The Impact of Virtuality and Shared Leadership on Virtual Team Performance

Previous studies show divergent views of shared leadership in the team performance of virtual teams. In this study, we seek to understand the mediating and moderating roles of trust, commitment, and virtuality among virtual team members on performance within the context of shared leadership. We conducted a questionnaire-based survey to gather perspectives on shared leadership and performance and analysed responses through structural equation modelling. We find that there is a significant positive effect between the two and that virtuality plays a significant moderating role for virtual team performance. In addition, we find that when virtuality increases, the mediating effect of trust and commitment is not significant, which challenges previous findings

A Case Study on Foamy Oil Characteristics of the Orinoco Belt, Venezuela

With a current recovery of less than 11%, the Orinoco Belt in Venezuela still contains potentially more than 1.3 trillion barrels of reserves of “three highs, one low” oil at a depth of 100 to 1500 m. 5 joint projects and one project of Petroleos de Venezuela SA are making plans to improve oil recovery in the area. So it is important for them to have a thorough knowledge of foamy oil characteristics. This reservoir has a peculiar behavior called as a foamy phenomenon. In order to characterize the properties of the foamy oil, this paper discussed unconventional test methodology and the detailed suite of laboratory procedures including PVT and pressure depletion tests used to examine the Orinoco heavy oil. The results showed substantial differences in characteristics of foamy oil and conventional oil studied, not only in terms of PVT behavior but also in terms of the production performance during pressure depletion tests. The foamy oil compressibility was between 10-120×10-4 mPa-1, which was obviously higher than that of conventional oil. Differential liberation experiments of the oil, with obvious high formation volume factor, stable GOR, and low density showed a strong tendency to foam below the bubble point. Other notable observations were that more efficient oil recovery was achieved at high depletion rates while less free gas was produced.Key words: Foamy oil; Unconventional tests; The Orinoco Belt; PVT; Pressure depletion test

Dynamic Lidar Ratio Calculation and Aerosol Vertical Extinction Coefficient Retrieval Based on Observed Visibility

Micropulse lidar (MPL) cannot directly retrieve the aerosol extinction coefficient under cloudy conditions and at night. Therefore, we used ground visibility, Fernald’s near-end solution method, and the linear correlation between the near-end lidar signal (photons) and ground aerosol extinction coefficient (correlation coefficient = 0.98), to calculate the lidar constant and lidar ratio (LR). We compared the aerosol optical depth (AOD) retrieved from MPL and the AOD retrieved from the multifilter rotating shadowband radiometer (MFRSR-7) at the same band (532 nm). The correlation coefficient was 0.77. The vertical distribution of aerosols in daytime and nighttime during summer was obtained from lidar in July at 00:00 and 12:00 Beijing time (UTC+8). In daytime, under clear sky conditions, the distribution displayed a unimodal and peak at approximately 2000 m. The distribution at night was more complicated than that in the day, with three results. The first was monotonically decreasing from ground to upper layer, with a peak at 600 m and two peaks at approximately 1200 m. In general, the aerosol extinction coefficient at nighttime is higher than that at daytime below 1200 m. The near-ground extinction coefficient at night is higher than in the day