24 research outputs found
Viscothermal damping in thin gas or fluid layers
This paper deals with viscothermal wave propagation, including acousto-elastic interaction, For wave propagation in thin gas of fluid layers, the effects of viscosity and thermal conductivity have to be accounted for. These effects can introduce a significant dissipation of energy. A model to describe viscothermal wave propagation was developed. It includes the effect on inertia, viscosity, compressibility and thermal conductivity. It was written in terms of dimensionless parameters. These parameters govern the validity of simplifications and they can be used to put models into perspective. The viscothermal model is validated with specially designed experiments. A numerical finite element model was developed that includes the full acousto-elastic coupling. This model was also validated with experiments. The influence of barriers in a thin layers was investigated experimentally. Finally, the new techniques were applied to a number of practical problems: the damping of double wall panels and the dynamical behavior of a folded array of solar panels during launch
Effects of Climate Variability and Change on Mountain Water Resources in the Western U.S.
Spectroscopic ellipsometry studies on various zinc oxide films deposited by ion beam sputtering at room temperature
DNA Immunization Against Amyloid beta 42 has High Potential as Safe Therapy for Alzheimer’s Disease as it Diminishes Antigen-Specific Th1 and Th17 Cell Proliferation
Minority participation in a major residential and intensive outpatient program for obsessive-compulsive disorder
Spatio-temporal variability of droughts in Bolivia: 1955-2012
In this study, the spatio-temporal variability and trends of droughts across Bolivia between 1955 and 2012 were investigated using two climate drought indices: the Standardized Precipitation Index (SPI), which is based on precipitation data, and the Standardized Precipitation Evapotranspiration Index (SPEI), which is based on the difference between the precipitation and the reference evapotranspiration (ETo). We found that the average drought conditions across the country showed a temporal behaviour mainly characterized by decadal variations. The spatial pattern of drought evolution showed marked differences between the Amazonian region and the Bolivian Altiplano. Both regions showed different drought periods, a lower frequency of drought variability in the Amazon region and trends towards drier conditions in the Altiplano, mainly due to a higher atmospheric water demand as a consequence of increased ETo. We also showed that inclusion of ETo, obtained from maximum and minimum temperature records, increased the spatial heterogeneity of the drought evolution in relation to the evolution observed when only precipitation droughts were considered. The SPEI, the calculation of which includes precipitation and ETo, indicated intensification in drought severity in the last years analysed relative to the pattern found when precipitation droughts alone were considered, and also indicated an increase in the magnitude and duration of drought events. The potential for increasing drought conditions under various climate change scenarios is discussed. © 2015 Royal Meteorological Society.This work has been supported by research projects I-COOP H2O 2013CD0006: ‘Test multisectorial y actividades demostrativa sobre el potencial desarrollo de sistemas de monitorización de sequías en tiempo real en la región del oeste de Sudamérica’ financed by the Spanish National Research Council (CSIC), CGL2011-27574-CO2-02 financed by the Spanish Commission of Science and Technology and FEDER, ‘Demonstration and validation of innovative methodology for regional climate change adaptation in the Mediterranean area (LIFE MEDACC)’ financed by the LIFE programme of the European Commission, C.A.-M. received a postdoctoral fellowship # JCI-2011-10263. A.S.-L. is supported by the ‘Secretaria per a Universitats i Recerca del Departament d'Economia i Coneixement, de la Generalitat de Catalunya i del programa Cofund de les Accions Marie Curie del 7è Programa marc d'R + D de la Unió Europea’ (2011 BP-B 00078) and the postdoctoral fellowship # JCI-2012-12508.Peer Reviewe