A refined analysis of the low-mass eclipsing binary system T-Cyg1-12664

The observational mass-radius relation of main sequence stars with masses between ~0.3 and 1.0 Msun reveals deviations between the stellar radii predicted by models and the observed radii of stars in detached binaries. We generate an accurate physical model of the low-mass eclipsing binary T-Cyg1-12664 in the Kepler mission field to measure the physical parameters of its components and to compare them with the prediction of theoretical stellar evolution models. We analyze the Kepler mission light curve of T-Cyg1-12664 to accurately measure the times and phases of the primary and secondary eclipse. In addition, we measure the rotational period of the primary component by analyzing the out-of-eclipse oscillations that are due to spots. We accurately constrain the effective temperature of the system using ground-based absolute photometry in B, V, Rc, and Ic. We also obtain and analyze V, Rc, Ic differential light curves to measure the eccentricity and the orbital inclination of the system, and a precise Teff ratio. From the joint analysis of new radial velocities and those in the literature we measure the individual masses of the stars. Finally, we use the PHOEBE code to generate a physical model of the system. T-Cyg1-12664 is a low eccentricity system, located d=360+/-22 pc away from us, with an orbital period of P=4.1287955(4) days, and an orbital inclination i=86.969+/-0.056 degrees. It is composed of two very different stars with an active G6 primary with Teff1=5560+/-160 K, M1=0.680+/-0.045 Msun, R1=0.799+/-0.017 Rsun, and a M3V secondary star with Teff2=3460+/-210 K, M2=0.376+/-0.017 Msun, and R2=0.3475+/-0.0081 Rsun. The primary star is an oversized and spotted active star, hotter than the stars in its mass range. The secondary is a cool star near the mass boundary for fully convective stars (M~0.35 Msun), whose parameters appear to be in agreement with low-mass stellar model.Comment: 18 pages, 15 figures, 15 table

Structural Characterization of Linear Three-Dimensional Random Chains: Energetic Behaviour and Anisotropy

In this work, we will make an energetic and structural characterization of three-dimensional linear chains generated from a simple self-avoiding random walk process in a finite time, without boundary conditions, without the need to explore all possible configurations. From the analysis of the energy balance between the terms of interaction and bending (or correlation), it is shown that the chains, during their growth process, initially tend to form clusters, leading to an increase in their interaction and bending energies. Larger chains tend to “escape” from the cluster when they reach a number of “steps” N>∼1040 , resulting in a decrease in their interaction energy, however, maintaining the same behavior as flexion energy or correlation. This behavior of the bending term in the energy allows distinguishing chains with the same interaction energy that present different structures. As a complement to the energy analysis, we carry out a study based on the moments of inertia of the chains and their radius of gyration. The results show that the formation of clusters separated by “tails” leads to a final “prolate” structure for this type of chain, the same structure evident in real polymeric linear chains in a good solvent

Reasonable Non-conventional Generator of Random Linear Chains Based on a Simple Self-avoiding Walking Process: A Statistical and Fractal Analysis

Models based on self-excluded walks have been widely used to generate random linear chains. In this work, we present an algorithm capable of generating linear strings in two and three dimensions, in a simple and efficient way. The discrete growth process of the chains takes place in a finite time, in a network without pre-established boundary conditions and without the need to explore the entire configurational space. The computational processing time and the length of the strings depending on the number of trials N′ . This number is always less than the real number of steps in the chain, N. From the statistical analysis of the characteristic distances, the radius of gyration ( Rg ), and the end-to-end distance ( Ree ), we make a morphological description of the chains and we study the dependence of this quantities on the number of steps, N. The universal critical exponent obtained are in very good agreement with previous values reported in literature. We also study fractal characteristics of the chains using two different methods, Box-Counting Dimension or Capacity Dimension and Correlation Dimension. The studies revealed essential differences between chains of different dimensions, for the two methods used, showing that three-dimensional chains are more correlated than two-dimensional chains

Comprehensive transient-state study for CARMENES-NIR high thermal stability

CARMENES has been proposed as a next-generation instrument for the 3.5m Calar Alto Telescope. Its objective is finding habitable exoplanets around M dwarfs through radial velocity measurements (m/s level) in the near-infrared. Consequently, the NIR spectrograph is highly constraint regarding thermal/mechanical requirements. As a first approach, the thermal stability has been limited to \pm 0.01K (within year period) over a working temperature of 243K. This can be achieved by means of several temperature-controlled rooms. The options considered to minimise the complexity of the thermal design are here presented, as well as the transient-state thermal analyses realised to make the best choice

Path Planning Approach for a Quadrotor Unmanned Aerial Vehicle

A path planning method for an unmanned aerial system type quadrotor is proposed in this work. It is based on Dubins curves. Therefore, different points (initial and ending) are set for generation of several paths. Additionally, to validate the proposed model a computational resource is applied. Also, some flight dynamics limits and orientation angles computations are considered to be able to determine a simplified Dubins model. Dubins paths are commonly divided into low, medium and high altitude gains. It will depend on the altitude established for the start and end points and other configurations

OpenFOAM Numerical Simulations with Different Lid Driven Cavity Shapes

The finite volume method have been developed to solve the Navier-Stokes equations with primitive variables and non dimensional form. This work examine the classical benchmark problem of the lid-driven cavity at a different Reynolds range (Re = 10,100,400, 1000, 2000, 3200) and several cavity geometries. The cavity configurations include square cavity, skewed cavity, trapezoidal cavity and arcshaped cavity. The flow is assumed laminar and solved in a uniform mesh. A CFD tool with its solvers (icoFoam) will be used for this study

Fire response of the endangered Pinus culminicola stands after 18 years in Cerro El Potosí, northeast Mexico

Abstract Aim of the study: To analyze the impact of the 1998 wildfire on dwarf pine (Pinus culminicola) population stands 18 years after the fire. Area of study: Cerro el Potosí, Nuevo León (México). Material and methods: We measured regeneration, biovolume of individuals, diversity and species composition in unburned and burned plots randomly selected in the area. Main results: Recovery was very slow, with limited dense natural regeneration and very slow growth. Significant differences between control and burned plots were found with respect to regeneration, species composition, evenness and soil nutrients, suggesting that fire could promote natural regeneration and biodiversity in these communities. Research highlights: Management efforts are necessary to maintain a natural fire regime and ensure grazing exclusion in order to favor the conservation of the community dominated by this rare species P. culminicola. Additional keywords: fire ecology; DCA; Permanova; richness. Abbreviations used: CIC (Cationic Interchange Complex); DCA (Detrended Correspondence Analysis); EC (Exchangeable Cation); OM (Organic Matter). Authors´ contributions: Conceived, designed and performed the experiments: JRA, EE and HGR. Analyzed the data: JRA, JAV, JRE and YM. Contributed reagents/materials/analysis tools: JAV, JRE, YM, IC and JU. Wrote the paper: JRA, JAE and EE. All authors read and approved the final manuscript. Citation: Arévalo, J. R.; Estrada, E.; Encina, J. A.; Villarreal, J. A.; Escobedo, J. R.; Morales, Y.; Cantú, I.; González-Rodríguez, H.; Uvalle, J. (2017). Fire response of the endangered Pinus culminicola stands after 18 years in Cerro El Potosí, northeast Mexico. Forest Systems, Volume 26, Issue 3, e015. https://doi.org/10.5424/fs/2017263-11566 Received: 20 Apr 2017. Accepted: 21 Nov 2017. Copyright © 2017 INIA. This is an open access article distributed under the terms of the Creative Commons Attribution (CC-by) Spain 3.0 License. Funding: Program of cooperation Universidad de La Laguna-Universidad Autónoma de Nuevo León, included in the official frame agreement of these institutions; Facultad de Ciencias Forestales of the Universidad Autónoma de Nuevo León; University of La Laguna (Research Program) covered the travel expenses of JRA. Competing interests: The authors have declared that no competing interests exist. Correspondence should be addressed to José R. Arévalo: [email protected]

Novel Method for Wind Turbines Blades Damage Classification using Image Processing

Wind turbine generators are spreading around the world due to its advantages over fossil fuels. Structural monitoring of them is important to increase operation and reduce maintenance times. Visual inspection is highly influenced by the human factor due to the working conditions. Image processing supported by vision systems offers high advantages reducing times, being the software and processing algorithms, which generates added value. In this paper, a novel method for wind turbines blades damages analysis is presented using image processing and a classifier based on dimensional features. The image acquisition is performed using a reflex camera with a telephoto and geo-location enabled. The faults analyzed include cracks, edge erosion, and electric discharge

Novel Method for Wind Turbines Blades Damage Classification using Image Processing

75-79Wind turbine generators are spreading around the world due to its advantages over fossil fuels. Structural monitoring of them is important to increase operation and reduce maintenance times. Visual inspection is highly influenced by the human factor due to the working conditions. Image processing supported by vision systems offers high advantages reducing times, being the software and processing algorithms, which generates added value. In this paper, a novel method for wind turbines blades damages analysis is presented using image processing and a classifier based on dimensional features. The image acquisition is performed using a reflex camera with a telephoto and geo-location enabled. The faults analyzed include cracks, edge erosion, and electric discharge

Mathematical Modelling and Identification of a Quadrotor

Motivated by the important growth of VTOL vehicles research such as quadrotors and to a small extent autonomous flight, a quadrotor dynamical model is presented in this work. The purpose of this study is to get a better understanding of its flight dynamics. It is an underactuated system. So, a simplified and clear model is needed to implement controllers on these kind of unmanned aerial systems. In addition, a computational tool is used for validation purposes. For future works embedded or intelligent control systems can be developed to control them. Gyroscopic and some aerodynamics effects are neglected