Non-linearities in exchange rate pass-through: Evidence from smooth transition models

This paper examines the presence of non-linear mechanism in the exchange rate pass-through (ERPT) to CPI inflation for 12 euro area (EA) countries. Using smooth transition regression (STR) model, we explore the existence of non-linearities with respect to the inflation environment. We find strong evidence that pass-through respond non-linearly to inflation level for 8 out of 12 EA countries, that is, the transmission of exchange rate is higher when inflation rate surpass some threshold. Our results provide a broad support to the hypothesis suggested by Taylor (2000) that ERPT is decreasing in a lower and more stable inflation environment

Asymmetric exchange rate pass-through in the Euro area: New evidence from smooth transition models

This paper examines the presence of asymmetric behavior in exchange rate pass-through (ERPT) to CPI inflation in 12 euro area (EA) countries. Using a class of nonlinear smooth transition models, we test for asymmetry with respect to the direction and the magnitude of exchange rate changes. On the one hand, we find only 5 out of 12 EA countries showing asymmetric pass-through to exchange rate appreciations and depreciations. Results are somewhat mixed with no clear evidence about the direction of asymmetry. On the other hand, we report strong evidence that ERPT responds asymmetrically to the size of exchange rate changes as a result of presence of menu costs. The degree of ERPT is found to be higher for large exchange rate changes than for small ones in 9 out of 12 EA countries

Revisiting the Role of Inflation Environment in the Exchange Rate Pass-Through: A Panel Threshold Approach

This paper sheds new light on the role of inflation regime in explaining the extent of exchange rate pass-through (ERPT) into import prices. In order to classify his sample of 24 developing countries by regimes of inflation, Barhoumi [(2006), Differences in long run exchange rate pass-through into import prices in developing countries: An empirical investigation, Economic Modeling, 23 (6), 926-951.] chose an arbitrary threshold of 10% to split sample between high and low inflation regimes. For more accuracy, our study proposes to use a panel threshold framework where a grid search is used to select the appropriate threshold value. In a larger panel-data set including 63 countries over the period 1992-2012, we find that there are two thresholds points that are well identified by the data, allowing us to split our sample into three inflation regimes. When estimating the ERPT for each group of countries, we point out a strong regime-dependence of pass-through to inflation environment, that is, the class of countries with higher inflation rates experiences the higher degree of ERPT

Recent estimates of exchange rate pass-through to import prices in the euro area

This paper provides an update on the exchange rate pass-through (ERPT) estimates for 12 euro area (EA) countries. First, based on quarterly data over the 1990-2012 period, our study does not find a significant heterogeneity in the degree of pass-through across the monetary union members, in contrast to previous empirical studies. As we use a longer time span for the post-EA era than existing studies, this is not surprising, since the process of monetary union has entailed some convergence towards more stable macroeconomic conditions across euro area (EA) member states. Second, when assessing the stability of passthrough elasticities, we find very weak evidence of a decline around the inception of the euro in 1999. However, our results reveal that a downtrend in ERPT estimates became apparent starting from the beginning of the 1990s. This observed decline was synchronous to the shift towards reduced inflation regimes in our sample of countries. Finally, we notice that the distinction between “peripheral” and “core” EA economies in terms of pass-through has significantly decreased over the last two decades

Revue sur l'enlèvement des métaux des effluents par adsorption sur la sciure et les écorces de bois

Les résidus de transformation du bois tels les écorces et la sciure de bois ont été largement étudiés depuis quelques années pour leur propriété d'adsorption et d'enlèvement des métaux toxiques contenus dans les effluents contaminés. En ce qui concerne la sciure de bois, les recherches répertoriées ont porté principalement sur l'utilisation du sapin rouge, du manga, du tilleul, de l'épinette, du pin, du cèdre, du teck, de l'akamatsu et du buna. Pour ce qui est des écorces de bois, plusieurs espèces ont été étudiées, notamment les écorces de pin, de chêne et d'épinette. La présente revue fait le point sur les performances de ces différents adsorbants peu coûteux pour l'adsorption des principaux métaux contaminants (Cd, Cr, Cu, Hg, Ni, Pb et Zn). Les points discutés portent sur les méthodes de préparation (lavage, séchage et tamisage) et de traitement chimique de l'adsorbant (traitement acide ou basique, traitement à la formaldéhyde, phosphatation, carboxylation, sulfoéthylation, carboxyméthylation, etc.), les conditions opératoires utilisées lors de l'adsorption, les modèles thermodynamiques, cinétiques et autres applicables au couple adsorbant-adsorbat, l'effet des principaux paramètres opératoires (temps de contact, pH de traitement, température, concentration d'adsorbant, taille des particules, etc.), les principes et les mécanismes impliqués dans l'élimination des contaminants métalliques par les adsorbants présentés.Wood industry by-products such as barks and sawdusts have been widely studied in recent years for their property of metal adsorption and metal removal from contaminated effluents. Concerning the utilization of sawdusts, many researchers have studied metal adsorption on material from species such as red fir, mango, lime, pine, cedar, teak, Japanese red pine and Japanese beech. As regards wood barks, several species were studied, in particular pine, oak and spruce. The present review gives a progress report on the efficiency of these various inexpensive materials for the adsorption of different metals (Cd, Cr, Cu, Hg, Ni, Pb and Zn). The points discussed relate to the preparation methods (washing, drying, screening) and the chemical treatments of the adsorbents (acid or base treatment, formaldehyde treatment, phosphatation, carboxylation, sulfoethylation, carboxymethylation, etc.). We also consider the operating conditions used during adsorption, the thermodynamic, kinetic and other models applicable to the adsorbent-adsorbate couple, the effect of the operational parameters (time of contact, pH, temperature, adsorbent concentration, particle size, etc.), as well as the principles and mechanisms involved in metal removal by the adsorbents.The accumulation of organic or inorganic matter at the solid-liquid interface is the basis of almost all surface reactions. Adsorption is often a process described in terms of isotherms, which represent the relationship between the concentration of a solute in solution and the quantity adsorbed at the surface at constant temperature. The isotherms are often used to establish the maximum adsorption capacity of a given adsorbent for metals. Langmuir and Freundlich isotherms are the most frequently used and their models are presented in this review.Knowledge of adsorption parameters is essential for understanding the adsorption mechanisms involved. Usually, the maximum adsorption capacity for sawdusts and barks is reached after one hour. The pH of the ambient water is a very important parameter because it affects the metal adsorption capacities. For most of the metals studied, the adsorption capacity increases when the pH increases. The opposite effect is observed for metals involved in an anionic complex (Cr, Se, Pt, Au). Metal adsorption efficiency also improves with increases in substrate concentration because there are more available adsorption sites. Metal adsorption is affected by an another important factor, the particle size. In effect, a smaller size particle increases the specific surface and improves the adsorption capacity. The presence of anions in the effluent doesn't appear to have a great effect on adsorption results with sawdusts. However, some anions were reported to have an influence on the metal adsorption capacities of barks. In the case of a metal mixture, the presence of one metal may influence, compete or exclude the recovery of another metal from the solution.Sawdusts contain lignin, cellulose, tannin and protein. Wood tannin likely serves as a primary adsorption site for divalent cations. The application of chemical treatments on sawdusts could modify the lignin functional groups. Other studies regarding the participation of major components of barks (lignin, carbohydrate and protein) in the adsorption process revealed the involvement of amine and carboxyl functional groups. The proposed mechanism involves an ion-exchange process. This phenomenon suggests that cationic exchange is the active mechanism for some wood species, in agreement with the work of some researchers.Currently, only a few industries use plant biomass to eliminate metals in wastewater. To encourage industries to use this biotechnology, research has to be oriented towards the cheapest and most competitive process rather than the current and conventional process. Forest waste products are produced in large quantities in several countries. They constitute easily-available resources of low cost. Future research in this field should be focused on cheap new chemical treatments to apply to by-products to improve their adsorption capacities

Contribution of cellular automata to the understanding of corrosion phenomena

We present a stochastic CA modelling approach of corrosion based on spatially separated electrochemical half-reactions, diffusion, acido-basic neutralization in solution and passive properties of the oxide layers. Starting from different initial conditions, a single framework allows one to describe generalised corrosion, localised corrosion, reactive and passive surfaces, including occluded corrosion phenomena as well. Spontaneous spatial separation of anodic and cathodic zones is associated with bare metal and passivated metal on the surface. This separation is also related to local acidification of the solution. This spontaneous change is associated with a much faster corrosion rate. Material morphology is closely related to corrosion kinetics, which can be used for technological applications.Comment: 13 pages, 9 figure

Conception d'un outil informatique basé sur un réseau de neurones artificiels pour la classification automatique des stades du sommeil

L’objectif de notre travail est de développer un outil d’analyse automatique des stades du sommeil basé sur les réseaux de neurones artificiels (RNA). Dans ce papier nous présentons notre démarche pour la conception de cet outil. La première difficulté consiste dans le choix de la représentation des signaux physiologiques et en particulier de l’électroencéphalogramme (EEG). Une fois la représentation adoptée, l’étape suivante est la conception du réseau de neurones optimal déterminé par un processus d’apprentissage et de validation sur les données issues d’un ensemble d'enregistrements de nuits de sommeil. Le résultat obtenu avec un taux de 63% de bonne classification pour six stades, nous incite à approfondir l’étude de cette problématique aux niveaux représentation et conception pour améliorer les performances de notre outil

Etude de l'effet de la structure de la flamme sur les tubes écrans d'un générateur de vapeur à chauffe frontale

International audienceCe travail s'inscrit dans le cadre d'une approche visant à étudier le problème de la rupture soudaine des tubes écrans en 15Mo3 qui équipent les générateurs de vapeur des centrales thermiques installées dans les années 70. Cette étude est menée au travers de simulations numériques en écoulements réactifs dans un générateur de vapeur à chauffe frontale, équipant une centrale thermique d'une puissance maximale de 160 MW et fonctionnant au gaz naturel. Les simulations sont effectuées à l'aide du code de calcul industriel FLUENT, en utilisant le modèle de combustion turbulente à fonction de densité de probabilité (PDF) et le modèle de turbulence k-&#949 RNG. La discussion des résultats obtenus portera sur l'effet et l'impact de la structure de la flamme sur le développement de ce problème des tubes vaporisateurs