RELIABILITY OF DISSIMILAR METAL WELDS SUBJECTED TO SULFIDE STRESS CRACKING

Serious concerns have been raised in recent years in the Oil & Gas Industry about the reliability of Dissimilar Metal Welds (DMWs) in sour service. The primary reason for these concerns is because DMW joints exhibit small-localized hard zones that are susceptible to Sulfide Stress Cracking (SSC). In the open literature some methods such as preheating have been suggested to overcome the problem of hard zone formation. The objective of this study is to assess the effect of Sulfide Stress Cracking (SSC) on the reliability (mechanical integrity) of DMWs specimens fabricated with different preheat temperatures and electrodes exposed to sour service environment. The National Association of Corrosion Engineers (NACE) Standard Tensile Test TM 01-77-96 Method A was used to determine the influence of SSC on DMWs in a systematic manner. Test results show considerable improvement in the Time-To- Failure as a result of the preheating methods used. However, it does not appear that the hard zones can be reliably eliminated for manual welding methods, even with the nickel-base electrode, and the optimum preheat temperature. Metallographic Examination and Scanning Electron Microscope Characterization were also used to assess the susceptibility and the failure modes

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

RELIABILITY OF DISSIMILAR METAL WELDS SUBJECTED TO SULFIDE STRESS CRACKING

Serious concerns have been raised in recent years in the Oil & Gas Industry about the reliability of Dissimilar Metal Welds (DMWs) in sour service. The primary reason for these concerns is because DMW joints exhibit small-localized hard zones that are susceptible to Sulfide Stress Cracking (SSC). In the open literature some methods such as preheating have been suggested to overcome the problem of hard zone formation. The objective of this study is to assess the effect of Sulfide Stress Cracking (SSC) on the reliability (mechanical integrity) of DMWs specimens fabricated with different preheat temperatures and electrodes exposed to sour service environment. The National Association of Corrosion Engineers (NACE) Standard Tensile Test TM 01-77-96 Method A was used to determine the influence of SSC on DMWs in a systematic manner. Test results show considerable improvement in the Time-To- Failure as a result of the preheating methods used. However, it does not appear that the hard zones can be reliably eliminated for manual welding methods, even with the nickel-base electrode, and the optimum preheat temperature. Metallographic Examination and Scanning Electron Microscope Characterization were also used to assess the susceptibility and the failure modes

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical science. © The Author(s) 2019. Published by Oxford University Press