8,162 research outputs found

    Estimating the Impacts of Climate Change on Mortality in OECD Countries

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    The major contribution of this study is to combines both climatic and macroeconomic factors simultaneously in the estimation of mortality using the capital city of 22 OECD countries from the period 1990 to 2008. The empirical results provide strong evidences that higher income and a lower unemployment rate could reduce mortality rates, while the increases in precipitation and temperature variation have significantly positive impacts on the mortality rates. The effects of changing average temperature on mortality rates in summer and winter are asymmetrical and also depend on the location. Combining the future climate change scenarios with the estimation outcomes show that mortality rates in OECD countries in 2100 will be increased by 3.77% to 5.89%.Climate change; mortality; panel data model

    Modeling the Effect of Oil Price on Global Fertilizer Prices

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    The main purpose of this paper is to evaluate the effect of crude oil price on global fertilizer prices in both the mean and volatility. The endogenous structural breakpoint unit root test, the autoregressive distributed lag (ARDL) model, and alternative volatility models, including the generalized autoregressive conditional heteroskedasticity (GARCH) model, Exponential GARCH (EGARCH) model, and GJR model, are used to investigate the relationship between crude oil price and six global fertilizer prices. Weekly data for 2003-2008 for the seven price series are analyzed. The empirical results from ARDL show that most fertilizer prices are significantly affected by the crude oil price, which explains why global fertilizer prices reached a peak in 2008. We also find that that the volatility of global fertilizer prices and crude oil price from March to December 2008 are higher than in other periods, and that the peak crude oil price caused greater volatility in the crude oil price and global fertilizer prices. As volatility invokes financial risk, the relationship between oil price and global fertilizer prices and their associated volatility is important for public policy relating to the development of optimal energy use, global agricultural production, and financial integration.Volatility; Global fertilizer price; Crude oil price; Non-renewable fertilizers; Structural breakpoint unit root test

    On Hadronic Production of the BcB_c Meson

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    Two of the approaches to the hadronic productions of the double heavy mesons BcB_c and Bc∗B_c^* are investigated. Comparison in various aspects on the results obtained by the approaches is made and shown in figures and a table. Some trial understanding of the approaches themselves and the achieved results is presented. The results may be used as some references for discovering the mesons at Tevatron and LHC.Comment: 18 pages, the revised version of hep-ph/940824

    Reliability of a Maintainable Manufacturing Network subject to Budget

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    Applying network analysis, a manufacturing system can be constructed as a manufacturing network by representing each workstation as an arc and each inspection station as a node. In particular, the capacity of each workstation is stochastic (i.e. multistate) due to the possibility of failure, partial failure, and maintenance. In practical cases, such a manufacturing network has to achieve a specified production level to satisfy the customers’ orders. Hence, maintenance is necessary to guarantee a manufacturing network can retain a minimal production level. A maintenance model, namely maintainable manufacturing network (MMN), is proposed to evaluate whether the manufacturing system can provide sufficient capacity subject to maintenance budget or not. The maintenance reliability is further proposed to calculate the probability that the MMN provides a sufficient capacity level to meet the minimal production level under maintenance budget

    Wettability Alteration Process at Pore-Scale during Engineered Waterflooding using Computational Fluid Dynamics

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    Engineered waterflooding modifies chemistry of injected brine to efficiently and environmentally friendly enhance oil recovery. The common practice of engineered waterflooding includes low salinity waterflooding (LSW) and carbonated waterflooding. Among these oil recovery methods, wettability alteration has been perceived as a critical physicochemical process for additional oil recovery. While extensive work has been conducted to characterize the wettability alteration, the existing theory cannot explain the conflict oil recovery between secondary mode (injecting engineered water at the very beginning of flooding) and tertiary mode (injecting engineered water after conventional waterflooding), where secondary engineered waterflooding always gives a greater incremental oil recovery than tertiary mode. To explain this recovery difference, a preferential flow channel was hypothesized to be created by secondary flooding, which likely reduces sweep efficiency of tertiary flooding. To test this hypothesis, computational fluid dynamic simulations were performed with finite volume method coupled with dynamic contact angles in OpenFOAM to represent wettability characteristics (from strongly oil-wet to strongly water-wet) at pore scale to quantify the role of pre-existing flow channel in the oil recovery at different flooding modes. The simulation results showed that secondary engineered waterflooding indeed generates a preferential flow pathway, which reduces recovery efficiency of subsequent tertiary waterflooding. Streamline analysis confirms that tertiary engineered waterflooding transports faster than secondary engineered waterflooding, implying that sweep efficiency of tertiary engineered waterflooding is lower than secondary engineered waterflooding. This work provides insights for a greater oil recovery at secondary mode than tertiary mode during engineered waterflooding at pore scale
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