1,720,956 research outputs found
Mineralogical, geochemical and microfabric evidences of gypsum crusts: a case study from Budapest
No full textHigh levels of SO2 and particulate pollution enable the rapid development of gypsum-rich weathering crusts in Budapest. Two types of white crusts, thin and thick ones, and two forms of black crusts, laminar and framboidal ones, were studied in limestone buildings of the parliament and Citadella. The percentage of crust cover and damage categories were documented on selected walls. Petrographic, XRD, XRF and sulphur isotope analyses were performed under laboratory conditions to understand the mechanism of crust formation. White crusts found both on exposed and sheltered walls display a calcite-rich layer with gypsum, while black crusts are enriched with gypsum. The sulphur isotopic composition of white and black crusts overlaps, but the crusts are slightly enriched in heavy isotopes compared to rainwater. S content, Si/Al ratios and particulates in black crusts suggest that air pollution (SO2, dust) contributes to black crust formation. The accumulation of sulphur and Zn enrichment of white crusts were also documented indicating that under high pollution levels, even these compound can accumulate on exposed facades
Physical and mineralogical changes of Hungarian monumental stones exposed to different conditions: stone-testing in-situ and under laboratory conditions
No full textThe Székesfehérvár Ruin Garden is a unique assemblage of monuments belonging to the cultural
heritage of Hungary due to its important role in the Middle Ages as the coronation and burial
church of the Kings of the Hungarian Christian Kingdom. It has been nominated for “National
Monument” and as a consequence, its protection in the present and future is required. Moreover, it
was reconstructed and expanded several times throughout Hungarian history. By a quick overview
of the current state of the monument, the presence of several lithotypes can be found among the
remained building and decorative stones. Therefore, the research related to the materials is crucial
not only for the conservation of that specific monument but also for other historic structures in
Central Europe.
The current research is divided in three main parts: i) description of lithologies and their
provenance, ii) physical properties testing of historic material and iii) durability tests of analogous
stones obtained from active quarries. The survey of the National Monument of Székesfehérvár,
focuses on the historical importance and the architecture of the monument, the different
construction periods, the identification of the different building stones and their distribution in the
remaining parts of the monument and it also included provenance analyses. The second one was
the in situ and laboratory testing of physical properties of historic material. As a final phase
samples were taken from local quarries with similar physical and mineralogical characteristics to
the ones used in the monument. The three studied lithologies are: fine oolitic limestone, a coarse
oolitic limestone and a red compact limestone. These stones were used for rock mechanical and
durability tests under laboratory conditions.
The following techniques were used:
a) in-situ: Schmidt Hammer Values, moisture content measurements, DRMS, mapping
(construction ages, lithotypes, weathering forms)
b) laboratory: petrographic analysis, XRD, determination of real density by means of helium
pycnometer and bulk density by means of mercury pycnometer, pore size distribution by mercury
intrusion porosimetry and by nitrogen adsorption, water absorption, determination of open
porosity, DRMS, frost resistance, ultrasonic pulse velocity test, uniaxial compressive strength test
and dynamic modulus of elasticity.
The results show that initial uniaxial compressive strength is not necessarily a clear indicator of
the stone durability. Bedding and other lithological heterogeneities can influence the strength and
durability of individual specimens. In addition, long-term behaviour is influenced by exposure
conditions, fabric and, especially, the pore size distribution of each sample. Therefore, a statistic
evaluation of the results is highly recommended and they should be evaluated in combination with
other investigations on internal structure and micro-scale heterogeneities of the material, such as
petrographic observation, ultrasound pulse velocity and porosimetry. Laboratory tests used to
estimate the durability of natural stone may give a good guidance to its short-term performance
but they should not be taken as an ultimate indication of the long-term behaviour of the stone.
The interdisciplinary study of the results confirms that stones in the monument show deterioration
in terms of mineralogy, fabric and physical properties in comparison with quarried stones.
Moreover stone-testing proves compatibility between quarried and historical stones. Good
correlation is observed between the non-destructive-techniques and laboratory tests results which
allow us to minimize sampling and assessing the condition of the materials. Concluding, this
research can contribute to the diagnostic knowledge for further studies that are needed in order to
evaluate the effect of recent and future protective measures
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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