Academic literature on the topic 'Ricci-plates'

Turbin angin adalah salah satu alternatif untuk mengurangi beban listrik di wilayah perkotaan. Di wilayah perkotaan terdapat gedung bertingkat dengan jumlah yang cukup banyak. Sehingga menjadi lokasi yang tepat untuk aplikasi turbin angin sekaligus mengurangi beban listrik. Tipe turbin yang tepat untuk aplikasi gedung bertingkat adalah turbin angin sumbu vertikal (VAWT). Salah satu jenis VAWT adalah turbin Savonius. Turbin angin Savonius konvensional memiliki kinerja yang rendah seperti koefisien daya dan torsi yang rendah dibandingkan dengan turbin angin jenis lain. Ini terjadi karena aliran angin dapat menyebabkan tekanan negatif pada salah satu sisi sudu. Untuk mengatasi masalah ini, turbin angin Savonius konvensional dikombinasikan dengan guide vane. Tujuan dari penelitian ini adalah untuk mempelajari pengaruh guide vane terhadap performa dan karakteristik pola aliran sekitar turbin angin Savonius. Model numerik dihitung menggunakan persamaan Navier-Stokes dengan model turbulen k-ε standar. Analisa menggunakan software ANSYS-Fluent R15. Simulasi dilakukan pada arah angin yang berbeda, antara lain: 0o, 30o, 60o pada kecepatan angin 2 m/s. Hasil penelitian menunjukkan bahwa guide vane mampu menambah laju aliran udara yang menuju sudu turbin dan meningkatkan performa turbin angin Savonius sebesar 22,2%. Kata kunci: CFD, guide vane, performa, pola aliran, turbin angin SavoniusDaftar RujukanAkwa, J. V., Alves, G., & Petry, A. P. (2012). Discussion on the veri fi cation of the overlap ratio in fl uence on performance coef fi cients of a Savonius wind rotor using computational fl uid dynamics. 38, 141–149. https://doi.org/10.1016/j.renene.2011.07.013Akwa, J. V., Vielmo, H. A., & Petry, A. P. (2012). A review on the performance of Savonius wind turbines. Renewable and Sustainable Energy Reviews, 16(5), 3054–3064. https://doi.org/10.1016/j.rser.2012.02.056Alessandro, V. D., Montelpare, S., Ricci, R., & Secchiaroli, A. (2010). Unsteady Aerodynamics of a Savonius wind rotor : a new computational approach for the simulation of energy performance. Energy, 35(8), 3349–3363. https://doi.org/10.1016/j.energy.2010.04.021Chong, W. T., Fazlizan, A., Poh, S. C., Pan, K. C., Hew, W. P., & Hsiao, F. B. (2013). The design , simulation and testing of an urban vertical axis wind turbine with the omni-direction-guide-vane q. APPLIED ENERGY, 5–8. https://doi.org/10.1016/j.apenergy.2012.12.064Chong, W. T., Poh, S. C., Abdullah, N., Naghavi, M. S., & Pan, K. C. (2010). Vertical Axis Wind Turbine with Power-Augmentation-Guide-Vane for Urban High Rise Application 3 . Building integrated wind-solar hybrid energy generation system and rain water collector. (September), 1–6.Damak, a., Driss, Z., & Abid, M. S. (2013). Experimental investigation of helical Savonius rotor with a twist of 180?? Renewable Energy, 52, 136–142. https://doi.org/10.1016/j.renene.2012.10.043Hasan, M. H., Muzammil, W. K., Mahlia, T. M. I., Jannifar, A., & Hasanuddin, I. (2012). A review on the pattern of electricity generation and emission in Indonesia from 1987 to 2009. Renewable and Sustainable Energy Reviews, 16(5), 3206–3219. https://doi.org/10.1016/j.rser.2012.01.075Mohamed, M. H., Janiga, G., Pap, E., & Thévenin, D. (2010). Optimization of Savonius turbines using an obstacle shielding the returning blade. Renewable Energy, 35(11), 2618–2626. https://doi.org/10.1016/j.renene.2010.04.007Nobile, R., Vahdati, M., & Barlow, J. F. (2013). Unsteady flow simulation of a vertical axis wind turbine : a two-dimensional study. (July), 1–10.Pope, K., Rodrigues, V., Doyle, R., Tsopelas, a., Gravelsins, R., Naterer, G. F., & Tsang, E. (2010). Effects of stator vanes on power coefficients of a zephyr vertical axis wind turbine. Renewable Energy, 35(5), 1043–1051. https://doi.org/10.1016/j.renene.2009.10.012Ricci, R., Romagnoli, R., Montelpare, S., & Vitali, D. (2016). Experimental study on a Savonius wind rotor for street lighting systems q. Applied Energy, 161, 143–152. https://doi.org/10.1016/j.apenergy.2015.10.012Roy, S., & Saha, U. K. (2015). Wind tunnel experiments of a newly developed two-bladed Savonius-style wind turbine. Applied Energy, 137, 117–125. https://doi.org/10.1016/j.apenergy.2014.10.022Soo, K., Ik, J., Pan, J., & Ryu, K. (2015). Effects of end plates with various shapes and sizes on helical Savonius wind turbines. Renewable Energy, 79, 167–176. https://doi.org/10.1016/j.renene.2014.11.035Tartuferi, M., D’Alessandro, V., Montelpare, S., & Ricci, R. (2015). Enhancement of Savonius wind rotor aerodynamic performance: a computational study of new blade shapes and curtain systems. Energy, 79, 371–384. https://doi.org/10.1016/j.energy.2014.11.023Walker, S. L. (2011). Building mounted wind turbines and their suitability for the urban scale — A review of methods of estimating urban wind resource. Energy & Buildings, 43(8), 1852–1862. https://doi.org/10.1016/j.enbuild.2011.03.032

En termes généraux, une métrique ALF de dimension réelle 2n devrait être une métrique complète telle que son cône asymptotique soit de dimension 2n−1, la croissance de volume de cette métrique soit de l'ordre de 2n−1, et sa courbure sectionnelle tende vers 0 à l'infini. Plus précisément, dans cette thèse, une métrique ALF de dimension réelle 2n a un cône métrique de dimension 2n−1 comme cône asymptotique,elle a une croissance de volume de l'ordre de 2n − 1 et sa courbure sectionnelle est bornée par C/ρ où ρ est la distance à partir d'un point mesurée par la métrique riemannienne. Étant donné que les métriques ALF Calabi-Yau de dimension 4 ont été bien étudiées, l'objectif de la thèse est de trouver des exemples de métriques ALF Calabi-Yau dedimensions supérieures, ici par dimensions supérieures nous entendons que la dimension réelle de l'espace est supérieure à 4.Dans la thèse, je montrerai d'abord que la déformation de Taub-NUT d'un cône hyperkählerien par rapport à une S^1-symétrie localement libre est hyperkählerienne ALF. Modélisée sur cette métrique à l'infini, je montrerai l'existence de métriques ALF Calabi-Yau sur certaines résolutions crepantes. En particulier, je montrerai qu'il existe des métriques ALF Calabi-Yau sur les fibrés canoniques des variétés de contact de Fano homogènes classiques. Ensuite, je prouverai qu'une classe spéciale de métrique Calabi-Yau complète sur Cn construite par Apostolov et Cifarelli est ALF avec cône asymptotique (C^n−1/Z_n−1) × R. Modélisée sur ces métriques à l'infini, je montrerai alors l'existence de métriques ALF Calabi-Yau sur les résolutions crepantes de C^n
Roughly speaking, an ALF metric of real dimension 2n should bea complete metric such that its asymptotic cone is 2n−1 dimensional, the volume growth of this metric is of order 2n − 1 and its sectional curvature tends to 0 at infinity. More precisely, in this thesis, an ALF metric of real dimension 2n has a 2n−1 dimensional metric cone as its asymptotic cone, it has volume growth of order 2n−1 and its sectional curvature is bounded by C/ρ where ρ is the distance from a point of it measured by the Riemannian metric. Since 4 dimensional ALF Calabi-Yau metrics have been well studied, the object of the thesis is to find example of higher dimensional ALF Calabi-Yau metrics, here by higher dimensional we mean the real dimension of the space is greater than 4. In the thesis, I will first show that the Taub-NUT deformation of a hyperkähler cone with respect to a locally free S^1-symmetry is ALF hyperkähler. Modelled on this metric at infinity, I will show the existence of ALF Calabi-Yau metric on certain crepant resolutions. Inparticular, I will show that there exist ALF Calabi-Yau metrics on canonical bundles of classical homogeneous Fano contact manifolds. Then I will prove that a special class of complete Calabi-Yau metric on Cn constructed by Apostolov and Cifarelli is ALF with asymptotic cone (C^n−1/Z_n−1)×R. Modelled on these metrics at infinity, I will then show the existence of ALF Calabi-Yau metric on crepant resolutions of C^n

Cette thèse concerne la géométrie asymptotique de variétés riemanniennes complètes non compactes, dont la courbure tend vers zéro à l'infini, assez vite. Afin de compléter des travaux déjà existants, on s'attache à comprendre le cas où la croissance du volume est non maximale, c'est-à-dire strictement moins rapide que dans l'espace euclidien de même dimension. Dans ce contexte, on prouve tout d'abord une inégalité de Sobolev à poids et une inégalité de Hardy, qui permettent de généraliser nombre de résultats établis quand la croissance du volume est maximale. On obtient en particulier des résultats de rigidité et de finitude de la topologie pour des variétés Ricci plates et asymptotiquement plates. On obtient ensuite un résultat de structure asymptotique pour une classe d'instantons gravitationnels : typiquement, ceux qui ont une croissance du volume cubique sont asymptotes à des fibrations en cercles au-dessus d'une variété asymptotiquement localement euclidienne .

Abstract THE second romance has come down to us in a Theban manuscript, which dates from the first half of the first century A.D. The fragments of it were bought from a dealer at Gizeh in 1904 by Borchardt and Rubensohn, and in 1905 by Seymour de Ricci. The larger part, which was acquired by Borchardt and Rubensohn, has gone to the University of Strasburg, where Spiegelberg discovered the subject of it. It has been published, as well as the pieces recovered by Ricci in W. Spiegelberg, Der Sagenkreis des Konigs Petubastis, nach dem Strassburger Demotischen Papyrus sowie den Wiener und Pariser Bruckstucken, 4to, Leipzig, 1910, So and 102 pages, and 22 plates in phototype. So far as it is possible to judge at present, it contains the Theban version of the theme dealt with in the first romance. The cuirass is replaced by the throne of Amon, probably, as I have said in the Introduction (p. cxxiii), by the sacred throne on which the priests placed the strangely shaped emblem, representing one of the types of the god of the Gr.-eco-Roman period. The personages that surround Pharaoh in the narrative are many of them the same as those of the previous story-Pakrur prince of the East, Pemu son of Eienharerou-Inaros prince of Heliopolis, Ankhhoru son of Pharaoh and his son Tak.hos, and Minnebmei prince of Elephantine; and yet, as Spiegelberg has justly observed (Der Sagenkreis, p. 8), years have passed since the affair of the cuirass, and new personages have arisen-Pesnufi, the son of Pakrur, and a young prophet of Horus of Buto who is not named anywhere, but whose auxiliaries are named generally as the Ameu. This name, which Spiegelberg translates literally as the Shepherds, and interprets as the Asiatics, affords the basis for a very ingenious comparison with the legend of Osarsuph, the priest of Heliopolis, the Moses of Jewish tradition, and his companions the shepherds or the Impure of Asia;