698 research outputs found
Tax Structure and Corruption: Cross-Country Evidence
The determinants of corruption have long been an important subject for research in the elds of economics and political science. The literature has identi ed a wide range of factors that cause corruption; however, little research has been done on how the design of government policy in uences corruption. We advance a new factor, the tax structure being measured as both tax mix and tax complexity, as another potential cause of corruption, and present strong supporting evidence by using a large sample of countries over the period 1995-2009. Our ndings indicate that: (1) countries relying more heavily on direct taxes tend to enjoy a lower level of corruption, as opposed to countries with higher reliance on indirect taxes; and (2) countries with more complex tax systems tend to have a higher level of corruption, as opposed to countries with less complex tax systems. These results are robust across alternative measures of corruption and tax structure, and alternative estimations with and without correcting the potential endogeneity issue of the tax structure variables
Multiple positive solutions to the fractional Kirchhoff problem with critical indefinite nonlinearities
This article concerns the existence and multiplicity of positive solutions to the fractional Kirchhoff equation with critical indefinite nonlinearities by applying the Nehari manifold approach and fibering maps
A Practical, Direct Approach for Fusion of Tool Size Measurement and Flank Wear Prediction of End-Mills in Machining
On-machine measurement (OMM) of cutting tools is to automatically and directly measure them for length and diameter in machining breaks and compensated tool paths in the following machining. Tool condition monitoring (TCM) is to automatically predict tool wear and detect tool failure in machining, which is often evaluated with the width of flank wear land. OMM of cutting tools is widely applied with tool setters in the industry, however, it cannot measure flank wear to monitor tool conditions and predict the tool life. To address the problem in this research, an approach for fusion of tool size measurement and flank wear prediction of end-mills is proposed. First, the model of a fillet end-mill is built. Design principles are studied based on practical machining, which include the smoothness of the end-mill’s flank face, and the relief angle of the fillet cutting edge. Second, the model of an indexable face mill is also built accurately. Third, the geometric relationship between tool radius and flank wear land width is established for the indexable face mill. Then, an experimental method is adopted to optimize measurement locations. At last, experiments are conducted that the end-mill is measured at the locations, and the tool radius is used to calculate the flank wear width. The results show the proposed approach is effective for tool condition monitoring. This research successfully develops the OMM-TCM fusion technology and benefits the manufacturing industry
Where to focus? Developing a LCA impact category selection tool for manufacturers of building materials
Life cycle assessment (LCA) has been widely applied to improve the environmental performance of the building sector. However, due to the complexity of LCA results including the multitude of impact categories, decision makers of the building materials manufacturing industry are grappling with allocating their limited resources to the most influential impact categories. The aim of this article, therefore, is to propose an impact category selection tool that enables performance improvement of building materials without sacrificing the validity of LCA results. The developed method selects common building materials, and defines foreground processes that can be influenced by manufacturers of building materials and background processes that can hardly be impacted using the US Input-Output database. Following the life cycle impact assessment (LCIA) analysis with the ReCiPe2016 Midpoint method, our results indicate that, among the 18 impact categories of the ReCiPe2016 Midpoint method, Global Warming Potential, Ozone Formation and Human Health, Fine Particulate Matter Formation, Ozone Formation and Terrestrial Ecosystems, Terrestrial Acidification, and Terrestrial Ecotoxicity should be considered the first priority group while Ionizing Radiation, Freshwater Eutrophication, Marine Eutrophication, Freshwater Ecotoxicity, Water Consumption should be placed in the last priority group. It further suggests that by shifting the limited available resources to the first priority group, decision makers can readily improve the environmental performance of building materials during the manufacturing process. The contribution of the proposed selection tool lies in that it can be adapted by decision makers to different geographical contexts, LCIA methods, and building materials to efficiently ameliorate the environmental performance of the building sector
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