Optimal interpolation of satellite and ground data for irradiance nowcasting at city scales

We use a Bayesian method, optimal interpolation, to improve satellite derived irradiance estimates at city-scales using ground sensor data. Optimal interpolation requires error covariances in the satellite estimates and ground data, which define how information from the sensor locations is distributed across a large area. We describe three methods to choose such covariances, including a covariance parameterization that depends on the relative cloudiness between locations. Results are computed with ground data from 22 sensors over a 75×80 km area centered on Tucson, AZ, using two satellite derived irradiance models. The improvements in standard error metrics for both satellite models indicate that our approach is applicable to additional satellite derived irradiance models. We also show that optimal interpolation can nearly eliminate mean bias error and improve the root mean squared error by 50%

Thermal Excitation of Broadband and Long-range Surface Waves on SiO 2 Submicron Films

We detect thermally excited surfaces waves on a submicron SiO 2 layer, including Zenneck and guided modes in addition to Surface Phonon Polaritons. The measurements show the existence of these hybrid thermal-electromagnetic waves from near-(2.7 $\mu$m) to far-(11.2 $\mu$m) infrared. Their propagation distances reach values on the order of the millimeter, several orders of magnitude larger than on semi-infinite systems. These two features, spectral broadness and long range propagation, make these waves good candidates for near-field applications both in optics and thermics due to their dual nature.Comment: Applied Physics Letters, American Institute of Physics, 201

A large sample analysis of European rivers on seasonal river flow correlation and its physical drivers

The geophysical and hydrological processes governing river flow formation exhibit persistence at several timescales, which may manifest itself with the presence of positive seasonal correlation of streamflow at several different time lags. We investigate here how persistence propagates along subsequent seasons and affects low and high flows. We define the high-flow season (HFS) and the low-flow season (LFS) as the 3-month and the 1-month periods which usually exhibit the higher and lower river flows, respectively. A dataset of 224 rivers from six European countries spanning more than 50 years of daily flow data is exploited. We compute the lagged seasonal correlation between selected river flow signatures, in HFS and LFS, and the average river flow in the antecedent months. Signatures are peak and average river flow for HFS and LFS, respectively. We investigate the links between seasonal streamflow correlation and various physiographic catchment characteristics and hydro-climatic properties. We find persistence to be more intense for LFS signatures than HFS. To exploit the seasonal correlation in the frequency estimation of high and low flows, we fit a bi-variate meta-Gaussian probability distribution to the selected flow signatures and average flow in the antecedent months in order to condition the distribution of high and low flows in the HFS and LFS, respectively, upon river flow observations in the previous months. The benefit of the suggested methodology is demonstrated by updating the frequency distribution of high and low flows one season in advance in a real-world case. Our findings suggest that there is a traceable physical basis for river memory which, in turn, can be statistically assimilated into high- and low-flow frequency estimation to reduce uncertainty and improve predictions for technical purposes

Grafitos sobre Terra Sigillata Hispánica hallados en un vertedero del siglo I en la casa de Hippolytus (Complutum)

Presentamos en este estudio un conjunto de materiales inéditos del yacimiento romano de "hippolytus". Estos grafitos, presentes en la mayoría de los establecimientos romanos, no han recibido, en algunas ocasiones, la debida atención por parte de los investigadores. Su análisis pormenorizado, junto a la evidente ventaja de provenir de un contexto arqueológico cerrado y bien definido, nos acerca al conocimiento de las relaciones sociales, parentesco y origen de los moradores de este nuevo enclave altoimperial complutense

On the Taylor-Quinney coefficient in dynamically phase transforming materials. Application to 304 stainless steel

We present a thermodynamic scheme to capture the variability of the Taylor-Quinney coefficient in austenitic steels showing strain induced martensitic transformation at high strain rates. For that task, the constitutive description due to Zaera et al. (2012) has been extended to account for the heat sources involved in the temperature increase of the material. These are the latent heat released due to the exothermic character of the transformation and the heat dissipated due to austenite and martensite straining. Through a differential treatment of these dissipative terms, the Taylor-Quinney coefficient develops a direct connection with the martensitic transformation becoming stress, strain and strain rate dependent. The improved constitutive description sheds light on experimental results available in the literature reporting unusual (> 1) values for the Taylor-Quinney coefficient.The researchers of the University Carlos III of Madrid are indebted to the Comunidad Autónoma de Madrid (Project CCG10-UC3M/DPI-5596)) and to the Ministerio de Ciencia e Innovación de España (Project DPI/2011-24068) for the financial support received which allowed conducting part of this work. D. Rittel acknowledges the support of Carlos III University with a Cátedra de Excelencia funded by Banco Santander during academic year 2011–2012.Publicad

Análisis de intensidades energéticas y emisiones de CO2 a partir de la matriz de contabilidad social de Andalucía del año 2000

RESUMEN: En este artículo se estiman las intensidades energéticas y emisiones de CO2 para la economía andaluza en el año 2000. Las intensidades energéticas de las ramas productivas se calculan en varios escenarios empleando un modelo SAM especificado con la matriz de contabilidad social elaborada por los autores. Las emisiones se estiman con el modelo input-output, distinguiendo la polución intermedia de la originada por la demanda final. Los resultados muestran la existencia de importantes variaciones en intensidades entre ramas y también las sustanciales variaciones que acaecen al endogeneizar el consumo y la inversión. La estimación de las emisiones en el año base resulta bastante satisfactoria y las simulaciones realizadas muestran el sustancial impacto que tienen los incrementos de la demanda final interior.Emisiones de CO2, matriz de contabilidad social, multiplicadores energéticos, Agricultural and Food Policy, D57, D58, Q51,

Finite element analysis of AISI 304 steel sheets subjected to dynamic tension: The effects of martensitic transformation and plastic strain development on flow localization

The paper presents a finite element study of the dynamic necking formation and energy absorption in AISI 304 steel sheets. The analysis emphasizes the effects of strain induced martensitic transformation (SIMT) and plastic strain development on flow localization and sample ductility. The material behavior is described by a constitutive model proposed by the authors which includes the SIMT at high strain rates. The process of martensitic transformation is alternatively switched on and off in the simulations in order to highlight its effect on the necking inception. Two different initial conditions have been applied: specimen at rest which is representative of a regular dynamic tensile test, and specimen with a prescribed initial velocity field in the gauge which minimizes longitudinal plastic wave propagation in the tensile specimen. Plastic waves are found to be responsible for a shift in the neck location, may also mask the actual constitutive performance of the material, hiding the expected increase in ductility and energy absorption linked to the improved strain hardening effect of martensitic transformation. On the contrary, initializing the velocity field leads to a symmetric necking pattern of the kind described in theoretical works, which reveals the actual material behavior. Finally the analysis shows that in absence of plastic waves, and under high loading rates, the SIMT may not further increase the material ductility.D. Rittel acknowledges the support of Carlos III University with a Cátedra de Excelencia funded by Banco Santander during academic year 2011-2012. The researchers of the University Carlos III of Madrid are indebted to the Comunidad Autónoma de Madrid (Project CCG10 UC3M/DPI 5596) and to the Ministerio de Ciencia e Innovación de España (Project DPI/2008 06408) for the financial support received which allowed conducting part of this work

EDROOM: a free tool for the UML2 component based design and automatic code generation of tiny embedded real time system

International audienceThe use of tiny real time kernels to develop embedded systems is broadly extended. They offer basic services with small overhead footprints in the final product. Usually, these kind of kernels are compliant with the POSIX 1003.13 specification. The use of graphical modelling and automatic code generation tools for developing these kind of small software embedded system if often not considered for several reasons: they are expensive, the learning curve to obtain benefits is often large and finally the generated code usually does not fit well with the platform or exceed the desired size. In this paper we present the adaptation of a free tool, known as EDROOM, to develop this kind of real time software system. EDROOM is inspired on the ROOM modelling language and provides graphical modelling and automatic Embedded C++ code generation. EDROOM is compliant with the new UML2 graphical notation for component based system design and hierarchical behaviour. The new version of EDROOM is a cross development multiplatform generation tool and includes facilities for static control of all resources in order to completely avoid the use of dynamic memory. Our tool has been used in the software development of a small satellite (NANOSAT-01) which is fully functional nowadays. The tool is free distributed in conjunction with a group of code test bench that can be used to validate any port to another architecture