Nonlinear Monetary Policy Rules: Some New Evidence for the U.S.

This paper derives optimal monetary policy rules in setups where certainty equivalence does not hold because either central bank preferences are not quadratic, and/or the aggregate supply relation is nonlinear. Analytical results show that these features lead to sign and size asymmetries, and nonlinearities in the policy rule. Reduced-form estimates indicate that US monetary policy can be characterized by a nonlinear policy rule after 1983, but not before 1979. This finding is consistent with the view that the Fed's inflation preferences during the Volcker-Greenspan regime differ considerably from the ones during the Burns-Miller regime.Dans cet article, nous dérivons les règles de politique monétaire optimales dans des cadres où \"l'équivalence certaine\" n'est pas satisfaite. On trouve des cas de ce type lorsque, par exemple, les préférences de la banque centrale ne sont pas quadratiques ou lorsque la relation d'offre agrégée n'est pas linéaire. Les résultats théoriques semblent montrer qu'ils peuvent conduire à des asymétries de signe et de niveau et à des nonlinéarités dans la règle de politique. À partir d'estimations de la forme réduite sur données américaines, nous trouvons que la politique monétaire des États-Unis peut être caractérisée par une règle décisionnelle non linéaire après 1983, mais que ce n'est pas le cas avant 1979. Ces résultats reflètent bien la nette différence d'attitude de la Réserve Fédérale face à l'inflation durant les périodes Volcker-Greenspan et Burns-Miller

Mapping of mechanical properties of cement paste microstructures

The presented study is related to the EU 7 th Framework Programme CODICE (COmputationally Driven design of Innovative CEment-based materials). The main aim of the project is the development of a multi-scale model for the computer based simulation of mechanical and durability performance of cementitious materials. This paper reports results of micro/nano scale characterisation and mechanical property mapping of cementitious skeletons formed by the cement hydration at different ages. Using the statistical nanoindentation and micro-mechanical property mapping technique, intrinsic properties of different hydrate phases, and also the possible interaction (or overlapping) of different phases (e.g. calcium-silcate-hydrates) has been studied. Results of the mapping and statistical indentation testing appear to suggest the possible existence of more hydrate phases than the commonly reported LD and HD C-S-H and CH phase

Mineralogical evolution of Portland cement blended with silica nanoparticles and its effect on mechanical strength

Mineralogical analysis on pastes of Spanish Portland cement Type I, blended with nanosilica was carried out by conventional and high-resolution thermogravimetric analysis (TG-HRTG) and X-ray diffraction (XRD) in order to determine the quantity of the different mineralogical phases obtained during the hydration process. Simultaneously, mortars with the same materials and replacement ratio were made in order to assess their compressive strength for up to 28 days of curing time. In this paper, the rate and quantity of each one of the main constituent phases of the cement during its hydration process (CSH, portlandite, stratlingite, etc.) were determined. A correlation between the quantity of CSH and the development of compressive strength was established. Additionally, the pozzolanic activity of nanosilica was evaluated by quantifying the fixation of calcium hydroxide and its impact on the development of the compressive strength. © 2012 Elsevier Ltd. All rights reserved.The authors express their thanks to Cementos Argos S.A. and to COLCIENCIAS (Project 20201007768) of Colombia for their financial support in the execution of this research.Tobón, JI.; Paya Bernabeu, JJ.; Borrachero Rosado, MV.; Restrepo Baena, OJ. (2012). Mineralogical evolution of Portland cement blended with silica nanoparticles and its effect on mechanical strength. Construction and Building Materials. 36:736-742. https://doi.org/10.1016/j.conbuildmat.2012.06.043S7367423

Nonlinear Monetary Policy Rules: Some New Evidence for the U.S.

This paper derives optimal monetary policy rules in setups where certainty equivalence does not hold because either central bank preferences are not quadratic, and/or the aggregate supply relation is nonlinear. Analytical results show that these features lead to sign and size asymmetries, and nonlinearities in the policy rule. Reduced-form estimates indicate that US monetary policy can be characterized by a nonlinear policy rule after 1983, but not before 1979. This finding is consistent with the view that the Fed's inflation preferences during the Volcker-Greenspan regime differ considerably from the ones during the Burns-Miller regime.Nonlinear Taylor rules, inflation targets, asymmetric preferences, nonlinear Phillips curve, monetary policy

Nonlinear Monetary Policy Rules: Some New Evidence for the U.S.

This paper derives optimal monetary policy rules in setups where certainty equivalence does not hold because either central bank preferences are not quadratic, and/or the aggregate supply relation is nonlinear. Analytical results show that these features lead to sign and size asymmetries, and nonlinearities in the policy rule. Reduced-form estimates indicate that US monetary policy can be characterized by a nonlinear policy rule after 1983, but not before 1979. This finding is consistent with the view that the Fed's inflation preferences during the Volcker-Greenspan regime differ considerably from the ones during the Burns-Miller regime.nonlinear Taylor rules, inflation targets, asymmetric eferences, non- linear Philli curve, monetary licy

Effect of Chemical Environment on the Dynamics of Water Confined in Calcium Silicate Minerals: Natural and Synthetic Tobermorite

Confined water in the slit mesopores of the mineral tobermorite provides an excellent model system for analyzing the dynamic properties of water confined in cement-like materials. In this work, we use broadband dielectric spectroscopy (BDS) to analyze the dynamic of water entrapped in this crystalline material. Two samples, one natural and one synthetic, were analyzed, and despite their similar structure, the motion of confined water in their zeolitic cavity displays considerably different behavior. The water dynamics splits into two different behaviors depending on the chemical nature of the otherwise identical structural environment: water molecules located in areas where the primary building units are SiO4 relax slowly compared to water molecules located in cavities built with both AlO4 and SiO4. Compared to water confined in regular porous systems, water restricted in tobermorite is slower, indicating that the mesopore structure induces high disorder in the water structure. A comparison with water confined in the C-S-H gel is also discussed in this work. The strong dynamical changes in water due to the presence of aluminum might have important implications in the chemical transport of ions within hydrated calcium silicates, a process that governs the leaching and chemical degradation of cement.Basque government through the Nanoiker Project under the ETORTEK Program (IE14-393), Spanish Ministry of Education (MAT2012-31088), Spanish Ministerio de Industria y Competitividad (Juan de la Cierva