3 research outputs found
Cdse/zns Quantum Dots Doped Microstructured Plastic Optical Fibres (mpofs) For Visible Spectra Amplification In The Green Window
No full textThis paper reports the transmission and fluorescence measurements of star-type PMMA mPOFs doped with CdSe/ZnS quantum-dots. The latter shows absorption at 509 nm and fluorescence at 529 nm wavelengths when diluted in toluene. Such mPOFs are intended to be a visible optical amplifier media in the 520 nm wavelength channel of PMMA POF links. The expected fluorescence emission is quite different of ~555 nm as measured with the doped mPOFs.151155Knowledge Development for POF,POF Application Center,Sojitz Corporation,Hamamatsu Photonics,OptogearZiemann, O., Krauser, J., Zamzow, P.E., Daum, W., POF Handbook - Optical Short Range Transmission Systems (2008), (2nd ed., Springer: Berlin)Kuzyk, M.G., Polymer Fiber Optics: Materials, Physics and Applications (2007), chapter 6, (Taylor & Francis)Technical Bulletin (2009), TBCDG0914PC33-01, Attenuation, PFU-CD1001-22-E and PMU-CD1001-22-E, July 14, Toray IndustriesWeinert, A., Plastic Optical Fibers: Principles, Components and Installation (1999), p. 40. , (Siemens)Ribeiro, R.M., Barbero, A.P.L., Medeiros, D.S.V., Ruas, P.H.D., Barbosa, L.C., Chillcce, E.F., Gonzáles, R.E.R., CdSe/ZnS Quantum Dots Doped Photonic Plastic Optical Fiber for Visible Spectra Amplification (2010), Proceedings of 19th ICPOF, October 19-21, Yokohama, JapanChillcce, E.F., Faustino, W.M., Jacob, G.J., Rodriguez, E., Cesar, C.L., Barbosa, L.C., Europium-doped optical fibers used as radiation sensors (2007), Proceedings of SPIE Newsroom, 20 MayEvident Technologies http//www.evidenttech.comYu, H.C.Y., Argyros, A., Leon-saval, S.G., Barton, G., Characterisation of quantum dot photoluminescence in polymer optical fibres (2009), Proceedings of 18th ICPOF, September 9-11, Sydney, Australia, paper S2_2
Cost Model for Manufacturing of a Girder for a Wind Turbine Blade
No full textWind energy has a longstanding reputation in making daily activities possible for mankind. Whereas in the past wind was used for propelling ships or for milling grain using wind mills, nowadays its market is growing towards the application of wind turbines, generating electricity in a sustainable manner. The growth in the wind energy market is more and more directed towards offshore wind. The trend here is installation of wind turbines with large rated power, leading to future turbines with rated power >5MW. For these turbines longer blades are required. Most blades are produced using glass fiber-epoxy. However, glass fiber has its limitations related to its stiffness. As the blades become larger, so does the tip deflection. In order to comply with the mechanical requirements of the blades, the usage of glass fiber is stretched to its limits and economically the usage might become less costefficient. To be still able to manufacture the larger blades, the focus is now set on a different reinforcement material: carbon fiber. Carbon fiber has better mechanical properties compared to glass fiber, but on the downside carbon fiber is more expensive. Therefore, for the switch from glass fiber to carbon fiber the economic picture should also be drawn. This is the focus of this thesis. This thesis focuses on the manufacturing cost of a girder that is manufactured using any of the three methods: vacuum infusion of glass fiber, vacuum infusion of carbon fiber and the prepreg process using carbon fiber as reinforcement material. The process of vacuum infusion of glass fiber is used as a reference in order to estimate the cost of the other two methods. This is done, as this process is used by Suzlon Energy in manufacturing wind turbine blades. The vacuum infusion of carbon fiber is the next method that will be assessed as this method can be seen as the next logical step. Simply said, this method can be applied by only changing the reinforcement material in the vacuum infusion process, so the change in the usage of reinforcement material is in this case the smallest as the manufacturing process remains the same. The choice for the prepreg method is that this method is thought to be a good alternative for manufacturing the blade instead of the vacuum infusion process. In a way it completes the picture of material switch. The aim of this thesis is twofold. On the one hand a cost model for the manufacturing of a girder using any of the three mentioned methods, i.e. vacuum infusion of glass fiber, vacuum infusion of carbon fiber and the prepreg process using carbon fiber as reinforcement material, is developed. On the other hand this model is used to determine which process, from an economical point of view, is favorable. The comparison of the three cost models is based on two criteria: manufacturing cost and manufacturing time. It is observed that the prepreg process is both more expensive and manufacturing takes longer compared to the vacuum infusion process of either glass fiber or carbon fiber. Focusing on the infusion process it is observed that there is a small difference in cost for infusion of glass fiber or infusion of carbon fiber. The trend shows is that for small blade lengths infusion of carbon fiber is slightly more expensive than infusion of glass fiber, however for larger blades the opposite becomes the case. Focusing on the manufacturing time it is observed that glass fiber infusion takes significantly more time compared to carbon fiber infusion. Therefore, it is concluded that the switch from glass fiber to carbon fiber is economically justified. However, this is only the case when the manufacturing process used is vacuum infusion of carbon fiber, rather than the use of carbon fiber in the prepreg process.Applied SciencesSustainable Energy Technolog
Communication protocols evaluation for a wireless rainfall monitoring network in an urban area
No full textRainfall monitoring networks are key elements for the development of alerts and prediction models for communities at risk of flooding during high intensity rainfall events. Currently, most of these networks send the precipitation measurement to a data center in real-time using wireless communication protocols, avoiding travel to the measurement site. An Early Warning System (EWS) for pluvial flash floods developed in Barranquilla (Colombia), used the GPRS protocol to send rain gauge data in real-time to a web server for further processing; however, this protocol has a high consumption of energy and also high maintenance costs. This article carried out an evaluation in terms of link budget, link profile, energy consumption and devices costs of three low-power wireless communication protocols, Zigbee, LoRaWAN and Sigfox, to determine which one is the most suitable for the EWS of the city of Barranquilla. To perform the evaluation, a wireless sensor network was designed and characterized for Zigbee and LoRaWAN with Radio Mobile tool taking into account the measurement points implemented with GPRS network. The evaluation included the power consumption of Zigbee, LoRaWAN and Sigfox. From the results of simulations, LoRaWAN and Zigbee network has similar radio signal received and the LoRaWAN network obtains the least losses per path. As for power consumption, the LoRaWAN devices has the lowest energy consumption, as well as, the LoRaWAN network sensor nodes are cheaper. Finally, the protocol with the best general performance was LoRAWAN, since complies with the communication, consumption and cost requirements
