A new study of multi-phase mass and heat transfer in natural gas hydrate reservoir with an embedded discrete fracture model

Acknowledgments The authors are grateful to the National Natural Science Foundation of China (51991365), China Geological Survey Project (No. DD20211350), and Guangdong Major Project of Basic and Applied Basic Research (No. 2020B0301030003).Peer reviewedPublisher PD

The impact of mineral compositions on hydrate morphology evolution and phase transition hysteresis in natural clayey silts

The authors are grateful to the National Natural Science Foundation of China, China [51991365]; China Geological Survey Project, China [DD20211350]; Guangdong Major Project of Basic and Applied Basic Research, China [2020B0301030003]; Key Program of Marine Economy Development (Six Marine Industries) of Special Foundation of Department of Natural Resources of Guangdong Province, China [2021]56.Peer reviewedPublisher PD

Review of exploration and production technology of natural gas hydrate

Natural gas hydrate is an ice-like substance which is sometimes called “combustible ice” since it can literally be lighted on fire and burned as fuel. Natural gas hydrate is characterized by widespread distribution, large reserves and little pollution. This paper introduced the distributions of hydrate, hydrate reserves and properties of hydrate. The main exploration methods, such as geophysical exploration and geochemical exploration have been presented. In addition, the main production techniques of natural gas hydrate including depressurization, thermal stimulation and chemical injection have been summed up. Finally, the challenges and outlooks of natural gas hydrate production have been proposed.Cited as: Cui, Y., Lu, C., Wu, M., Peng, Y., Yao, Y., Luo, W. Review of exploration and production technology of natural gas hydrate. Advances in Geo-Energy Research, 2018, 2(1): 53-62, doi: 10.26804/ager.2018.01.0

Research on the Composite Index of the Modern Chinese Energy System

The Chinese government is going to “push ahead the revolution of energy production and consumption, and establish a clean, low-carbon, secure, and efficient energy system”, which points out a direction for the energy industry in the new era. Using the analytic hierarchy process of the system analysis method, we constructed an indicator system of the modern Chinese energy system, and by determining the weighting of each indicator, we obtained the composite index of the modern Chinese energy system, as well as four sub-indexes of clean, low-carbon, secure, and efficient. Then, we investigated policy changes and energy development characteristics of important periods, and performed historical trend analysis. Finally, we forecasted the composite index and four sub-indexes by 2050, and proposed an energy development path and policy suggestions to achieve a modern Chinese energy system as soon as possible

Factors causing low demand for a suburban passenger train in Sekondi-Takoradi

In recent years, there has been a renaissance in urban railway transit supply in Ghana with a railway masterplan seeking to increase the rail network from 947 to 4007.6 km. However, some passenger trains are beginning to face demand downturns, which require empirical investigation. Research on railway operation and passenger demand in Africa is scarce. This paper fills this gap by investigating the causes of declining ridership for the 25 km rehabilitated Sekondi-Takoradi sub-urban train service in Ghana, West Africa. The authors employed a cross-sectional survey of 600 residents in 14 communities within Sekondi-Takoradi and fitted an ordered logit regression model. From the results, the causes of declining ridership are the train\u27s route location, easy access to alternative modes, the pricing system, and the limited supply of only two OD trips per day (operating ≤ 50% of capacity). We recommend a dynamic pricing mechanism, shuttle service, and passenger incentives for increased ridership

Evolution of hydrate habit and formation properties evolution during hydrate phase transition in fractured-porous medium

Acknowledgements The authors are grateful to the National Natural Science Foundation of China (51991365); China Geological Survey Project(No. DD20211350); Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (GML2019ZD0105); Key Program of Marine Economy Development (Six Marine Industries) Special Foundation of Department of Natural Resources of Guangdong Province [2020]047; Guangdong Major Project of Basic and Applied Basic Research (No.2020B0301030003).Peer reviewedPublisher PD

Changes in gut microbiota and cytokines following laparoscopic sleeve gastrectomy are associated with cognitive function improvement

Purpose: Variations of cytokines and gut microbiota diversity with improved cognitive function in patients with obesity following bariatric surgery were poorly understood. The aim of this study was to testify the relationship among gut microbiota, cytokines and cognitive function in patients with obesity before and after laparoscopic sleeve gastrectomy (LSG). Methods: Forty patients were enrolled in this study. Demographics, and serum and stool specimens were collected from all patients before and 3 months after LSG. The Montreal Cognitive Assessment (MoCA) scale, as well as assessment of immediate and delayed memory were used to evaluate self-perceived cognitive improvement after LSG. Results: LSG resulted in significant weight loss and improvement in cognitive functions, as measured by questionnaires. Bariatric surgery tended to increase gut microbiota relative abundance and diversity. The intestinal flora increased in the proportion of Bacteroidetes and Fusobacteria phyla, and decreased in the proportion of Firmicutes, Proteobacteria, and Actinobacteria phyla after LSG. Plasma IL-1β and TNF-α levels were significantly decreased following LSG, while IL-4 was significantly increased. MoCA test scores were significant correlated with IL-4, TNF-α and IL-1β. In addition, Firmicutes had a positive correlation with TNF-α, while Fuscobacteria had a negative correlation with IL-1β. Bacteroidetes was negatively correlated with IL-4. Conclusion: Changes in gut microbiota were positive relationship with cognitive function improvement following LSG. Inflammation cytokines maybe played as a mediator between gut microbiota and cognitive function through gut-microbiota-brain axis