Polluting emissions and GDP : decoupling evidence from brazilian states

We provide a comprehensive analysis of the relationship between greenhouse gas (GHG) emissions and GDP in Brazil using both aggregate and state-level data. The trend or Kuznets elasticity is about 0.8 for Brazil, higher than that in advanced countries but below that of major emerging markets. The elasticity is somewhat higher for consumption-based emissions than for production-based emissions, providing evidence against the “pollution haven” hypothesis. Additional evidence comes from state-level data analysis where one can observe a great deal of heterogeneity but also some hope as far as decoupling is concerned. In addition to the trend relationship between emissions and output, we find that there does not seem to exist a cyclical relationship holding in Brazil at the aggregate level (despite having become more procyclical over time), but it does exist in a few states.info:eu-repo/semantics/publishedVersio

The Effects of Loss Aversion on Trade Policy and the Anti-Trade Bias Puzzle

We study the implications of loss aversion for trade policy determination and show how it allows us to explain a number of important and puzzling features of trade policy. In particular, we show that if individual preferences exhibit loss aversion and the coefficient of loss aversion is large enough, there will be an anti-trade bias in trade policy. We also show that, for a sufficiently high coefficient of loss aversion, more import-competing lobbies will form than under the current leading political economy model of trade protection due to Grossman and Helpman (1994), and import-competing sectors will be more likely to form a lobby than export sectors, reinforcing the anti-trade bias result. The predictions for protection that we obtain also imply that, everything else equal, higher protection will be given to those sectors in which profitability is declining. We use a nonlinear regression procedure to directly estimate the parameters of the model and test the empirical validity of its predictions. We find empirical support for the model and, very importantly, we obtain estimates of the parameters that are very close to those estimated by Kahneman and Tversky (1992) using experimental data. In order to test some predictions on the lobbying side, we estimate a Probit equation on political organization using the two-stage conditional maximum likelihood estimator proposed by Rivers and Vuong (1988), and find evidence of loss aversion in lobby formation. Finally but importantly, we find that the data favors our model over the Grossman and Helpman modelTrade policy, anti-trade bias, loss aversion

Design for Additive Manufacturing of Conformal Cooling Channels Using Thermal-Fluid Topology Optimization and Application in Injection Molds

Additive manufacturing allows the fabrication parts and tools of high complexity. This capability challenges traditional guidelines in the design of conformal cooling systems in heat exchangers, injection molds, and other parts and tools. Innovative design methods, such as network-based approaches, lattice structures, and structural topology optimization have been used to generate complex and highly efficient cooling systems; however, methods that incorporate coupled thermal and fluid analysis remain scarce. This paper introduces a coupled thermal-fluid topology optimization algorithm for the design of conformal cooling channels. With this method, the channel position problem is replaced to a material distribution problem. The material distribution directly depends on the effect of flow resistance, heat conduction, as well as forced and natural convection. The problem is formulated based on a coupling of Navier-Stokes equations and convection-diffusion equation. The problem is solved by gradient-based optimization after analytical sensitivity derived using the adjoint method. The algorithm leads a two -dimensional conceptual design having optimal heat transfer and balanced flow. The conceptual design is converted to three-dimensional channels and mapped to a morphological surface conformal to the injected part. The method is applied to design an optimal conformal cooling for a real three dimensional injection mold. The feasibility of the final designs is verified through simulations. The final designs can be exported as both three-dimensional graphic and surface mesh CAD format, bringing the manufacture department the convenience to run the tool path for final fitting

Multiscale, thermomechanical topology optimization of self-supporting cellular structures for porous injection molds

Purpose This paper aims to establish a multiscale topology optimization method for the optimal design of non-periodic, self-supporting cellular structures subjected to thermo-mechanical loads. The result is a hierarchically complex design that is thermally efficient, mechanically stable and suitable for additive manufacturing (AM). Design/methodology/approach The proposed method seeks to maximize thermo-mechanical performance at the macroscale in a conceptual design while obtaining maximum shear modulus for each unit cell at the mesoscale. Then, the macroscale performance is re-estimated, and the mesoscale design is updated until the macroscale performance is satisfied. Findings A two-dimensional Messerschmitt Bolkow Bolhm (MBB) beam withstanding thermo-mechanical load is presented to illustrate the proposed design method. Furthermore, the method is implemented to optimize a three-dimensional injection mold, which is successfully prototyped using 420 stainless steel infiltrated with bronze. Originality/value By developing a computationally efficient and manufacturing friendly inverse homogenization approach, the novel multiscale design could generate porous molds which can save up to 30 per cent material compared to their solid counterpart without decreasing thermo-mechanical performance. Practical implications This study is a useful tool for the designer in molding industries to reduce the cost of the injection mold and take full advantage of AM

Does democracy foster or hinder growth? Extreme-type political regimes in a large panel

Using a panel dataset of 86 countries from 1960-2005, this paper empirically assesses the effect of several democracy proxies (by means of the Polity IV database), together with a set of control variables, such as human capital and the initial level of GDP per capita, on the rate of economic growth. By means of pooled OLS regressions, fixed effects and TSLS estimation procedures our results support the long-run conditional convergence hypothesis and they show a positive and statistically significant effect of democracy and human capital on economic growth. Furthermore, these findings are robust to several sensitivity exercises, such as the consideration of different time spans and groupings (rich and poor countries). Our evaluation allows us to conclude that electoral democracy, by itself, increases GDP growth per capita while almost no support is found for the hypothesis that autocracy, by itself, increases it.endogeneity, autocracy, human capital, convergence, Polity-IV

Empirical Applications of Neoclassical Growth Models the "Fit" of the Solow Augmented Growth Model

The theories of country growth models are supported by the high scale variation observed in these countries’ growth rates. This is the reason behind those typical questions, like “Why did some East Asian countries grow so much?”, amongst others. Therefore, a lot of recent research has been focused in trying to explain why some countries are richer than others, using, for example, the human capital-augmented Solow Swan model of dispersion in income levels. The article by Mankiw, Romer and Weil [1992] contains a thorough empirical analysis of this type of Solow model augmented with human capital, based on version Penn World Table (ab hinc PWT) 4.0 of the famous Summers and Heston dataset. In this paper I apply a similar analysis to the augmented Solow model as presented in Jones [2002], Chapter 3. Like the augmented Solow model of Mankiw, Jones’ model has the basic Solow model as a special case. Using a more recent version PWT 5.6 of the Summers and Heston dataset, updated until 1997 and with the variable referring to the fraction of time individuals spend on learning new skills added, this paper aims to perform a new and revisited level and convergence analysis of both the (un)restricted basic and augmented Solow-Swan Model.

On the performance of US fiscal forecasts : government vs. private information

This paper contributes to shed light on the quality and performance of US fiscal forecasts. The first part inspects the causes of official (CBO) fiscal forecasts revisions between 1984 and 2016 that are due to technical, economic or policy reasons. Both individual and cumulative means of forecast errors are relatively close to zero, particularly in the case of expenditures. CBO averages indicate net average downward revenue and expenditure revisions and net average upward deficit revisions. Focusing on the causes of the technical component, we uncover that its revisions are quite unpredictable which casts doubts on inferences about fiscal policy sustainability that rely on point estimates. Comparing official with private-sector (Consensus) forecasts, despite the informational advantages CBO might have, one cannot unequivocally say that one or the other is more accurate. Evidence also seems to suggest that CBO forecasts are consistently heavily biased towards optimism while this is less the case for Consensus forecasts. Not only is the extent of information rigidity is more prevalent in CBO forecasts, but evidence also seems to indicate that Consensus forecasts dominate CBO’s in terms of information content.info:eu-repo/semantics/publishedVersio

Searching force-closure optimal grasps of articulated 2D objects with n links

This paper proposes a method that finds a locally optimal grasp of an articulated 2D object with n links considering frictionless contacts. The surface of each link of the object is represented by a finite set of points, thus it may have any shape. The proposed approach finds, first, an initial force-closure grasp and from it starts an iterative search of a local optimum grasp. The quality measure considered in this work is the largest perturbation wrench that a grasp can resist with independence of the direction of the perturbation. The approach has been implemented and some illustrative examples are included in the article.Postprint (published version

Mechanical properties and energy absorbing capabilities of Z-pinned aluminum foam sandwich

Aluminum foam sandwich (AFS) structures are suitable for impact protection in lightweight structural components due to their specific energy absorption capability under compression. However, tailoring the deformation patterns of the foam cells is a difficult task due to the randomness of their internal architecture. The objective of this study is to analyze the effect of embedding aluminum pins into an AFS panel (Z-pinning) to better control its deformation pattern and improve its energy absorption capability. This study considers a closed-cell AFS panel and analyzes the effect of multi-pin layout parallel to the direction of the uniaxial compressive loading. The results of the experimental tests on the reference (without Z-pinning) AFS are utilized to develop numerical models for the reference and Z-pinned AFS structures. Physical experiments and numerical simulations are carried out to demonstrate the advantages of Z-pinning with aluminum pins. The results exhibit a significant increase in elastic modulus, plateau stress and energy absorption capability of the Z-pinned samples. Also, the effect of the pin size and Z-pinning layout on the mechanical performance of the Z-pinned AFS is also investigated using numerical simulations