A large LNG tank technology system “CGTank®” of CNOOC and its engineering application

AbstractLNG tanks are complex in design and building process and high in costs, so LNG tank technology is one of the most advanced ones in the field of energy, which has been monopolized by foreign companies for a long time. In order to work out LNG tank technology domestically, China National Offshore Oil Corporation (CNOOC for short), the largest LNG importer in China, develops a LNG tank technology system “CGTank®” successfully in reference to the design and construction experience of domestic and foreign companies, after years of scientific research in tackling difficult problems. This system presents four traits as follows. First, a set of calculation software is developed independently by CNOOC, and the tanks in all operating conditions are calculated after 3D hologram and multi-point contact model of fluid-solid coupling effect is built up. Second, earthquake effect research and inner tank check research are improved innovatively by means of response spectrum analysis after European standards are introduced. Third, it is put forward for the first time that the stress strength discrimination standard is based on the principal stress which is obtained by means of the maximum shearing failure theory. And fourth, a large LNG full-capacity tank technology package with completely independent intellectual property right is established. The “CGTank®” system was first applied in the Tianjin LNG demonstration project, which has passed all indicator tests and is now in operation smoothly. The project is provided with the core tank design technology by CNOOC Gas and Power Group and with the EPC by CNOOC Engineering Co., Ltd. The independent LNG tank technology can be applied in a wide scope and it is favorable for impelling domestic production of LNG industry completely

PyPose v0.6: The Imperative Programming Interface for Robotics

PyPose is an open-source library for robot learning. It combines a learning-based approach with physics-based optimization, which enables seamless end-to-end robot learning. It has been used in many tasks due to its meticulously designed application programming interface (API) and efficient implementation. From its initial launch in early 2022, PyPose has experienced significant enhancements, incorporating a wide variety of new features into its platform. To satisfy the growing demand for understanding and utilizing the library and reduce the learning curve of new users, we present the fundamental design principle of the imperative programming interface, and showcase the flexible usage of diverse functionalities and modules using an extremely simple Dubins car example. We also demonstrate that the PyPose can be easily used to navigate a real quadruped robot with a few lines of code

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

Practice and optimization of stable gas supply plan of CNOOC in Guangdong

In order to alleviate the imbalance between the supply and demand of northern China for natural gas in winter, the information of gas infrastructures in Guangdong was sorted out based on the CNOOC's gas production, supply, storage and marketing system in Guangdong, as well as the current interconnection between the system and the Second West-East Gas Pipeline Network. Hydraulic simulation analysis on transient peak-shaving was conducted for the multi-source and multiuser pipeline network with the SPS software to provide a solution for the cooperative scheduling of the "south-to-north" gas transportation based on the surplus capacity of gas infrastructures in Guangdong, the gas sources and the pipeline network. Meanwhile, to facilitate the overcapacity release of the infrastructures such as the offshore gas and LNG receiving terminals of CNOOC, further to realize the stable "south-to-north" gas transportation, the interconnected gas pipeline network was optimized, and an optimization scheme of supplying gas to Shenzhen and Hong Kong by the existing Shenzhen gas pipeline instead of the Second West-East Gas Pipeline was proposed, which provides support for guarantee of safe gas supply in China

Numerical simulation of supply and demand forecasting of multisource and multi-user annular pipeline network

The multi-source and multi-user annular natural gas pipeline network reconstructed from the old natural gas pipelines is characterized with uneven distribution of gas sources, different capacities and characteristics of gas supply, low pressure bearing capacity of the old sections, high pressure of gas supply to user, large gas consumption and great consumption fluctuation. In order to study the supply and demand balance of such pipeline network when it is put into operation in the future, a simulation model of pipeline network was established with the SPS software, including the LNG receiving terminal, the two loops of offshore-gas supply, the pipelines and ancillary facilities, and various end users.Then, the pressure parameters of the offtake stations under the operating conditions of existing natural gas pipelines were simulated, and the maximum relative error between the simulation results and the actual operating data was 1.98%, which verified the reliability of the model. Based on that, simulation was performed for the entire model in accordance with the simulation principles of process, energy efficiency, operation, etc., and the forecast data of supply and demand in different periods of time, as well as the optimal peak shaving mode of the external transportation facilities of the LNG receiving terminal, were obtained. The study results could provide reference for the operation management of the multi-source and multi-user annular natural gas pipeline network

Identification of Lasiodiplodia pseudotheobromae Causing Fruit Rot of Citrus in China

Considering the huge economic loss caused by postharvest diseases, the identification and prevention of citrus postharvest diseases is vital to the citrus industry. In 2018, 16 decayed citrus fruit from four citrus varieties—Satsuma mandarin (Citrus unshiu), Ponkan (Citrus reticulata Blanco cv. Ponkan), Nanfeng mandarin (Citrus reticulata cv. nanfengmiju), and Sugar orange (Citrus reticulata Blanco)—showing soft rot and sogginess on their surfaces and covered with white mycelia were collected from storage rooms in seven provinces. The pathogens were isolated and the pathogenicity of the isolates was tested. The fungal strains were identified as Lasiodiplodia pseudotheobromae based on their morphological characteristics and phylogenetic analyses using the internal transcribed spacer regions (ITS), translation elongation factor 1-α gene (TEF), and beta-tubulin (TUB) gene sequences. The strains could infect wounded citrus fruit and cause decay within two days post inoculation, but could not infect unwounded fruit. To our knowledge, this is the first report of citrus fruit decay caused by L. pseudotheobromae in China

Identification of <i>Lasiodiplodia pseudotheobromae</i> Causing Fruit Rot of Citrus in China

Considering the huge economic loss caused by postharvest diseases, the identification and prevention of citrus postharvest diseases is vital to the citrus industry. In 2018, 16 decayed citrus fruit from four citrus varieties—Satsuma mandarin (Citrus unshiu), Ponkan (Citrus reticulata Blanco cv. Ponkan), Nanfeng mandarin (Citrus reticulata cv. nanfengmiju), and Sugar orange (Citrus reticulata Blanco)—showing soft rot and sogginess on their surfaces and covered with white mycelia were collected from storage rooms in seven provinces. The pathogens were isolated and the pathogenicity of the isolates was tested. The fungal strains were identified as Lasiodiplodia pseudotheobromae based on their morphological characteristics and phylogenetic analyses using the internal transcribed spacer regions (ITS), translation elongation factor 1-α gene (TEF), and beta-tubulin (TUB) gene sequences. The strains could infect wounded citrus fruit and cause decay within two days post inoculation, but could not infect unwounded fruit. To our knowledge, this is the first report of citrus fruit decay caused by L. pseudotheobromae in China