1,720,981 research outputs found
Effects of Surface Layer on Moisture Transport in Cementitious Materials: Experimental Evidence and Simulation Results
No full textHow environmental circumstances influence water repellent treatment efficiency : a case study of Bentheim Sandstone
No full textWater repellents are widely applied directly to the outer surfaces of existing buildings to increase the hydrophobicity and durability of historic facades. Nevertheless, there is little control over the initial moisture content inside masonry and boundary conditions in practice. The fluctuating temperature and moisture content of a wall are inevitable when applying the treatment under natural climatic conditions, therefore the efficiency under realistic application approaches may not be as optimal as in the lab. This research aims to understand how application circumstances affect the hydrophobic efficiency of a siloxane-based water-repellent solvent on sandstone. Samples with different moisture content were treated and cured under different temperature to simulate various field climate conditions in practical applications. The experiments indicate that application temperature and relative humidity have little effect on water-repellent efficiency. The water-repellent product is also effective on saturated walls
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
Hygrothermal performance of CLT subjected to rain loads during construction in Belgium
No full textAs the use of CLT is increasing, it is important to understand how to deal with moisture during construction. Throughout the construction phase it is often not feasible to shield every component and detail from direct rain impingement. This paper investigates what happens to CLT, and spruce wood in general, when it is exposed to rain events, and how fast it dries out afterwards. Subsequently, the implications of incorporating a wetted component into a finished wall system is also investigated. The moisture behaviour of both plain spruce and CLT samples that are exposed outdoors is investigated using the continuous moisture measurement (CMM) setup at the UGent Woodlab in combination with hygrothermal simulations in Delphin 6. Pieces of solid wood and CLT are mounted on load cells that record the weight every 5 minutes, to study the wetting and drying behavior. Hygrothermal simulations are done in Delphin 6 using a climate file that is made from the recorded weather data. This way, the CMM experiments can be recreated in simulations. The goal here is to understand what is happening in the simulations and to look at what influence different parameters have on the moisture content of the samples. Risks of mould and wood decay are investigated, and recommendations are made concerning practical moisture management and risk mititagion for these types of constructions
Combining wood protection options to enhance resistance against decay and improve fire safety of engineered wood products like CLT
No full textBio-based building products are considered key in our future socio-economic environment, since they are a very relevant nature-based solution (NbS) to climate change. The statement of President von der Leyen (European commission) to turn the construction sector into a carbon sink is critical in this respect: bio-based materials should be used on a larger and more targeted scale in the future. The long-term use of materials is therefore very important since we need to improve the lifespan of renewable materials to increase its carbon sink potential. Hence wood is increasingly considered as a main building material. Service life aspects are critical in relation to the EU Construction Products Regulation (CPR). Traditional treatments to protect against fungal decay and the impact of fire are not always performing adequately and often environmental impact has been an important consideration. The option to enhance wood properties using innovative technologies can be combined with better definition of the expectations and requirements. Besides focusing on combined innovative treatments of the wood matrix, also envelope treatments similar to the use of coatings can be envisaged. This all should lead to an increased use of timber and engineered wood products for green building. This paper mainly focusses on the increased use and high potential of CLT (Cross Laminated Timber) and options to use hardwoods and modified wood (like TMT) in relation to moisture dynamics to come to fit-for-purpose material properties even under more hazardous circumstances
A dose-response approach for predicting frost damage with hygrothermal simulations
No full textFreeze-thaw degradation is one of the most prominent degradation risks of brick facades. Considering the difficulties of repairing freeze-thaw damage without replacing the materials, which may not always be an option due to heritage values, it is highly important to quantify the risk of frost damage. Hygrothermal simulations have proven to be a valuable tool to assess the risk of deterioration of building facades. The performance criterion method applied today quantifies the number of critical freeze-thaw cycles. This method is based on frost resistance tests that assume high moisture contents and extremely low frost temperatures. However, building facades often experience milder frost temperatures and lower moisture contents rather than these extreme conditions. A journal article published in 2019 investigated the relationship of frost damage with temperature and moisture content. The experimental study tested freezing temperatures from -2°C to -20°C and moisture saturation degrees from 0.1 to 1.0. This paper investigates whether a correlation can be found between the results of the experimental study and the outcome of hygrothermal simulations. Thereby, an attempt is made to derive a more representative performance criterion for frost damag
MARS : a multiphysics framework for the analysis of cast and printed concrete
No full textPredicting the time-dependent responses of concrete and concrete structures remains a challenging task in the construction sector. While experimental investigation serves as an essential cornerstone for concrete research, by itself it only offers limited insights into the complex time-dependent behaviour of concrete. The complexity is due to the multiple coupled hygro-thermo-chemo-mechanical processes. In the last two decades MARS, a special purpose computational software developed by ES3, has shown the capability of turning such insights accessible. This paper aims to provide a state-of-theart of the MARS capabilities in concrete modelling, enriched with a discussion of some meaningful examples. The multiphysics framework today available in MARS already allows to simulate a wide range of complex phenomena, featuring the long-term performance of ordinary and advanced cementitious materials
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