Reference-free evaluation of thin films mass thickness and composition through energy dispersive x-ray spectroscopy

In this paper we report the development of a new method for the evaluation of thin films mass thickness and composition based on the Energy Dispersive X-Ray Spectroscopy (EDS). The method exploits the theoretical calculation of the in-depth characteristic X-ray generation distribution function, $\phi$/($\rho$ z), in multilayer samples, obtained by the numerical solution of the electron transport equation, to achieve reliable measurements without the need of a reference sample and multiple voltages acquisitions. The electron transport model is derived from the Boltzmann transport equation and it exploits the most updated and reliable physical parameters in order to obtain an accurate description of the phenomenon. The method for the calculation of film mass thickness and composition is validated with benchmarks from standard techniques. In addition, a model uncertainty and sensitivity analysis is carried out and it indicates that the mass thickness accuracy is in the order of 10 $\mu$g/cm$^2$, which is comparable to the nuclear standard techniques resolution. We show the technique peculiarities in one example measurement: two-dimensional mass thickness and composition profiles are obtained for a ultra-low density, high roughness, nanostructured film.Comment: This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (ENSURE grant agreement No. 647554

A Hu–Washizu variational approach to self-stabilized virtual elements: 2D linear elastostatics

An original, variational formulation of the Virtual Element Method (VEM) is proposed, based on a Hu–Washizu mixed variational statement for 2D linear elastostatics. The proposed variational framework appears to be ideal for the formulation of VEs, whereby compatibility is enforced in a weak sense and the strain model can be prescribed a priori, independently of the unknown displacement model. It is shown how the ensuing freedom in the definition of the strain model can be conveniently exploited for the formulation of self-stabilized and possibly locking-free low order VEs. The superior performances of the VEs formulated within this framework has been verified by application to several numerical tests

Faraway, so Close: Coupled Climate and Economic Dynamics in an Agent-Based Integrated Assessment Model

In this work we develop an agent-based model that offers an alternative to standard, computable general equilibrium integrated assessment models (IAMs). The Dystopian Schumpeter meeting Keynes (DSK) model is composed of heterogeneous firms belonging to capital-good, consumption-good and energy sectors. Production and energy generation lead to greenhouse gas emissions, which affect temperature dynamics. Climate damages are modelled at the individual level as stochastic shocks hitting workers' labour productivity, energy efficiency, capital stock and inventories of firms. In that, aggregate damages emerge from the aggregation of losses suffered by heterogeneous, interacting and boundedly rational agents. The model is run focusing on a business-as-usual carbon-intensive scenario consistent with a Representative Concentration Pathway 8.5. We find that the DSK model is able to account for a wide ensemble of micro- and macro-empirical regularities concerning both economic and climate dynamics. Simulation experiments show a substantial lack of isomorphism between the effects of micro- and macro-level shocks, as it is typical in complex system models. In particular, different types of shocks have heterogeneous impact on output growth, unemployment rate, and the likelihood of economic crises, pointing to the importance of the different economic channel affected by the shock. Overall, we report much larger climate damages than those projected by standard IAMs under comparable scenarios, suggesting possible shifts in the growth dynamics, from a self-sustained pattern to stagnation and high volatility, and the need of urgent policy interventions

Complexity and the Economics of Climate Change: a Survey and a Look Forward

URL des Documents de travail : http://ces.univ-paris1.fr/cesdp/cesdp2016.htmlDocuments de travail du Centre d'Economie de la Sorbonne 2016.58 - ISSN : 1955-611XWe provide a survey of the micro and macro economics of climate change from a complexity science perspective and we discuss the challenges ahead for this line of research. We identify four areas of the literature where complex system models have already produced valuable insights: (i) coalition formation and climate negotiations, (ii) macroeconomic impacts of climate-related events, (iii) energy markets and (iv) diffusion of climate-friendly technologies. On each of these issues, accounting for heterogeneity, interactions and disequilibrium dynamics provides a complementary and novel perspective to the one of standard equilibrium models. Furthermore, it highlights the potential economic benefits of mitigation and adaptation policies and the risk of under-estimating systemic climate change-related risks

Complexity and the Economics of Climate Change: A Survey and a Look Forward

Climate change is one of the most daunting challenges human kind has ever faced. In the paper, we provide a survey of the micro and macro economics of climate change from a complexity science perspective and we discuss the challenges ahead for this line of research. We identify four areas of the literature where complex system models have already produced valuable insights: (i) coalition formation and climate negotiations, (ii) macroeconomic impacts of climate-related events, (iii) energy markets and (iv) diffusion of climatefriendly technologies. On each of these issues, accounting for heterogeneity, interactions and disequilibrium dynamics provides a complementary and novel perspective to the one of standard equilibrium models. Furthermore, it highlights the potential economic benefits of mitigation and adaptation policies and the risk of under-estimating systemic climate change-related risks

use of image analysis for the evaluation of rolling bottle tests results

Abstract The adhesion between bitumen and aggregates is of paramount importance for asphalt mixtures, because it is confirmed that a weak bond strength results in a premature failure of the pavement. Methods for determining the affinity or the adhesion between components are made both on loose and compacted samples. Among the first category the rolling bottle method, which is standardized in EN 12697-11 part a, is very common. It represents a simple, rapid and low cost test for an indication of the affinity between aggregate and bitumen and its influence on the susceptibility of the mixture to stripping. This paper proposes the use of 2D image analysis to evaluate the rolling bottle test results, overcoming the limits and shortcomings of the visual analysis prescribed by the reference standard. In order to demonstrate its applicability to a broad range of materials, this procedure was applied to both light and dark aggregates, mixed with a wax modified binder. The mixing temperature was varied so that the influence of the binder viscosity on the adhesion was assessed. A comparison between visual and semi-automatic estimation is presented, demonstrating that the latter brings to far better results. The accuracies were determined through confusion matrixes that permit to identify the errors made during the process of classification

Green transitions and the prevention of environmental disasters : market based vs command-and-control policies

The paper compares the effects of market-based (M-B) and command-and-control (C&C) climate policies on the direction of technical change and the prevention of environmental disasters. Drawing on a model of endogenous growth and directed technical change, we show that M-B policies (carbon taxes and subsidies toward clean sectors) suffer from path dependence and exhibit bounded window of opportunities: delays in their implementation make them ineffective both in redirecting technical change, (i.e. triggering a transition toward clean energy) and in avoiding environmental catastrophes. On the contrary, we find that C&C interventions are favored by path dependence and guarantee policy effectiveness irrespectively of the timing of their introduction. As the hypothesis of path dependence in technological change has received vast empirical support and it is a key feature of many models of growth, we argue that C&C policies should be seen as a valuable and non-equivalent alternative to M-B interventions

Salvage chemotherapy with procarbazine and fotemustine combination in the treatment of temozolomide treated recurrent glioblastoma patients

n/

High LDL levels are associated with increased lipoprotein-associated phospholipase A(2) activity on nitric oxide synthesis and reactive oxygen species formation in human endothelial cells

Objective: To evaluate in vitro the effects of serum and LDL fractions isolated from hypercholesterolemic patients on nitric oxide (NO) synthesis and reactive oxygen species (ROS) production by human umbilical vein endothelial cells (HUVECs). Design and methods: Serum and LDL isolated from subjects with high (n=18) and normal (n=21) LDL-cholesterol levels were analyzed on NO synthesis and ROS production in vitro models of HUVECs. LDL was furthers characterized in their chemical composition and activities of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), cholesteryl ester transfer protein (CETP) and paraoxonase. Results: NO bioavailability was significantly lower and ROS production higher in HUVECs incubated with serum samples from patients with high LDL-cholesterol levels in comparison to control subjects. Moreover, hypercholesterolemic patients presented higher CETP and Lp-PLA(2) activities than control subjects. LDL fractions isolated from patients and controls were not different in their chemical composition, Lp-PLA(2) activity, and their capacity to reduce NO synthesis and increase ROS production. Conclusion: Alterations of serum from hypercholesterolemic patients could be due to the increment in LDL concentration, main Lp-PLA(2) carrier, and not to LDL composition or intrinsic Lp-PLA(2) activity