Maximum power, ecological function and efficiency of an irreversible Carnot cycle. A cost and effectiveness optimization

In this work we include, for the Carnot cycle, irreversibilities of linear finite rate of heat transferences between the heat engine and its reservoirs, heat leak between the reservoirs and internal dissipations of the working fluid. A first optimization of the power output, the efficiency and ecological function of an irreversible Carnot cycle, with respect to: internal temperature ratio, time ratio for the heat exchange and the allocation ratio of the heat exchangers; is performed. For the second and third optimizations, the optimum values for the time ratio and internal temperature ratio are substituted into the equation of power and, then, the optimizations with respect to the cost and effectiveness ratio of the heat exchangers are performed. Finally, a criterion of partial optimization for the class of irreversible Carnot engines is herein presented.Comment: 17 pages, 4 figures. Submitted to Energy Convers. Manag

F-algebra–Rinehart pairs and super F-algebroids

We define F-algebra--Rinehart pairs and super F-algebroids and study theconnection between them.<br

Optimizing Scan Homogeneity for Building Full-3D Lidars based on Rotating a Multi-Beam Velodyne Rangefinder

Multi-beam lidar (MBL) scanners are compact, light, and accessible 3D sensors with high data rates, but they offer limited vertical resolution and field of view (FOV). Some recent robotics research has profited from the addition of a degree-of-freedom (DOF) to an MBL to build rotating multi-beam lidars (RMBL) that can achieve high-resolution scans with full spherical FOV. In a previous work, we offered a methodology to analyze the complex 3D scan measurement distributions produced by RMBLs with a rolling DOF and no pitching. In this paper, we investigate the effect of introducing constant pitch angles in the construction of the RMBLs with the purpose of finding a kinematic configuration that optimizes scan homogeneity with a spherical FOV. To this end, we propose a scalar index of 3D sensor homogeneity that is based on the spherical formulation of Ripley's K function. The optimization is performed for the widely used Puck (VLP-16) and HDL-32 sensors by Velodyne.This work was partially funded by the Spanish project {DPI2015-65186-R}. The publication has received support from Universidad de Málaga, Campus de Excelencia Andalucía Tech

Crecimiento y caracterización de películas delgadas de tio2 y ti1- xfexo2

Titanium dioxide (TiO2) and Fe-doped titanium dioxide (Ti1-xFexO2) thin films were grown on silicon substrates using the magnetron sputtering Rf (13.56 MHz) technique. The relevant growth parameters for the samples (pressure, power, gas mixture ratio, distance between target-substrate, among others) were found. The plasma deposition environment for the ternary films was characterized by optical emission spectroscopy in order to verify and identify the present species which were iron and titanium. The TiO2 films, deposited on silicon substrates [100], showed an amorphous phase while the ternary films showed low crystallinity. After annealing at 800 °C crystalline phases appeared, rutile in binary films and mixed in ternary films.Fil: Galvis, J.. Universidad de Antioquia; ColombiaFil: Ramirez Jimenez, Helena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Montes, J.. Universidad de Antioquia; ColombiaFil: Sanchez, L.. Universidad de Antioquia; ColombiaFil: Beltran, J.. Universidad de Antioquia; ColombiaFil: Barrero, C.. Universidad de Antioquia; ColombiaFil: Morales, A.. Universidad de Antioquia; ColombiaFil: Gomez, J.. Universidad del Quindío; ColombiaFil: Tirado Mejia, L.. Universidad del Quindío; ColombiaFil: Osorio, J.. Universidad de Antioquia; Colombi

Photometry and Multipolar Magnetic Field Modeling of Polars: BY Camelopardalis and FL Ceti

We present new broad band optical photometry of two magnetic cataclysmic variable stars, the asynchronous polar BY Camelopardalis and the short period polar FL Ceti. Observations were obtained at the 2.1-m Otto Struve Telescope of McDonald Observatory with 3s and 1s integration times respectively. In an attempt to understand the observed complex changes in accretion flow geometry observed in BY Cam, we performed full 3D MHD simulations assuming a variety of white dwarf magnetic field structures. We investigate fields with increasing complexity including both aligned and non-aligned dipole plus quadrupole field components. We compare model predictions with photometry at various phases of the beat cycle and find that synthetic light curves derived from a multipolar field structure are broadly consistent with optical photometry. FL Ceti is observed to have two very small accretion regions at the foot-points of the white dwarf’s magnetic field. Both accretion regions are visible at the same time in the high state and are about 100 degrees apart. MHD modeling using a dipole plus quadrupole field structure yields quite similar accretion regions as those observed in FL Ceti. We conclude that accretion flows calculated from MHD modeling of multi-polar magnetic fields produce synthetic light curves consistent with photometry of these magnetic cataclysmic variables

Ecology of the Mayan Cichlid, Cichlasoma urophthalmus Günther, in the Alvarado Lagoonal System, Veracruz, Mexico

The Mayan cichlid, Cichlasoma urophthalmus, has a wide distribution in southeastern Mexico where it inhabits rivers and coastal lagoons. In the Alvarado lagoonal system, Veracruz, it is distributed towards the north in Camaronera Lagoon. The Mayan cichlid shows an affinity for oligohaline to mesohaline sites with submerged vegetation, well-oxygenated, deep, and transparent water. The major abundance and biomass of this species was obtained during December to February. The diet of Mayan cichlids consists principally of plant detrital material and algae. Length-frequency distribution shows 2 size classes during both the dry and rainy seasons, corresponding to reproductive fish and young of the year; during the nortes season there is only one modal size class of fish between 60–100 mm SL. Individuals with developed gonads are found throughout the year, although most reproductive adults are found between April and December. The highest Gonadosomatic Index (GSI) values coincided with the peak in reproductive activity between May and July. The fecundity ranged from 1,556–3,348 eggs/female, and there was no relationship between female size and fecundity

Evidence Against the Sciama Model of Radiative Decay of Massive Neutrinos

We report on spectral observations of the night sky in the band around 900 angstroms where the emission line in the Sciama model of radiatively decaying massive neutrinos would be present. The data were obtained with a high resolution, high sensitivity spectrometer flown on the Spanish MINISAT satellite. The observed emission is far less intense than that expected in the Sciama model.Comment: 9 pages, accepted to Ap

Recovering and Exploiting Aragonite and Calcite Single Crystals with Biologically Controlled Shapes from Mussel Shells

Control over the shape and morphology of single crystals is a theme of great interest in fundamental science and for technological application. Many synthetic strategies to achieve this goal are inspired by biomineralization processes. Indeed, organisms are able to produce crystals with high fidelity in shape and morphology utilizing macromolecules that act as modifiers. An alternative strategy can be the recovery of crystals from biomineralization products, in this case, seashells. In particular, waste mussel shells from aquaculture are considered. They are mainly built up of single crystals of calcite fibers and aragonite tablets forming an outer and an inner layer, respectively. A simple mechanochemical treatment has been developed to separate and recover these two typologies of single crystals. The characterization of these single crystals showed peculiar properties with respect to the calcium carbonate from quarry or synthesis. We exploited these biomaterials in the water remediation field using them as substrate adsorbing dyes. We found that these substrates show a high capability of adsorption for anionic dye, such as Eosin Y, but a low capability of adsorption for cationic dyes, such as Blue Methylene. The adsorption was reversible at pH 5.6. This application represents just an example of the potential use of these biogenic single crystals. We also envision potential applications as reinforcing fillers and optical devices

Calidad y sostenibilidad : una propuesta metodológica interdisciplinar para la innovación competitiva de los municipios turísticos maduros

En el contexto de las primeras manifestaciones de una fase recesiva relacionada con la falta de competitividad de los destinos de sol y playa convencionales en países desarrollados en comparación con los análogos de países emergentes, se esgrimen como alternativa la evolución hacia un modelo de excelencia, identificado con calidad ambiental y calidad en el servicio. En el artículo se presenta una propuesta metodológica que tiene como objetivo fundamental reorientar la actitud de los agentes sociales de los municipios correspondientes a estos destinos hacia aquella que facilite la asunción por éstos de los criterios de calidad y sostenibilidad en sus prácticas económicas y territoriales. Esta metodología tiene un carácter interdisciplinar desde dos dimensiones. Una definida por la combinación de metodologías procedentes de dos áreas temáticas: los estudios turísticos y los estudios sobre procesos de innovación en el marco del desarrollo local. Otra, aportada por la composición del equipo, integrado por geógrafos, antropólogos y economistas.Environmental quality (sustainability) and service quality are being argued as a way to do more competitive the mature sun and beach destination, that are living the competition of young destinations. This paper presents a methodologic proposal whose main aim is helping to the local stakeholders in these destination to modify their behaviour in order to take on their economic and environmental skills these issues of sustainability and quality. This methodology is interdisciplinary in two ways: On the one hand, it arranges the methodologies belonging to tourist studies with that of the local development studies. On the other hand, it arranges the methodologies belonging to the study workteam: geographers, anthropologists and economists