO2H (X = H, m-Br, p-Br, p-CH3, m-Cl, p-Cl) are reported. The recently prepared compounds are characterized through elemental analyses, near and far i.r. spectroscopy, electronic spectra, conductivity measurements, thermal analyses (TG and DTG) and magnetic susceptibility measurements. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of the crystal field theory; the nephelauxetic parameters are all indicative of an appreciable metal-ligand covalency. The i.r. results point to a O, O′-seleninato coordination for all the complexes; in particular the presence of three SeO bands with the irreducible representation A2 + 2E in the i.r. spectra of the trisderivatives of the type Ru (XC6H4SeO2)3 suggests an octahedral configuration with D3 symmetry. The complexes of the type Ru (XC6H4SeO2)2 Y (Y = Cl, Br) are polymeric octahedral with bridging halides
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
Ergonomic analysis of the effects of a telehandler's active suspended cab on whole body vibration level and operator comfort
No full textIntroduction: Exposure to whole body vibration (WBV) is one of the most important risks for musculoskeletal disorders (MSDs). The objective of the study was to investigate whether an active cab suspension system fitted on a telehandler was effective in reducing WBV and in improving comfort. Method: Sixteen male healthy professional operators drove a telehandler on a 100 m ISO 5008 smooth track at two different speeds (5 and 12 kph) with activated and deactivated cab suspension system. Adopting an ergonomic approach, different aspects of the human-machine interaction were analyzed: 1) vibration transmissibility, 2) subjective ratings of general comfort and local body discomfort, and 3) anthropometric characteristics of the users. Results: A series of ANCOVAs showed that the suspension system was effective in reducing WBV at both speeds but did not affect the perception of comfort by the operators. Moreover, individuals with higher Body Mass Index (BMI) experienced more comfort. Some neck/shoulder and lumbar complaints and perceived hard jolts seemed to remain even when the system was activated. No correlations were found between objective and subjective measures. Practical applications: Results suggest that the operators, given their wide range of physical variability, may need more adjustable or customizable WBV reduction systems
- …
