1,721,063 research outputs found
Optical Microscopy and pressure measurements of Enzymatically Induced Calcite Precipitation (EICP) in a microfluidic cell
No full textContent:
This dataset includes raw as well as processed data from three experiments (Exp 1 - 3). Each dataset consists of the readouts from the pressure sensor(s), as logged with the use of QmixElements, raw images, and segmented images.
Log files:
Data in the log files are essentially the raw output of the software QMixElements which is used to operate the syringe pumps and log the pressure sensors. It consists of the columns time, inlet pressure, outlet pressure as well as the flow rates of the two syringes. We need to point out that each pressure sensor has an offset which needs to be accounted for in order to account for the actual pressure in the most accurate way. In order to derive the correct pressure drop (Δp) across the flow cell (outlet pressure - inlet pressure), a two minute period of no flow is applied. It is expected that in the absence of flow the pressure drop across the cell has to be zero and, therefore, the offset of the pressure drop can be determined.
For each experiment there are separate log files for
stage a) initial permeability measurement (Exp[Nr.]_PermInitial)
stage b) continuous injection of reactive solution (Exp[Nr.]_ParallelInjection)
stage c) final permeability measurement (Exp[Nr.]_PermFinal)
In Experiment 2 the final permeability measurement was not conducted, since the cell was clogged, thus the corresponding log file is missing.
Note:
When estimating the permeability reduction over time during stage c), e.g K/K0 = Δp0/Δp(t) , the initial pressure drop (Δp0) is very crucial. Small variations and uncertainties effect the estimated permeability reduction tremendously. Due to the small flow rates in the experiments, the measured initial pressure drop is very small compared to the pressure range of the sensors and falls within the error limit of the sensor itself, casting the measurements quite uncertain. Therefore, it is recommended to back calculate the initial pressure drop based on the initial permeability measurement of stage a) and the flow rate of stage c).
Raw images:
Images taken by optical microscopy are given in the folder rawImages. These are synchronized with the pressure measurements found in the log files from QMixElements, which is realized by the following naming convention of each image: Exp[Nr.]_[timestamp in sec]. The timestamp in seconds corresponds to the time in the log file. While in Experiment 1 and 2 images were captured at 0.1 frames per second (fps), in Experiment 3 the frame rate was set to 1 fps. In Experiment 3 some images got dumped during the recording. The physical resolution of the images are: 3.34 μm/pixel (Experiment 1), 3.36 μm/pixel (Experiment 2) and 3.17 μm/pixel (Experiment 3). These were calculated based on the known length of the domain divided by the number of pixels.
Segmented images:
The segmented images are saved in the folder processedImages. Not all of the raw images were processed: The first processed image has the timestamp of 420 seconds and corresponds to the time when the continuous injection of the reactant solution started. One image every five minutes were processed. These images were also flipped vertically compared to the raw images
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
Hydraulic fracturing in unconventional gas reservoirs: risks in the geological system part 1
No full textHydraulic fracturing of unconventional gas reservoirs rapidly developed especially in the USA to an industrial scale during the last decade. Potential adverse effects such as the deterioration of the quality of exploitable groundwater resources, areal footprints, or even the climate impact were not assessed. Because hydraulic fracturing has already been practised for a long time also in conventional reservoirs, the expansion into the unconventional domain was considered to be just a minor but not a technological step, with potential environmental risks. Thus, safety and environmental protection regulations were not critically developed or refined. Consequently, virtually no baseline conditions were documented before on-site applications as proof of evidence for the net effect of environmental impacts. Not only growing concerns in the general public, but also in the administrations in Germany promoted the commissioning of several expert opinions, evaluating safety, potential risks, and footprints of the technology in focus. The first two publications of the workgroup "Risks in the Geological System" of the independent "Information and Dialogue process on hydraulic fracturing" (commissioned by ExxonMobil Production Deutschland GmbH) comprises the strategy and approaches to identify and assess the potential risks of groundwater contamination of the exploitable groundwater system in the context of hydraulic fracturing operations in the Munsterland cretaceous basin and the Lower Saxony Basin, Germany. While being specific with respect to local geology and the estimation of effective hydraulic parameters, generalized concepts for the contamination risk assessment were developed. The work focuses on barrier effectiveness of different units of the overburden with respect to the migration of fracking fluids and methane, and considers fault zones as potential fluid pathway structures
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