1,720,965 research outputs found
CO2 capture from offshore oil installations: An evaluation of alternative methods for deposition with emphasis on carbonated water injection
Get PDFCapture and storage of CO2 from gas turbine power plants can be an alternative to electrification from shore to reduce the emissions from petroleum production facilities on the Norwegian Continental Shelf. The objective of this work was to analyse and rank various options for storage using technical economic analyses. The following alternatives were considered:
1. Dissolution of CO2 in sea water and aquifer storage of carbonated water
2. Injection of pure CO2 into an aquifer
3. Compression of CO2 and pipeline transport to a collection centre
4. Liquefaction of CO2 and ship transport to a collection centre
5. Dissolution of CO2 in sea water and injection into oil fields (carbonated water injection, CWI)
For each alternative the investment costs and operating costs were estimated, and the net present values were determined. Credit for saved CO2 tax was included as incomes for all alternatives. The CO2 tax is expected to increase significantly from present level to Year 2030. For Alternative 5, CWI into oil fields, incomes from incremental oil production was also included. This required more comprehensive analyses. Using both a heterogeneous and a homogeneous field scale simulation model incremental oil productions and CO2 retention were estimated for CWI into both green and brown fields cases.
The economic calculations show that alternatives 1 – 4 have negative net present values. A higher future CO2 tax than presently envisaged will be needed to make the alternatives economically viable. All cases related to Alternative 5 (project lifetime, heterogeneous and homogeneous reservoir models, green and brown fields) exhibit positive net present values due to incremental oil production. Most, but not all, injected CO2 remained in the reservoir, depending on the injection period.
Oxygen in the captured CO2, formation of gas hydrates and corrosion of well materials may cause operational problems of injecting sea water with dissolved CO2. These aspects have been briefly discussed. Some additional measures may have to be taken to alleviate undesired effects, but none of the issues are likely to prohibit implementation of CWI.
The results obtained suggest that CWI into producing oil reservoirs offers an economic viable and safe way for disposal of CO2 captured from offshore petroleum production plants provided that a capture plant can be installed, and that the remaining lifetime of the reservoir is so long that the benefits of improved oil recovery can be realised.publishedVersio
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
Assessing the value of seismic monitoring of CO2 storage using simulations and statistical analysis
Get PDFSuccessful storage of CO2 in underground aquifers requires robust monitoring schemes for detecting potential leakage. To aid in this challenge we propose to use statistical approaches to gauge the value of seismic monitoring schemes in decision support systems. The new framework is based on geostatistical uncertainty modeling, reservoir simulations of the CO2 plume in the aquifer, and the associated synthetic seismic response for both leak and seal scenarios. From a large set of simulations we assess the leak and seal conditional probabilities given seismic data over time, and build on this to compute the value of information of the seismic monitoring schemes. The Smeaheia aquifer west of Norway is used to exemplify the approach for early leakage detection and decision support regarding CO2 storage projects. For this case study, we find that the optimal monitoring time is about 10 years after injection starts.publishedVersio
Quality Ranking of the Best CO2 Storage Aquifers in the Nordic Countries
No full textRanking of CO2 storage sites in the Nordic countries has previously been reported from the NORDICCS project. The ranking was based on geological characteristics of reservoir and seal, data coverage and safety evaluation of the storage complex. Estimated storage capacity were included but not taken into account in the ranking except if two storage sites were equally ranked. This paper presents a method for evaluating knowledge gaps for a storage site based on characterisation and assessment criteria presented in the EU CCS Directive, and a new updated ranking is presented where knowledge gaps are taken into account
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
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
- …
