Entrepreneurship and Growth: Evidence from China

This paper examines the impact of entrepreneurship on economic growth by using a panel data set of 29 provinces in China over 20 years. Two indicators of entrepreneurship are defined and introduced into the traditional growth regression framework that is estimated using the system generalized method of moments. We also use the ratio of staff and workers of state-owned enterprises and per capita sown land area as the instrumental variables to identify the causal effect of entrepreneurship on economic growth. Our results suggest that entrepreneurship has a significant positive effect on economic growth and this finding is robust even after we control for other demographic and institutional variables. Our study provides some evidence that may be used as a basis for evaluating the effect of China’s policy on private business which has been increasingly relaxed since the late 1970s.

Vortex break-down during the impact of a starting subsonic compressible gas jet on a multi-plume spray

The final publication is available at Springer via https://dx.doi.org/10.1007/s12650-016-0345-yThe impact process and the consequent two-phase interaction for a compressible subsonic starting gas jet colliding on a multi-plume spray are investigated using large eddy simulation with Eulerian/Lagrangian multiphase approach, and the λ 2 criterion is used to visualize the temporal and spatial evolution of the vortical structures in the gas field. It is shown that before the impact a leading tip vortex ring is followed by smaller vortex rings in the quasi-steady region of the starting jet while the vortical structures inside the spray plumes known as spray-induced air jets are formed. After the impact the leading tip vortex ring and the following rings as well as spray-induced air jet vortices start to deform and eventually break down into smaller elongated vortex filaments. Unlike the injection of multi-plume sprays into the core of a steady cross flow gas jet, spray droplets are dispersed in a larger volume in all directions when impacted by the starting gas jet, beneficial for two-phase mixing enhancement. A pair of vortex rings is also observed merging into a new ring before reaching the impact zone.Graphical abstract Open image in new windowNatural Sciences and Engineering Research Council of Canada ["Discovery Grant"

Assessment and validation of liquid breakup models for high-pressure dense diesel sprays

The final publication is available at Springer via https://dx.doi.org/10.1007/s11708-016-0407-9Liquid breakup in fuel spray and atomization significantly affects the consequent mixture formation, combustion behavior, and emission formation processes in a direct injection diesel engine. In this paper, different models for liquid breakup processes in high-pressure dense diesel sprays and its impact on multi-dimensional diesel engine simulation have been evaluated against experimental observations, along with the influence of the liquid breakup models and the sensitivity of model parameters on diesel sprays and diesel engine simulations. It is found that the modified Kelvin-Helmholtz (KH)–Rayleigh-Taylor (RT) breakup model gives the most reasonable predicted results in both engine simulation and high-pressure diesel spray simulation. For the standard KH-RT model, the model constant C bl for the breakup length has a significant effect on the predictability of the model, and a fixed value of the constant C bl cannot provide a satisfactory result for different operation conditions. The Taylor-analogybreakup (TAB) based models and the RT model do not provide reasonable predictions for the characteristics of high-pressure sprays and simulated engine performance and emissions.Ontario Research Fund-Research Excellence (ORF-RE) program # RE-02-019]Natural Sciences and Engineering Research Council of Canada (NSERC) via a Discovery Gran

A modeling and experimental study of capacity fade for lithium-ion batteries

Lithium-ion batteries are extensively used in electric vehicles, however, their significant degradation over discharge and charge cycles results in severe capacity fade, limiting driving ranges of electric vehicles over time and useful lifetime of batteries. In this study, capacity fade for lithium-ion battery has been investigated through modeling and experiment. A predictive model is developed based on first principles incorporating degradation mechanisms. The mechanisms of degradation considered include solid-electrolyte interface (SEI) growth and active material loss at both negative and positive electrodes. Battery performance including capacity is measured experimentally under discharge and charge cycling with battery operation temperature controlled. It is shown that battery capacity is reduced over battery discharge/charge cycling at a given battery operation temperature, and the model predicted battery performance, including capacity fade, agrees well with the experimental results. As the number of discharge/charge cycles are increased, battery capacity is reduced significantly; battery capacity fade is increased substantially when battery operation temperature is increased, indicating significantly accelerated aging of the battery at elevated operation temperatures and hence the importance of battery thermal management in the control of battery operation temperature for practical applications such as electric vehicles. Battery capacity fade is mainly caused by SEI film growth at the negative electrode, which is the largest contributing factor to the capacity fade, and the active material isolation at the negative electrode, which is the second largest influencing aging factor.Natural Sciences and Engineering Research Council of Canada || Dana Canada Corporatio

Synthesis Of Diamond-Like Carbon By Pecvd On Different Substrates For Fuel Cell Applications

Lower cost, lighter weight, and higher electrical conductivity are among many advantages of using metallic bipolar plates (BPs) over the conventional graphitic materials in PEM fuel cell applications. In this study, diamond-like carbon (DLC) coatings are deposited on top surfaces of stainless steel (SS316) and Aluminum (Al5052) substrates via Plasma Enhanced Carbon Vapor Deposition (PECVD) in order to increase the durability. Further, the effect of different plasma power intensities and type of precursor gases, including methane (CH4) and acetylene (C2H2), on the growth of DLC films is studied. Various ex-situ characterization techniques have been used to examine the strength of adhesion, morphologies, structures/compositions, and wettability of the DLC coatings. It is found that coatings produced from CH4 gas show superior adhesion in comparison to those obtained from the C2H2 gas. Results indicate that higher deposition power intensity can produce more sp3 bonds than sp2 bonds. It is also determined that the type of the metallic substrates has predominant roles on the morphology of the DLC coatings. In addition, a moderate power intensity of 250 W results in desirable properties in DLC, including adhesion and wettability, compared to higher and lower plasma power intensities

Changes in three tumor markers in patients with advanced lung adenocarcinoma after combination therapy with pemetrexed and platinum: Short-term treatment efficacy

Purpose: To study changes in three tumor markers before and after combination treatment with pemetrexed and platinum, and evaluate the short-term therapeutic effectiveness of the treatment in advanced lung adenocarcinoma (ALA) subjects. Method: Patients with ALA (n =120) admitted to JinHua Municipal Central Hospital from January 2017 to May 2018 were selected as the research subjects. According to the results of chemotherapy, they were divided into two groups: significantly-reduced tumor volume group (90 cases), and nonsignificantly-reduced tumor volume group (21 cases). The two groups were treated with chemotherapy using a combination of pemetrexed and cisplatin. The levels of CEA, CA125 and CYFRA21-1 before and after chemotherapy were assayed to determine their relationship with short-term therapy effectiveness. Result: Overall analysis of tumor markers in the 120 patients with ALA showed statistically significant reduction in overall tumor marker levels before and after chemotherapy (p < 0.05). At the end of chemotherapy, the tumor markers were markedly reduced in subjects with significant tumor volume, and there was statistical difference between the two groups before chemotherapy (p < 0.05). Changes in CEA, CA125 and CYFRA21-1 were positively correlated with the chemotherapeutic effects on patients with ALA. Conclusion: In ALA patients treated with pemetrexed and platinum, changes in serum CEA, CA125 and CYFRA21-1 profiles before and after treatment depend on the effect of chemotherapy, and they are reliable for prediction of short-term therapeutic efficacy