The Herschel view of GAS in Protoplanetary Systems (GASPS): First comparisons with a large grid of models

The Herschel GASPS key program is a survey of the gas phase of protoplanetary discs, targeting 240 objects which cover a large range of ages, spectral types, and disc properties. To interpret this large quantity of data and initiate self-consistent analyses of the gas and dust properties of protoplanetary discs, we have combined the capabilities of the radiative transfer code MCFOST with the gas thermal balance and chemistry code ProDiMo to compute a grid of ≈300  000 disc models (DENT). We present a comparison of the first Herschel/GASPS line and continuum data with the predictions from the DENT grid of models. Our objective is to test some of the main trends already identified in the DENT grid, as well as to define better empirical diagnostics to estimate the total gas mass of protoplanetary discs. Photospheric UV radiation appears to be the dominant gas-heating mechanism for Herbig stars, whereas UV excess and/or X-rays emission dominates for T Tauri stars. The DENT grid reveals the complexity in the analysis of far-IR lines and the difficulty to invert these observations into physical quantities. The combination of Herschel line observations with continuum data and/or with rotational lines in the (sub-)millimetre regime, in particular CO lines, is required for a detailed characterisation of the physical and chemical properties of circumstellar discs

Quantum fields near phantom-energy `sudden' singularities

This paper is committed to calculations near a type of future singularity driven by phantom energy. At the singularities considered, the scale factor remains finite but its derivative diverges. The general behavior of barotropic phantom energy producing this singularity is calculated under the assumption that near the singularity such fluid is the dominant contributor. We use the semiclassical formula for renormalized stress tensors of conformally invariant fields in conformally flat spacetimes and analyze the softening/enhancing of the singularity due to quantum vacuum contributions. This dynamical analysis is then compared to results from thermodynamical considerations. In both cases, the vacuum states of quantized scalar and spinor fields strengthen the accelerating expansion near the singularity whereas the vacuum states of vector fields weaken it.Comment: 6 pages RevTe

Equivalence between the real time Feynman histories and the quantum shutter approaches for the "passage time" in tunneling

We show the equivalence of the functions $G_{\rm p}(t)$ and $|\Psi(d,t)|^2$ for the ``passage time'' in tunneling. The former, obtained within the framework of the real time Feynman histories approach to the tunneling time problem, using the Gell-Mann and Hartle's decoherence functional, and the latter involving an exact analytical solution to the time-dependent Schr\"{o}dinger equation for cutoff initial waves

Web-based HMI for renewable energies microgrid through Grafana environment

[EN] Smart Grids and Microgrids require continuous monitoring and visualization of the operational state of its generation and consumption equipment. The use of Internet of Things (IoT) technology for monitoring purposes can solve limitations of traditional solutions. This paper presents a web-based Human Machine Interface (HMI) developed in the IoT software Grafana to visualize in real-time the operation of a Smart Microgrid. Photovoltaic generation is combined with hydrogen production and consumption in the microgrid. The main magnitudes of the components are measured and graphically displayed through a user-friendly web interface. Experimental results are reported to prove the suitability of the developed HMI

PV panel monitoring system for cell temperature analysis and comparison by embedded models

[EN] In recent decades, the use of renewable energy sources and the development of related technologies have been boosted due to the energy and environmental paradigm, with photovoltaic (PV) panels being one of the most implemented and optimised to date. The behaviour of panel operation is dependent on multiple parameters such as irradiance, wind speed or operating temperature. This paper presents a monitoring system based on IoT software focused on the study of the cell temperature (CT) of PV panels, highlighting the importance of this variable in the current generation and the equipment overall performance. For this purpose, a dashboard is implemented in Grafana to visualise the evolution of the CT and the associated variables. The implemented dashboard includes embedded models for the simulation of CT, in order to compare real and simulation data. This comparison determines the most suitable model to the real dynamics and could facilitate the development of intelligent control strategies for the pane

Enfriamiento hidrónico de la masa térmica del concreto

This article features an analysis of the active radiant hydronic system as a thermic mass cooling system of concrete and the time which this cooling process is being made on the sub-humid mild climate temperature (Mexico City, Mexico) and the warm humid climate temperature (San Pedro Sula, Honduras). The research develop two concrete prototypes, a hydronic system and the another one as a reference to compare the system functionality. On Mexico City’s weather, the concrete thermic mass diminishes 6.73 °C in comparison with the environment temperature. At San Pedro Sula, the concrete thermic mass diminishes 3.32°C in comparison with the environment temperature as well. Reason why this system’s functions works better on sub-humid mild climate temperature because of the high dew temperature is lower than the warm humid climate temperature, so that the water temperature circulation is lower, leveling up the heat absorption from the concrete thermic mass.El presente artículo realiza un análisis del sistema hidrónico radiante activo como sistema de enfriamiento de la masa térmica del concreto y en cuanto tiempo se realiza dicho enfriamiento en clima templado subhúmedo (ciudad de México, México) y en clima cálido húmedo (ciudad de San Pedro Sula, Honduras). En la investigación se realiza dos prototipos de concreto, uno con el sistema hidrónico y el otro como referencia, para comparar el funcionamiento del sistema. En el clima de la Ciudad de México, la masa térmica del concreto disminuyó 6.73°C con respecto a la temperatura del ambiente. En la ciudad de San Pedro Sula, la masa térmica del concreto disminuyó 3.32°C con respecto a la temperatura del ambiente. Por lo que el sistema posee un mejor funcionamiento en clima templado subhúmedo debido a que la temperatura de rocío es más baja que en clima cálido-húmedo, por lo que la temperatura del agua para la circulación del sistema es menor, incrementando la absorción del calor de la masa térmica del concreto

Quantum fields and "Big Rip" expansion singularities

The effects of quantized conformally invariant massless fields on the evolution of cosmological models containing a ``Big Rip'' future expansion singularity are examined. Quantized scalar, spinor, and vector fields are found to strengthen the accelerating expansion of such models as they approach the expansion singularity.Comment: 7 pages; REVTeX

Poplar roundwood yield : according to diameter classes

El conocimiento de los rendimientos de la madera de álamo es importante para establecer alternativas de uso, lograr el máximo aprovechamiento y, a su vez, calcular los costos foresto-industriales. El objetivo de este trabajo fue determinar los rendimientos de aserrío de una muestra de Populus x deltoides cv. Harvard, según clases diamétricas. Los rendimientos de aserrío variaron de acuerdo con el diámetro, desde 65 % 45 a 65 %, para diámetros de rollizos de 10 a 40 cm.The knowledge of poplar wood yields is very important to constitute the diferent uses, to maximize his utility, and to calcúlate the forestal industrial costs. The objective of this paper is the determination of sawmill yields of a Populus x deltoides cv. Harvard sample according to diameter classes. Sawmill yields situates between 45 to reciprocate to diameters between 10 to 40 cm.Fil: Calderón, Alberto D.. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción AgropecuariaFil: Mastrantonio, Leandro. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Producción Agropecuari