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Effects of using tea waste as an additive in the production of solid bricks in terms of their porosity, thermal conductivity, strength and durability
Get PDFIn this paper, we investigated the use of tea waste as an additive in the production of traditional bricks. This could provide several environmental and economic benefits, as well as improving thermal insulation in construction. To this end, we produced brick samples with 0, 5 and 10 w% of tea waste mixed with a clayey material from Teruel (Spain) that was rich in quartz and phyllosilicates and had smaller amounts of carbonates. These samples were fired at 800, 950 and 1100 °C in an electric oven. We then analysed and discussed their chemical, mineralogical, textural and physical-mechanical behaviour and evaluated their durability in response to salt crystallization. The pore system of the bricks was examined using a combination of different analytical techniques (hydric tests, mercury intrusion porosimetry and digital image analysis). We also evaluated their thermal conductivity and observed that an increase in the firing temperature and the amount of tea waste altered the texture of the bricks, increasing their porosity. This happened above all at 1100 °C, where it led to the appearance of a new family of pores and increased the porosity to about 39% for bricks made with 10 w% added tea waste. The increased porosity made the bricks lighter. The bricks made with tea waste showed higher levels of water absorption and poorer mechanical strength. Our results suggest that the addition of tea residues strongly decreases the thermal conductivity and heat diffusion capacity of the bricks. They could therefore be used as lightweight bricks for the thermal insulation of buildings
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
The manufacture of natural hydraulic limes: Influence of raw materials' composition, calcination and slaking in the crystal-chemical properties of binders
Get PDFThis study aims to achieve an in-depth understanding of the manufacturing process of natural hydraulic lime
(NHL) by assessing the influence of raw materials' chemical- mineralogical composition and the effect of the
slaking process. NHLs with variable hydraulicity were manufactured using 56 raw materials from carbonate
outcrops in Andalusia (Spain). This study shows that siliceous limestones with microcrystalline quartz generate
hydraulic phases after calcination. However, when the amount of this reactive silica exceeds 18% by weight, CaO
is not formed, and only calcium silicates appear. It was also found that slaking of NHL leads to partial hydration
of the most reactive calcium silicates, reducing the expected reactivity of the lime. Instead, exposure of NHL
quicklimes to environmental relative humidity promotes the formation of disordered portlandite and reduces the
partial hydration of hydraulic phases. Our findings demonstrate that standard slaking can be replaced by
alternative methods for the studied binders.State Research Agency (SRA) and the
Ministry of Science and Innovation under the Research Project PID2020-
119838RA-I00Regional Ministry of University Research and
Innovation of the Junta de Andalucía and FEDER (a way of making
Europe) B-RNM-188-UGR20Junta de Andalucía Research
Group RNM17
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Mudbricks with tea grounds: A zero CO2 emission option for more sustainable and environmentally-friendly construction
No full textThe traditional brick-firing process, characterized by high energy consumption and significant pollutant emissions, poses environmental challenges that require innovative solutions. This research addresses these challenges by reducing natural resource usage, energy consumption, and gas emissions through the production of mudbricks in which 5–10 wt% of the clayey soil is replaced by tea grounds. This approach uses waste products and efficient manufacturing techniques aimed at achieving zero carbon emissions. The meticulous selection and processing of organic waste draws inspiration from ancient practices in which plant residues were used to enhance the durability and performance of building materials. This study demonstrates that the inclusion of 10 wt% tea grounds enhances the workability of the clay by 15 %, as the lignin and hydrogen bonds in the tea rearrange the molecules, hardening the material in a similar way to the starch retrogradation process in bread. These mudbricks provide..
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
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