From Predators to Icons: Exposing the Myth of the Business Hero

[ Excerpted from Forword by John R. Kimberly] From Predators to Icons takes us on a provocative and nuanced journey through the business practices of a number of individuals and the companies they built and shows how they navigated through this volatile mix to achieve extraordinary success in their undertakings. In an era in which we are obsessed with rankings of everything from colleges and universities to hospitals to tennis players, we tend to focus on the end result—who is number 1?—and much less on the means: how did they get there? In an era when we are fascinated by stories of leaders as heroes and by the lives of the rich and famous, we tend to let the gloss of the material trappings of success blind us to questions of their origins. In the work they report here, Villette and Vuillermot use the lens of social science as a vehicle for unpacking the roots of extraordinary success in business, for analyzing how success was achieved. They have accumulated evidence from a variety of sources, including the myriad biographies—authorized and unauthorized—of business icons, to build their comparative analysis of the practices of thirty-two businessmen from Europe and North America, of how their wealth was built, and of the common threads that characterize the roots of success across geographies, across industries, and across time. Their approach is highly original, and the data they assemble are wide-ranging. They are well aware of both the promise and the limitations of their data and are careful to discuss both. Ultimately, it is up to each of us to judge the credibility of both the empirical foundations on which their analysis is built and the conclusions they reach, the messages they send. But theirs is an impressive undertaking and needs to be taken seriously

Optimal rates of convergence for persistence diagrams in Topological Data Analysis

Computational topology has recently known an important development toward data analysis, giving birth to the field of topological data analysis. Topological persistence, or persistent homology, appears as a fundamental tool in this field. In this paper, we study topological persistence in general metric spaces, with a statistical approach. We show that the use of persistent homology can be naturally considered in general statistical frameworks and persistence diagrams can be used as statistics with interesting convergence properties. Some numerical experiments are performed in various contexts to illustrate our results

On the Potential of Foreign Aid as Insurance

In this paper, we argue that it would be fruitful to revisit foreign aid's potential as an insurance mechanism against macroeconomic shocks. In a simple model of aid flows between two endowment economies, we show that at least three fourths of the large welfare costs of macroeconomic fluctuations in poor countries could be alleviated by a simple reallocation of aid flows across time.Foreign aid, Consumption smoothing, Macroeconomic fluctuations, Welfare

The Potential of Foreign Aid as Insurance

This paper quantifies the potential of foreign aid as an insurance mechanism against macroeconomic shocks. Within a dynamic model of aid flows between two endowment economies, we show that at least three-fourths of the large welfare costs of macroeconomic fluctuations in poor countries could be alleviated by a simple reallocation of aid flows across time. In developing countries subject to persistent macroeconomic shocks, the resulting welfare improvement is of first-order magnitude. Copyright 2006, International Monetary Fund

Calcium phosphate precipitation modeling in a pellet reactor

The calcium phosphate precipitation in a pellet reactor can be evaluated by two main parameters: the phosphate conversion ratio and the phosphate removal efficiency. The conversion ratio depends mainly on the pH. The pellet reactor efficiency depends not only on pH but also on the hydrodynamical conditions. An efficiency model based on a thermochemical precipitation approach and an orthokinetic aggregation model is presented. In this paper, the results show that optimal conditions for pellet reactor efficiency can be obtained

SPH method applied to high speed cutting modelling

The purpose of this study is to introduce a new approach of high speed cutting numerical modelling. A Lagrangian smoothed particle hydrodynamics (SPH)- based model is arried out using the Ls-Dyna software. SPH is a meshless method, thus large material distortions that occur in the cutting problem are easily managed and SPH contact control permits a "natural" workpiece/chip separation. The developed approach is compared to machining dedicated code results and experimental data. The SPH cutting model has proved is ability to account for continuous to shear localized chip formation and also correctly estimates the cutting forces, as illustrated in some orthogonal cutting examples. Thus, comparable results to machining dedicated codes are obtained without introducing any adjusting numerical parameters (friction coefficient, fracture control parameter)

A predictive fatigue life model for anodized 7050 aluminium alloy

The objective of this study is to predict fatigue life of anodized 7050 aluminum alloy specimens. In the case of anodized 7050-T7451 alloy, fractographic observations of fatigue tested specimens showed that pickling pits were the predominant sites for crack nucleation and subsequent failure. It has been shown that fatigue failure was favored by the presence of multiple cracks. From these experimental results, a fatigue life predictive model has been developed including multi-site crack consideration, coalescence between neighboring cracks, a short crack growth stage and a long crack propagation stage. In this model, all pickling pits are considered as potential initial flaws from which short cracks could nucleate if stress conditions allow. This model is built from experimental topography measurements of pickled surfaces which allowed to detect the pits and to characterize their sizes (depth, length, width). From depth crack propagation point of view, the pickling pits are considered as stress concentrator during the only short crack growth stage. From surface crack propagation point of view, machining roughness is equally considered as stress concentrator and its influence is taken into account during the all propagation stage. The predictive model results have been compared to experimental fatigue data obtained for anodized 7050-T7451 specimens. Predictions and experimental results are in good agreement

Surface characterization and influence of anodizing process on fatigue life of Al 7050 alloy

The present study investigates the influence of anodizing process on fatigue life of aluminium alloy 7050-T7451 by performing axial fatigue tests at stress ratio ‘R’ of 0.1. Effects of pre-treatments like degreasing and pickling employed prior to anodizing on fatigue life were studied. The post-exposure surface observations were made by scanning electron microscope (SEM) to characterize the effect of each treatment before fatigue testing. The surface observations have revealed that degreasing did not change the surface topography while pickling solution resulted in the formation of pits at the surface. Energy dispersive spectroscopy (EDS) was used to identify those constituent particles which were responsible for the pits formation. These pits are of primary concern with respect to accelerated fatigue crack initiation and subsequent anodic coating formation. The fatigue test results have shown that pickling process was detrimental in reducing the fatigue life significantly while less decrease has been observed for anodized specimens. Analyses of fracture surfaces of pickled specimens have revealed that the process completely changed the crack initiation mechanisms as compared to non-treated specimens and the crack initiation started at the pits. For most of the anodized specimens, fatigue cracks still initiated at the pits with very few cracks initiated from anodic coating. The decrease in fatigue life for pickled and anodized specimens as compared to bare condition has been attributed to decrease in initiation period and multi-site crack initiations. Multi-site crack initiation has resulted in rougher fractured surfaces for the pickled and anodized specimens as compare to bare specimens tested at same stress levels

A thermochemical approach for calcium phosphate precipitation modeling in a pellet reactor

A common pathway for P-recovery from wastewater is phosphate precipitation as calcium phosphates. In this paper, a thermodynamic model for phosphate precipitation is proposed based on various models of activity coefficients taking into account various calcium phosphate phases which can crystallize in the range of pH to be considered, i.e. both dicalcium phosphate dihydrate (DCPD) and amorphous calcium phosphate (ACP) for pH lower than 7.3 and only ACP for pH higher than 7.3. The parameters include the solubility products of ACP and DCPD species. The observed discrepancy in liquid phase equilibrium constants reported in the literature leads to determination of an uncertainty zone describing the precipitation domain. The results obtained offer interesting possibilities for a further optimization of process operating conditions, i.e. determining Ca/P molar ratio, in order to reduce effluent pH (thus avoiding post-treatment) and, consequently, to maximize reactor efficiency