On the mechanism of ZDDP antiwear film formation

Zinc dialkyldithiophosphate additives are used to control wear and inhibit oxidation in almost all engine oils as well as many other types of lubricant. They limit wear primarily by forming a thick, protective, phosphate glass-based tribofilm on rubbing surfaces. This film formation can occur at low temperatures and is relatively indifferent to the chemical nature of the substrate. There has been considerable debate as to what drives ZDDP tribofilm formation, why it occurs only on surfaces that experience sliding and whether film formation is controlled primarily by temperature, pressure, triboemission or some other factor. This paper describes a novel approach to the problem by studying the formation of ZDDP films in full film EHD conditions from two lubricants having very different EHD friction properties. This shows that ZDDP film formation does not require solid-solid rubbing contact but is driven simply by applied shear stress, in accord with a stress-promoted thermal activation model. The shear stress present in a high pressure contact can reduce the thermal activation energy for ZDDP by at least half, greatly increasing the reaction rate. This mechanism explains the origins of many practically important features of ZDDP films; their topography, their thickness and the conditions under which they form. The insights that this study provides should prove valuable both in optimising ZDDP structure and in modelling ZDDP antiwear behaviour. The findings also highlight the importance of mechanochemistry to the behaviour of lubricant additives in general

Inequality and Internal Migration in China: Evidence from Village Panel Data

This paper analyzes the impact of rural-to-urban migration on income inequality and gender wage gap in source regions using a newly constructed panel dataset for around 100 villages over a ten-year period from 1997 to 2006 in China. Since income inequality is time-persisting, we use a system GMM framework to control for the lagged income inequality, in which contemporary emigration is also validly instrumented. We found a Kuznets (inverse U-shaped) pattern between migration and income inequality in the sending communities. Specifically, contemporary emigration increases income inequality, while lagged emigration has strong income inequalityreducing effect in the sending villages. A 50-percent increase in the lagged emigration rate translates into one-sixth to one-seventh standard deviation reduction in inequality. These effects are robust to the different specifications and different measures of inequality. More interestingly, the estimated relationship between emigration and the gender wage gap also has an inverse Ushaped pattern. Emigration tends to increase the gender wage gap initially, and then tends to decrease it in the sending villages.Internal Migration; Inequality; System GMM

Internal Migration and Income Inequality in China: Evidence from Village Panel Data

Existing studies on the impact of migration on income inequality at sending communities suffer from severe methodology defects and data limitations. This paper analyzes the impact of rural-to-urban migration on inequality using a newly constructed panel dataset for around 100 villages over a ten-year period from 1997 to 2006 in China. To our best knowledge, this is the first paper that examines the dynamic aspects of migration and income inequality employing a dynamic panel data analysis. Unlike earlier studies focusing exclusively on remittances, our data include the total labor earnings of migrants in destination areas. Furthermore, we look at the gender dimension of the impact of migration on wage inequality within the sending communities. Since income inequality is time-persisting, we use a system GMM framework to control for the lagged income inequality in estimating the effect of emigration on income inequality in the sending villages. At the same time, contemporary emigration is validly instrumented in the GMM framework because of the unobserved time-varying community shock that correlates with emigration and income inequality, as well as with the potential reverse causality from income inequality to emigration. We found a Kuznets (inverse U-shaped) pattern between migration and income inequality in the sending communities. Specifically, contemporary emigration increases income inequality, while lagged emigration has strong income inequality-reducing effect in the sending villages. A 50-percent increase in the lagged emigration rate translates into one-sixth to one-seventh standard deviation reduction in inequality. Contemporary emigration has slightly smaller effects in raising the income inequality within villages. These effects are robust to the different specifications and different measures of inequality. More interestingly, the estimated relationship between emigration and the gender wage gap also has an inverse U-shaped pattern. Emigration tends to increase the gender wage gap initially, and then tends to decrease it in the sending villages.Internal Migration; Inequality; System GMM.

Brain Drain, Brain Gain, and Economic Growth in China

This paper examines the effects of both permanent and temporary emigration on human capital formation and economic growth of the source regions. To achieve this end, this paper explores the Chinese provincial panel data from 1980 to 2005. First, the fixed effects model is employed to estimate the effect of emigration on school enrollment rates in the source regions. Relative to this aspect, we find that the magnitude (scale) of permanent emigrants (measured by the permanent emigration ratio) is conducive to the improvement of both middle and high schools enrollments. In contrast, the magnitude of temporary emigrants has a significantly positive effect on middle school enrollment but does not have a significant effect on high school enrollment. More interestingly, different educational attainments of temporary emigrants have different effects on school enrollment. Specifically, the share of temporary emigrants with high school education positively affects middle school enrollment, while the share of temporary emigrants with middle school education negatively affects high school enrollment. Second, the instrumental variable method is applied to estimate the effect of emigration on economic growth within the framework of system Generalized Method of Moments (GMM). The estimation results suggest that both permanent and temporary emigrations have a detrimental effect on the economic growth of the source regions. Our empirical tests provide some new evidence to the "brain drain" debate, which has recently received increasing attention.Brain drain, human capital, emigration, economic growth

Brain Drain, Brain Gain and Economic Growth in China

This paper examines the effects of both permanent and temporary emigration on human capital formation and economic growth of the source regions. To achieve this end, this paper explores the Chinese provincial panel data from 1980 to 2005. First, the fixed effects model is employed to estimate the effect of emigration on school enrollment rates in the source regions. Relative to this aspect, we find that the magnitude (scale) of permanent emigrants (measured by the permanent emigration ratio) is conducive to the improvement of both middle and high schools enrollments. In contrast, the magnitude of temporary emigrants has a significantly positive effect on middle school enrollment but does not have a significant effect on high school enrollment. More interestingly, different educational attainments of temporary emigrants have different effects on school enrollment. Specifically, the share of temporary emigrants with high school education positively affects middle school enrollment, while the share of temporary emigrants with middle school education negatively affects high school enrollment. Second, the instrumental variable method is applied to estimate the effect of emigration on economic growth within the framework of system Generalized Method of Moments (GMM). The estimation results suggest that both permanent and temporary emigrations have a detrimental effect on the economic growth of the source regions. Our empirical tests provide some new evidence to the "brain drain" debate, which has recently received increasing attention.Brain drain, human capital, emigration, economic growth

Strategic Public Shaming: Evidence from Chinese Antitrust

This article examines strategic public shaming, a novel form of regulatory tactic employed by the National Development and Reform Commission (NDRC) during its enforcement of the Anti-Monopoly Law. Based on analysis of media coverage and interview findings, the study finds that the way the NDRC disclosed its investigation is highly strategic depending on the firm’s co-operative attitude toward the investigation. Event studies further show that the NDRC’s proactive disclosure resulted in significantly negative abnormal returns of the stock prices of firms subject to the disclosure. For instance, Biostime, an infant-formula manufacturer investigated in 2013, experienced -22% cumulative abnormal return in a three-day event window, resulting in a loss of market capitalization that is 27 times the ultimate antitrust fine it received. The NDRC’s strategic public shaming could therefore result in severe market sanction that deters firms from defying the agency

Measuring the Economic Impact of a Road Construction Project in an Area in Japan - A Simplified Spatial Computable General Equilibrium Modeling Approach -

The study region named San-En-Nanshin region (includes Aichi, part of Nagano and Shizuoka prefecture) is considered as a model of integrated dispersed regions and taken into the National Comprehensive Development Plan of Japanese government under Regional Revitalization Project. A large scale expressway connecting north and south named San-En-Nanshin Expressway is under construction in the study region. It is expected that with the completion of the expressway, the trade, production and consumption pattern of the region will significantly be changed. Therefore this research idea is to develop a model and to test empirically the impact of distance/ commuting time after construction of San-En-Nanshin Expressway upon firm's profit maximization and households' utility maximization behavior in San-En-Nanshin region. The research aims to draw an outline of a new integrated prefectural cross-border economic model of transport, land choice and the economy at firm and household level. In later parts, this research also intends to draw the location choice behavior and corresponding market equilibrium conditions based on transportation demand. As the results, combining this model and the short cut method for the evaluation of economic benefit of a transportation project under the general equilibrium framework, the total annual benefit after construction of San-En-Nanshin Expressway was estimated as 24.3 billion yen, at which 6.3 billion yen for business objective and 18 billion yen for leisure objective. The economic impact of San-En-Nanshin Expressway on Hamamatsu, Nanshin is largest as about 9.7 billion yen. Mito, Otawa, Ichinomiya, Tsukude get little impact. The total project cost of San-En-Nanshin Expressway is estimated as 500 billion yen or 1 trillion yen. If the project cost is about 500 billion yen, the construction of San-En-Nanshin Expressway passes the cost benefit criteria. In case of project cost of 1 trillion yen, this project is rejected under the cost-benefit principle. In this case, one must consider the way of increasing the benefit of the expressway by promotion of economic resource endowment in the sense of quality.