Assessment of the Sustainability of Extensive Livestock Farms on the Common Grasslands of the Natural Park Sierra de Grazalema

The communal pastures of the Natural Park Sierra de Grazalema are grazed by a total of 23 extensive herds, of which 75% are certified as organic, although only 39% are subsidized for being organic. In a previous research work, these farms were characterized and classified into four typologies: group 1 (farms of intermediate size and without sheep), group 2 (large and very extensive farms), group 3 (farms with sheep suitable for both meat and milk) and group 4 (farms with dairy goat milk and without cattle). In this article, the sustainability of these farms is evaluated and compared based on their organic orientation (whether they are organic or conventional) and their typology (the four typologies indicated), as a tool for decision-making in the management of this natural protected area. To do so, 49 sustainability indexes have been generated, grouped into five attributes: adaptability, self-management, equity, stability, and productivity. The results indicate that, at the global level, there are no significant differences in sustainability between the organic and conventional farms studied. In contrast, depending on the typologies, the results indicate that group 3 is the most sustainable, followed by groups 1 and 4, with group 2 being the one with the lowest level of sustainability. Taking into account that there are a reduced number of herds grazing in this natural park, it is essential to solve the weaknesses of these farms in order to guarantee that they continue to maintain environmental equilibrium in the grasslands

La comunicación en las sedes webs de las universidades a distancia españolas

Esta investigación analiza la comunicación de las universidades españolas a distancia en sus sedes webs. En los últimos años este tipo de universidades se han multiplicado por cuatro. Hoy en día, las sedes webs de las universidades españolas online se ha convertido en una herramienta primordial para comunicar y atraer a públicos potenciales. Es más, en este tipo de universidades la sede web es el medio por el que los alumnos conocen y establecen una relación con la universidad. El fin de este estudio es profundizar en la forma en que las universidades a distancia se comunican a través de sus sedes webs. Para ello, este trabajo ha utilizado el análisis de contenidos con el fin de estudiar las sedes webs de las universidades españolas a distancia.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Simulation Platform for Coordinated Charging of Electric Vehicles

EMERALD is a project funded by the European Commission under the FP7 program focusing on energy use optimization on the integration of the FEVs into the transport and energy infrastructure. Between the objectives of EMERALD, enhanced power demand prediction and power flow support management system uses the power flow demand simulation platform considered in this paper. The power flow demand simulation platform is a software tool that defines the estimation of FEVs power demand according to different conditions as, arrival and departure curves, the estimation of power production based on renewable energy sources and the electricity cost. The tool coordinates scheduling for charging of FEVs in order to minimize the recharging cost, considering the energy balance between the generation and demand powerEuropean commission's FP

Cooperative Simulation Tool with the Energy Management System for the Storage of Electricity Surplus through Hydrogen

The INGRID project aims at demonstrating the effective usage of safe, high-density, solid-state hydrogen storage systems for power supply and demand balancing within active power distribution grids with high penetration of intermittent Distributed Generation (Renewable Energy Sources in particular.) The INGRID simulator is divided in two main blocks: the first one represents the Energy Management System, the second one includes the Green Energy Storage System (water electrolyzer, hydrogen solid-storage systems and fuel cell) created to simulate the plant. This paper describes the modules of INGRID simulator and the transient responses of the system for an energy management system virtual according to the power prediction of renewable energy sources, hydrogen demand and the power demand of electric vehiclesEuropean Commission's FP

A New Cutting Device Design to Study the Orthogonal Cutting of CFRP Laminates at Different Cutting Speeds

[EN] Carbon Fiber-reinforced plastics (CFRPs) are widely used in the aerospace industry due to their highly mechanical properties and low density. Most of these materials are used in high-risk structures, where the damage caused by machining must be controlled and minimized. The optimization of these processes is still a challenge in the industry. In this work, a special cutting device, which allows for orthogonal cutting tests, with a linear displacement at a wide range of constant cutting speeds, has been developed by the authors. This paper describes the developed cutting device and its application to analyze the influence of tool geometry and cutting parameters on the material damage caused by the orthogonal cutting of a thick multidirectional CFRP laminate. The results show that a more robust geometry (higher cutting edge radius and lower rake angle) and higher feed cause an increase in the thrust force of a cutting tool, causing burrs and delamination damage. By reducing the cutting speed, the components with a higher machining force were also observed to have less surface integrity control.This research was funded by the Ministry of economy, Industry and Competitiveness and FEDER (grant number: DPI2017-89197-C2-1-R).Criado, V.; Feito-Sánchez, N.; Cantero Guisández, J.; Díaz-Álvarez, J. (2019). A New Cutting Device Design to Study the Orthogonal Cutting of CFRP Laminates at Different Cutting Speeds. Materials. 12(24):1-13. https://doi.org/10.3390/ma12244074S1131224Che, D., Saxena, I., Han, P., Guo, P., & Ehmann, K. F. (2014). Machining of Carbon Fiber Reinforced Plastics/Polymers: A Literature Review. Journal of Manufacturing Science and Engineering, 136(3). doi:10.1115/1.4026526Vigneshwaran, S., Uthayakumar, M., & Arumugaprabu, V. (2018). Review on Machinability of Fiber Reinforced Polymers: A Drilling Approach. Silicon, 10(5), 2295-2305. doi:10.1007/s12633-018-9764-9Panchagnula, K. K., & Palaniyandi, K. (2018). Drilling on fiber reinforced polymer/nanopolymer composite laminates: a review. Journal of Materials Research and Technology, 7(2), 180-189. doi:10.1016/j.jmrt.2017.06.003Wang, F., Yin, J., Ma, J., & Niu, B. (2018). Heat partition in dry orthogonal cutting of unidirectional CFRP composite laminates. Composite Structures, 197, 28-38. doi:10.1016/j.compstruct.2018.05.040Fernández-Pérez, J., Cantero, J. L., Díaz-Álvarez, J., & Miguélez, M. H. (2017). Influence of cutting parameters on tool wear and hole quality in composite aerospace components drilling. Composite Structures, 178, 157-161. doi:10.1016/j.compstruct.2017.06.043Feito, N., Díaz-Álvarez, J., López-Puente, J., & Miguelez, M. H. (2018). Experimental and numerical analysis of step drill bit performance when drilling woven CFRPs. Composite Structures, 184, 1147-1155. doi:10.1016/j.compstruct.2017.10.061López de Lacalle, L. N., & Lamikiz, A. (2009). Milling of Carbon Fiber Reinforced Plastics. Advanced Materials Research, 83-86, 49-55. doi:10.4028/www.scientific.net/amr.83-86.49Feito, N., Diaz-Álvarez, A., Cantero, J. L., Rodríguez-Millán, M., & Miguélez, H. (2015). Experimental analysis of special tool geometries when drilling woven and multidirectional CFRPs. Journal of Reinforced Plastics and Composites, 35(1), 33-55. doi:10.1177/0731684415612931Henerichs, M., Voß, R., Kuster, F., & Wegener, K. (2015). Machining of carbon fiber reinforced plastics: Influence of tool geometry and fiber orientation on the machining forces. CIRP Journal of Manufacturing Science and Technology, 9, 136-145. doi:10.1016/j.cirpj.2014.11.002Yan, X., Reiner, J., Bacca, M., Altintas, Y., & Vaziri, R. (2019). A study of energy dissipating mechanisms in orthogonal cutting of UD-CFRP composites. Composite Structures, 220, 460-472. doi:10.1016/j.compstruct.2019.03.090Lopresto, V., Langella, A., Caprino, G., Durante, M., & Santo, L. (2017). Conventional Orthogonal Cutting Machining on Unidirectional Fibre Reinforced Plastics. Procedia CIRP, 62, 9-14. doi:10.1016/j.procir.2016.07.036Santiuste, C., Olmedo, A., Soldani, X., & Miguélez, H. (2012). Delamination prediction in orthogonal machining of carbon long fiber-reinforced polymer composites. Journal of Reinforced Plastics and Composites, 31(13), 875-885. doi:10.1177/0731684412444654ZITOUNE, R., COLLOMBET, F., LACHAUD, F., PIQUET, R., & PASQUET, P. (2005). Experiment?calculation comparison of the cutting conditions representative of the long fiber composite drilling phase. Composites Science and Technology, 65(3-4), 455-466. doi:10.1016/j.compscitech.2004.09.028Rao, G. V. G., Mahajan, P., & Bhatnagar, N. (2007). Micro-mechanical modeling of machining of FRP composites – Cutting force analysis. Composites Science and Technology, 67(3-4), 579-593. doi:10.1016/j.compscitech.2006.08.010Wang, H., Chang, L., Mai, Y.-W., Ye, L., & Williams, J. G. (2018). An experimental study of orthogonal cutting mechanisms for epoxies with two different crosslink densities. International Journal of Machine Tools and Manufacture, 124, 117-125. doi:10.1016/j.ijmachtools.2017.10.003Lopresto, V., Caggiano, A., & Teti, R. (2016). High Performance Cutting of Fibre Reinforced Plastic Composite Materials. Procedia CIRP, 46, 71-82. doi:10.1016/j.procir.2016.05.079Voss, R., Seeholzer, L., Kuster, F., & Wegener, K. (2019). Analytical force model for orthogonal machining of unidirectional carbon fibre reinforced polymers (CFRP) as a function of the fibre orientation. Journal of Materials Processing Technology, 263, 440-469. doi:10.1016/j.jmatprotec.2018.08.001Seeholzer, L., Voss, R., Grossenbacher, F., Kuster, F., & Wegener, K. (2018). Fundamental analysis of the cutting edge micro-geometry in orthogonal machining of unidirectional Carbon Fibre Reinforced Plastics (CFRP). Procedia CIRP, 77, 379-382. doi:10.1016/j.procir.2018.09.040Feito, N., Diaz-Álvarez, J., López-Puente, J., & Miguelez, M. H. (2016). Numerical analysis of the influence of tool wear and special cutting geometry when drilling woven CFRPs. Composite Structures, 138, 285-294. doi:10.1016/j.compstruct.2015.11.065Cepero-Mejías, F., Curiel-Sosa, J. L., Zhang, C., & Phadnis, V. A. (2019). Effect of cutter geometry on machining induced damage in orthogonal cutting of UD polymer composites: FE study. Composite Structures, 214, 439-450. doi:10.1016/j.compstruct.2019.02.012Santiuste, C., Soldani, X., & Miguélez, M. H. (2010). Machining FEM model of long fiber composites for aeronautical components. Composite Structures, 92(3), 691-698. doi:10.1016/j.compstruct.2009.09.021Soldani, X., Santiuste, C., Muñoz-Sánchez, A., & Miguélez, M. H. (2011). Influence of tool geometry and numerical parameters when modeling orthogonal cutting of LFRP composites. Composites Part A: Applied Science and Manufacturing, 42(9), 1205-1216. doi:10.1016/j.compositesa.2011.04.023Iliescu, D., Gehin, D., Iordanoff, I., Girot, F., & Gutiérrez, M. E. (2010). A discrete element method for the simulation of CFRP cutting. Composites Science and Technology, 70(1), 73-80. doi:10.1016/j.compscitech.2009.09.007Wang, D., He, X., Xu, Z., Jiao, W., Yang, F., Jiang, L., … Wang, R. (2017). Study on Damage Evaluation and Machinability of UD-CFRP for the Orthogonal Cutting Operation Using Scanning Acoustic Microscopy and the Finite Element Method. Materials, 10(2), 204. doi:10.3390/ma10020204Sahraie Jahromi, A., & Bahr, B. (2010). An analytical method for predicting cutting forces in orthogonal machining of unidirectional composites. Composites Science and Technology, 70(16), 2290-2297. doi:10.1016/j.compscitech.2010.09.005Wang, D. H., Ramulu, M., & Arola, D. (1995). Orthogonal cutting mechanisms of graphite/epoxy composite. Part I: unidirectional laminate. International Journal of Machine Tools and Manufacture, 35(12), 1623-1638. doi:10.1016/0890-6955(95)00014-oLi, H., Qin, X., He, G., Jin, Y., Sun, D., & Price, M. (2015). Investigation of chip formation and fracture toughness in orthogonal cutting of UD-CFRP. The International Journal of Advanced Manufacturing Technology, 82(5-8), 1079-1088. doi:10.1007/s00170-015-7471-xVoss, R., Seeholzer, L., Kuster, F., & Wegener, K. (2017). Influence of fibre orientation, tool geometry and process parameters on surface quality in milling of CFRP. CIRP Journal of Manufacturing Science and Technology, 18, 75-91. doi:10.1016/j.cirpj.2016.10.002Nayak, D., Bhatnagar, N., & Mahajan, P. (2005). MACHINING STUDIES OF UNI-DIRECTIONAL GLASS FIBER REINFORCED PLASTIC (UD-GFRP) COMPOSITES PART 1: EFFECT OF GEOMETRICAL AND PROCESS PARAMETERS. Machining Science and Technology, 9(4), 481-501. doi:10.1080/10910340500398167An, Q., Cai, C., Cai, X., & Chen, M. (2019). Experimental investigation on the cutting mechanism and surface generation in orthogonal cutting of UD-CFRP laminates. Composite Structures, 230, 111441. doi:10.1016/j.compstruct.2019.111441Bhatnagar, N., Nayak, D., Singh, I., Chouhan, H., & Mahajan, P. (2004). Determination of Machining-Induced Damage Characteristics of Fiber Reinforced Plastic Composite Laminates. Materials and Manufacturing Processes, 19(6), 1009-1023. doi:10.1081/amp-200035177Wang, X., Kwon, P. Y., Sturtevant, C., Kim, D. (Dae-W., & Lantrip, J. (2013). Tool wear of coated drills in drilling CFRP. Journal of Manufacturing Processes, 15(1), 127-135. doi:10.1016/j.jmapro.2012.09.019Fernández-Pérez, J., Cantero, J. L., Álvarez, J. D., & Miguélez, M. H. (2017). Composite Fiber Reinforced Plastic one-shoot drilling: Quality inspection assessment and tool wear evaluation. Procedia Manufacturing, 13, 139-145. doi:10.1016/j.promfg.2017.09.021Sorrentino, L., Turchetta, S., Colella, L., & Bellini, C. (2016). Analysis of Thermal Damage in FRP Drilling. Procedia Engineering, 167, 206-215. doi:10.1016/j.proeng.2016.11.689Díaz-Álvarez, J., Criado, V., Miguélez, H., & Cantero, J. (2018). PCBN Performance in High Speed Finishing Turning of Inconel 718. Metals, 8(8), 582. doi:10.3390/met8080582Su, Y. (2019). Effect of the cutting speed on the cutting mechanism in machining CFRP. Composite Structures, 220, 662-676. doi:10.1016/j.compstruct.2019.04.052Wang, X. M., & Zhang, L. C. (2003). An experimental investigation into the orthogonal cutting of unidirectional fibre reinforced plastics. International Journal of Machine Tools and Manufacture, 43(10), 1015-1022. doi:10.1016/s0890-6955(03)00090-7Xu, J., El Mansori, M., Voisin, J., Chen, M., & Ren, F. (2019). On the interpretation of drilling CFRP/Ti6Al4V stacks using the orthogonal cutting method: Chip removal mode and subsurface damage formation. Journal of Manufacturing Processes, 44, 435-447. doi:10.1016/j.jmapro.2019.05.05

A Typological Characterization of Organic Livestock Farms in the Natural Park Sierra de Grazalema Based on Technical and Economic Variables

This paper describes the typological characterization of the Natural Park Sierra de Grazalema (NPSG) livestock farms using its communal pastures (N = 23, 100% of population) in order to study their sustainability from 160 technical, economic and social variables (from direct on-farm data collection). A principal components analysis (PCA) produced four principal components related to size, livestock species, main productions and intensification level, explaining 73.6% of the variance. The subsequent cluster analysis classified the farms into four groups: C1 (medium size farms without sheep), C2 (large size and very extensive farms), C3 (farms with multipurpose sheep) and C4 (farms with dairy goat and without cattle). Forty-eight-point-seven percent of the surface was registered as organic but none of the farms’ commercialized products were organic. C2 and C3 (both having three ruminant species) are those farms that have more economic differences, the former generating the lowest profit, and the latter generating the highest; however, there is a risk to grasslands conservation from the current tendency that leads dairy farms to rapid intensification. Nevertheless, the very extensive farms are the most interesting for NPSG conservation and the administration should help to maintain the profitability of this sustainable traditional activity, which is necessary to conserve communal pastures

Density and reproductive characteristics of female brown bears in the Cantabrian Mountains, NW Spain

Here we present annual nearest-neighbour distances (as a proxy of density) between females with cubs-of-the-year (hereafter FCOY) and reproductive characteristics of brown bears Ursus arctos in the Cantabrian Mountains (NW Spain), from 1989 to 2017. FCOY nearest-neighbour distances and reproduction parameters of 19 focal females followed over several consecutive years (from 2004 to 2017) were obtained from bears inhabiting the western sector of the Cantabrian Mountains, where most of the bear population resides. In contrast, general reproductive characteristics were studied in the whole Cantabrian Mountains (western and eastern sectors together) on a sample of 362 litter sizes and 695 cubs. Mean nearest-neighbour distance between FCOY was 2559 ± 1222 m (range = 1305–4757 m). Mean litter size was significantly larger in the west (1.8 ± 0.2 cubs) than in the east (1.3 ± 0.6 cubs). Mean litter size for the whole of the Cantabrian Mountains was 1.6 ± 0.3 cubs. Litter sizes of one, two and three cubs represented 33.4, 56.1 and 10.5% of observed family groups, respectively. Interannual variations in litter size were not significant for both the western and the eastern areas. Mean cub mortality was 0.2 ± 0.5 cubs and did not vary among years. Cub mortality per litter size was 3.9% for one cub, 69.2% for two cubs and 26.9% for three cubs. Mean reproductive rate of the 19 focal females was 1.5 ± 0.6 cubs (n = 58 litters). Litter size of focal FCOY did not differ from the litter size obtained from systematic observations in the whole Cantabrian Mountains. During this period, cub mortality occurred in 24.1% of the 58 litters. Females usually bred every second year (average litter interval = 2.2 years). The estimated reproductive rate for the bear population was 0.7 young born/year/reproductive adult female

El efecto del humo de sílice y el metacaolín en el proceso de envejecimiento de los morteros de cemento reforzados con fibras de vidrio (GRC)

The deterioration of the mechanical properties of glassfibre reinforced concrete (GRC) over time rules out the use of this material in load-bearing structures. While one possible solution to this problem is the addition of pozzolans or metakaolin to the cement mortar, the amounts needed to ensure GRC integrity raise its price to non-competitive levels. Experimental research has been conducted to analyze whether the addition of small amounts of silica fume or metakaolin can prevent or mitigate the ageing issue. Unfortunately, the findings indicate that the addition of small proportions of metakaolin or silica fume to GRC are ineffective in improving its long-term performance.Para el uso del mortero de cemento reforzado con fibras de vidrio (GRC) en estructuras portantes se han de solucionar los problemas de reducción de las propiedades mecánicas que aparecen con el paso del tiempo. Estos problemas pueden ser solucionados mediante la adición de puzolanas o de metacaolín, a la pasta de mortero de cemento. Sin embargo, la cantidad de metacaolín que ha de ser añadida es elevada y el precio del GRC fabricado está fuera del mercado. Se ha realizado una campaña experimental que analiza si la adición de humo de sílice o de metacaolín en proporciones reducidas consigue evitar o paliar el problema del envejecimiento, que supone un freno al uso del GRC en elementos estructurales. Desgraciadamente, los resultados experimentales muestran que proporciones bajas de metacaolín o de humo de sílice no son efectivas para reducir el problema de pérdida de propiedades mecánicas

Dark Matter Subhalos in the Ursa Minor Dwarf Galaxy

Through numerical simulations, we study the dissolution timescale of the Ursa Minor cold stellar clump, due to the combination of phase-mixing and gravitational encounters with compact dark substructures in the halo of Ursa Minor. We compare two scenarios; one where the dark halo is made up by a smooth mass distribution of light particles and one where the halo contains 10% of its mass in the form of substructures (subhalos). In a smooth halo, the stellar clump survives for a Hubble time provided that the dark matter halo has a big core. In contrast, when the point-mass dark substructures are added, the clump survives barely for \sim 1.5 Gyr. These results suggest a strong test to the \Lambda-cold dark matter scenario at dwarf galaxy scale.Comment: accepted for publication in Ap

Prótesis de pirocarbono en fracturas complejas de cabeza de radio.

Presentamos los resultados de un estudio observacional retrospectivo sobre 23 casos de fracturas complejas de cabeza de radio tratadas mediante la implantación de una prótesis cabeza radio de pircocarbono (Mo - Pyc). La distribución por sexos fue 10 hombres y 13 mujeres, y la edad media de 54 años. El seguimiento medio fue de 70 meses (48-93 meses). La principal causa fue una fractura de cabeza de radio no reconstruible con inestabilidad asociada de codo. La evaluación clínica se realizó con la Mayo Elbow Performance Score (MEPS). Radiográficamen - te se valoró la congruencia articular, el tamaño de la prótesis, la radiolucencia periprotésica, la osificación heterotópica y la osteoartritis. Al final del seguimiento la media de la escale MEPS fue 82/100, con 84 % resultados de excelentes y buenos. La flexión media fue de 130º, extensión -30º, pronación 76º y supinación 77º. La estabilidad del codo fue buena en todos los casos y no observamos migración proximal del radio. Observamos radiolucencia alrededor del vástago en 5 pacientes, pero sin aparente repercusión clínica. Las complicaciones fueron una paresia del nervio interóseo posterior con recuperación funcional al cabo de 11 semanas, 2 pacientes presentaron "overstuffing" con subluxación posterior asociada que necesitó realizar exéresis de la cabeza y una osificación heterotópica con repercu - sión sobre el balance articular que necesitó 2 cirugías, todos ellos con resultados clínicos aceptables. Los resultados son alentadores.The authors present the results of a retrospective observational study of 23 cases of a complex radial head fractures treated by pyrocarbon radial head prosthesis (MoPyc). This modular radial head prosthesis is compo - sed of a cementless titanium stem and a 15º angulated neck. The gender distribution was 10 men and 13 women, ave - rage age 54 years. The mean follow-up was 70 months (48-93 months). The main etiology was a radial head fracture with elbow instability. Clinical evaluation was performed using the Mayo Elbow Performance Score (MEPS). Was assessed radiographically joint congruity, the size of the prosthesis, periprosthetic radiolucency, heterotopic ossifica - tion and osteoarthritis. At follow-up, the MEPS average was 82/100, with 84% of good and excellent results. Elbow flexion averaged 130º, extension -30º, pronation 76º and supination 77º. Elbow stability was good in all the cases, and no proximal migration of the radius occurred. Asymptomatic bone lucencies were found in five cases around the stem. Complications included paresis of the posterior interosseous nerve with functional recovery after 11 weeks, 2 patients had "overstuffing" associated with posterior subluxation and they need to perform excision of the head and one heterotopic ossification with articular impact on balance that needs two surgeries, all of them with acceptable clinical results. The preliminary results are encouragin