39 research outputs found
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Dynamical Link between the BarentsâKara Sea Ice and the Arctic Oscillation
The recent accelerated Arctic sea ice decline has been proposed as a possible forcing factor for midlatitude circulation changes, which can be projected onto the Arctic Oscillation (AO) and/or North Atlantic Oscil- lation (NAO) mode. However, the timing and physical mechanisms linking AO responses to the Arctic sea ice forcing are not entirely understood. In this study, the authors suggest a connection between November sea ice extent in the Barents and Kara Seas and the following winterâs atmospheric circulation in terms of the fast sea ice retreat and the subsequent modification of local airâsea heat fluxes. In particular, the dynamical processes that link November sea ice in the Barents and Kara Seas with the development of AO anomalies in February is explored. In response to the lower-tropospheric warming associated with the initial thermal effect of the sea ice loss, the large-scale atmospheric circulation goes through a series of dynamical adjustment processes: The decelerated zonal-mean zonal wind anomalies propagate gradually from the subarctic to midlatitudes in about one month. The equivalent barotropic AO dipole pattern develops in January because of waveâmean flow interaction and firmly establishes itself in February following the weakening and warming of the stratospheric polar vortex. This connection between sea ice loss and the AO mode is robust on time scales ranging from interannual to decadal. Therefore, the recent winter AO weakening and the corresponding midlatitude climate change may be partly associated with the early winter sea ice loss in the Barents and Kara Seas
Recovery and treatment of fracturing flowback fluids in the Sulige Gasfield, Ordos Basin
AbstractCentralized and group well deployment and factory-like fracturing techniques are adopted for low-permeability tight sandstone reservoirs in the Sulige Gasfield, Ordos Basin, so as to realize its efficient and economic development. However, environmental protection is faced with grim situations because fluid delivery rises abruptly on site in a short time due to centralized fracturing of the well group. Based on the characteristics of gas testing after fracturing in this gas field, a fracturing flowback fluid recovery and treatment method suitable for the Sulige Gasfield has been developed with the landform features of this area taken into account. Firstly, a high-efficiency well-to-well fracturing flowback fluid recovery and reutilization technique was developed with multi-effect surfactant polymer recoverable fracturing fluid system as the core, and in virtue of this technique, the treatment efficiency of conventional guar gum fracturing fluid system is increased. Secondly, for recovering and treating the end fluids on the well sites, a fine fracturing flowback fluid recovery and treatment technique has been worked out with âcoagulation and precipitation, filtration and disinfection, and sludge dewateringâ as the main part. Owing to the application of this method, the on-site water resource utilization ratio has been increased and environmental protection pressure concerned with fracturing operation has been relieved. In 2014, field tests were performed in 62 wells of 10 well groups, with 32980Â m3 cumulative treated flowback fluid, 17160Â m3 reutilization volume and reutilization ratio over 70%. Obviously, remarkable social and economical benefits are thus realized
Kiss the Baby for the Nurseâs Sake? - Guaranteeing Employeesâ Stock Purchase against Loss Program
This paper investigates the unique and interesting phenomenon of the Guaranteed Employees Stock Purchase against Loss Program (GESPLP) that Chinese companies have initiated in recent years. The GESPLP encourages employees to buy shares and ensures them against losses for 12 months. We comprehensively investigate the direct reason, root reason, motivation, and consequences of this program. Based on manually collected data from all firms issued the GESPLP, we provide convincing evidence that companies with lower stock returns and higher stock pledges are more likely to initiate a GESPLP. The market reaction to the announcement of a GESPLP is positive in the short run. However, stock prices gradually revert to their pre-GESPLP level. Finally, our findings support the conjecture that the GESPLP is used to relieve the pressure of margin calls on corporate insiders' stock pledging in the short term. In a relatively long run, we observe the GESPLP indeed helps controlling shareholders reduce pledging level
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Full Access Dynamical Link between the BarentsâKara Sea Ice and the Arctic Oscillation
The recent accelerated Arctic sea ice decline has been proposed as a possible forcing factor for midlatitude circulation changes, which can be projected onto the Arctic Oscillation (AO) and/or North Atlantic Oscillation (NAO) mode. However, the timing and physical mechanisms linking AO responses to the Arctic sea ice forcing are not entirely understood. In this study, the authors suggest a connection between November sea ice extent in the Barents and Kara Seas and the following winterâs atmospheric circulation in terms of the fast sea ice retreat and the subsequent modification of local airâsea heat fluxes. In particular, the dynamical processes that link November sea ice in the Barents and Kara Seas with the development of AO anomalies in February is explored. In response to the lower-tropospheric warming associated with the initial thermal effect of the sea ice loss, the large-scale atmospheric circulation goes through a series of dynamical adjustment processes: The decelerated zonal-mean zonal wind anomalies propagate gradually from the subarctic to midlatitudes in about one month. The equivalent barotropic AO dipole pattern develops in January because of waveâmean flow interaction and firmly establishes itself in February following the weakening and warming of the stratospheric polar vortex. This connection between sea ice loss and the AO mode is robust on time scales ranging from interannual to decadal. Therefore, the recent winter AO weakening and the corresponding midlatitude climate change may be partly associated with the early winter sea ice loss in the Barents and Kara Seas
A factory fracturing model of multi-well cluster in Sulige gas field, NW China
Sulige gas field is a typical low-permeability reservoir in China. According to desert landform features along with the regional hydrologic feature and the existing fracturing technology and operational conditions, a factory-like fracturing method suitable for Sulige gas field is established to improve techniques and production organization. This method includes five key parts: (1) centralized water supply mode (water source well supply+artificial lake storage); (2) highly efficient fracturing process (two mature multi-stage fracturing technologies, sliding sleeve fracturing for vertical wells and open-hole packer fracturing for horizontal wells); (3) pipeline operation mode with seven procedures, including well drift and flushing perforation etc; (4) high efficiency operation equipment; (5) recovery of fracturing flow-back fluid. This method shortens the preparation and operation period of fracturing treatment and also relieves the pressure on environment. Pilot tests were carried out in 11 well groups in total. Sixty-seven stages of fracturing in 14 wells were successfully completed within 42 days, representing a reduction of fracturing operation cycle of more than 50%, and an encouraging improvement in efficiency. Key words: Sulige gas field, factory fracturing, big well group, water supply, fracturing process, pipeline operation, fluid recovery, high efficiency, environment friendl
Energy Performance of Hotel Buildings in Lijiang, China
The hotel industry in China has experienced rapid growth in the past ten years and made a considerable contribution to the global tourism economy. This paper focuses on the energy performance of hotel buildings in Lijiang, China. Hotel characteristics, daily operational data, and energy use data were collected by carrying out a survey of 24 hotels. The average annual energy use intensity (EUI) of four-, three-, two-, and one-star rated hotels was 180.8 kWh/m2, 113.3 kWh/m2, 74.2 kWh/m2, and 70.2 kWh/m2, respectively. Electricity, as the dominant energy source, accounted for 81% of total energy consumption and was used in the operation of air conditioning, lighting, heating, etc. Pearson correlations between EUI showed that hotel star rating, number of guest rooms, room revenue, and number of workers gave a reasonably strong correlation. A regression-based benchmarking model was established to predict EUI, and a standardization process of EUI was illustrated by statistical analysis
Analysis of the Effect of Ecosystem Services and Urbanization on Human Well-Being in Inner Mongolia Province
Ecosystem services and urbanization processes are closely related to human well-being. Understanding the interaction between the three is of great importance for sustainable development. As a case study of northern China, Inner Mongolia Province, we attempt to build an effective framework to quantify human well-being from 1995 to 2020, using the entropy method and evaluating the interaction between ecosystem services, urbanization, and human well-being through the structural equation model. This model tries to understand the interaction between the three, as well as to provide some effective policies for local conditions to improve human well-being. The results showed that: (1) Except for the value of habitat quality, carbon storage and population density fluctuated, other ecosystem services and urbanization indicators have significantly improved at the province scale from 1995 to 2020. The ecosystem services indicators revealed differences between the western and eastern regions, while the high value of urbanization indicators showed a dispersed distribution. (2) Compared with 1995, human well-being improved significantly during the last twenty-five years, during which ecological human well-being increased about 30%, economic human well-being increased about 250%, and social human well-being increased about 170%. (3) Although the path coefficients revealed that ecosystem services and urbanization can significantly promote human well-being (ecosystem service: 0.517, urbanization: 0.878), urbanization had a significantly negative effect on ecosystem services with a path coefficient of â0.608. Taking ecosystem services and urbanization into consideration when studying human well-being can not only help to quantify the effects of human activities and natural resources on human well-being, but also to understand the driving mechanisms behind them. The results indicated that identifying the effect of natural resources and human activities on human well-being is beneficial for guiding effective sustainable development policies
Industrial characteristics and drivers of urban carbon cycle: From an analysis of typical cities in China
The urban carbon cycle is an important part of the global carbon cycle. Clarifying the processes and drivers of the urban carbon cycle is essential for achieving urban carbon neutrality. Research on the urban carbon cycle under various industrial characteristics is still insufficient. In this study, four typical Chinese cities are selected and their carbon cycle processes and influencing factors are analysed. Here we propose an urban carbon neutral rate to evaluate the balance between urban carbon input and carbon output. Through Grey correlation analysis, we explore the main influencing factors of urban carbon neutral rate. The results show that the carbon neutral rate of Chinese cities is uneven and polarised. Heavy industrial cities face major challenges in urban carbon neutrality. In addition, the main factors affecting the carbon neutral rate of cities of different industrial types are not the same. The formulation of urban carbon neutral policies and measures should be differentiated and focused according to the industrial characteristics of cities
LINC01018 confers a novel tumor suppressor role in hepatocellular carcinoma through sponging microRNA-182-5p
Field test of volume fracturing for horizontal wells in Sulige tight sandstone gas reservoirs, NW China
Based on the development degree of natural micro-fractures, rock brittleness and two-direction stress and other geological conditions of the Sulige gas field, the feasibility of using volume fracturing to increase production was analyzed and verified by field test. The Sulige gas field, a typical tight sandstone gas reservoir, has developed natural micro-fractures, with fracture complex index of 0.3â0.5, rock brittleness index distribution in the 36â52 and two-direction stress heterogeneity factor of 0.17. From the development experiences of unconventional gas reservoirs abroad, the geological conditions in the Sulige gas field is suitable for volume fracturing. Through lab experiments and pilot field tests, a volume fracturing technology for horizontal wells has been developed, which features âfracturing with low-viscosity liquid, carrying proppant with high-viscosity liquid, combination of multi-scale proppants, and massive fracturing at a high injection rateâ. The technique had been applied in 42 wells of the Sulige tight gas field by the end of 2013. The initial production of wells treated by this approach is 1.2 times that of the adjacent wells treated by conventional fracturing, indicating that the technique can enhance the production of the horizontal wells in the Sulige gas field substantially. Key words: Sulige gas field, tight sandstone, volume fracturing, natural fracture, brittleness, horizontal well, microseismic monitorin