Wind Resource Assessment on Puna Island

Puna Island, located in the Pacific Ocean off the southern coast of Ecuador, has a population of approximately 3344 inhabitants. However, not all inhabitants have access to electricity, which is largely supplied by diesel generators. Therefore, to identify a renewable, sustainable, environmentally friendly and low-cost alternative, a 40-m-high anemometer tower was installed for wind resource assessment and to determine the possibility of generating electricity from wind energy. Based on mathematical models for electricity generation from wind energy, data were analyzed using the software Windographer and WAsP, to determine a long-term wind speed of 4.8 m/s and a mean wind power density of 272 W/m(2). By simulating the use of a 3.3-MW wind turbine, we demonstrated that as much as 800 kWh could be generated during the hours when the wind reaches its highest speed. In addition to demonstrating the technical feasibility of meeting the electricity demands of Puna Island through wind power, this study exemplifies a method that can be used for wind resource assessment in any location

An Alternative Method To Prepare Cofe2o4 Thin Films

The sol-gel method has been utilized to prepare cobalt ferrite thin films using coconut water as a solvent. The magnetic properties of the thin films were investigated with a Quantum Design SQUID magnetometer. These films annealed up to 700 °C have a single phase spinel structure with no significant difference between their magnetic properties for external fields applied parallel or perpendicular to the planes of substrates. Moderate saturation magnetization and high coercivity have been found.2201413415Valenzuela, R., (1994) Magnetic Ceramics, , Cambridge University Press, CambridgeOkuno, S.N., Hashimoto, S., Inomata, K., (1992) J. Appl. Phys., 71, p. 5926Dorsey, P.C., Lubitz, P., Chrisey, D.B., Horowitz, J.S., (1996) J. Appl. Phys., 79, p. 6338Lee, J.-G., Lee, H.M., Kim, C.S., Oh, Y.-J., (1998) J. Magn. Magn. Mater., 177-181, p. 900Roy, R.W., Etzold, K.F., Cuomo, J.J., (1992) Mater. Res. Soc. Symp. Proc., 200, p. 179Luborsky, F.E., (1961) J. Appl. Phys., 32, pp. 171

2014 19th Symposium on Image, Signal Processing and Artificial Vision, STSIVA 2014

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Efectos de la presión hidrostática sobre la recombinación electrón-hueco en pozos cuánticos de GaAs-(Ga,Al)As

Usando la aproximación de masa efectiva se ha calculado la energía para los primeros estados ligados de electrón y hueco en pozos cuánticos de GaAs-(Ga,Al)As bajo los efectos de presión atmosférica e hidrostática. Los resultados para la diferencia de energías del par electrón-hueco en función de la presión para diferentes anchos de pozo cuántico describen razonablemente bien los resultados experimentales del coeficiente de presión para la fotoluminiscencia en pozos cuánticos de GaAs-(Ga,Al)As

Unique Coordination of Copper in Hexacyanometallates

Within divalent transition metals hexacyanometallates (III) the copper (2+) salts show unique features. To the copper (2+) salts correspond the shortest unit cell edges, the highest (CN) vibration frequencies, the lowest hydration degree and dehydration temperatures, the lowest Mössbauer isomer shift value, and the strongest magnetic exchange interaction (J) between the metal centers. Such unique features were attributed to a particularly strong bond of the copper atom to the N ends of the CN groups. The driving force for such behaviour was ascribed to a combined effect where the copper (2+) shows a high ability to receive electrons in its 3d hole favouring an electronic configuration close to 3d10 and the CN group complements such ability donating electrons through its 5 orbital which has certain anti-bonding character. This hypothesis is supported by the obtained structural and spectroscopic data. The occurrence of a cooperative Jahn–Teller effect in this family of materials was discarded. In the pseudo-octahedral coordination for the copper (2+) atom the eg orbital degeneration is initially removed. The collected EPR spectra are characteristic of a cubic environment (isotropic g-values). Analogue evidence was obtained from high resolution X-ray powder patterns recorded in the 12–300 K temperature range. All the patterns correspond to a cubic unit cell

Magnetic And Structural Properties Of Cofe2 O4 Thin Films Synthesized Via A Sol-gel Process

Using a sol-gel process having the coconut water as a precursor of organic chain, we synthesized thin films of cobalt ferrite. The films were characterized by using a SQUID magnetometer, an X-ray diffractometer, an X-ray spectrophotometer, Mössbauer spectroscopy and atomic force microscope. Co ferrite films annealed at 500°C for 2 h show grain sizes between 10 and 20 nm, grown as single-phase spinel structure and exhibit high coercivity and a moderate saturation magnetization (above 30kOe). © 2001 Elsevier Science B.V. All rights reserved.226-230PART II14241425Murdock, E.S., (1992) IEEE Trans. Magn., 28, p. 3078Valenzuela, R., (1994) Magnetic Ceramics, , Cambridge University Press, CambridgeOkuno, S.N., (1992) Appl. Phys., 71, p. 5926Naoe, M., Matsushita, N., (1996) J. Magn. Magn. Mater., 155, p. 216Matsushita, N., (1992) IEEE Trans. Magn., 28, p. 3108Dorsey, P.C., (1996) J. Appl. Phys., 79, p. 6338Cheng, F., (1998) Solid. State Commun., 107, p. 471Lee, J.-G., (1998) J. Appl. Phys., 84, p. 2801Macêdo, M.A., Patent Pending. 9804719-1/BRDos S Duque, J.G., Macêdo, M.A., Moreno, N.O., (2000) Phys. Stat. Sol. B, 220, p. 413Blaskov, V., (1996) J. Magn. Magn. Mater., 162, p. 33