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{"references": ["European Wind Energy Association, EU energy policy after 2020,\nwww.ewea.org, 2011.", "M. Raciti Castelli, G. Grandi and E. Benini, \"Numerical Analysis of the\nPerformance of the DU91-W2-250 Airfoil for Straight-Bladed Vertical-\nAxis Wind Turbine Application\", submitted to ICAFM 2012:\nInternational Conference on Advances in Fluid Mechanics, Florence\n(Italy), February 28-29, 2012.", "W.A. Timmer, W. A. and R. P. J. O. M. van Rooij, \"Summary of the\ndelft university wind turbine dedicated airfoils\", AIAA-2003-0352.", "W.A. Timmer, W. A. and R. P. J. O. M. van Rooij, \"Design of airfoils\nfor wind turbine blades\", DUWIND, section Wind Energy, Faculty\nCiTG, 03 May, 2004.", "G. Lombardi, M. V. Salvetti and D. Pinelli, \"Numerical Evaluation of\nAirfoil Friction Drag\", J. Aircraft, Vol. 37, No. 2, pp. 354-356, 2000.", "Y. Lian and W. Shai, \"Laminar-Turbulent Transition of a Low Reynolds\nNumber Rigid or Flexible Airfoil\", AIAA Journal, Vol. 45, No. 7, July\n2007, pp. 1501-1513.", "F. R. Menter, R. B. Langrty, S. R. Likki, Y. B. Suzen, P. G. Huang and\nS. V\u00f6lker, \"A Correlation-Based Transition Model Using Local\nVariables - Part I: Model Formulation\", Journal of Turbomachinery,\nVolume 128, Issue 3, pp. 413-422, 2006.", "F. R. Menter, R. B. Langrty, S. R. Likki, Y. B. Suzen, P. G. Huang and\nS. V\u00f6lker, \"A Correlation-Based Transition Model Using Local\nVariables - Part II: Test Cases and Industrial Applications\", Journal of\nTurbomachinery, Volume 128, Issue 3, pp. 423-434, 2006.", "E. Benini and R. Ponza, \"Laminar to Turbulent Boundary Layer\nTransition Investigation on a Supercritical Airfoil Using the \u256c\u2502-\u256c\u00a9\nTransitional Model\", 40th Fluid Dynamics Conference and Exhibit, 28\nJune - 1 July 2010, Chicago, Illinois, AIAA 2010-4289.\n[10] S. Hosseinverdi and M. Boroomand, \"Prediction of Laminar-Turbulent\nTransitional Flow over Single and Two-Element Airfoils\", 40th Fluid\nDynamics Conference and Exhibit, 28 June - 1 July 2010, Chicago,\nIllinois, AIAA 2010-4290.\n[11] L. Yuhong and L. Congming, \"A numerical simulation of flow around a\nwind turbine airfoil based on transition model\", WNEC 2009: World\nNon-Grid-Connected Wind Power and Energy Conference, Nanjing\n(China), 24-26 Sept. 2009.\n[12] W.A. Timmer, W. A. and R. P. J. O. M. van Rooij, Aifoil DU91-W2-\n250 Coordinates and Measurements in Delft University 1.25x1.80 m\nLow-speed Wind tunnel, data provided by direct contact from the\nauthors.\n[13] ANSYS FLUENT 12.0-12.1 Documentation, Release 12.1 \u252c\u00ae ANSYS,\nInc. 2009-10-01.\n[14] J. Johansen, \"Prediction of Laminar/Turbulent Transition in Airfoil\nFlows\", Ris\u251c\u00a9 National Laboratory, Roskilde, Denmark, May 1997,\nRis\u251c\u00a9-R-987(EN).\n[15] M. Raciti Castelli, F. Garbo, E. Benini, \"Numerical investigation of\nlaminar to turbulent boundary layer transition on a NACA 0012 airfoil\nfor vertical-axis wind turbine applications\", Wind Engineering, Vol. 35,\nNo. 6, 2011, pp. 661-686."]} This paper presents a study of laminar to turbulent transition on a profile specifically designed for wind turbine blades, the DU91-W2-250, which belongs to a class of wind turbine dedicated airfoils, developed by Delft University of Technology. A comparison between the experimental behavior of the airfoil studied at Delft wind tunnel and the numerical predictions of the commercial CFD solver ANSYS FLUENT® has been performed. The prediction capabilities of the Spalart-Allmaras turbulence model and of the γ-θ Transitional model have been tested. A sensitivity analysis of the numerical results to the spatial domain discretization has also been performed using four different computational grids, which have been created using the mesher GAMBIT®. The comparison between experimental measurements and CFD results have allowed to determine the importance of the numerical prediction of the laminar to turbulent transition, in order not to overestimate airfoil friction drag due to a fully turbulent-regime flow computation.

{"references": ["S. Throp, \"Climate change challenges and opportunities. Special issue. CTA Spore, 2015.", "Intergovernmental Panel on Climate change (IPCC) Climate change: The Physical Science Basis (summary for policy), IPCC, and Geneva. 2007.", "A.M. Atolagbe, \"Architecture in Nigeria and the Practice for Sustainable Development: A Comparative education\" Nairobi, Kenya: ICRAF. 2002.", "D.M. Ranasingbe, Forestry Education and Global Change. A case study on the contribution of Forest study of Modern and Indigenous housing strategy. AARCHES Journal, vol. 2, no. 1, 61 - 65. 2008.", "C. U. Nwajiuba, and R.U Onyeneke, Effects of climate change on the agriculture of sub-Saharan Africa: Lessons from Southeast Rainforest zone of Nigeria. Paper presented at the 10th Global Conference on Business and Economics, St Hugh's College University Press. 2010.", "M. Yesuf, S. Difalce; T. Deressa; C. Ringler and G.Kohlin, The impact of climate and Adaptation on food Production in low income countries; Evidence from the Nile Basin, Ethiopia. International Food Policy Research Institute Discussion (IFPRI) Paper No. 00828. Environment and Production Technology Division, IFPRI, Washington D.C. 2008.", "L. Grace, Sustainable Agriculture: the basic. www.gracelinks.org 2016 Accessed on 20/09/2016.", "I.U Nwaiwu, et al., The effects of Climate Change on Agricultural Sustainability in Southeast Nigeria \u2013 Implications \tfor Food \tSecurity. Asian Journal of Agricultural Extension, Economic and Sociology, vol. 3. No 1, 23-26 2013.", "Nigerian Environmental Study and Action team (NEST). Triggering Rural-Urban Interactions to Cope with Climate\t Change: An adaptation Experiment in Aba and its Region, southeastern Nigeria, NEST, Ibadan, Nigeria, 2012.\n[10]\tR. Mendelsohn, Measuring the effect of climate change on Developing country Agriculture: Two Essays on climate change on Agriculture FAO Corporate DocumentRepository, www.fao.org/docrep 2000. Accessed on 16/08/2016.\n[11]\tW. Akpalu, R.M. Hassan and C.Ringler. Climate Variability and Maize Yeild in South Africa:Results from GME (generalized maximum entropy) and MELE (maximum entropy leuven estimator) methods. International Food Policy Research Institute (IFPRI) Discussion Paper No. 00843, Environment and Production Technology Division, IFPRI, Washinton D.C.\n[12]\tR.U.Onyeneke, Climate change and Crop farmers Adaptation measures in the Southeast Rainforest zone of Nigeria (unpublished) MSC Thesis. 2010.\n[13]\tS. Anderson, Climate change impacts on the progress towards and the sustainability of MDG achievement across Africa\". Report to the Africa Partnerships Forum, 2010.\n[14]\tJ.O. Munonye and C.S. Nwosu, Agricultural sustainability and\tEnvironmental Quality. Conference on International Journal of Arts and Sciences, 08(04): 57 -65. 2015.\n[15]\tB, Ronald, Farm Productive Practices http://www.farm.org/features/002/roland-bunch Accessed on 17/06/2016."]} Climate change has both negative and positive effects in agricultural production. For agriculture to be sustainable in adverse climate change condition, some natural measures are needed. The issue is to produce more food with available natural resources and reduce the contribution of agriculture to climate change. The study reviewed climate change and sustainable agriculture in southeast Nigeria. Data from the study were from secondary sources. Ten scientific papers were consulted and data for the review were collected from three. The objectives of the paper were as follows: to review the effect of climate change on one major arable crop in southeast Nigeria (yam; Dioscorea rotundata); evident of climate change impact and methods for sustainable agricultural production in adverse weather condition. Some climatic parameter as sunshine, relative humidity and rainfall have negative relationship with yam production and significant at 10% probability. Crop production was predicted to decline by 25% per hectare by 2060 while livestock production has increased the incidence of diseases and pathogens as the major effect to agriculture. Methods for sustainable agriculture and damage of natural resources by climate change were highlighted. Agriculture needs to be transformed as climate changes to enable the sector to be sustainable. There should be a policy in place to facilitate the integration of sustainability in Nigeria agriculture.

Today the energy storage systems are still encumbering, therefore it is useful to think about the optimization of a railgun system in order to achieve the best performance with the lowest energy input. In this paper, an optimal design method considering 5 parameters is proposed to improve the energy conversion efficiency of a simple railgun. In order to avoid costly trials, the field- circuit method is employed to analyze the operations of different structural railguns with different parameters respectively. And the orthogonal test approach is used to guide the simulation for choosing the better parameter combinations, as well reduce the calculation cost. The research shows that the proposed method gives a better result in the energy efficiency of the system. To improve the energy conversion efficiency of electromagnetic rail launchers, the selection of more parameters must be considered in the design stage, such as the width, height and length of rail, the distance between rail pair, and pulse forming inductance. However, the relationship between these parameters and energy conversion efficiency cannot be directly described by one mathematical expression. So optimization methods must be applied to conduct design. In this paper, a rail launcher with five parameters was optimized by using orthogonal test method. According to the arrangement of orthogonal table, the better parameters’ combination can be obtained through less calculation. Under the condition of different parameters’ value, field and circuit simulation analysis were made. The results show that the energy conversion efficiency of the system is increased by 71.9 % after parameters optimization.

A prototype ampere-class superconducting energy recovery linac (ERL) is under advanced construction at BNL. The ERL facility is comprised of a five-cell SC Linac plus a half-cell SC photo-injector RF electron gun, both operating at 703.75 MHz. The facility is designed for either a high-current mode of operation up to 0.5 A at 703.75 MHz or a high-bunch-charge mode of 5 nC at 10 MHz bunch frequency. The R facility serves a test bed for an envisioned electron-hadron collider, eRHIC. The high-current, high-charge operating parameters make effective higher-order-mode (HOM) damping mandatory, and requires to determination of HOM tolerances for a cavity upgrade. The niobium cavity has been tested at superconducting temperatures and has provided measured dipole shunt impedances for the estimate of a beam breakup instability. The facility will be assembled with a highly flexible lattice covering a vast operational parameter space for verification of the estimates and to serve as a test bed for the concepts directed at future projects. Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan

This abstract describes a project based, interdisciplinary course on applied superconductivity that was shared between four departments. The topic of the course was high temperature superconducting wind turbine generators. The students started by studying the problem at hand and then worked with mathematical modelling, small-scale prototype construction, and experimental testing. The course followed the CDIO ethos, where the students Conceived the problem at hand; Designed a solution; Implemented that solution both by construction and modeling; and finally Operated the constructed prototype and models.

{"references": ["B. C. Norman, \"Power Options for Wireless Sensor Networks,\" Proc. Proceedings 40th Annual 2006 International Carnahan Conference on Security Technology, 2006,.pp. 17-20.", "A. Abdelkefi, A. Alothman, and M. R. Hajj, \"Performance analysis and validation of thermoelectric energy harvesters,\" Smart Materials and Structures, vol. 22, no. 9, p. 095014, 2013.", "I. L.Cassidy, J. T. Scruggs, and S. Behrens, \"Design of electromagnetic energy harvesters for large-scale structural vibration applications,\" Proc. SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, SPIE, 2011, p. 11.", "M. Bryant, and E. Garcia, \"Modeling and testing of a novel aeroelastic flutter energy harvester,\" Journal of Vibration and Acoustics, vol. 133, no. 1, pp. 011010-011010-011011, 2011.", "L. A. Weinstein, M. R. Cacan, P. M. So, and P. K. Wright, \"Vortex shedding induced energy harvesting from piezoelectric materials in heating, ventilation and air conditioning flows,\" Smart Materials and Structures, vol. 21 no. 4, p. 045003, 2012.", "J. M. McCarthy, A. Deivasigamani, S. J. John, S. Watkins, F Coman, and P. Petersen, \"Downstream flow structures of a fluttering piezoelectric energy harvester,\" Experimental Thermal and Fluid Science, vol. 51, pp. 279-290, 2013.", "J. J. Allen, and A. J. Smits, \"Energy Harvesting Eel,\" Journal of Fluids and Structures, vol. 15, no. 3, pp. 629-640, 2001.", "S. Mittal, and V. Kumar, \"Vortex induced vibrations of a pair of cylinders at Reynolds number 1000,\" International Journal of Computational Fluid Dynamics, vol. 18, no. 7, pp. 601-614, 2004.", "J. Mizushima, and N. Suehiro, \"Instability and transition of flow past two tandem circular cylinders,\" Physics of Fluids, vol. 17, no. 10, p. 104107, 2005.\n[10]\tW. B. Hobbs, and D. L. Hu, \"Tree-inspired piezoelectric energy harvesting,\" Journal of Fluids and Structures, vol. 28, pp. 103-114, 2012\n[11]\tA. Abdelkefi, J. M. Scanlon, E. McDowell, and M. R. Hajj, \"Performance enhancement of piezoelectric energy harvesters from wake galloping,\" Applied Physics Letters, vol. 103, no. 3, p. 033903, 2013.\n[12]\tD. Guyomar, A. Badel, E. Lefeuvre, and C. Richard, \"Toward energy harvesting using active materials and conversion improvement by nonlinear processing,\" IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 52, no. 4, pp. 584-595, 2005.\n[13]\tE. Naudascher, and D. Rockwell, \"Oscillator-Model Approach To Theidentification And Assessment Offlow-Induced Vibrations In A System,\" Journal of Hydraulic Research, vol. 18 no. 1, pp. 59-82, 1980."]} This paper presents an experimental investigation for the characteristics of an energy harvesting device exploiting flow-induced vibration in a wind tunnel. A stationary bluff body is connected with a downstream tip body via an aluminium cantilever beam. Various lengths of aluminium cantilever beam and different shapes of downstream tip body are considered. The results show that the characteristics of the energy harvester’s vibration depend on both the length of the aluminium cantilever beam and the shape of the downstream tip body. The highest ratio between vibration amplitude and bluff body diameter was found to be 1.39 for an energy harvester with a symmetrical triangular tip body and L/D1 = 5 at 9.8 m/s of flow speed (Re = 20077). Using this configuration, the electrical energy was extracted with a polyvinylidene fluoride (PVDF) piezoelectric beam with different load resistances, of which the optimal value could be found on each Reynolds number. The highest power output was found to be 3.19 µW, at 9.8 m/s of flow speed (Re = 20077) and 27 MΩ of load resistance.

This paper investigates the dependency of wave energy conversion on the spectral bandwidth of sea-states. To this aim, the performance of an axisymmetrical Wave Energy Converter is assessed in the frequency domain by using a stochastic model in two far different wave climates (Portugal and North Sea) both represented by more than 23000 energy spectral densities obtained from measurements. The correlation between the performance and various bandwidth parameters found in the literature is observed. Then, refined methods for predicting the long-term converted wave energy based on wave statistics including spectral bandwidth are compared to more common procedures and conclusions are drawn.

The paper presents basic information about photovoltaic cell operating principles and applied technologies. Statistical data that describes trends in photovoltaic generation development is reviewed. Information is analyzed that describes the sales of photovoltaic cells, increase in the installed capacity and development of the technology and prices. The paper comprehensively addresses the legal context of the development photovoltaics in Poland, starting from government plans for relevant programmes, and ending with an assessment of the most important regulations in EU and national law.

In this research paper, the performance of an air-cored axial flux permanent magnet synchronous generator is evaluated for low speed, direct drive applications using 3D finite element modeling and experimental tests. The structure of the considered machine consists of double rotor and coreless stator, which results in the absence of core losses, reduction of stator weight and elimination of cogging torque. In addition, the generator output voltage is sinusoidal in low speed operation and has a linear relationship with rotor speed, which makes it a suitable option for wind turbine applications. The simulation results of the proposed generator coincide very well with the experimental results on a system realized in the laboratory.