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1

Probabilistic analysis of mean-response along-wind induced vibrations on wind turbine towers using wireless network data sensors  

Microsoft Academic Search

Wind turbine systems are attracting considerable attention due to concerns regarding global energy consumption as well as sustainability. Advances in wind turbine technology promote the tendency to improve efficiency in the structure that support and produce this renewable power source, tending toward more slender and larger towers, larger gear boxes, and larger, lighter blades. The structural design optimization process must

Antonio Velazquez; Raymond A. Swartz

2011-01-01

2

Towers for Offshore Wind Turbines  

NASA Astrophysics Data System (ADS)

Increasing energy demand coupled with pollution free production of energy has found a viable solution in wind energy. Land based windmills have been utilized for power generation for more than two thousand years. In modern times wind generated power has become popular in many countries. Offshore wind turbines are being used in a number of countries to tap the energy from wind over the oceans and convert to electric energy. The advantages of offshore wind turbines as compared to land are that offshore winds flow at higher speed than onshore winds and the more available space. In some land based settings, for better efficiency, turbines are separated as much as 10 rotor diameters from each other. In offshore applications where only two wind directions are likely to predominate, the distances between the turbines arranged in a line can be shortened to as little as two or four rotor diameters. Today, more than a dozen offshore European wind facilities with turbine ratings of 450 kw to 3.6 MW exist offshore in very shallow waters of 5 to 12 m. Compared to onshore wind turbines, offshore wind turbines are bigger and the tower height in offshore are in the range of 60 to 80 m. The water depths in oceans where offshore turbines can be located are within 30 m. However as the distance from land increases, the costs of building and maintaining the turbines and transmitting the power back to shore also increase sharply. The objective of this paper is to review the parameters of design for the maximum efficiency of offshore wind turbines and to develop types offshore towers to support the wind turbines. The methodology of design of offshore towers to support the wind turbine would be given and the environmental loads for the design of the towers would be calculated for specific cases. The marine corrosion on the towers and the methods to control the corrosion also would be briefly presented. As the wind speeds tend to increase with distance from the shore, turbines build father offshore will be able to capture more wind energy. Currently two types of towers are considered. Cylindrical tubular structures and truss type structures. But truss type structures have less weight and flexibility in design. The construction of the offshore towers to harness the wind energy is also presented. The results will include the calculation of wind and wave forces on the tower and the design details for the tower.

Kurian, V. J.; Narayanan, S. P.; Ganapathy, C.

2010-06-01

3

Modal analysis of wind turbine tower  

Microsoft Academic Search

As the support structure of wind turbine, the tower bears alternating loads of wind when the wind turbine runs. To ensure the reliability of the wind turbine, it's necessary to carry out modal analysis on the tower, and this would prevent the natural frequency of the tower close to the rated speed of wind turbine. In this paper, finite element

Jie Chen; Dongxiang Jiang

2010-01-01

4

Probabilistic analysis of mean-response along-wind induced vibrations on wind turbine towers using wireless network data sensors  

NASA Astrophysics Data System (ADS)

Wind turbine systems are attracting considerable attention due to concerns regarding global energy consumption as well as sustainability. Advances in wind turbine technology promote the tendency to improve efficiency in the structure that support and produce this renewable power source, tending toward more slender and larger towers, larger gear boxes, and larger, lighter blades. The structural design optimization process must account for uncertainties and nonlinear effects (such as wind-induced vibrations, unmeasured disturbances, and material and geometric variabilities). In this study, a probabilistic monitoring approach is developed that measures the response of the turbine tower to stochastic loading, estimates peak demand, and structural resistance (in terms of serviceability). The proposed monitoring system can provide a real-time estimate of the probability of exceedance of design serviceability conditions based on data collected in-situ. Special attention is paid to wind and aerodynamic characteristics that are intrinsically present (although sometimes neglected in health monitoring analysis) and derived from observations or experiments. In particular, little attention has been devoted to buffeting, usually non-catastrophic but directly impacting the serviceability of the operating wind turbine. As a result, modal-based analysis methods for the study and derivation of flutter instability, and buffeting response, have been successfully applied to the assessment of the susceptibility of high-rise slender structures, including wind turbine towers. A detailed finite element model has been developed to generate data (calibrated to published experimental and analytical results). Risk assessment is performed for the effects of along wind forces in a framework of quantitative risk analysis. Both structural resistance and wind load demands were considered probabilistic with the latter assessed by dynamic analyses.

Velazquez, Antonio; Swartz, Raymond A.

2011-03-01

5

Composite wind tower systems and methods of manufacture  

US Patent & Trademark Office Database

The present invention relates generally to composite fiber-reinforced polymer (FRP) wind tower systems and methods of manufacture. More particularly, the present invention relates to a composite FRP wind tower system including a plurality of tower cells for functional engagement with adjacent tower cells along mating surfaces to form a tower section, each tower cell including a lower end and an upper end for telescopic engagement with a tower cell of an adjacent tower section.

2011-01-11

6

Development of wind turbine towers using fiber reinforced polymers  

Microsoft Academic Search

With an ongoing trend in the wind turbine market, the size of wind turbines has been increasing continuously. Larger wind turbines imply an increase in size, weight, and loads acting on the wind turbine tower. This requires towers to be stronger and stiffer, and consequently leads to bigger tower diameters. Because of their size and weight, transportation and erection require

Nibong Ungkurapinan

2005-01-01

7

Differences of Tower and Pibal Wind Profiles.  

National Technical Information Service (NTIS)

The time and space variability of the wind as derived from tower-mounted anemometers and triple-theodolite pilot-balloon (pibal) observations at the same altitude at Green River, Utah, during four nighttime operations in September 1965 is analyzed. Simult...

L. J. Rider M. Armendariz

1966-01-01

8

Wind turbine tower for storing hydrogen and energy  

DOEpatents

A wind turbine tower assembly for storing compressed gas such as hydrogen. The tower assembly includes a wind turbine having a rotor, a generator driven by the rotor, and a nacelle housing the generator. The tower assembly includes a foundation and a tubular tower with one end mounted to the foundation and another end attached to the nacelle. The tower includes an in-tower storage configured for storing a pressurized gas and defined at least in part by inner surfaces of the tower wall. In one embodiment, the tower wall is steel and has a circular cross section. The in-tower storage may be defined by first and second end caps welded to the inner surface of the tower wall or by an end cap near the top of the tower and by a sealing element attached to the tower wall adjacent the foundation, with the sealing element abutting the foundation.

Fingersh, Lee Jay (Westminster, CO) [Westminster, CO

2008-12-30

9

Structural Design of Shanghai Tower for Wind Loads  

Microsoft Academic Search

Nearby Jin Mao tower and the World Financial Center, the 632-meter, 121-story mixed-use Shanghai tower will be the tallest super tall tower in the new Lujiazui Finance and Trade Zone of Shanghai. Due to the super tall height, curved façade and spiraling form of the Shanghai tower project, wind is the dominant lateral load and governed many aspects of the

X. Zhaoa; J. M. Ding; H. H. Suna

2011-01-01

10

Summary of tower designs for large horizontal axis wind turbines  

NASA Technical Reports Server (NTRS)

Towers for large horizontal axis wind turbines, machines with a rotor axis height above 30 meters and rated at more than 500 kW, have varied in configuration, materials of construction, type of construction, height, and stiffness. For example, the U.S. large HAWTs have utilized steel truss type towers and free-standing steel cylindrical towers. In Europe, the trend has been to use only free-standing and guyed cylindrical towers, but both steel and reinforced concrete have been used as materials of construction. These variations in materials of construction and type of construction reflect different engineering approaches to the design of cost effective towers for large HAWTs. Tower designs are the NASA/DOE Mod-5B presently being fabricated. Design goals and requirements that influence tower configuration, height and materials are discussed. In particular, experiences with United States large wind turbine towers are elucidated. Finally, current trends in tower designs for large HAWTs are highlighted.

Frederick, G. R.; Savino, J. M.

1986-01-01

11

Low-cost Triangular Lattice Towers for Small Wind Turbines  

NASA Astrophysics Data System (ADS)

This thesis focuses on the study of low-cost steel and bamboo triangular lattice towers for small wind turbines. The core objective is to determine the material properties of bamboo and assess the feasibility of bamboo towers. Using the experimentally determined buckling resistance, elastic modulus, and Poisson's ratio, a 12 m high triangular lattice tower for a 500W wind turbine has been modeled as a tripod to formulate the analytical solutions for the stresses and tower deflections, which enables design of the tower based on buckling strength of tower legs. The tripod formulation combines the imposed loads, the base distance between the legs and tower height, and cross-sectional dimensions of the tower legs. The tripod model was used as a reference for the initial design of the bamboo tower and extended to finite element analysis. A 12 m high steel lattice tower was also designed for the same turbine to serve as a comparison to the bamboo tower. The primary result of this work indicates that bamboo is a valid structural material. The commercial software package ANSYS APDL was used to carry out the tower analysis, evaluate the validity of the tripod model, and extend the analysis for the tower design. For this purpose, a 12 m high steel lattice tower for a 500 W wind turbine was examined. Comparison of finite element analysis and analytical solution has shown that tripod model can be accurately used in the design of lattice towers. The tower designs were based on the loads and safety requirements of international standard for small wind turbine safety, IEC 61400-2. For connecting the bamboo sections in the lattice tower, a steel-bamboo adhesive joint combined with conventional lashing has been proposed. Also, considering the low durability of bamboo, periodic replacement of tower members has been proposed. The result of this study has established that bamboo could be used to construct cost-effective and lightweight lattice towers for wind turbines of 500 Watt capacity or smaller. This study concludes that further work on joining of bamboo sections and weathering is required to fully utilize bamboo in practice. In comparison to steel towers, bamboo towers are economically feasible and easy to build. The tower is extremely lightweight, which justifies its application in remote areas, where the transportation is difficult.

Adhikari, Ram Chandra

12

Wind Tunnel Measurements of the Tower Shadow on Models of the ERDA/NASA 100 KW Wind Turbine Tower.  

National Technical Information Service (NTIS)

Detailed wind speed profile measurements were made in the wake of a exp 1 / sub 25 scale and a exp 1 / sub 48 scale tower models to determine the magnitude of the speed reduction (the tower shadow). The exp 1 / sub 25 scale tower modeled closely the actua...

J. M. Savino L. H. Wagner

1976-01-01

13

Remote monitoring and nondestructive evaluation of wind turbine towers  

NASA Astrophysics Data System (ADS)

Wind turbine towers are in need of condition monitoring so as to lower the cost of unexpected maintenance. Wind loading from turbulence and gusts can cause damage in horizontal axis wind turbines even the supporting towers. Monitoring of wind turbines in service using embedded data sensor arrays usually is not targeted at the turbine-tower interaction from the perspective of structural dynamics. In this study the remote monitoring of the tower supporting a horizontal-axis wind turbine was attempted using a microwave interferometer. The dominant frequency of one tower was found to be decreased by more than 20% in 16 months. Numerical modeling using spectral finite elements is in progress and should provide further information regarding frequency shift due to stiffness variation and added mass. Expected outcome will contribute to remote monitoring procedures and nondestructive evaluation techniques for local wind turbine structures during operation.

Chiang, Chih-Hung; Yu, Chih-Peng; Hsu, Keng-Tsang; Cheng, Chia-Chi; Ke, Ying-Tzu; Shih, Yi-Ru

2014-03-01

14

78 FR 11152 - Utility Scale Wind Towers from the People's Republic of China: Countervailing Duty Order  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-570-982] Utility Scale Wind Towers from the People's Republic of China: Countervailing...issuing a countervailing duty order on utility scale wind towers (``wind towers'') from the People's Republic of...

2013-02-15

15

78 FR 11146 - Utility Scale Wind Towers From the People's Republic of China: Antidumping Duty Order  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-981] Utility Scale Wind Towers From the People's Republic of China: Antidumping...is issuing an antidumping duty order on utility scale wind towers (``wind towers'') from the People's Republic of...

2013-02-15

16

77 FR 75978 - Utility Scale Wind Towers From the People's Republic of China: Final Affirmative Countervailing...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [C-570-982] Utility Scale Wind Towers From the People's Republic of China: Final...provided to producers and exporters of utility scale wind towers (wind towers) from the People's Republic of China...

2012-12-26

17

Wind Shear Characteristics at Central Plains Tall Towers (presentation)  

SciTech Connect

The objectives of this report are: (1) Analyze wind shear characteristics at tall tower sites for diverse areas in the central plains (Texas to North Dakota)--Turbines hub heights are now 70-100 m above ground and Wind measurements at 70-100+ m have been rare. (2) Present conclusions about wind shear characteristics for prime wind energy development regions.

Schwartz, M.; Elliott, D.

2006-06-05

18

Wind tunnel test method to study out-of-service tower crane behaviour in storm winds  

Microsoft Academic Search

An experimental method used to study the behaviour of tower cranes in strong winds exposed to the disturbed shear flow induced by the surrounding built environment is proposed. Wind tunnel tests on a tower crane model are described, the tower crane is considered as a rigid body slender structure equipped with a single degree of freedom part: the crane mobile

D. Voisin; G. Grillaud; C. Solliec; A. Beley-Sayettat; J.-L. Berlaud; A. Miton

2004-01-01

19

Wind Shear Characteristics at Central Plains Tall Towers  

SciTech Connect

The object of this study is to analyze wind shear characteristics at tall tower sites in the Central Plains of the United States. The hub heights of modern turbines used for wind farm projects are now 70 meters (m) to 100 m above ground and some advanced turbines under development for deployment during the second half of this decade are rated at 2-5 megawatts of energy generation with rotor diameters near 100 m and hub heights of 100-120 m. These advanced turbines will take advantage of the higher wind speeds aloft to generate more wind energy. Specific knowledge of important wind shear characteristics near and at turbine hub height is needed to optimize turbine design and wind farm layout. Unfortunately, wind speed shear measurements at heights of 80-120 m were virtually nonexistent a few years ago and are still quite uncommon today. The Central Plains is a prime wind energy development region and knowledge about the wind shear characteristics will reduce uncertainty about the resource and enhance wind farm design. Previous analyses of tall tower data (Schwartz and Elliott, 2005) concentrated on data from specific states. The wind energy community has recognized the need to fill the gap of direct wind speed measurements at levels 70 m and higher above the ground. Programs instituted during the last 5 years at the state level and supported by the U.S. Department of Energy's (DOE) State Energy Program initiative have placed anemometers and vanes at several levels on existing tall (70 m+) communication towers. The Central Plains has a fairly high concentration of tall tower sites. The distribution of tall tower sites varies among the states in the Central Plains, because the tall tower program is new and the available state and federal funding to establish tall towers is variable. Our wind resource assessment group at DOE's National Renewable Energy Laboratory (NREL) has obtained much of these necessary measurement data from both individual state sources and regional organizations. Most of the data are available to the public, though data from one tower in Colorado are proprietary. We have begun to analyze important wind climate parameters, including wind shear from the tall towers. A total of 13 tall towers were used for this study. Eleven of the towers had the highest anemometer level between 100 m and 113 m. Two towers had the highest measurement level between 70 m and 85 m above ground. The distribution of the towers among the states is: two sites in Texas and Oklahoma; six sites in Kansas; and one site each in Colorado, South Dakota, and North Dakota. Figure 1 shows the locations and names of the thirteen towers. The wind resource at these sites can be classified as ranging from good-to-excellent. Eight tall tower sites have Class 3 resource, four sites have Class 4 resource, and one has Class 5 resource at 50 m.

Schwartz, M.; Elliott, D.

2006-01-01

20

Comparison of Second Wind Triton Data with Meteorological Tower Measurements  

SciTech Connect

With the increased interest in remote sensing of wind information in recent years, it is important to determine the reliability and accuracy of new wind measurement technologies if they are to replace or supplement conventional tower-based measurements. In this study, we present the results of an analysis characterizing the measurement performance of a state-of-the-art SOund Detection And Ranging (sodar) device when compared to a high-quality tower measurement program. Second Wind Inc. (Somerville, MA, USA) provided NREL with more than six months of data from a measurement program conducted near an operating wind farm in western Texas.

Scott, G.; Elliott, D.; Schwartz, M.

2010-02-01

21

Development of wind turbine towers using fiber reinforced polymers  

NASA Astrophysics Data System (ADS)

With an ongoing trend in the wind turbine market, the size of wind turbines has been increasing continuously. Larger wind turbines imply an increase in size, weight, and loads acting on the wind turbine tower. This requires towers to be stronger and stiffer, and consequently leads to bigger tower diameters. Because of their size and weight, transportation and erection require heavy equipment that makes the use of such towers prohibitive in remote communities. To tackle this problem, a research program was initiated at the University of Manitoba to develop the technology required for the fabrication of wind turbine towers constructed of fiber reinforced polymers (FRP) for use in remote communities in Canada. The research program was carried out in stages. During the first stage, a feasibility study and an analytical investigation on various shapes of FRP towers were conducted. The concept of a multi-cellular composite tower was examined in great detail and the finite element results showed that such a tower could result in almost 45 percent reduction in weight. In the second stage of this research program, a robotic filament winding machine was designed and constructed in the Composites Laboratory of the University of Manitoba. It was used to fabricate the multi-cell tower specimens for testing. The third stage of the research program involved the experimental investigation, which was carried out in three phases. In the first phase, two single cell specimens were tested to failure under lateral loading. The specimens were 8 ft (2.44 m) long. The second phase involved the testing of two single cells loaded in compression. The third phase of the experimental investigation involved the testing of two eight-cell jointed tower specimens. The specimens were octagonal and tapered, with a diameter of 21.4 in (543 mm) at the base and 17.4 in (441 mm) at the top. They were 16 ft (4.88 m) in height and tested as cantilever under static loading. Local buckling was the dominant failure mode of the specimens tested. One of these towers was subsequently repaired and retested to determine whether repairing would restore the original strength of the tower. The last stage of the research program, various finite element models were developed to analyze the structural behavior of tested specimens. The results from finite element models were validated through comparison with experimental results. The finite element models gave a very good prediction of the structural performance of the FRP towers tested.

Ungkurapinan, Nibong

22

Numerical simulation of wind turbine blade-tower interaction  

NASA Astrophysics Data System (ADS)

Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface (AMI) method were presented. The governing equations were the unsteady Reynolds-averaged Navier-Stokes (RANS) which were solved by the pimpleDyMFoam solver, and the AMI method was employed to handle mesh movements. The National Renewable Energy Laboratory (NREL) phase VI wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds (5, 10, 15, and 25 m/s) at a fixed blade pitch and constant rotational speed. Detailed numerical results of vortex structure, time histories of thrust, and pressure distribution on the blade and tower were presented. The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine, while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower. Also, strong interaction of blade tip vortices with separation from the tower was observed.

Wang, Qiang; Zhou, Hu; Wan, Decheng

2012-09-01

23

Infield testing of a steel wind turbine tower  

Microsoft Academic Search

\\u000a The strong drive to exploit wind energy has recently led to consideration of new types of location for wind turbines, including\\u000a mountain regions. A major concern for wind farm installation in these sites is the long-term reliability of the support structures.\\u000a In a flexible steel tower, a combination of vortex shedding and gusting caused fatigue cracks at the base joint.

Marco Molinari; Matteo Pozzi; Daniele Zonta; Lorenzo Battisti

24

Structural health monitoring of wind towers: residual fatigue life estimation  

NASA Astrophysics Data System (ADS)

In a recent paper (Benedetti et al 2011 Smart Mater. Struct. 20 055009), the authors investigated the possibility of detecting cracks in critical sites of onshore wind towers using a radial arrangement of strain sensors around the tower periphery in the vicinity of the base welded joint. Specifically, the strain difference between adjacent strain sensors is used as a damage indicator. The number of sensors to be installed is determined by the minimum crack size to be detected, which in turn depends on the expected extreme wind conditions and programmed inspection/repair schedule. In this companion paper, we address these issues by investigating possible strategies for residual fatigue life assessment and management of onshore wind towers once the crack has been detected. For this purpose, fracture mechanics tests are carried out using welded samples to quantify the resistance to fatigue crack growth as well as the elastic-plastic fracture toughness of the welded joint at the tower base. These material strength characteristics are used to estimate (i) the critical crack size for structural integrity on the basis of fracture toughness tests, elastoplastic finite element analyses and loading spectra under extreme wind conditions, (ii) the residual life before structural collapse, applying a frequency-domain method to typical in-service wind actions and wind directionality.

Benedetti, M.; Fontanari, V.; Battisti, L.

2013-04-01

25

77 FR 75984 - Utility Scale Wind Towers From the Socialist Republic of Vietnam: Final Determination of Sales at...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-552-814] Utility Scale Wind Towers From the Socialist Republic of Vietnam: Final...determination in the antidumping investigation of utility scale wind towers (``wind towers'') from the Socialist Republic of...

2012-12-26

26

77 FR 75992 - Utility Scale Wind Towers From the People's Republic of China: Final Determination of Sales at...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-570-981] Utility Scale Wind Towers From the People's Republic of China: Final...determination in the antidumping investigation of utility scale wind towers (``wind towers'') from the People's Republic of...

2012-12-26

27

78 FR 11150 - Utility Scale Wind Towers From the Socialist Republic of Vietnam: Amended Final Determination of...  

Federal Register 2010, 2011, 2012, 2013

...Trade Administration [A-552-814] Utility Scale Wind Towers From the Socialist Republic of Vietnam: Amended...is issuing an antidumping duty order on utility scale wind towers (``wind towers'') from the Socialist Republic of...

2013-02-15

28

Comparison of Second Wind Triton Data with Meteorological Tower Measurements  

Microsoft Academic Search

With the increased interest in remote sensing of wind information in recent years, it is important to determine the reliability and accuracy of new wind measurement technologies if they are to replace or supplement conventional tower-based measurements. In this study, we present the results of an analysis characterizing the measurement performance of a state-of-the-art SOund Detection And Ranging (sodar) device

G. Scott; D. Elliott; M. Schwartz

2010-01-01

29

Simulation Model of Wind Turbine 3p Torque Oscillations due to Wind Shear and Tower Shadow  

Microsoft Academic Search

To determine control structures and possible power quality issues, the dynamic torque generated by the blades of a wind turbine must be represented. This paper presents an analytical formulation of the generated aerodynamic torque of a three bladed wind turbine including effects of wind shear and tower shadow. The comprehensive model includes turbine specific parameters such as radius, height, and

Dale S. L. Dolan; P. W. Lehn

2006-01-01

30

Performance prediction of a multi-stage wind tower for indoor cooling  

NASA Astrophysics Data System (ADS)

A theoretical model is developed to establish an in-depth understanding of the performance of a three-stage wind tower with a bypass system for indoor cooling in rural dry and hot climates. Model simulations are presented for a wide range of ambient conditions that include inlet wind speed, inlet temperature and relative humidity. Simulation results provide an insight into the desirable water flow rates and air-to-water loadings for comfort zone temperatures and relative humidity levels at the exit of the wind tower. Simulations show wind towers with variable cross-sections provide an increase in the cooling power for the same inlet wind speed, inlet air temperature and relative humidity when compared to wind towers with a constant cross-section. The study shall lead to a better understanding to designing wind towers that are both environmentally friendly and energy efficient.

Issa, Roy J.; Chang, Byungik

2012-08-01

31

Vibration analysis of three guyed-tower designs for intermediate-size wind turbines  

SciTech Connect

A method for analyzing the vibrations of horizontal axis wind turbines was used to analyze three guyed tower designs for intermediate size wind turbines. The method, which uses a simple wind turbine structural model, was used to estimate the four lowest natural frequencies of vibration of the three towers concepts. A parametric study was performed on each tower to determine the effect of varying various tower properties such as the inertia and stiffness properties of the tower and guys, the inertia values of the nacelle and rotor, and the rotational speed of the rotor. The results showed that only the two lowest frequencies were in a range where they could be excited by the rotor blade passing frequencies. The analysis also showed that these two frequencies could be tuned by varying the guy stiffnesses, the guy attachment point on the tower, the tower mass and stiffness, and the nacelle/rotor/power train masses.

Christie, R.J.

1982-03-01

32

Wind turbine generator application places unique demands on tower design and materials  

Microsoft Academic Search

The most relevant contractual tower design requirements and goal for the Mod-1 tower are related to steel truss tower construction, cost-effective state-of-the-art design, a design life of 30 years, and maximum wind conditions of 120 mph at 30 feet elevation. The Mod-1 tower design approach was an iterative process. Static design loads were calculated and member sizes and overall geometry

J. P. Kita

1978-01-01

33

Recent Results From the NOAA\\/ESRL GMD Tall Tower Network  

Microsoft Academic Search

We will present a summary of new results from NOAA Earth System Research Laboratory`s Tall Tower greenhouse gas monitoring network. The tower network is operated by the Global Monitoring Division, which also maintains the global Cooperative Air Sampling network and a network of aircraft profiling sites over North America. Tall tower CO2 mixing ratio measurements are sensitive to upwind fluxes

A. E. Andrews; P. P. Tans; W. Peters; A. Hirsch; C. Sweeney; G. Petron; J. Kofler; C. Zhao; K. Masarie; S. C. Wofsy; D. M. Matross; P. Mahadevan; M. Longo; C. Gerbig; J. C. Lin

2006-01-01

34

In-service testing of wind turbine towers using a microwave sensor  

Microsoft Academic Search

A remote-sensing technique based on microwave interferometry is applied to dynamic testing of wind turbine towers for power generation. A high-speed interferometric radar is able to sample the structure at a rate high enough for modal and transient analysis. An experimental campaign is reported carried out on wind turbine towers of a power plant in north Sardinia, Italy.

Massimiliano Pieraccini; Filippo Parrini; Matteo Fratini; Carlo Atzeni; Paolo Spinelli

2008-01-01

35

77 FR 37653 - Utility Scale Wind Towers From the People's Republic of China: Alignment of Final Countervailing...  

Federal Register 2010, 2011, 2012, 2013

...Scale Wind Towers From the People's Republic of China: Alignment of Final Countervailing Duty Determination With Final Antidumping...the Wind Tower Trade Coalition,\\3\\ timely requested alignment of the deadline for the final CVD determination with the...

2012-06-22

36

77 FR 50715 - Utility Scale Wind Towers From China and Vietnam; Scheduling of the Final Phase of Countervailing...  

Federal Register 2010, 2011, 2012, 2013

...731-TA-1195-1196 (Final)] Utility Scale Wind Towers From China and Vietnam; Scheduling...from China and Vietnam of utility scale wind towers, provided for in subheading 7308...defined the subject merchandise as certain wind towers, whether or not tapered, and...

2012-08-22

37

Research on the Wind-induced Vibration Coefficient of Transmission Tower-line System  

NASA Astrophysics Data System (ADS)

The six different non-linear finite element model of the transmission tower-line system which have different spans and different height difference was established by the finite element analysis software, and wind velocity time series with resorting to weighted amplitude wave superposition (WAWS) was simulated. Based on the established models and the simulated wind velocity time series, the wind-induced response of transmission tower-line system in time history was calculated to achieve wind-induced vibration coefficient of transmission towers of various models. By comparative analyzing, span and height difference on the impact of wind-induced vibration coefficient of transmission towers was studied. The results show that the span and height difference have a certain impact on wind-induced vibration coefficient of transmission towers, and the effects on tower top are more obvious than tower bottom. With the increase of span, wind-induced vibration coefficient reduces gradually, but with the increase of height difference, wind-induced vibration coefficient increases gradually.

Chunming, Wei; Bin, Ma; Tingting, Su

38

The impact of tower shadow, yaw error, and wind shears on power quality in a wind-diesel system  

Microsoft Academic Search

To study the impact of aerodynamic aspects of a wind turbine (i.e. tower shadow, wind shears, yaw error, and turbulence) on the power quality of a wind-diesel system, all electrical, mechanical and aerodynamic aspects of the wind turbine must be studied. Moreover, the contribution of the diesel generator system and its controllers should be considered. This paper, describes how the

R. F. Bahramjerdi; G. Moschopoulos; M. Moallem

2009-01-01

39

Wind turbine generator application places unique demands on tower design and materials  

NASA Technical Reports Server (NTRS)

The most relevant contractual tower design requirements and goal for the Mod-1 tower are related to steel truss tower construction, cost-effective state-of-the-art design, a design life of 30 years, and maximum wind conditions of 120 mph at 30 feet elevation. The Mod-1 tower design approach was an iterative process. Static design loads were calculated and member sizes and overall geometry chosen with the use of finite element computer techniques. Initial tower dynamic characteristics were then combined with the dynamic properties of the other wind turbine components, and a series of complex dynamic computer programs were run to establish a dynamic load set and then a second tower design.

Kita, J. P.

1978-01-01

40

Vibration analysis of three guyed tower designs for intermediate size wind turbines  

NASA Astrophysics Data System (ADS)

Three guyed tower designs were analyzed for intermediate size wind turbines. The four lowest natural frequencies of vibration of the three towers concepts were estimated. A parametric study was performed on each tower to determine the effect of varying such tower properties as the inertia and stiffness of the tower and guys, the inertia values of the nacelle and rotor, and the rotational speed of the rotor. Only the two lowest frequencies were in a range where they could be excited by the rotor blade passing frequencies. There two frequencies could be tuned by varying the guy stiffness, the guy attachment point on the tower, the tower and mass stiffness, and the nacelle/rotor/power train masses.

Christie, R. J.

1982-03-01

41

Wind Tunnel Experimental Study on Effect of Nuclear Power Plant Cooling Tower on Radioactive Plume Dispersion  

Microsoft Academic Search

A wind tunnel experiment for the effect of the cooling tower in an inland nuclear power plant on flow and dispersion of radioactive plume was introduced in paper. The model scale is 1:1500. Measurements of mean flow, turbulence characteristics and wake structure with different orientations of cooling tower and other buildings were made by using an X-array hot wire probe.

Qingdang Qiao; Zhanjie Guo; Runying Wang; Rentai Yao; Dongpeng Guo; Dan Fan; Xiaofen Hou

2011-01-01

42

Tower and Rotor Blade Vibration Test Results for a 100-Kilowatt Wind Turbine.  

National Technical Information Service (NTIS)

Because the steel truss tower and rotor blades are major structural subassemblies of the ERDA-NASA 100-kW wind turbine, the predominant natural frequencies and mode shapes for the tower and the rotor blades were determined by testing. The tests on the tow...

B. S. Linscott W. R. Shapton D. Brown

1976-01-01

43

Investigation of wind inflow data at WERC site from a 50 meter tower  

NASA Astrophysics Data System (ADS)

In December of 2011 the University Of Wyoming Wind Energy Research Center (WERC) installed a 50 meter meteorological tower in the Laramie Valley. The tower was configured to assess the surface layer characteristics of a region surrounded by varying terrain features in all directions. The overall goal of the WERC tower is to investigate wind turbine inflow characteristics as seen at the WERC site. This thesis presents the first results and analysis of the tower data over the first 10 months of operation (14 Dec. 2011 - 22 Oct. 2012). Five minute averaged data was used to describe general inflow characteristics of the area. Measurements taken at a 10 Hz sampling rate were used to accurately characterize the turbulence under various wind speed and stability situations. A feasibility study is also discussed to indicate the viability of wind energy production in the Laramie valley.

Lehman, Nathan W.

44

Boundary layer wind structure from observations on a 325 m tower  

Microsoft Academic Search

This paper is concerned with vertical distributions of mean wind speed and atmospheric turbulence characteristics over a typical urban area. The wind data were measured from more than 30 anemometers installed at 15 different height levels on the 325m high Beijing Meteorological Tower during numerous windstorms. Profiles of mean wind speed are presented based on the field measurements and are

Q. S. Li; Lunhai Zhi; Fei Hu

2010-01-01

45

EERE News: World Trade Center's Freedom Tower to Feature Wind Turbines  

NSDL National Science Digital Library

The DOE Office of Energy Efficiency and Renewable Energy posts a weekly electronic newsletter. This January 7, 2004 issue of features a story about the wind turbines which will be part of the forthcoming Freedom Tower to be located at the site of the World Trade Center. The story includes links to the press release from the architects, images of the Freedom Tower design, as well as images of the proposed wind turbine installation.

46

The Impact of Tower Shadow, Yaw Error, and Wind Shears on Power Quality in a Wind–Diesel System  

Microsoft Academic Search

To study the impact of aerodynamic aspects of a wind turbine (WT) (i.e., tower shadow, wind shears, yaw error, and turbulence) on the power quality of a wind-diesel system, all electrical, mechanical, and aerodynamic aspects of the WT must be studied. Moreover, the contribution of the diesel generator system and its controllers should be considered. This paper describes how the

Roohollah Fadaeinedjad; Gerry Moschopoulos; Mehrdad Moallem

2009-01-01

47

Wind Climate Analyses for a 61-M Tower in the Southeast  

SciTech Connect

The Savannah River Technology Center's (SRTC) Atmospheric Technologies Group (ATG) has operated nine 61-m tower sites including the Central Climatology (CC) tower which is located near the center of the Savannah River Site (SRS) since 1985. Data from the weather instruments on this tower have provided answers to questions involving risk analyses, dose studies, forecast verifications, and wind/temperature conditions during extreme events and planned tests. Most recently, data from these towers are being used for initial and boundary conditions for computationally intensive numerical simulations using mesoscale forecasting models that are run on a three-hourly basis by ATG for SRS and the surrounding vicinity. We found that a series of wind roses based on relatively short time scales (from two weeks to one hour) were a convenient method to depict the predominant wind speeds and directions at anemometer sites in the Southeast operated by the NWS. That report also revealed some interesting spatial and temporal relationships among thirteen NWS stations in the Carolinas, Georgia, and Florida. Our study here will focus on the CC tower to show changes in the wind speed and direction distributions with height during diurnal and annual cycles. This study will concentrate on mean wind speed and direction statistics.

Weber, A.H.

2003-11-24

48

Optimization research on the structure of horizontally-arranged indirect air-cooling tower under strong wind condition  

NASA Astrophysics Data System (ADS)

Strong wind has a significant impact on the heat radiation of the air-cooling system. In this research, a numerical calculation model of 2×1000MW horizontally arranged air-cooling tower is established to simulate the flow distribution and heat exchanging capability of three different structures-horizontally-arranged indirect air-cooling tower, tower with guide wall outside, and tower with a cross wall inside-under high-speed wind and extreme-speed wind conditions. The result reveals that the structure with the guide wall outside the tower only works under strong wind condition while the structure with cross wall inside shows the anti-wind capability under both high-speed wind and extreme-speed wind conditions.

Chen, Guoyong; Gu, Hongfang; Wang, Haijun; Qin, Yongbo

2013-07-01

49

Recycled Towers  

NSDL National Science Digital Library

Students learn about material reuse by designing and building the strongest and tallest towers they can, using only recycled materials. They follow design constraints and build their towers to withstand earthquake and high wind simulations.

Integrated Teaching And Learning Program

50

Hydrogen storage in wind turbine tower — A review  

Microsoft Academic Search

Wind energy is clean, renewable, and often rises to the top of the list when considering “green” energy alternatives. Many challenging issues also arise when considering wind energy. The biggest issue, some say, is that wind energy is not reliable, dependable, or consistent enough to be taken seriously; any more than on small scale applications. Due to the inconsistent nature

B. R. R. Bapu; J. Karthikeyan; K. V. K. Reddy

2010-01-01

51

Voltage Sag Impact on Wind Turbine Tower Vibration  

Microsoft Academic Search

In order to study the voltage sag impact on mechanical vibration of wind turbine structure a detailed model that considers all three electrical, mechanical and aerodynamic aspects of the wind turbine must be considered. A drawback of many works in the area of wind turbine simulation is that either a very simple mechanical model is used with a detailed electrical

Roohollah Fadaeinedjad; Gerry Moschopoulos; Mehrdad Moallem

2007-01-01

52

Recent Results From the NOAA/ESRL GMD Tall Tower Network  

NASA Astrophysics Data System (ADS)

We will present a summary of new results from NOAA Earth System Research Laboratory`s Tall Tower greenhouse gas monitoring network. The tower network is operated by the Global Monitoring Division, which also maintains the global Cooperative Air Sampling network and a network of aircraft profiling sites over North America. Tall tower CO2 mixing ratio measurements are sensitive to upwind fluxes over scales of hundreds of kilometers, and the primary objective of the tower network is to obtain regionally representative carbon flux estimates for the North American continent. Mixing ratios of CO2 and CO are measured semi-continuously at the towers, and the KWKT-TV tower site near Moody, TX has recently also been equipped with sensors to measure radon and O3. Daily flask samples are collected at the KWKT tower and analyzed for CO2, CO, CH4, SF6, N2O, H2, stable isotopes of CO2 and CH4, COS, and a variety of halocarbon and hydrocarbon species. Daily flask sampling will be implemented at all tower sites within the next few years. We have used the Stochastic Time Inverted Lagrangian Transport (STILT) model to investigate upwind influences on the tower observations. CO measurements provide an indicator of polluted air masses, and we will present a summary of the frequency and origin of pollution events observed at the towers. We will present an analysis of the primary factors contributing to observed CO2 variability along with average seasonal and diurnal cycles of CO2 at the tower sites. Tower measurements are being used to evaluate atmospheric transport models in the context of the Transcom Continuous experiment and are an important constraint for CO2 data assimilation systems that produce regional to global carbon flux estimates with up to weekly resolution.

Andrews, A. E.; Tans, P. P.; Peters, W.; Hirsch, A.; Sweeney, C.; Petron, G.; Kofler, J.; Zhao, C.; Masarie, K.; Wofsy, S. C.; Matross, D. M.; Mahadevan, P.; Longo, M.; Gerbig, C.; Lin, J. C.

2006-12-01

53

Dynamic performance of cable-stayed bridge tower with multi-stage pendulum mass damper under wind excitations — II: Experiment  

NASA Astrophysics Data System (ADS)

The possibility of using a multi-stage pendulum mass damper (MSPMD) to control wind-induced vibration of a single column tower of a cable-stayed bridge during construction was studied theoretically in part I of this work. In this paper, the performance of the MSPMD for reducing bridge tower vibration is studied experimentally. A MSPMD model and a tower model of the bridge with geometry scaling of 1:100 were designed and manufactured. Calibration of the MSPMD model with different wire lengths is conducted to verify the analytical model of the damper. A series of tests for the uncontrolled freestanding tower, tower with cables, and tower with MSPMD model are then performed under harmonic and white noise excitations. The experimental results show that the responses of the tower model significantly decrease with the installation of the MSPMD model, which demonstrates the effectiveness of the MSPMD to mitigate the vibration of the bridge tower.

Guo, Anxin; Xu, Y. L.; Li, Hui

2007-12-01

54

Approximate Method for Calculating Free Vibrations of a Large-Wind-Turbine Tower Structure.  

National Technical Information Service (NTIS)

A set of ordinary differential equations are derived for a simplified structural dynamic lumped-mass model of a typical large-wind-turbine tower structure. Dunkerley's equation is used to arrive at a solution for the fundamental natural frequencies of the...

B. S. Linscott S. C. Das

1977-01-01

55

Approximate Method for Calculating Free Vibrations of a Large-Wind-Turbine Tower Structure.  

National Technical Information Service (NTIS)

A set of ordinary differential equations were derived for a simplified structural dynamic lumped-mass model of a typical large-wind-turbine tower structure. Dunkerley's equation was used to arrive at a solution for the fundamental natural frequencies of t...

S. C. Das B. S. Linscott

1977-01-01

56

NREL National Wind Technology Center (NWTC): M2 Tower; Boulder, Colorado (Data)  

DOE Data Explorer

The National Wind Technology Center (NWTC), located at the foot of the Rocky Mountains near Boulder, Colorado, is a world-class research facility managed by NREL for the U.S. Department of Energy. NWTC researchers work with members of the wind energy industry to advance wind power technologies that lower the cost of wind energy through research and development of state-of-the-art wind turbine designs. NREL's Measurement and Instrument Data Center provides data from NWTC's M2 tower which are derived from instruments mounted on or near an 82 meter (270 foot) meteorological tower located at the western edge of the NWTC site and about 11 km (7 miles) west of Broomfield, and approximately 8 km (5 miles) south of Boulder, Colorado. The data represent the mean value of readings taken every two seconds and averaged over one minute. The wind speed and direction are measured at six heights on the tower and air temperature is measured at three heights. The dew point temperature, relative humidity, barometric pressure, totalized liquid precipitation, and global solar radiation are also available.

Jager, D.; Andreas, A.

57

FDTD Analysis of the Current Distribution within the Grounding System for a Wind Turbine Generation Tower Struck by Lightning  

NASA Astrophysics Data System (ADS)

Transient current distribution within the grounding system for a wind-turbine-generation tower of height 61m struck by lightning has been calculated using the finite-difference time-domain (FDTD) method. The grounding grid for the lightning-struck tower considered in this paper is connected electrically via an insulated wire to one neighboring-tower grounding grid located 50m away from it. High-frequency components of a lightning current tend to flow in ground through the grounding grid of the lightning-struck tower, and they become larger with increasing the ground conductivity. Relatively-lower-frequency components of the lightning current flow in ground through each of the two grounding grids roughly in inverse proportion to the grounding resistance of each grid. For example, when two identical grounding grids for the lightning-struck tower and the neighboring tower are buried in the same ground, about 50% of the lightning current flows in the grounding grid for the neighboring tower via the insulated wire connecting these two grounding grids. When the grounding resistance of the neighboring tower is about 1/4 of that for the lightning-struck tower, about 4/5 of the lightning current flows in the neighboring-tower grounding grid. This agrees well with the trend shown by Nagaoka et al. from their measurement in the grounding system for an actual wind-turbine-generation tower struck by natural lightning.

Nagao, Mitsuhiro; Nagaoka, Naoto; Baba, Yoshihiro; Ametani, Akihiro

58

Investigation on the impact of the environment wind velocity on the indirect air-cooling tower performance  

NASA Astrophysics Data System (ADS)

The wind velocity plays a crucial role in the operation characteristic of indirect cooling tower. In this paper a 2×330MW vertical arrangement indirect air-cooled system was taken as research object, and numerical simulation method was used to analyze the relative influence of the wind speed, ranging from 4m/s to 18m/s, on the outlet water temperature of cooling tower, the outlet air temperature of radiator, the facing wind speed of the fan segment and on the outlet air speed of the cooling tower. The result shows that the impact of the natural wind speed on the cooling tower efficiency varies greatly and this impact increases as the wind speed increases.

Qin, Yongbo; Gu, Hongfang; Wang, Haijun; Chen, Guoyong

2013-07-01

59

Dynamics of wakes downstream of wind turbine towers  

NASA Technical Reports Server (NTRS)

The near field wakes downstream of circular cylinders and of 12 sided cylinders were surveyed in a wind tunnel. Local velocity and velocity deficit diagrams are presented. The variation of turbulence in the wake was surveyed and the frequency of the periodic component of wake motion was determined. Differences between wakes of circular cylinders and of 12 sided cylinders are discussed. Also effects of strakes, orientation of the 12 sided cylinders, and rounding of the corners are noted.

Snyder, M. H.; Wentz, W. H., Jr.

1981-01-01

60

The IAUC Urban Flux Network - An international network of micrometeorological flux towers in urban ecosystems  

NASA Astrophysics Data System (ADS)

Throughout the past decade, numerous research groups have put significant effort into setting up new infrastructure to directly measure fluxes between various urban ecosystems and the atmosphere using micrometeorological methods - mainly eddy covariance of energy, water vapour, carbon dioxide, and aerosols. More and more long-term sites are installed in areas considered ‘typical’ for selected urban developments to quantify the impact of urban form and management on energy and greenhouse gas exchange and to support the biogeochemical modeling of urban ecosystem. Only few tall towers in urban areas are included in the FLUXNET database (http:// www.fluxnet.ornl.gov/). Most urban sites are not suitable for FLUXNET as virtually no urban site is focusing on the quantification of annual net ecosystem exchange (NEE). Urban flux-tower projects rather focus on urban-specific processes such as the role of managed urban vegetation, modified soils, urban water use, fossil-fuel emissions, the release of air pollutants, and/or anthropogenic heat fluxes. Therefore the International Association on Urban Climate (IAUC) has established the “Urban Flux Network” with the goal to network research groups and activities in the international urban flux community. The IAUC provides a simple, geographical database (http://www.urban-climate.org/) with the objective to collect and share information about ongoing and discontinued micrometeorological tower sites located in urban environments. Currently the database hosts over 30 towers from 5 continents. Example data from selected towers will demonstrate the potential of using data from a variety of urban ecosystems to quantify density effects, or the role of vegetation structure and irrigation management on the exchange of primarily energy and carbon dioxide.

Christen, A.; Grimmond, S.; Roth, M.; Pardyjak, E.

2009-12-01

61

An evaluation of 915-MHz radar wind profiler/RASS by tower and sodar measurements  

NASA Astrophysics Data System (ADS)

The accuracy and precision of the 915-MHz low-atmosphere wind profiler/RASS have been investigated through comparisons with other better-understood instruments such as rawinsonde (Strauch et al., 1987 and May et al., 1989), sodar (Neff and Wilczak, 1993), and tower instruments (Ye et al., 1993). These studies have provided useful information as well as confidence in the performance of this new technology in boundary-layer research and monitoring. However, because the accuracy of the profiler/RASS measurements depends to a large degree on the strength and homogeneity of small-scale turbulence and the amount of moisture in the atmosphere, the performance of the profiler may change significantly from one environment to another. As the radar wind profiler/RASS technology becomes more widely applied to a variety of research applications and moves toward operational wind, temperature, and eventually flux profiling, it is crucial to quantify its performance under different environmental and meteorological conditions. South-central Washington is a semi-arid shrub-steppe environment with an average annual precipitation of only about 15 cm, which is significantly different from the other locations where comparative studies have been conducted. The performance of the RADIAN 915-MHz wind profiler/RASS in such an environment was evaluated using data from standard instruments mounted on a 120-m meteorological tower and a nearby sodar at the Hanford Meteorological Station. The results of this evaluation are presented in this paper.

Zhong, S.; Shaw, W. J.; Hubbe, J. M.

1994-08-01

62

Dynamic performance of cable-stayed bridge tower with multi-stage pendulum mass damper under wind excitations — I: Theory  

NASA Astrophysics Data System (ADS)

In this paper, wind-induced vibration control of a single column tower of a cable-stayed bridge with a multi-stage pendulum mass damper (MSPMD) is investigated. Special attention is given to overcoming space limitations for installing the control device in the tower and the effect of varying natural frequency of the towers during construction. First, the finite element model of the bridge during its construction and the basic equation of motion of the MSPMD are introduced. The equation of motion of the bridge with the MSPMD under along-wind excitation is then established. Finally, a numerical simulation and parametric study are conducted to assess the effectiveness of the control system for reducing the wind-induced vibration of the bridge towers during construction. The numerical simulation results show that the MSPMD is practical and effective for reducing the along-wind response of the single column tower, can be installed in a small area of the tower, and complies with the time-variant characteristics of the bridge during its entire construction stage.

Guo, Anxin; Xu, Youlin; Li, Hui

2007-09-01

63

US Wind Farmers Network  

SciTech Connect

Through this program Windustry representatives have produced, widely used, and distributed new materials and have participated in a wide variety of wind energy events, meetings, and conferences. In this work Windustry representatives have sought to reach a broad audience and grow interest and enthusiasm for wind energy. At the same time, Windustry representatives have sought to provide tools, detailed case studies, and other technical resources that deepen Windustry constituency's knowledge of wind energy options. All of this has served to facilitate development of many actual wind energy projects, particularly projects that emphasize local and community benefits.

Lisa Daniels; DOE Project Officer - Keith Bennett

2005-04-15

64

Wind shear for large wind turbine generators at selected tall tower sites  

SciTech Connect

The objective of the study described in this report is to examine the nature of wind shear profiles and their variability over the height of large horizontal-axis wind turbines and to provide information on wind shear relevant to the design and opertion of large wind turbines. Wind turbine fatigue life and power quality are related through the forcing functions on the blade to the shapes of the wind shear profiles and their fluctuations over the disk of rotation.

Elliott, D.L.

1984-04-01

65

Cyclic loading test of friction-type reinforcing members upgrading wind-resistant performance of transmission towers  

Microsoft Academic Search

Two types of friction-type reinforcing members (FRM) are proposed for the purpose of upgrading wind resistant performance of a transmission tower and verified through cyclic loading tests. First, a suitable installation scheme of the FRM is investigated through numerical analysis. Tower-leg-reinforcing type and brace type installation schemes are examined, and numerical analysis shows that the latter is more effective due

Ji-Hun Park; Byoung-Wook Moon; Kyung-Won Min; Sung-Kyung Lee; Chee Kyeong Kim

2007-01-01

66

Influence of Multiple Cutouts on the Buckling of Large-Scale Thin-Walled Cylindrical Shells of Desulphurizing Tower under Wind Loading  

Microsoft Academic Search

The desulphurizing tower used in the power plant is the key environmental protection facility to eliminate the air pollution. Multiple cutouts are opened on the tower wall because of the technology requirement. The presence of multiple cutouts will influence the stability of tower under wind loading. On the project background of the large-scale thin-walled cylindrical shells of a practical desulphurizing

Dengfeng Wang; Yuanqing Wang; Yongjiu Shi; Pingzhou Cao

2011-01-01

67

Windmill tower  

SciTech Connect

A windmill tower supports a propeller and a platform that in turn supports a propeller feather control system and a generator system. The entire tower rotates at its base under changes in wind direction so the rotating propeller is constantly maintained upwind of the tower. The tower is a rigid structure that withstands cyclic thrust and torque loading sufficiently to reduce resonant vibrations of the tower as the propeller rotates under the influence of the wind. The resonant frequency of the tower can be higher than the passing frequency of the rotating propeller blades. The tower includes a pair of generally upright fore legs that converge upwardly toward a first apex on the propeller axis of rotation near the front of the platform immediately behind the propeller hub. A diagonal bracing strut extends downwardly from the first apex away from the plane of the fore legs and toward the rear of the tower. The bottoms of the fore legs and the diagonal bracing strut are rigidly interconnected by base plane truss members. A pair of upwardly converging aft legs extend diagonally upwardly from the bottoms of the fore legs toward a second apex aft of the first apex at the rear of the platform. At regular vertical intervals, stiffening trusses add rigidity to the main upright members of the tower structure. The natural frequency of the tower is raised by the fore legs and the diagonal bracing strut being interconnected in a rigid base plane truss. The diagonal bracing strut resists thrust loading on the tower, and the fore legs and aft legs resist torsional forces produced at the top of the tower.

Schachle, C.; Schachle, E.C.; Schachle, J.R.; Schachle, P.J.

1982-04-06

68

Space-Time VMS Computation of Wind-Turbine Rotor and Tower Aerodynamics  

NASA Astrophysics Data System (ADS)

This thesis is on the space{time variational multiscale (ST-VMS) computation of wind-turbine rotor and tower aerodynamics. The rotor geometry is that of the NREL 5MW offshore baseline wind turbine. We compute with a given wind speed and a specified rotor speed. The computation is challenging because of the large Reynolds numbers and rotating turbulent ows, and computing the correct torque requires an accurate and meticulous numerical approach. The presence of the tower increases the computational challenge because of the fast, rotational relative motion between the rotor and tower. The ST-VMS method is the residual-based VMS version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method, and is also called "DSD/SST-VMST" method (i.e., the version with the VMS turbulence model). In calculating the stabilization parameters embedded in the method, we are using a new element length definition for the diffusion-dominated limit. The DSD/SST method, which was introduced as a general-purpose moving-mesh method for computation of ows with moving interfaces, requires a mesh update method. Mesh update typically consists of moving the mesh for as long as possible and remeshing as needed. In the computations reported here, NURBS basis functions are used for the temporal representation of the rotor motion, enabling us to represent the circular paths associated with that motion exactly and specify a constant angular velocity corresponding to the invariant speeds along those paths. In addition, temporal NURBS basis functions are used in representation of the motion and deformation of the volume meshes computed and also in remeshing. We name this "ST/NURBS Mesh Update Method (STNMUM)." The STNMUM increases computational efficiency in terms of computer time and storage, and computational exibility in terms of being able to change the time-step size of the computation. We use layers of thin elements near the blade surfaces, which undergo rigid-body motion with the rotor. We compare the results from computations with and without tower, and we also compare using NURBS and linear finite element basis functions in temporal representation of the mesh motion.

McIntyre, Spenser W.

69

Space-time VMS computation of wind-turbine rotor and tower aerodynamics  

NASA Astrophysics Data System (ADS)

We present the space-time variational multiscale (ST-VMS) computation of wind-turbine rotor and tower aerodynamics. The rotor geometry is that of the NREL 5MW offshore baseline wind turbine. We compute with a given wind speed and a specified rotor speed. The computation is challenging because of the large Reynolds numbers and rotating turbulent flows, and computing the correct torque requires an accurate and meticulous numerical approach. The presence of the tower increases the computational challenge because of the fast, rotational relative motion between the rotor and tower. The ST-VMS method is the residual-based VMS version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method, and is also called "DSD/SST-VMST" method (i.e., the version with the VMS turbulence model). In calculating the stabilization parameters embedded in the method, we are using a new element length definition for the diffusion-dominated limit. The DSD/SST method, which was introduced as a general-purpose moving-mesh method for computation of flows with moving interfaces, requires a mesh update method. Mesh update typically consists of moving the mesh for as long as possible and remeshing as needed. In the computations reported here, NURBS basis functions are used for the temporal representation of the rotor motion, enabling us to represent the circular paths associated with that motion exactly and specify a constant angular velocity corresponding to the invariant speeds along those paths. In addition, temporal NURBS basis functions are used in representation of the motion and deformation of the volume meshes computed and also in remeshing. We name this "ST/NURBS Mesh Update Method (STNMUM)." The STNMUM increases computational efficiency in terms of computer time and storage, and computational flexibility in terms of being able to change the time-step size of the computation. We use layers of thin elements near the blade surfaces, which undergo rigid-body motion with the rotor. We compare the results from computations with and without tower, and we also compare using NURBS and linear finite element basis functions in temporal representation of the mesh motion.

Takizawa, Kenji; Tezduyar, Tayfun E.; McIntyre, Spenser; Kostov, Nikolay; Kolesar, Ryan; Habluetzel, Casey

2014-01-01

70

Comparison of wind pressure measurements on tower-like structure obtained from full-scale observation, wind tunnel test, and the CFD technology  

Microsoft Academic Search

Full-scale measurements, wind tunnel tests and CFD calculations have been carried out on pressure measurements on a tower-like structure. This paper presents the comparison of pressure measurements among these three methods. The mean wind pressure coefficients obtained from the wind tunnel tests are fairly close to those of the full-scale measurements after the reference pressure is taken into consideration. RMS

Morimasa Watakabe; Masamiki Ohashi; Hisashi Okada; Yasuo Okuda; Hitomi Kikitsu; Shinji Ito; Yasuhito Sasaki; Kenji Yasui; Kiyomine Yoshikawa; Masao Tonagi

2002-01-01

71

Does the European eddy flux tower network represent the climatic and ecophysiological diversity of Europe?  

NASA Astrophysics Data System (ADS)

In analyzing the increase of greenhouse gas concentration in terrestrial atmosphere, the studies about the role of vegetation in the carbon exchange regulation are relevant. In this respect, a network using the eddy covariance technique to measure CO2 and H2O exchanges between terrestrial ecosystems and atmosphere, has been established. When the network was established, 16 towers all located in forest ecosystems were maintained. In the past 15 years, the network grew and the current Carboeurope-IP monitoring network consists of more than 100 flux towers (www.carboaurope.org) located all over Europe aiming to represent the diversified of geographic regions, climatic and vegetation characteristics (Plant Functional Types). Because the growth of the network was driven by funding and administrative issues rather than scientific needs, we evaluated, in retrospective, the representativeness of the current network based on climatic and ecophysiological characteristics of the sites and the European territory. We used a cluster approach based on the distance matrix of Self Organizing Maps (SOM) (Kohonen 2001), where the SOM was trained with 21 variables describing main meteorological and productivity characteristics and their inter-annual and seasonal variability of the European territory. A separate SOM was trained for each PFT and the representativeness of eddy towers sites has been evaluated on the basis of their positions on the SOM clusters map (i.e. the 21-D variable-space). The main underlying assumption was that the number of clusters within each PFT was similar to the current number of towers. The analysis showed that the current network is representing the European domain quite well in respect to the variables considered, although North-Eastern and South-Eastern climatic and ecosphysiological conditions are poorly sampled for several PFT. The same approach was used to propose a new tower arrangement that maximizes the network representativeness. Further, our results shown that use of data-driven clustering techniques like SOM can contribute to the evaluation of network representativeness with important impact in network design and analysis of model simulations based on the data derived from this monitoring network. Kohonen T (2001) Self-Organizing Maps. Springer-Verlag, Berlin.

Canfora, E.; Papale, D.; Luyssaert, S.; Sulkava, M.

2009-04-01

72

The PNL single-tower measurement model of rotationally sampled turbulent wind, with user's guide for STRS2PC  

SciTech Connect

This report describes a single-tower rotationally sampled wind model, STRS-2, that approximates a set of time series of turbulent wind experienced by individual points rotating in circles in a crosswind plane using measurements from anemometers arrayed vertically along a single line. The purposes of the model are (1) to use turbulence measurements made economically from conventional single-tower arrays of anemometers, (2) to incorporate measures characteristics of the wind at specific sites under consideration for operation of wind turbines, spanning the height range if interest, and (3) to estimate the unmeasured turbulence characteristics in the crosswind plane that spans the disk of the rotor blades. 17 refs., 15 figs., 5 tabs.

Connell, J.R.; Morris, V.R.; Powell, D.C.; Gower, G.L.

1988-06-01

73

Wind energy conversion. Volume IX. Aerodynamics of wind turbine with tower disturbances  

Microsoft Academic Search

Lifting line theory which is the counterpart of Prandtl's lifting line theory for rotating wing is employed for the overall performance analysis of a horizontal axis wind turbine rotor operating in a uniform flow. The wake system is modeled by non-rigid wake which includes the radial expansion and the axial retardation of trailing vortices. For the non-uniform flow which are

Chung

1978-01-01

74

Atmospheric CO2 and CH4 Measurement Network on Towers in Siberia  

Microsoft Academic Search

In order to estimate CO2 and CH4 fluxes at regional to sub-continental scale by an inverse model, a network of tall towers for atmospheric CO2 and CH4 measurements has been established over a region of thousand square kilometers in west Siberia. In-situ continuous measurements have been conducted at 6 stations: Berezorechka (56.17N, 84.33E) since 2002, Parabel (58.25N, 82.40E) and Igrim

K. Shimoyama; T. Machida; A. Shinohara; S. Maksyutov; M. Arshinov; D. Davydov; A. Fofonov; O. Krasnov; N. Fedoseev; B. Belan; H. Belan; G. Inoue

2006-01-01

75

Tower Mesonetwork Climatology and Interactive Display Tool  

NASA Technical Reports Server (NTRS)

Forecasters at the 45th Weather Squadron and Spaceflight Meteorology Group use data from the tower network over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) to evaluate Launch Commit Criteria, and issue and verify forecasts for ground operations. Systematic biases in these parameters could adversely affect an analysis, forecast, or verification. Also, substantial geographical variations in temperature and wind speed can occur under specific wind directions. To address these concerns, the Applied Meteorology Unit (AMU) developed a climatology of temperatures and winds from the tower network, and identified the geographical variation and significant tower biases. The mesoclimate is largely driven by the complex land-water interfaces across KSC/CCAFS. Towers with close proximity to water typically had much warmer nocturnal temperatures and higher wind speeds throughout the year. The strongest nocturnal wind speeds occurred from October to March whereas the strongest mean daytime wind speeds occurred from February to May. These results of this project can be viewed by forecasters through an interactive graphical user interface developed by the AMU. The web-based interface includes graphical and map displays of mean, standard deviation, bias, and data availability for any combination of towers, variables, months, hours, and wind directions.

Case, Jonathan L.; Bauman, William H., III

2004-01-01

76

Lightning Protection Effect of Lightning Tower Set Up in Wind Power Station based on Upward Leader Progression Model  

NASA Astrophysics Data System (ADS)

The wind power stations on the coast of the Japan Sea have high risks to be damaged by upward lightning in winter, so that sometimes lightning towers have been set up as a countermeasure. The upward leader progression model (ULP model) is proposed as a prediction method of lightning protective effect of upward lighting in winter. However, there are only few observational data, so that validation examples of lightning shielding effect using this prediction method are few. One wind turbine and one lightning tower have been set up at the Uchinada wind power station, and the lightning observations have been continued and 77 observational data have been reported so far. In this paper, we have made a comparative study of the lightning ratios estimated by ULP model and by observational data. Although there were some cases that had big differences in lightning ratio due to the wind direction, the final result of general lightning ratio was almost the same. Regarding the wind direction distribution used in ULP model, there were some differences in number between proposed wind direction distribution and observed wind direction distribution. However, it doesn't have a great impact on the calculation of the lightning ratio due to the differences in this paper.

Sakata, Tadashi; Yamamoto, Kazuo; Sekioka, Shozo; Yokoyama, Shigeru

77

Atmospheric CO2 and CH4 Measurement Network on Towers in Siberia  

NASA Astrophysics Data System (ADS)

In order to estimate CO2 and CH4 fluxes at regional to sub-continental scale by an inverse model, a network of tall towers for atmospheric CO2 and CH4 measurements has been established over a region of thousand square kilometers in west Siberia. In-situ continuous measurements have been conducted at 6 stations: Berezorechka (56.17N, 84.33E) since 2002, Parabel (58.25N, 82.40E) and Igrim (63.20N, 64.48E) since 2004, Demyanskoe (59.78N, 70.87E) and Noyabrsk (63.43N, 76.76E) since 2005, and Yakutsk (62.83N, 129.35E) in east Siberia since 2005. Over next two years, installations of 4 more stations are planned. This study provides some results of observation from this network. Seasonal cycles of CO2 showed quite similar trends in growing season (May to September) among the west Siberian sites. The remarkable decrease of CO2 concentration occurred in early May and the seasonal minimum was observed between July and August. On the other hand, the short-term (from several days to week) variations in CO2 concentrations were quite different among the sites, particularly during the growing season. Rather large variation of more than 25 ppm within a week was observed during winter. The changes in CO2 concentrations at the nearby sites were almost identical. Monthly mean values of CO2 during the growing season were relatively higher at the northern sites than at southern sites. These observational results evidentially reflected the regional characteristics of CO2 flux variation, transportation, and mixing process. Daily cycles of CH4 in summer showed nocturnal increase and diurnal decrease which was due to emission of CH4 from wetland accumulated over night, and diurnal convective mixing. Relatively high concentrations of CH4 were observed in winter and summer. Because there is one of the world's vastest wetland in western Siberia, the peak of CH4 in summer implies the significant role of CH4 emissions from the west Siberian wetland to the atmosphere. On the other hand, an exceptionally high concentration of CH4 of more than 3 ppm was observed in several sites. It occurred irrespective of time of a day but was associated with the definite wind direction. This may be linked to a strong point source of CH4 such as the leakage of natural-gas from pipeline or compressor station located near the observation sites. Thus, the data presented in this study can contribute to the future effort to detect the leakage point in the pipeline using satellite data.

Shimoyama, K.; Machida, T.; Shinohara, A.; Maksyutov, S.; Arshinov, M.; Davydov, D.; Fofonov, A.; Krasnov, O.; Fedoseev, N.; Belan, B.; Belan, H.; Inoue, G.

2006-12-01

78

Bird Strikes and Electrocutions at Power Lines, Communication Towers, and Wind Turbines: State of the Art and State of the Science - Next Steps Toward Mitigation1  

Microsoft Academic Search

Migratory birds suffer considerable human-caused mortality from structures built to provide public serv- ices and amenities. Three such entities are increasing nationwide: communication towers, power lines, and wind turbines. Communication towers have been grow- ing at an exponential rate over at least the past 6 years. The U.S. Fish and Wildlife Service is especially con- cerned about growing impacts to

Albert M. Manville

2005-01-01

79

WindPACT Turbine Design Scaling Studies Technical Area 3 -- Self-Erecting Tower and Nacelle Feasibility: March 2000--March 2001  

SciTech Connect

The United States Department of Energy (DOE), through the National Renewable Energy Laboratory (NREL), has implemented the Wind Partnerships for Advanced Component Technologies (WindPACT) program to explore advanced technologies for improving the reliability and cost-effectiveness of wind energy technology. Global Energy Concepts (GEC) prepared this report on self-erecting towers as part of the WindPACT program. The objectives of the work were to identify potential methods for erecting wind turbine towers without the use of large conventional cranes, establish the most promising methods, and compare the costs of the most promising methods to the costs of conventional cranes.

Global Energy Concepts, LLC

2001-05-31

80

A virtual tall tower network for understanding continental sources and sinks of CO2  

SciTech Connect

Our understanding of the North American terrestrial carbon cycle is limited by both a lack of continental atmospheric CO2 data, and by a need for methods to interpret these and other continental data with confidence. In response to this challenge a rapid expansion of the N. American carbon cycle observational network is underway. This expansion includes a network of continuous, continental CO2 mixing ratio observations being collected at a subset of AmeriFlux towers. Progress in developing this resource includes instrument development, site installation, calibration and intercalibration efforts, and initiation of a uniform data product. Progess in applying these data include proposed methods for interpreting surface layer measurements in atmospheric inversions (the virtual tall towers approach), examination of coherence patterns in continental mixing ratios in response to weather and climate, and application of these mixing ratio measurements in formal atmospheric inversions. Future work will merge these methods with interpretation of flux towers observations of terrestrial carbon fluxes in an effort to create a single coherent diagnosis of North American terrestrial carbon fluxes over a multi-year period.

Davis, K.J.; Richardson, S.J.; Miles, N.L.

2007-03-09

81

An analysis of maximum vertical gusts recorded at NASA's 150-meter ground winds tower facility at Kennedy Space Center, Florida  

NASA Technical Reports Server (NTRS)

A statistical summary is presented of vertical wind speed data recorded at NASA's 150-Meter Ground Winds Tower Facility on Merritt Island, Kennedy Space Center, Florida. One year of continuous around-the-clock vertical wind speed measurements processed by the Automatic Data Acquisition System (ADAS) is classified as a function of tower level (10, 18, 60, and 150 meters) and period of reference day, month, season: winter (October through March) and summer (April through September), and annual. Intensity, frequency, time of occurrence, prevailing conditions, etc., of the daily maximum vertical gusts (i.e., updraft and downdraft) are determined. The results are compared with the vertical gusts associated with the daily maximum horizontal gust. The intent of this summarization of vertical wind speed data is to provide a general description of wind flow in the lower 150 meters of the atmosphere for the identification of hazards involved in wind shear encounters relative to ascent and descent of the Space Shuttle and conventional aircraft.

Alexander, M. B.

1977-01-01

82

Wind Speed Prediction using Artificial Neural Networks  

Microsoft Academic Search

In this paper the problem with the introduction of a large quantity of wind generators on the electric grid is presented. A method based in artificial neural networks (ANN) is used to predict the average hourly wind speed. The study starts by choosing the patterns set length to predict de wind speed. The ANN structure and the learning method are

P. M. FONTE; GONÇALO XUFRE SILVA; J. C. QUADRADO

2005-01-01

83

Finite Element Analysis of a Wind Turbine Response when the Tower and the Blades are Modeled as Distributed Parameter Systems  

NASA Astrophysics Data System (ADS)

Finite element (FE) model of a wind turbine (WT) system is constructed where the tower and the blades are assumed as distributed parameter systems, the nacelle--as a concentrated mass and the wind loading is generated from fluid simulations. The system response is simulated by a program implementation of the model and the results obtained are compared to the results from ANSYS 3-D simulations. The constructed WT model could be utilized for identification and optimization of the system parameters as well as for defining modal characteristics and generating reduced models based on the first several natural frequencies and modal shapes.

Pasheva, V.; Slavchev, Y.; Venkov, G.

2011-12-01

84

An analysis of maximum horizontal wind speeds and associated parameters recorded at NASA's 150-Meter Ground Winds Tower facility at Kennedy Space Center, Florida  

NASA Technical Reports Server (NTRS)

Continuous horizontal wind speed measurements were processed and classified as a function of tower level (10, 18, 60, and 150 meters) and period of reference day, month, season: winter (October through March) and summer (April through September), and annual. Tabulations were made of the daily maximum horizontal wind speed, time of ocurrence, and five associated parameters: mean horizontal wind speed, maximum vertical gusts (i.e., updraft and downdraft), and mean and instantaneous directions. Analyses using these data included means, extremes, standard deviations, and frequency distributions. Comparisons of intensity of maximum horizontal wind speeds determined in this year of data are made with maximum values recorded at Kennedy Space Center during another non-hurricane-occurrence year (1967) and with values during 1966 through 1972 when six hurricanes affected the area after the Ground Winds Tower facility became operational. Wind flow in the lowest 150 meters of the atmosphere was measured for the identification of hazards involved in wind shear encounter relative to ascent and descent of the space shuttle and conventional aircraft.

Alexander, M. B.

1978-01-01

85

Estimating CH4 Emissions in California Using Measurements from a Tower Network  

NASA Astrophysics Data System (ADS)

We estimate regionally resolved methane (CH4) emissions for California using a Bayesian inverse model driven by CH4 mixing ratios measured at a network of five towers across the Central Valley during 2010 - 2011. The method estimates emissions by comparing measurements with transport model predictions of CH4 signals obtained from two 0.1 degree prior emission maps: 1) seasonally varying "California-specific" emission maps, calibrated to State emission totals, and 2) the EDGAR4.2 static global emission map. Atmospheric transport is calculated from particle trajectories and surface footprints using the Weather Research and Forecasting (WRF) and Stochastic Time-Inverted Lagrangian Transport (STILT) models. Results for the 5-tower CARB-CEC-LBNL-NOAA network show that significant reductions in posterior emissions uncertainty are obtained for regions comprising ~ 90% of California's known CH4 emissions, with annually averaged emissions totaling 1.6+/-0.1 and 2.5+/-0.3 times California's inventory for the California-specific and EDGAR4.2 emissions maps, respectively. Assuming these results apply across California, total CH4 emissions account for approximately 8% - 14% of current state total greenhouse gas emissions. The magnitude and uncertainty of emissions from specific regions and source sectors (e.g., crop agriculture, waste management, livestock, and energy activities) are estimated by comparing region and source sector results obtained with the CA-specific and EDGAR4.2 emission maps.

Jeong, S.; Hsu, Y.; Andrews, A. E.; Bianco, L.; Vaca, P.; Wilczak, J. M.; Fischer, M. L.

2012-12-01

86

Wind Speeds as Measured by Cup and Sonic Anemometers and Influenced by Tower Structure.  

National Technical Information Service (NTIS)

Wind tunnel and field experiments have shown that the fast-response three-component sonic anemometer is a highly accurate wind speed sensor. When sonic anemometers were used as reference sensors for wind speed, slower response cup anemometers were found t...

M. L. Barad Y. Izumi

1970-01-01

87

Wind tunnel experiments on cooling tower plumes part I: In uniform cross flow  

SciTech Connect

Measurements of velocity and temperature field and flow visualization results are reported for an ideal case of a cooling-tower plume in the presence of a uniform cross flow for various velocity ratios, densimetric Froude numbers, and Reynolds numbers. Coherent structures in the form of jet-like, wake-like or mushroom type of vortices have been observed. The type of the structures depends primarily on the velocity ratio. As the Reynolds number increases turbulent structures appear, which carry vorticity of the same sign as the partner vortices in the low Reynolds number case. The measurements showed that there is a strong interaction between the bending over plume or jet and the wake of the cooling tower which is basically responsible for the downwash effect. The latter is generally quite strong at low velocity ratios and high Reynolds numbers. High turbulence intensities are produced in the wake of the tower for a distance 6 to 8 diameters. The plume is diluted faster as the velocity ratio increases and buoyancy decreases. In the wake region of the stack dilution increased with buoyancy.

Andreopoulos, J.

1987-01-01

88

Assessing and improving the representativeness of monitoring networks: The European flux tower network example  

NASA Astrophysics Data System (ADS)

It is estimated that more than 500 eddy covariance sites are operated globally, providing unique information about carbon and energy exchanges between terrestrial ecosystems and the atmosphere. These sites are often organized in regional networks like CarboEurope-IP, which has evolved over the last 15 years without following a predefined network design. Data collected by these networks are used for a wide range of applications. In this context, the representativeness of the current network is an important aspect to consider in order to correctly interpret the results and to quantify uncertainty. This paper proposes a cluster-based tool for quantitative network design, which was developed in order to suggest the best network for a defined number of sites or to assess the representativeness of an existing network to address the scientific question of interest. The paper illustrates how the tool can be used to assess the performance of the current CarboEurope-IP network and to improve its design. The tool was tested and validated with modeled European GPP data as the target variable and by using an empirical upscaling method (Artificial Neural Network (ANN)) to assess the improvements in the ANN prediction with different design scenarios and for different scientific questions, ranging from a simple average GPP of Europe to spatial, temporal, and spatiotemporal variability. The results show how quantitative network design could improve the predictive capacity of the ANN. However, the analysis also reveals a fundamental shortcoming of optimized networks, namely their poor capacity to represent the spatial variability of the fluxes.

Sulkava, Mika; Luyssaert, Sebastiaan; Zaehle, SöNke; Papale, Dario

2011-09-01

89

Reglering av Vindkraftverk. Kopplingen Mellan Yawroerelsen och Tornets Sidroerelse (Control of Wind Power Stations. The Coupling between Yaw Movement and Tower Lateral Resonance).  

National Technical Information Service (NTIS)

When controlling a Wind Power Station by means of yaw movement there is a coupling between the yaw movement and the poor damped lateral resonance of the tower. This coupling depends on the fact that the center of gravity of the nacelle differs from the tu...

E. Ulen

1990-01-01

90

Effect of Rotor Configuration on Guyed Tower and Foundation Designs and Estimated Costs for Intermediate-Size Horizontal-Axis Wind Turbines.  

National Technical Information Service (NTIS)

Three designs of a guyed cylindrical tower and its foundation for an intermediate size horizontal axis wind turbine generator are discussed. The primary difference in the three designs is the configuration of the rotor. Two configurations are two-blade ro...

G. R. Frederick J. R. Winemiller J. M. Savino

1982-01-01

91

On comparing three artificial neural networks for wind speed forecasting  

Microsoft Academic Search

Wind speed forecasting is critical for wind energy conversion systems since it greatly influences the issues such as the scheduling of a power system, and the dynamic control of the wind turbine. In this paper, we present a comprehensive comparison study on the application of different artificial neural networks in 1-h-ahead wind speed forecasting. Three types of typical neural networks,

Gong Li; Jing Shi

2010-01-01

92

Wind speed prediction based on genetic neural network  

Microsoft Academic Search

Short-term prediction of wind speed is important for utility of wind power. Wind generating schedules in a wind farm could be efficiently accommodated by means of precise prediction of wind speed to mitigate the impact from instable wind power on power grids. Back-propagation neural network (BPNN) is a main approach for short-term of wind speed prediction. This paper proposes using

Li Xingpei; Liu Yibing; Xin Weidong

2009-01-01

93

77 FR 33422 - Utility Scale Wind Towers From the People's Republic of China: Preliminary Affirmative...  

Federal Register 2010, 2011, 2012, 2013

...inputs purchased by a firm are delivered prices...expressly limited to firms undertaking an IPO...Medium-Sized Enterprises (SMEs) (e) Bonus for significant...Special Fund for Wind Power Manufacturing Grants 9. Government...of the two responding firms' rates. [[Page...

2012-06-06

94

Windmill tower shadow eliminator  

SciTech Connect

In a wind driven propeller system an airfoil support for the shaft of a propeller having an even number of blades extends above and below the shaft a distance at least equal to the blade length and pivots with the propeller into the wind for substantially eliminating tower shadow effects on the propeller.

Randolph, A.J.

1984-04-17

95

Quality-Controlled Wind Data from the Kennedy Space Center 915 Megahertz Doppler Radar Wind Profiler Network  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration s (NASA) Kennedy Space Center (KSC) has installed a five-instrument 915-Megahertz (MHz) Doppler Radar Wind Profiler (DRWP) system that records atmospheric wind profile properties. The purpose of these profilers is to fill data gaps between the top of the KSC wind tower network and the lowest measurement altitude of the KSC 50-MHz DRWP. The 915-MHz DRWP system has the capability to generate three-dimensional wind data outputs from approximately 150 meters (m) to 6,000 m at roughly 15-minute (min) intervals. NASA s long-term objective is to combine the 915-MHz and 50-MHz DRWP systems to create complete vertical wind profiles up to 18,300 m to be used in trajectory and loads analyses of space vehicles and by forecasters on day-of-launch (DOL). This analysis utilizes automated and manual quality control (QC) processes to remove erroneous and unrealistic wind data returned by the 915-MHz DRWP system. The percentage of data affected by each individual QC check in the period of record (POR) (i.e., January to April 2006) was computed, demonstrating the variability in the amount of data affected by the QC processes. The number of complete wind profiles available at given altitude thresholds for each profiler in the POR was calculated and outputted graphically, followed by an assessment of the number of complete wind profiles available for any profiler in the POR. A case study is also provided to demonstrate the QC process on a day of a known weather event.

Dryden, Rachel L.

2011-01-01

96

Wind power forecast using RBF network and culture algorithm  

Microsoft Academic Search

This paper proposes a novel technique that combines orthogonal least-squares (OLS) and culture algorithm (CA) to construct the radial basis function (RBF) network for the wind power forecast. By reason of the fluctuation and volatility in wind, wind power generations provide a challenge to the security and stability of the electric system, thus the growing revolution in wind energy encourages

Bei Chen; Liang Zhao; Jian Hong Lu

2009-01-01

97

Windmill tower  

SciTech Connect

A tower is hinged to a base, positioned at one side of a well, so the tower can be lowered to the ground in a direction away from the well. A lateral platform at the top of the tower extends over the well and the tower is rotatable, about a vertical axis, to swing the platform laterally and clear of the space over the well.

Smith, P.R.

1980-08-19

98

Convection towers  

DOEpatents

Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

Prueitt, Melvin L. (Los Alamos, NM)

1996-01-01

99

Convection towers  

DOEpatents

Convection towers which are capable of cleaning the pollution from large quantities of air, of generating electricity, and of producing fresh water utilize the evaporation of water sprayed into the towers to create strong airflows and to remove pollution from the air. Turbines in tunnels at the skirt section of the towers generate electricity, and condensers produce fresh water.

Prueitt, Melvin L. (Los Alamos, NM)

1995-01-01

100

South Dakota Wind Resource Assessment Network (WRAN)  

DOE Data Explorer

WRAN is a network of instrument stations sited throughout South Dakota. As of 2010, there are eleven stations, and some have been collecting data since 2001. The purpose of the WRAN:

There are several reasons why the WRAN was built. One of the most obvious is that it will allow verification of the existing resource assessments of our state. South Dakota has tremendous potential as an exporter of wind-generated electricity. There has recently been a great deal of publicity over a Pacific Northwest National Laboratories study conducted in the early 1990s that ranked the contiguous 48 states in terms of their potential to produce windpower. (Click here for the results of this study as given by the American Wind Energy Association.) South Dakota ranked fourth in that study. Also, more recently, detailed maps of the wind resource in South Dakota were produced by the National Renewable Energy Laboratory (NREL). Unfortunately, both of these studies had to rely heavily on computer-generated models and very sparse measured data, because very little appropriate measured data exists. The WRAN will provide valuable data that we anticipate will validate the NREL maps, and perhaps suggest minor adjustments.

There are many other benefits the WRAN will provide. The data it will measure will be at heights above ground that are more appropriate for predicting the performance of large modern wind turbines, as opposed to data collected at National Weather Service stations whose anemometers are usually only about 9 m (30 feet) above ground. Also, we will collect some different types of data than most wind measurement networks, which will allow a series of important studies of the potential impact and value of South Dakota's windpower. In addition, all of the WRAN data will be made available to the public via this WWWeb site. This will hopefully enable extensive informed discussion among all South Dakotans on such important topics as rural economic development and transmission system expansion. [Copied from http://sdwind.com/about/

101

Wind-induced Dynamics Of A Deep Space Network Antenna  

Microsoft Academic Search

Accurate spacecraft tracking by the NASA Deep Space Network (DSN) antennas must be assured during changing weather conditions. Wind disturbances are the main source of antenna vibrations, and consequently tracking errors. A wind force model is developed, and simulation results of wind-induced vibrations and pointing errors of the DSN antennas are presented. The antenna model includes the antenna structure, the

W. Gawronski; B. Bienkiewicz; R. E. Hill

1994-01-01

102

Using neural networks to estimate wind turbine power generation  

Microsoft Academic Search

This paper uses data collected at Central and South West Services Fort Davis wind farm (USA) to develop a neural network based prediction of power produced by each turbine. The power generated by electric wind turbines changes rapidly because of the continuous fluctuation of wind speed and direction. It is important for the power industry to have the capability to

Shuhui Li; Donald C. Wunsch; Edgar A. O'Hair; Michael G. Giesselmann

2001-01-01

103

Dynamics of Wind Generators on Electric Utility Networks  

Microsoft Academic Search

Dynamic interaction of wind-turbine-driven generators on electric utility networks was studied by computer simulation. Nonlinear representations of wind-turbine and various drive train elements and Park equation representations of synchronous and induction generators were implemented. An infinite capacity network was assumed. Time history responses for various system configurations were computed using as the input function severe wind gust data added to

CRAIGC. JOHNSON; RICHARDT. SMITH

1976-01-01

104

Optimization of Wind Turbine Performance With Data-Driven Models  

Microsoft Academic Search

This paper presents a multiobjective optimization model of wind turbine performance. Three different objectives, wind power output, vibration of drive train, and vibration of tower, are used to evaluate the wind turbine performance. Neural network models are developed to capture dynamic equations modeling wind turbine performance. Due to the complexity and nonlinearity of these models, an evolutionary strategy algorithm is

Andrew Kusiak; Zijun Zhang; Mingyang Li

2010-01-01

105

Tall tower or mountain top measurements?  

NASA Astrophysics Data System (ADS)

Resolving the regional transport and distribution of greenhouse gases in the troposphere is a key topic that challenges both modelers and experimentalists. A dense network of measurement stations would be required, in particular including measurements at high elevation to better represent the entire lower troposphere, and not only small-scale local conditions in the near-surface atmosphere. While this can be achieved by tall towers, also mountain top stations (e.g. Schauinsland, Brocken) and other stations at high elevation (e.g., Mouna Loa, Jungfraujoch) are often appropriate, due to their extended concentration footprint. However, especially over complex, mountainous terrain, the transport of atmospheric gases and their spatio-temporal distribution is difficult to predict due to the development of thermally induced local wind patterns and boundary layer processes. Therefore, the main goal of our study is to test to what extend boundary layer processes at the surface and local wind patterns close to the ground at a mountain top site influence the ambient greenhouse gas patterns compared to measurements taken at a similar altitude but at a tall tower site. To this end we use measurements from the Zugerberg mountain top station, located at a pre-Alpine mountain ridge (987 m a.s.l., 4 m above ground) exposed to the prevailing synoptic winds in Switzerland, and compare these measurements with a neighboring tall tower site (Beromünster radio broadcast tower with its top at 1014 m a.s.l., 217 m above local ground level, and ?500 m above the Swiss Plateau). The Beromünster tall tower is located at a distance of only 30 km from the mountain top station as the bird flies, and hence a direct comparison minimizes confounding factors that are not related to the tall tower vs. mountain top position of the measurements. Both stations are part of the CarboCount CH greenhouse gas observation network (http://www.carbocount.ch) initiated for long-term monitoring and modeling of greenhouse gas fluxes at a regional scale in order to achieve a better understanding about CO2 and CH4 fluxes and their response to climate. We will present first direct comparisons of measurements obtained from continuously calibrated laser absorption spectrometers to quantify the atmospheric concentrations of carbon-dioxide and methane, but also from meteorological sensors and turbulence measurements. Data from the sensors at the two stations will be used to address the following question: can a mountain top station provide similar quality of data and spatial representativeness as a tall tower for the investigation of atmospheric patterns of greenhouse gases at diurnal to seasonal scale?

Bamberger, Ines; Eugster, Werner; Oney, Brian; Brunner, Dominik; Leuenberger, Markus; Schanda, Rüdiger; Henne, Stephan; Buchmann, Nina

2014-05-01

106

Neural network based wind speed sensorless MPPT controller for variable speed wind energy conversion systems  

Microsoft Academic Search

A wind speed sensorless neural network (NN) based maximum power point tracking (MPPT) control algorithm for variable speed wind energy conversion system (WECS) is proposed. The proposed method is developed using Jordan type recurrent NN which is trained online using back-propagation. The algorithm, without requiring the knowledge of wind speed, air density or turbine parameters, generates at its output the

J. S. Thongam; P. Bouchard; R. Beguenane; I. Fofana

2010-01-01

107

Wind-induced dynamics of the deep space network antennas  

NASA Technical Reports Server (NTRS)

Accurate spacecraft tracking by the NASA Deep Space Network (DSN) antennas must be assured during changing weather conditions. Wind disturbances are the main source of tracking errors. This paper presents the development of a wind force model, and simulations of wind-induced pointing errors of DSN antennas. The antenna model includes the antenna structure, the elevation and azimuth servos, and the tracking controller. Simulation results show that pointing errors due to wind gusts are of the same order as due to wind static pressure, and that (similarly to the static wind pressure) these errors satisfy the velocity quadratic law. The methodology presented is used for wind disturbance estimation, and for design of an antenna controller with wind disturbance rejection properties.

Gawronski, W.; Bienkiewicz, B.; Hill, R. E.

1992-01-01

108

Wind-induced Dynamics Of A Deep Space Network Antenna  

NASA Astrophysics Data System (ADS)

Accurate spacecraft tracking by the NASA Deep Space Network (DSN) antennas must be assured during changing weather conditions. Wind disturbances are the main source of antenna vibrations, and consequently tracking errors. A wind force model is developed, and simulation results of wind-induced vibrations and pointing errors of the DSN antennas are presented. The antenna model includes the antenna structure, the elevation and azimuth servos, and the tracking controller. Simulation results show that pointing errors due to wind gusts are of the same order as errors due to wind steady state pressure, and that (similarly to steady state wind pressure) these errors satisfy the velocity quadratic law. The methodology presented is next used for wind disturbance estimation and for design of an antenna controller with wind disturbance rejection properties.

Gawronski, W.; Bienkiewicz, B.; Hill, R. E.

1994-11-01

109

Measured Response to Wind-Induced Dynamic Loads of a Full-Scale Scout Vehicle Mounted Vertically on a Launching Tower  

NASA Technical Reports Server (NTRS)

Winds blowing over a vehicle mounted in the launch position may induce dynamic loads which are large enough to cause structural damage. In an attempt to prevent the formation of excessive wind-induced loads on the Scout vehicle, spoiler strips of the type used on the.Vanguard vehicle were to be mounted along the upper two stages of the Scout. These spoilers were designed to blow off shortly after launch and might hit and damage the fins at the base of the Scout. In order to determine whether the spoilers planned for installation on the Scout were needed, measurements of the response to dynamic loads imposed by winds at average velocities up to approximately 33 mph were made on a full-scale Scout vehicle mounted vertically on the launching tower at the NASA Wallops Station. From these measurements, it has been concluded that the deflections and bending moments measured in response t o wind-induced dynamic loads were small and should present no structural problems to the vehicle. No significant difference exists between the responses measured with and without spoilers of the type used on the Vanguard vehicle.

Jones, George W., Jr.; Gilman, Jean, Jr.

1961-01-01

110

Evapotranspiration and energy flux observations from a global tower network with a critical analysis of uncertainties  

NASA Astrophysics Data System (ADS)

Eddy covariance studies tend to focus on the flux of carbon dioxide despite the central role of surface-atmosphere water and energy exchange in the climate system. The under-utilization of water and energy flux data is due in part to uncertainties, including the lack of observed energy balance closure. Across 173 FLUXNET sites, energy balance closure averaged 0.84 with best average closure in evergreen broadleaf forests and savannas (0.91-0.94) and worst average closure in crops, deciduous broadleaf forests, mixed forests and wetlands (0.70-0.78). The simplest explanatory model using information criteria analyses cannot exclude landscape-level heterogeneity. This finding is in empirical agreement with studies that suggest that secondary circulations, likely attributable to landscape-scale variability, are related to lack of energy balance closure, although unmeasured storage terms cannot be ruled out as a dominant contributor. Keeping uncertainties in mind, evapotranspiration and sensible heat flux follow expected seasonal patterns, and the magnitude of evapotranspiration in temperate ecosystems approached that of tropical ecosystems during the peak growing season. Latent heat exchange is constrained by an exponentially-decreasing function of vapor pressure deficit, consistent with theories of optimal stomatal behavior. Forests tended to have cooler surface temperatures when controlled for net radiation than did short-statured ecosystems, and further investigations revealed the importance of efficient heat and water vapor transport in forest canopies that are well-coupled to the atmosphere. The value of energy and water flux data from FLUXNET increases as uncertainties become better-understood, and careful interpretations of tower-level water and energy flux data will ultimately improve our understanding of the role of terrestrial ecosystems in the Earth system.

Stoy, P. C.

2012-12-01

111

Large amplitude spatial and temporal gradients in atmospheric boundary layer CO2 mole fractions detected with a tower-based network in the U.S. upper Midwest  

NASA Astrophysics Data System (ADS)

This study presents observations of atmospheric boundary layer CO2mole fraction from a nine-tower regional network deployed during the North American Carbon Program's Mid-Continent Intensive (MCI) during 2007-2009. The MCI region is largely agricultural, with well-documented carbon exchange available via agricultural inventories. By combining vegetation maps and tower footprints, we show the fractional influence of corn, soy, grass, and forest biomes varies widely across the MCI. Differences in the magnitude of CO2 flux from each of these biomes lead to large spatial gradients in the monthly averaged CO2mole fraction observed in the MCI. In other words, the monthly averaged gradients are tied to regional patterns in net ecosystem exchange (NEE). The daily scale gradients are more weakly connected to regional NEE, instead being governed by local weather and large-scale weather patterns. With this network of tower-based mole fraction measurements, we detect climate-driven interannual changes in crop growth that are confirmed by satellite and inventory methods. These observations show that regional-scale CO2 mole fraction networks yield large, coherent signals governed largely by regional sources and sinks of CO2.

Miles, Natasha L.; Richardson, Scott J.; Davis, Kenneth J.; Lauvaux, Thomas; Andrews, Arlyn E.; West, Tristram O.; Bandaru, Varaprasad; Crosson, Eric R.

2012-03-01

112

Global Network of Slow Solar Wind  

NASA Technical Reports Server (NTRS)

The streamer belt region surrounding the heliospheric current sheet (HCS) is generally treated as the primary or sole source of the slow solar wind. Synoptic maps of solar wind speed predicted by the Wang-Sheeley-Arge model during selected periods of solar cycle 23, however, show many areas of slow wind displaced from the streamer belt. These areas commonly have the form of an arc that is connected to the streamer belt at both ends. The arcs mark the boundaries between fields emanating from different coronal holes of the same polarity and thus trace the paths of belts of pseudostreamers, i.e., unipolar streamers that form over double arcades and lack current sheets. The arc pattern is consistent with the predicted topological mapping of the narrow open corridor or singular separator line that must connect the holes and, thus, consistent with the separatrix-web model of the slow solar wind. Near solar maximum, pseudostreamer belts stray far from the HCS-associated streamer belt and, together with it, form a global-wide web of slow wind. Recognition of pseudostreamer belts as prominent sources of slow wind provides a new template for understanding solar wind stream structure, especially near solar maximum.

Crooker, N. U.; Antiochos, S. K.; Zhao, X.; Neugebauer, M.

2012-01-01

113

Output Power Leveling of Wind Farm Using Pitch-angle Control with Fuzzy Neural Network  

Microsoft Academic Search

There are concerns in regards to wind power generation as its output constantly, as well as considerably, varies. This article presents a control strategy for wind farms consisting of a wind turbine with variable pitch. In order to reduce output power fluctuation of wind farms, smoothed wind-farm output power command is determined by wind condition and fuzzy neural network. In

Tomonobu Senjyu; Ryosei Sakamoto; Toshiaki Kaneko; Atsushi Yona; Toshihisa Funabashi

2008-01-01

114

Magnet Tower  

NSDL National Science Digital Library

In this activity, learners build magnetic towers to explore the forces and properties of magnets. This activity allows learners to experiment and play with magnets and feel first-hand the force of magnets pushing and pulling. Note: this activity requires the use of a drill and saw, which are not included in the cost of materials.

Workshop, Mission S.

2013-01-01

115

Balsa Towers  

NSDL National Science Digital Library

Students will build their own towers using some of the techniques they have learned. The materials will consist of balsa wood and glue. General guidelines are provided, but the students will have a lot of freedom with their design to encourage them to implement what they have learned about structural engineering.

Techtronics Program

116

Peak Wind Forecasts for the Launch-Critical Wind Towers on Kennedy Space Center/Cape Canaveral Air Force Station, Phase IV  

NASA Technical Reports Server (NTRS)

This final report describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The peak winds arc an important forecast clement for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to update the statistics in the current peak-wind forecast tool to assist in forecasting LCC violations. The tool includes onshore and offshore flow climatologies of the 5-minute mean and peak winds and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

Crawford, Winifred

2011-01-01

117

Vortex-augmented cooling tower - windmill combination  

DOEpatents

A cooling tower for cooling large quantities of effluent water from a production facility by utilizing natural wind forces includes the use of a series of helically directed air inlet passages extending outwardly from the base of the tower to introduce air from any direction in a swirling vortical pattern while the force of the draft created in the tower makes it possible to place conventional power generating windmills in the air passage to provide power as a by-product.

McAllister, J.E. Jr.

1982-09-02

118

Dual rigs conduct guyed tower drilling  

SciTech Connect

The author describes Exxon's Platform 280-A, the only existing guyed tower. It is the first ''complaint'' tower-a unit, which unlike conventional offshore platforms, can move with the forces of wind and waves. The author also describes the advantages of operating two rigs on the same platform.

Not Available

1986-04-01

119

Solar wind outflow and the chromospheric magnetic network  

PubMed

Observations of outflow velocities in coronal holes (regions of open coronal magnetic field) have recently been obtained with the Solar and Heliospheric Observatory (SOHO) spacecraft. Velocity maps of Ne7+ from its bright resonance line at 770 angstroms, formed at the base of the corona, show a relationship between outflow velocity and chromospheric magnetic network structure, suggesting that the solar wind is rooted at its base to this structure, emanating from localized regions along boundaries and boundary intersections of magnetic network cells. This apparent relation to the chromospheric magnetic network and the relatively large outflow velocity signatures will improve understanding of the complex structure and dynamics at the base of the corona and the source region of the solar wind. PMID:9933156

Hassler; Dammasch; Lemaire; Brekke; Curdt; Mason; Vial; Wilhelm

1999-02-01

120

Strategies to design and place towers for long-term ecological observations at continental scale  

NASA Astrophysics Data System (ADS)

There are numerous tower-based measurements applied in ecological science worldwide. National Ecological Observatory Network (NEON) is designing a tower-based method at 60 sites continental wide to measure abiotic drivers of ecological change, carbon and energy fluxes, and to specifically provide ecological connectively to measurements of organism ecology and connectively to remote sensed data products. Several issues come to bear when designing an infrastructure that has to accommodate different suites of measurements that have various requirements, i.e., micrometeorological, scalar flux measurements, atmospheric chemistry and boundary layer properties, and have to be objectively placed across the entire range of climate and ecosystem structures found in North America. Here, we present a comprehensive strategy that combines wind roses, footprint models, ecosystem structure, vegetation and soil maps, as well as ‘eyes on’ site visits to design and place a tower. This methodology is being used to examine the 60 preliminary tower designs in the largest ecological observatory in the world today to optimize the long-term representative measurements over the ecosystems of interests. We found that some preliminary site designs do not meet our tower science requirements due to an inadequate fetch for prevailing wind directions, extent of ecosystems boundaries, or concerns of edge effects. In these cases, the tower location shall be either micro-sited at the current locale, or moved and relocated to a different site altogether. After site specific characterization, we also found that some designed tower heights could not access the well mixed surface layer above canopy and had to be extended in design. Because wind comes from all direction at some sites, presents a particular challenge to orient a square tower. In all cases, we optimized the tower orientation to acquire the most amounts of valid data. To avoid the effects of flow distortion on measurements, the boom length (for sensor mounts) is determined to be 2-3 times of the face width of the tower on the windward side of tower. The measurement levels and heights on a tower are determined by the ecosystem type, canopy and strata. At least 4 measurement levels are expected for short statue ecosystem like grasslands, agricultural land, and prairies, whereas, 6-8 levels are expected for tall forest ecosystems.

Luo, H.; Loescher, H. W.; Ayres, E.; Clement, R.

2010-12-01

121

'Towers in the Tempest' Computer Animation Submission  

NASA Technical Reports Server (NTRS)

The following describes a computer animation that has been submitted to the ACM/SIGGRAPH 2008 computer graphics conference: 'Towers in the Tempest' clearly communicates recent scientific research into how hurricanes intensify. This intensification can be caused by a phenomenon called a 'hot tower.' For the first time, research meteorologists have run complex atmospheric simulations at a very fine temporal resolution of 3 minutes. Combining this simulation data with satellite observations enables detailed study of 'hot towers.' The science of 'hot towers' is described using: satellite observation data, conceptual illustrations, and a volumetric atmospheric simulation data. The movie starts by showing a 'hot tower' observed by NASA's Tropical Rainfall Measuring Mission (TRMM) spacecraft's three dimensional precipitation radar data of Hurricane Bonnie. Next, the dynamics of a hurricane and the formation of 'hot towers' are briefly explained using conceptual illustrations. Finally, volumetric cloud, wind, and vorticity data from a supercomputer simulation of Hurricane Bonnie are shown using volume techniques such as ray marching.

Shirah, Greg

2008-01-01

122

Devil's Tower Geology  

NSDL National Science Digital Library

This site from the National Park Service briefly addresses the geology of Devil's Tower. The evolution of various theories on the formation of the tower are discussed. A slide show of the emplacement of the tower is also available.

National Park Service (NPS)

123

Voltage stabilization in connection of wind farms to transmission network using VSC-HVDC  

Microsoft Academic Search

This paper investigates possible improvements of grid voltage stability in connection of 40 MW wind farm to transmission network using VSC-HVDC. The 40 MW wind farm comprises 20 individual 2 MW permanent magnet synchronous generators. The voltage at the transmission network terminal should be re-established with minimized power losses during wind speed fluctuations and after the clearance of grid side

Hanif Livani; Javad Rouhi; Hossein Karimi-Davijani

2008-01-01

124

Improvement of voltage quality in connection of wind farms to transmission network using VSC-HVDC  

Microsoft Academic Search

This paper studies possible improvements of voltage quality in connection of 40 MW wind farm to transmission network using VSC-HVDC link. The 40 MW wind farm includes 20 individual 2 MW permanent magnet synchronous generators. The voltage at the transmission network terminal should be re-established with minimized power losses during wind speed fluctuations and after the clearance of grid side

Hanif. Livani; J. Rouhi; S. Lesan; H. Karimi-Davijani

2008-01-01

125

An adaptive relaying for the protection of a wind farm interconnected with distribution networks  

Microsoft Academic Search

This paper proposes the adaptive relaying of protective devices applied in the neighboring distribution feeders for reliable and efficient operations of a wind farm interconnected with distribution networks by dedicated lines. The wind farm connected with the electric power network is one of the great alternative energy sources; however, it would be also highly possible that the wind turbine generators

S. I. Jang; J. H. Choi; J. W. Kim; D. M. Choi

2003-01-01

126

WIND: A scalable and lightweight network topology service for peer-to-peer applications  

Microsoft Academic Search

We present an Internet-scale network topology information (NTI) service named WIND for localizing P2P traffic. Central to WIND are the two simple ideas: 1) obtaining NTI directly from routing infrastructures, and 2) leveraging existing, widely deployed DNS caches for NTI delivery. WIND fulfills the fidelity, flexibility and scalability requirement of an effective NTI service. WIND is deployed in CERNET. We

Hongqiang Liu; Yongqiang Xiong; CongXiao Bao; Xing Li; Guobin Shen; Dan Li

2010-01-01

127

Neural-network-based sensorless maximum wind energy capture with compensated power coefficient  

Microsoft Academic Search

This paper describes a small wind generation system where neural network principles are applied for wind speed estimation and robust control of maximum wind power extraction against potential drift of wind turbine power coefficient curve. The new control system will deliver maximum electric power to a customer with light weight, high efficiency, and high reliability without mechanical sensors. The concept

Hui Li; K. L. Shi; P. G. McLaren

2005-01-01

128

Wind mills  

Microsoft Academic Search

A wind mill construction is disclosed, including a rigid tower structure to the upper end of which is connected for rotation about a vertical axis a wind turbine housing to which is journalled for rotation about a horizontal axis a propeller of the two-blade on three-blade type, characterized in that a strip member extends generally helically about the tower structure

Ottosen

1979-01-01

129

Cooling tower  

SciTech Connect

This patent describes a cooling tower comprising: an outer structure composed of a side wall and a top cover; the top cover having an opening on its center with a deflection device for reducing re-circulation of air within the housing; a motor which is fixed in a motor seat and whose shaft forms a spindle which rotates a rotatable cylinder; a rotatable cylinder having sides which have a plurality of small apertures, a centrifugal fan being an integral part of the rotating cylinder, the bottom portion of the cylinder engaging the shaft of the motor, the centrifugal fan comprising: a first flange on the top portion, a second flange on the portion with apertures, a plurality of blades which are equally spaced and fixed between the first and second flanges; a screen positioned concentrically around the rotatable cylinder and secured onto the inside of the top cover of the outer structure, the screen comprising a net and a frame, the frame further comprising a flange and skirt, the frame being secured onto the inside of the top cover of the outer structure with the flange, the skirt extending upwards and inwards through the bottom portion of the rotatable cylinder, the net adherent to the frame.

Liu, W.H.

1987-08-18

130

Recommendations for a wind profiling network to support Space Shuttle launches  

NASA Technical Reports Server (NTRS)

The feasibility is examined of a network of clear air radar wind profilers to forecast wind conditions before Space Shuttle launches during winter. Currently, winds are measured only in the vicinity of the shuttle launch site and wind loads on the launch vehicle are estimated using these measurements. Wind conditions upstream of the Cape are not monitored. Since large changes in the wind shear profile can be associated with weather systems moving over the Cape, it may be possible to improve wind forecasts over the launch site if wind measurements are made upstream. A radar wind profiling system is in use at the Space Shuttle launch site. This system can monitor the wind profile continuously. The existing profiler could be combined with a number of radars located upstream of the launch site. Thus, continuous wind measurements would be available upstream and at the Cape. NASA-Marshall representatives have set the requirements for radar wind profiling network. The minimum vertical resolution of the network must be set so that the wind shears over the depths greater than or = 1 km will be detected. The network should allow scientists and engineers to predict the wind profile over the Cape 6 hours before a Space Shuttle launch.

Zamora, R. J.

1992-01-01

131

Network wind power over the Pacific northwest. Appendix 1: Wind statistics summaries for the wind power data stations  

NASA Astrophysics Data System (ADS)

Tables and graphs are presented concerning monthly wind speed summaries; wind spectrum analyzer summaries; high wind speed summaries; and six hourly speed and direction plots for selected wind power sites. Wind flow plots in the Goodnoe Hills MOD-2 wind turbine area and wind flow plots in the Goodnoe Hills and Juniper Point area are included.

Baker, R. W.; Hewson, E. W.

1980-10-01

132

Large Amplitude Spatial and Temporal Gradients in Atmospheric Boundary Layer CO2 Mole Fractions Detected With a Tower-Based Network in the U.S. Upper Midwest  

SciTech Connect

This study presents observations of atmospheric CO{sub 2} mole fraction from a nine-tower, regional network deployed during the North American Carbon Program's Mid-Continent Intensive during 2007-2009. Within this network in a largely agricultural area, mean atmospheric CO{sub 2} gradients were strongly correlated with both ground-based inventory data and estimates from satellite remote sensing. The average seasonal drawdown for corn-dominated sites (35 ppm) is significantly larger than has been observed at other continental boundary layer sites. Observed growing-season median CO{sub 2} gradients are strongly dependent on local flux. The gradients between cross-vegetation site-pairs, for example, average 2.0 ppm/100 km, four times larger than the similar-vegetation site-pair average. Daily-timescale gradients are as large as 5.5 ppm/100 km, but dominated by advection rather than local flux. Flooding in 2008 led to a region-wide 23 week delay in growing-season minima. The observations show that regional-scale CO{sub 2} mole fraction networks yield large, coherent signals governed largely by regional sources and sinks of CO{sub 2}.

Miles, Natasha; Richardson, S. J.; Davis, Kenneth J.; Lauvaux, Thomas; Andrews, A.; West, Tristram O.; Bandaru, Varaprasad; Crosson, Eric R.

2012-02-21

133

The natural frequencies of coupled in-line towers  

NASA Astrophysics Data System (ADS)

There are many tall, slender fractionating towers and distilling towers in oil refineries and chemical plants. Frequently, several towers are arranged in a line; they may also be coupled structurally by platforms at various levels. The designer must take steps to assure that damage due to wind loads, seismic loads, or wind-induced vibration cannot occur. The natural frequencies of the coupled towers, especially the lowest frequency, are the most important parameters for dynamic analyses. This is the problem addressed here. The results obtained from a newly developed analytical procedure are compared with measurements in the field, and are in good agreement.

Nie, Q.; Nieh, C. D.; Cai, J.; Zhang, M.

1989-10-01

134

PSCAD based simulation of the connection of a wind generator to the network  

Microsoft Academic Search

The simulation of the behavior of an induction generator during the connection of a wind turbine by means of a soft starter is presented. The problems concerning the connection of a wind turbine to the network appear more evident when the wind turbine operates alone feeding local loads in weak systems. The reactive power depends significantly on the derivative of

A. G. Gonzalez Rodriguez; M. Burgos Paydn; C. Izquierdo Mitchell

2001-01-01

135

An Artificial Neural Network Approach for Short-Term Wind Power Forecasting in Portugal  

Microsoft Academic Search

This paper presents an artificial neural network approach for short-term wind power forecasting in Portugal. The increased integration of wind power into the electric grid, as nowadays occurs in Portugal, poses new challenges due to its intermittency and volatility. Hence, good forecasting tools play a key role in tackling these challenges. The accuracy of the wind power forecasting attained with

J. P. S. Catalao; H. M. I. Pousinho; V. M. F. Mendes

2009-01-01

136

Tall Tower Challenge  

NSDL National Science Digital Library

In this activity, learners explore the design of tall structures such as skyscrapers and telecommunication towers. Learners work in teams to engineer the tallest tower they can build using just straws, pipe cleaners, and paperclips. The tower must be strong enough to support the weight of a golf ball for two minutes.

Ieee

2014-05-22

137

Vortex-augmented cooling tower-windmill combination  

DOEpatents

A cooling tower for cooling large quantities of effluent water from a production facility by utilizing natural wind forces includes the use of a series of helically directed air inlet passages extending outwardly from the base of the tower to introduce air from any direction in a swirling vortical pattern while the force of the draft created in the tower makes it possible to place conventional power generating windmills in the air passages to provide power as a by-product.

McAllister, Jr., John E. (Aiken, SC)

1985-01-01

138

Vortex-augmented cooling tower-windmill combination  

SciTech Connect

A cooling tower for cooling large quantities of effluent water from a production facility by utilizing natural wind forces includes the use of a series of helically directed air inlet passages extending outwardly from the base of the tower to introduce air from any direction in a swirling vortical pattern while the force of the draft created in the tower makes it possible to place conventional power generating windmills in the air passages to provide power as a by-product.

McAllister Jr., J. E.

1985-02-12

139

Plant Vogtle cooling tower studies  

SciTech Connect

Intensive ground-based field studies of plumes from two large, natural-draft cooling towers were conducted in support of the MTI modeling effort. Panchromatic imagery, IR imagery, meteorological data, internal tower temperatures and plant power data were collected during the field studies. These data were used to evaluate plume simulations, plume radioactive transfer calculations and plume volume estimation algorithms used for power estimation. Results from six field studies indicate that a 3-D atmospheric model at sufficient spatial resolution can effectively simulate a cooling tower plume if the plume is of sufficient size and the ambient meteorology is known and steady. Small plumes and gusty wind conditions degrade the agreement between the simulated and observed plumes. Thermal radiance calculations based on the simulated plumes produced maximum IR temperatures (near tower exit) which were in good agreement with measured IR temperatures for the larger plumes. For the smaller plumes, the calculated IR temperature was lower than the measured temperature by several degrees. Variations in maximum IR plume temperature with decreasing power (one reactor was undergoing a shutdown process), were clearly observed in the IR imagery and seen in the simulations. These temperature changes agreed with those calculated from an overall tower energy and momentum balance. Plume volume estimates based on camcorder images at three look angles were typically 20--30 percent larger than the plume volumes derived from the simulations, although one estimate was twice the simulated volume. Volume overestimation is expected and will have to be accounted for to some degree if plume volume is to be a useful diagnostic quantity in power estimation. Volume estimation with MTI imagery will require a large, stable plume and two looks in the visible bands (5m GSD) along with a solar shadow.

O'Steen, L.

2000-01-26

140

A neural network based wake model for small wind turbine siting near obstacles  

NASA Astrophysics Data System (ADS)

Many potential small wind turbine locations are near obstacles such as buildings and shelterbelts, which can have a significant, detrimental effect on the local wind climate. This thesis describes the creation of a new model which can predict the wind speed, turbulence intensity, and wind power density at any point in an obstacle's region of influence, relative to unsheltered conditions. Artificial neural networks were used to learn the relationship between an obstacle's characteristics and its effects on the local wind. The neural network was trained using measurements collected in the wakes of scale models exposed to a simulated atmospheric boundary layer in a wind tunnel. A field experiment was conducted to validate the wind tunnel measurements. Model predictions are most accurate in the far wake region. The estimated mean uncertainties associated with model predictions of velocity deficit, power density deficit, and turbulence intensity excess are 5.0%, 15%, and 12.8%, respectively.

Brunskill, Andrew William

141

Approaching hybrid wind-diesel systems and controller area network  

Microsoft Academic Search

High wind penetration hybrid wind-diesel systems have complex control requirements. The random nature of the wind, the cubic velocity to power relationship and the fast response of wind turbines make control goals like maintain system stability, and prescribed power quality levels, not easy to achieve. This paper deals with how to implement a distributed control system based on the controller

R. Sebastian; M. Castro; E. Sancristobal; F. Yeves; J. Peire; J. Quesada

2002-01-01

142

WindTalker: A P2P-Based Low-Latency Anonymous Communication Network  

NASA Astrophysics Data System (ADS)

Compared with traditional static anonymous communication networks, the P2P architecture can provide higher anonymity in communication. However, the P2P architecture also leads to more challenges, such as route, stability, trust and so on. In this paper, we present WindTalker, a P2P-based low-latency anonymous communication network. It is a pure decentralized mix network and can provide low-latency services which help users hide their real identity in communication. In order to ensure stability and reliability, WindTalker imports “seed nodes” to help a peer join in the P2P network and the peer nodes can use gossip-based protocol to exchange active information. Moreover, WindTalker uses layer encryption to ensure the information of relayed messages cannot be leaked. In addition, malicious nodes in the network are the major threat to anonymity of P2P anonymous communication, so WindTalker imports a trust mechanism which can help the P2P network exclude malicious nodes and optimize the strategy of peer discovery, tunnel construction, and relaying etc. in anonymous communications. We deploy peer nodes of WindTalker in our campus network to test reliability and analyze anonymity in theory. The network measurement and simulation analysis shows that WindTalker can provide low-latency and reliable anonymous communication services.

Zhang, Jia; Duan, Haixin; Liu, Wu; Wu, Jianping

143

Development of a Nonlinear Soft-Sensor Using a GMDH Network for a Refinery Crude Distillation Tower  

NASA Astrophysics Data System (ADS)

In atmospheric distillation processes, the stabilization of processes is required in order to optimize the crude-oil composition that corresponds to product market conditions. However, the process control systems sometimes fall into unstable states in the case where unexpected disturbances are introduced, and these unusual phenomena have had an undesirable affect on certain products. Furthermore, a useful chemical engineering model has not yet been established for these phenomena. This remains a serious problem in the atmospheric distillation process. This paper describes a new modeling scheme to predict unusual phenomena in the atmospheric distillation process using the GMDH (Group Method of Data Handling) network which is one type of network model. According to the GMDH network, the model structure can be determined systematically. However, the least squares method has been commonly utilized in determining weight coefficients (model parameters). Estimation accuracy is not entirely expected, because the sum of squared errors between the measured values and estimates is evaluated. Therefore, instead of evaluating the sum of squared errors, the sum of absolute value of errors is introduced and the Levenberg-Marquardt method is employed in order to determine model parameters. The effectiveness of the proposed method is evaluated by the foaming prediction in the crude oil switching operation in the atmospheric distillation process.

Fujii, Kenzo; Yamamoto, Toru

144

Neural network based control of Doubly Fed Induction Generator in wind power generation  

NASA Astrophysics Data System (ADS)

To complement the other types of pollution-free generation wind energy is a viable option. Previously wind turbines were operated at constant speed. The evolution of technology related to wind systems industry leaded to the development of a generation of variable speed wind turbines that present many advantages compared to the fixed speed wind turbines. In this paper the phasor model of DFIG is used. This paper presents a study of a doubly fed induction generator driven by a wind turbine connected to the grid, and controlled by artificial neural network ANN controller. The behaviour of the system is shown with PI control, and then as controlled by ANN. The effectiveness of the artificial neural network controller is compared to that of a PI controller. The SIMULINK/MATLAB simulation for Doubly Fed Induction Generator and corresponding results and waveforms are displayed.

Barbade, Swati A.; Kasliwal, Prabha

2012-07-01

145

Application of Fuzzy Neural Network Sliding Mode Controller for Wind Driven Induction Generator System  

Microsoft Academic Search

An induction generator (IG) speed drive with the application of a sliding mode controller and a proposed fuzzy neural network (FNN) controller is introduced in this paper. Grid connected wind energy conversion system (WECS) present interesting control demands, due to the intrinsic nonlinear characteristic of wind mills and electric generators. The FNN torque compensation is feedforward to increase the robustness

Chih-Ming Hong; Whei-Min Lin; Fu-Sheng Cheng

2007-01-01

146

TORQUE RIPPLE MINIMIZATION IN DOUBLY FED INDUCTION MACHINE USED IN WIND MILLS WITH ARTIFICIAL NEURAL NETWORK  

Microsoft Academic Search

This paper discusses an Artificial Neural Network (ANN) based method for reducing the torque ripple in a Doubly Fed Induction machine (DFIM) in which Direct Torque Control (DTC) scheme is applied. DFIM is gaining popularity as the best alternative for wind energy generation system. Often, wind energy generation demands good torque dynamic performance. ANN is used here to give pulses

GEETHA RAMADAS; T. THYAGARAJAN; VEDAM SUBRSHMANYAM

2009-01-01

147

Short-term wind power forecasting in Portugal by neural networks and wavelet transform  

Microsoft Academic Search

This paper proposes artificial neural networks in combination with wavelet transform for short-term wind power forecasting in Portugal. The increased integration of wind power into the electric grid, as nowadays occurs in Portugal, poses new challenges due to its intermittency and volatility. Hence, good forecasting tools play a key role in tackling these challenges. Results from a real-world case study

J. P. S. Catalão; H. M. I. Pousinho; V. M. F. Mendes

2011-01-01

148

Control of DFIG-based wind farms for power network frequency support  

Microsoft Academic Search

This paper investigates the frequency control scheme of a doubly fed induction generator (DFIG)-based wind farms to provide frequency support for the power system steady operation. Due to the decoupling of the rotor speed and the grid frequency by the connected converters, the DFIG-based wind farm rarely contributes to the network effective inertia. This is particularly true in the small

Xiangyu Zhang; Heming Li; Yi Wang

2010-01-01

149

Wind Turbine Farm Network Grounding Design Using Integrated Simulation Methods and Techniques  

Microsoft Academic Search

The design of a wind farm grounding system including the substation and wind turbine generators of the collector network is a very comprehensive task. Powerful integrated grounding simulation methods and design techniques that are appropriate for carrying out this kind of work are presented and discussed in this paper. They include soil structure model selection based on in-situ soil resistivity

J. Liu; F. P. Dawalibi

2010-01-01

150

Neural networks for condition monitoring of wind turbines  

Microsoft Academic Search

Wind energy is the renewable energy source considered a hope in future as a clean and sustainable energy, as can be seen by the growing number of wind farms all over the world. With the huge proliferation of wind farms, as an alternative to the traditional fossil power generation, the economic issues dictate the necessity of monitoring systems to optimize

R. F. Mesquita Brandao; J. A. Beleza Carvalho; F. P. Maciel Barbosa

2010-01-01

151

GOne with the Wind ON_Mars (GOWON): A Wind-Driven Networked System of Mobile Sensors on Mars  

NASA Astrophysics Data System (ADS)

A revolutionary way of studying the surface of Mars using a wind-driven network of mobile sensors. GOWON could achieve NASA's scientific objectives on Mars in a cost-effective way, leaving a long lasting sensing and searching infrastructure on Mars.

Davoodi, F.; Hajimiri, A.; Murphy, N.; Nikzad, S. H.; Nesnas, I.; Mischna, M.; Nesmith, B.

2012-06-01

152

Optimal Electric Network Design for a Large Offshore Wind Farm Based on a Modified Genetic Algorithm Approach  

Microsoft Academic Search

The increasing development of large-scale offshore wind farms around the world has caused many new technical and economic challenges to emerge. The capital cost of the electrical network that supports a large offshore wind farm constitutes a significant proportion of the total cost of the wind farm. Thus, finding the optimal design of this electrical network is an important task,

Francisco M. Gonzalez-Longatt; Peter Wall; Pawel Regulski; Vladimir Terzija

2012-01-01

153

Investigation of power loss and voltage stability limits for large wind farm connections to a subtransmission network  

Microsoft Academic Search

Today wind farms are growing both in size and in number. Being connected at higher voltage levels, their impacts are becoming more widespread. High demand for reactive power is known as one major characteristic of large wind farms that causes voltage problems to power networks. The larger the wind farm, the more severe this effect could be. If the network

L. T. Ha; T. K. Saha

2004-01-01

154

Airport Remote Tower Sensor Systems  

NASA Technical Reports Server (NTRS)

Networks of video cameras, meteorological sensors, and ancillary electronic equipment are under development in collaboration among NASA Ames Research Center, the Federal Aviation Administration (FAA), and the National Oceanic Atmospheric Administration (NOAA). These networks are to be established at and near airports to provide real-time information on local weather conditions that affect aircraft approaches and landings. The prototype network is an airport-approach-zone camera system (AAZCS), which has been deployed at San Francisco International Airport (SFO) and San Carlos Airport (SQL). The AAZCS includes remotely controlled color video cameras located on top of SFO and SQL air-traffic control towers. The cameras are controlled by the NOAA Center Weather Service Unit located at the Oakland Air Route Traffic Control Center and are accessible via a secure Web site. The AAZCS cameras can be zoomed and can be panned and tilted to cover a field of view 220 wide. The NOAA observer can see the sky condition as it is changing, thereby making possible a real-time evaluation of the conditions along the approach zones of SFO and SQL. The next-generation network, denoted a remote tower sensor system (RTSS), will soon be deployed at the Half Moon Bay Airport and a version of it will eventually be deployed at Los Angeles International Airport. In addition to remote control of video cameras via secure Web links, the RTSS offers realtime weather observations, remote sensing, portability, and a capability for deployment at remote and uninhabited sites. The RTSS can be used at airports that lack control towers, as well as at major airport hubs, to provide synthetic augmentation of vision for both local and remote operations under what would otherwise be conditions of low or even zero visibility.

Maluf, David A.; Gawdiak, Yuri; Leidichj, Christopher; Papasin, Richard; Tran, Peter B.; Bass, Kevin

2006-01-01

155

Cooling tower waste reduction  

Microsoft Academic Search

At Lawrence Livermore National Laboratory (LLNL), the two main cooling tower systems (central and northwest) were upgraded during the summer of 1997 to reduce the generation of hazardous waste. In 1996, these two tower systems generated approximately 135,400 lbs (61,400 kg) of hazardous sludge, which is more than 90 percent of the hazardous waste for the site annually. At both,

S. J. Coleman; J. Celeste; R. Chine; C. Scott

1998-01-01

156

Super Golf Tower  

NSDL National Science Digital Library

In this engineering activity, challenge learners to build a tower out of 10 sheets of newspaper and 3 feet of masking tape, which can hold a golf ball balancing at the top. Learners explore ways to strengthen the paper tower as well as stabilize it to hold the ball.

Boston, Wgbh

2002-01-01

157

Leaning Tower of PESA  

ERIC Educational Resources Information Center

There is a certain similarity between the Philosophy of Education Society of Australasia (PESA) and the leaning tower of Pisa. Both have a certain presence on the landscape: the tower has a commanding appearance on the Italian countryside while PESA has left its mark on the academic fabric of Australasia. Both are much loved: Pisa by visiting…

Clark, John

2009-01-01

158

Confusion at the Tower  

ERIC Educational Resources Information Center

This study will explore the omission of the Tower of Babel narrative from middle and secondary school world history, world studies, and world geography textbooks and will consider what might be learned from inclusion of the story in the curriculum. A total of 17 textbooks are analyzed. The Tower of Babel narrative is examined within the context of…

Li, Loretta F.

2014-01-01

159

Visibility Graphs of Towers  

Microsoft Academic Search

A tower is a polygon consisting of two reflex chains sharing one common endpoint, together with one edge joining the other endpoints of the chains. A linear time algorithm is given to recognize the [vertex] visibility graphs of towers, and these graphs are characterized as bipartite permutation graphs with an added Hamiltonian cycle. Similar results have been obtained independently by

Paul Colley; Anna Lubiw; Jeremy Spinrad

1997-01-01

160

Statue Display Tower  

NSDL National Science Digital Library

In this activity, learners design, build, test and redesign a display tower that will meet a specific set of criteria and constraints. Learners apply the engineering design process to solve the Golden Book design challenge to make a low cost display tower that can hold a statue and can be taken apart and reassembled easily for transporting from one library to another.

Ieee

2013-07-08

161

Wind turbine  

SciTech Connect

The improvement in a wind turbine comprises providing a tower with a freely liftable mount and adapting a nacelle which is fitted with a propeller windwheel consisting of a plurality of rotor blades and provided therein with means for conversion of wind energy to be shifted onto said mount attached to the tower. In case of a violent wind storm, the nacelle can be lowered down to the ground to protect the rotor blades from breakage due to the force of the wind. Required maintenance and inspection of the nacelle and replacement of rotor blades can be safely carried out on the ground.

Abe, M.

1982-01-19

162

Turbojet modeling in wind milling based on neural network incorporating priori knowledge  

Microsoft Academic Search

Neural network is an effective method for turbojet modeling in wind milling, but its deficiency in generalization ability has restricted its application in engineering. Nonlinear PCA (principal component analysis), although is very effective in decreasing the dimensions of input variable and subsequently improving neural network's generalization ability, it has difficulty in finding an appropriate nonlinear transform in engineering application. A

Yu Daren; Wu Zhiwen

2003-01-01

163

Short term wind speed forecasting in La Venta, Oaxaca, México, using artificial neural networks  

Microsoft Academic Search

In this paper the short term wind speed forecasting in the region of La Venta, Oaxaca, Mexico, applying the technique of artificial neural network (ANN) to the hourly time series representative of the site is presented. The data were collected by the Comisión Federal de Electricidad (CFE) during 7 years through a network of measurement stations located in the place

Erasmo Cadenas; Wilfrido Rivera

2009-01-01

164

Control of large wind turbine generators connected to utility networks  

NASA Technical Reports Server (NTRS)

This is an investigation of the control requirements for variable pitch wind turbine generators connected to electric power systems. The requirements include operation in very small as well as very large power systems. Control systems are developed for wind turbines with synchronous, induction, and doubly fed generators. Simulation results are presented. It is shown how wind turbines and power system controls can be integrated. A clear distinction is made between fast control of turbine torque, which is a peculiarity of wind turbines, and slow control of electric power, which is a traditional power system requirement.

Hinrichsen, E. N.

1983-01-01

165

Neural Network Based Interpolation of Wind Tunnel Test Data  

Microsoft Academic Search

The main objective of this research is to design a generalized framework for knowledge based management system (KBMS). This proposed system captures the knowledge of experts and the knowledge acquired is used for designing new systems. Wind Tunnel Test data of missiles has been taken into consideration for knowledge management in this research work and the interpolation of wind tunnel

S. Thamarai Selvi; S. Rama; E. Mahendran

2007-01-01

166

Tower Camera Handbook  

SciTech Connect

The tower camera in Barrow provides hourly images of ground surrounding the tower. These images may be used to determine fractional snow cover as winter arrives, for comparison with the albedo that can be calculated from downward-looking radiometers, as well as some indication of present weather. Similarly, during spring time, the camera images show the changes in the ground albedo as the snow melts. The tower images are saved in hourly intervals. In addition, two other cameras, the skydeck camera in Barrow and the piling camera in Atqasuk, show the current conditions at those sites.

Moudry, D

2005-01-01

167

Surface and Tower Meteorological Instrumentation at Atqasuk (METTWR2H) Handbook  

SciTech Connect

The Atqasuk meteorology station (AMET) uses mainly conventional in situ sensors to measure wind speed, wind direction, air temperature, dew point, and humidity mounted on a 10-m tower. It also obtains barometric pressure, visibility and precipitation data from sensors at or near the base of the tower. In addition, a chilled mirror hygrometer (CMH) is located at 1 m for comparison purposes. Temperature and relative humidity (RH) probes are mounted at 2 m and 5 m on the tower.

Ritsche, MT

2006-01-01

168

Aquarius: Tower Rollback  

NASA Video Gallery

The mobile service tower at NASA's Launch Complex-2 at Vandenberg Air Force Base in California is being moved away from the ULA Delta II rocket with the Aquarius/SAC-D spacecraft atop, in preparati...

169

The Tower Challenge  

NSDL National Science Digital Library

This activity is an exciting and highly interactive opportunity for students to exercise their creativity and design skills. Working in cooperative groups, students are challenged to explore the geometry of tower design and construction, first by experime

Eichinger, John

2009-05-30

170

Tower O' Power  

NSDL National Science Digital Library

In this activity, students learn about creating a design directly from a CAD (computer-aided design) program. They will design a tower in CAD and manufacture the parts with a laser cutter. A competition determines the tower design with the best strength:weight ratio. Students also investigate basic structural truss concepts and stress concentrations. Partnership with a local college or manufacturing center is necessary for the completion of this project.

Integrated Teaching And Learning Program

171

Application of Radial Basis Function Networks for Wind Power Forecasting  

Microsoft Academic Search

In this paper, an advanced system based on artificial intelligence and fuzzy logic techniques is developed to predict the\\u000a wind power output of a wind farm. A fuzzy logic model is applied first to check the reliability of the numerical weather predictions\\u000a (NWPs) and to split them in two sub-sets, of good and bad quality NWPs, respectively. Two Radial Basis

George Sideratos; Nikos D. Hatziargyriou

2006-01-01

172

Lewis Research Center studies of multiple large wind turbine generators on a utility network  

NASA Technical Reports Server (NTRS)

A NASA-Lewis program to study the anticipated performance of a wind turbine generator farm on an electric utility network is surveyed. The paper describes the approach of the Lewis Wind Energy Project Office to developing analysis capabilities in the area of wind turbine generator-utility network computer simulations. Attention is given to areas such as, the Lewis Purdue hybrid simulation, an independent stability study, DOE multiunit plant study, and the WEST simulator. Also covered are the Lewis mod-2 simulation including analog simulation of a two wind turbine system and comparison with Boeing simulation results, and gust response of a two machine model. Finally future work to be done is noted and it is concluded that the study shows little interaction between the generators and between the generators and the bus.

Gilbert, L. J.; Triezenberg, D. M.

1979-01-01

173

Hurricane Frances Rain Towers  

NSDL National Science Digital Library

NASAs TRMM spacecraft allows us to look under Hurricane Frances clouds to see the rain structure. Spikes in the rain structure known as "Hot Towers" indicate storm intensity. The "hot towers" which refers to the tall cumulonimbus, has been seen as one of the mechanisms by which the intensity of a tropical cyclone is maintained. Because of the size (1-5 km) and short duration (30 minute to 2 hours) of these hot towers, studies of these events have been limited to descriptive studies from aircraft observations, although a few have attempted to use the presence of hot towers in a predictive capacity. Before TRMM, no data set exists that can show globally and definitively the presence of these hot towers in cyclone systems. Aircraft radar studies of individual storms lack global coverage. Global microwave or Infrared sensor observations do not provide the needed spatial resolution. With a ground resolution of 5 km, the TRMM Precipitation Radar provided the needed data set for examining the predictive value of hot towers in cyclone intensification.

Perkins, Lori; Halverson, Jeff

2005-04-11

174

Simulation studies of multiple large wind turbine generators on a utility network  

NASA Technical Reports Server (NTRS)

The potential electrical problems that may be inherent in the inertia of clusters of wind turbine generators and an electric utility network were investigated. Preliminary and limited results of an analog simulation of two MOD-2 wind generators tied to an infinite bus indicate little interaction between the generators and between the generators and the bus. The system demonstrated transient stability for the conditions considered.

Gilbert, L. J.; Triezenberg, D. M.

1979-01-01

175

Detail of wire ground screen in relation to towers, looking ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail of wire ground screen in relation to towers, looking southeast - Over-the-Horizon Backscatter Radar Network, Tulelake Radar Site Receive Sector Five Antenna Array, Unnamed Road West of Double Head Road, Tulelake, Siskiyou County, CA

176

Characterizing the Vertical Flux of CO2 within the Nocturnal Boundary Layer near a Tall Tower  

NASA Astrophysics Data System (ADS)

Understanding the vertical dispersion of carbon dioxide respired from plants at night is crucial to distinguishing local- to regional-scale transport and continental-scale transport in global carbon budgets. When atmospheric conditions are stable, CO2 will be weakly mixed, and nearby detectors above the surface layer will instead sample CO2 carried from large distances. These conditions often prevail during the nighttime, making that period ideal for continental-scale sampling. On the other hand, during periods of moderate or intermittent nocturnal turbulence, locally-respired CO2 will be transported through the surface layer and produce a signal at the detector. In August 2008, a 329m tall TV tower (33.4058N, 81.834W) in Aiken, South Carolina (the "South Carolina Tower" http://www.esrl.noaa.gov/gmd/ccgg/towers/#sct) was incorporated into the NOAA-Global Monitoring Division's Tall Tower network. This site is located within a region that varies from agricultural, broken forests, suburban, urban and industrial. Emissions from several cities (most notably Augusta, GA) and industrial sites are within 50km of the tower and may contribute disproportionately to the nighttime tower readings. To distinguish local and regional sources, it is necessary to characterize vertical turbulent transport at this site. There are several ways to do this, and we focus on three. First, a mesoscale model was run at high-resolution to recreate the winds and temperature observed during a May 2009 nocturnal tracer release field project conducted in the region surrounding the site. The model data then served as input to a Lagrangian transport model. This was done for two eight-hour periods on successive but different nights: one slightly stable, and the other more stable. The coupled mesoscale/transport model was then validated against the tracer data, and was used to calculate the dispersion properties of the tracer and provide a 3-dimensional picture of the plume. For comparison, we apply two other methods to calculate eddy diffusivity. We calculate it directly using sonic anemometer and fast-response CO2 flux and concentration data from the tall tower. The fast response data (10Hz) allows for the explicit calculation of the turbulent transport and, along with the vertical gradient, provide an estimate of the diffusivity. As a third method, the eddy diffusivity can also be calculated by an empirical method that uses as input the turbulent properties measured at the tower. We select one such method and compare the results to the other two estimates.

Werth, D. W.; Buckley, R.; Kurzeja, R.; Zhang, G.; Parker, M.; Duarte, H.; Leclerc, M.

2012-12-01

177

Short-term wind generation forecasting and confidence interval estimation based on neural networks trained by extended Kalman particle filter  

Microsoft Academic Search

Short-term wind generation forecasting predicts wind power 24-hours into the future in hourly steps. Effective forecasting is important for reliability, electricity markets and transmission grids. It is however difficult in view of the intermittent nature of the wind generation. We previously presented a method of neural networks trained by extended Kalman filter. In this paper, the method of the neural

Che Guan; Peter B. Luh; Wen Cao

2011-01-01

178

Wind shear forecasting by Chaotic Oscillatory-based Neural Networks (CONN) with Lee Oscillator (retrograde signalling) model  

Microsoft Academic Search

Wind shear is a conventionally unpredictable meteorological phenomenon which presents a common danger to aircraft, particularly on takeoff and landing at airports. This paper describes a method for forecasting wind shear using an advanced paradigm from computational intelligence, chaotic oscillatory-based neural networks (CONN). The method uses weather data to predict wind velocities and directions over a short time period. This

Max H. Y. Wong; Raymond S. T. Lee; James Nga-kwok Liu

2008-01-01

179

Radial Basis Function Networks for Wind Speed Prediction  

Microsoft Academic Search

The introduction of a large quantity of wind generators on the Portuguese electric grid, will produce the effect of having a large percentage of installed power whose production is not controllable. The consequence is a major difficulty to the grid operator in dealing with power availability and oscillations in the frequency. There is the urgent need of a reliable tool

GONÇALO XUFRE SILVA; P. M. FONTE; J. C. QUADRADO

2006-01-01

180

ARIMA vs. Neural networks for wind speed forecasting  

Microsoft Academic Search

In this paper an ARIMA model is used for time-series forecast involving wind speed measurements. Results are compared with the performance of a back propagation type NNT. Results show that ARIMA model is better than NNT for short time-intervals to forecast (10 minutes, 1 hour, 2 hours and 4 hours). Data was acquired from a unit located in Southern Andalusia

J. C. Palomares-Salas; J. G. Ramiro; J. Melgar; A. Aguera; A. Moreno

2009-01-01

181

Meteorological Monitoring And Warning Computer Network  

NASA Technical Reports Server (NTRS)

Meteorological monitoring system (MMS) computer network tracks weather conditions and issues warnings when weather hazards are about to occur. Receives data from such meteorological instruments as wind sensors on towers and lightning detectors, and compares data with weather restrictions specified for outdoor activities. If weather violates restriction, network generates audible and visible alarms to alert people involved in activity. Also displays weather and toxic diffusion data and disseminates weather forecasts, advisories, and warnings to workstations.

Evans, Randolph J.; Dianic, Allan V.; Moore, Lien N.

1996-01-01

182

Winding Numbers and Average Frequencies in Phase Oscillator Networks  

Microsoft Academic Search

We study networks of coupled phase oscillators and show that\\u000a network architecture can force relations between average\\u000a frequencies of the oscillators. The main tool of our analysis is\\u000a the coupled cell theory developed by Stewart, Golubitsky, Pivato,\\u000a and Torok, which provides precise relations between network\\u000a architecture and the corresponding class of ODEs in RM and\\u000a gives conditions for the flow-invariance

M. Golubitsky; K. Josic; E. Shea-Brown

2006-01-01

183

Solar power towers  

SciTech Connect

The high desert near Barstow, California, has witnessed the development of this country`s first two solar power towers. Solar One operated successfully from 1982 to 1988 and proved that power towers work efficiently to produce utility-scale power from sunlight. Solar Two was connected to the utility grid in 1996 and is operating today. Like its predecessor, Solar Two is rated at 10 megawatts. An upgrade of the Solar One plant, Solar Two demonstrates how solar energy can be stored in the form of heat in molten salt for power generation on demand. The experience gained with these two pilot power towers has established a foundation on which industry can develop its first commercial plants. These systems produce electricity on a large scale. They are unique among solar technologies because they can store energy efficiently and cost effectively. They can operate whenever the customer needs power, even after dark or during cloudy weather.

Not Available

1998-04-01

184

Analysis of a utility-interactive wind-photovoltaic hybrid system with battery storage using neural network  

Microsoft Academic Search

This dissertation investigates the application of neural network theory to the analysis of a 4-kW Utility-interactive Wind-Photovoltaic System (WPS) with battery storage. The hybrid system comprises a 2.5-kW photovoltaic generator and a 1.5-kW wind turbine. The wind power generator produces power at variable speed and variable frequency (VSVF). The wind energy is converted into dc power by a controlled, tree-phase,

Francois Giraud

1999-01-01

185

8. GENERAL VIEW OF TOWER 32, LEFT, AND TOWER 31, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. GENERAL VIEW OF TOWER 32, LEFT, AND TOWER 31, RIGHT. VIEW LOOKING NORTH SHOWING AERIAL WIRE DESIGN WITH VERTICAL 'TOP HAT' WIRES IN CENTER. - Chollas Heights Naval Radio Transmitting Facility, 6410 Zero Road, San Diego, San Diego County, CA

186

Improved Direct Power Control of a DFIG-Based Wind Turbine During Network Unbalance  

Microsoft Academic Search

This paper proposes an improved coordinate direct power control (DPC) strategy for the doubly fed induction generator (DFIG) and the grid side converter (GSC) of a wind power generation system under unbalanced network conditions. Two improved DPC schemes for the DFIG and the GSC are presented, respectively. The DPC for DFIG is to eliminate the torque and stator reactive power

Peng Zhou; Yikang He; Dan Sun

2009-01-01

187

Neural network controller for a permanent magnet generator applied in a wind energy conversion system  

Microsoft Academic Search

In this paper a neural network controller for achieving maximum power tracking as well as output voltage regulation, for a wind energy conversion system (WECS) employing a permanent magnet synchronous generator, is proposed. The permanent magnet generator (PMG) supplies a DC load via a bridge rectifier and two buck–boost converters. Adjusting the switching frequency of the first buck–boost converter achieves

Mona N. Eskander

2002-01-01

188

Higher Order Wavelet Neural Networks with Kalman learning for wind speed forecasting  

Microsoft Academic Search

In this paper, a Higher Order Wavelet Neural Net- work (HOWNN) trained with an Extended Kalman Filter (EKF) is implemented to solve the wind forecasting problem. The Neural Network based scheme is composed of high order terms in the input layer, two hidden layers, one incorporating radial wavelets as activation functions and the other using classical logistic sigmoid, and an

Luis J. Ricalde; Glendy A. Catzin; Alma Y. Alanis; Edgar N. Sanchez

2011-01-01

189

Dynamic Modeling and Control of DFIG-Based Wind Turbines Under Unbalanced Network Conditions  

Microsoft Academic Search

This paper presents an analysis and control design of a doubly-fed induction generator (DFIG)-based wind generation system operating under unbalanced network conditions. A DFIG system model in the positive and negative synchronous reference frames is presented. Variations of stator active and reactive powers and generator torque are fully defined in the presence of negative sequence voltage and current. Alternative DFIG

Lie Xu; Yi Wang

2007-01-01

190

Synchronization of the DOE/NASA 100-kilowatt wind turbine generator with a large utility network  

NASA Technical Reports Server (NTRS)

The DOE/NASA 100 kilowatt wind turbine generator system was synchronized with a large utility network. The system equipments and procedures associated with the synchronization process were described. Time history traces of typical synchronizations were presented indicating that power and current transients resulting from the synchronizing procedure are limited to acceptable magnitudes.

Gilbert, L. J.

1977-01-01

191

Impact of embedded wind farms on voltage control and losses of distribution networks  

Microsoft Academic Search

Voltage magnitude of a distribution system is usually controlled using an on-load tap changer transformer with AVC relay. However, the trend of integrating embedded generation such as wind farms into distribution networks makes it difficult for the AVC relay to maintain voltage magnitude within the statutory limits, particularly if the generator is connected at a long distance from the substation

S. K. Salman; F. Jiang

1999-01-01

192

Direct adaptive control of wind energy conversion systems using Gaussian networks  

Microsoft Academic Search

Grid connected wind energy conversion systems (WECS) present interesting control demands, due to the intrinsic nonlinear characteristics of windmills and electric generators. In this paper a direct adaptive control strategy for WECS control is proposed. It is based on the combination of two control actions: a radial basis function network-based adaptive controller, which drives the tracking error to zero with

Miguel Angel Mayosky; Gustavo I. E. Cancelo

1999-01-01

193

76 FR 10328 - Grant of Authority for Subzone Status; Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs...  

Federal Register 2010, 2011, 2012, 2013

...Vestas Nacelles America, Inc. (Wind Turbine Nacelles, Hubs, Blades and Towers...special-purpose subzone at the wind turbine nacelle, hub, blade and tower...manufacturing and warehousing of wind turbine nacelles, hubs, blades and...

2011-02-24

194

Surface and Tower Meteorological Instrumentation at Barrow (METTWR4H) Handbook  

SciTech Connect

The Barrow meteorology station (BMET) uses mainly conventional in situ sensors mounted at four different heights (2m, 10m, 20m and 40m) on a 40 m tower to obtain profiles of wind speed, wind direction, air temperature, dew point and humidity. It also obtains barometric pressure, visibility and precipitation data from sensors at the base of the tower. Additionally, a Chilled Mirror Hygrometer and an Ultrasonic wind speed sensor are located near the 2m level for comparison purposes.

Ritsche, MT

2008-04-01

195

Impact of assimilating met-tower, turbine nacelle anemometer and other intensified wind farm observation systems on 0 - 12h wind energy prediction using the NCAR WRF-RTFDDA model  

Microsoft Academic Search

In collaboration with Xcel Energy and Vasaila Inc., the National Center for Atmospheric Research (NCAR) conducts modeling study to evaluate the existing and the enhanced intensive observation systems for wind power nowcasting and short-range forecasting at a northern Colorado wind farm. The NCAR WRF (Weather Research and Forecasting model) based Real-Time Four-Dimensional Data Assimilation (RTFDDA) and forecasting system, which has

Y. Liu; W. Cheng; G. Wiener; R. Frehlich; W. Mahoney; T. Warner; J. Himelic; K. Parks; S. Early

2010-01-01

196

Evaporation Tower With Prill Nozzles  

NASA Technical Reports Server (NTRS)

Tower more efficient than conventional evaporation equipment. Liquids such as milk and fruit juice concentrated by passing them through tiny nozzle to form droplets, then allowing droplets to fall through evacuated tower with cooled walls.

Du Fresne, E. R.

1984-01-01

197

Combined-cycle power tower.  

National Technical Information Service (NTIS)

This paper evaluates a new power tower concept that offers significant benefits for commercialization of power tower technology. The concept uses a molten nitrate salt centralreceiver plant to supply heat, in the form of combustion air preheat, to a conve...

M. S. Bohn, T. A. Williams, H. W. Price

1994-01-01

198

Thermal Characteristics of Heating Towers  

NASA Astrophysics Data System (ADS)

Thermal characteristics of heating towers for air-source heat pumps are studied in terms of the overall enthalpy-transfer coefficient. Ka. First. the method of counter-flow calculation is presented taking physical properties of ethylene glycol solutions into account. Next, both cooling-tower and heating-tower experiments are carried out in a small, induced-draft. counterflow tower packed with tubes of a staggerd arrangement. using water and commercial ethylene glycol solutions. The coefficient Ka measured in the heating-tower experiment shows a trend similar to that in the cooling-tower experiment. So. the data on cooling towers will be helpful to the thermal design of heating towers.

Fujita, Toshihiko; Kametani, Shigeki

199

Morpho Towers - Two Standing Spirals  

NSDL National Science Digital Library

This YouTube video by Sachiko Kodama, "Morpho Towers, Two Standing Spirals," shows a ferrofluid work of art. As music plays, the video shows ferrofluid patterns appearing and changing on two towers as electromagnets inside produce changing magnetic fields.

Kodama, Sachiko

2011-11-28

200

COOLING TOWER PLUME MODEL  

EPA Science Inventory

A review of recently reported cooling tower plume models yields none that is universally accepted. The entrainment and drag mechanisms and the effect of moisture on the plume trajectory are phenomena which are treated differently by various investigators. In order to better under...

201

A Neural Network Approach for Improving QuikSCAT Winds in Rain and Retrieving Liquid Water Estimates from QuikSCAT Data  

NASA Astrophysics Data System (ADS)

We describe a method for retrieving more accurate QuikSCAT winds in rainy conditions and obtaining an estimate of liquid water from the scatterometer measurements alone. The method utilizes an artificial neural network technique trained using SeaWinds/AMSR data and ECMWF analysis wind fields. The network is trained to estimate AMSR liquid water and ECMWF winds from scatterometer data alone. The accuracy of the resultant wind speeds slightly outperforms the AMSR rain corrected wind speeds available in the SeaWinds product and dramatically improves upon the scatterometer-only wind speeds. In addition to testing on SeaWinds on ADEOS-II data, one month of QuikSCAT winds were also processed by the network. Despite being trained on ECMWF, the network-retrieved QuikSCAT winds maintained geographical biases between ECMWF and QuikSCAT that were observed in the “rain free” official QuikSCAT data. On the other hand, wind features in the ECMWF fields that were completely obscured in rainy areas of QuikSCAT official wind products were clearly observed in the network processed winds. In addition to improving wind speed accuracy we also use the neural network to retrieve wind direction. Directional retrieval because of its multi-modal error characteristics is more problematic for the neural network. However, when the network is employed as a post processor in which MLE retrieved directions are inputs, significant directional improvement can also be obtained. Both statistical and pictorial evidence indicate that a neural network approach can be used to greatly improve scatterometer winds in the presence of rain. The root mean square speed difference between QuikSCAT and ECMWF winds drops from 7 m/s to 3 m/s for the subset of wind vector cells that were flagged for rain contamination. Images of QuikSCAT official and neural network winds in rain contaminated areas (as evidenced by co-located SSM/I rain rates) will be presented. These images show correlations between rainy areas in SSM/I and anomalous wind features in official QuikSCAT data. The anomalous wind regions disappear in the neural network wind fields. The images are not included here because they are much less informative when restricted to black and white. A different neural network is trained on simulated scatterometer measurements derived from WRF rain and wind field simulations that feed into a Mie-scattering model. This network is compared with the neural network trained from SeaWinds/AMSR data in order to determine to what extent the best available physical models can accurately reproduce the information we have used to improve the QuikSCAT winds.

Stiles, B. W.; Dunbar, R. S.; Hristova-Veleva, S. M.; Chau, A. H.; Martin, J. M.

2009-12-01

202

Application of Network Planning to Teaching Wind-Surfing  

ERIC Educational Resources Information Center

Study aim: To determine the effects of network planning on teaching untrained subjects windsurfing. Material and methods: Untrained physical education students (n = 390), aged 19-23 years, took part in the study while staying on a summer camp. They were randomly assigned into two groups: experimental (n = 216) and control (n = 174). Two methods of…

Zybko, Przemyslaw; Jaczynowski, Lech

2008-01-01

203

Unavailability of wind turbines due to wind-induced accelerations  

Microsoft Academic Search

The malfunctioning of acceleration-sensitive equipment in wind turbines has the potential to affect their annual failure rates during normal operating conditions. Current protective measures for wind turbines are triggered by wind speed. However, this option neglects the structural response of the wind turbines, and limits the possibility of effectively controlling accelerations at the top of the wind towers. In this

Leonardo Dueñas-Osorio; Biswajit Basu

2008-01-01

204

The Leaning Tower of Pisa  

NSDL National Science Digital Library

The official site of the Leaning Tower of Pisa offers users a comprehensive tour of this historic landmark with 6,400 images and two QTVR films. In addition to the exhaustive photographic tour, which illuminates almost every conceivable detail of the Tower's eight floors (help on navigating the photos is available), the site includes a nice history of the Tower from 1173 to the present, and a fourteen-part exhibit on the building's construction and efforts to conserve the Tower. Simply put, this is THE site for anyone interested in the Leaning Tower of Pisa. Naturally, the site is also available in Italian.

205

Tvind wind mill  

Microsoft Academic Search

The Tvind wind mill (Tvindkraftmuehle) is a 2-megawatt high-speed engine consisting of a tower, a blade-holder, and three blades. The tower is 53 m high, the blade-holder is cigar-shaped and rotates on the top of the tower, and the blades are 27 m long, up to 2.1 m wide, and weigh about 4500 kg. Forty rpm is maximum, and is

S. Kalke; J. Gjerding; F. Gustafsson

1977-01-01

206

A radar-based monitoring of the Collserola tower (Barcelona)  

NASA Astrophysics Data System (ADS)

This paper reports a set of experiments aiming at evaluating the capability of an innovative radar technique to measure the dynamic response of a 268 m high tower, the Collserola tower located in Barcelona, and its guys; the tension force of some guys is also estimated from the obtained vibration frequencies. The applied procedure was based on the use of a coherent radar system: temporal samples acquired using different observation geometries were processed to retrieve the vibration characteristics of both the tower and its guys. This was attained by observing the tower in a fully remote sensing mode, i.e. several hundred metres from the object, without installing any reflector on the tower, and under micro-tremor and wind-induced excitation. During the campaigns, which were spread over three years, the investigated technique demonstrated its capability to measure the dynamic response for a number of different points of the tower with high repeatability. The performed experiments also allowed distinguishing and characterizing the different contributions of the tower and the guys.

Luzi, G.; Crosetto, M.; Cuevas-González, M.

2014-12-01

207

Hanford Meteorological Station computer codes: Volume 5, The TOWER computer code  

SciTech Connect

The Hanford Meteorological Station (HMS), operated by Pacific Northwest Laboratory, archives wind, dry bulb temperature, and soil temperature data gathered each hour from the 410-ft meteorological tower. These data include measurements of wind speed and wind direction for seven heights, eight dry bulb temperatures, and three soil temperatures. The TOWER computer code is used to archive those measurements and apply quality assurance checks to the data. The code accesses an input file, which contains the previous archive's date and hour, and an output file, which contains tower weather observations for the current month. A data entry form consisting of 25 fields is included in the program. The fields must be filled in by the user. The information entered is appended to the monthly file, which provides an archive for the tower data gathered hourly. This volume describes the implementation and operation of the TOWER computer code at the HMS.

Buck, J.W.; Andrews, G.L.

1987-10-01

208

Solar power towers  

NASA Astrophysics Data System (ADS)

Experimental solar power towers actually in construction or already in existence in the world are described. Seven of these installations are examined: three involve water vapor with solar superheating (EURELIOS, CESA 1, SOLAR ONE); two involve saturated water vapor (NIO, CES 5); one involves sodium (SSPS, CRS), and one molten salt (TEMIS). The principal characteristics of these receivers are presented as well as some results of economic studies of heliostat construction and the cost of electricity.

Etievant, M. C.

1982-11-01

209

Prediction of Aerodynamic Coefficients for Wind Tunnel Data using a Genetic Algorithm Optimized Neural Network  

NASA Technical Reports Server (NTRS)

A fast, reliable way of predicting aerodynamic coefficients is produced using a neural network optimized by a genetic algorithm. Basic aerodynamic coefficients (e.g. lift, drag, pitching moment) are modelled as functions of angle of attack and Mach number. The neural network is first trained on a relatively rich set of data from wind tunnel tests of numerical simulations to learn an overall model. Most of the aerodynamic parameters can be well-fitted using polynomial functions. A new set of data, which can be relatively sparse, is then supplied to the network to produce a new model consistent with the previous model and the new data. Because the new model interpolates realistically between the sparse test data points, it is suitable for use in piloted simulations. The genetic algorithm is used to choose a neural network architecture to give best results, avoiding over-and under-fitting of the test data.

Rajkumar, T.; Aragon, Cecilia; Bardina, Jorge; Britten, Roy

2002-01-01

210

Assessment of Error in Synoptic-Scale Diagnostics Derived from Wind Profiler and Radiosonde Network Data  

NASA Technical Reports Server (NTRS)

A topic of current practical interest is the accurate characterization of the synoptic-scale atmospheric state from wind profiler and radiosonde network observations. We have examined several related and commonly applied objective analysis techniques for performing this characterization and considered their associated level of uncertainty both from a theoretical and a practical standpoint. A case study is presented where two wind profiler triangles with nearly identical centroids and no common vertices produced strikingly different results during a 43-h period. We conclude that the uncertainty in objectively analyzed quantities can easily be as large as the expected synoptic-scale signal. In order to quantify the statistical precision of the algorithms, we conducted a realistic observing system simulation experiment using output from a mesoscale model. A simple parameterization for estimating the uncertainty in horizontal gradient quantities in terms of known errors in the objectively analyzed wind components and temperature is developed from these results.

Mace, Gerald G.; Ackerman, Thomas P.

1996-01-01

211

Climatological summary of wind and temperature data for the Hanford Meteorology Monitoring Network  

SciTech Connect

This document presents climatological summaries of wind and temperature data collected at the twenty-five monitoring stations operated by the Hanford Meteorology Monitoring Network. The climatological analyses presented here involve hourly averaged wind data collected over an 8-year period beginning in 1982 (fewer wind data are available for the several monitoring stations that began full-time operation after 1982) and hourly averaged air temperature data collected over 2-year period beginning in mid-1988. The tables and figures presented in this document illustrate the spatial and temporal variation of meteorological parameters across the Hanford Site and the surrounding areas. This information is useful for emergency response applications, routine meteorological forecasting, planning and scheduling operations, facility design, and environmental impact studies.

Glantz, C.S.; Schwartz, M.N.; Burk, K.W.; Kasper, R.B.; Ligotke, M.W.; Perrault, P.J.

1990-09-01

212

Remote Survey of the Leaning Tower of Pisa by Interferometric Sensing  

Microsoft Academic Search

The Leaning Tower of Pisa, one of the world-famous architectural marvels of Italian heritage, needs continuous surveying to assess its stability. In this letter, remote-sensing equipment recently developed by the authors, based on the principle of microwave radar interferometry, has been experimented to measure the frequency response of the Tower without requiring any contact with its structure. Wind and human

Carlo Atzeni; Alberto Bicci; Devis Dei; Matteo Fratini; Massimiliano Pieraccini

2010-01-01

213

Remote Survey of the Leaning Tower of Pisa by Interferometric Sensing  

Microsoft Academic Search

9 any contact with its structure. Wind and human traffic were used 10 as natural excitation sources, allowing the natural frequencies 11 of the first vibration mode of the Tower to be measured in the 12 north-south and in the west-east directions. Modal shapes of 13 the Tower vibrations were also obtained from data acquired by 14 the radar. 15

Carlo Atzeni; Alberto Bicci; Devis Dei; Matteo Fratini; Massimiliano Pieraccini

2009-01-01

214

30 m Stable towers for optimum astronomical observations at dome c/concordia  

NASA Astrophysics Data System (ADS)

This paper gives an overview of conceptual studies that have been realized since 2007 on 30 m towers for Dome C taking into account local available infrastructures and conditions. Some 30 m tower's concepts are presented and finite element simulations are carried to determine their dynamic behaviour including wind-induced vibrations, and to optimize their design.

Dournaux, J.-L.; Amans, J.-P.; Damé, L.; Le Moigne, J.

215

MPPT control strategy for wind energy conversion system based on RBF network  

Microsoft Academic Search

This paper presents maximum-power-point-tracking (MPPT) based control algorithms for optimal wind energy capture using radial basis function network (RBFN) and a proposed torque observer MPPT algorithm. The design of a high-performance on-line training RBFN using back-propagation learning algorithm regulating controller for the sensorless control of a permanent magnet synchronous generator (PMSG). The PMSG is controlled by the loss-minimization control with

Whei-Min Lin; Chih-Ming Hong; Fu-Sheng Cheng; Kai Hung Lu

2011-01-01

216

STATISTICAL CORRELATIONS OF SURFACE WIND DATA: A COMPARISON BETWEEN A NATIONAL WEATHER SERVICE STATION AND A NEARBY AEROMETRIC MONITORING NETWORK  

EPA Science Inventory

This report presents a statistical analysis of wind data collected at a network of stations in the Southeast Ohio River Valley. The purpose of this study is to determine the extent to which wind measurements made by the National Weather Service (NWS) station at the Tri-State Airp...

217

Initial Operation Results and Performance Evaluation of WINDS (Wideband Inter-Networking engineering test and Demonstration Satellite)  

NASA Astrophysics Data System (ADS)

WINDS was launched in late February 2008 to demonstrate technologies enabling an ultra-high data rate communication network. WINDS is performing initial functional verifications of onboard components and systems. This paper describes the initial operation results on orbit and evaluates the performance based on the design and simulation data.

Arikawa, Yoshihisa; Nakamura, Yasuo; Araki, Tsunehiko; Fujiwara, Yuuichi; Baba, Isao; Baba, Kenichi

218

Impact of fixed and variable speed wind generators on the transient stability of a power system network  

Microsoft Academic Search

This paper compares the effect of fixed speed and variable speed grid-connected wind generators on the transient stability of a power system network. The wind generators considered are the squirrel cage induction generator (SCIG), which is a fixed speed, the doubly-fed induction generator (DFIG) and the converter driven synchronous generator (CDSG) which are variable speed. Two scenarios are investigated. Under

K. A. Folly; S. Sheetekela

2009-01-01

219

Operational Wind Retrieval Within the Frame of the French Weather Radar Network  

NASA Astrophysics Data System (ADS)

The recent deployment of an innovative triple-PRT Doppler scheme within the French operational radar network, named ARAMIS, allows collecting reflectivity and radial velocity measurements simultaneously up to a range of 250 km with no ambiguity. This achievement brings new perspectives in terms of exploitation of operational radar measurements such as the long-anticipated capability to perform multiple-Doppler wind retrieval in a fully operational framework. Accordingly, and for the first time ever, a method allowing to consistently retrieve complete wind vector fields (u, v, w) in real-time from operational radar systems is being tested by the French national weather service since early 2007. This study proposes to describe the experimental setup relied upon to operationally retrieve multiple-Doppler winds in the frame of ARAMIS, as well as to investigate the potential of this new product for weather forecast applications. Using high resolution numerical wind forecasts in a variety of weather situations, we also show that these radar-derived wind fields compose unprecedented datasets to evaluate and further improve high-resolution numerical weather prediction systems being currently deployed by many national weather services.

Bousquet, O.; Tabary, P.; Parent-Du-Châtelet, J.; Périer, L.

2008-12-01

220

An Annotated Bibliography of Meteorological Tower and Mast Studies - WB/Bs-5.  

National Technical Information Service (NTIS)

The bibliography consists of sources containing meteorological data and information obtained from towers and mast. Primary interest is on wind data. All available sources in the U. S. Department of Commerce, Atmospheric Sciences Library, Environmental Sci...

J. A. Wallace

1967-01-01

221

New Scientist: Construction of Worlds Largest Tower to Begin  

NSDL National Science Digital Library

This article from the New Scientist talks about the building of the world's tallest building in Dubai, United Arab Emirates. The tower construction will be completed in 2008 and will result in a structure 800 meters tall. The article discusses how the building has been designed to address a primary concern for buildings of this height--wind.

222

Periodic pulsations from a three-bladed wind turbine  

Microsoft Academic Search

In this paper, periodic power pulsations from a three-bladed wind turbine are analyzed. The influence of wind shear, wind speed, turbulence intensity, rotor position and tower oscillation is investigated. No clear dependence between the periodic power components and the wind shear or turbulence intensity has been verified. The investigated turbine sometimes produces large power pulsations at the tower resonance frequency.

Torbjörn Thiringer; Jan-Åke Dahlberg

2001-01-01

223

Peak Wind Tool for General Forecasting  

NASA Technical Reports Server (NTRS)

This report describes work done by the Applied Meteorology Unit (AMU) in predicting peak winds at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The 45th Weather Squadron requested the AMU develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. Based on observations from the KSC/CCAFS wind tower network , Shuttle Landing Facility (SLF) surface observations, and CCAFS sounding s from the cool season months of October 2002 to February 2007, the AMU created mul tiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence , the temperature inversion depth and strength, wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft.

Barrett, Joe H., III; Short, David

2008-01-01

224

Wind power. [electricity generation  

NASA Technical Reports Server (NTRS)

A historical background on windmill use, the nature of wind, wind conversion system technology and requirements, the economics of wind power and comparisons with alternative systems, data needs, technology development needs, and an implementation plan for wind energy are presented. Considerable progress took place during the 1950's. Most of the modern windmills feature a wind turbine electricity generator located directly at the top of their rotor towers.

Savino, J. M.

1975-01-01

225

CO2, CO, and CH4 measurements from tall towers in the NOAA Earth System Research Laboratory's Global Greenhouse Gas Reference Network: instrumentation, uncertainty analysis, and recommendations for future high-accuracy greenhouse gas monitoring efforts  

NASA Astrophysics Data System (ADS)

A reliable and precise in situ CO2 and CO analysis system has been developed and deployed at eight sites in the NOAA Earth System Research Laboratory's (ESRL) Global Greenhouse Gas Reference Network. The network uses very tall (> 300 m) television and radio transmitter towers that provide a convenient platform for mid-boundary-layer trace-gas sampling. Each analyzer has three sample inlets for profile sampling, and a complete vertical profile is obtained every 15 min. The instrument suite at one site has been augmented with a cavity ring-down spectrometer for measuring CO2 and CH4. The long-term stability of the systems in the field is typically better than 0.1 ppm for CO2, 6 ppb for CO, and 0.5 ppb for CH4, as determined from repeated standard gas measurements. The instrumentation is fully automated and includes sensors for measuring a variety of status parameters, such as temperatures, pressures, and flow rates, that are inputs for automated alerts and quality control algorithms. Detailed and time-dependent uncertainty estimates have been constructed for all of the gases, and the uncertainty framework could be readily adapted to other species or analysis systems. The design emphasizes use of off-the-shelf parts and modularity to facilitate network operations and ease of maintenance. The systems report high-quality data with > 93% uptime. Recurrent problems and limitations of the current system are discussed along with general recommendations for high-accuracy trace-gas monitoring. The network is a key component of the North American Carbon Program and a useful model for future research-grade operational greenhouse gas monitoring efforts.

Andrews, A. E.; Kofler, J. D.; Trudeau, M. E.; Williams, J. C.; Neff, D. H.; Masarie, K. A.; Chao, D. Y.; Kitzis, D. R.; Novelli, P. C.; Zhao, C. L.; Dlugokencky, E. J.; Lang, P. M.; Crotwell, M. J.; Fischer, M. L.; Parker, M. J.; Lee, J. T.; Baumann, D. D.; Desai, A. R.; Stanier, C. O.; De Wekker, S. F. J.; Wolfe, D. E.; Munger, J. W.; Tans, P. P.

2014-02-01

226

Efficient pricing for European electricity networks – The theory of nodal pricing applied to feeding-in wind in Germany  

Microsoft Academic Search

This paper applies nodal pricing as an economic approach to efficient use of electricity networks utilization for the fairly large German grid. We combine a straightforward welfare maximization with the technical specificities of electricity flows on a realistically large network. The nodal pricing model is applied in order to analyze the impact of extended German wind power production on the

Florian Leuthold; Hannes Weigt; Christian von Hirschhausen

2008-01-01

227

FLORIDA TOWER FOOTPRINT EXPERIMENTS  

SciTech Connect

The Florida Footprint experiments were a series of field programs in which perfluorocarbon tracers were released in different configurations centered on a flux tower to generate a data set that can be used to test transport and dispersion models. These models are used to determine the sources of the CO{sub 2} that cause the fluxes measured at eddy covariance towers. Experiments were conducted in a managed slash pine forest, 10 km northeast of Gainesville, Florida, in 2002, 2004, and 2006 and in atmospheric conditions that ranged from well mixed, to very stable, including the transition period between convective conditions at midday to stable conditions after sun set. There were a total of 15 experiments. The characteristics of the PFTs, details of sampling and analysis methods, quality control measures, and analytical statistics including confidence limits are presented. Details of the field programs including tracer release rates, tracer source configurations, and configuration of the samplers are discussed. The result of this experiment is a high quality, well documented tracer and meteorological data set that can be used to improve and validate canopy dispersion models.

WATSON,T.B.; DIETZ, R.N.; WILKE, R.; HENDREY, G.; LEWIN, K.; NAGY, J.; LECLERC, M.

2007-01-01

228

Short-term load and wind power forecasting using neural network-based prediction intervals.  

PubMed

Electrical power systems are evolving from today's centralized bulk systems to more decentralized systems. Penetrations of renewable energies, such as wind and solar power, significantly increase the level of uncertainty in power systems. Accurate load forecasting becomes more complex, yet more important for management of power systems. Traditional methods for generating point forecasts of load demands cannot properly handle uncertainties in system operations. To quantify potential uncertainties associated with forecasts, this paper implements a neural network (NN)-based method for the construction of prediction intervals (PIs). A newly introduced method, called lower upper bound estimation (LUBE), is applied and extended to develop PIs using NN models. A new problem formulation is proposed, which translates the primary multiobjective problem into a constrained single-objective problem. Compared with the cost function, this new formulation is closer to the primary problem and has fewer parameters. Particle swarm optimization (PSO) integrated with the mutation operator is used to solve the problem. Electrical demands from Singapore and New South Wales (Australia), as well as wind power generation from Capital Wind Farm, are used to validate the PSO-based LUBE method. Comparative results show that the proposed method can construct higher quality PIs for load and wind power generation forecasts in a short time. PMID:24807030

Quan, Hao; Srinivasan, Dipti; Khosravi, Abbas

2014-02-01

229

Floating wind turbine system  

NASA Technical Reports Server (NTRS)

A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

Viterna, Larry A. (Inventor)

2009-01-01

230

Prediction of wind-induced pressures on long-span roofs with complex shape using artificial neural networks  

Microsoft Academic Search

The backpropagation neural network(BPNN) and the radial basis function neural network(RBF) are widely employed to simulate many kinds of nonlinear relationships, and have received increasing interests in recent years. This paper is concerned with the above two artificial neural networks for the prediction of mean wind-induced pressures of two long-span roof structures, the Shenzhen Citizen Center(SCC) and the Guangzhou International

An Xu; Ruohong Zhao

2010-01-01

231

Hybrid Evaporative - Condenser Cooling Tower  

Microsoft Academic Search

The need to save energy in power producing and power consuming systems and the fact that evaporative cooling is the most efficient method for heat rejection led to the design and testing of a model of a special cooling tower, fn this hybrid system an evaporative condenser is being built into the cooling tower and the advantages of evaporative cooling

Uriyel Fisher; Wolfgang Leidenfrost; Jiashang Li

1981-01-01

232

Weird Geology: The Devil's Tower  

NSDL National Science Digital Library

This page features a brief introduction to the several theories about the geological processes that formed Devil's Tower, which rises 1,267 feet above the nearby Belle Fourche River and is still considered a sacred place by some Native American Tribes. Information on climbing the tower as well as images and a cross section are provided.

Krystek, Lee; Mystery, The M.

233

The Leaning Tower of Pisa  

Microsoft Academic Search

THE photograph of the ``Leaning'' Tower of Pisa in NATURE of August 4 shows clearly that the top tier is not square with the rest. From a rough alignment with the edge of a postcard, the photograph appears as if the tower was of the order of 25 mm.\\/metre out of plumb when the top tier was put on presumably

Edward G. Brown

1910-01-01

234

The Leaning Tower of Pisa  

Microsoft Academic Search

THIS famous tower will doubtless always be a question, like the man in the iron mask and other historical mysteries. Most architects, however, will be very slow to believe that it would have been built intentionally leaning on the general grounds that, however adventurous the architect, the clients would not have stood it. The analogy of the leaning towers of

Arthur T. Bolton

1910-01-01

235

Cooling Tower Modification for Intermittent Operation.  

National Technical Information Service (NTIS)

One of the cooling towers at Los Alamos Scientific Laboratory is being operated intermittently. The cooling tower has been modified to restrict air flow and to keep the tower from drying out. The modifications are relatively inexpensive, simple to operate...

W. S. Midkiff

1975-01-01

236

Observing wind, aerosol particles, cloud and precipitation: Finland's new ground-based remote-sensing network  

NASA Astrophysics Data System (ADS)

The Finnish Meteorological Institute, in collaboration with the University of Helsinki, has established a new ground-based remote-sensing network in Finland. The network consists of five topographically, ecologically and climatically different sites distributed from southern to northern Finland. The main goal of the network is to monitor air pollution and boundary layer properties in near real time, with a Doppler lidar and ceilometer at each site. In addition to these operational tasks, two sites are members of the Aerosols, Clouds, and Trace gases Research InfraStructure Network (ACTRIS); a Ka-band Doppler cloud radar at Sodankylä will provide cloud retrievals within CloudNet, and a multi-wavelength Raman lidar, POLLYXT (POrtabLe Lidar sYstem eXTended), in Kuopio provides optical and microphysical aerosol properties through EARLINET (European Aerosol Research Lidar Network to Establish an Aerosol Climatology). Three C-band weather radars are located in the Helsinki metropolitan area and are deployed for operational and research applications. We carried out two inter-comparison campaigns to investigate the Doppler lidar performance. The aims of the campaigns were to compare the backscatter coefficient and retrieved wind profiles, and to optimise the lidar sensitivity through adjusting the telescope focus and data-integration time to ensure enough signals in low-aerosol-content environments. The wind profiles showed good agreement between different lidars. However, due to inaccurate telescope focus setting and varying receiver sensitivity, backscatter coefficient profiles showed disagreement between the lidars. Harsh Finnish winters could pose problems, but, due to the built-in heating systems, low ambient temperatures had no, or only a minor, impact on the lidar operation: including scanning-head motion. However, accumulation of snow and ice on the lens has been observed, which can lead to formation of a water/ice layer thus attenuating the signal inconsistently. Thus, care must be taken to ensure continuous snow removal.

Hirsikko, A.; O'Connor, E. J.; Komppula, M.; Korhonen, K.; Pfüller, A.; Giannakaki, E.; Wood, C. R.; Bauer-Pfundstein, M.; Poikonen, A.; Karppinen, T.; Lonka, H.; Kurri, M.; Heinonen, J.; Moisseev, D.; Asmi, E.; Aaltonen, V.; Nordbo, A.; Rodriguez, E.; Lihavainen, H.; Laaksonen, A.; Lehtinen, K. E. J.; Laurila, T.; Petäjä, T.; Kulmala, M.; Viisanen, Y.

2013-08-01

237

LWST Phase I Project Conceptual Design Study: Evaluation of Design and Construction Approaches for Economical Hybird Steel/Concrete Wind Turbine Towers. (Report for June 28, 2002-July 31, 2004).  

National Technical Information Service (NTIS)

The United States Department of Energy (DOE) Wind Energy Research Program has begun a new effort to partner with U.S. industry to develop wind technology that will allow wind systems to compete in regions of low wind speed. The Class 4 and 5 sites targete...

M. W. LaNier

2005-01-01

238

Dry cooling tower operating experience in the LOFT reactor  

SciTech Connect

A dry cooling tower has been uniquely utilized to dissipate heat generated in a small experimental pressurized water nuclear reactor. Operational experience revealed that dry cooling towers can be intermittently operated with minimal wind susceptibility and water hammer occurrences by cooling potential steam sources after a reactor scram, by isolating idle tubes from the external atmosphere, and by operating at relatively high pressures. Operating experience has also revealed that tube freezing can be minimized by incorporating the proper heating and heat loss prevention features.

Hunter, J.A.

1980-01-01

239

How do towers measure anything?  

NASA Astrophysics Data System (ADS)

Limitations to achieving plausible long-term observational values for heat, water vapor and CO2 fluxes at the individual sites in the tower flux networks are discussed. a) Operational difficulties mean that few sites that operate over years obtain data more than 70-80% of the time. To satisfy modelers, "gap-filling" techniques-models in themselves are called upon to provide seamless data sets. b) The observational energy balance regularly does not close by up to 20% of available energy, net radiation minus the ground heat. Most studies report that the sum of sensible and latent heat flux does not account for the observed available energy. c) CO2 eddy fluxes are sometimes judged to be "ecologically incorrect" if comparisons with rival measurement techniques lead to implausible amounts of uptake. There is perceived to be "missing flux" problem, one that might result from averaging in the definition of the eddy flux ensemble mean. They might as well reflect loss of scalars horizontally in subcanopy flows, especially at night. Some of the increasingly elaborate theoretical corrections being proposed to rectify these problems will be critiqued, from the point of view of the humble field observer. Many of these corrections rely on there being accurate estimates of the mean vertical velocity, for example, a notoriously difficult measurement to make. Selected examples from recent work at ASRC will serve to illustrate major points.

Fitzjarrald, D. R.

2001-05-01

240

SkyTower Telecommunications  

NSDL National Science Digital Library

Helios is the name of an unmanned, solar powered aircraft that broke many records and made history on its first successful flight last summer. With more flights scheduled for this summer, there is growing interest in the potential applications of so-called "atmospheric satellites" like Helios. This Web site, operated by the company that developed the prototype, has lots of information about the aircraft, its specifications, and, most importantly, its possible uses. The main focus is on telecommunications; because this kind of aircraft could remain at high altitudes for long periods of time, it could be used as an extremely tall tower that relays signals to and from ground stations. A video clip demonstrating this technology is also provided on the site.

241

The Tower of London  

NSDL National Science Digital Library

As one of the most famous complexes of historic structures in the world, it stands to reason that the Tower of London would have a plethora of websites dedicated to exploring its development and rather crucial role in English history. Begun by William the Conquerer, the castle has been improved and added upon numerous times over the past 900 years, and now includes dozens of smaller structures within its walls. Developed by staff members at Knight International, this site is a real treat for those seeking to learn more about this historic site, or those who might be planning a visit in the future. The site contains approximately a dozen different areas of interest, ranging from a fine virtual tour of the grounds, a section devoted to the omnipresent ravens and, of course, a copious amount of materials on the Crown Jewels.

242

Development of large wind energy power generation system  

NASA Technical Reports Server (NTRS)

The background and development of an experimental 100 kW wind-energy generation system are described, and the results of current field tests are presented. The experimental wind turbine is a two-bladed down-wind horizontal axis propeller type with a 29.4 m diameter rotor and a tower 28 m in height. The plant was completed in March, 1983, and has been undergoing trouble-free tests since then. The present program calls for field tests during two years from fiscal 1983 to 1984. The development of technologies relating to the linkage and operation of wind-energy power generation system networks is planned along with the acquisition of basic data for the development of a large-scale wind energy power generation system.

1985-01-01

243

Direct adaptive control of wind energy conversion systems using Gaussian networks.  

PubMed

Grid connected wind energy conversion systems (WECS) present interesting control demands, due to the intrinsic nonlinear characteristics of windmills and electric generators. In this paper a direct adaptive control strategy for WECS control is proposed. It is based on the combination of two control actions: a radial basis zfunction network-based adaptive controller, which drives the tracking error to zero with user specified dynamics, and a supervisory controller, based on crude bounds of the system's nonlinearities. The supervisory controller fires when the finite neural-network approximation properties cannot be guaranteed. The form of the supervisor control and the adaptation law for the neural controller are derived from a Lyapunov analysis of stability. The results are applied to a typical turbine/generator pair, showing the feasibility of the proposed solution. PMID:18252585

Mayosky, M A; Cancelo, I E

1999-01-01

244

Scanning Doppler Lidar Measurements for Wind Energy Applications  

Microsoft Academic Search

The development of wind energy has increased rapidly along with the size and capacity of wind turbines. These larger machines require detailed wind resource measurements at higher and higher altitudes. Accurate wind speed, wind direction, and turbulence statistics are required for wind resource assessment and efficient wind farm operation. Tower measurements are limited in coverage and do not provide the

R. Frehlich; N. Kelley

2008-01-01

245

Wind-Driven Wireless Networked System of Mobile Sensors for Mars Exploration  

NASA Technical Reports Server (NTRS)

A revolutionary way is proposed of studying the surface of Mars using a wind-driven network of mobile sensors: GOWON. GOWON would be a scalable, self-powered and autonomous distributed system that could allow in situ mapping of a wide range of environmental phenomena in a much larger portion of the surface of Mars compared to earlier missions. It could improve the possibility of finding rare phenomena such as "blueberries' or bio-signatures and mapping their occurrence, through random wind-driven search. It would explore difficult terrains that were beyond the reach of previous missions, such as regions with very steep slopes and cluttered surfaces. GOWON has a potentially long life span, as individual elements can be added to the array periodically. It could potentially provide a cost-effective solution for mapping wide areas of Martian terrain, enabling leaving a long-lasting sensing and searching infrastructure on the surface of Mars. The system proposed here addresses this opportunity using technology advances in a distributed system of wind-driven sensors, referred to as Moballs.

Davoodi, Faranak; Murphy, Neil

2013-01-01

246

Prediction of the Dst index from solar wind parameters by a neural network method  

NASA Astrophysics Data System (ADS)

Using the Elman-type neural network technique, operational models are constructed that predict the Dst index two hours in advance. The input data consist of real-time solar wind velocity, density, and magnetic field data obtained by the Advanced Composition Explorer (ACE) spacecraft since May 1998 (http://www2.crl.go.jp/uk/uk223/service/nnw/index.html). During the period from February to October 1998, eleven storms occurred with minimum Dst values below -80 nT. For ten of these storms the differences between the predicted minimum Dst and the minimum Dst calculated from ground-based magnetometer data were less than 23%. For the remaining one storm (beginning on 19 October 1998) the difference was 48%. The discrepancy is likely to stem from a imperfect correlation between the solar wind parameters near ACE and those near the earth. While the IMF Bz remains to be the most important parameter, other parameters do have their effects. For instance, Dst appears to be enhanced when the azimuthal direction of IMF is toward the sun. A trapezoid-shaped increase in the solar wind density enhances the main phase Dst by almost 10% compared with the case of no density increase. Velocity effects appear to be stronger than the density effects. Our operational models have, in principle, no limitations in applicability with respect to storm intensity.

Watanabe, S.; Sagawa, E.; Ohtaka, K.; Shimazu, H.

2002-12-01

247

Data Quality Assessment Methods for the Eastern Range 915 MHz Wind Profiler Network  

NASA Technical Reports Server (NTRS)

The Eastern Range installed a network of five 915 MHz Doppler Radar Wind Profilers with Radio Acoustic Sounding Systems in the Cape Canaveral Air Station/Kennedy Space Center area to provide three-dimensional wind speed and direction and virtual temperature estimates in the boundary layer. The Applied Meteorology Unit, staffed by ENSCO, Inc., was tasked by the 45th Weather Squadron, the Spaceflight Meteorology Group, and the National Weather Service in Melbourne, Florida to investigate methods which will help forecasters assess profiler network data quality when developing forecasts and warnings for critical ground, launch and landing operations. Four routines were evaluated in this study: a consensus time period check a precipitation contamination check, a median filter, and the Weber-Wuertz (WW) algorithm. No routine was able to effectively flag suspect data when used by itself. Therefore, the routines were used in different combinations. An evaluation of all possible combinations revealed two that provided the best results. The precipitation contamination and consensus time routines were used in both combinations. The median filter or WW was used as the final routine in the combinations to flag all other suspect data points.

Lambert, Winifred C.; Taylor, Gregory E.

1998-01-01

248

PBF Cooling Tower. Hot deck of Cooling Tower with fan ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PBF Cooling Tower. Hot deck of Cooling Tower with fan motors in place. Fan's propeller blades (not in view) rotate within lower portion of vents. Inlet pipe is a left of view. Contractor's construction buildings in view to right. Photographer: Larry Page. Date: June 30, 1969. INEEL negative no. 69-3781 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

249

Integrated control of wind farms, FACTS devices and the power network using neural networks and adaptive critic designs  

NASA Astrophysics Data System (ADS)

Worldwide concern about the environmental problems and a possible energy crisis has led to increasing interest in clean and renewable energy generation. Among various renewable energy sources, wind power is the most rapidly growing one. Therefore, how to provide efficient, reliable, and high-performance wind power generation and distribution has become an important and practical issue in the power industry. In addition, because of the new constraints placed by the environmental and economical factors, the trend of power system planning and operation is toward maximum utilization of the existing infrastructure with tight system operating and stability margins. This trend, together with the increased penetration of renewable energy sources, will bring new challenges to power system operation, control, stability and reliability which require innovative solutions. Flexible ac transmission system (FACTS) devices, through their fast, flexible, and effective control capability, provide one possible solution to these challenges. To fully utilize the capability of individual power system components, e.g., wind turbine generators (WTGs) and FACTS devices, their control systems must be suitably designed with high reliability. Moreover, in order to optimize local as well as system-wide performance and stability of the power system, real-time local and wide-area coordinated control is becoming an important issue. Power systems containing conventional synchronous generators, WTGs, and FACTS devices are large-scale, nonlinear, nonstationary, stochastic and complex systems distributed over large geographic areas. Traditional mathematical tools and system control techniques have limitations to control such complex systems to achieve an optimal performance. Intelligent and bio-inspired techniques, such as swarm intelligence, neural networks, and adaptive critic designs, are emerging as promising alternative technologies for power system control and performance optimization. This work focuses on the development of advanced optimization and intelligent control algorithms to improve the stability, reliability and dynamic performance of WTGs, FACTS devices, and the associated power networks. The proposed optimization and control algorithms are validated by simulation studies in PSCAD/EMTDC, experimental studies, or real-time implementations using Real Time Digital Simulation (RTDS) and TMS320C6701 Digital Signal Processor (DSP) Platform. Results show that they significantly improve electrical energy security, reliability and sustainability.

Qiao, Wei

250

World Federation of Great Towers  

NSDL National Science Digital Library

The World Federation of Great Towers (WFGT) "is an association of international monuments which join together to foster global awareness and develop international opportunities for promotion." The organization provides this eye-catching site that contains detailed information and pictures of over twenty towers from around the world. After giving a brief background summary of each tower's location and notable characteristics, specifications and technical data are provided to give an impression of the scale of the structures and the engineering skill that was needed in their construction. Although only the buildings that are members of the WFGT are featured online, the collection does a good job of capturing some of the most impressive towers in existence.

251

Ozonation of cooling tower waters  

NASA Technical Reports Server (NTRS)

Continuous ozone injection into water circulating between a cooling tower and heat exchanger with heavy scale deposits inhibits formation of further deposits, promotes flaking of existing deposits, inhibits chemical corrosion and controls algae and bacteria.

Humphrey, M. F.; French, K. R.; Howe, R. D. (inventors)

1979-01-01

252

An Analysis of Peak Wind Speed Data from Collocated Mechanical and Ultrasonic Anemometers  

NASA Technical Reports Server (NTRS)

This study focuses on a comparison of peak wind speeds reported by mechanical and ultrasonic anemometers at Cape Canaveral Air Force Station and Kennedy Space Center (CCAFS/KSC) on the east central coast of Florida and Vandenberg Air Force Base (VAFB) on the central coast of California. The legacy mechanical wind instruments on CCAFS/KSC and VAFB weather towers are being changed from propeller-and-vane (CCAFS/KSC) and cup-and-vane (VAFB) sensors to ultrasonic sensors under the Range Standardization and Automation (RSA) program. The wind tower networks on KSC/CCAFS and VAFB have 41 and 27 towers, respectively. Launch Weather Officers, forecasters, and Range Safety analysts at both locations need to understand the performance of the new wind sensors for a myriad of reasons that include weather warnings, watches, advisories, special ground processing operations, launch pad exposure forecasts, user Launch Commit Criteria (LCC) forecasts and evaluations, and toxic dispersion support. The Legacy sensors measure wind speed and direction mechanically. The ultrasonic RSA sensors have no moving parts. Ultrasonic sensors were originally developed to measure very light winds (Lewis and Dover 2004). The technology has evolved and now ultrasonic sensors provide reliable wind data over a broad range of wind speeds. However, because ultrasonic sensors respond more quickly than mechanical sensors to rapid fluctuations in speed, characteristic of gusty wind conditions, comparisons of data from the two sensor types have shown differences in the statistics of peak wind speeds (Lewis and Dover 2004). The 45th Weather Squadron (45 WS) and the 30 WS requested the Applied Meteorology Unit (AMU) to compare data from RSA and Legacy sensors to determine if there are significant differences in peak wind speed information from the two systems.

Short, David A.; Wells, Leonard A.; Merceret, Francis J.; Roeder, William P.

2005-01-01

253

The Physics of Shot Towers  

ERIC Educational Resources Information Center

In the late 18th and throughout the 19th century, lead shot for muskets was prepared by use of a shot tower. Molten lead was poured from the top of a tower and, during its fall, the drops became spherical under the action of surface tension. In this article, we ask and answer the question: "How does the size of the lead shot depend on the height…

Lipscombe, Trevor C.; Mungan, Carl E.

2012-01-01

254

Tornado type wind turbines  

DOEpatents

A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.

Hsu, Cheng-Ting (Ames, IA) [Ames, IA

1984-01-01

255

Observing wind, aerosol particles, cloud and precipitation: Finland's new ground-based remote-sensing network  

NASA Astrophysics Data System (ADS)

The Finnish Meteorological Institute, in collaboration with the University of Helsinki, has established a new ground-based remote-sensing network in Finland. The network consists of five topographically, ecologically and climatically different sites distributed from southern to northern Finland. The main goal of the network is to monitor air pollution and boundary layer properties in near real time, with a Doppler lidar and ceilometer at each site. In addition to these operational tasks, two sites are members of the Aerosols, Clouds and Trace gases Research InfraStructure Network (ACTRIS); a Ka band cloud radar at Sodankylä will provide cloud retrievals within CloudNet, and a multi-wavelength Raman lidar, PollyXT (POrtabLe Lidar sYstem eXTended), in Kuopio provides optical and microphysical aerosol properties through EARLINET (the European Aerosol Research Lidar Network). Three C-band weather radars are located in the Helsinki metropolitan area and are deployed for operational and research applications. We performed two inter-comparison campaigns to investigate the Doppler lidar performance, compare the backscatter signal and wind profiles, and to optimize the lidar sensitivity through adjusting the telescope focus length and data-integration time to ensure sufficient signal-to-noise ratio (SNR) in low-aerosol-content environments. In terms of statistical characterization, the wind-profile comparison showed good agreement between different lidars. Initially, there was a discrepancy in the SNR and attenuated backscatter coefficient profiles which arose from an incorrectly reported telescope focus setting from one instrument, together with the need to calibrate. After diagnosing the true telescope focus length, calculating a new attenuated backscatter coefficient profile with the new telescope function and taking into account calibration, the resulting attenuated backscatter profiles all showed good agreement with each other. It was thought that harsh Finnish winters could pose problems, but, due to the built-in heating systems, low ambient temperatures had no, or only a minor, impact on the lidar operation - including scanning-head motion. However, accumulation of snow and ice on the lens has been observed, which can lead to the formation of a water/ice layer thus attenuating the signal inconsistently. Thus, care must be taken to ensure continuous snow removal.

Hirsikko, A.; O'Connor, E. J.; Komppula, M.; Korhonen, K.; Pfüller, A.; Giannakaki, E.; Wood, C. R.; Bauer-Pfundstein, M.; Poikonen, A.; Karppinen, T.; Lonka, H.; Kurri, M.; Heinonen, J.; Moisseev, D.; Asmi, E.; Aaltonen, V.; Nordbo, A.; Rodriguez, E.; Lihavainen, H.; Laaksonen, A.; Lehtinen, K. E. J.; Laurila, T.; Petäjä, T.; Kulmala, M.; Viisanen, Y.

2014-05-01

256

Tower Temperature and Humidity Sensors (TWR) Handbook  

SciTech Connect

Three tall towers are installed at the Atmospheric Radiation Measurement (ARM) Climate Research Facility: a 60-meter triangular tower at the Southern Great Plains (SGP) Central Facility (CF), a 21-meter walkup scaffolding tower at the SGP Okmulgee forest site (E21), and a 40-meter triangular tower at the North Slope of Alaska (NSA) Barrow site. The towers are used for meteorological, radiological, and other measurements.

Cook, DR

2010-02-01

257

Comparative analysis of neural network and regression based condition monitoring approaches for wind turbine fault detection  

NASA Astrophysics Data System (ADS)

This paper presents the research results of a comparison of three different model based approaches for wind turbine fault detection in online SCADA data, by applying developed models to five real measured faults and anomalies. The regression based model as the simplest approach to build a normal behavior model is compared to two artificial neural network based approaches, which are a full signal reconstruction and an autoregressive normal behavior model. Based on a real time series containing two generator bearing damages the capabilities of identifying the incipient fault prior to the actual failure are investigated. The period after the first bearing damage is used to develop the three normal behavior models. The developed or trained models are used to investigate how the second damage manifests in the prediction error. Furthermore the full signal reconstruction and the autoregressive approach are applied to further real time series containing gearbox bearing damages and stator temperature anomalies. The comparison revealed all three models being capable of detecting incipient faults. However, they differ in the effort required for model development and the remaining operational time after first indication of damage. The general nonlinear neural network approaches outperform the regression model. The remaining seasonality in the regression model prediction error makes it difficult to detect abnormality and leads to increased alarm levels and thus a shorter remaining operational period. For the bearing damages and the stator anomalies under investigation the full signal reconstruction neural network gave the best fault visibility and thus led to the highest confidence level.

Schlechtingen, Meik; Ferreira Santos, Ilmar

2011-07-01

258

Thin film sensor network for condition assessment of wind turbine blades  

NASA Astrophysics Data System (ADS)

Existing sensing solutions facilitating continuous condition assessment of wind turbine blades are limited by a lack of scalability and clear link signal-to-prognosis. With recent advances in conducting polymers, it is now possible to deploy networks of thin film sensors over large areas, enabling low cost sensing of large-scale systems. Here, we propose to use a novel sensing skin consisting of a network of soft elastomeric capacitors (SECs). Each SEC acts as a surface strain gage transducing local strain into measurable changes in capacitance. Using surface strain data facilitates the extraction of physics-based features from the signals that can be used to conduct condition assessment. We investigate the performance of an SEC network at detecting damages. Diffusion maps are constructed from the time series data, and changes in point-wise diffusion distances evaluated to determine the presence of damage. Results are benchmarked against time-series data produced from off-the-shelf resistive strain gauges. This paper presents data from a preliminary study. Results show that the SECs are promising, but the capability to perform damage detection is currently reduced by the presence of parasitic noise in the signal.

Laflamme, Simon; Saleem, Hussam; Venkatesh, Chinde; Vaidya, Umesh; Sarkar, Partha; Sauder, Heather

2014-03-01

259

Detail of antenna tower structure, looking northnorthwest OvertheHorizon Backscatter ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail of antenna tower structure, looking north-northwest - Over-the-Horizon Backscatter Radar Network, Tulelake Radar Site Receive Sector Five Antenna Array, Unnamed Road West of Double Head Road, Tulelake, Siskiyou County, CA

260

Vibration Control of Bridge Tower Under Construction Using Active Mass Damper  

NASA Astrophysics Data System (ADS)

For large structures such as towers of suspension bridges or cable-stayed bridges, we often need to suppress wind-induced vibration for safety. Especially in the construction stage, the structures have a low tolerance than completed ones. This paper discusses the active vibration dampers used to suppress wind-induced vibration of a tower of a suspension bridge during a construction. The active damper was used to suppress wind-induced vibration in multiple modes predicted by wind-tunnel test. The controller design of the dampers is based on H? robust control theory. At each erection step, we measured dynamic properties of towers to adjust parameters of the controller using active vibration exciters. The measured dynamic properties of active controlled structures are compared with those of non-controlled structures. The analysis of free vibration shows the suppression performance of active damper as expected in the controller design.

Kagaya, Hiroaki; Tamaki, Toshihiro; Nishi, Yoshikazu; Nagao, Yoichi; Yamaguchi, Kazunori

261

Wind Farm Feasibility Study  

Microsoft Academic Search

Saint Francis University has assessed the Swallow Farm property located in Shade Township, Somerset County, Pennsylvania as a potential wind power development site. Saint Francis worked with McLean Energy Partners to have a 50-meter meteorological tower installed on the property in April 2004 and continues to conduct a meteorological assessment of the site. Results suggest a mean average wind speed

Richard Curry; Erik Foley; DOE Project Officer

2007-01-01

262

Reluctance Network Model of Turbo-Generator and its Application in Rotor Winding InterTurn Short Circuit Fault  

Microsoft Academic Search

The reluctance network model of non-salient pole generator is presented, and the generator status differential equations are developed, whose parameters are stator winding branch current, stator reluctance, rotor reluctance, air-gap reluctance, rotor magnetomotive force. Its main advantages are to take into the rotor movement and saturation effects, with a good compromise between calculation time and accuracy of results. Then the

Wan Shuting; Wang Aimeng; Li Yonggang; Wang Yi

2005-01-01

263

A neural network study of the mapping from solar magnetic fields to the daily average solar wind velocity  

Microsoft Academic Search

Predictions of the daily solar wind velocity (V) at 1 AU from the flux tube expansion factor fs are examined with radial basis function neural networks. The flux tube expansion factor is calculated from the potential field model, using Wilcox Solar Observatory magnetograms, with the source surface placed at 2.5 solar radii. The time series extend over 20 years from

Peter Wintoft; Henrik Lundstedt

1999-01-01

264

Numerical study of the performance of tornado-type wind energy systems  

Microsoft Academic Search

The results of an analytical investigation of the effects of changing the parameters and operating conditions of a tornado-type wind energy system are presented. The tornado tower system comprises a tower over the turbine exhaust. A vortex is formed within the tower, and contains a low pressure area at core, which enhances the wind flow velocity through the turbine. Various

S. S. Ayad

1983-01-01

265

Influence of Wind Turbulence on Yaw-control Gears in Wind Turbine  

Microsoft Academic Search

This paper describes an influence of wind turbulence on yaw-control gears of nacelle in a wind power station. This site is located in Tappi cape of Aomori prefecture where is characterized by a big wind turbulence due to the western strong wind and a steep slope of the cape. In this paper two adjacent wind towers are dealt with among

Kazuo Suzuki; Naoki Hoshino; Noboru Inomata; Hiroshi Kimura; Tamiya Fujiwara

2009-01-01

266

Mapping carbon flux uncertainty and selecting optimal locations for future flux towers in the Great Plains  

USGS Publications Warehouse

Flux tower networks (e. g., AmeriFlux, Agriflux) provide continuous observations of ecosystem exchanges of carbon (e. g., net ecosystem exchange), water vapor (e. g., evapotranspiration), and energy between terrestrial ecosystems and the atmosphere. The long-term time series of flux tower data are essential for studying and understanding terrestrial carbon cycles, ecosystem services, and climate changes. Currently, there are 13 flux towers located within the Great Plains (GP). The towers are sparsely distributed and do not adequately represent the varieties of vegetation cover types, climate conditions, and geophysical and biophysical conditions in the GP. This study assessed how well the available flux towers represent the environmental conditions or "ecological envelopes" across the GP and identified optimal locations for future flux towers in the GP. Regression-based remote sensing and weather-driven net ecosystem production (NEP) models derived from different extrapolation ranges (10 and 50%) were used to identify areas where ecological conditions were poorly represented by the flux tower sites and years previously used for mapping grassland fluxes. The optimal lands suitable for future flux towers within the GP were mapped. Results from this study provide information to optimize the usefulness of future flux towers in the GP and serve as a proxy for the uncertainty of the NEP map.

Gu, Y.; Howard, D. M.; Wylie, B. K.; Zhang, L.

2012-01-01

267

SMUD Kokhala Power Tower Study  

SciTech Connect

Kokhala is the name of a new hybridized power tower design which integrates a nitrate-salt solar power tower with a gas turbine combined-cycle power plant. This integration achieves high value energy, low costs, and lower investor risk than a conventional solar only power tower plant. One of the primary advantages of this system is that it makes small power tower plants much more economically competitive with conventional power generation technologies. This paper is an overview of a study that performed a conceptual evaluation of a small (30 MWe) commercial plant suitable for the Sacramento Municipal Utility District`s (SMUD) Rancho Seco power plant site near Sacramento, California. This paper discusses the motivation for using a small hybrid solar plant and provides an overview of the analysis methodology used in the study. The results indicate that a power tower integrated with an advanced gas turbine, combined with Sacramento`s summer solar resource, could produce a low- risk, economically viable power generation project in the near future.

Price, Henry W. [National Renewable Energy Laboratory, Golden, CO (United States); Whitney, Daniel D.; Beebe, H.I. [Sacramento Municipal Utility District, CA (United States)

1997-06-01

268

Estimation of a nacelle dynamic motion of a wind turbine  

Microsoft Academic Search

A Kalman filter is applied to estimate the movement of a nacelle. The information of nacelle acceleration and strain gauge installed at the root location of tower is combined in Kalman filtering. A simple model of tower vibration is considered. A scale-down experimental rig simulating a tower and nacelle of wind turbine is constructed to test the performance of proposed

Yoonsu Nam; Taejun Yoon; Kyoseon Kim; Pham Hung Cuong

2008-01-01

269

RBF neural network based PI pitch controller for a class of 5-MW wind turbines using particle swarm optimization algorithm.  

PubMed

In order to control the pitch angle of blades in wind turbines, commonly the proportional and integral (PI) controller due to its simplicity and industrial usability is employed. The neural networks and evolutionary algorithms are tools that provide a suitable ground to determine the optimal PI gains. In this paper, a radial basis function (RBF) neural network based PI controller is proposed for collective pitch control (CPC) of a 5-MW wind turbine. In order to provide an optimal dataset to train the RBF neural network, particle swarm optimization (PSO) evolutionary algorithm is used. The proposed method does not need the complexities, nonlinearities and uncertainties of the system under control. The simulation results show that the proposed controller has satisfactory performance. PMID:22738782

Poultangari, Iman; Shahnazi, Reza; Sheikhan, Mansour

2012-09-01

270

Winds  

NSDL National Science Digital Library

In this problem-based learning (PBL) scenario, students prepare a presentation for investors showing how their fishing company has a significant advantage because it locates upwelling zones and fishing areas using TRMM (Tropical Rainfall Measuring Mission) and other satellite data. Prior to launching the PBL, students learn about wind: the topics of air pressure, coriolis effect, upwelling and the role of differential heating on the atmosphere are explored in classroom demonstrations. Materials required include a beaker, coffee grounds, drinking straw, balloon, flashlight, and turntable. The resource includes teacher background information, glossary, assessment rubric, and an appendix introducing problem-based learning.

271

Establishment of a Meso-network of Eddy Covariance Towers to Quantify Carbon, Water and Heat Fluxes Along a Permafrost and Climate Gradient in the Taiga Plains, Northwest Territories, Canada  

NASA Astrophysics Data System (ADS)

Recent research suggests an increase in active-layer depth in the continuous permafrost zone and degradation of the sporadic and discontinuous permafrost zones into seasonally frozen ground. Increasing active-layer depth and continued permafrost degradation will have far-reaching consequences for northern ecosystems with net feedbacks of unknown magnitude and direction to the climate system by altered regional hydrology and topography, vegetation composition and structure, land surface properties, and carbon dioxide (CO2) and methane (CH4) sink-source strengths. Several important questions are currently unanswered: 1) What is the net effect of permafrost thawing-induced biophysical and biogeochemical feedbacks to the climate system? 2) How do these two different types of feedback differ between the sporadic, discontinuous and continuous permafrost zones? 3) Is the decrease (increase) in net CO2 (CH4) exchange measured over mostly tundra sites in the continuous permafrost zone generalizable to forested landscapes in the sporadic, discontinuous and continuous permafrost zones? To address these questions we initiated a meso-network of eddy covariance towers to quantify carbon (CO2, CH4), water and heat fluxes along a permafrost and climate gradient in the Taiga Plains, Northwest Territories, Canada including the following four sites from south to north (Fort Simpson - Norman Wells - Inuvik): Scotty Creek (boreal forest-peatland landscape with sporadic/discontinuous permafrost; fully operational since May 2013), Norman Wells (boreal forest with discontinuous/continuous permafrost; to be established in 2014), Havikpak Creek (boreal forest with continuous permafrost; partly operational since April 2013) and Trail Valley Creek (tundra with continuous permafrost; partly operational since April 2013). At all sites the eddy covariance measurements are or will be complemented by repeated surveys of surface and frost table topography and vegetation, by land cover-type specific fluxes of CO2 and CH4 measured with a static chamber technique, and by remote sensing-based footprint analysis. With this contribution, we report on the current status of meso-network development and present results from the first growing season of eddy covariance measurements at Scotty Creek, Trail Valley Creek and Havikpak Creek. Net CO2 uptake started earlier and was more pronounced at the forested Havikpak site compared to the tundra site (Trail Valley Creek), which experienced similar air temperatures but later snow melt than Havikpak. Overall, Scotty Creek experienced the strongest net CO2 uptake but also the highest nighttime respiration. At the same time, meteorological conditions at Scotty Creek are markedly different with higher air temperatures and earlier snowmelt than at the two northern sites.

Sonnentag, O.; Helbig, M.; Detto, M.; Wischnewski, K.; Chasmer, L.; Marsh, P.; Quinton, W. L.

2013-12-01

272

Wind turbine  

SciTech Connect

A wind turbine assembly including a rotor body is described having mounted thereon a plurality of rotor blades, wherein each of the rotor blades is joined at an inner extremity the blade stem projection extending interiorly into the rotor body and secured there within to the rotor body by torsional- and axial-shock damping connection means, wherein each blade stem projection comprises a hollow cylindrical housing defining a central longitudinal axis therein, with a support member interiorly disposed in the housing at an intermediate position along its axis and fixedly secured to the housing, a shaft fixedly secured at one end thereof to the rotor body and coupled at its other end with the support member in a manner allowing limited axial and rotational movement of the housing relative to the rotor body, and a longitudinally outwardly biasing means between the support member and the rotor body, extending along the axis of the housing and outwardly abuttingly biased against the support member, whereby the biasing means provides torsional and axial shock damping to the rotor blade. The wind turbine assembly includes a nacelle to which the rotor body is coupled for rotation with respect to the nacelle, and a tower having an upper portion to which the nacelle is secured by coupling means, and a lower portion positionable on a support body, the tower upper portion including a cylindrical member at an upper end of the tower, an oarlock connector joined to the bottom stem portion; a pitch biasing and damping member interconnecting the nacelle and the oarlock connector, for pitch damping of the nacelle; and yaw biasing and damping means connecting the oarlock and upper portion of the tower, whereby the pitch damping/biasing member and the yaw biasing and damping means bias the rotor body and nacelle to a selected base position in relation to the tower, and dampen pitch and yaw displacements from said base position.

Lundquist, R.E.

1993-05-25

273

Income loss due to wind energy rejected by the Crete island electrical network – the present situation  

Microsoft Academic Search

During the last 4 years, a substantial wind energy penetration was encountered mainly in the Greek mainland. At the same time, limited size new wind-parks were built in the numerous Greek islands, although their wind potential is clearly higher than the one for the mainland and their wind energy generation could be used to replace electricity produced by diesel engines

J. K. Kaldellis; K. A. Kavadias; A. E. Filios; S. Garofallakis

2004-01-01

274

Cooling tower windage: a new aspect to environmental assessment  

SciTech Connect

Results of the several investigations provided quantitative estimates of windage from Oak Ridge Gaseous Diffusion Plant cooling towers. Windage water deposited on the ground has the potential to reach nearby streams through runoff. Windage deposited on moisture depleted soils would not be significant. During winter months at Oak Ridge soils generally have a high moisture content such that windage deposition could be quickly transported as runoff. It is during this time that cooling towers are sometimes operated without fan-induced draft. Since windage water contains the same hexavalent chromium concentration (9 ppM) as the recirculating cooling water system, the runoff stream from the K-892J tower constitues a NPDES violation as an unpermitted discharge. As a long-term abatement strategy, concrete aprons were constructed along each side of new cooling towers at the Paducah, Kentucky Gaseous Diffusion Plant. The maximum distance of windage impact is wind dependent. If apron construction is envisioned as an abatement strategy at Oak Ridge, the maximum distance of impact can be inferred graphically from the several points where windage (fans off) and drift (fans on) loss curves intersect under the different meteorological conditions. Once the hexavalent chromium laden runoff stream reaches Poplar Creek, it is diluted well below the standards for drinking water and poses little potential for biological effects to aquatic systems.

Taylor, F.G.; Park, S.H.

1980-01-01

275

Study of aerodynamical interference for a wind turbine  

Microsoft Academic Search

A two-dimensional interference model of upwind wind turbine, based on NREL Phase VI, was simulated by an available Navier–Stokes solver under parallel process. The simulation domain was divided into a stationary tower domain and a sliding blade domain with varying geometric factors, including blade chord to tower diameter ratio and tower-blade gap to tower diameter ratio, to figure out the

Shy-Yea Lin; Tzong-Hann Shieh

2010-01-01

276

Winding for the wind  

NASA Technical Reports Server (NTRS)

The mechanical properties and construction of epoxy-impregnated fiber-glass blades for wind turbines are discussed, along with descriptions of blades for the Mod 0A and Mod 5A WECS and design goals for a 4 kW WECS. Multicell structure combined with transverse filament tape winding reduces labor and material costs, while placing a high percentage of 0 deg fibers spanwise in the blades yields improved strength and elastic properties. The longitudinal, transverse, and shear modulus are shown to resist stresses exceeding the 50 lb/sq ft requirements, with constant stress resistance expected until fatigue failure is approached. Regression analysis indicates a fatigue life of 400 million operating cycles. The small WECS under prototype development features composite blades, nacelle, and tower. Rated at 5.7 kW in a 15 mph wind, the machine operates over a speed range of 9-53.9 mph and is expected to produce 16,200 kWh annually in a 10 mph average wind measured at 30 ft.

Weingart, O.

1981-01-01

277

Winding for the wind  

NASA Astrophysics Data System (ADS)

The mechanical properties and construction of epoxy-impregnated fiber-glass blades for wind turbines are discussed, along with descriptions of blades for the Mod 0A and Mod 5A WECS and design goals for a 4 kW WECS. Multicell structure combined with transverse filament tape winding reduces labor and material costs, while placing a high percentage of 0 deg fibers spanwise in the blades yields improved strength and elastic properties. The longitudinal, transverse, and shear modulus are shown to resist stresses exceeding the 50 lb/sq ft requirements, with constant stress resistance expected until fatigue failure is approached. Regression analysis indicates a fatigue life of 400 million operating cycles. The small WECS under prototype development features composite blades, nacelle, and tower. Rated at 5.7 kW in a 15 mph wind, the machine operates over a speed range of 9-53.9 mph and is expected to produce 16,200 kWh annually in a 10 mph average wind measured at 30 ft.

Weingart, O.

278

Asbestos in cooling-tower waters  

Microsoft Academic Search

Fill material in natural- or mechanical-draft cooling towers can be manufactured from a variety of materials, including asbestos cement or asbestos paper. To aid in the environmental impact assessment of cooling towers containing these asbestos types of fill, information on these materials was obtained from cooling-tower vendors and users. Samples of makeup, basin, and blowdown waters at a number of

B. A. G

1977-01-01

279

Alternative water treatment for cooling towers  

Microsoft Academic Search

Problems commonly found in cooling towers include: calcium scale formation, corrosion, algae and bacterial growth. These problems can inhibit a cooling tower from operating at its most efficient capacity. An energy-saving, cost-efficient method to control each of these problems in tower water will ultimately benefit the owner as well as the environment. Supplemental ionic water purification was developed to overcome

Wilsey

1997-01-01

280

Optimal Inflatable Space Towers of High Height  

Microsoft Academic Search

Author provides theory and computations for building inflatable space towers up to a hundred km in height. These towers can be used for tourism; scientific observation of space, earth's surface, weather, top atmosphere, as well as for radio, television, and communication transmissions. These towers can also be used to launch space ships and Earth satellites. These projects are not expensive

Alexander Bolonkin

2002-01-01

281

Verification of BModes: Rotary Beam and Tower Modal Analysis Code; Preprint  

SciTech Connect

This paper describes verification of BModes, a finite-element code developed to provide coupled modes for the blades and tower of a wind turbine. The blades, which may be rotating or non-rotating, and the towers, whether onshore or offshore, are modeled using specialized 15-dof beam finite elements. Both blade and tower models allow a tip attachment, which is assumed to be rigid body with six moments of inertia, and a mass centroid that may be offset from the blade or tower axis. Examples of tip attachments are aerodynamic brakes for blades and nacelle-rotor subassembly for towers. BModes modeling allows for tower supports including tension wires, floating platforms, and monopiles on elastic foundations. Coupled modes (implying coupling of flap, lag, axial, and torsional motions) are required for modeling major flexible components in a modal-based, aeroelastic code such as FAST1. These are also required for validation of turbine models using experimental data, modal-based fatigue analysis, controls design, and understanding aeroelastic-stability behavior of turbines. Verification studies began with uniform tower models, with and without tip inertia, and progressed to realistic towers. For the floating turbine, we accounted for the effects of hydrodynamic inertia, hydrostatic restoring, and mooring lines stiffness. For the monopole-supported tower, we accounted for distributed hydrodynamic mass on the submerged part of the tower and for distributed foundation stiffness. Finally, we verified a model of a blade carrying tip mass and rotating at different speeds (verifications of other blade models, rotating or non-rotating, have been reported in another paper.) Verifications were performed by comparing BModes-generated modes with analytical results, if available, or with MSC.ADAMS results. All results in general show excellent agreement.

Bir, G.

2010-04-01

282

Wind Turbines States Classification by a Fuzzy-ART Neural Network with a Stereographic Projection as a Signal Normalization  

Microsoft Academic Search

\\u000a In this paper wind turbines operational states classification is considered. The fuzzy-ART neural network is proposed as a\\u000a classifying system. Applying of stereographic projection as an input signals normalization procedure is introduced. Both theoretical\\u000a justification is discussed and results of experiments are presented. It turns out that the introduced normalization procedure\\u000a improves classification results.

Tomasz Barszcz; Marzena Bielecka; Andrzej Bielecki; Mateusz Wójcik

2011-01-01

283

WindFloat: A floating foundation for offshore wind turbines  

Microsoft Academic Search

This manuscript summarizes the feasibility study conducted for the WindFloat technology. The WindFloat is a three-legged floating foundation for multimegawatt offshore wind turbines. It is designed to accommodate a wind turbine, 5 MW or larger, on one of the columns of the hull with minimal modifications to the nacelle and rotor. Potential redesign of the tower and of the turbine

Dominique Roddier; Christian Cermelli; Alexia Aubault; Alla Weinstein

2010-01-01

284

Robust fault detection of wind energy conversion systems based on dynamic neural networks.  

PubMed

Occurrence of faults in wind energy conversion systems (WECSs) is inevitable. In order to detect the occurred faults at the appropriate time, avoid heavy economic losses, ensure safe system operation, prevent damage to adjacent relevant systems, and facilitate timely repair of failed components; a fault detection system (FDS) is required. Recurrent neural networks (RNNs) have gained a noticeable position in FDSs and they have been widely used for modeling of complex dynamical systems. One method for designing an FDS is to prepare a dynamic neural model emulating the normal system behavior. By comparing the outputs of the real system and neural model, incidence of the faults can be identified. In this paper, by utilizing a comprehensive dynamic model which contains both mechanical and electrical components of the WECS, an FDS is suggested using dynamic RNNs. The presented FDS detects faults of the generator's angular velocity sensor, pitch angle sensors, and pitch actuators. Robustness of the FDS is achieved by employing an adaptive threshold. Simulation results show that the proposed scheme is capable to detect the faults shortly and it has very low false and missed alarms rate. PMID:24744774

Talebi, Nasser; Sadrnia, Mohammad Ali; Darabi, Ahmad

2014-01-01

285

Evaluation of Wind Forecasts and Observation Impacts using Variational and Ensemble Data Assimilation over the WFIP Southern Study Region  

NASA Astrophysics Data System (ADS)

Accurate, high-resolution wind ramp forecasting is crucial to efficient wind power systems. Two of the primary goals of the DOE-NOAA Weather Forecast Improvement Project (WFIP) were to understand how wind ramp forecasts vary with regard to 1) different data assimilation systems, and 2) an enhanced observational network. This study examines the quality of wind ramp and day-to-day wind forecasts with the Weather Research and Forecasting (WRF) mesoscale model using two independent data assimilation systems: the Gridpoint Statistical Interpolation (GSI) three-dimensional variational (3DVAR) system, and the Data Assimilation Research Testbed (DART) ensemble Kalman filter (EnKF). 0-24hr forecasts of 10 wind ramp events at existing wind farms are verified against 80-meter meteorological tower data, and lower atmospheric winds are also verified against 80-meter tower data, surface observations, and radiosonde observations over a month-long period. These experiments are conducted at 12km and 3km grid spacing over a project domain centered over Texas. Furthermore, the observational impacts of both surface mesonet observations, as well as sodar and profiler observations aloft deployed during the project, are assessed for both the ramp cases and the month-long period.

Ancell, B. C.

2013-12-01

286

HIERARCHAL CONTROL SYSTEM FOR A VARIABLE SPEED CAGE MACHINE WIND GENERATION UNIT USING NEURAL NETWORKS  

Microsoft Academic Search

A hierarchal control strategy, that addresses three control objectives for a wind generation system, is proposed in this paper. It controls the local bus voltage (to avoid voltage rise), captures the maximum power in the wind and also minimizes the power loss in the induction generator. In the first level, given the instantaneous wind speed, electrical torque and output power,

M. Karrari; W. Rosehart; O. P. Malik

2005-01-01

287

NON-DIVERGENT WIND ANALYSIS ALGORITHM FOR THE ST. LOUIS RAPS (REGIONAL AIR POLLUTION STUDY) NETWORK  

EPA Science Inventory

An objective wind analysis algorithm capable of producing non-divergent wind fields at up to ten levels in the atmospheric boundary layer for St. Louis, Missouri is described. Wind data collected during the St. Louis Regional Air Pollution Study (RAPS) and averaged over 15-minute...

288

A Dynamic Wind Turbine Simulator of the Wind Turbine Generator System  

Microsoft Academic Search

To study dynamic performances of wind turbine generator system (WTGS), and to determine the control structures in laboratory. The dynamic torque generated by wind turbine (WT) must be simulated. In there paper, a dynamic wind turbine emulator (WTE) is designed, which consider wind shear and tower shadow effect, and a dynamic torque compensation scheme is also developed to compensate the

Lei Lu; Zhen Xie; Xing Zhang; Shuying Yang; Renxian Cao

2012-01-01

289

Laboratory-scale experiments on wind turbine nacelle movement estimation  

Microsoft Academic Search

The effect of nacelle motion should be considered when calculating the wind speed relative to the wind turbine structure, which is essential in wind turbine control and performance testing. A Kalman filter approach is applied to estimate the nacelle motion of a wind turbine. Information from several accelerometers and strain gauges which are installed on the wind turbine tower is

Yoonsu Nam; Tai Jun Yoon

2009-01-01

290

Airport Remote Tower Sensor Systems  

NASA Technical Reports Server (NTRS)

Remote Tower Sensor Systems (RTSS) are proof-of-concept prototypes being developed by NASA/Ames Research Center (NASA/ARC) with collaboration with the FAA (Federal Aviation Administration) and NOAA (National Oceanic Atmospheric Administration). RTSS began with the deployment of an Airport Approach Zone Camera System that includes real-time weather observations at San Francisco International Airport. The goal of this research is to develop, deploy, and demonstrate remotely operated cameras and sensors at several major airport hubs and un-towered airports. RTSS can provide real-time weather observations of airport approach zone. RTSS will integrate and test airport sensor packages that will allow remote access to realtime airport conditions and aircraft status.

Papasin, Richard; Gawdiak, Yuri; Maluf, David A.; Leidich, Christopher; Tran, Peter B.

2001-01-01

291

A Vortical Hot Tower Route to Tropical Cyclogenesis.  

NASA Astrophysics Data System (ADS)

A nonhydrostatic cloud model is used to examine the thermomechanics of tropical cyclogenesis under realistic meteorological conditions. Observations motivate the focus on the problem of how a midtropospheric cyclonic vortex, a frequent by-product of mesoscale convective systems during summertime conditions over tropical oceans, may be transformed into a surface-concentrated (warm core) tropical depression. As a first step, the vortex transformation is studied in the absence of vertical wind shear or zonal flow.Within the cyclonic vorticity-rich environment of the mesoscale convective vortex (MCV) embryo, the simulations demonstrate that small-scale cumulonimbus towers possessing intense cyclonic vorticity in their cores [vortical hot towers (VHTs)] emerge as the preferred coherent structures. The VHTs acquire their vertical vorticity through a combination of tilting of MCV horizontal vorticity and stretching of MCV and VHT-generated vertical vorticity. Horizontally localized and exhibiting convective lifetimes on the order of 1 h, VHTs overcome the generally adverse effects of downdrafts by consuming convective available potential energy in their local environment, humidifying the middle and upper troposphere, and undergoing diabatic vortex merger with neighboring towers.During metamorphosis, the VHTs vortically prime the mesoscale environment and collectively mimic a quasi-steady diabatic heating rate within the MCV embryo. A quasi-balanced toroidal (transverse) circulation develops on the system scale that converges cyclonic vorticity of the initial MCV and small-scale vorticity anomalies generated by subsequent tower activity. The VHTs are found to accelerate the spinup of near-surface mean tangential winds relative to an approximate axisymmetric model that excises the VHTs. This upscale growth mechanism appears capable of generating a tropical depression vortex on time scales on the order of 1 2 days, for reasonable parameter choices.Further tests of the VHT paradigm are advocated through diagnoses of operational weather prediction models, higher resolution simulations of the current configuration, examination of disruption scenarios for incipient vortices, and a meteorological field experiment.

Montgomery, M. T.; Nicholls, M. E.; Cram, T. A.; Saunders, A. B.

2006-01-01

292

National-Scale Wind Resource Assessment for Power Generation (Presentation)  

SciTech Connect

This presentation describes the current standards for conducting a national-scale wind resource assessment for power generation, along with the risk/benefit considerations to be considered when beginning a wind resource assessment. The presentation describes changes in turbine technology and viable wind deployment due to more modern turbine technology and taller towers and shows how the Philippines national wind resource assessment evolved over time to reflect changes that arise from updated technologies and taller towers.

Baring-Gould, E. I.

2013-08-01

293

Towards a Wind Energy Climatology at Advanced Turbine Hub-Heights: Preprint  

SciTech Connect

Measurements of wind characteristics over a wide range of heights up to and above 100 m are useful to: (1) characterize the local and regional wind climate; (2) validate wind resource estimates derived from numerical models; and (3) evaluate changes in wind characteristics and wind shear over the area swept by the blades. Developing wind climatology at advanced turbine hub heights for the United States benefits wind energy development. Tall tower data from Kansas, Indiana, and Minnesota (which have the greatest number of tall towers with measurement data) will be the focus of this paper. Analyses of data from the tall towers will start the process of developing a comprehensive climatology.

Schwartz, M.; Elliott, D.

2005-05-01

294

Data for tower baffle design  

SciTech Connect

Towers with baffles sometimes exhibit flooding of the baffle section. Yet there was insufficient pressure drop and capacity data to design a better baffle. Therefore, an experimental tower was used to collect the necessary data. Two types of baffles were tested: segmental and shower-deck. The data collected included: maximum vapor and liquid rates, distance of liquid curtain from the baffle edge, depth of liquid over the perforations of the shower deck, and pressure drop. The experimental apparatus consisted of a rectangular lucite tower (18 inches by 62 1/4 inches) in which three baffles were installed on 24-inch spacing. Data were obtained using an air-water system. Segmental baffles were run with 50% and 61.5% free area. They were also operated at 50% free area with 12-inch restriction plates. Shower-deck baffles were run with 1/4- and 3/4-inchdiameter holes with 4- and 8-inch weirs. The baffle free area was 40.2%. Some commercial data are reported on operation of segmental and shower-deck baffles.

Lemieux, E.J.

1983-09-01

295

Monitoring of wind pressure distribution at a supertall structure above maximum gradient wind level (presentation video)  

NASA Astrophysics Data System (ADS)

While the field measurement of wind speed at buildings and towers has been made by numerous investigators, the direct measurement of wind pressure at high-rise structures was seldom reported. Up to now, the information regarding wind pressure distribution above the maximum gradient wind level (it is 450 m stipulated in the Chinese code) has never been experimentally obtained. This paper presents a field monitoring investigation on the measurement of wind pressure and its distribution at the Canton Tower of 600 m high above the maximum gradient wind level during the typhoon Kaitak.

Ni, Y. Q.; Wang, Y. W.; Song, S. D.

2014-04-01

296

Aeroelastic analysis of wind energy conversion systems  

NASA Technical Reports Server (NTRS)

An aeroelastic investigation of horizontal axis wind turbines is described. The study is divided into two simpler areas; (1) the aeroelastic stability of a single blade on a rigid tower; and (2) the mechanical vibrations of the rotor system on a flexible tower. Some resulting instabilities and forced vibration behavior are described.

Dugundji, J.

1978-01-01

297

Lightning current distribution to ground at a power line tower carrying a radio base station  

Microsoft Academic Search

Radio base stations are often mounted on towers of power transmission lines. They are usually powered from the low-voltage network through an isolating transformer, to separate the high- and low-voltage networks. The isolating transformer ensures security at customers' premises in the case of nearby power faults and particularly in case of lightning striking, which is a frequent cause of flashover

Leonid Grcev; A. P. J. van Deursen; J. B. M. van Waes

2005-01-01

298

DETECTION OF CENTRIPETAL HEAT-ISLAND CIRCULATIONS FROM TOWER DATA IN ST. LOUIS  

EPA Science Inventory

Hourly averaged meteorological data gathered by a 25-tower network about St. Louis during 1976 are used in a search for centripetal circulations generated by the urban heat island. Considering data collected when the network resultant speed was less than 1.5 m/s, two data classes...

299

Wind Turbine With Concentric Ducts  

NASA Technical Reports Server (NTRS)

Wind Turbine device is relatively compact and efficient. Converging inner and outer ducts increase pressure difference across blades of wind turbine. Turbine shaft drives alternator housed inside exit cone. Suitable for installation on such existing structures as water towers, barns, houses, and commercial buildings.

Muhonen, A. J.

1983-01-01

300

Control scheme of PMSG based wind turbine for utility network connection  

Microsoft Academic Search

With the growing of electrical energy demand, wind energy gains higher potential and plays a vital role in energy sectors. Direct driven permanent magnet synchronous generator (PMSG) with a full size back-to-back converter set is one of the promising technologies employed with wind power generation. This paper focuses on developing a control scheme of PMSG-based wind turbines to obtain maximum

Ahmed A. Daoud; Sobhy S. Dessouky; Ahmed A. Salem

2011-01-01

301

The Use of Full-Physics Atmospheric Modeling for Wind Power Plants  

NASA Astrophysics Data System (ADS)

This presentation will describe a number of issues relevant to the use of mesoscale meteorological models for the development and operation of wind power plants. An accurate description of the local winds over a range of spatial and temporal scales is important for wind plants. In addition to various measurement methods, a number of modeling tools can be used to explore winds at these scales, including a full-physics mesoscale model such as the Weather Research and Forecasting (WRF) model. Simulations in regions of complex terrain can, however, have significant amounts of uncertainty, and results can be sensitive to the model parameters such as turbulence representation, the horizontal and vertical grid spacing, and initial and boundary conditions. Numerous studies conducted by PNNL scientists have quantified the performance of WRF. These evaluations included simulation of low-level winds in a number of geographic areas with both simple and complex terrain. However, previous research focused on comparisons with data from intensive, short-duration field campaigns that may not be completely relevant for wind plants. The identification of long- term, high quality data sets is therefore an important aspect of evaluating and improving model performance in wind energy applications. One such source of quality-assured meteorological data is from the US Department of Energy's Hanford Site. It is an ideal location for evaluating the performance of the WRF model for both prognosis of the local winds, as would be appropriate for a wind resource characterization, and for an analysis of severe wind events, which is important for wind turbine safety. The Hanford Site is located in southeastern Washington State and covers approximately 1500 sq km. The topography in this region is dominated by a number of significant ridges around a central basin, and severe wind events are frequent, especially during the springtime. Wind energy has been explored in this area, and a wind plant with a 96 mW capacity has recently been installed nearby. The Hanford Meteorological Monitoring Network, which consists of 30 stations, including a station near the top of Rattlesnake Mountain (approximately 1 km above the basin floor), a 120 m tower near the center of the basin, and three 60 m towers, was developed to provide real-time support to activities around the Hanford Site. The network has been operational, with its calibrated data archived, for more than 60 years, providing high-quality long-term observations well-suited for these wind energy modeling studies. This presentation will describe the evaluation of WRF using data from the Hanford Meteorological Monitoring Network. PNNL-SA-62301

Flaherty, J. E.; Berg, L. K.; Fast, J. D.; Gustafson, W. I.; Rishel, J. P.; Shaw, W. J.

2008-12-01

302

Pitch angle control in wind turbines above the rated wind speed by multi-layer perceptron and radial basis function neural networks  

Microsoft Academic Search

In wind energy conversion systems, one of the operational problems is the changeability and discontinuity of wind. In most cases, wind speed can fluctuate rapidly. Hence, quality of produced energy becomes an important problem in wind energy conversion plants. Several control techniques have been applied to improve the quality of power generated from wind turbines. Pitch control is the most

Ahmet Serdar Yilmaz; Zafer Özer

2009-01-01

303

40M Open Air Foucault Pendulum of Eurajoki Water Tower, Finland.  

National Technical Information Service (NTIS)

A method of exploiting tall buildings like water towers for school pendulum experiments is described. A 40m long Foucault pendulum with a heavy bob is relatively insensitive even to moderate winds if used outdoors. This is especially so at high latitudes ...

J. O. Mattila

1986-01-01

304

Design and analysis of portable loadless wind power source for ubiquitous sensor network  

Microsoft Academic Search

Nowadays, green technology solution using natural power such as solar, wind, waves et al. has been interested as an alternative power source instead of battery. This paper presents a portable power source driven by natural wind power. One of very efficient energy conversion mechanisms to change mechanical energy of natural power with electrical energy is a direct piezoelectric effect. However,

Hyung-Kwan Chang; Daejoong Kim

2010-01-01

305

Ride-Through Capability Predictions for Wind Power Plants in the ERCOT Network.  

National Technical Information Service (NTIS)

Utility system operators and engineers now want a better understanding of the impacts of large wind farms on grid stability before the farms are interconnected to the grid. Utilities need wind farm electrical models and methods of analysis that will help ...

E. Muljadi C. P. Butterfield J. Conto K. Donohoo

2005-01-01

306

Protection from ground faults in the stator winding of generators at power plants in the Siberian networks  

SciTech Connect

The experience of many years of experience in developing and utilization of ground fault protection in the stator winding of generators in the Siberian networks is generalized. The main method of protection is to apply a direct current or an alternating current with a frequency of 25 Hz to the primary circuits of the stator. A direct current is applied to turbo generators operating in a unit with a transformer without a resistive coupling to the external grid or to other generators. Applying a 25 Hz control current is appropriate for power generation systems with compensation of a capacitive short circuit current to ground. This method forms the basis for protection of generators operating on busbars, hydroelectric generators with a neutral grounded through an arc-suppression reactor, including in consolidated units with generators operating in parallel on a single low-voltage transformer winding.

Vainshtein, R. A., E-mail: vra@tpu.ru [Tomsk Polytechnical University (Russian Federation); Lapin, V. I. [ODU Sibiri (Integrated Dispatcher Control for Siberia), branch of JSC 'SO EES' (Russian Federation); Naumov, A. M.; Doronin, A. V. [JSC NPP 'EKRA' (Russian Federation); Yudin, S. M. [Tomsk Polytechnical University (Russian Federation)

2010-05-15

307

Optimal inflatable space towers of high height  

NASA Astrophysics Data System (ADS)

Author suggested, developed theory, and computed some projects of an optimal inflatable space tower of the heights some hundreds km. These towers can be used for tourism, scientist observation of space, Earth surface, Earth weather, Earth top atmosphere, and for radio, TV, communication transmissions. These towers can be used for launching of the space ships and Earth s atellites. The computed projects not expensive, do not request rockets. They need only in thin strong films composed from the artificial fibers and fabricated by a current industry. Towers can be built by a current technology. Towers can be explored (for tourism, communication, etc.) in a time of the construction process and give a profit, self- financing for further constriction. They can permanent increase their height. The tower design does not request a work at the high altitudes. All construction works will be making at the Earth surface. Author suggests the transport system for this tower of a high capability, which does not request a power energy issue. The small engine (only for a friction compensation) is located at the Earth surface. The tower is separated on sections and has a special protection of a case of a damage. It is considered also the problems of security, control, repair, etc. of the suggested towers. The author has also solved additional problems, which appear in these projects and which can look as difficult for the given proposal and current technology. The author is prepared to discuss the problems with serious organizations, which want to research and develop these projects.

Bolonkin, A.

308

Optimal Inflatable Space Towers of High Height  

NASA Astrophysics Data System (ADS)

Author provides theory and computations for building inflatable space towers up to a hundred km in height. These towers can be used for tourism; scientific observation of space, earth's surface, weather, top atmosphere, as well as for radio, television, and communication transmissions. These towers can also be used to launch space ships and Earth satellites. These projects are not expensive and do not require rockets. They require thin strong films composed from artificial fibers and fabricated by current industry. Towers can be built using present technology. Towers can be used (for tourism, communication, etc.) during the construction process and provide self-financing for further construction. The tower design does not require work at high altitudes; all construction can be done at the earth's surface. The transport system for this tower consists a small engine (used only for friction compensation) located at the earth's surface. The tower is separated into sections and has special protection mechanism in case of a damage. Problems involving security, control, repair, and stability of the proposed towers are addressed in subsequent publications. The author is prepared to discuss these and other problems with serious organizations desiring to research and develop these projects.

Bolonkin, Alexander

2002-01-01

309

Heat ad mass transfer in a cooling tower with special attention to the tower characteristic ratio  

Microsoft Academic Search

Explanation and calculation of the tower characteristic ratio for a cooling tower following a procedure from a paper. NOMENCLATURE T temperature (K) t temperature (°C) a surface area of water droplets per unit volume of tower (m2 m-3) K mass transfer coefficient (kg h-1 m-2 (kgw\\/kgda) -1 ) L water loading (kg h-l m-2) V active tower volume per unit

Michael Blocher

310

Monitoring-well network and sampling design for ground-water quality, Wind River Indian Reservation, Wyoming  

USGS Publications Warehouse

The Wind River Indian Reservation, located in parts of Fremont and Hot Springs Counties, Wyoming, has a total land area of more than 3,500 square miles. Ground water on the Wind River Indian Reservation is a valuable resource for Shoshone and Northern Arapahoe tribal members and others who live on the Reservation. There are many types of land uses on the Reservation that have the potential to affect the quality of ground-water resources. Urban areas, rural housing developments, agricultural lands, landfills, oil and natural gas fields, mining, and pipeline utility corridors all have the potential to affect ground-water quality. A cooperative study was developed between the U.S. Geological Survey and the Wind River Environmental Quality Commission to identify areas of the Reservation that have the highest potential for ground-water contamination and develop a comprehensive plan to monitor these areas. An arithmetic overlay model for the Wind River Indian Reservation was created using seven geographic information system data layers representing factors with varying potential to affect ground-water quality. The data layers used were: the National Land Cover Dataset, water well density, aquifer sensitivity, oil and natural gas fields and petroleum pipelines, sites with potential contaminant sources, sites that are known to have ground-water contamination, and National Pollutant Discharge Elimination System sites. A prioritization map for monitoring ground-water quality on the Reservation was created using the model. The prioritization map ranks the priority for monitoring ground-water quality in different areas of the Reservation as low, medium, or high. To help minimize bias in selecting sites for a monitoring well network, an automated stratified random site-selection approach was used to select 30 sites for ground-water quality monitoring within the high priority areas. In addition, the study also provided a sampling design for constituents to be monitored, sampling frequency, and a simple water-table level observation well network.

Mason, Jon P.; Sebree, Sonja K.; Quinn, Thomas L.

2005-01-01

311

COOLING TOWER PUMP HOUSE, TRA606. CONNECTION TO COOLING TOWER. PUMPHOUSE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

COOLING TOWER PUMP HOUSE, TRA-606. CONNECTION TO COOLING TOWER. PUMP-HOUSE FLOOR PLAN AND FOUNDATION PLANS. LAYOUT OF SIX COOLING TOWER UNITS. BLAW-KNOX 3150-807-2, 12/1950. INL INDEX NO. 53-0607-62-098-100671, REV. 1. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

312

Design and Construction of a Scaled Whirl Tower Facility  

NASA Astrophysics Data System (ADS)

Experimental development of helicopter rotors requires centrifugal testing before entry into a wind tunnel or flight test campaign. This centrifugal testing is performed on test rigs called whirl towers. These facilities are very rare, in fact there were none available in Canada at the time of writing this thesis, but they are very valuable experimental research tools. This thesis describes the design and construction of a whirl tower facility for the centrifugal testing of scaled helicopter rotors with actively controlled systems for reducing vibration. First, the trade-offs between the desired capabilities for the facility to be designed are reviewed, leading to the identification of a set of design requirements. Following this, various concepts for the drive system, frame, data acquisition, and safety infrastructure are proposed. From these, a final design is assembled, whose main advantage is its flexibility and robustness for developmental research. The whirl tower is capable of testing single or multi-bladed rotors (up to four blades), with blades between 1.0 and 1.6 m radius, up to 1,800 RPM frequency with no 'dead zones'. The whirl tower is equipped with a 60 HP, 575 V, AC motor, with flexible coupling and direct drive to the scaled rotor hub. The facility also features a digital telemetry system, slip rings for power and signal transmission for active control, interchangeable rotor heads with variable root distance, and a containment wall for protection from possible rotor blade failures. The manufacturing and construction of the facility, as well as its installation at the National Research Council in Ottawa, is described in detail.

Pickard, John Alexander

313

Wind profiler demonstration system  

NASA Technical Reports Server (NTRS)

The National Oceanic and Atmospheric Administration (NOAA) has started procurement of a 30-station demonstration network of Doppler radar wind profilers to be deployed in the central United States by 1989. The purposes of this demonstration network are: (1) to assess the impact of a large wind profiler network on meteorological forecasting; (2) to test wind profiler hardware designed specifically for commercial production and widespread deployment; and (3) to provide wind data for research programs involving weather phenomena in the central United States.

Chadwick, R. B.

1986-01-01

314

Vigiestrips : Toward a Paperless tower cab  

Microsoft Academic Search

This paper discusses the current status in the development of a modernized Human Machine interface (HMI) for Air Traffic Controllers (ATCO), which substitutes paper progress strips for an innovative touch input device system (Vigiestrips). After highlighting the cognitive use of current paper strips in towers, a previous article (see (1)) reported on the major requirements that information systems in towers

HCI Aero; Joël Garron; Jérôme Journet; Didier Pavet

315

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN FROM BELOW, SHOWING VALVE TOWER TO RIGHT. VIEW FACING NORTH - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream East Range, Wahiawa, Honolulu County, HI

316

DETAIL OF VALVE TOWER SHOWING SLUICE GATE ON EAST SIDE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL OF VALVE TOWER SHOWING SLUICE GATE ON EAST SIDE OF TOWER. VIEW FACING WEST - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower, Kalakoa Stream East Range, Wahiawa, Honolulu County, HI

317

Dynamic models of wind farms with fixed speed wind turbines  

Microsoft Academic Search

The increasing wind power penetration on power systems requires the development of adequate wind farms models for representing the dynamic behaviour of wind farms on power systems. The behaviour of a wind farm can be represented by a detailed model including the modelling of all wind turbines and the wind farm electrical network. But this detailed model presents a high

Luis M. Fernández; José Ramón Saenz; Francisco Jurado

2006-01-01

318

Cascading Kalman Observers of Structural Flexible and Wind States for Wind Turbine Control  

Microsoft Academic Search

We formulate novel observers of the structural flexible states of a wind turbine, as well as of the wind incident on its rotor. Stochastic filtering processes reconstruct on-line optimal estimates of the tower and blade states, by using readings from accelerometers and strain gages placed along the structural members. From these re- constructed states, another filtering process estimates the wind

C. L. Bottasso; A. Croce

319

Kinetic Space Towers and Launchers  

NASA Astrophysics Data System (ADS)

The paper discusses a new revolutionary method for access to outer space. A cable stands up vertically and pulls up its payload to space with a maximum force determined by its strength. From the ground the cable is allowed to rise up to the required altitude. After this, one can climb to an altitude by this cable or deliver to altitude a required load. The paper shows this is possible and does not infringe on the law of gravity. The article contains the theory of the method and the computations for four projects for towers that are 4, 75, 225 and 160,000 km in height. The first three projects use conventional artificial fiber widely produced by current industry, while the fourth project uses nanotubes made in scientific laboratories. The paper also shows in a fifth project how this idea can be used to launch a load at high altitude.

Bolonkin, A.

320

Augmented Reality Tower Technology Assessment  

NASA Technical Reports Server (NTRS)

Augmented Reality technology may help improve Air Traffic Control Tower efficiency and safety during low-visibility conditions. This paper presents the assessments of five off-duty controllers who shadow-controlled' with an augmented reality prototype in their own facility. Initial studies indicated unanimous agreement that this technology is potentially beneficial, though the prototype used in the study was not adequate for operational use. Some controllers agreed that augmented reality technology improved situational awareness, had potential to benefit clearance, control, and coordination tasks and duties and could be very useful for acquiring aircraft and weather information, particularly aircraft location, heading, and identification. The strongest objections to the prototype used in this study were directed at aircraft registration errors, unacceptable optical transparency, insufficient display performance in sunlight, inadequate representation of the static environment and insufficient symbology.

Reisman, Ronald J.; Brown, David M.

2009-01-01

321

Low level remote sensing: Orographic winds  

NASA Technical Reports Server (NTRS)

The orographic flow data set was obtained from a flight program to measure the influence of orographic features on turbulence momentum, heat, and moisture fluxes. The NASA B-57 aircraft instrumented with probes for measuring the three fluctuating wind speed components, temperature, and humidity was the primary measuring vehicle. Ancillary measurements were made with several ground-based sensors. These include the NOAA radar wind profilers, the Boulder wind network, the PROFS mesoscale surface network, the Boulder Atmospheric Observatory 300 m tower, special rawinsonde observations, and the NOAA/WPL Doppler lidar. The major objective of the flight program was to provide planetary boundary layer parameter information for new and current general circulation computer models. A numerical code, WINDER, based on a discrete element technique was run to numerically model the water tunnel simulated flow. Comparison of the analytical model with the experimental results is very good. Physical fluid dynamic principles embedded in the computational model and visual and hot wire anemometer measurements from the simulation are being rationalized to develop a physical understanding of the vortex flow. The results will be interpreted as they pertain to full scale atmospheric flows.

Frost, Walter

1989-01-01

322

VALVE TOWER FROM HIGH GROUND NEAR APPROACH BRIDGE. VIEW FACING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VALVE TOWER FROM HIGH GROUND NEAR APPROACH BRIDGE. VIEW FACING NORTHEAST - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower, Kalakoa Stream East Range, Wahiawa, Honolulu County, HI

323

Application of ceilometers to retrieve planetary boundary layer height near tall-tower sites  

NASA Astrophysics Data System (ADS)

Tall tower measurement sites can provide continuous records of various climate-relevant atmospheric gases like CO2, CH4, CO, N2O, or SF6 at different altitude levels. With the help of inverse transport models, the results can be used to determine sources and sinks of important greenhouse gases. Several tall tower sites with heights around 300 m have been established in Poland, Germany and France. Depending on the height of the tower and meteorological conditions, the different levels are influenced by air masses on a local to synoptic scale. A critical parameter for the analysis of the data is the planetary boundary layer height (PBL). If the top of the tower is still inside the PBL the measurements at the top level would be mostly influenced by local to regional sources and sinks. If the top is already in the free troposphere the measurements would be influenced by long-range transport. However, the PBL height cannot be derived from the tower measurements alone. Within the preparations for the Integrated Carbon Observing System (ICOS), several methods for determining PBL height near tall tower sites have been evaluated. During a campaign in France in October 2008, lidar systems, radio sondes as well as two different commercial ceilometers (Vaisala CL31 and Jenoptik CHM15k) were run side-by-side. One goal of the campaign was to find out if and how ceilometers could be used to retrieve PBL height operationally and if they should become part of future ICOS network sites.

Biavati, G.; Feist, D. G.; Heimann, M.

2009-04-01

324

Local vibration of transmission line towers due to flood flow. Technical report  

SciTech Connect

Local vibration of transmission line tower due to flood affects the lattices close to ground level, the lattices being slender. This is specially the case with broad based tangent towers for single conductor lines, since the stresses in the lattices are nominal and these have to be designed on the consideration of upper limit of slenderness ratio. Sustained flood flow can cause dynamic stresses resulting in yielding of the lattices ultimately leading to failure of the tower itself. Provision of intermediate supports for the lattices at suitable locations can bring down the amplitude of vibration and hence dynamic stresses. Interference with the vortex shedding by provision of wire winding or strakes, are also suitable steps to keep down the high dynamic stress due to flood flow.

Not Available

1982-05-01

325

Enhanced Control and Operation of DFIG-Based Wind Farms During Network Unbalance  

Microsoft Academic Search

This paper investigates the control and operation of doubly fed induction generator (DFIG)-based wind generation systems under unbalanced voltage conditions. DFIG system behaviors under unbalanced voltage are analyzed and different control targets are discussed. A new rotor current control strategy containing a main controller and an auxiliary controller is proposed. The main controller is implemented in the positive (dq)+ frame

Lie Xu

2008-01-01

326

Improved Control of DFIG Wind Turbines for Operation with Unbalanced Network Voltages  

Microsoft Academic Search

Many wind turbine generators (WTGs) are installed in remote, rural areas, where the power grids are usually weak, characterized by unbalanced voltage conditions. If the voltage unbalance is not taken into account in the control system, it will cause poor power quality and poor operating performance of the WTG systems. This paper proposes a novel control scheme to improve the

Wei Qiao; Ronald G. Harley

2008-01-01

327

Applying Time Series to Power Flow Analysis in Networks With High Wind Penetration  

Microsoft Academic Search

With high levels of variable renewable generation in distribution or transmission systems, the application of demand and generation time series to power flow analysis can be advantageous. Demand data are often available from historic measurements, while renewable generation such as wind turbine output may be recorded or can be derived from resource measurements over the corresponding period of time. Power

Thomas Boehme; A. Robin Wallace; Gareth P. Harrison

2007-01-01

328

Real-time simulation of BLDC-based wind turbine emulator using RT-LAB  

Microsoft Academic Search

A novel wind turbine emulator (WTE) based on a torque controlled Brushless DC (BLDC) motor is presented, which can emulate the steady-state and dynamic characteristics of an actual wind turbine. Variable wind speeds, turbine inertia and torque oscillation caused by tower shadow and wind shear are all considered in the construction of the actual wind turbine model and the torque

Honghao Guo; Bo Zhou; Jichen Li; Fangshun Cheng; Le Zhang

2009-01-01

329

Neural systems engaged by planning: a PET study of the Tower of London task  

Microsoft Academic Search

The functional anatomy of planning was investigated using the Tower of London task. Activation was observed in a distributed network of cortical areas incorporating prefrontal, cingulate, premotor, parietal and occipital cortices. Activation in corresponding areas has been observed in visuospatial working memory tasks with the exception of the rostral prefrontal cortex. This area may be identified with the executive components

S. C. Baker; R. D. Rogers; A. M. Owen; C. D. Frith; R. J. Dolan; R. S. J. Frackowiak; T. W. Robbins

1996-01-01

330

Plant Light Stress Tolerance across the New Mexico Elevation Gradient: Scaling from Leaf to Tower  

Microsoft Academic Search

Excess light is a major abiotic component of plant stress especially when combined with sustained periods of drought. Arid and semi-arid ecosystems are regularly exposed to sustained high light, low water conditions. A network of nine Eddy Covariance towers oriented along an elevation gradient in central New Mexico has been utilized to assess differences in light use efficiency and light

D. J. Krofcheck; D. Hanson; A. M. Fox; M. E. Litvak

2010-01-01

331

Prediction of Aerodynamic Coefficients for Wind Tunnel Data using a Genetic Algorithm Optimized Neural Network.  

National Technical Information Service (NTIS)

A fast, reliable way of predicting aerodynamic coefficients is produced using a neural network optimized by a genetic algorithm. Basic aerodynamic coefficients (e.g. lift, drag, pitching moment) are modelled as functions of angle of attack and Mach number...

T. Rajkumar C. Arragon J. Bardina R. Britten

2003-01-01

332

Alternative water treatment for cooling towers  

SciTech Connect

Problems commonly found in cooling towers include: calcium scale formation, corrosion, algae and bacterial growth. These problems can inhibit a cooling tower from operating at its most efficient capacity. An energy-saving, cost-efficient method to control each of these problems in tower water will ultimately benefit the owner as well as the environment. Supplemental ionic water purification was developed to overcome the disadvantages associates with a total chemical disinfection system. The concept of supplemental ionic water purification was developed in the early 1900s and later reviewed by NASA in the mid-1960`s. Only in the past seven years have biologists combined copper ions with chlorine to act as a bactericide. The findings have shown that metal compound ions (copper), when absorbed by bacteria, affect the organisms enzyme balance. This combination inhibits the organism`s reproduction and respiration capabilities. This technology has been applied to cooling tower operations as an alternative to a chemical-only regimen.

Wilsey, C.A. [Water Clear, Inc., Mound, MN (United States)

1997-04-01

333

New Traffic Control Tower-South Pole  

NSF Publications Database

... of safety for all personnel working within the program. The Special Initiative for Antarctic Safety ... green" in color while the new Tower would be "international orange and white". This color would be ...

334

Mathematical Modeling of Cooling-Tower Plumes.  

National Technical Information Service (NTIS)

The vast majority of mathematical models used to predict plume rise from natural-draft (NDCT) and mechanical-draft (MDCT) cooling towers employ the integral approach. The following significant areas of controversy exist in the theoretical development of s...

R. Carhart A. Policastro

1982-01-01

335

Performance Analysis of Mechanical Draft Cooling Tower.  

National Technical Information Service (NTIS)

Industrial processes use mechanical draft cooling towers (MDCT's) to dissipate waste heat by transferring heat from water to air via evaporative cooling, which causes air humidification. The Savannah River Site (SRS) has cross-flow and counter-current MDC...

A. Garrett J. Bollinger L. Koffman S. Lee

2009-01-01

336

Oil well rig with water tower  

SciTech Connect

An oil well rig having a flotatable hull and support legs which are lifted and supported by the floating hull for moving the oil well rig and moved down to engage the sea bottom and jack up or raise the hull above the water at an operating site for drilling or servicing a well or serving an offshore well platform. A water tower has pipes longitudinally mounted by brackets on each side on a beam and is mounted for vertical movement in a well in the hull. An elevator mechanism mounted in the hull is employed to raise and lower the water tower which has guide means fitting a guide portion of the well to provide guided vertical movement of the water tower. When the water tower is lowered, a pump at the bottom of the pipe pumps sea water through the pipe to machinery on the hull to meet the water requirements of the machinery.

Younes, D. T.

1984-09-18

337

Multistory transmission tower model for lightning surge analysis  

Microsoft Academic Search

Transmission towers have been modeled for lightning surge analysis based on the measurements on the towers alone. For an actual high voltage transmission tower, however, ground wires are equipped in many cases. This paper proposes a multistory transmission tower model to be used in the multi-conductor analysis by EMTP. The circuit parameters of the model are determined based on the

M. Ishii; T. Kawamura; T. Kouno; E. Ohsaki; K. Shiokawa; K. Murotani; T. Higuchi

1991-01-01

338

Urban Climatology Applied to the Deterioration of the Pisa Leaning Tower, Italy  

NASA Astrophysics Data System (ADS)

Among the peculiarities of the urban climatology, a relevant one concerns the interactions with monuments, which include stone weathering, deposition and removal of airborne pollutants. In order to know more about the case of the Pisa Leaning Tower, Italy, a field survey has been made for one year, measuring the microclimate interacting with the structure, the vertical temperature and humidity profiles, the Tower surface temperature at different locations and the concentration of particles in air. Also more general information was collected studying the meteorological parameters in the area of Pisa. The correlation between rainfalls and wind evidenced that the windborne droplets arrive from preferential directions, determined on the regional scale by the sea shore on the west (sea breeze) and the channelling operated by the valley of the Arno river on the west. The tilting of the Tower gives a natural shield to the southern part, which is hardly washed by rainfall. The complex balance between airborne particulate matter deposition, tower tilting, rainfall washout and surface runoff determines the pattern of the black crusts which disfigure the elegance of this historical building. The land and sea breezes transport air with different moisture content, and the urban heat island accentuates the mid day drop on relative humidity, determining condensation-evaporation cycles in the stone micropores. The urban climatology of Pisa and the interactions with the Leaning Tower are discussed in view of the conservation of this monument.

Camuffo, D.; Sturaro, G.; Valentino, A.

339

Soaring Towers: Building with Recycled Materials  

NSDL National Science Digital Library

In this activity, learners will build the highest tower they can out of recycled materials. As they work on this activity, they explore which shapes and sizes make good tower bases, which work well in the middle, and how to make sure the configuration is stable, even when some of the shapes are quite irregular. Available as a web page, downloadable pdf, and in Spanish.

Terc

2010-01-01

340

Grid-side converter control of DFIG wind turbines to enhance power quality of distribution network  

Microsoft Academic Search

A doubly fed induction generator wind turbine (DFIG-WT) with FACTS capabilities is presented. It is suggested to make use of the grid-side converter as a shunt active filter in order to support the grid with power factor correction as well as harmonic compensation. A vector control scheme is used to control the grid-side converter with a priority level feature to

E. Tremblay; A. Chandra; P. J. Lagace

2006-01-01

341

INL Wind Farm Project Description Document  

SciTech Connect

The INL Wind Farm project proposes to install a 20 MW to 40 MW wind farm on government property, consisting of approximately ten to twenty full-sized (80-meter hub height) towers with 2 MW turbines, and access roads. This includes identifying the optimal turbine locations, building access roads, and pouring the tower foundations in preparation for turbine installation. The project successfully identified a location on INL lands with commercially viable wind resources (i.e., greater than 11 mph sustained winds) for a 20 to 40 MW wind farm. Additionally, the proposed Wind Farm was evaluated against other General Plant Projects, General Purpose Capital Equipment projects, and Line Item Construction Projects at the INL to show the relative importance of the proposed Wind Farm project.

Gary Siefert

2009-07-01

342

INL Wind Farm Project Description Document.  

National Technical Information Service (NTIS)

The INL Wind Farm project proposes to install a 20 MW to 40 MW wind farm on government property, consisting of approximately ten to twenty full-sized (80-meter hub height) towers with 2 MW turbines, and access roads. This includes identifying the optimal ...

G. Siefert

2009-01-01

343

Wind turbine modeling using the bond graph  

Microsoft Academic Search

This paper addresses the problem of bond graph methodology as a graphical approach for modeling wind turbine systems. In this case, we consider the modeling of a wind turbine system with individual pitch control scheme and the interaction with tower motions. Two different bond graph models are presented, one complex and one simplified. Furthermore, the purpose of this paper is

Tore Bakka; Hamid Reza Karimi

2011-01-01

344

Wind turbine spoiler  

DOEpatents

An aerodynamic spoiler system for a vertical axis wind turbine includes spoilers on the blades initially stored near the rotor axis to minimize drag. A solenoid latch adjacent the central support tower releases the spoilers and centrifugal force causes the spoilers to move up the turbine blades away from the rotor axis, thereby producing a braking effect and actual slowing of the associated wind turbine, if desired. The spoiler system can also be used as an infinitely variable power control by regulated movement of the spoilers on the blades over the range between the undeployed and fully deployed positions. This is done by the use of a suitable powered reel and cable located at the rotor tower to move the spoilers.

Sullivan, William N. (Albuquerque, NM) [Albuquerque, NM

1985-01-01

345

Flicker contribution of a wind turbine in a stand-alone wind diesel system  

Microsoft Academic Search

To study the impact of aeroelastic aspects of a wind turbine (i.e. tower shadow, wind shear, turbulence, and mechanical vibrations) on the power quality of a wind-diesel system all electrical, mechanical and aerodynamic aspects of the wind turbine must be studied. Moreover, the contribution of the diesel-generator system and its controllers should be considered. This paper, describes how the aerodynamic

Roohollah Fadaeinedjad; Gerry Moschopoulos; Mehrdad Moallem

2008-01-01

346

Failure analysis on collapsed towers of overhead electrical lines in the region Münsterland (Germany) 2005  

Microsoft Academic Search

End of November 2005 strong south-west wind and heavy snowfall were predominant in the region Münsterland, north-western part of Germany. This led to accretion of a considerable quantity of wet snow to overhead electrical lines in form of snow rolls on the conductors. Eighty-two transmission towers failed catastrophically, most of them by buckling, however some by brittle fracture. As a

C. Klinger; M. Mehdianpour; D. Klingbeil; D. Bettge; R. Häcker; W. Baer

2011-01-01

347

Depolarization effect in signals scattered by wind turbines  

Microsoft Academic Search

Introduction: Th e increase in the number of wind farms as well as their larger sizes lead to an increase in the possibility of interference with nearby radiocommunication systems. As possible disturbances scattering as well as diffraction from the wind turbine structure are considered. The wind turbines that are being installed nowadays are composed of towers with a height of

I. Etayo; A. Satrustegui; M. Yabar; F. Falcone

2011-01-01

348

Black Students in "Ivory Towers."  

ERIC Educational Resources Information Center

Interviews with 50 black adult students in British universities revealed their experience of racism in curriculum and staffing. They constructed informal support networks for themselves and were skeptical about the legitimacy of institutional knowledge and their expectations of employment. Although colleges emphasize widening access…

Allen, Paul

1997-01-01

349

Network boundary origins of fast solar wind seen in the low transition region?  

NASA Astrophysics Data System (ADS)

We present a study of a high spatial resolution raster acquired on-disk with the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) grating spectrograph on SoHO (the Solar and Heliospheric Observatory) in a polar Coronal Hole (CH) region. We analyse two EUV emission lines, representing the properties of solar plasma in the low transition region (TR), O III 703.87 Å (maximum electron temperature, Te? 8× 104 K), as well as in the corona, Mg IX 706.02 Å (Te? 106 K). For Mg IX, we find that low CH intensities correspond to negative Doppler velocities (outflows) of ?5 km s-1. Along the quiet Sun (QS)/CH boundaries, the coronal plasma begins to be more red-shifted. A coronal bright point (BP) located within the CH is blue-shifted in the coronal line. In the TR line, the outer region of the BP is red-shifted at ?5 km s-1, but, towards its middle, the shift is around zero. The O III line, although it shows predominant downward motion of ?5.5 km s-1 in the CH and ?6 km s-1 in the QS, it also has blue-shifts arranged in a small-scale network pattern with average negative values of 3.5 km s-1 in CH and 3 km s-1 in the QS. The blue-shifts are caused either by plasma outflows of a few km s-1, or by transient events such as bi-directional jets which dislocate plasma to upward velocities even higher than 100 km s-1. The outflows originate predominantly from the intersection between the magnetic network and the inter-network cells (network boundaries). The bi-directional jets are found along the CH/QS boundaries, and, moreover, in locations where the plasma seen in the Mg IX line is blue-shifted, but very close to small red-shifted regions. Another interesting change in behaviour is observed at the QS/CH boundaries, in the O III line, where plasma from the network changes its velocity sign, becoming red-shifted. Our results constitute the lowest-in-altitude observed signature of plasma outflows from the chromospheric network boundaries inside a CH. We have derived this conclusion from direct correlation between Doppler velocity and the intensity of the O III 702.87 Åline.

Popescu, M. D.; Doyle, J. G.; Xia, L. D.

2004-07-01

350

The Drop Tower Bremen -An Overview  

NASA Astrophysics Data System (ADS)

The Center of Applied Space Technology and Microgravity (ZARM) was founded in 1985 as an institute of the University of Bremen, which focuses on research on gravitational and space-related phenomena. In 1988, the construction of ZARM`s drop tower began. Since its inau-guration in September 1990, the eye-catching Drop Tower Bremen with a height of 146m and its characteristic glass roof has become twice a landmark on the campus of the University of Bremen and the emblem of the technology park Bremen. As such an outstanding symbol of space science in Bremen the drop tower provides an european unique facility for experiments under conditions of high-quality weightlessness with residual gravitational accelerations in the microgravity regime. The period of maximum 4.74s of each freely falling experiment at the Drop Tower Bremen is only limited by the height of the drop tower vacuum tube, which was fully manufactured of steal and enclosed by an outer concrete shell. Thus, the pure free fall height of each microgravity drop experiment is approximately 110m. By using the later in-stalled catapult system established in 2004 ZARM`s short-term microgravity laboratory is able to nearly double the time of free fall. This world-wide inimitable capsule catapult system meets scientists` demand of extending the period of weightlessness. During the catapult operation the experiment capsule performs a vertical parabolic flight within the drop tower vacuum tube. In this way the time of microgravity can be extended to slightly over 9s. Either in the drop or in the catapult operation routine the repetition rates of microgravity experiments at ZARM`s drop tower facility are the same, generally up to 3 times per day. In comparison to orbital platforms the ground-based laboratory Drop Tower Bremen represents an economic alternative with a permanent access to weightlessness on earth. Moreover, the exceptional high quality of weightlessness in order of 1e-6 g (in the frequency range below 100Hz) demonstrates a perfect experimental environment for unperturbed investigations of scientific phenomena. Motivated by these prospects many national and international groups have initialized research programs taking advantage of this drop tower facility. In respect thereof the spectrum of research fields and technologies in space-related conditions can be continuously enhanced at ZARM. In the first of our two talks we will give you an overview about the inner structure of ZARM, as well as the service and the operation offered by the ZARM Drop Tower Operation and Service Company (ZARM FAB mbH). The ZARM FAB mbH owned by the State Government of Bremen is a public company maintaining the drop tower facility and supporting experimentalists in scientific and technical questions before, during and after their drop or catapult campaigns. In detail, we will present you important technical drop tower informations, our support and the idea, how you can proceed with your microgravity-related experiment including all your requirements to successfully accomplish an entire drop or catapult campaign. In summary, we will illustrate the complete procedure, how to drop or to catapult an experiment capsule at the Drop Tower Bremen.

von Kampen, Peter; Könemann, Thorben; Rath, Hans J.

351

Evaluation of Wind Profiler Data  

NASA Technical Reports Server (NTRS)

This report presents the Applied Meteorology Unit's evaluation of a "Hypersodar" wind profiler located on KSC adjacent to tower 412. The sodar data used for this evaluation were collected during two different periods in March 1999 and November 1998. The evaluation is performed by calculating sodar data availability as a function of height, and bias and Root Mean Square (RMS) differences of wind speed and direction between sodar and tower 313 observations at comparable heights. The RMS differences in wind speed and wind direction from sodar wind solution B at KSC range from 0.65 m s (exp. -1) - 2.04 m s (exp. -1) and 4.5 - 32.3 deg., respectively. Note that these RMS differences are not bias-corrected. The vendor claims that the accuracy of the wind measurements from the sodar is better than 0.5 m s (exp -1) in speed and 10 deg. in direction. The results of the evaluation described here suggest that such accuracy may be attainable though the data available for this comparison made it impossible to confirm the vendor's claims. The sodar was not aligned with true north and was separated by a distance of 3.5 km from tower 313 used for comparisons in this study.

Manobianco, John; Palmblad, Robert

1999-01-01

352

Cooling tower water conditioning study. [using ozone  

NASA Technical Reports Server (NTRS)

Successful elimination of cooling tower treatment chemicals was demonstrated. Three towers functioned for long periods of time with ozone as the only treatment for the water. The water in the systems was reused as much as 30 times (cycles of concentration) without deleterious effects to the heat exchangers. Actual system blow-down was eliminated and the only makeup water added was that required to replace the evaporation and mist entrainment losses. Minimum water savings alone are approximately 75.1 1/kg/year. Cost estimates indicate that a savings of 55 percent was obtained on the systems using ozone. A major problem experienced in the use of ozone for cooling tower applications was the difficulty of accurate concentration measurements. The ability to control the operational characteristics relies on easily and accurately determined concentration levels. Present methods of detection are subject to inaccuracies because of interfering materials and the rapid destruction of the ozone.

Humphrey, M. F.; French, K. R.

1979-01-01

353

Comparison of upwind and downwind rotor operation of the DOE\\/NASA 100kW MOD0 wind turbine  

Microsoft Academic Search

Tests were conducted on a 38m diameter horizontal axis wind turbine, which had first a rotor downwind of the supporting truss tower and then upwind of the tower. Aside from the placement of the rotor and the direction of rotation of the drive train, the wind turbine was identical for both tests. Three aspects of the test results are compared:

J. C. Glasgow; D. R. Miller; R. D. Corrigan

1981-01-01

354

Characteristics of Winter Lightning that Occurred on a Windmill and its Lightning Protection Tower  

NASA Astrophysics Data System (ADS)

We have obtained the electric current, electric field change, and optical image data or several tens of lightning that hit on a wind turbine and its lightning-protection tower during the past6 non-stop winter seasons from 2005 to 2010. By analyzing the data, we found that the upward lightning hitting on the high structures can be classified into self-initiated and other-triggered types according to whether there is a discharge activity prior to the upward lightning. We also found that although other-triggered upward lightning can start at a relatively lower wind speed, self-initiated upward lightning always started either from the stationary tower under a larger wind speed or from a rotating wind turbine blade. It appears that the wind and by inference the corona discharge shielding do have considerable effect in the initiation of an upward leader. Regarding the initial progression of a positive leader, we found a systematic difference in the speeds of the leaders from the structures that have remarkably different heights. Finally, we discussed the pulse discharges observed in the very initial stages of positive upward leaders and also how to forecast direct strike of upward lightning.

Takagi, Nobuyuki; Wang, Daohong

355

Characteristics of Winter Lightning that Occurred on a Windmill and its Lightning Protection Tower in Japan  

NASA Astrophysics Data System (ADS)

We have observed lightning that struck a wind turbine and its neighboring lightning-protection tower during the past six winter seasons (2005 to 2010) using various lightning observation instruments. Our results show that the upward lightning from high structures can be classified into self-initiated and other-triggered types according to whether there is a discharge activity prior to the upward lightning. Furthermore, we found that although other-triggered upward lightning can start at a relatively low wind speed, self-initiated upward lightning always started either from the stationary tower under a larger wind speeds or from a rotating wind turbine blade. It appears that the wind does have considerable effect in assisting the initiation of an upward leader. In addition, we found that the self-initiated upward positive leaders from structures with different effective heights exhibited remarkably different initial speeds. Higher structures tend to initiate faster upward leaders. Finally, we discussed the pulse discharges observed in the very initial stages of positive upward leaders and how to protect structures from upward lightning as well.

Wang, Daohong; Takagi, Nobuyuki

356

Wind shear climatology for large wind turbine generators  

SciTech Connect

Climatological wind shear analyses relevant to the design and operation of multimegawatt wind turbines are provided. Insight is provided for relating the wind experienced by a rotating blade in a shear flow to the analysis results. A simple analysis of the wind experienced by a rotating blade for three types of wind shear profiles under steady-state conditions is presented in graphical form. Comparisons of the magnitude and frequency of the variations in 1) the wind sensed by a single blade element, 2) the sum, and 3) the difference of the winds sensed by opposite blade elements show strong sensitivity to profile shape. These three items represent forcing functions that can be related to 1) flatwise bending moment, 2) torque on the shaft, and 3) teeter angle. A computer model was constructed to simulate rotational sampling of 10-s sampled winds from a tall tower for three different types of large wind turbines. Time series produced by the model indicated that the forcing functions on a rotating blade vary according to the shear profile encountered during each revolution as opposed to a profile derived from average wind conditions, e.g., hourly average winds. An analysis scheme was developed to establish a climatology of wind shear profiles derived from 10-s sampled winds and hourly average winds measured over a one-year period at several levels on a tall tower. Because of the sensitivity of the forcing function variability to profile shape, the analyses performed and presented are in the form of joint frequency distributions of velocity differences of the the top-to-hub versus the hub-to-bottom portion of disks of rotation for the three turbine configurations.

Elliott, D.L.; Wendell, L.L.; Heflick, S.K.

1982-10-01

357

Recent results from data analysis of dynamic stall on wind turbine blades  

Microsoft Academic Search

Wind turbines are subjected to dynamic loading from a variety of different sources. Wind shear and turbulence cause time-varying inflow that results in unsteady airloads. Tower shadow, upwind turbine wakes, and yaw angles also introduce unsteady inflow to wind turbine rotors. Wind turbine designers must predict these loads accurately in order to adequately design blades, hubs, and the remaining support

C. P. Butterfield; D. Simms; S. Huyer

1992-01-01

358

Signal analysis and modeling of wind turbine clutter in weather radars  

Microsoft Academic Search

Lately, the continuing expansion of wind energy industry has led to the installation of several wind farms which are often in the vicinity of the weather radars. This is a source of growing concern for the weather radar community since wind turbines interfere with the normal operation of the weather radars. The wind turbine tower can drive the receivers into

Kumar Vijay Mishra; V. Chandrasekar

2010-01-01

359

Sliding mode control of wind energy systems with DOIG-power efficiency and torsional dynamics optimization  

Microsoft Academic Search

Wind turbines with double output induction generators can operate at variable speed permitting conversion efficiency maximization over a wide range of wind velocities. However, random wind fluctuations, wind shear and tower shadow, may excite the oscillation mode of the mechanical system, producing large torque ripple. Consequently, damage to drive train components and power quality problems may occur. In this paper,

H. De Battista; P. F. Puleston; R. J. Mantz; C. F. Christiansen

2000-01-01

360

Aerodynamic response analysis of wind turbines  

Microsoft Academic Search

Wind energy has received increasing attention in the same way as energy crisis and environmental deterioration. The aerodynamic\\u000a response of wind turbines is the major problem in wind turbine design. Blade element momentum theory was used to study the\\u000a aerodynamic thrusts of the blades on the tower. Iterative solutions were used to calculate the axial flow induction factor\\u000a for each

Jing Li; Jianyun Chen; Xiaobo Chen

2011-01-01

361

Wind Climate Analyses for SRTC's Central Climatology Site  

SciTech Connect

This report was written to present climatological summaries of the wind data at the Central Climatology (CC) tower in a convenient format and to point out some features of the wind speed and direction that have not been widely appreciated in the past. Short-term (two-week) wind roses provide a means to demonstrate the temporal and spatial relationships that wind speed and direction undergo using a ten-year database from the CC tower. These relationships are best demonstrated by examining the figures provided in this report or looking at loops of computer-generated images provided by the authors.

Weber, A.H.

2003-06-23

362

Investigations of the Tornado Wind-Energy System. Final report, September 1978April 1980  

Microsoft Academic Search

Tornado-type Wind Energy Systems (TWES) use the core of a vortex in a hollow tower to provide a low pressure exhaust reservoir for a wind turbine. Wind tunnel data are presented, and previous and planned test programs are described, including the evolution of tower design from the spiral-cross-sectional design through the passive omnidirectional design to the fixed-vane omnidirectional design. A

Yen

1980-01-01

363

2. Detail of tower foundation with lightning transfer wire, southeast ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Detail of tower foundation with lightning transfer wire, southeast corner - Cold Mountain Fire Lookout Station, Lookout Tower, Krassel District, Frank Church River of No Return Wilderness, Dixie, Idaho County, ID

364

View of the southwest guard tower, cell blocks seven and ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of the southwest guard tower, cell blocks seven and eight, administration building west tower, and Fairmount Avenue, looking from the administration building facing west - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

365

View from southwest to northeast of cooling towers for perimeter ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View from southwest to northeast of cooling towers for perimeter acquisition radar building and PAR power plant - Stanley R. Mickelsen Safeguard Complex, Cooling Tower, In Limited Access Area, between Service Roads D & A, Nekoma, Cavalier County, ND

366

North and west sides of the cooling tower, utility building ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

North and west sides of the cooling tower, utility building (building 2606) is in the background at right - March Air Force Base, Strategic Air Command, Cooling Tower, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

367

Project Plan: Tower Automated Ground Surveillance System Development Program.  

National Technical Information Service (NTIS)

The Tower Automated Ground Surveillance System (TAGS) represents an important step in providing automation support for air traffic controllers in the tower cab. During FY-1978 the objective of the TAGS activity is to perform the necessary analyses and fea...

M. E. Perie

1978-01-01

368

29. Photocopy of 1921 photograph. Glass Negative Box IX, Tower ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. Photocopy of 1921 photograph. Glass Negative Box IX, Tower Grove, Missouri Botanical Garden. ITALIAN GARDEN AND NEW PALM HOUSE (DEMOLISHED), LOOKING NORTHEAST - Missouri Botanical Garden, 2345 Tower Grove Avenue, Saint Louis, Independent City, MO

369

View of EPA Farm metal weather tower, facing east, showing ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of EPA Farm metal weather tower, facing east, showing thirty-acre irrigated field - Nevada Test Site, Environmental Protection Agency Farm, Weather Tower, Area 15, Yucca Flat, 10-2 Road near Circle Road, Mercury, Nye County, NV

370

39. View from top of Brooklyn Tower looking SW at ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

39. View from top of Brooklyn Tower looking SW at tower cornice, main cable and stay cables. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York, New York County, NY

371

10. View west along carillon tower axis from base of ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. View west along carillon tower axis from base of tower to gates in western estate wall at SR 141 - A. I. Du Pont Estate, Junction of State Route 141 & Rockland Road, Wilmington, New Castle County, DE

372

TOWER SECOND FLOOR INTERIOR, LOOKING WEST, SHOWING OVERHEAD TRACK DIAGRAM, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TOWER SECOND FLOOR INTERIOR, LOOKING WEST, SHOWING OVERHEAD TRACK DIAGRAM, OPERATING LEVERS (BEING PULLED BY OPERATOR TOM HARTMAN), AND AUXILIARY TRACK DIAGRAM ABOVE DESK AT LEFT. - Baltimore & Ohio Railroad, Z Tower, State Route 46, Keyser, Mineral County, WV

373

1. General view of crossing gate tower, taken in 1916 ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. General view of crossing gate tower, taken in 1916 (courtesy of Erie Railroad Company) (photocopy) - Erie Railway, Crossing Gate Tower, West side of Lincoln Street, 100 feet South of Concord Street, Union City, Erie County, PA

374

OVERVIEW OF VALVE TOWER FROM EASTERN SIDE OF BASIN SHOWING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OVERVIEW OF VALVE TOWER FROM EASTERN SIDE OF BASIN SHOWING BRIDGE SUPPORTS ON HILLTOP. VIEW FACING WEST - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower, Kalakoa Stream East Range, Wahiawa, Honolulu County, HI

375

OVERVIEW OF VALVE TOWER FROM NORTHERN SIDE OF BASIN. VIEW ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OVERVIEW OF VALVE TOWER FROM NORTHERN SIDE OF BASIN. VIEW FACING SOUTHWEST - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower, Kalakoa Stream East Range, Wahiawa, Honolulu County, HI

376

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN FROM ENTRY. VIEW FACING NORTHWEST - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream East Range, Wahiawa, Honolulu County, HI

377

2. Light tower and keeper's house, view southwest, north northeast ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Light tower and keeper's house, view southwest, north northeast side of tower, northeast and northwest sides of keeper's house - Wood Island Light Station, East end of Wood Island, at mouth of Soo River, Biddeford Pool, York County, ME

378

1. Keeper's house and light tower, view north northeast, southwest ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Keeper's house and light tower, view north northeast, southwest and southeast sides of house, northwest and southwest sides of tower - Wood Island Light Station, East end of Wood Island, at mouth of Soo River, Biddeford Pool, York County, ME

379

View uphill of single chair lift, tower 15 in foreground, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View uphill of single chair lift, tower 15 in foreground, TOWERS 16 and 17 in the distance, LOOKING SOUTH. - Mad River Glen, Single Chair Ski Lift, 62 Mad River Glen Resort Road, Fayston, Washington County, VT

380

VIEW FROM DIVE TOWER CONFERENCE ROOM FACING NORTH (FIRST FLIGHT ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW FROM DIVE TOWER CONFERENCE ROOM FACING NORTH (FIRST FLIGHT OF STAIRS) - U.S. Naval Base, Pearl Harbor, Submarine Dive Tower, Intersection of Clark & Morton Streets, Pearl City, Honolulu County, HI

381

TOWER S389, MAGAZINES IN BACKGROUND. Naval Magazine Lualualei, West ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TOWER S389, MAGAZINES IN BACKGROUND. - Naval Magazine Lualualei, West Loch Branch, Guard-Watch Tower Type, Near A Avenue between Fourth & Sixth Streets, Ninth Street & D Avenue intersection, & F Avenue, Pearl City, Honolulu County, HI

382

TOWER S389, WITH POLE. MAGAZINES IN BACKGROUND. Naval Magazine ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TOWER S389, WITH POLE. MAGAZINES IN BACKGROUND. - Naval Magazine Lualualei, West Loch Branch, Guard-Watch Tower Type, Near A Avenue between Fourth & Sixth Streets, Ninth Street & D Avenue intersection, & F Avenue, Pearl City, Honolulu County, HI

383

4. Gate tower and access bridge, showing trash rack, with ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Gate tower and access bridge, showing trash rack, with lake level drawn down. View to northeast. - Keechelus Dam, Outlet Tower, Yakim River, 10 miles northwest of Easton, Easton, Kittitas County, WA

384

26. Evening view of concrete mixing plant, concrete placement tower, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. Evening view of concrete mixing plant, concrete placement tower, cableway tower, power line and derrick. Photographer unknown, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

385

Optimal Inflatable Space Towers with 3 - 100 km Height.  

National Technical Information Service (NTIS)

Theory and computations are provided for building inflatable space towers up to one hundred kilometers in height. These towers can be used for tourism, scientific observation of space, observation of the Earth's surface, weather and upper atmosphere, and ...

A. Bolonkin

2003-01-01

386

Reconciling Latent and Sensible Energy Fluxes with Footprints in a Heterogeneous Landscape at an Urban-suburban Tower near Baltimore, Maryland  

NASA Astrophysics Data System (ADS)

Measurements of eddy-fluxes in an urban-suburban landscape may create technical difficulties as latent and sensible energy fluxes in the tower’s footprint are non-uniform. In an earlier study, we have found that the average vegetation cover surrounding the Cub Hill tower was 64 %; ranging from 46 to 77 % among 8 wind directions. We measured latent and sensible energy fluxes using a closed-path eddy-covariance system in the Cub Hill tower near Baltimore, Maryland. Half-hourly values of latent and sensible energy fluxes were stratified according to 24 15-degree bins of wind direction in each of the 16-day compositing periods for Normalized Difference Vegetation Index (NDVI) during 3 years of study (2004 to 2006). We used the daytime latent and sensible energy fluxes in the multivariate regression analyses to model fluxes of water vapor or evapotranspiration (ET) and sensible heat (H) as functions of micrometeorological variables (net radiation, temperature, relative humidity, wind speed, and soil moisture), NDVI, and land cover. Empirical models are developed at 16-day intervals for each of the 24 bins of wind direction to establish the relationships between energy fluxes (i.e., latent and sensible) and footprints (i.e., micrometeorology, NDVI, and land cover) around the Cub Hill tower.

Saliendra, N. Z.; Hom, J. L.; Pouyat, R. V.; Nowak, D.; Heisler, G. M.; Petterson, M.; Yesilonis, I.; Crawford, B.; Grimmond, S.

2009-12-01

387

Update on the Purdue University 2-second Drop Tower  

NASA Astrophysics Data System (ADS)

A small drop tower of approximately one second drop duration was built in the School of Aero-nautics and Astronautics at Purdue University beginning in 1998 and operated until summer 2007. This inexpensive tower in an old airplane hanger, was built largely by Yongkang Chen, now a Research Professor at Portland State University in Oregon, USA. In about 7 years of operations, the tower generated sufficient science results for Chen's PhD thesis[1] (summarized in three AIAA Journal papers[2-4]), Fitzpatrick's MS thesis[5], two industry projects for since-canceled advanced rodent habitats for ISS, and one project for NASA Marshall. In addition to the science use, Purdue undergraduate students designed, built, and performed simpler fluids experiments for their own career advancement, including a novel investigation of the impact of imperfect repeatability of initial conditions on a zero-g fluids experiment. The tower was also used for outreach to school children. It is most satisfying that Chen's PhD research in this small tower, and subsequent discussions and interactions, helped Weislogel to propose the two Vane Gap tests in his highly successful Capillary Fluids Experiment (CFE) in the International Space Station in 2006 and 2007[6]. Chen as been involved in the remodeling of these two Vane Gap cylinders for subsequent re-launch to ISS for a second round of experiments expected in 2010 and 2011. In August 2007 the School of Aeronautics and Astronautics at Purdue University moved into the new Neil Armstrong Hall of Engineering and construction on a new 2-second drop tower began. A vertical shaft of nearly 23 meters was designed into the building. An approximately 80 m2 general-use fluids lab is at the top level, and a small access room of approximately 9 m2 is at the bottom. However, construction of the new $57M building created only the space for the science facility, not the science facility itself. The science facility is under construction and this paper presents an update on progress for the micro-gravity community. The most noticeable current activity is testing of the air-bag decelerator. The tower is one that will use a free-falling experiment inside of a drag shield to avoid most aerodynamic drag. The airbag is designed from experiences of others yet the small, triangular room in which the tower terminates imposes challenges. The airbag is approximately 1.5m diameter and 1.5m tall. Initial testing led to a desire to increase vent area, and just this week the bag has returned from the shop that was modifying it. On-board computer, battery packs, lighting, and cameras have been acquired. Thanks to Lockheed Martin, one camera is 500 frames per second with 1.3 million 12-bit gray scale pixels per frame. The Spincraft company donated steel hemisphere-cylinders to serve as the nose of the drag shield. Wind tunnel and CFD modeling of the drag shield has been performed by Purdue undergraduate aerospace students. Currently the drag shield structure and experiment package structure are being design and analyzed. The experiment volume is approximately a cylinder 0.45m diameter and 0.6m tall. Tower operation is intended to commence in fall 2010 with inert package drops at full mass and full height. Developing the operations procedures, especially operational safety, are the goals of this work. First science is then expected in the winter. References 1. Y. Chen, "A Study of Capillary Flow in a Vane-wall Gap in Zero Gravity," Ph.D. thesis, School of Aeronautics and Astronautics, Purdue University. August 2003. 2. Y. Chen and S. H. Collicott, "Investigation of the Symmetric Wetting of a Vane-Wall Gap in Propellant Tanks," AIAA Journal, 42, No. 2, pp. 305-314, February 2004. 3. Y. Chen, and S. H. Collicott, "Experimental Study on the Capillary Flow in a Vane-Wall Gap Geometry," AIAA Journal, 43, No. 11, pp. 2395-2403, November, 2005. 4. Y. Chen and S. H. Collicott, "Study of Wetting in an Asymmetrical Vane-Wall Gap in Propellant Tanks," AIAA Journal, 44, 4, pp. 859-867, April 2006. 5. S. L. F

Collicott, Steven

388

Analysis of airborne Doppler lidar, Doppler radar and tall tower measurements of atmospheric flows in quiescent and stormy weather  

NASA Technical Reports Server (NTRS)

The first experiment to combine airborne Doppler Lidar and ground-based dual Doppler Radar measurements of wind to detail the lower tropospheric flows in quiescent and stormy weather was conducted in central Oklahoma during four days in June-July 1981. Data from these unique remote sensing instruments, coupled with data from conventional in-situ facilities, i.e., 500-m meteorological tower, rawinsonde, and surface based sensors, were analyzed to enhance understanding of wind, waves and turbulence. The purposes of the study were to: (1) compare winds mapped by ground-based dual Doppler radars, airborne Doppler lidar, and anemometers on a tower; (2) compare measured atmospheric boundary layer flow with flows predicted by theoretical models; (3) investigate the kinematic structure of air mass boundaries that precede the development of severe storms; and (4) study the kinematic structure of thunderstorm phenomena (downdrafts, gust fronts, etc.) that produce wind shear and turbulence hazardous to aircraft operations. The report consists of three parts: Part 1, Intercomparison of Wind Data from Airborne Lidar, Ground-Based Radars and Instrumented 444 m Tower; Part 2, The Structure of the Convective Atmospheric Boundary Layer as Revealed by Lidar and Doppler Radars; and Part 3, Doppler Lidar Observations in Thunderstorm Environments.

Bluestein, H. B.; Doviak, R. J.; Eilts, M. D.; Mccaul, E. W.; Rabin, R.; Sundara-Rajan, A.; Zrnic, D. S.

1986-01-01

389

Queensland University of Technology Drop Tower Facility  

NASA Astrophysics Data System (ADS)

The Queensland University of Technology (QUT) Drop Tower Facility provides access to an inexpensive high quality reduced gravity test environment. This facility is available to and has been used by number of nationally and internationally based organisations, along with researchers from QUT, for scientific and industry related research. The drop tower, located in Brisbane, Australia, allows 2.0 seconds of high quality reduced gravity (˜0.001 g). The cylindrical drop package has a maximum rating of 200 kg with dimensions of 0.8 m diameter and 0.9 m high, and experiences a maximum deceleration of ˜30 g. Current research projects being carried out at the QUT Drop Tower Facility include research in the areas of self-propagating high-temperature synthesis of materials, combustion and fire safety, flammability of metals, characterisation of combustion products, and sol-gel nanomaterials. Keywords: Reduced gravity, microgravity, drop tower, zero gravity, low gravity, combustion, combustion products, nanomaterials, sol-gel, flammability, high temperature synthesis.

Plagens, Owen; Hales, Matthew; Castillo, Martin; Steinberg, Theodore

2012-07-01

390

History and Mathematics: Tower of Hanoi  

NSDL National Science Digital Library

In this activity, students will Investigate the history and rules of the Tower of Hanoi game, and attempt to solve the puzzle with various numbers of variables. Then they will complete a table recording the number of moves, and use it to determine a rule for the minimum number of moves.

2010-01-01

391

The Tower and Glass Marbles Problem  

ERIC Educational Resources Information Center

The Catseye Marble company tests the strength of its marbles by dropping them from various levels of their office tower, to find the highest floor from which a marble will not break. We find the smallest number of drops required and from which floor each drop should be made. We also find out how these answers change if a restriction is placed on…

Denman, Richard T.; Hailey, David; Rothenberg, Michael

2010-01-01

392

The Legacy of the Texas Tower Sniper  

ERIC Educational Resources Information Center

In this article, the author relates the incident that happened at the University of Texas to the tragedy that took place at Virginia Tech. On August 1, 1966, Charles Joseph Whitman ascended the University of Texas Tower, in Austin, and in 96 minutes fired 150 high-powered rounds of ammunition down upon an unsuspecting university family. The…

Lavergne, Gary

2007-01-01

393

WET/DRY COOLING TOWER TEST MODULE  

EPA Science Inventory

The report gives results of an evaluation of the engineering performance of a single-cell wet/dry cooling tower (about 25 MW) in an 18-month field test at San Bernardino, CA. Test objectives included determination of the water conservation and operating characteristics, and verif...

394

Analytical and experimental study on surge response of transmission tower  

Microsoft Academic Search

Summary form only given as follows. This paper describes analytical and experimental studies on tower surge response, including effects of return stroke current. Such effects have been ignored in previous lightning surge analyses of transmission towers. A new method for calculating transmission tower surge response including the effects of return stroke current is proposed. The proposed method is based on

H. Motoyama; H. Matsubara

2000-01-01

395

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWERS THREE AND FOUR ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL VIEW OF AERIAL TRAM SUPPORT TOWERS THREE AND FOUR WITH TOWERS FIVE AND SIX IN THE DISTANCE, LOOKING NORTHEAST. THE TWO INTACT CABLES RUNNING ALONG TOP OF THE TOWERS ARE FIXED. WHILE THE MOVING CABLE IS LYING SLACK ON THE GROUND. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

396

38. View from top of Brooklyn Tower showing man walking ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

38. View from top of Brooklyn Tower showing man walking up main cable, stay cables radiating from top of tower and tower cornice. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York, New York County, NY

397

Exxon's guyed tower nears load-out date  

Microsoft Academic Search

Exxon's Lena guyed tower, installed in 1,000ft. water in the Gulf of Mexico, is discussed. The Lena tower is designed to move in response to wave forces rather than resist them rigidly, as is the case with conventional platforms. Selection of tower components to satisfy requirements resulted in a complex geometry which presented design challenges. Buoyancy will serve as a

M. S. Glasscock; L. D. Finn

1983-01-01

398

Solar Power Tower Design Basis Document, Revision 0.  

National Technical Information Service (NTIS)

This report contains the design basis for a generic molten-salt solar power tower. A solar power tower uses a field of tracking mirrors (heliostats) that redirect sunlight on to a centrally located receiver mounted on top a tower, which absorbs the concen...

Zavoico

2001-01-01

399

8. VIEW OF THE EAST BASE CONNECTION OF ANTENNA TOWER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. VIEW OF THE EAST BASE CONNECTION OF ANTENNA TOWER S-111 FACING NORTHEAST. BUILDING 1 AND ANTENNA TOWER S-110 IN THE BACKGROUND. - U.S. Naval Base, Pearl Harbor, Lualualei Radio Transmitter, Edison & Tower Drives, Pearl City, Honolulu County, HI

400

Upgrading of transmission towers using a diaphragm bracing system  

Microsoft Academic Search

Many older transmission towers are designed based on tension-only bracing systems with slender diagonal members. However, the increased demand in power supply and changing global weather patterns mean that these towers require upgrading to carry the resultant heavier loading. The failure of a single tower can rapidly propagate along the line and result in severe damage that costs many millions

F. Albermani; M. Mahendran; S. Kitipornchai

2004-01-01

401

An automatic and effective approach in identifying tower cranes  

NASA Astrophysics Data System (ADS)

A method which can distinguish tower cranes from other objects in an image is proposed in this paper. It synthesizes the advantages of both morphological theory and geometrical characters to identify tower cranes accurately. The algorithm uses morphological theory to remove noise and segment images. Moreover, geometrical characters are adopted to extract tower cranes with thresholds. To test the algorithm's practical applicability, we apply it to another image to check the result. The experiments show that the approach can locate the position of tower cranes precisely and calculate the number of cranes at 100% accuracy rate. It can be applied to identifying tower cranes in small regions.

Yu, Bo; Niu, Zheng; Wang, Li; Liu, Yaqi

2012-04-01

402

Science and Technical Considerations for Wind Farm Siting  

NSDL National Science Digital Library

This instructional module was created at the 2009 ATEEC Fellows Institute on Wind Power. The following sections are provided: An introduction to wind power classes, Offshore turbine tower foundations, Wind speed lab, Wind shear project, Turbulence and links to supporting resources. The classroom lessons include student worksheets. The entire guide may be downloaded in PDF file format. This resource is free to download. Users must first create a login with ATEEC's website to access the file.

2013-06-21

403

A review of the SERI wind energy innovative systems program  

Microsoft Academic Search

Features of innovative wind energy conversion systems evaluated and\\/or tested at the Solar Energy Research Institute are reviewed. Cost, performance, and engineering data were acquired for the machines, along with proof-of-concept demonstrations. Machines which were examined included a straight-bladed vertical axis wind turbine with circulation controlled airfoils, the Grumman tornado wind energy tower with louvers, a wind-powered charged aerosol generator

I. E. Vas; P. South

1980-01-01

404

Characterising the effect of a variety of surface roughness on boundary layer wind and dynamics within the scanning Doppler lidar network in Finland  

NASA Astrophysics Data System (ADS)

Aerosol particle and trace gas atmospheric content is controlled by natural and anthropological emissions. However, further dispersion in the atmosphere is driven by wind and dynamic mixing. Atmospheric surface and boundary layer dynamics have direct and indirect effects on weather, air quality and processes affecting climate (e.g. gas exchange between ecosystem and atmosphere). In addition to the amount of solar energy and prevailing meteorological condition, the surface topography has a strong influence on the close to surface wind field and turbulence, particularly in urban areas (e.g. Barlow and Coceal, 2009). In order to characterise the effect of forest, urban and coastal surfaces on boundary layer wind and mixing, we have utilised the Finnish Doppler lidar network (Hirsikko et al., 2013). The network consists of five 1.5 ?m Doppler lidars (HALO Photonics, Pearson et al., 2009), of which four are capable of full hemispheric scanning and are located at Helsinki (60.12°N, 25.58°E, 45 m asl.), Utö island (59.47°N, 21.23°E, 8 m asl.), SMEAR II at Hyytiälä (61.50°N, 24.17°E, 181 m asl.) and Kuopio (62.44°N, 27.32°E, 190 m asl.). The fifth lidar at Sodankylä (67.37°N, 26.63°E, 171 m asl.) is a new model designed for the Arctic environment with no external moving parts, but still retains limited scan capability. Investigation of boundary layer wind and mixing condition can now be extended beyond vertical profiles of horizontal wind, and dissipation rate of turbulent kinetic energy (O'Connor et al., 2010) throughout the boundary layer. We have applied custom designed scanning routines for 3D-observation of the wind fields and simultaneous aerosol particle distribution continuously for over one year at Helsinki and Utö, and began similar scanning routines at Kuopio and Hyytiälä in spring 2013. In this long term project, our aims are to 1) characterise the effect of the land-sea interface and the urban environment on the wind and its turbulent nature near the surface (< 200 m above the ground) observed at our four measurement sites, 2) characterise aerosol particle spatial and temporal distribution, and 3) deploy obtained results in air quality monitoring purpose and weather models. Here, we focus on wind field characterisation. The effect of sea, land and certain buildings were clear and evident in our wind data. The results compare favourably with in-situ point observations available indicating the applicability of the 3D-measurement routines and subsequent data analysis. Acknowledgements This research was supported by funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant 262254, and by the Maj and Tor Nessling foundation (Dispersion of air pollution in the boundary layer - new approach with scanning Doppler lidars). References Barlow J. and Coceal, O.: A review of urban roughness sublayer turbulence, Met Office Tech. Rep., Exeter, p. 68, 2009. Hirsikko, A., et al.: Observing aerosol particles, clouds and boundary layer wind: a new remote sensing network in Finland, in preparation for Atmos. Meas. Tech., 2013. O'Connor, E.J., Illingworth, A.J., Brooks, I.M., Westbrook, C.D., Hogan, R.J., Davies, F. and Brooks, B.J.: A Method for Estimating the Turbulent Kinetic Energy Dissipation Rate from a Vertically Pointing Doppler Lidar, and Independent Evaluation from Balloon-Borne In Situ Measurements, J. Atmos. Ocean. Technol., 27, 1652-1664, 2010. Pearson, G., Davies, F., and Collier, C.: An Analysis of the Performance of the UFAM Pulsed Doppler Lidar for Observing the Boundary Layer, J. Atmos. Ocean. Tech., 26, 240-250, 2009.

Hirsikko, Anne; O'Connor, Ewan J.; Wood, Curtis R.; Vakkari, Ville

2013-04-01

405

Episodic Magnetic Tower Jets in Laboratory Experiments  

NASA Astrophysics Data System (ADS)

Results from laboratory astrophysics experiments showing the formation of episodic plasma jets will be presented. The jets are highly supersonic, radiatively cooled and driven by the pressure of the toroidal magnetic field in a `magnetic tower' configuration. The 1 MA, 250 ns current pulse from the MAGPIE generator is introduced into a radial foil, an aluminium disc held between two concentric electrodes. The ablation of plasma from the foil close to the central electrode forms a radial gap which triggers the formation of the jets. Several diagnostics including magnetic and inductive probes were used to study their dynamics, particularly their launching mechanism. The similarities with previous single-episode magnetic tower jets from radial wire arrays together with new measurements of dimensionless parameters such as the magnetic Reynolds number (ReM>400) indicate that the experiments can be scaled to astrophysical jets.

Suzuki-Vidal, F.; Lebedev, S. V.; Bland, S. N.; Burdiak, G.; Chittenden, J. P.; Hall, G. N.; Harvey-Thompson, A. J.; Khoory, E.; Pickworth, L.; Swadling, G.; Ciardi, A.; Stehle, C.

2009-11-01

406

Tall Tower and Aircraft Measurements of Carbon Dioxide: Prospects for the North American Carbon Program (NACP)  

NASA Astrophysics Data System (ADS)

For over 10 years we have monitored carbon dioxide mixing ratios over North America from tall (up to 600 m) transmitter towers and aircraft (up to 8 km). The data, though sparse, give a measure of the temporal and 3D spatial variability of CO2 over the continent. Analysis of these data suggest ways in which measurements from a more extensive network of sites, such as is envisioned for the NACP, could be used to estimate net CO2 surface fluxes on a regional scale (i.e., roughly one million square kilometers). We also evaluate the use of mixing ratio data from short (30-100 m) towers for regional flux estimates. Short towers are widely used for local scale (a few hectares) measurements of atmosphere/surface exchange of CO2 (FLUXNET). The results indicate that measurements of CO2 mixing ratios at continental tower sites can be used to constrain estimates of regional CO2 fluxes. However, at present CO2 mixing ratios are measured with sufficient accuracy relative to global reference gas standards at only a few continental sites.

Bakwin, P.

2003-04-01

407

Elementary Kaluza-Klein towers revisited  

SciTech Connect

Considering that the momentum squared in the extra dimensions is the physically relevant quantity for the generation of the Kaluza-Klein mass states, we have reanalyzed mathematically the procedure for five dimensional scalar fields within the Arkhani-Ahmed, Dimopoulos and Dvali scenario. We find new sets of physically allowed boundary conditions. Beside the usual results, they lead to new towers with non regular mass spacing, to lonely mass states and to tachyons.

Grard, Fernand [Physique Generale et Physique des Particules Elementaires, Universite de Mons-Hainaut, 20 Place du Parc, 7000 Mons (Belgium); Nuyts, Jean [Physique Theorique et Mathematique, Universite de Mons-Hainaut, 20 Place du Parc, 7000 Mons (Belgium)

2006-12-15

408

Legionella in Puerto Rico cooling towers  

SciTech Connect

Water samples from air conditioning cooling towers receiving different treatment protocols on five large municipal buildings in San Juan, Puerto Rico were assayed for various species and serogroups of Legionella spp. using direct immunofluorescence. Several water quality parameters were also measured with each sample. Guinea pigs were inoculated with water samples to confirm pathogenicity and recover viable organisms. Legionella pneumophila (1-6), L. bozemanii, L. micdadei, L. dumoffii, and L. gormanii were observed in at least one of the cooling towers. L. pneumophila was the most abundant species, reaching 10{sup 5} cells/ml, within the range that is considered potentially pathogenic to humans. A significantly higher density of L. pneumophila was observed in the cooling tower water that was not being treated with biocides. Percent respiration (INT) and total cell activity (AODC), were inversely correlated with bacterial density. This study demonstrates that Legionella spp. are present in tropical air-conditioning cooling systems, and without continuous biocide treatment may reach densities that present a health risk.

Negron-Alviro, A.; Perez-Suarez, I.; Hazen, T.C. [Univ. of Puerto Rico, Rio Piedras (Puerto Rico)

1988-12-31

409

Harnessing wind power  

NASA Astrophysics Data System (ADS)

The design goals, test results, operating mechanisms, and ultimate limits of large wind energy conversion systems (WECS) are explored. NASA is currently managing and monitoring the performance of the Mod O, Mod OA, Mod 1, and Mod 2 wind turbines, which produce from 100 kW-2.5 MWe for grid interconnection. The Mod 2 machines have a 300 ft diam rotor, begin producing at 14 mph and achieve the rated output at 20 mph. Testing has shown the necessity of incorporating partial span pitch control, a flexible shaft, yaw control, microprocessor monitored wind condition sensors, and a soft-shell tower to lower vibration hazards with WECS. Large WECS have proved to be relatively nonpolluting, although some television and radio interference is present. Institutional issues for the protection of land, of aircraft flight paths, and for utility interconnect are outlined, and large WECS development programs in Denmark, Sweden, Spain, and Germany are described.

Fagenbaum, J.

1982-04-01

410

Wind speed and direction shears with associated vertical motion during strong surface winds  

NASA Technical Reports Server (NTRS)

Strong surface winds recorded at the NASA 150-Meter Ground Winds Tower facility at Kennedy Space Center, Florida, are analyzed to present occurrences representative of wind shear and vertical motion known to be hazardous to the ascent and descent of conventional aircraft and the Space Shuttle. Graphical (percentage frequency distributions) and mathematical (maximum, mean, standard deviation) descriptions of wind speed and direction shears and associated updrafts and downdrafts are included as functions of six vertical layers and one horizontal distance for twenty 5-second intervals of parameters sampled simultaneously at the rate of ten per second during a period of high surface winds.

Alexander, M. B.; Camp, D. W.

1984-01-01

411

Wind Turbine Safety and Function Test Report for the Gaia-Wind 11-kW Wind Turbine  

SciTech Connect

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers to wind energy expansion by providing independent testing results for small wind turbines (SWT). In total, four turbines were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety and function testing is one of up to five tests performed on the turbines, including power performance, duration, noise, and power-quality tests. The results of the testing provide the manufacturers with reports that can be used for small wind turbine certification. The test equipment includes a Gaia-Wind 11-kW wind turbine mounted on an 18-m monopole tower. Gaia-Wind Ltd. manufactured the turbine in Denmark. The system was installed by the NWTC site operations group with guidance and assistance from Gaia-Wind.

Huskey, A.; Bowen, A.; Jager, D.

2010-01-01

412

The 100 kW experimental wind turbine generator project  

NASA Technical Reports Server (NTRS)

The Energy Research and Development Administration and the NASA Lewis Research Center engaged jointly in a Wind Energy Program which included the design and erection of a 100 kW wind turbine generator. This test machine consists of a rotor turbine, transmission, shaft, alternator, and tower. The rotor, measuring 125 feet in diameter and consisting of two variable pitch blades, operates at 40 rpm and generates 100 kW of electrical power at a wind velocity of 18 mph. The entire assembly is placed on top of a tower 100 feet above ground level. The machine was scheduled to be ready for operation in August, 1975.

Puthoff, R. L.; Sirocky, P.

1975-01-01

413

RCS and radar propagation near offshore wind farms  

Microsoft Academic Search

The wind farm impact on marine radars has not been widely reported. Some past publications have touched on the subject but there has been no accurate model in place to readily examine the effects of different farm geometries, tower shapes and turbine sizes. This paper discusses the radar propagation modeling near offshore wind farms including the methods used to model

Laith S Rashid; Anthony K Brown

2007-01-01

414

WIND TUNNEL INVESTIGATION OF THE RESPONSE OF A SONIC ANEMOMETER  

EPA Science Inventory

An Applied Technology Inc. (ATI) sonic of the type used by J. C. Kaimal at the Boulder Tower was tested in the large wind tunnel at the U.S. EPA Fluid Modeling Facility. The wind tunnel is approximately 6 ft high, 10 ft wide with a test section bed 60 ft long. The air speed in th...

415

The economic optimisation of horizontal axis wind turbine design  

Microsoft Academic Search

A method for determining the optimum design parameters for horizontal axis wind turbines was developed and tested. These design parameters were the rotor diameter, rated power and tower height. The optimum values were found to be dependent on site wind regime. The results of the study indicated that it was, however, only the optimisation of the relative combination of rotor

G. R. Collecutt; R. G. J. Flay

1996-01-01

416

System management of a wind-energy converter  

Microsoft Academic Search

Wind energy converters are commonly used in converting wind energy into useful mechanical and electrical energies. But the problems of smooth start, tower effect and oscillations caused by aerodynamic forces acting on the rotor cause fluctuations in its power output. A system management was designed to reduce these effects. It consists of a microcontroller. This was verified with the help

Charles Lemogo Kana; Manoharan Thamodharan; Albrecht Wolf

2001-01-01

417

High Tip Speed Operation for Offshore Wind Turbines  

Microsoft Academic Search

Summary The operation of large offshore wind turbines at high rotational speeds is investigated with focus on rotor aerodynamics, performance for the extended operational range and the potential for tower top mass reductions. 2D aerodynamic investigations were carried out with the program XFOIL on the NACA 63415 airfoil. Several 5 MW wind turbine rotors were designed to operate at tip

Andreas Knauer; Tor David Hanson

418

The measurement of the ground wind structure at Wallops Island  

NASA Technical Reports Server (NTRS)

The mean and turbulence characteristics of the surface wind measured near the Atlantic coast were measured. The experimental data were acquired from a 76 meter tall instrumented micrometeorological tower. Mean wind and turbulence measurements were made with two types of instrumentation consisting of cup vane and temperature probes, primarily used for mean profile measurements of velocity and temperature respectively. The second system, a hot film and thermocouple system, was used for measurement of turbulence variances and covariances and spectra. The cup vane system was used to acquire data from all wind directions, while the hot film system was primarily used for turbulence measurements from the two prevailing wind directions, south and northwest. The micrometeorological tower is a self standing nonguyed tower with five working platforms at 15.2m (50 ft.) intervals, with cup vane and aspirated temperature probes mounted at each platform.

Tielman, H. W.

1981-01-01

419

Simplified modeling for wind turbine modal analysis using NASTRAN  

NASA Technical Reports Server (NTRS)

A detailed finite element model of the MOD-0 wind turbine tower was reduced to six beam elements (stick model). The method used to calculate the properties of the beam elements in the stick model was explained and the accuracy of the stick model in predicting natural frequencies and mode shapes was examined. Computer times were compared and several applications where the stick model was used are described. From results obtained from the MOD-0 tower it is concluded that a tower of this type can be modeled as a simple cantilever beam for modal analysis. However, this model should be limited to tower torsional modes and tower bending modes where the mode shape resembles a cantilever beam first bending mode shape.

Sullivan, T. L.

1978-01-01

420

Wind resource characterization results to support the Sandia Wind Farm Feasibility Study : August 2008 through March 2009.  

SciTech Connect

Sandia National Laboratories Wind Technology Department is investigating the feasibility of using local wind resources to meet the requirements of Executive Order 13423 and DOE Order 430.2B. These Orders, along with the DOE TEAM initiative, identify the use of on-site renewable energy projects to meet specified renewable energy goals over the next 3 to 5 years. A temporary 30-meter meteorological tower was used to perform interim monitoring while the National Environmental Policy Act (NEPA) process for the larger Wind Feasibility Project ensued. This report presents the analysis of the data collected from the 30-meter meteorological tower.

Deola, Regina Anne

2010-01-01

421

Basic principles and recent observations of rotationally sampled wind  

NASA Technical Reports Server (NTRS)

The concept of rotationally sampled wind speed is described. The unusual wind characteristics that result from rotationally sampling the wind are shown first for early measurements made using an 8-point ring of anemometers on a vertical plane array of meteorological towers. Quantitative characterization of the rotationally sampled wind is made in terms of the power spectral density function of the wind speed. Verification of the importance of the new concept is demonstrated with spectral analyses of the response of the MOD-OA blade flapwise root bending moment and the corresponding rotational analysis of the wind measured immediately upwind of the MOD-OA using a 12-point ring of anemometers on a 7-tower vertical plane array. The Pacific Northwest Laboratory (PNL) theory of the rotationally sampled wind speed power spectral density function is tested successfully against the wind spectrum measured at the MOD-OA vertical plane array. A single-tower empirical model of the rotationally sampled wind speed is also successfully tested against the measurements from the full vertical plane array. Rotational measurements of the wind velocity with hotfilm anemometers attached to rotating blades are shown to be accurate and practical for research on winds at the blades of wind turbines. Some measurements at the rotor blade of a MOD-2 turbine using the hotfilm technique in a pilot research program are shown. They are compared and contrasted to the expectations based upon application of the PNL theory of rotationally sampled wind to the MOD-2 size and rotation rate but without teeter, blade bending, or rotor induction accounted for. Finally, the importance of temperature layering and of wind modifications due to flow over complex terrain is demonstrated by the use of hotfilm anemometer data, and meteorological tower and acoustic doppler sounder data from the MOD-2 site at Goodnoe Hills, Washington.

Connell, James R.

1995-01-01

422

Plant Light Stress Tolerance across the New Mexico Elevation Gradient: Scaling from Leaf to Tower  

NASA Astrophysics Data System (ADS)

Excess light is a major abiotic component of plant stress especially when combined with sustained periods of drought. Arid and semi-arid ecosystems are regularly exposed to sustained high light, low water conditions. A network of nine Eddy Covariance towers oriented along an elevation gradient in central New Mexico has been utilized to assess differences in light use efficiency and light stress response across six distinct biomes, all of which are subjected to a semi-arid climate regulated by a seasonal monsoon. Leaf level measurements of effective quantum yield (?PSII ) and non-photochemical quenching (NPQ) parameters were taken at five of these biomes pre and post monsoon using branch mounted and hand held pulse amplitude modulated (PAM) fluorometers. Diurnal samples of leaf tissue were snap frozen to be analyzed for xanthophyll de-epoxidation state via high pressure liquid chromatography. We analyzed these leaf level parameters in the context of tower based and satellite derived measurements of NDVI, PRI and eddy covariance measures of ecosystem function including net ecosystem exchange and light use efficiency. This multi-biome, multi-scale approach aims to investigate not only leaf level photochemical response to excess light, but also how these responses are perceived by remote sensing platforms at flux tower and low earth orbit scales. We hypothesize that plant photochemical status with respect to light use efficiency and excess light mitigation strategies fluctuates as a function of elevation and the seasonal monsoon. We expect to see the highest regulatory capacity at low elevation, low precipitation sites. The NDVI and PRI signal from the tower level will track changes in ecosystem function with respect to NEE and be explained by differences in the ability of biome specific plant functional types to deal with excess light. The tower footprint, parameterized by plant functional type constituents, will be scaled to the landscape level by analysis of MODIS products.

Krofcheck, D. J.; Hanson, D.; Fox, A. M.; Litvak, M. E.

2010-12-01

423

Influence of Wind Turbulence on Yaw-control Gears in Wind Turbine  

NASA Astrophysics Data System (ADS)

This paper describes an influence of wind turbulence on yaw-control gears of nacelle in a wind power station. This site is located in Tappi cape of Aomori prefecture where is characterized by a big wind turbulence due to the western strong wind and a steep slope of the cape. In this paper two adjacent wind towers are dealt with among eleven ones. To clarify an influence of the wind turbulence on the leeward wind power generator. The measurement results showed that the turbulence and the standard deviation exceeded IEC Wind Turbine Standards frequently. Accordingly the torque applied to the yaw control gears vibrated with short time period and its magnitude was frequently larger than 4.8 ton-m (47kN-m) regarded as the metal fatigue limit. By the method where the output of the wind turbine generator is controlled, the magnitude of the vibrating torque can be reduced under the limit of the material fatigue.

Suzuki, Kazuo; Hoshino, Naoki; Inomata, Noboru; Kimura, Hiroshi; Fujiwara, Tamiya

424

Second tower experiment: Further evidence for Newtonian gravity  

NASA Astrophysics Data System (ADS)

An experimental test of the inverse-square law has been conducted on a 610 m television tower near Inverness, Mississippi. Gravity was measured at five elevations on the WABG tower, as well as on the surface within an 8 km radius surrounding the tower. These data were combined with archived data extending to 300 km, and all the surface data were corrected for terrain. Assuming the validity of the inverse-square law, the surface data were then analytically continued to predict gravity at each elevation on the tower where measurements were made. The tower observations were compared to the predictions, with the largest discrepancy being -33+/-30 ?Gal at 493 m. The results are in good agreement with previous tower experiments, which also are in accord with the inverse-square law, and they set further restrictions on possible non-Newtonian forces.

Romaides, Anestis J.; Sands, Roger W.; Eckhardt, Donald H.; Fischbach, Ephraim; Talmadge, Carrick L.; Kloor, Harry T.

1994-09-01

425

Forecasting Cool Season Daily Peak Winds at Kennedy Space Center and Cape Canaveral Air Force Station  

NASA Technical Reports Server (NTRS)

The expected peak wind speed for the day is an important element in the daily 24-Hour and Weekly Planning Forecasts issued by the 45th Weather Squadron (45 WS) for planning operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The morning outlook for peak speeds also begins the warning decision process for gusts ^ 35 kt, ^ 50 kt, and ^ 60 kt from the surface to 300 ft. The 45 WS forecasters have indicated that peak wind speeds are a challenging parameter to forecast during the cool season (October-April). The 45 WS requested that the Applied Meteorology Unit (AMU) develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. The tool must only use data available by 1200 UTC to support the issue time of the Planning Forecasts. Based on observations from the KSC/CCAFS wind tower network, surface observations from the Shuttle Landing Facility (SLF), and CCAFS upper-air soundings from the cool season months of October 2002 to February 2007, the AMU created multiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence, the temperature inversion depth, strength, and wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft. Six synoptic patterns were identified: 1) surface high near or over FL, 2) surface high north or east of FL, 3) surface high south or west of FL, 4) surface front approaching FL, 5) surface front across central FL, and 6) surface front across south FL. The following six predictors were selected: 1) inversion depth, 2) inversion strength, 3) wind gust factor, 4) synoptic weather pattern, 5) occurrence of precipitation at the SLF, and 6) strongest wind in the lowest 3000 ft. The forecast tool was developed as a graphical user interface with Microsoft Excel to help the forecaster enter the variables, and run the appropriate regression equations. Based on the forecaster's input and regression equations, a forecast of the day's peak and average wind is generated and displayed. The application also outputs the probability that the peak wind speed will be ^ 35 kt, 50 kt, and 60 kt.

Barrett, Joe, III; Short, David; Roeder, William

2008-01-01

426

Sharing from Scratch: How To Network CD-ROM.  

ERIC Educational Resources Information Center

Examines common CD-ROM networking architectures: via existing operating systems (OS), thin server towers, and dedicated servers. Discusses digital video disc (DVD) and non-CD/DVD optical storage solutions and presents case studies of networks that work. (PEN)

Doering, David

1998-01-01

427

Earthquake Response Modeling for a Parked and Operating Megawatt-Scale Wind Turbine.  

National Technical Information Service (NTIS)

Demand parameters for turbines, such as tower moment demand, are primarily driven by wind excitation and dynamics associated with operation. For that purpose, computational simulation platforms have been developed, such as FAST, maintained by the National...

2010-01-01

428

Combined effects of deterministic and random loads in wind turbine design  

Microsoft Academic Search

Deficiencies of modeling the deterministic loading on wind turbine blades as a cumulative sum of wind shear, mean wind, tower shadow, gravitational, and centrifugal forces are examined. It is analytically shown by application of the Palmgren-Miner rule that periodic loadings which coincide in cycle result in damage exceeding the sum of the individual stresses. The necessity of calculating the probability

A. Raab

1980-01-01

429

Wind Energy Opportunities, Challenges, and Progress Within the Federal Government (Poster)  

SciTech Connect

Wind Powering America (WPA) works with Federal agencies to increase their understanding of wind resources and assessment; facilitate project development activities through Met tower loans, wind data analysis, and technical assistance; and provide advice on RFP development and financing options. This poster provides an overview of WPA's activities with the federal sector.

Robichaud, R.

2009-05-01

430

37. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER. THIS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

37. VIEW LOOKING SOUTH AT THE STATIC TEST TOWER. THIS VIEW SHOWS TWO MAJOR CHANGES TO THE STATIC TEST TOWER: THE ADDITION OF THE NASA LOGO TO THE FACADE AND THE ADDITION OF THE UPPER STAGES TO THE JUPITER MISSILE IN THE WEST POSITION ON THE TOWER TO REPRESENT THE JUNO II CONFIGURATION. 1961, PHOTOGRAPHER UNKNOWN, FRED ORDWAY COLLECTION, U. S. SPACE AND ROCKET CENTER, HUNTSVILLE, AL. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

431

Panel resonant behavior of wind turbine blades  

Microsoft Academic Search

The principal design drivers in the certification of wind turbine blades are ultimate strength, fatigue resistance, adequate tip-tower clearance, and buckling resistance. Buckling resistance is typically strongly correlated to both ultimate strength and fatigue resistance. A composite shell with spar caps forms the airfoil shape of a blade and reinforcing shear webs are placed inside the blade to stiffen the

Joshua A. Paquette; Daniel Todd Griffith

2010-01-01

432

Wind turbine generator with improved operating subassemblies  

Microsoft Academic Search

A wind turbine includes a yaw spring return assembly to return the nacelle from a position to which it has been rotated by yawing forces, thus preventing excessive twisting of the power cables and control cables. It also includes negative coning restrainers to limit the bending of the flexible arms of the rotor towards the tower, and stop means on

Cheney Jr

1985-01-01

433

Large Wind Energy Converter: Growian 3 MW  

NASA Technical Reports Server (NTRS)

The final report on the projected application of larger-scale wind turbine on the northern German coast is summarized. The designs of the tower, machinery housing, rotor, and rotor blades are described accompanied various construction materials are examined. Rotor blade adjustment devices auxiliary and accessory equipment are examined.

Feustel, J. E.; Helm, S.; Koerber, F.

1980-01-01

434

Solar power tower development: Recent experiences  

SciTech Connect

Recent experiences with the 10 MW{sub e} Solar Two and the 2.5 MW{sub t} TSA (Technology Program Solar Air Receiver) demonstration plants are reported. The heat transfer fluids used in these solar power towers are molten-nitrate salt and atmospheric air, respectively. Lessons learned and suggested technology improvements for next-generation plants are categorized according to subsystem. The next steps to be taken in the commercialization process for each these new power plant technologies is also presented.

Tyner, C.; Kolb, G.; Prairie, M. [and others

1996-12-01

435

View of commissary, central guard tower, and cell block five, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of commissary, central guard tower, and cell block five, looking from the chapel stairs, facing southeast - Eastern State Penitentiary, 2125 Fairmount Avenue, Philadelphia, Philadelphia County, PA

436

Optimal Inflatable Space Towers with 3 - 100 km Height  

NASA Technical Reports Server (NTRS)

Theory and computations are provided for building inflatable space towers up to one hundred kilometers in height. These towers can be used for tourism, scientific observation of space, observation of the Earth's surface, weather and upper atmosphere, and for radio, television, and communication transmissions. These towers can also be used to launch space ships and Earth satellites. These projects are not expensive and do not require rockets. They require thin strong films composed from artificial fibers and fabricated by current industry. The towers can be built using present technology. The towers can be used (for tourism, communication, etc.) during the construction process and provide self-financing for further construction. The tower design does not require work at high altitudes; all construction can be done at the Earth's surface. The transport system for a tower consists of a small engine (used only for friction compensation) located at the Earth's surface. The tower is separated into sections and has special protection mechanisms in case of damage. Problems involving security, control, repair, and stability of the proposed towers are addressed in other publications. The author is prepared to discuss these and other problems with serious organizations desiring to research and develop these projects.

Bolonkin, Alexander

2003-01-01

437

ground floor plan, sections, tower pier detail, columns & pilasters, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ground floor plan, sections, tower pier detail, columns & pilasters, keystone detail, typical windows, sections - Union League of Philadelphia, 140 South Broad Street, Philadelphia, Philadelphia County, PA

438

10. Observation tower atop Clingman's Dome looking SE. Great ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. Observation tower atop Clingman's Dome looking SE. - Great Smoky Mountains National Park Roads & Bridges, Clingmans Dome Road, Between Newfound Gap Road & Clingmans Dome, Gatlinburg, Sevier County, TN

439

The Damaging Effects of Earthquake Excitation on Concrete Cooling Towers  

SciTech Connect

Reinforced concrete cooling towers of hyperbolic shell configuration find widespread application in utilities engaged in the production of electric power. In design of critical civil infrastructure of this type, it is imperative to consider all the possible loading conditions that the cooling tower may experience, an important loading condition in many countries is that of the earthquake excitation, whose influence on the integrity and stability of cooling towers is profound. Previous researches have shown that the columns supporting a cooling tower are sensitive to earthquake forces, as they are heavily loaded elements that do not possess high ductility, and understanding the behavior of columns under earthquake excitation is vital in structural design because they provide the load path for the self weight of the tower shell. This paper presents the results of a finite element investigation of a representative 'dry' cooling tower, using realistic horizontal and vertical acceleration data obtained from the recent and widely-reported Tabas, Naghan and Bam earthquakes in Iran. The results of both linear and nonlinear analyses are reported in the paper, the locations of plastic hinges within the supporting columns are identified and the ramifications of the plastic hinges on the stability of the cooling tower are assessed. It is concluded that for the (typical) cooling tower configuration analyzed, the columns that are instrumental in providing a load path are influenced greatly by earthquake loading, and for the earthquake data used in this study the representative cooling tower would be rendered unstable and would collapse under the earthquake forces considered.

Abedi-Nik, Farhad [SADRA Institute of Higher Education, Tehran (Iran, Islamic Republic of); Sabouri-Ghomi, Saeid [K.N.T University of Technology, Tehran (Iran, Islamic Republic of)

2008-07-08

440

8. STATIC TEST TOWER NORTHWEST ELEVATION FROM THE POWER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. STATIC TEST TOWER - NORTHWEST ELEVATION FROM THE POWER PLANT TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

441

2D-4D correspondence: Towers of kinks versus towers of monopoles in N=2 theories  

NASA Astrophysics Data System (ADS)

We continue to study the BPS spectrum of the N=(2,2) CPN-1 model with the ZN-symmetric twisted mass terms. We focus on analysis of the “extra” towers found previously in [P. A. Bolokhov, M. Shifman, and A. Yung, arXiv:1104.5241], and compare them to the states that can be identified in the quasiclassical domain. Exact analysis of the strong-coupling states shows that not all of them survive when passing to the weak-coupling domain. Some of the states decay on the curves of the marginal stability. Thus, not all strong-coupling states can be analytically continued to weak coupling to match the observable bound states. At weak coupling, we confirm the existence of bound states of topologically charged kinks and elementary quanta. Quantization of the U(1) kink modulus leads to formation of towers of such states. For the ZN-symmetric twisted masses their number is by far less than N-1 as was conjectured previously. We investigate the quasiclassical limit and show that out of N possible towers only two survive in the spectrum for odd N, and a single tower for even N. In the case of CP2 theory the related curves of the marginal stability are discussed in detail. In these points we overlap and completely agree with the results of Dorey and Petunin. We also comment on 2D-4D correspondence.

Bolokhov, Pavel A.; Shifman, Mikhail; Yung, Alexei

2012-04-01

442

Deconstructing the Tower: Parameters and Predictors of Problem Difficulty on the Tower of London Task  

ERIC Educational Resources Information Center

The Tower of London (TOL) task has been widely used in both clinical and research realms. In the current study, 104 healthy participants attempted all possible moderate- to high-difficulty TOL problems in order to determine: (1) optimal measures of problem solving performance, (2) problem characteristics, other than the minimum moves necessary to…

Berg, W. Keith; Byrd, Dana L.; McNamara, Joseph P. H.; Case, Kimberly

2010-01-01

443

An analysis of the weather research and forecasting model for wind energy applications in Wyoming  

NASA Astrophysics Data System (ADS)

Determination of wind speeds at the hub height of wind turbines is an important focus of wind energy studies. Standard extrapolation methods are unable to accurately estimate 50-m winds from standard 10-m winds under stable conditions. Modeling of winds is an alternative. Daily numerical simulations from December 2011-November 2012 have been conducted using the Weather Research and Forecasting model (WRF) to evaluate its potential for determining wind speeds at hub height. Model simulations have been validated with data collected at the University of Wyoming Wind Tower (UWT). WRF was superior to operational models in predicting 10-m wind speeds at surface stations and at the UWT. Results from WRF also showed that biases are present; WRF tends to overestimate winds during low-wind events and underestimate winds during high-wind events. WRF has demonstrated skill in hub height wind forecasts for Wyoming that can be of use for wind farm planning and operation.

Siuta, David

444

Laboratory-scale experiments on wind turbine nacelle movement estimation  

NASA Astrophysics Data System (ADS)

The effect of nacelle motion should be considered when calculating the wind speed relative to the wind turbine structure, which is essential in wind turbine control and performance testing. A Kalman filter approach is applied to estimate the nacelle motion of a wind turbine. Information from several accelerometers and strain gauges which are installed on the wind turbine tower is combined with the Kalman filter. An optimization algorithm is used to choose the optimal locations for strain gauge and accelerometer installation. A laboratory-scale experimental rig which mimics the tower and nacelle of the wind turbine is constructed to evaluate the performance of the proposed estimator algorithm. The usefulness of the proposed algorithm is validated by these laboratory-scale experimental results.

Nam, Yoonsu; Yoon, Tai Jun

2009-11-01

445

Comparison of methane emissions from wetlands measured from aircraft and towers  

NASA Astrophysics Data System (ADS)

The ability to estimate surface fluxes from light, fixed-wing aircraft is investigated during two flights over Twitchell Island, a heavily managed peatland dominated by irrigated crops approximately 6 km x 3 km in the Sacramento Delta. Flux towers provide a continuous measurement at a single point, while airborne fluxes provide a snapshot of a large area at a given time. The ability to integrate the two methods would provide a means to estimate a continuous regional flux from tower measurements. The single engine airplane (Mooney TLS), provided by Scientific Aviation, was flown around the island while concurrent flux measurements (latent & sensible heat, CO2, CH4) were being made from 4 m towers at two locations on the surface. The flux estimate made with the airplane uses horizontal mean wind measured in real-time from the airplane and the methane mixing ratio measured onboard with a Picarro f2301 analyzer. During the flights there was clear periodicity in all scalars measured coincident with the flight time required to circle the island (~6 minutes), indicating a connection between the surface and the observed signal in the airplane. For methane, higher mixing ratios were observed on the downwind side of the island. An internal boundary layer was observed, which we believe resulted from the Montezuma Hills wind farms upwind of Twitchell Island. Scalars were well-mixed throughout the depth of that internal boundary layer (~500m), which is shown to be consistent with a theoretical estimate of the internal boundary layer given the transition from the wind farm to the island vegetation. Surface emissions were estimated using a mass-balance approach where each of the terms in the scalar budget equation are estimated using a least squares minimization of the data while the airplane was within 10 km of the center of the island and the altitude was below 300 meters. Surface emission of methane during the first flight was estimated at 36 × 13 nmol m-2 s-1. During the same time period, the flux measured from the ground stations within the rice fields on the island was estimated at 44 nmol m-2 s-1. The close agreement suggests that this technique has great potential for integrating flux tower measurements over larger areas.

Conley, S. A.; Faloona, I. C.; Drexler, J. Z.; Anderson, F. E.; Baldocchi, D. D.; Sturtevant, C. S.; Verfaillie, J. G.; Knox, S. H.

2013-12-01

446

Equatorial thermospheric winds: New results using data from a network of three Fabry-Perot interferometers located in central Peru  

NASA Astrophysics Data System (ADS)

A new observing strategy aimed at improving our understanding of the properties of the equatorial thermosphere wind field, such as the vorticity and divergence, has been developed to generate maps of the thermospheric wind field. Estimates of the neutral wind are obtained from measurements of the Doppler shift of the thermospheric 630.0-nm emission obtained from a sequence of eight evenly spaced azimuthal directions for each of the three Fabry-Perot interferometer (FPI) observatories located in central Peru (Jicamarca, Nazca, and Arequipa). Measurements towards the zenith and a frequency-stabilized laser reference are also included in each sequence, which takes ~25 minutes to complete. Six of the off-zenith observing directions from the Nazca FPI observatory are used to make common volume (CV) measurements, where two of the FPIs observe the same thermospheric volume with a centroid height of ~250 km at orthogonal angles. These CV positions are located ~225 km north and south of the Nazca FPI observatory. The data obtained during a coordinated observation of the two FPIs observing the same CV location are used to compute estimates of the zonal (u) and meridional (v) wind components. The set of Doppler shifts measured by the three FPIs during a single sequence is used to produce a map of the neutral wind field for that period of time. The construction of this map is based upon the use of a first-order polynomial expansion of the neutral wind field relative to the site coordinates of each FPI location. This expansion includes the first-order gradients of u and v with respect to the zonal (x) and meridional (y) directions. Computation of the best fit in a linear least squares sense of the model expansion parameters to the Doppler shift data for all three sites determines the values of these gradient parameters. Results obtained for mid-winter 2013 show the anti-cyclonic circulation expected near the terminator generated by the day-to-night pressure gradient. Sequences of maps generated prior to midnight also illustrate how the zonal eastward circulation is modified by the introduction of the semi-diurnal tidal flow toward the geographic equator followed by the poleward reversal of this flow four to six hours later as the midnight pressure bulge passes poleward through central Peru. This technique of mapping the thermospheric wind field will be valuable as a tool for studying the variability and spatial structure of thermospheric winds near the geographic equator and may be used elsewhere for the same purpose.

Meriwether, J. W.; Dominquez, L. N.; Milla, M. A.; Chau, J. L.; Makela, J. J.; Fisher, D.

2013-12-01

447

On the role of “hot towers” in tropical cyclone formation  

Microsoft Academic Search

Summary The probabilistic approach to tropical cyclogenesis is advanced here by examining the role of convection in the early stages. The development of “hot towers”, that is tall cumulonimbus towers which reach or penetrate the tropopause, and their role in tropical cyclogenesis is investigated in two well-documented cases of formation. namely hurricane Daisy (1958) in the Atlantic and Tropical Cyclone

J. Simpson; J. B. Halverson; B. S. Ferrier; W. A. Petersen; R. H. Simpson; R. Blakeslee; S. L. Durden

1998-01-01

448

Environmental Impacts from the Operation of Cooling Towers at SRP  

Microsoft Academic Search

An assessment has been made of the environmental effects that would occur from the operation of cooling towers at the SRP reactors. A more realistic numerical model of the cooling tower plume has been used to reassess the environmental impacts. The following effects were considered: (1) the occurrence of fog and ice and their impact on nearby structures, (2) drift

2001-01-01

449

13. Infield road in SW part of infield. Tower in ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Infield road in SW part of infield. Tower in distance is the '7/8 Mile' observation tower. See photo WA-201-14. In distance on left is the Jockey Building. (May 1993) - Longacres, 1621 Southwest Sixteenth Street, Renton, King County, WA

450

PBF Cooling Tower. View of stairway to fan deck. Vents ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PBF Cooling Tower. View of stairway to fan deck. Vents are made of redwood. Camera facing southwest toward north side of Cooling Tower. Siding is corrugated asbestos concrete. Photographer: Kirsh. Date: June 6, 1969. INEEL negative no. 69-3463 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

451

18. Upstream face of arches, concrete placing tower is at ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. Upstream face of arches, concrete placing tower is at far right. Tower at center was used to convey material. Photographer unknown, January 29, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

452

54. Angled view looking up at Brooklyn Tower showing juncture ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

54. Angled view looking up at Brooklyn Tower showing juncture of deck superstructure with the tower and diagonal cables. Jet Lowe, photographer, 1982. - Brooklyn Bridge, Spanning East River between Park Row, Manhattan and Sands Street, Brooklyn, New York, New York County, NY

453

PBF Cooling Tower contextual view. Camera facing southwest. West wing ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PBF Cooling Tower contextual view. Camera facing southwest. West wing and north facade (rear) of Reactor Building (PER-620) is at left; Cooling Tower to right. Photographer: Kirsh. Date: November 2, 1970. INEEL negative no. 70-4913 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

454

36. EASTERN VIEW OF BOTTOM CONE OF GAS COOLING TOWER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

36. EASTERN VIEW OF BOTTOM CONE OF GAS COOLING TOWER No. 1 AND TWO GAS COOLING TOWER SERVICE WATER PUMPS IN THE GAS WASHER PUMP HOUSE. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

455

Jacket, Deck, and Pipeline Installation-Lena Guyed Tower  

Microsoft Academic Search

The installation of Exxon's Lena guyed tower set two new offshore records when the longest one-piece jacket was positioned on the seafloor and eight main piles were driven to 560 feet. The overall installation of the guyed tower jacket, decks, and pipelines required a variety of offshore installation procedures and extensive project planning. To minimize the potential for damage to

E. C. Smetak; J. Lombardi; H. J. Roussel; T. C. Wozniak

1984-01-01

456

8. INTERIOR VIEW OF ASSEMBLY ROOM (REAR FACADE), UNTANKING TOWER, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. INTERIOR VIEW OF ASSEMBLY ROOM (REAR FACADE), UNTANKING TOWER, SHOWING PREVIOUS MODIFICATIONS (INSTALLATION OF METAL ROLL-UP DOOR, LEFT FOREGROUND). 125-TON LIFTING CRANE (TOP FOREGROUND), AND ORIGINAL FLOOR-TO-CEILING MULTI-PANE, METAL-CASED WINDOWS - Bonneville Power Administration Chehalis Substation, Untanking Tower, State Route 603, West of Interstate 5, Napavine, Lewis County, WA

457

NORTH FRONT AND WEST SIDE, HIGH ENCLOSED METAL OBSERVATION TOWER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

NORTH FRONT AND WEST SIDE, HIGH ENCLOSED METAL OBSERVATION TOWER LOCATED APPROXIMATELY 1800 FEET SOUTH OF TRACK. Looking southeast - Edwards Air Force Base, South Base Sled Track, Observation Tower, South of west end of Sled Track, Lancaster, Los Angeles County, CA

458

Simulation of an Integrated Steam Generator for Solar Tower  

Microsoft Academic Search

Optical and thermal simulation of a new solar tower steam generator is presented. The steam generator, placed on top of a solar tower, has two integrated receivers, external for boiling the steam and a cavity for its superheating. These two parts of the solar steam generator are facing different sections in a surrounding heliostat field and therefore can be operated

R. Ben-Zvi; M. Epstein; A. Segal

459

HARMON HOUSE ELEVATION VIEW OF WEST FAÇADE WITH OCTAGONAL TOWER. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HARMON HOUSE ELEVATION VIEW OF WEST FAÇADE WITH OCTAGONAL TOWER. (The house was reroofed in the fall of 2006, after an attic fire in March of that same year. Image also shows Flora A. Engle?s octagon tower addition, the front entry to the house, and brooding chickens.) - Engle Farm, House, 89 South Ebey Road, Coupeville, Island County, WA

460

Optimal Electrostatic Space Tower (Mast, New Space Elevator)  

Microsoft Academic Search

Author offers and researched the new and revolutionary inflatable electrostatic AB space towers (mast, new space elevator) up to one hundred twenty thousands kilometers (or more) in height. The main innovation is filling the tower by electron gas, which can create pressure up one atmosphere, has negligible small weight and surprising properties. The suggested mast has following advantages in comparison

Alexander A. Bolonkin

2007-01-01

461

10. View east from northwest (port) elevator tower to northeast ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. View east from northwest (port) elevator tower to northeast (starboard) elevator tower. Muzzle of deck torpedo tube projects from wall at lower right. - Naval Torpedo Station, Firing Pier, North end of Gould Island in Narragansett Bay, Newport, Newport County, RI

462

34. VIEW LOOKING NORTHEAST AT THE STATIC TEST TOWER. MODIFICATIONS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

34. VIEW LOOKING NORTHEAST AT THE STATIC TEST TOWER. MODIFICATIONS TO THE EAST SIDE OF THE TOWER ARE NEARING COMPLETION. NOTE THAT THE HORIZON HAS BEEN MODIFIED TO DISGUISE THE LOCATION. 1959, PHOTOGRAPHER UNKNOWN, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

463

7. SOUTHWEST CORNER OF EAST PHOTO TOWER. CLOSED WINDOW ON ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. SOUTHWEST CORNER OF EAST PHOTO TOWER. CLOSED WINDOW ON WEST SIDE; ELECTRICAL POWER BOX ON EAST SIDE OF PHOTO TOWER. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

464

Update on the Purdue University 2-second Drop Tower  

Microsoft Academic Search

A small drop tower of approximately one second drop duration was built in the School of Aero-nautics and Astronautics at Purdue University beginning in 1998 and operated until summer 2007. This inexpensive tower in an old airplane hanger, was built largely by Yongkang Chen, now a Research Professor at Portland State University in Oregon, USA. In about 7 years of

Steven Collicott

2010-01-01

465

13. View of Truss tower and pivot pier locking east. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. View of Truss tower and pivot pier locking east. When the draw is open, the two arms of the truss act as cantilevers supported by the truss tower. A counterweight in the shorter of the bridge keeps the span in proper balance. - Center Street Swing Bridge, Southwest of Public Square, Cleveland, Cuyahoga County, OH

466

VIEW LOOKING NW FROM CATWALK OF SE TOWER, SHOWING INTERIOR ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW LOOKING NW FROM CATWALK OF SE TOWER, SHOWING INTERIOR ELEVATION OF TOWER OPPOSITE. NOTE THAT CONCRETE PIERS DO NOT MATCH FOOTINGS PROJECTING SLIGHTLY ABOVE WATER. - Lake Shore & Michigan Southern Railway, Bridge No. 6, Spanning Calumet River, east of Chicago Skyway (I-90), Chicago, Cook County, IL

467

15. Como gatehouse (outlet tower) and access bridge, looking west ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. Como gatehouse (outlet tower) and access bridge, looking west from dam crest (Trash rack visible in reservoir pool behind and right of tower) - Bitter Root Irrigation Project, Como Dam, West of U.S. Highway 93, Darby, Ravalli County, MT

468

32. VIEW LOOKING EAST AT THE STATIC TEST TOWER WHILE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. VIEW LOOKING EAST AT THE STATIC TEST TOWER WHILE A JUPITER MISSILE IS BEING POSITIONED ONTO THE TEST TOWER. DATE AND PHOTOGRAPHER UNKNOWN, MSFC PHOTO LAB. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

469

8. SOUTH SIDE OF EAST PHOTO TOWER; ELECTRICAL POWER BOX ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. SOUTH SIDE OF EAST PHOTO TOWER; ELECTRICAL POWER BOX ON RIGHT. LEFT TO RIGHT IN BACKGROUND: A STORAGE SHED (BLDG. 776), METEOROLOGICAL TOWER, PYROTECHNIC SHED (BLDG. 757), AND SLC-3W MST. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

470

User's manual: cooling-tower-plume prediction code  

Microsoft Academic Search

This report presents the theory and user's guide to a mathematical model for the prediction of the seasonal\\/annual physical impacts of cooling tower plumes, drift, fogging, icing, and shadowing. The model is aimed at providing predictions that may be used in the licensing of power plants with cooling towers. The submodels for these physical impacts provide improvements in theory and

A. J. Policastro; L. Coke; M. Wastag

1984-01-01

471

Operations Concept for the TCCC (Tower Control Computer Complex) Man-Machine Interface.  

National Technical Information Service (NTIS)

Operations Concept for the TCCC Man-Machine Interface analyzes the tower Air Traffic Controller's job in the Tower Control Computer Complex (TCCC) environment. It considers the operations in today's towers and the automated capabilities planned for the TC...

H. L. Ammerman E. S. Becker L. J. Bergen D. K. Davies E. E. Inman

1986-01-01

472

75 FR 63802 - Action Affecting Export Privileges; Parto Abgardan Cooling Towers Co.  

Federal Register 2010, 2011, 2012, 2013

...Affecting Export Privileges; Parto Abgardan Cooling Towers Co. Parto Abgardan Cooling Towers Co., P.O. Box 966, Folsom, CA 95763...Making Denial of Export Privileges of Aqua-Loop Cooling Towers, Co. Applicable to Parto Abgardan...

2010-10-18

473

Improvement of the Environmental and Economic Characteristics of the Rotary Cooling Tower.  

National Technical Information Service (NTIS)

The report describes research for the past year on methods to enhance the environmental a