OALib Journal期刊

ISSN: 2333-9721



匹配条件: “ Windmills” ,找到相关结果约8条。
Using of High Altitude Wind Energy  [PDF]
Alexander Bolonkin
Smart Grid and Renewable Energy (SGRE) , 2011, DOI: 10.4236/sgre.2011.22010
Abstract: Ground based, wind energy extraction systems have reached their maximum capability. The limitations of current de-signs are: wind instability, high cost of installations, and small power output of a single unit. The wind energy industry needs of revolutionary ideas to increase the capabilities of wind installations. This article suggests a revolutionary innovation which produces a dramatic increase in power per unit and is independent of prevailing weather and at a lower cost per unit of energy extracted. The main innovation consists of large free-flying air rotors positioned at high altitude for power and air stream stability, and an energy cable transmission system between the air rotor and a ground based electric generator. The air rotor system flies at high altitude up to 14 km. A stability and control is provided and systems enable the changing of altitude. This article includes six examples having a high unit power output (up to 100 MW). The proposed examples provide the following main advantages: 1) Large power production capacity per unit—up to 5,000 - 10,000 times more than conventional ground-based rotor designs; 2) The rotor operates at high altitude of 1 - 14 km, where the wind flow is strong and steady; 3) Installation cost per unit energy is low; 4) The installation is environmentally friendly (no propeller noise).
Nonderogatory directed windmills
Revista Colombiana de Matemáticas , 2008,
Abstract: a directed graph g is nonderogatory if its adjacency matrix a is nonderogatory, i.e., the characteristic polynomial of a is equal to the minimal polynomial of a. given integers r≥ 2 and h≥ 3, a directed windmill mh(r) is a directed graph obtained by coalescing r dicycles of length h in one vertex. in this article we solve a conjecture proposed by gan and koo ([3]): mh(r) is nonderogatory if and only if r=2.
Nicolaos Antonio CUTULULIS
Annals of Dunarea de Jos , 2004,
Abstract: This paper focuses on the development of a feedback linearization control for a variable speed fixed pitch wind turbine driving a permanent magnet synchronous generator. The power system is considered to operate on an insular grid. The feedback linearization controller aims to maximize the energy captured from the wind, for varying wind speeds. Numerical simulation results are presented to demonstrate the effectiveness of the feedback linearization controller.
Real Time Wind Turbine Simulator Based On Frequency Controlled AC Servomotor
Nicolaos Antonio CUTULULIS,Mihai CIOBOTARU,Emil CEANG?,Mina Emil ROSU
Annals of Dunarea de Jos , 2002,
Abstract: This paper is a contribution to the development of a real time wind turbine simulator. The simulator is designed to generate wind power on its shaft, and provide the static and dynamic characteristics of a given turbine. The general structure of the simulator is composed of two subsystems: a “soft simulator” which realizes the real time simulation of the wind turbine, on the basis of the mathematical model, an electromechanical tracking system which receives the reference signal from the softsimulator, and provides a measurable output variable transmitted as response variable to the soft-simulator. The work concerns a wind turbine simulator using a tracking system realized on the basis on a frequency controlled AC servo-motor. This servo-motor is mechanically coupled with a pendulum machine, which realises the shaft torque of the electrical generator. The experimental system is built around the DS1103 PPC Controlled Board (dSPACE), which offers a rapid control prototyping, by Matlab-Simulink software tools. Experimental results from the real time WTS are presented.
Performance of heavy ductile iron castings for windmills
Iulian Riposan,Mihai Chisamera,Stelian Stan
China Foundry , 2010,
Abstract: The main objective of the present paper is to review the specific characteristics and performance obtaining conditions of heavy ductile iron (DI) castings, typically applied in windmills industry, such as hubs and rotor housings. The requirements for high impact properties in DI at low temperatures are part of the EN-GJS-400-18U-LT (SRN 1563) commonly referred to as GGG 40.3 (DIN 1693). Pearlitic influence factor (Px) and antinodularising action factor (K1) were found to have an important influence on the structure and mechanical properties, as did Mn and P content, rare earth (RE) addition and inoculation power. The presence of high purity pig iron in the charge is extremely beneficial, not only to control the complex factors Px and K1, but also to improve the ‘metallurgical quality’ of the iron melt. A correlation of C and Si limits with section modulus is very important to limit graphite nodule flotation. Chunky and surface-degenerated graphite are the most controlled graphite morphologies in windmills castings. The paper concluded on the optimum iron chemistry and melting procedure, Mg-alloys and inoculants peculiar systems, as well as on the practical solutions to limit graphite degeneration and to ensure castings of the highest integrity, typically for this field.
Wind Turbine Incident/Complaint Reports in Ontario, Canada: A Review—Why Are They Important?  [PDF]
Carmen M. Krogh, E. Jane Wilson, Mary E. Harrington
Open Access Library Journal (OALib Journal) , 2019, DOI: 10.4236/oalib.1105200
Background: The introduction of industrial wind turbines into quiet rural en-vironments in Ontario, Canada has resulted in complaints about environmental noise and adverse health effects. Ontario has a process whereby residents can report noise to government. Official government records of Incident Reports/Complaints submitted by residents living near operating wind turbine installations were obtained through a Freedom of Information request. This article presents an evaluation of this process while commenting on the significance of Incident Reports/Complaints. Methods: Government records of Incident Reports/Complaints were analysed. Peer reviewed publications, conference presentations, judicial proceedings, government resources, and other sources were evaluated and considered in context with the topic under discussion. Objectives: The purpose of this article is to present the role and significance of Incident Reports/Complaints and discuss the value of these when assessing outcomes related to the introduction of wind turbines into a quiet rural environment. Results: Government records document 4574 Incident Reports/Complaints received by Ontario’s hotline (2006- 2016). There was no ministry response to over 50% of more than 3000 submitted formal complaints (2006-2014). Another 30% were noted as “deferred” response. Only 1% of the reports received a priority response. Provincial Officers noted in summary reports that people were reporting health effects such as: headache, sleep deprivation, annoyance, and ringing or pressure sensation in the head and ears. Health effects were reported many times including those occurring among children. Discussion: In the case of wind power installations, Incident Reports/Complaints are an important source of information for evaluating outcomes of introducing a new noise source into a quiet rural environment and are a form of public health surveillance. These reports can highlight risks to a healthy community living environment, act as an early warning system, and aid in evaluation of government policy initiatives. They may also be used before legal tribunals in public or private actions.
Herbivore dung deposit counts around drinking troughs in the Kruger National Park
I. Thrash,G.K. Theron,J. du P. Bothma
Koedoe : African Protected Area Conservation and Science , 1993, DOI: 10.4102/koedoe.v36i1.365
Abstract: The density of deposits of dung of indigenous large herbivores was measured in transects starting at drinking troughs in the Kruger National Park. The aim was to test whether a relationship exists between intensity of (large indigenous) herbivore use and distance from drinking troughs. There was a significant positive relationship between intensity of herbivore use and'distance from the troughs. The variance was too high, however, to detect relationships at individual transects or to warrant further modelling of the relationship. It was concluded that there was indeed a slight concentration of large herbivore rangeland use around the troughs.
Nonderogatory directed windmills Molinos de viento dirigidos no derogatorios
Revista Colombiana de Matemáticas , 2008,
Abstract: A directed graph G is nonderogatory if its adjacency matrix A is nonderogatory, i.e., the characteristic polynomial of A is equal to the minimal polynomial of A. Given integers r≥ 2 and h≥ 3, a directed windmill Mh(r) is a directed graph obtained by coalescing r dicycles of length h in one vertex. In this article we solve a conjecture proposed by Gan and Koo ([3]): Mh(r) is nonderogatory if and only if r=2. Un grafo dirigido G es no-derogatorio si su matriz de adyacencia A es no-derogatoria, es decir el polinomio característico de A es igual al polinomio minimal de A. Dados enteros r≥ 2 y h≥ 3, el molino de viento dirigido Mh(r) es un grafo dirigido que se obtiene por medio de la coalescencia de r diciclos de longitud h en un vértice. En este artículo resolvemos una conjetura propuesta por Gan y Koo ([3]): Mh(r) es no-derogatorio si, y sólo si, r=2.

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