The Scholarly Database and its utility for scientometrics research

The Scholarly Database aims to serve researchers and practitioners interested in the analysis, modelling, and visualization of large-scale data sets. A specific focus of this database is to support macro-evolutionary studies of science and to communicate findings via knowledge-domain visualizations. Currently, the database provides access to about 18 million publications, patents, and grants. About 90% of the publications are available in full text. Except for some datasets with restricted access conditions, the data can be retrieved in raw or pre-processed formats using either a web-based or a relational database client. This paper motivates the need for the database from the perspective of bibliometric/scientometric research. It explains the database design, setup, etc., and reports the temporal, geographical, and topic coverage of data sets currently served via the database. Planned work and the potential for this database to become a global testbed for information science research are discussed at the end of the paper.     

Crystallization of LiNbO3 and NaNbO3 in niobiosilicate glass–ceramics

Although glass–ceramics have been widely explored for their thermal stability and mechanical properties, they also offer unique symmetry-dependent properties such as piezoelectricity and pyroelectricity through controlled crystallization of a polar phase. This work examines crystallization of LiNbO₃ in a 35SiO₂–30Nb₂O₅–35Li₂O mol% composition and crystallization of LiNbO₃ and NaNbO₃ in a 35SiO₂–30Nb₂O₅–25Li₂O–10Na₂O mol% composition. Crystallization kinetics are examined using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) theory where the Avrami exponent, n, is calculated to be 1.0–1.5. Microscopical analysis shows dendritic morphology, which when combined with the JMAK analysis, suggests diffusion-controlled one-dimensional growth. Adding Na₂O to the glass composition increases the inter-diffusivity of ions which causes LiNbO₃ to crystallize faster and lowers the activation energy of transformation from 1054 ± 217 kJ/mol in the ternary composition to 882 ± 212 kJ/mol. Time-temperature-transformation diagrams are presented which show that the temperature for maximum rate of transformation for LiNbO₃ is ∼650°C and for NaNbO₃ is ∼715°C.     

‘Seed + expand’: a general methodology for detecting publication oeuvres of individual researchers

The study of science at the individual scholar level requires the disambiguation of author names. The creation of author’s publication oeuvres involves matching the list of unique author names to names used in publication databases. Despite recent progress in the development of unique author identifiers, e.g., ORCID, VIVO, or DAI, author disambiguation remains a key problem when it comes to large-scale bibliometric analysis using data from multiple databases. This study introduces and tests a new methodology called seed + expand for semi-automatic bibliographic data collection for a given set of individual authors. Specifically, we identify the oeuvre of a set of Dutch full professors during the period 1980–2011. In particular, we combine author records from a Dutch National Research Information System (NARCIS) with publication records from the Web of Science. Starting with an initial list of 8,378 names, we identify ‘seed publications’ for each author using five different approaches. Subsequently, we ‘expand’ the set of publications in three different approaches. The different approaches are compared and resulting oeuvres are evaluated on precision and recall using a ‘gold standard’ dataset of authors for which verified publications in the period 2001–2010 are available.     

Reducing sample size by tightening test conditions

The inspection of measurement devices according to statistical sampling plans allows conclusions to be drawn about the reliability of a whole population of devices. However, confirming high reliability levels requires large sample sizes and is thus expensive or even infeasible. For example, a reliability of 99.5% can only be guaranteed with 90% confidence by inspecting each item in a population of 280 (see ISO 2859‐2). When reliability is judged by not exceeding a certain threshold, this research provides a convenient solution allowing considerably more efficient sampling plans. Under certain distributional assumptions, in particular, we have proved that if 100q% of a population meets a tighter threshold Δ/γ, then at least 100p% of the population meets threshold Δ(with p>q, γ>1). The importance and effect of different distributional assumptions are demonstrated and relevant scenarios for the parameters (p,q,γ) presented. Verifying that a smaller portion of devices comply requires smaller sample sizes. Costs may thus decrease when more stringent specifications are verified. For example, up to 98% of utility meters in Germany are required to measure correctly at inspections, to ensure a reliability of 95% in the future. Instead of applying costly sampling plans to meters in use to demonstrate these high reliability levels, this research enables the sample size to be reduced, eg, by half.     

Kinetics of Liquid/Liquid Extraction of Europium(III) Cation by Two Malonic Diamides

In the framework of the DIAMEX separation process, the kinetics of extraction of Eu(III) ion by two diamides, DMDBTDMA and DMDOHEMA, have been studied using the rotating membrane cell technique. The kinetics with DMDBTDMA from a nitric acid solution were found to be very fast, in keeping with a previous work using the Nitsch cell, and in disagreement with another work using a Lewis-type cell. A simple model for turbulent transport in the latter cell is proposed to interpret this result. The extraction kinetics with DMDOHEMA was found to be slower than with DMDBTDMA at 22°C. The activation energy of the interfacial reaction was deduced from experiments at 11°C, 22°C, and 33°C. The activation energy of the distribution ratio is shown to have a particular effect on that of the overall kinetic rate constant in the general case.     

Molecular characterization of Listeria monocytogenes from natural and urban environments

Characterization of 80 Listeria monocytogenes isolates from urban and natural environments differentiated 7 and 26 EcoRI ribotypes, respectively. Whereas the majority of isolates from the natural environment represented L. monocytogenes lineage II (12 of 13 isolates), urban isolates grouped evenly into lineages I and II (32 and 33 isolates, respectively) and included two lineage III isolates. Multilocus sequence typing of all natural isolates and a randomly selected subset of 30 urban isolates showed a higher overall diversity (Simpson index of discrimination [D] of 0.987 and 0.920, respectively) than did EcoRI ribotyping (D = 0.872 and 0.911, respectively). Combined analysis with ribotype and lineage data for 414 isolates from farm sources, 165 isolates from foods and food-processing environments, and 342 human clinical isolates revealed that lineage I was significantly more common among human (P < 0.0001) isolates, whereas lineage II was more common among isolates from the natural environment, farms, and foods (P < or = 0.05). Among a total of 92 ribotypes, 31 showed significant associations with specific isolate sources. One ribotype (DUP-1039C) was significantly associated with both natural environments and farms. A spatial analysis showed a marginal association between locations in the natural environment positive for L. monocytogenes and a proximity to farms. Our data indicate that (i) L. monocytogenes strains from different sources show a high level of diversity; (ii) L. monocytogenes subtypes differ significantly in their associations with different environments, even though populations overlap; and (iii) a higher proportion of isolates from environmental sources than from human clinical cases can be classified into L. monocytogenes lineage II, which supports the classification of this lineage as an environmentally adapted subgroup.     

Chemicals and polymers from biomass

While fossil energy prices remain relatively low and agricultural prices are maintained at a relatively high level as a result of production costs, the use of purpose grown crops as a source of fuels requires subsidies, tax support or other financial incentives to be viable. In the short term, the use of agricultural and forest raw materials as industrial raw materials for production of higher value products appears more attractive. However, simple substitution of a petroleum-based product by one derived from plants is seldom possible. Options are reviewed, covering both established commercial activities (such as starch, vegetable oil, paper-pulp and natural fibres), as well as the extensive research and development activities that should lead to new crops, new products and new markets.     

Explicating Affordances: A Conceptual Framework for Understanding Affordances in Communication Research

This study aims to clarify inconsistencies regarding the term affordances by examining how affordances terminology is used in empirical research on communication and technology. Through an analysis of 82 communication‐oriented scholarly works on affordances, we identify 3 inconsistencies regarding the use of this term. First, much research describes a particular affordance without engaging other scholarship addressing that affordance. Second, several studies identify “lists” of affordances without conceptually developing individual affordances within those lists. Third, the affordances perspective is evoked in situations where the purported affordance does not meet commonly accepted definitions. We conclude with a set of criteria to aid scholars in evaluating their assumptions about affordances and to facilitate a more consistent approach to its conceptualization and application.     

Combined ellipsometry and X-ray related techniques for studies of ultrathin organic nanocomposite films

Ultrathin nanocomposite films of nitrobenzene on silicon were analyzed by Infrared Spectroscopic Ellipsometry (IRSE), X-ray reflectivity (XRR) and X-ray standing waves (XSW) before and after evaporation of gold. Infrared Spectroscopic Ellipsometry measurements were performed for identification of adsorbates and for investigation of the molecular orientation. Results for film thickness were correlated with XRR measurements. Further, XSW measurements of elements incorporated in nitrobenzene (C, N, and O) were performed with soft X-rays. The combination of the different methods allowed to confirm a model for the electrochemically deposited nitrobenzene films before and after gold evaporation. The characterization by XRR and XSW scans using hard X-rays showed that gold had penetrated into the nitrobenzene film and thus changed density and optical properties of this layer significantly. A depth profile correlated to the electron density is deduced from the XRR measurements. This profile allows to localize—in vertical direction—gold islands within the composite film.