Optimized Design of Hot Water Storage in Solar Thermal Cooling Facilities

Solar thermal installations can provide a significant contribution to the energy needs of cooling demand of single family buildings. Unfortunately oversizing facility elements is not uncommon. Most of the design flaws concern collector field or auxiliary elements, such as backup boilers or electric resistances inside storage devices. This leads to lower than expected facility COP and SCOP, but also higher cost. Customer dissatisfaction is the result. This paper presents a numerical model of the multiple purpose solar thermal facility installed at Universidad Carlos III de Madrid (UC3M) using the TRNSYS® tool. The solar cooling facility (http://termica.uc3m.es/solar.htm) is completely monitored for its performance characterization in the production of AC, DHW and heating. Operational data for various summer seasons have been recorded, simultaneously with 7 meteorological variables. The experimental facility includes a single effect BrLi absorption chiller working at part load under summer season. TRNSYS is a completely feasible platform for simulating solar facilities and is commonly used by researchers and planners, for its simplicity and ease manipulation. This simulation tool contains general solar cooling elements found in most experimental facilities and has been kept as simple as possible. The model developed aims at analyzing facility elements in order to resize collector field and storage volumes. Furthermore it allows studying different configurations of the facility and the control schemes. These configurations include different hot water storage capacities within the facility allowing comparing with the facility without any kind of storage excepting its own thermal inertia. The simulation has been validated with instantaneous and seasonal experimental data for different summer seasons including 2003, 2004 and 2005. Simulation results show that there is a hot storage tank capacity that optimizes the facility in terms of COP, SCOP and total cold produced. Even with no storage at all, the facility still improves its behavior from current operating conditions. Simulation and experimental results are compared and an optimum configuration of the facility is proposed.Universidad Carlos III de Madrid - ITEA Research GroupPublicad

Simulation of an absorption based solar cooling facility using a geothermal sink for heat rejection

An important issue of solar cooling facilities based on absorption cycles and sometimes not given the necessary attention is the recooling process of the absorber and condenser. This is critical in the overall behaviour of the facility because the condensation and absorption temperatures will affect the COP and cooling capacity of the chiller. Most of the time the recooling process is made by using a wet cooling tower in a closed loop through the absorber and condenser. The use of a wet cooling tower gives good results in terms of cooling capacity and COP, but presents some health risk, like legionella, and its use is restricted to the industrial sector and places where water scarcity is not present. This paper presents the modification of the already validated TRNSYS simulation of a solar cooling facility, implementing a geothermal heat sink instead of the wet cooling tower in order to dissipate the heat generated internally in the absorption chiller. Simulation results shows that a geothermal heat sink composed of 6 boreholes of 100 meters of depth should be sufficient in order to substitute the wet cooling tower, for a typical Spanish single family dwelling.Universidad Carlos III de Madrid - ITEA Research GroupPublicad

Deployment of Digital Video and Audio Over Electrical SCADA Networks

With the arrival of new hardware and software technologies, supervisory control and data acquisition human-machine interfaces (SCADA/HMI), usually text-based, can now benefit from the advantages the inclusion of multimedia information brings. However, due to the special requirements imposed by such systems, integrating audio and video data into the SCADA interfaces is not a trivial task. In this document we analyze those special characteristics and propose solutions so this integration is possible in power systems communication.Ministerio de Ciencia y Tecnología TIC2000-0367-P4-0

Myocardial trabeculation in embryos of Scyliorhinus canicula (Elasmobranchii, Chondrichthyans)

Currently, three types of ventricular myoarchitecture are recognized in vertebrates, namely compact, spongy (trabeculated) and mixed myocardium. Mixed myocardium, which has been recently proposed as the primitive condition in gnathostomes, is composed of two myocardial layers: an inner trabeculated and an outer compact one. The trabeculation process has been studied in teleosts, showing exclusively spongy myocardium, and mammals and birds, characterized by a compact myocardial ventricular wall. In zebrafish, mouse and chicken embryos, the trabeculae develop as luminal myocardial ridges protruding into the lumen. In mammals and birds, further compactation of trabeculae leads to the formation of a compact layer. The potential mechanisms that may contribute to the formation of the ridges are under discussion and include myocardial proliferation, endocardial invagination, and bending of the entire myocardial layer. However, no description of the development of the mixed myocardium is available. To shed some light on this issue, we have studied the heart development of an elasmobranch species with mixed myocardium, the lesser spotted dogfish (Scyliorhinus canicula; Chondrichthyes), by means of histological and immunohistochemical techniques for light microscopy, semithin sections, scanning electron microscopy and transmission electron microscopy. Our results suggest that in the dogfish the intertrabecular spaces develop by connections between early intramyocardial spaces and the lumen of the ventricle through invaginations of the endocardial line. Chondrichthyans are the earliest diverged lineage of gnathostomes and, consequently, they have the most primitive cardiac design. Although chicken, mouse, and recently zebrafish have been considered powerful vertebrate models to study heart development, we propose that the trabeculation process in the dogfish is representative of the early steps of the ventricular morphogenesis in vertebrates.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Study supported by grant CGL2017-85090-P and CGL2014-52356-P (Ministerio de Economía y Competitividad), FPU15/03209 (Ministerio de Educación, Cultura y Deporte), FEDER, and Universidad de Málaga

Raman spectroscopy in Group IV nanowires and nanowire axial heterostructures

The control of the SiGe NW composition is fundamental for the fabrication of high quality heterostructures. Raman spectroscopy has been used to analyse the composition of SiGe alloys. We present a study of the Raman spectrum of SiGe nanowires and SiGe/Si heterostructures. The inhomogeneity of the Ge composition deduced from the Raman spectrum is explained by the existence of a Ge-rich outer shell and by the interaction of the NW with the electromagnetic field associated with the laser beam

Dynamics of the planktonic food web in Colgada Lake (Lagunas de Ruidera Natural Park)

In Colgada Lake, one of the 15 lakes belonging to Lagunas de Ruidera Natural Park, the components of the lineal food chain (phytoplankton and metazooplankton) and the microbial loop phytoplankton, metazooplankton, ciliates, autotrophic picoplankton, and bacterioplankton) were studied from June 2003 to December 2004 with a monthly sampling frequency. This lake has monomictic and mesotrophic characteristics and a mean depth of 8 m. Sixty-two species of the phytoplankton community, 27 species of metazooplankton community, and 12 species of ciliates were identified. Phytoplankton and metazooplankton integrated biomass followed seasonal patterns with higher values in summer, up to 105 mg WW/m2 and 2 × 104 mg WW/m2, respectively. Autotrophic picoplankton did not exceed 500 mg WW/m2. Microbial loop components did not show seasonality, and its biomass concentration fluctuated between 500-2500 mg WW/m2 for ciliates and 100- 2000 mg WW/m2 for bacterioplankton. Centric Bacillariophyceae, Cryptophyceae, and Dinophyceae represented most of the phytoplanktonic biomass throughout the studied period, although an increase of cyanobacteria was also observed. Cladocerans and calanoid copepods dominated during summer stratification, rotifers and cyclopoid copepods were present during the winter mixing period. The microbial loop biomass in relation to total planktonic biomass was higher in winter and spring 2004. Interannual changes in the presence of planktonic groups were observed in the different periods of the year: i) the algal composition included larger and non-edible species (Cyanobacteria, Dinophyceae), ii) a reduction in the clearance function by cladocerans was produced, which were substituted by a cyclopoid predator that iii) can feed on rotifers and ciliates, favouring in this way bacterioplankton and autotrophic pico-nanoplankton. This interannual variation could be related to the ongoing eutrophication process in the Lake. All of this may change the way the lake looks: if spring primary production is not strongly controlled by herbivory, this could threaten the annual recruitment of submerged macrophytes that significantly contribute to improve the water quality of the lake.En la laguna Colgada, una de las 15 lagunas que componen el Parque Natural de Las lagunas de Ruidera, se han estudiado los componentes de la red trófica planctónica (fitoplancton, metazooplancton, ciliados, picoplancton autotrófico -PPA- y bacterioplancton), desde junio de 2003 a diciembre de 2004, con una frecuencia de muestreo mensual. Esta laguna posee un carácter monomíctico y mesotrófico y una profundidad media de 8 m. Se identificaron 62 especies de la comunidad fitoplanctónica, 27 especies de la comunidad de metazooplancton y 12 especies de ciliados. La biomasa integrada de fitoplancton y metazooplancton mostró un patrón estacional con valores más elevados en verano, hasta 105 mg PF/m2 y 2 × 104 mg PF/m2, respectivamente. El PPA no superó los 500 mg PF/m2. Bacterias y ciliados no presentaron estacionalidad, y su concentración fluctuó entre 500-2500 mg PF/m2 en el caso de los ciliados y 100-2000 mg PF/m2 en el bacterioplancton. Poblaciones de Bacillariophyceae de tipo centrales, Cryptophyceae y Dinophyceae constituyeron la mayor parte de la biomasa fitoplanctónica durante todo el periodo de estudio, aunque se observó un incremento de cianobacterias. Cladóceros y copépodos calanoides fueron dominantes durante la estratificación estival, rotíferos y copépodos ciclopoides estaban presentes en la mezcla invernal. La biomasa relativa del bucle microbiano frente al total de biomasa planctónica fue superior en inverno y primavera de 2004. Se han observado cambios interanuales en la presencia de los grupos planctónicos de los diferentes periodos del año: i) la composición algal incluye especies más grandes y menos comestibles (Cyanobacteria, Dinophyceae), ii) se produce una reducción de la función de aclarado de los cladóceros que son sustituidos por un depredador ciclopoide que iii) se pue de alimentar de rotíferos y ciliados, favoreciendo así a las bacterias y el pico-nanoplancton autotrófico. Esta variación interanual podría estar relacionada con el proceso de eutrofización que está sufriendo la laguna. Todo ello puede llegar a cambiar el aspecto de la laguna: si la producción primaria en primavera no está fuertemente controlada por la herbivoría, se puede impedir el reclutamiento anual de los macrófitos sumergidos que contribuyen significativamente a mejorar la calidad de la aguas de esta laguna

Supersymmetry, T-duality and heterotic α′-corrections

Higher-derivative interactions and transformation rules of the fields in the effective field theories of the massless string states are strongly constrained by space-time symmetries and dualities. Here we use an exact formulation of ten dimensional N = 1 supergravity coupled to Yang-Mills with manifest T-duality symmetry to construct the first order α′-corrections of the heterotic string effective action. The theory contains a supersymmetric and T-duality covariant generalization of the Green-Schwarz mechanism that determines the modifications to the leading order supersymmetry transformation rules of the fields. We compute the resulting field-dependent deformations of the coefficients in the supersymmetry algebra and construct the invariant action, with up to and including four-derivative terms of all the massless bosonic and fermionic fields of the heterotic string spectrum.Fil: Lescano, Eric Yair. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Nuñez, Carmen Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Rodríguez, Jesús A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentin

Estudio ornitológico de los parques y alrededores de Pamplona

Se ha estudiado la ornitofauna de 5 parques de Pamplona y 4 áreas de su periferia. Respecto al estudio cualitativo, se ha realizado una clasificación fenológica de las aves observadas, habiéndose catalogado 110 especies. En relación al estudio cuantitativo, se ha procedido a la comparación de las distintas áreas muestreadas mediante métodos estadísticos, habiéndose encontrado gran similitud entre los parques de mayor extensión incluidos en el casco de la ciudad. De igual modo se encuentra una más estrecha relación entre las áreas ribereñas del río Arga, que la existente entre otras zonas de la periferia